Aggregator

WW 594 SEVERE TSTM KS 180125Z - 180800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 594 NWS Storm Prediction Center Norman OK 825 PM CDT Sat Aug 17 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Kansas * Effective this Saturday night and Sunday morning from 825 PM until 300 AM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2 inches in diameter possible SUMMARY...A small but well-organized cluster of storms across northwest Kansas early this evening will continue east-southeastward with additional storms expected to develop near/ahead of it through late evening. Large hail and locally damaging winds can initially be expected with this activity, with a more certain potential for damaging winds given the possibility of an expanding/organizing linear cluster across central Kansas. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 35 miles south southwest of Hill City KS to 35 miles south southeast of Manhattan KS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 590...WW 592...WW 593... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 29025. ...Guyer Read more

MD 1783 CONCERNING SEVERE THUNDERSTORM WATCH 594...595... FOR KANSAS...NORTHEAST OKLAHOMA...SOUTHWEST MISSOURI...AND EXTREME NORTHWEST ARKANSAS
Mesoscale Discussion 1783 NWS Storm Prediction Center Norman OK 0142 AM CDT Sun Aug 18 2019 Areas affected...Kansas...northeast Oklahoma...southwest Missouri...and extreme northwest Arkansas Concerning...Severe Thunderstorm Watch 594...595... Valid 180642Z - 180815Z The severe weather threat for Severe Thunderstorm Watch 594, 595 continues. SUMMARY...Thunderstorms continue across much of Kansas this morning. The leading edge of the thunderstorms continues to push toward northeast Oklahoma and southwest Missouri. Gusty thunderstorm winds and hail will be the primary severe threat with these storms. A new watch is being considered for portions of northeast Oklahoma and southwest Missouri. DISCUSSION...Another round of thunderstorms is ongoing across much of Kansas this morning. The convection has organized itself into another "bow and arrow" mesoscale convective system (MCS). The leading edge of this MCS (the bow) is quickly moving southeast toward far southeast Kansas, northeast Oklahoma, and southwest Missouri. The environment along and ahead of this bow is characterized by deep-layer shear on the order of 40 knots and most-unstable CAPE values around 2000-2500 J/kg. Additionally, mixed-layer convective inhibition actually weakens the farther east this MCS moves. Thus a continuation of severe potential in areas outside of Severe Thunderstorm Watch #594 is possible. As such, a new watch is being considered. Upstream from the bow, the "arrow" thunderstorms across central Kansas will continue within a moderately unstable and sufficiently sheared airmass to continue the potential for hail and gusty winds for at least another few hours. Therefore an extension in time of Severe Thunderstorm Watch #584 may be needed. ..Marsh.. 08/18/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SGF...EAX...TSA...TOP...ICT... LAT...LON 37339724 38569607 37429348 36099474 37339724 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0129 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... Upper-level ridging will continue to strengthen and amplify over the western CONUS tomorrow. Much of the Intermountain West will remain hot/dry, and large-scale flow will be relatively weak across the region. A weak mid-level shortwave trough is forecast to move over the northern Rockies during the day, which could help initiate isolated dry thunderstorms across southwest Montana/vicinity. However, with heights generally rising across the region and forecast relatively dry (precipitable water values of 0.4-0.6") and stable conditions (ML/MUCAPE < 250 J/kg) conditions, an area was not introduced. ..Nauslar.. 08/18/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0129 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... Upper-level ridging will continue to strengthen and amplify over the western CONUS tomorrow. Much of the Intermountain West will remain hot/dry, and large-scale flow will be relatively weak across the region. A weak mid-level shortwave trough is forecast to move over the northern Rockies during the day, which could help initiate isolated dry thunderstorms across southwest Montana/vicinity. However, with heights generally rising across the region and forecast relatively dry (precipitable water values of 0.4-0.6") and stable conditions (ML/MUCAPE < 250 J/kg) conditions, an area was not introduced. ..Nauslar.. 08/18/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0129 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... Upper-level ridging will continue to strengthen and amplify over the western CONUS tomorrow. Much of the Intermountain West will remain hot/dry, and large-scale flow will be relatively weak across the region. A weak mid-level shortwave trough is forecast to move over the northern Rockies during the day, which could help initiate isolated dry thunderstorms across southwest Montana/vicinity. However, with heights generally rising across the region and forecast relatively dry (precipitable water values of 0.4-0.6") and stable conditions (ML/MUCAPE < 250 J/kg) conditions, an area was not introduced. ..Nauslar.. 08/18/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0129 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... Upper-level ridging will continue to strengthen and amplify over the western CONUS tomorrow. Much of the Intermountain West will remain hot/dry, and large-scale flow will be relatively weak across the region. A weak mid-level shortwave trough is forecast to move over the northern Rockies during the day, which could help initiate isolated dry thunderstorms across southwest Montana/vicinity. However, with heights generally rising across the region and forecast relatively dry (precipitable water values of 0.4-0.6") and stable conditions (ML/MUCAPE < 250 J/kg) conditions, an area was not introduced. ..Nauslar.. 08/18/2019 ...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 0116 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...Synopsis... Upper-level ridging will amplify over the western CONUS as an upper-level shortwave trough moves over the northern Plains and Great Lakes. Mid-level 25-50 knot westerly flow will remain over the northern Intermountain West with hot/dry conditions across much of the Intermountain West. Elevated conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%) will develop from southern Idaho into southern/central Wyoming and northwest Colorado/northeast Utah this afternoon/evening. This is the fourth consecutive day of dry/windy conditions across this area, which will continue to cure fuels with ERCs now mostly in the 70-90th percentiles. Locally elevated conditions (southerly winds of 10-20 mph, RH values of 8-15%) are likely to develop this afternoon/evening across northwest Arizona into southeast Nevada/southwest Utah. While these conditions are relatively common for this area and time of year, dry fuels and ongoing fire activity in the area warranted a mention. ..Nauslar.. 08/18/2019 ...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 0116 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...Synopsis... Upper-level ridging will amplify over the western CONUS as an upper-level shortwave trough moves over the northern Plains and Great Lakes. Mid-level 25-50 knot westerly flow will remain over the northern Intermountain West with hot/dry conditions across much of the Intermountain West. Elevated conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%) will develop from southern Idaho into southern/central Wyoming and northwest Colorado/northeast Utah this afternoon/evening. This is the fourth consecutive day of dry/windy conditions across this area, which will continue to cure fuels with ERCs now mostly in the 70-90th percentiles. Locally elevated conditions (southerly winds of 10-20 mph, RH values of 8-15%) are likely to develop this afternoon/evening across northwest Arizona into southeast Nevada/southwest Utah. While these conditions are relatively common for this area and time of year, dry fuels and ongoing fire activity in the area warranted a mention. ..Nauslar.. 08/18/2019 ...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 0116 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...Synopsis... Upper-level ridging will amplify over the western CONUS as an upper-level shortwave trough moves over the northern Plains and Great Lakes. Mid-level 25-50 knot westerly flow will remain over the northern Intermountain West with hot/dry conditions across much of the Intermountain West. Elevated conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%) will develop from southern Idaho into southern/central Wyoming and northwest Colorado/northeast Utah this afternoon/evening. This is the fourth consecutive day of dry/windy conditions across this area, which will continue to cure fuels with ERCs now mostly in the 70-90th percentiles. Locally elevated conditions (southerly winds of 10-20 mph, RH values of 8-15%) are likely to develop this afternoon/evening across northwest Arizona into southeast Nevada/southwest Utah. While these conditions are relatively common for this area and time of year, dry fuels and ongoing fire activity in the area warranted a mention. ..Nauslar.. 08/18/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1200 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis... A negative-tilt shortwave trough will quickly eject northeast across Quebec, resulting in rising heights over the Great Lakes during the day. A brief period of lift will occur over northern parts of the northeastern states, where weak instability will develop. Overnight and to the west, subtle height falls will occur over the northern Plains and Upper MS Valley, on the southern fringe of a shortwave trough over MB. Here, a cold front will move into the central Dakotas by 00Z, with mid 60s F dewpoints spreading northward ahead of it aiding destabilization and supporting at least isolated storms. To the south, strong instability will once again develop over the central Plains, but will be capped for most of the period. ...Northern Plains... Strong heating will occur over ND, northern MN, and western SD along and west of the wind shift. The air mass over the moist sector will be capped for much of the day, but a narrow zone of uncapped air should develop along the front. Isolated late afternoon and evening storms are possible with marginal wind or hail. Overnight, elevated instability will develop from NE/IA into MN, and sporadic storms cannot be ruled out from northeast KS into IA. However, the probability of severe in those areas appears low prior to 12Z Tuesday. ...Northern NY into ME... Low-level winds will continue to veer during the day as the shortwave trough ejects east/northeast over the region. Forecast soundings show sufficient instability for thunderstorms during the day, and modest deep shear, but midlevel subsidence will likely mitigate overall storm coverage and intensity. As such, severe weather is not currently forecast, but a few strong storms cannot be ruled out with gusty winds and small hail. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/18/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1200 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis... A negative-tilt shortwave trough will quickly eject northeast across Quebec, resulting in rising heights over the Great Lakes during the day. A brief period of lift will occur over northern parts of the northeastern states, where weak instability will develop. Overnight and to the west, subtle height falls will occur over the northern Plains and Upper MS Valley, on the southern fringe of a shortwave trough over MB. Here, a cold front will move into the central Dakotas by 00Z, with mid 60s F dewpoints spreading northward ahead of it aiding destabilization and supporting at least isolated storms. To the south, strong instability will once again develop over the central Plains, but will be capped for most of the period. ...Northern Plains... Strong heating will occur over ND, northern MN, and western SD along and west of the wind shift. The air mass over the moist sector will be capped for much of the day, but a narrow zone of uncapped air should develop along the front. Isolated late afternoon and evening storms are possible with marginal wind or hail. Overnight, elevated instability will develop from NE/IA into MN, and sporadic storms cannot be ruled out from northeast KS into IA. However, the probability of severe in those areas appears low prior to 12Z Tuesday. ...Northern NY into ME... Low-level winds will continue to veer during the day as the shortwave trough ejects east/northeast over the region. Forecast soundings show sufficient instability for thunderstorms during the day, and modest deep shear, but midlevel subsidence will likely mitigate overall storm coverage and intensity. As such, severe weather is not currently forecast, but a few strong storms cannot be ruled out with gusty winds and small hail. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/18/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1200 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis... A negative-tilt shortwave trough will quickly eject northeast across Quebec, resulting in rising heights over the Great Lakes during the day. A brief period of lift will occur over northern parts of the northeastern states, where weak instability will develop. Overnight and to the west, subtle height falls will occur over the northern Plains and Upper MS Valley, on the southern fringe of a shortwave trough over MB. Here, a cold front will move into the central Dakotas by 00Z, with mid 60s F dewpoints spreading northward ahead of it aiding destabilization and supporting at least isolated storms. To the south, strong instability will once again develop over the central Plains, but will be capped for most of the period. ...Northern Plains... Strong heating will occur over ND, northern MN, and western SD along and west of the wind shift. The air mass over the moist sector will be capped for much of the day, but a narrow zone of uncapped air should develop along the front. Isolated late afternoon and evening storms are possible with marginal wind or hail. Overnight, elevated instability will develop from NE/IA into MN, and sporadic storms cannot be ruled out from northeast KS into IA. However, the probability of severe in those areas appears low prior to 12Z Tuesday. ...Northern NY into ME... Low-level winds will continue to veer during the day as the shortwave trough ejects east/northeast over the region. Forecast soundings show sufficient instability for thunderstorms during the day, and modest deep shear, but midlevel subsidence will likely mitigate overall storm coverage and intensity. As such, severe weather is not currently forecast, but a few strong storms cannot be ruled out with gusty winds and small hail. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/18/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1200 AM CDT Sun Aug 18 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe storms are possible over parts of the northern Plains Monday evening and overnight. ...Synopsis... A negative-tilt shortwave trough will quickly eject northeast across Quebec, resulting in rising heights over the Great Lakes during the day. A brief period of lift will occur over northern parts of the northeastern states, where weak instability will develop. Overnight and to the west, subtle height falls will occur over the northern Plains and Upper MS Valley, on the southern fringe of a shortwave trough over MB. Here, a cold front will move into the central Dakotas by 00Z, with mid 60s F dewpoints spreading northward ahead of it aiding destabilization and supporting at least isolated storms. To the south, strong instability will once again develop over the central Plains, but will be capped for most of the period. ...Northern Plains... Strong heating will occur over ND, northern MN, and western SD along and west of the wind shift. The air mass over the moist sector will be capped for much of the day, but a narrow zone of uncapped air should develop along the front. Isolated late afternoon and evening storms are possible with marginal wind or hail. Overnight, elevated instability will develop from NE/IA into MN, and sporadic storms cannot be ruled out from northeast KS into IA. However, the probability of severe in those areas appears low prior to 12Z Tuesday. ...Northern NY into ME... Low-level winds will continue to veer during the day as the shortwave trough ejects east/northeast over the region. Forecast soundings show sufficient instability for thunderstorms during the day, and modest deep shear, but midlevel subsidence will likely mitigate overall storm coverage and intensity. As such, severe weather is not currently forecast, but a few strong storms cannot be ruled out with gusty winds and small hail. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/18/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER LOWER MI...NORTHEAST IN...AND FAR NORTHWEST OH... ...SUMMARY... Scattered thunderstorms capable of severe gusts and large hail are possible over Lower Michigan, northeast Indiana, and far northwest Ohio this afternoon into the early evening. ...Middle MS Valley through OH Valley and Upper Great Lakes... Well-organized MCS currently moving through southern MN and northern IA will likely be in the vicinity of the IA/IL border at the beginning of the period. The resulting convectively induced vorticity maximum and attendant isolated showers and thunderstorms are expected to gradually move eastward this morning. A very moist and diurnally destabilized air mass is expected downstream across Lower MI and the OH Valley. As a result, thunderstorms associated with this vorticity maximum are expected to reintensify as they move into Lower MI and the middle OH Valley this afternoon. The anticipated trajectory of vorticity maximum currently takes it over Lower MI during the afternoon. Enhanced mid-level flow will accompany this vorticity maximum, resulting in strong enough vertical shear to support more organized storm structures capable of damaging wind gusts and isolated hail. Highest concentration of severe storms is currently expected to be across southern portions of Lower MI and adjacent northeast IN and northwest OH. Another round of thunderstorms is possible over the region as the cold front moves through this evening, but development of these storms is largely dependent on the strength of the antecedent storms and air mass recovery in their wake. ...Lower Great Lakes into the Northeast... Low-amplitude shortwave trough currently moving through the middle OH Valley will continue eastward/northeastward, reaching the Lower Great Lakes/Northeast region by the early afternoon. Despite relatively modest lapse rates, surface dewpoints in the upper 60s (isolated low 70s possible) and surface temperatures in the mid 80s will still support moderate buoyancy capable of occasionally strong updrafts. Vertical shear will be modest and a predominantly linear multicell mode is anticipated. Water-loaded downbursts are possible with strongest storms. ...Ozark Plateau into OK... A very warm and moist low-level air mass will remain in place across the region with afternoon dewpoints in the 70s and temperatures in the upper 90s/low 100s. Steep mid-level lapse rates atop this warm and moist air mass will result in very strong buoyancy (i.e. MLCAPE greater than 3000 J/kg) but also modest convective inhibition. Impetus for overcoming this convective inhibition and initiating deep updrafts is expected to be the cold front moving south through the region. However, location of the cold front this afternoon is uncertain, primarily because of potential modification of its position as a result of outflow from the ongoing MCS across KS. There is also some chance for the MCS to remain over northeast OK and the Ozark Plateau long enough to prevent air mass recovery. These uncertainties merit keeping Marginal severe probabilities for this forecast, but an upgrade may be needed in a subsequent outlook as these mesoscale details become more certain. ..Mosier/Nauslar.. 08/18/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER LOWER MI...NORTHEAST IN...AND FAR NORTHWEST OH... ...SUMMARY... Scattered thunderstorms capable of severe gusts and large hail are possible over Lower Michigan, northeast Indiana, and far northwest Ohio this afternoon into the early evening. ...Middle MS Valley through OH Valley and Upper Great Lakes... Well-organized MCS currently moving through southern MN and northern IA will likely be in the vicinity of the IA/IL border at the beginning of the period. The resulting convectively induced vorticity maximum and attendant isolated showers and thunderstorms are expected to gradually move eastward this morning. A very moist and diurnally destabilized air mass is expected downstream across Lower MI and the OH Valley. As a result, thunderstorms associated with this vorticity maximum are expected to reintensify as they move into Lower MI and the middle OH Valley this afternoon. The anticipated trajectory of vorticity maximum currently takes it over Lower MI during the afternoon. Enhanced mid-level flow will accompany this vorticity maximum, resulting in strong enough vertical shear to support more organized storm structures capable of damaging wind gusts and isolated hail. Highest concentration of severe storms is currently expected to be across southern portions of Lower MI and adjacent northeast IN and northwest OH. Another round of thunderstorms is possible over the region as the cold front moves through this evening, but development of these storms is largely dependent on the strength of the antecedent storms and air mass recovery in their wake. ...Lower Great Lakes into the Northeast... Low-amplitude shortwave trough currently moving through the middle OH Valley will continue eastward/northeastward, reaching the Lower Great Lakes/Northeast region by the early afternoon. Despite relatively modest lapse rates, surface dewpoints in the upper 60s (isolated low 70s possible) and surface temperatures in the mid 80s will still support moderate buoyancy capable of occasionally strong updrafts. Vertical shear will be modest and a predominantly linear multicell mode is anticipated. Water-loaded downbursts are possible with strongest storms. ...Ozark Plateau into OK... A very warm and moist low-level air mass will remain in place across the region with afternoon dewpoints in the 70s and temperatures in the upper 90s/low 100s. Steep mid-level lapse rates atop this warm and moist air mass will result in very strong buoyancy (i.e. MLCAPE greater than 3000 J/kg) but also modest convective inhibition. Impetus for overcoming this convective inhibition and initiating deep updrafts is expected to be the cold front moving south through the region. However, location of the cold front this afternoon is uncertain, primarily because of potential modification of its position as a result of outflow from the ongoing MCS across KS. There is also some chance for the MCS to remain over northeast OK and the Ozark Plateau long enough to prevent air mass recovery. These uncertainties merit keeping Marginal severe probabilities for this forecast, but an upgrade may be needed in a subsequent outlook as these mesoscale details become more certain. ..Mosier/Nauslar.. 08/18/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER LOWER MI...NORTHEAST IN...AND FAR NORTHWEST OH... ...SUMMARY... Scattered thunderstorms capable of severe gusts and large hail are possible over Lower Michigan, northeast Indiana, and far northwest Ohio this afternoon into the early evening. ...Middle MS Valley through OH Valley and Upper Great Lakes... Well-organized MCS currently moving through southern MN and northern IA will likely be in the vicinity of the IA/IL border at the beginning of the period. The resulting convectively induced vorticity maximum and attendant isolated showers and thunderstorms are expected to gradually move eastward this morning. A very moist and diurnally destabilized air mass is expected downstream across Lower MI and the OH Valley. As a result, thunderstorms associated with this vorticity maximum are expected to reintensify as they move into Lower MI and the middle OH Valley this afternoon. The anticipated trajectory of vorticity maximum currently takes it over Lower MI during the afternoon. Enhanced mid-level flow will accompany this vorticity maximum, resulting in strong enough vertical shear to support more organized storm structures capable of damaging wind gusts and isolated hail. Highest concentration of severe storms is currently expected to be across southern portions of Lower MI and adjacent northeast IN and northwest OH. Another round of thunderstorms is possible over the region as the cold front moves through this evening, but development of these storms is largely dependent on the strength of the antecedent storms and air mass recovery in their wake. ...Lower Great Lakes into the Northeast... Low-amplitude shortwave trough currently moving through the middle OH Valley will continue eastward/northeastward, reaching the Lower Great Lakes/Northeast region by the early afternoon. Despite relatively modest lapse rates, surface dewpoints in the upper 60s (isolated low 70s possible) and surface temperatures in the mid 80s will still support moderate buoyancy capable of occasionally strong updrafts. Vertical shear will be modest and a predominantly linear multicell mode is anticipated. Water-loaded downbursts are possible with strongest storms. ...Ozark Plateau into OK... A very warm and moist low-level air mass will remain in place across the region with afternoon dewpoints in the 70s and temperatures in the upper 90s/low 100s. Steep mid-level lapse rates atop this warm and moist air mass will result in very strong buoyancy (i.e. MLCAPE greater than 3000 J/kg) but also modest convective inhibition. Impetus for overcoming this convective inhibition and initiating deep updrafts is expected to be the cold front moving south through the region. However, location of the cold front this afternoon is uncertain, primarily because of potential modification of its position as a result of outflow from the ongoing MCS across KS. There is also some chance for the MCS to remain over northeast OK and the Ozark Plateau long enough to prevent air mass recovery. These uncertainties merit keeping Marginal severe probabilities for this forecast, but an upgrade may be needed in a subsequent outlook as these mesoscale details become more certain. ..Mosier/Nauslar.. 08/18/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Aug 18 2019 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER LOWER MI...NORTHEAST IN...AND FAR NORTHWEST OH... ...SUMMARY... Scattered thunderstorms capable of severe gusts and large hail are possible over Lower Michigan, northeast Indiana, and far northwest Ohio this afternoon into the early evening. ...Middle MS Valley through OH Valley and Upper Great Lakes... Well-organized MCS currently moving through southern MN and northern IA will likely be in the vicinity of the IA/IL border at the beginning of the period. The resulting convectively induced vorticity maximum and attendant isolated showers and thunderstorms are expected to gradually move eastward this morning. A very moist and diurnally destabilized air mass is expected downstream across Lower MI and the OH Valley. As a result, thunderstorms associated with this vorticity maximum are expected to reintensify as they move into Lower MI and the middle OH Valley this afternoon. The anticipated trajectory of vorticity maximum currently takes it over Lower MI during the afternoon. Enhanced mid-level flow will accompany this vorticity maximum, resulting in strong enough vertical shear to support more organized storm structures capable of damaging wind gusts and isolated hail. Highest concentration of severe storms is currently expected to be across southern portions of Lower MI and adjacent northeast IN and northwest OH. Another round of thunderstorms is possible over the region as the cold front moves through this evening, but development of these storms is largely dependent on the strength of the antecedent storms and air mass recovery in their wake. ...Lower Great Lakes into the Northeast... Low-amplitude shortwave trough currently moving through the middle OH Valley will continue eastward/northeastward, reaching the Lower Great Lakes/Northeast region by the early afternoon. Despite relatively modest lapse rates, surface dewpoints in the upper 60s (isolated low 70s possible) and surface temperatures in the mid 80s will still support moderate buoyancy capable of occasionally strong updrafts. Vertical shear will be modest and a predominantly linear multicell mode is anticipated. Water-loaded downbursts are possible with strongest storms. ...Ozark Plateau into OK... A very warm and moist low-level air mass will remain in place across the region with afternoon dewpoints in the 70s and temperatures in the upper 90s/low 100s. Steep mid-level lapse rates atop this warm and moist air mass will result in very strong buoyancy (i.e. MLCAPE greater than 3000 J/kg) but also modest convective inhibition. Impetus for overcoming this convective inhibition and initiating deep updrafts is expected to be the cold front moving south through the region. However, location of the cold front this afternoon is uncertain, primarily because of potential modification of its position as a result of outflow from the ongoing MCS across KS. There is also some chance for the MCS to remain over northeast OK and the Ozark Plateau long enough to prevent air mass recovery. These uncertainties merit keeping Marginal severe probabilities for this forecast, but an upgrade may be needed in a subsequent outlook as these mesoscale details become more certain. ..Mosier/Nauslar.. 08/18/2019 Read more

000
ABPZ20 KNHC 180530
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sat Aug 17 2019

For the eastern North Pacific...east of 140 degrees west longitude:

An area of low pressure located a couple of hundred miles south of
the coast of Guatemala is producing a limited area of disorganized
showers and thunderstorms tonight. Environmental conditions are
expected to become more conducive for development by early next
week, and a tropical depression is expected to form by Tuesday while
the low moves west-northwestward at about 10 mph parallel to the
coast of Mexico. Moisture associated with the low is forecast to
produce heavy rainfall and possible flash flooding across portions
of El Salvador, Guatemala, and southeastern Mexico during the next
few days.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...90 percent.

Shower and thunderstorm activity associated with a tropical wave
located about 900 miles south-southwest of the southern tip of the
Baja California has increased since yesterday. Environmental
conditions continue to support slow development, and this system
has the potential to become a tropical cyclone by the middle of next
week while it moves westward to west-northwestward at 5 to 10 mph.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...40 percent.

Another tropical wave, located about 1300 miles west-southwest of
the southern tip of the Baja California peninsula, is producing
cloudiness and showers. Some development of this system is
possible during the next couple of days while it moves slowly
westward across the southwestern portion of the eastern Pacific.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Blake

MD 1782 CONCERNING SEVERE THUNDERSTORM WATCH 593...595... FOR PORTIONS OF SOUTHERN MN...NORTHERN/CENTRAL IA...FAR SOUTHWESTERN WI...AND NORTHEASTERN NE
Mesoscale Discussion 1782 NWS Storm Prediction Center Norman OK 1200 AM CDT Sun Aug 18 2019 Areas affected...Portions of southern MN...northern/central IA...far southwestern WI...and northeastern NE Concerning...Severe Thunderstorm Watch 593...595... Valid 180500Z - 180630Z The severe weather threat for Severe Thunderstorm Watch 593, 595 continues. SUMMARY...A strong to damaging wind threat continues across Severe Thunderstorm Watch 593 and 595. Downstream watch issuance is possible in the next 1-2 hours depending on observational trends. DISCUSSION...A small bow echo is occurring across southwestern MN into northwestern IA per recent radar imagery. Measured severe wind gusts with this bow have generally remained sub-severe (50-56 mph) over the past couple of hours. Still, isolated strong to damaging wind gusts will remain possible with these storms as they continue eastward across northern IA and south-central MN over the next couple of hours. Instability decreases with eastward extent into northeastern IA and far southwestern WI per 04Z mesoanalysis. This lends some uncertainty to the intensity of this convection through the overnight hours. But, a 35-45 kt southwesterly low-level jet and similar values of effective bulk shear may support continued storm maintenance/intensity. Depending on observational trends, a downstream watch may be needed within the next 1-2 hours. In addition, some backbuilding of convection along a surface cold front may occur from northeastern NE into central IA. This activity would also pose an isolated wind/hail threat. Severe Thunderstorm Watch 593/595 may need to be extended in area and/or time to account for this potential. ..Gleason.. 08/18/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX... LAT...LON 42559823 43089701 43189580 43369523 43859498 44329532 44619497 44039186 43679081 42529081 41849228 41679520 41709749 42559823 Read more

WW 0594 Status Updates
STATUS REPORT ON WW 594 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SSW HLC TO 30 WNW RSL TO 25 ESE MHK. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1781 ..GLEASON..08/18/19 ATTN...WFO...ICT...TOP...DDC...GID... STATUS REPORT FOR WS 594 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC003-009-015-017-019-031-035-041-049-051-053-061-073-079-095- 105-111-113-115-127-135-143-145-155-159-165-167-169-173-185-191- 195-180540- KS . KANSAS COUNTIES INCLUDED ARE ANDERSON BARTON BUTLER CHASE CHAUTAUQUA COFFEY COWLEY DICKINSON ELK ELLIS ELLSWORTH GEARY GREENWOOD HARVEY KINGMAN LINCOLN LYON MCPHERSON MARION MORRIS NESS OTTAWA PAWNEE RENO RICE RUSH RUSSELL SALINE SEDGWICK STAFFORD SUMNER TREGO THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES Read more