Aggregator

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/NORTHERN ROCKIES AND PLAINS INTO MUCH OF MINNESOTA... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A shortwave trough initially over the Great Basin/Intermountain West is forecast to move east-southeastward and gradually deamplify on Wednesday, as it begins to merge with a more prominent upper-level trough that will cover parts of the Canadian Prairies into the northern/central Plains. Multiple embedded shortwaves within the larger trough will likely move across parts of the Dakotas and Minnesota. A weak surface wave may develop during the afternoon along a cold front that will extend from parts of MN and the Dakotas into the central Plains. ...Parts of the northern/central Rockies/Plains into Minnesota... A large area of at least low-end severe potential may evolve from parts of the central/northern Rockies/Plains into Minnesota. The Marginal Risk has been maintained with some minor adjustments; further refinement to the risk area is likely if areas of relatively lower or higher threat become evident with time. Scattered thunderstorms may develop relatively early in the day across the higher terrain of CO/WY/MT, in association with the shortwave trough emerging from the Intermountain West. While low-level moisture will likely remain rather limited, steep midlevel lapse rates and modestly favorable deep-layer shear could support a few organized multicells and perhaps a marginal supercell or two, as convection spreads towards the central/northern High Plains. Isolated strong to severe gusts and hail will be possible. Some outflow consolidation could support one or more loosely organized clusters evolving with time, with a threat of strong to locally severe gusts as storms move eastward into the evening. Farther northeast, details regarding destabilization and storm development/evolution from the eastern Dakotas into MN remain uncertain. Some guidance suggests potential for an embedded shortwave or MCV to move across the region during the afternoon/evening, which could aid in isolated storm development near the front, if sufficient moistening and destabilization can occur. There will also be some potential for storms to develop and/or spread into the region from the west during the evening, as the larger-scale upper trough begins to amplify. Relatively steep midlevel lapse rates and adequate deep-layer shear could support isolated hail and damaging gusts with the strongest storms. ..Dean.. 09/03/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/NORTHERN ROCKIES AND PLAINS INTO MUCH OF MINNESOTA... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A shortwave trough initially over the Great Basin/Intermountain West is forecast to move east-southeastward and gradually deamplify on Wednesday, as it begins to merge with a more prominent upper-level trough that will cover parts of the Canadian Prairies into the northern/central Plains. Multiple embedded shortwaves within the larger trough will likely move across parts of the Dakotas and Minnesota. A weak surface wave may develop during the afternoon along a cold front that will extend from parts of MN and the Dakotas into the central Plains. ...Parts of the northern/central Rockies/Plains into Minnesota... A large area of at least low-end severe potential may evolve from parts of the central/northern Rockies/Plains into Minnesota. The Marginal Risk has been maintained with some minor adjustments; further refinement to the risk area is likely if areas of relatively lower or higher threat become evident with time. Scattered thunderstorms may develop relatively early in the day across the higher terrain of CO/WY/MT, in association with the shortwave trough emerging from the Intermountain West. While low-level moisture will likely remain rather limited, steep midlevel lapse rates and modestly favorable deep-layer shear could support a few organized multicells and perhaps a marginal supercell or two, as convection spreads towards the central/northern High Plains. Isolated strong to severe gusts and hail will be possible. Some outflow consolidation could support one or more loosely organized clusters evolving with time, with a threat of strong to locally severe gusts as storms move eastward into the evening. Farther northeast, details regarding destabilization and storm development/evolution from the eastern Dakotas into MN remain uncertain. Some guidance suggests potential for an embedded shortwave or MCV to move across the region during the afternoon/evening, which could aid in isolated storm development near the front, if sufficient moistening and destabilization can occur. There will also be some potential for storms to develop and/or spread into the region from the west during the evening, as the larger-scale upper trough begins to amplify. Relatively steep midlevel lapse rates and adequate deep-layer shear could support isolated hail and damaging gusts with the strongest storms. ..Dean.. 09/03/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL/NORTHERN ROCKIES AND PLAINS INTO MUCH OF MINNESOTA... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A shortwave trough initially over the Great Basin/Intermountain West is forecast to move east-southeastward and gradually deamplify on Wednesday, as it begins to merge with a more prominent upper-level trough that will cover parts of the Canadian Prairies into the northern/central Plains. Multiple embedded shortwaves within the larger trough will likely move across parts of the Dakotas and Minnesota. A weak surface wave may develop during the afternoon along a cold front that will extend from parts of MN and the Dakotas into the central Plains. ...Parts of the northern/central Rockies/Plains into Minnesota... A large area of at least low-end severe potential may evolve from parts of the central/northern Rockies/Plains into Minnesota. The Marginal Risk has been maintained with some minor adjustments; further refinement to the risk area is likely if areas of relatively lower or higher threat become evident with time. Scattered thunderstorms may develop relatively early in the day across the higher terrain of CO/WY/MT, in association with the shortwave trough emerging from the Intermountain West. While low-level moisture will likely remain rather limited, steep midlevel lapse rates and modestly favorable deep-layer shear could support a few organized multicells and perhaps a marginal supercell or two, as convection spreads towards the central/northern High Plains. Isolated strong to severe gusts and hail will be possible. Some outflow consolidation could support one or more loosely organized clusters evolving with time, with a threat of strong to locally severe gusts as storms move eastward into the evening. Farther northeast, details regarding destabilization and storm development/evolution from the eastern Dakotas into MN remain uncertain. Some guidance suggests potential for an embedded shortwave or MCV to move across the region during the afternoon/evening, which could aid in isolated storm development near the front, if sufficient moistening and destabilization can occur. There will also be some potential for storms to develop and/or spread into the region from the west during the evening, as the larger-scale upper trough begins to amplify. Relatively steep midlevel lapse rates and adequate deep-layer shear could support isolated hail and damaging gusts with the strongest storms. ..Dean.. 09/03/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 03 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING ACROSS PARTS OF CENTRAL IDAHO...MUCH OF SOUTHERN MONTANA...WYOMING...MUCH OF NORTHERN UTAH AND ADJACENT NORTHWESTERN COLORADO...INTO PARTS OF THE WESTERN DAKOTAS... ...SUMMARY... Thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin by this afternoon may produce scattered strong to locally severe wind gusts, before spreading eastward toward the northern Great Plains into this evening. ...Synopsis... Downstream of split mid/upper flow across the eastern Pacific, Alaska and Canadian Yukon vicinity, the stronger westerlies remain confined to the higher latitudes, with weaker zonal flow prevailing across the northern tier of the U.S., on the northern periphery of weak/suppressed subtropical ridging. Seasonably moist boundary-layer air has generally become confined to the southern tier of the U.S., to the south of notable surface ridging. Little change appears likely through this period, though the center of the ridge may shift from the lower Great Lakes/upper Ohio Valley into the northern Mid Atlantic. It does appear that the westerlies may undergo some amplification across the northeastern Pacific into Canada later today through tonight, including building mid-level ridging offshore of the Pacific Northwest and British Columbia coast and digging mid-level troughing to the lee of the Canadian Rockies. As this occurs, a remnant mid-level trough over the interior northwestern U.S. is forecast to slowly shift into and across the northern Rockies. ...Northern Intermountain Region and Rockies... Models indicate that the mid-level trough will weaken while shifting eastward today, but it still appears that mid-level forcing for ascent and cooling will remain sufficient to support continuing convective development, including considerable thunderstorm activity this afternoon and evening across the higher terrain. Near the mid-level cold core, destabilization, including mixed-layer CAPE on the order of 500-1000 J/kg, might support a few thunderstorms capable of producing marginally severe hail across the mountains of southwestern Montana. Otherwise, more modest CAPE, based above a warm and deeply mixed boundary layer, may still become supportive of locally strong to severe downburst winds across the higher terrain of western Wyoming and northern Utah, into the Great Salt Lake Desert. Eastward into the northern high plains, severe weather potential, and the extent to which destabilization is able to maintain thunderstorm development, remains more uncertain. However, some model output, perhaps most notably the past few runs of the NAM, has been suggestive that convective development near/north of the Absaroka Range and Big Horn Basin vicinity may generate sufficient consolidating outflow to support a substantive east-southeastward propagating surface cold pool to the lee of the higher terrain. Although 03/00Z NAM forecast soundings, for example, are not particularly indicative that vigorous thunderstorm development will be maintained, they suggest that 35-50 kt winds may accompany a surging gust front, in this run across southeastern Montana and adjacent northeastern Wyoming by late evening and into western South Dakota overnight. ..Kerr/Moore.. 09/03/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 03 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING ACROSS PARTS OF CENTRAL IDAHO...MUCH OF SOUTHERN MONTANA...WYOMING...MUCH OF NORTHERN UTAH AND ADJACENT NORTHWESTERN COLORADO...INTO PARTS OF THE WESTERN DAKOTAS... ...SUMMARY... Thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin by this afternoon may produce scattered strong to locally severe wind gusts, before spreading eastward toward the northern Great Plains into this evening. ...Synopsis... Downstream of split mid/upper flow across the eastern Pacific, Alaska and Canadian Yukon vicinity, the stronger westerlies remain confined to the higher latitudes, with weaker zonal flow prevailing across the northern tier of the U.S., on the northern periphery of weak/suppressed subtropical ridging. Seasonably moist boundary-layer air has generally become confined to the southern tier of the U.S., to the south of notable surface ridging. Little change appears likely through this period, though the center of the ridge may shift from the lower Great Lakes/upper Ohio Valley into the northern Mid Atlantic. It does appear that the westerlies may undergo some amplification across the northeastern Pacific into Canada later today through tonight, including building mid-level ridging offshore of the Pacific Northwest and British Columbia coast and digging mid-level troughing to the lee of the Canadian Rockies. As this occurs, a remnant mid-level trough over the interior northwestern U.S. is forecast to slowly shift into and across the northern Rockies. ...Northern Intermountain Region and Rockies... Models indicate that the mid-level trough will weaken while shifting eastward today, but it still appears that mid-level forcing for ascent and cooling will remain sufficient to support continuing convective development, including considerable thunderstorm activity this afternoon and evening across the higher terrain. Near the mid-level cold core, destabilization, including mixed-layer CAPE on the order of 500-1000 J/kg, might support a few thunderstorms capable of producing marginally severe hail across the mountains of southwestern Montana. Otherwise, more modest CAPE, based above a warm and deeply mixed boundary layer, may still become supportive of locally strong to severe downburst winds across the higher terrain of western Wyoming and northern Utah, into the Great Salt Lake Desert. Eastward into the northern high plains, severe weather potential, and the extent to which destabilization is able to maintain thunderstorm development, remains more uncertain. However, some model output, perhaps most notably the past few runs of the NAM, has been suggestive that convective development near/north of the Absaroka Range and Big Horn Basin vicinity may generate sufficient consolidating outflow to support a substantive east-southeastward propagating surface cold pool to the lee of the higher terrain. Although 03/00Z NAM forecast soundings, for example, are not particularly indicative that vigorous thunderstorm development will be maintained, they suggest that 35-50 kt winds may accompany a surging gust front, in this run across southeastern Montana and adjacent northeastern Wyoming by late evening and into western South Dakota overnight. ..Kerr/Moore.. 09/03/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 03 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING ACROSS PARTS OF CENTRAL IDAHO...MUCH OF SOUTHERN MONTANA...WYOMING...MUCH OF NORTHERN UTAH AND ADJACENT NORTHWESTERN COLORADO...INTO PARTS OF THE WESTERN DAKOTAS... ...SUMMARY... Thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin by this afternoon may produce scattered strong to locally severe wind gusts, before spreading eastward toward the northern Great Plains into this evening. ...Synopsis... Downstream of split mid/upper flow across the eastern Pacific, Alaska and Canadian Yukon vicinity, the stronger westerlies remain confined to the higher latitudes, with weaker zonal flow prevailing across the northern tier of the U.S., on the northern periphery of weak/suppressed subtropical ridging. Seasonably moist boundary-layer air has generally become confined to the southern tier of the U.S., to the south of notable surface ridging. Little change appears likely through this period, though the center of the ridge may shift from the lower Great Lakes/upper Ohio Valley into the northern Mid Atlantic. It does appear that the westerlies may undergo some amplification across the northeastern Pacific into Canada later today through tonight, including building mid-level ridging offshore of the Pacific Northwest and British Columbia coast and digging mid-level troughing to the lee of the Canadian Rockies. As this occurs, a remnant mid-level trough over the interior northwestern U.S. is forecast to slowly shift into and across the northern Rockies. ...Northern Intermountain Region and Rockies... Models indicate that the mid-level trough will weaken while shifting eastward today, but it still appears that mid-level forcing for ascent and cooling will remain sufficient to support continuing convective development, including considerable thunderstorm activity this afternoon and evening across the higher terrain. Near the mid-level cold core, destabilization, including mixed-layer CAPE on the order of 500-1000 J/kg, might support a few thunderstorms capable of producing marginally severe hail across the mountains of southwestern Montana. Otherwise, more modest CAPE, based above a warm and deeply mixed boundary layer, may still become supportive of locally strong to severe downburst winds across the higher terrain of western Wyoming and northern Utah, into the Great Salt Lake Desert. Eastward into the northern high plains, severe weather potential, and the extent to which destabilization is able to maintain thunderstorm development, remains more uncertain. However, some model output, perhaps most notably the past few runs of the NAM, has been suggestive that convective development near/north of the Absaroka Range and Big Horn Basin vicinity may generate sufficient consolidating outflow to support a substantive east-southeastward propagating surface cold pool to the lee of the higher terrain. Although 03/00Z NAM forecast soundings, for example, are not particularly indicative that vigorous thunderstorm development will be maintained, they suggest that 35-50 kt winds may accompany a surging gust front, in this run across southeastern Montana and adjacent northeastern Wyoming by late evening and into western South Dakota overnight. ..Kerr/Moore.. 09/03/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 03 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING ACROSS PARTS OF CENTRAL IDAHO...MUCH OF SOUTHERN MONTANA...WYOMING...MUCH OF NORTHERN UTAH AND ADJACENT NORTHWESTERN COLORADO...INTO PARTS OF THE WESTERN DAKOTAS... ...SUMMARY... Thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin by this afternoon may produce scattered strong to locally severe wind gusts, before spreading eastward toward the northern Great Plains into this evening. ...Synopsis... Downstream of split mid/upper flow across the eastern Pacific, Alaska and Canadian Yukon vicinity, the stronger westerlies remain confined to the higher latitudes, with weaker zonal flow prevailing across the northern tier of the U.S., on the northern periphery of weak/suppressed subtropical ridging. Seasonably moist boundary-layer air has generally become confined to the southern tier of the U.S., to the south of notable surface ridging. Little change appears likely through this period, though the center of the ridge may shift from the lower Great Lakes/upper Ohio Valley into the northern Mid Atlantic. It does appear that the westerlies may undergo some amplification across the northeastern Pacific into Canada later today through tonight, including building mid-level ridging offshore of the Pacific Northwest and British Columbia coast and digging mid-level troughing to the lee of the Canadian Rockies. As this occurs, a remnant mid-level trough over the interior northwestern U.S. is forecast to slowly shift into and across the northern Rockies. ...Northern Intermountain Region and Rockies... Models indicate that the mid-level trough will weaken while shifting eastward today, but it still appears that mid-level forcing for ascent and cooling will remain sufficient to support continuing convective development, including considerable thunderstorm activity this afternoon and evening across the higher terrain. Near the mid-level cold core, destabilization, including mixed-layer CAPE on the order of 500-1000 J/kg, might support a few thunderstorms capable of producing marginally severe hail across the mountains of southwestern Montana. Otherwise, more modest CAPE, based above a warm and deeply mixed boundary layer, may still become supportive of locally strong to severe downburst winds across the higher terrain of western Wyoming and northern Utah, into the Great Salt Lake Desert. Eastward into the northern high plains, severe weather potential, and the extent to which destabilization is able to maintain thunderstorm development, remains more uncertain. However, some model output, perhaps most notably the past few runs of the NAM, has been suggestive that convective development near/north of the Absaroka Range and Big Horn Basin vicinity may generate sufficient consolidating outflow to support a substantive east-southeastward propagating surface cold pool to the lee of the higher terrain. Although 03/00Z NAM forecast soundings, for example, are not particularly indicative that vigorous thunderstorm development will be maintained, they suggest that 35-50 kt winds may accompany a surging gust front, in this run across southeastern Montana and adjacent northeastern Wyoming by late evening and into western South Dakota overnight. ..Kerr/Moore.. 09/03/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 03 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING ACROSS PARTS OF CENTRAL IDAHO...MUCH OF SOUTHERN MONTANA...WYOMING...MUCH OF NORTHERN UTAH AND ADJACENT NORTHWESTERN COLORADO...INTO PARTS OF THE WESTERN DAKOTAS... ...SUMMARY... Thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin by this afternoon may produce scattered strong to locally severe wind gusts, before spreading eastward toward the northern Great Plains into this evening. ...Synopsis... Downstream of split mid/upper flow across the eastern Pacific, Alaska and Canadian Yukon vicinity, the stronger westerlies remain confined to the higher latitudes, with weaker zonal flow prevailing across the northern tier of the U.S., on the northern periphery of weak/suppressed subtropical ridging. Seasonably moist boundary-layer air has generally become confined to the southern tier of the U.S., to the south of notable surface ridging. Little change appears likely through this period, though the center of the ridge may shift from the lower Great Lakes/upper Ohio Valley into the northern Mid Atlantic. It does appear that the westerlies may undergo some amplification across the northeastern Pacific into Canada later today through tonight, including building mid-level ridging offshore of the Pacific Northwest and British Columbia coast and digging mid-level troughing to the lee of the Canadian Rockies. As this occurs, a remnant mid-level trough over the interior northwestern U.S. is forecast to slowly shift into and across the northern Rockies. ...Northern Intermountain Region and Rockies... Models indicate that the mid-level trough will weaken while shifting eastward today, but it still appears that mid-level forcing for ascent and cooling will remain sufficient to support continuing convective development, including considerable thunderstorm activity this afternoon and evening across the higher terrain. Near the mid-level cold core, destabilization, including mixed-layer CAPE on the order of 500-1000 J/kg, might support a few thunderstorms capable of producing marginally severe hail across the mountains of southwestern Montana. Otherwise, more modest CAPE, based above a warm and deeply mixed boundary layer, may still become supportive of locally strong to severe downburst winds across the higher terrain of western Wyoming and northern Utah, into the Great Salt Lake Desert. Eastward into the northern high plains, severe weather potential, and the extent to which destabilization is able to maintain thunderstorm development, remains more uncertain. However, some model output, perhaps most notably the past few runs of the NAM, has been suggestive that convective development near/north of the Absaroka Range and Big Horn Basin vicinity may generate sufficient consolidating outflow to support a substantive east-southeastward propagating surface cold pool to the lee of the higher terrain. Although 03/00Z NAM forecast soundings, for example, are not particularly indicative that vigorous thunderstorm development will be maintained, they suggest that 35-50 kt winds may accompany a surging gust front, in this run across southeastern Montana and adjacent northeastern Wyoming by late evening and into western South Dakota overnight. ..Kerr/Moore.. 09/03/2024 Read more

000
ABPZ20 KNHC 030523
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Mon Sep 2 2024

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

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Roberts

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 PM CDT Mon Sep 02 2024 Valid 030100Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING ACROSS PARTS OF NORTHEASTERN OREGON...SOUTHEASTERN WASHINGTON...CENTRAL IDAHO AND ADJACENT SOUTHWESTERN MONTANA... ...SUMMARY... Widely scattered strong to severe wind gusts remain possible near lingering thunderstorm activity across parts of the northern Intermountain Region through this evening. ...01Z Update... Lower/mid-tropospheric subsidence and drying are probably tending to suppress ongoing scattered thunderstorm development across the Great Basin into adjacent northern Intermountain Region. However, widely scattered stronger thunderstorm development remains possible into this evening, within favorable large-scale forcing for ascent in the exit region of a vigorous upper jet streak (including 70+ kt around 300 mb) nosing north-northeastward through eastern Oregon, and in the downstream lower/mid-level warm advection regime overspreading central Idaho. Even within this regime, higher precipitable water on the order of .7-.8 inches appears to be supporting only weak CAPE (e.g. little more than 100 J/kg of mixed-layer CAPE in the 03/00Z sounding from Boise, ID), and this is limiting the strength of the updrafts and associated precipitation, which in turn is limiting the strength of downdraft potential despite being rooted above a warm and deeply mixed boundary layer. The potential for stronger gusts, aided by downward mixing of higher momentum from aloft, seems likely to remain generally focused across the higher elevations of north central and northeastern Oregon into the mountains of central Idaho, before convection weakens later this evening. ..Kerr.. 09/03/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 PM CDT Mon Sep 02 2024 Valid 030100Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING ACROSS PARTS OF NORTHEASTERN OREGON...SOUTHEASTERN WASHINGTON...CENTRAL IDAHO AND ADJACENT SOUTHWESTERN MONTANA... ...SUMMARY... Widely scattered strong to severe wind gusts remain possible near lingering thunderstorm activity across parts of the northern Intermountain Region through this evening. ...01Z Update... Lower/mid-tropospheric subsidence and drying are probably tending to suppress ongoing scattered thunderstorm development across the Great Basin into adjacent northern Intermountain Region. However, widely scattered stronger thunderstorm development remains possible into this evening, within favorable large-scale forcing for ascent in the exit region of a vigorous upper jet streak (including 70+ kt around 300 mb) nosing north-northeastward through eastern Oregon, and in the downstream lower/mid-level warm advection regime overspreading central Idaho. Even within this regime, higher precipitable water on the order of .7-.8 inches appears to be supporting only weak CAPE (e.g. little more than 100 J/kg of mixed-layer CAPE in the 03/00Z sounding from Boise, ID), and this is limiting the strength of the updrafts and associated precipitation, which in turn is limiting the strength of downdraft potential despite being rooted above a warm and deeply mixed boundary layer. The potential for stronger gusts, aided by downward mixing of higher momentum from aloft, seems likely to remain generally focused across the higher elevations of north central and northeastern Oregon into the mountains of central Idaho, before convection weakens later this evening. ..Kerr.. 09/03/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 PM CDT Mon Sep 02 2024 Valid 030100Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING ACROSS PARTS OF NORTHEASTERN OREGON...SOUTHEASTERN WASHINGTON...CENTRAL IDAHO AND ADJACENT SOUTHWESTERN MONTANA... ...SUMMARY... Widely scattered strong to severe wind gusts remain possible near lingering thunderstorm activity across parts of the northern Intermountain Region through this evening. ...01Z Update... Lower/mid-tropospheric subsidence and drying are probably tending to suppress ongoing scattered thunderstorm development across the Great Basin into adjacent northern Intermountain Region. However, widely scattered stronger thunderstorm development remains possible into this evening, within favorable large-scale forcing for ascent in the exit region of a vigorous upper jet streak (including 70+ kt around 300 mb) nosing north-northeastward through eastern Oregon, and in the downstream lower/mid-level warm advection regime overspreading central Idaho. Even within this regime, higher precipitable water on the order of .7-.8 inches appears to be supporting only weak CAPE (e.g. little more than 100 J/kg of mixed-layer CAPE in the 03/00Z sounding from Boise, ID), and this is limiting the strength of the updrafts and associated precipitation, which in turn is limiting the strength of downdraft potential despite being rooted above a warm and deeply mixed boundary layer. The potential for stronger gusts, aided by downward mixing of higher momentum from aloft, seems likely to remain generally focused across the higher elevations of north central and northeastern Oregon into the mountains of central Idaho, before convection weakens later this evening. ..Kerr.. 09/03/2024 Read more

882
ABPZ20 KNHC 022343
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Mon Sep 2 2024

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

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Pasch

No watches are valid as of Mon Sep 2 22:32:01 UTC 2024.

No Mesoscale Discussions are in effect as of Mon Sep 2 22:32:01 UTC 2024.

MD 2043 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EASTERN OREGON INTO NORTHEAST NEVADA AND WESTERN INTO CENTRAL IDAHO
Mesoscale Discussion 2043 NWS Storm Prediction Center Norman OK 0356 PM CDT Mon Sep 02 2024 Areas affected...portions of eastern Oregon into northeast Nevada and western into central Idaho Concerning...Severe potential...Watch unlikely Valid 022056Z - 022230Z Probability of Watch Issuance...5 percent SUMMARY...A couple of strong to severe gusts may accompany the deeper storm cores that manage to develop. Any severe threat that materializes should be sparse, and a WW issuance is not expected. DISCUSSION...A pronounced 500 mb vort max is currently traversing the CA/OR border, aiding in the ascent of marginally buoyant boundary-layer based parcels. MRMS mosaic radar imagery shows convective initiation underway from the lee of the Cascades toward eastern ID. These storms are developing atop a very dry boundary layer (evident via 50-60 F surface temperature/dewpoint spreads), with RAP forecast soundings showing inverted-v soundings extending up to 500 mb. As such, these storms will be high-based in nature. Strong mid-level flow is overspreading portions of the Interior West ahead of the approaching trough, contributing to 30+ kts of effective bulk shear. As such, a few storms may become marginally organized, capable producing strong to potentially severe gusts. However, severe potential is highly dependent on how vertically deep storm cores can become. The severe gust threat is expected to be sparse, and a WW issuance is not anticipated. ..Squitieri/Smith.. 09/02/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TFX...SLC...PIH...MSO...BOI...LKN...OTX...PDT... MFR... LAT...LON 44142133 44812118 45552062 46051987 46361816 45771419 44861296 43951263 41821330 40791411 40221486 40001533 40001577 40221636 40551693 41031717 41781741 42351781 42831848 43191920 43472024 43572053 44142133 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0454 PM CDT Mon Sep 02 2024 Valid 041200Z - 101200Z Fire concerns will remain low in the extended. High pressure will build in across the western US D3/Wednesday through D6/Saturday, with a warming and drying trend. As this occurs, monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest through D5/Friday. Winds will remain mostly light where fuels are dry, keeping fire weather concerns low. Moisture will slowly begin to return northward by D7/Sun-D8/Mon. Across the High Plains, southerly flow will slowly bring moisture northward, with several disturbances will bringing occasional chances for rain and thunderstorm activity. This should bring some relief to very dry conditions and help improve status of fuels. Occasional post-frontal northwesterly breezes will be possible, but relative humidity looks to remain above critical thresholds. ..Thornton.. 09/02/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0454 PM CDT Mon Sep 02 2024 Valid 041200Z - 101200Z Fire concerns will remain low in the extended. High pressure will build in across the western US D3/Wednesday through D6/Saturday, with a warming and drying trend. As this occurs, monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest through D5/Friday. Winds will remain mostly light where fuels are dry, keeping fire weather concerns low. Moisture will slowly begin to return northward by D7/Sun-D8/Mon. Across the High Plains, southerly flow will slowly bring moisture northward, with several disturbances will bringing occasional chances for rain and thunderstorm activity. This should bring some relief to very dry conditions and help improve status of fuels. Occasional post-frontal northwesterly breezes will be possible, but relative humidity looks to remain above critical thresholds. ..Thornton.. 09/02/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0454 PM CDT Mon Sep 02 2024 Valid 041200Z - 101200Z Fire concerns will remain low in the extended. High pressure will build in across the western US D3/Wednesday through D6/Saturday, with a warming and drying trend. As this occurs, monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest through D5/Friday. Winds will remain mostly light where fuels are dry, keeping fire weather concerns low. Moisture will slowly begin to return northward by D7/Sun-D8/Mon. Across the High Plains, southerly flow will slowly bring moisture northward, with several disturbances will bringing occasional chances for rain and thunderstorm activity. This should bring some relief to very dry conditions and help improve status of fuels. Occasional post-frontal northwesterly breezes will be possible, but relative humidity looks to remain above critical thresholds. ..Thornton.. 09/02/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0454 PM CDT Mon Sep 02 2024 Valid 041200Z - 101200Z Fire concerns will remain low in the extended. High pressure will build in across the western US D3/Wednesday through D6/Saturday, with a warming and drying trend. As this occurs, monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest through D5/Friday. Winds will remain mostly light where fuels are dry, keeping fire weather concerns low. Moisture will slowly begin to return northward by D7/Sun-D8/Mon. Across the High Plains, southerly flow will slowly bring moisture northward, with several disturbances will bringing occasional chances for rain and thunderstorm activity. This should bring some relief to very dry conditions and help improve status of fuels. Occasional post-frontal northwesterly breezes will be possible, but relative humidity looks to remain above critical thresholds. ..Thornton.. 09/02/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more