Aggregator

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Jul 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING OVER PORTIONS OF THE NORTHEAST US...AND OVER PARTS OF NORTH DAKOTA.... ...SUMMARY... Scattered storms capable of severe wind gusts and hail are forecast across the Northeast US and North Dakota on Thursday. ...Northeast... A shortwave trough currently over western Ontario will track southeastward across the Great Lakes on Thursday. Increasing large scale forcing will overspread parts of PA/NY and New England through the day, promoting afternoon thunderstorm development along an approaching cold front. A warm/humid air mass will be present ahead of the front, with steep low-level lapse rates and sufficient CAPE to pose a risk of damaging wind gusts and perhaps some hail. Given trends in 12z model guidance regarding thunderstorm coverage, have added a SLGT risk for portions of the region. ...ND... A prominent mid-level ridge will be established over the central US tomorrow. Model guidance suggests a subtle shortwave trough will track into eastern MT during the afternoon and top the ridge overnight. Southerly low-level winds will help to draw moisture northward into ND by late afternoon, resulting in a reservoir of strong instability. Thunderstorms are expected to develop over western ND posing a risk of large hail and damaging winds. Several 12z HREF members suggest the risk of upscale growth and a bowing MCS tracking eastward across ND overnight. ...Upper MS Valley... A weak/diffuse low-level baroclinic zone will extend from southeast MN into IL on Thursday. Strengthening southwesterly low-level winds will enhance warm advection by early evening, leading to scattered thunderstorms. A few of these storms could be strong, posing a risk of gusty winds and hail. ..Hart.. 07/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Jul 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING OVER PORTIONS OF THE NORTHEAST US...AND OVER PARTS OF NORTH DAKOTA.... ...SUMMARY... Scattered storms capable of severe wind gusts and hail are forecast across the Northeast US and North Dakota on Thursday. ...Northeast... A shortwave trough currently over western Ontario will track southeastward across the Great Lakes on Thursday. Increasing large scale forcing will overspread parts of PA/NY and New England through the day, promoting afternoon thunderstorm development along an approaching cold front. A warm/humid air mass will be present ahead of the front, with steep low-level lapse rates and sufficient CAPE to pose a risk of damaging wind gusts and perhaps some hail. Given trends in 12z model guidance regarding thunderstorm coverage, have added a SLGT risk for portions of the region. ...ND... A prominent mid-level ridge will be established over the central US tomorrow. Model guidance suggests a subtle shortwave trough will track into eastern MT during the afternoon and top the ridge overnight. Southerly low-level winds will help to draw moisture northward into ND by late afternoon, resulting in a reservoir of strong instability. Thunderstorms are expected to develop over western ND posing a risk of large hail and damaging winds. Several 12z HREF members suggest the risk of upscale growth and a bowing MCS tracking eastward across ND overnight. ...Upper MS Valley... A weak/diffuse low-level baroclinic zone will extend from southeast MN into IL on Thursday. Strengthening southwesterly low-level winds will enhance warm advection by early evening, leading to scattered thunderstorms. A few of these storms could be strong, posing a risk of gusty winds and hail. ..Hart.. 07/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Jul 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING OVER PORTIONS OF THE NORTHEAST US...AND OVER PARTS OF NORTH DAKOTA.... ...SUMMARY... Scattered storms capable of severe wind gusts and hail are forecast across the Northeast US and North Dakota on Thursday. ...Northeast... A shortwave trough currently over western Ontario will track southeastward across the Great Lakes on Thursday. Increasing large scale forcing will overspread parts of PA/NY and New England through the day, promoting afternoon thunderstorm development along an approaching cold front. A warm/humid air mass will be present ahead of the front, with steep low-level lapse rates and sufficient CAPE to pose a risk of damaging wind gusts and perhaps some hail. Given trends in 12z model guidance regarding thunderstorm coverage, have added a SLGT risk for portions of the region. ...ND... A prominent mid-level ridge will be established over the central US tomorrow. Model guidance suggests a subtle shortwave trough will track into eastern MT during the afternoon and top the ridge overnight. Southerly low-level winds will help to draw moisture northward into ND by late afternoon, resulting in a reservoir of strong instability. Thunderstorms are expected to develop over western ND posing a risk of large hail and damaging winds. Several 12z HREF members suggest the risk of upscale growth and a bowing MCS tracking eastward across ND overnight. ...Upper MS Valley... A weak/diffuse low-level baroclinic zone will extend from southeast MN into IL on Thursday. Strengthening southwesterly low-level winds will enhance warm advection by early evening, leading to scattered thunderstorms. A few of these storms could be strong, posing a risk of gusty winds and hail. ..Hart.. 07/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Jul 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING OVER PORTIONS OF THE NORTHEAST US...AND OVER PARTS OF NORTH DAKOTA.... ...SUMMARY... Scattered storms capable of severe wind gusts and hail are forecast across the Northeast US and North Dakota on Thursday. ...Northeast... A shortwave trough currently over western Ontario will track southeastward across the Great Lakes on Thursday. Increasing large scale forcing will overspread parts of PA/NY and New England through the day, promoting afternoon thunderstorm development along an approaching cold front. A warm/humid air mass will be present ahead of the front, with steep low-level lapse rates and sufficient CAPE to pose a risk of damaging wind gusts and perhaps some hail. Given trends in 12z model guidance regarding thunderstorm coverage, have added a SLGT risk for portions of the region. ...ND... A prominent mid-level ridge will be established over the central US tomorrow. Model guidance suggests a subtle shortwave trough will track into eastern MT during the afternoon and top the ridge overnight. Southerly low-level winds will help to draw moisture northward into ND by late afternoon, resulting in a reservoir of strong instability. Thunderstorms are expected to develop over western ND posing a risk of large hail and damaging winds. Several 12z HREF members suggest the risk of upscale growth and a bowing MCS tracking eastward across ND overnight. ...Upper MS Valley... A weak/diffuse low-level baroclinic zone will extend from southeast MN into IL on Thursday. Strengthening southwesterly low-level winds will enhance warm advection by early evening, leading to scattered thunderstorms. A few of these storms could be strong, posing a risk of gusty winds and hail. ..Hart.. 07/02/2025 Read more

851
ABPZ20 KNHC 021714
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Wed Jul 2 2025

For the eastern and central North Pacific east of 180 longitude:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Flossie, located in the eastern Pacific basin, a few hundred miles
south of the southern tip of the Baja California peninsula.

South of Southwestern Mexico:
An area of low pressure is forecast to develop several hundred miles
offshore of southwestern Mexico in a few days. Environmental
conditions appear conducive for some gradual development of this
system thereafter, and a tropical depression could form over the
weekend or early next week while it moves generally
west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Kelly

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Wed Jul 02 2025 Valid 021700Z - 031200Z ...Nevada... Anomalously high precipitable water values, including observed an observed value of nearly 1 inch from the 1200Z Las Vegas sounding, suggests higher precipitation efficiency from expected showers and thunderstorms moving into southern Nevada today. This will limit dry lightning ignition efficiency across southern Nevada. A relatively dry sub-cloud layer remains in place across central and northern Nevada, where initially high-based shower and thunderstorm development is expected through the day, increasing potential for ignition over dry fuels denoted by a general northward shift in Isolated Dry Thunderstorm highlights. ...Far Northeastern California into southeastern Oregon... Stronger mid-level winds and accelerated northeast thunderstorm motions owing to an encroaching mid-level trough into the Pacific Northwest will limit precipitation and increase ignition likelihood amid drier fuels across northeastern California into southeastern Oregon this afternoon. Isolated Dry Thunderstorm highlights were added to reflect this threat for today. ..Williams.. 07/02/2025 .PREV DISCUSSION... /ISSUED 0225 AM CDT Wed Jul 02 2025/ ...Synopsis... Mid-level troughing is forecast to slowly progress across central CA today, while another trough moves onshore across WA. Decreasing heights over the Northwest will continue to provide southerly transport of monsoon moisture into portions of the Great Basin and Intermountain West, where numerous thunderstorms are likely. Dry and breezy conditions will also be likely over the Cascades and western Columbia Basin. ...Lee of the Cascades... Increasing flow aloft ahead of the Pacific trough will favor dry downslope winds across the Cascades and western Columbia Basin. With daytime temperatures well into the 90s F, deep mixing will promote low boundary layer RH of 15-20%. With downslope winds of 15-25 mph, widespread elevated fire-weather conditions are likely on the lee slopes and through the gaps of the higher terrain. Some localized critical conditions are also possible where the terrain-enhanced winds and locally drier conditions may develop for a few hours this afternoon. ...Great Basin and northern Rockies Dry Thunder... East of the upper low, widespread thunderstorm activity is expected across the Great Basin and western slopes of the Rockies. A monsoon surge of 0.8 to 1.0 inch PWATs will lift northward across central/eastern NV into UT and western CO/WY. Weak ascent from the trough, along with diurnal heating of the terrain will result in scattered to numerous high-based showers and thunderstorms by early afternoon. Additional storms are likely along a cold front across ID and western MT. Given the increasing moisture content and continued southerly flow, some wetting rainfall is expected from training rounds of thunderstorms. A mix of wet and dry thunderstorms will support potential lightning ignitions, particularly with fast moving cells and on the edges of the most intense downdraft cores. This appears most likely across parts of eastern UT and western CO where less wetting rainfall is expected. Though isolated dry strikes are possible over the entire IsoDryT area. ...Northern OR/Southern CA... Scattered thunderstorms are again expected ahead of the upper low. A few of these storms may be drier with 30+ kt of southerly flow and relatively deeply mixed boundary layers. While a few dry strikes are possible outside of the heavier cores, recent QPE estimates of 0.5 to 1 inches indicate area fuels have likely been tempered to some degree. This suggests the threat for dry lightning is below IsoDryT thresholds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Wed Jul 02 2025 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTH-CENTRAL MONTANA... ...SUMMARY... Scattered severe thunderstorm gusts are possible across Montana this afternoon into the evening. Isolated severe thunderstorms may occur today across parts of the Great Basin and Upper Midwest/Great Lakes. ...Northern Rockies into the Northern High Plains... Recent satellite imagery shows expansive upper ridging extending from the southern Plains into central AB/SK. An upper low is slowly drifting eastward into southern CA, impinging on the western periphery of this upper ridging. This upper low is forecast to stay well south of the region throughout the day, but a modest vorticity maximum, generated by convection east of this upper low, is forecast to move into the northern Rockies this afternoon. Ascent associated with this vorticity max coupled with orographic ascent, and perhaps additional large-scale ascent ahead of weak shortwave trough moving across OR, is expected to result in thunderstorms over the high terrain as the airmass diurnally destabilizes this afternoon. Persistent southwesterly flow aloft will then take these storms north/northeastward into more of the MT High Plains. Highest storm coverage is expected from central ID into western MT during the afternoon, before transition to more of central MT this evening. Vertical shear is strong enough for occasionally organized storm structures. The high cloud bases and steep low-level lapse rates will contribute to the potential for strong to severe wind gusts, particularly across central MT as storms become outflow dominant. ...Western Great Basin... Increasing thunderstorm coverage is anticipated this afternoon and evening east of a slow-moving upper low currently moving into central/southern CA. Moderate mid-level flow through the eastern periphery of the upper low combined with modest buoyancy and high LCLs will result in an environment favorable to isolated to scattered strong to severe wind gusts. Highest overall thunderstorm coverage and relatively greater chance for strong/severe gusts is over southern NV. ...AZ... 12Z PHX sounding sampled a precipitable water of 1.4" this morning and the expectation is that this moisture will support the development of numerous thunderstorms across the region this afternoon/evening. Development is anticipated over the higher terrain first, before then slowly moving westward toward lower elevations. This overall pattern generally favors strong to severe gusts across central AZ. However, very weak mid-level flow suggests the westward push off the terrain will be slow, if it occurs at all, which should limit the overall severe potential. ...Upper Midwest/Great Lakes... A weak cold front is forecast to move into northern MN, northern WI, Upper MI this afternoon. Thunderstorms are anticipated along this front as it interacts with the modest buoyancy (i.e. MLCAPE around 1000 J/kg) over this region. Isolated pre-frontal storms are possible across Lower MI as well. Moderate mid-level flow will support the potential for damaging gusts with any of the stronger storms. Additional thunderstorms are possible later this evening farther west from far southeast SD into southern MN and northern IA. There is some chance development occurs along the front during the afternoon, but low-level convergence will likely be too weak to overcome the convective inhibition. Later, isolated coverage appears more likely as warm-air advection, supported by modest low-level jet, increases. Given the expected combination of buoyancy and vertical shear, one or two more organized storms capable of large hail are possible. ...Eastern NC... Weak upper troughing and attendant surface cold front will advance eastward today across the southern Mid-Atlantic and Carolinas. Widespread thunderstorm development is anticipated ahead of these features. However, poor lapse rates aloft will likely limit updraft strength, with deep-layer shear limiting storm organization as well. A few water-loaded downbursts are possible within the strongest storms. ..Mosier/Karstens.. 07/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Wed Jul 02 2025 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTH-CENTRAL MONTANA... ...SUMMARY... Scattered severe thunderstorm gusts are possible across Montana this afternoon into the evening. Isolated severe thunderstorms may occur today across parts of the Great Basin and Upper Midwest/Great Lakes. ...Northern Rockies into the Northern High Plains... Recent satellite imagery shows expansive upper ridging extending from the southern Plains into central AB/SK. An upper low is slowly drifting eastward into southern CA, impinging on the western periphery of this upper ridging. This upper low is forecast to stay well south of the region throughout the day, but a modest vorticity maximum, generated by convection east of this upper low, is forecast to move into the northern Rockies this afternoon. Ascent associated with this vorticity max coupled with orographic ascent, and perhaps additional large-scale ascent ahead of weak shortwave trough moving across OR, is expected to result in thunderstorms over the high terrain as the airmass diurnally destabilizes this afternoon. Persistent southwesterly flow aloft will then take these storms north/northeastward into more of the MT High Plains. Highest storm coverage is expected from central ID into western MT during the afternoon, before transition to more of central MT this evening. Vertical shear is strong enough for occasionally organized storm structures. The high cloud bases and steep low-level lapse rates will contribute to the potential for strong to severe wind gusts, particularly across central MT as storms become outflow dominant. ...Western Great Basin... Increasing thunderstorm coverage is anticipated this afternoon and evening east of a slow-moving upper low currently moving into central/southern CA. Moderate mid-level flow through the eastern periphery of the upper low combined with modest buoyancy and high LCLs will result in an environment favorable to isolated to scattered strong to severe wind gusts. Highest overall thunderstorm coverage and relatively greater chance for strong/severe gusts is over southern NV. ...AZ... 12Z PHX sounding sampled a precipitable water of 1.4" this morning and the expectation is that this moisture will support the development of numerous thunderstorms across the region this afternoon/evening. Development is anticipated over the higher terrain first, before then slowly moving westward toward lower elevations. This overall pattern generally favors strong to severe gusts across central AZ. However, very weak mid-level flow suggests the westward push off the terrain will be slow, if it occurs at all, which should limit the overall severe potential. ...Upper Midwest/Great Lakes... A weak cold front is forecast to move into northern MN, northern WI, Upper MI this afternoon. Thunderstorms are anticipated along this front as it interacts with the modest buoyancy (i.e. MLCAPE around 1000 J/kg) over this region. Isolated pre-frontal storms are possible across Lower MI as well. Moderate mid-level flow will support the potential for damaging gusts with any of the stronger storms. Additional thunderstorms are possible later this evening farther west from far southeast SD into southern MN and northern IA. There is some chance development occurs along the front during the afternoon, but low-level convergence will likely be too weak to overcome the convective inhibition. Later, isolated coverage appears more likely as warm-air advection, supported by modest low-level jet, increases. Given the expected combination of buoyancy and vertical shear, one or two more organized storms capable of large hail are possible. ...Eastern NC... Weak upper troughing and attendant surface cold front will advance eastward today across the southern Mid-Atlantic and Carolinas. Widespread thunderstorm development is anticipated ahead of these features. However, poor lapse rates aloft will likely limit updraft strength, with deep-layer shear limiting storm organization as well. A few water-loaded downbursts are possible within the strongest storms. ..Mosier/Karstens.. 07/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Wed Jul 02 2025 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTH-CENTRAL MONTANA... ...SUMMARY... Scattered severe thunderstorm gusts are possible across Montana this afternoon into the evening. Isolated severe thunderstorms may occur today across parts of the Great Basin and Upper Midwest/Great Lakes. ...Northern Rockies into the Northern High Plains... Recent satellite imagery shows expansive upper ridging extending from the southern Plains into central AB/SK. An upper low is slowly drifting eastward into southern CA, impinging on the western periphery of this upper ridging. This upper low is forecast to stay well south of the region throughout the day, but a modest vorticity maximum, generated by convection east of this upper low, is forecast to move into the northern Rockies this afternoon. Ascent associated with this vorticity max coupled with orographic ascent, and perhaps additional large-scale ascent ahead of weak shortwave trough moving across OR, is expected to result in thunderstorms over the high terrain as the airmass diurnally destabilizes this afternoon. Persistent southwesterly flow aloft will then take these storms north/northeastward into more of the MT High Plains. Highest storm coverage is expected from central ID into western MT during the afternoon, before transition to more of central MT this evening. Vertical shear is strong enough for occasionally organized storm structures. The high cloud bases and steep low-level lapse rates will contribute to the potential for strong to severe wind gusts, particularly across central MT as storms become outflow dominant. ...Western Great Basin... Increasing thunderstorm coverage is anticipated this afternoon and evening east of a slow-moving upper low currently moving into central/southern CA. Moderate mid-level flow through the eastern periphery of the upper low combined with modest buoyancy and high LCLs will result in an environment favorable to isolated to scattered strong to severe wind gusts. Highest overall thunderstorm coverage and relatively greater chance for strong/severe gusts is over southern NV. ...AZ... 12Z PHX sounding sampled a precipitable water of 1.4" this morning and the expectation is that this moisture will support the development of numerous thunderstorms across the region this afternoon/evening. Development is anticipated over the higher terrain first, before then slowly moving westward toward lower elevations. This overall pattern generally favors strong to severe gusts across central AZ. However, very weak mid-level flow suggests the westward push off the terrain will be slow, if it occurs at all, which should limit the overall severe potential. ...Upper Midwest/Great Lakes... A weak cold front is forecast to move into northern MN, northern WI, Upper MI this afternoon. Thunderstorms are anticipated along this front as it interacts with the modest buoyancy (i.e. MLCAPE around 1000 J/kg) over this region. Isolated pre-frontal storms are possible across Lower MI as well. Moderate mid-level flow will support the potential for damaging gusts with any of the stronger storms. Additional thunderstorms are possible later this evening farther west from far southeast SD into southern MN and northern IA. There is some chance development occurs along the front during the afternoon, but low-level convergence will likely be too weak to overcome the convective inhibition. Later, isolated coverage appears more likely as warm-air advection, supported by modest low-level jet, increases. Given the expected combination of buoyancy and vertical shear, one or two more organized storms capable of large hail are possible. ...Eastern NC... Weak upper troughing and attendant surface cold front will advance eastward today across the southern Mid-Atlantic and Carolinas. Widespread thunderstorm development is anticipated ahead of these features. However, poor lapse rates aloft will likely limit updraft strength, with deep-layer shear limiting storm organization as well. A few water-loaded downbursts are possible within the strongest storms. ..Mosier/Karstens.. 07/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Wed Jul 02 2025 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTH-CENTRAL MONTANA... ...SUMMARY... Scattered severe thunderstorm gusts are possible across Montana this afternoon into the evening. Isolated severe thunderstorms may occur today across parts of the Great Basin and Upper Midwest/Great Lakes. ...Northern Rockies into the Northern High Plains... Recent satellite imagery shows expansive upper ridging extending from the southern Plains into central AB/SK. An upper low is slowly drifting eastward into southern CA, impinging on the western periphery of this upper ridging. This upper low is forecast to stay well south of the region throughout the day, but a modest vorticity maximum, generated by convection east of this upper low, is forecast to move into the northern Rockies this afternoon. Ascent associated with this vorticity max coupled with orographic ascent, and perhaps additional large-scale ascent ahead of weak shortwave trough moving across OR, is expected to result in thunderstorms over the high terrain as the airmass diurnally destabilizes this afternoon. Persistent southwesterly flow aloft will then take these storms north/northeastward into more of the MT High Plains. Highest storm coverage is expected from central ID into western MT during the afternoon, before transition to more of central MT this evening. Vertical shear is strong enough for occasionally organized storm structures. The high cloud bases and steep low-level lapse rates will contribute to the potential for strong to severe wind gusts, particularly across central MT as storms become outflow dominant. ...Western Great Basin... Increasing thunderstorm coverage is anticipated this afternoon and evening east of a slow-moving upper low currently moving into central/southern CA. Moderate mid-level flow through the eastern periphery of the upper low combined with modest buoyancy and high LCLs will result in an environment favorable to isolated to scattered strong to severe wind gusts. Highest overall thunderstorm coverage and relatively greater chance for strong/severe gusts is over southern NV. ...AZ... 12Z PHX sounding sampled a precipitable water of 1.4" this morning and the expectation is that this moisture will support the development of numerous thunderstorms across the region this afternoon/evening. Development is anticipated over the higher terrain first, before then slowly moving westward toward lower elevations. This overall pattern generally favors strong to severe gusts across central AZ. However, very weak mid-level flow suggests the westward push off the terrain will be slow, if it occurs at all, which should limit the overall severe potential. ...Upper Midwest/Great Lakes... A weak cold front is forecast to move into northern MN, northern WI, Upper MI this afternoon. Thunderstorms are anticipated along this front as it interacts with the modest buoyancy (i.e. MLCAPE around 1000 J/kg) over this region. Isolated pre-frontal storms are possible across Lower MI as well. Moderate mid-level flow will support the potential for damaging gusts with any of the stronger storms. Additional thunderstorms are possible later this evening farther west from far southeast SD into southern MN and northern IA. There is some chance development occurs along the front during the afternoon, but low-level convergence will likely be too weak to overcome the convective inhibition. Later, isolated coverage appears more likely as warm-air advection, supported by modest low-level jet, increases. Given the expected combination of buoyancy and vertical shear, one or two more organized storms capable of large hail are possible. ...Eastern NC... Weak upper troughing and attendant surface cold front will advance eastward today across the southern Mid-Atlantic and Carolinas. Widespread thunderstorm development is anticipated ahead of these features. However, poor lapse rates aloft will likely limit updraft strength, with deep-layer shear limiting storm organization as well. A few water-loaded downbursts are possible within the strongest storms. ..Mosier/Karstens.. 07/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Wed Jul 02 2025 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTH-CENTRAL MONTANA... ...SUMMARY... Scattered severe thunderstorm gusts are possible across Montana this afternoon into the evening. Isolated severe thunderstorms may occur today across parts of the Great Basin and Upper Midwest/Great Lakes. ...Northern Rockies into the Northern High Plains... Recent satellite imagery shows expansive upper ridging extending from the southern Plains into central AB/SK. An upper low is slowly drifting eastward into southern CA, impinging on the western periphery of this upper ridging. This upper low is forecast to stay well south of the region throughout the day, but a modest vorticity maximum, generated by convection east of this upper low, is forecast to move into the northern Rockies this afternoon. Ascent associated with this vorticity max coupled with orographic ascent, and perhaps additional large-scale ascent ahead of weak shortwave trough moving across OR, is expected to result in thunderstorms over the high terrain as the airmass diurnally destabilizes this afternoon. Persistent southwesterly flow aloft will then take these storms north/northeastward into more of the MT High Plains. Highest storm coverage is expected from central ID into western MT during the afternoon, before transition to more of central MT this evening. Vertical shear is strong enough for occasionally organized storm structures. The high cloud bases and steep low-level lapse rates will contribute to the potential for strong to severe wind gusts, particularly across central MT as storms become outflow dominant. ...Western Great Basin... Increasing thunderstorm coverage is anticipated this afternoon and evening east of a slow-moving upper low currently moving into central/southern CA. Moderate mid-level flow through the eastern periphery of the upper low combined with modest buoyancy and high LCLs will result in an environment favorable to isolated to scattered strong to severe wind gusts. Highest overall thunderstorm coverage and relatively greater chance for strong/severe gusts is over southern NV. ...AZ... 12Z PHX sounding sampled a precipitable water of 1.4" this morning and the expectation is that this moisture will support the development of numerous thunderstorms across the region this afternoon/evening. Development is anticipated over the higher terrain first, before then slowly moving westward toward lower elevations. This overall pattern generally favors strong to severe gusts across central AZ. However, very weak mid-level flow suggests the westward push off the terrain will be slow, if it occurs at all, which should limit the overall severe potential. ...Upper Midwest/Great Lakes... A weak cold front is forecast to move into northern MN, northern WI, Upper MI this afternoon. Thunderstorms are anticipated along this front as it interacts with the modest buoyancy (i.e. MLCAPE around 1000 J/kg) over this region. Isolated pre-frontal storms are possible across Lower MI as well. Moderate mid-level flow will support the potential for damaging gusts with any of the stronger storms. Additional thunderstorms are possible later this evening farther west from far southeast SD into southern MN and northern IA. There is some chance development occurs along the front during the afternoon, but low-level convergence will likely be too weak to overcome the convective inhibition. Later, isolated coverage appears more likely as warm-air advection, supported by modest low-level jet, increases. Given the expected combination of buoyancy and vertical shear, one or two more organized storms capable of large hail are possible. ...Eastern NC... Weak upper troughing and attendant surface cold front will advance eastward today across the southern Mid-Atlantic and Carolinas. Widespread thunderstorm development is anticipated ahead of these features. However, poor lapse rates aloft will likely limit updraft strength, with deep-layer shear limiting storm organization as well. A few water-loaded downbursts are possible within the strongest storms. ..Mosier/Karstens.. 07/02/2025 Read more