Storm Prediction Center

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0348 PM CST Wed Dec 17 2025 Valid 191200Z - 251200Z Fire weather concerns are expected to persist through the remainder of the work week and into the weekend across the southern Plains and central/southern High Plains. A largely zonal upper-level flow regime is expected to persist through early next week before broad scale ridging becomes established over the south-central CONUS. This synoptic regime will favor lee troughing followed by frontal passages across the Plains with rain/snow chances for most regions, except for the Southwest/southern Plains where dry conditions will persist for the next several days. Long-range ensembles do show the potential for widespread precipitation late in the forecast period (D6/Mon to D8/Wed) for parts of the Southwest, but steady fuel drying is anticipated for the southern Plains/High Plains through next week. ...D3/Friday - High Plains/southern Plains... Dry conditions will prevail across the southern Plains early D3/Friday in the wake of Thursday's frontal passage. A surface high shifting eastward into the lower MS Valley will promote southwesterly winds across much of TX, OK, and KS. Coincidentally, an upper-disturbance moving across the northern Rockies will promote lee troughing along the High Plains, which will induce another downslope flow regime along the central Rockies and augment the pressure gradient over the Plains. 15-25 mph winds are anticipated within the dry return flow regime with RH reductions into the 15-25% range probable from the Permian Basin into western OK. In the lee of the Rockies, confidence in RH reductions is limited, but a strong wind signal coupled with drying fine fuels should promote at least a wind-driven fire weather concern. ...D4/Saturday - southern High Plains... A cold front associated with a northern Plains/Great Lakes surface low will gradually push into the southern Plains through the day Saturday. While confidence in how far south this front will progress by peak heating remains uncertain, the general consensus among guidance is that 15-20 mph westerly pre-frontal winds will support adequate downslope warming/drying for areas of elevated to critical fire weather conditions. ..Moore.. 12/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CST Wed Dec 17 2025 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential will be limited on Thursday, but isolated strong wind gusts are possible across portions of the Lower Ohio and Tennessee Valleys. ...Synopsis... A strong upper trough will move across Midwest on Thursday with low pressure moving across the Great Lakes. A cold front will extend south from this low with wind shift moving across the OH and TN Valleys during the day and into the evening. Minimal destabilization is forecast ahead of the front as clouds and early day precipitation hamper heating. Mostly elevated instability is forecast, though shear profiles will be strong. Despite a marginal/cool boundary layer across the warm sector, deeper ascent along the cold front could support shallow moist convection capable of augmenting gusts with the frontal passage. Elsewhere, moisture and instability will increase overnight well off the NC Coast, but supercells developing over the water may eventually skirt the Outer Banks of NC toward the end of the period. At this time it appears the instability gradient will remain offshore. ..Jewell.. 12/17/2025 Read more

No watches are valid as of Wed Dec 17 17:30:02 UTC 2025.

No Mesoscale Discussions are in effect as of Wed Dec 17 17:30:02 UTC 2025.

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Wed Dec 17 2025 Valid 171700Z - 181200Z The previous forecast remains on track with only minor expansions made across southeast CO/southwest KS to reflect latest high-res guidance. 16 UTC surface observations show winds beginning to increase along the northern CO Front Range, but the strongest winds are expected later this afternoon (mainly between 20-00 UTC) as the mid-level jet begins to impinge on the northern Rockies. It remains unclear exactly how severe RH reductions will be in the lee of the immediate front range where peak winds are expected. While some guidance shows RH minimums near 20%, morning solutions don't appear to be accurately capturing recent satellite trends with more widespread cloud cover noted in GOES imagery than depicted in recent HRRR/RRFS runs. This continues to limit confidence in the potential for widespread critical fire weather conditions, though localized critical conditions may emerge if sufficient clearing can occur. Regardless, the strong winds coupled with slowly increasing ERC values (near the 70th percentile) should still support a wind-driven fire weather risk. See the previous discussion below for additional details. ..Moore.. 12/17/2025 .PREV DISCUSSION... /ISSUED 1150 PM CST Tue Dec 16 2025/ ...Synopsis... A potent upper trough will move through the Northwest and reach the Plains by Thursday morning. At the surface, a cyclone will deepen in the northern Plains with a trough extending into the central/southern Plains. ...Central/southern High Plains... Strong mid-level winds will be nearly perpendicular to the Rockies. This, coupled with a strong cross-Divide pressure gradient, will foster strong sustained winds and stronger gusts in the immediate lee of the terrain. Sustained 20-30 mph winds will be probable in the terrain-favored areas. A period of wind gusts to 60-70 mph are expected in the lower foothills. Farther east and south, 15-20 mph will become more common. RH will be above elevated criteria in many places, but 15-25% will be possible from Wyoming into Colorado. Farther south, RH will more likely be around 15-20%. With fuels having continued to dry, the strong surface winds will still lead to elevated to locally critical fire weather. ...Piedmont... Dry and modestly breezy conditions appear possible within the region during the afternoon. RH could fall as low as 20-25%, but there is variability within guidance. Winds will generally be light at around 10 mph. Locally elevated conditions are possible, but the duration/spatial extent is too limited and uncertain for highlights. ...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 1022 AM CST Wed Dec 17 2025 Valid 171630Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN IDAHO AND NORTHERN UTAH... ...SUMMARY... While strong to locally severe winds may occur with low-topped convection through early afternoon across parts of southern Idaho and northern Utah, the overall threat for organized severe thunderstorms appears low. ...Interior Northwest and Northern Great Basin/Rockies... A powerful mid-level shortwave trough and associated sub-980 mb surface low will move quickly eastward today across the interior Northwest/northern Rockies and adjacent western Canada. A strong surface cold front will likewise translate east-southeastward over the northern Intermountain/Great Basin region late this morning into the afternoon. Widespread cloud cover remains prevalent ahead of the front across southern ID into northern UT and vicinity, with cool surface temperatures and very limited low-level moisture also present. MUCAPE is expected to remain only barely sufficient to support convection. But, given the enhanced flow at low levels noted on recent VWPs from KCBX/KSFX, it is not entirely out of the question that convectively augmented gusts may exceed the already strong background gradient winds on a localized basis. The Marginal Risk has therefore been maintained for parts of southern ID/northern UT and vicinity, even though the overall threat for organized severe thunderstorms will remain low. ..Gleason/Weinman.. 12/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Wed Dec 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHWEST AND NORTHERN INTERMOUNTAIN REGION... ...SUMMARY... Sporadic severe wind gusts may accompany low-topped convection across parts of the Northwest and northern Intermountain region this morning into midday. ...Northwest/Northern Intermountain region... A progressive/vigorous shortwave trough will continue to modestly amplify and otherwise race east-southeastward from the Washington/British Columbia border vicinity this morning to the northern Plains tonight. Intense deep-tropospheric flow (highlighted by 55-85 kt at 700 mb) will accompany this wave, yielding widespread high winds across much of the Northwest to the northern Great Plains. Low-topped convection, occasionally capable of lightning and semi-organized line segments, will continue in association with the east/southeastward-advancing cold front, with convection potentially expanding by late morning towards the Snake River Plain/Yellowstone vicinity and potentially other parts of the northeast Great Basin by afternoon. Surface-based instability will be very limited, but some convectively enhanced wind gusts may occur. ..Guyer/Lyons.. 12/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Wed Dec 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHWEST AND NORTHERN INTERMOUNTAIN REGION... ...SUMMARY... Sporadic severe wind gusts may accompany low-topped convection across parts of the Northwest and northern Intermountain region this morning into midday. ...Northwest/Northern Intermountain region... A progressive/vigorous shortwave trough will continue to modestly amplify and otherwise race east-southeastward from the Washington/British Columbia border vicinity this morning to the northern Plains tonight. Intense deep-tropospheric flow (highlighted by 55-85 kt at 700 mb) will accompany this wave, yielding widespread high winds across much of the Northwest to the northern Great Plains. Low-topped convection, occasionally capable of lightning and semi-organized line segments, will continue in association with the east/southeastward-advancing cold front, with convection potentially expanding by late morning towards the Snake River Plain/Yellowstone vicinity and potentially other parts of the northeast Great Basin by afternoon. Surface-based instability will be very limited, but some convectively enhanced wind gusts may occur. ..Guyer/Lyons.. 12/17/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0357 AM CST Wed Dec 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Southerly low-level flow will return to the southern Plains on D4/Saturday. This will bring 60sF dewpoints to east Texas and much of Louisiana with weak destabilization anticipated. A few storms may be possible across Louisiana on Saturday night, but shear will be weak. Minimal vertical shear combined with limited forcing and only weak instability will preclude any severe weather threat. Isolated thunderstorm activity is possible from D5/Sunday through the first half of next week from East Texas and Louisiana into the Ozarks and into the Midwest as slight enhancements of the low-level jet promote isentropic ascent. Through this period, low to mid 60s dewpoints will progressively advance farther inland. However, instability should remain weak as mid-level heights build and mid-level temperatures warm. Therefore, despite the inland moisture early next week, severe weather potential remains low due to weak instability, weak forcing, and building heights aloft. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0357 AM CST Wed Dec 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... Southerly low-level flow will return to the southern Plains on D4/Saturday. This will bring 60sF dewpoints to east Texas and much of Louisiana with weak destabilization anticipated. A few storms may be possible across Louisiana on Saturday night, but shear will be weak. Minimal vertical shear combined with limited forcing and only weak instability will preclude any severe weather threat. Isolated thunderstorm activity is possible from D5/Sunday through the first half of next week from East Texas and Louisiana into the Ozarks and into the Midwest as slight enhancements of the low-level jet promote isentropic ascent. Through this period, low to mid 60s dewpoints will progressively advance farther inland. However, instability should remain weak as mid-level heights build and mid-level temperatures warm. Therefore, despite the inland moisture early next week, severe weather potential remains low due to weak instability, weak forcing, and building heights aloft. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0221 AM CST Wed Dec 17 2025 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected along the East Coast Friday morning and in the Pacific Northwest Friday afternoon through Friday night. ...Discussion... A strong cold front will be moving quickly eastward Friday morning with a shallow convective band along the front. A few stronger storms are possible as the front interacts with slightly greater moisture/instability near the coast. However, it is unclear whether storms will intensify before they move offshore. The best potential for a few stronger cells with some gusty winds will be across southeast Virginia and eastern North Carolina. In the wake of this cold front, cool/dry conditions associated with a surface high will bring dry conditions to much of the eastern CONUS. A few isolated thunderstorms will be possible in the Pacific Northwest as temperatures cool aloft. ..Bentley.. 12/17/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CST Wed Dec 17 2025 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTERED OVER KENTUCKY AND TENNESSEE... ...SUMMARY... Isolated damaging wind gusts are possible across portions of the Lower Ohio and Tennessee Valleys on Thursday. ...Synopsis... A strong mid-level jet streak will round the base of the mid-level trough across the central Plains early Thursday and emerge across the Ohio Valley by Thursday afternoon/evening. This trough will continue east and take on a more neutral to perhaps negative tilt by early Friday across the East Coast. A strong (sub 990mb) surface low will move from the Upper Midwest to southern Quebec with a trailing cold front sweeping from the Midwest to the East Coast. ...OH/TN Valleys... The cold front is expected to interact with the richer low-level moisture early in the period across Illinois and Missouri with a shallow line of thunderstorms expected to develop. In addition, some weak elevated instability may develop ahead of this front as cooling mid-level temperatures result in sufficient elevated instability for storms. Low-level instability ahead of the front is expected to remain quite weak (100 to 200 J/kg). A strong frontal circulation should overcome the weak instability and produce sufficient lift for lightning. Any updrafts deep enough to produce lightning, and with minimal inhibition (seemingly around 55F surface dewpoint) may also have at least some isolated damaging wind threat given the 60 to 70 knot low-level jet around 1km. Greater instability is expected south of the TN/MS/AL border where upper 50s to low 60s dewpoints are forecast. However, despite the more favorable thermodynamics, the upper-level forcing will be weaker. Therefore, it is unclear whether the line of storms will continue that far south, and additional convection ahead of the front will likely struggle given the weak lapse rates/minimal heating. ...Eastern Virginia into North Carolina... Strong storms and potential supercells are expected over the warm Gulf Stream waters Thursday evening. Some guidance indicates surface based instability may advect inland across far eastern North Carolina which would allow some of these stronger storms to move inland. Current expectation is for stronger storms and 60+F dewpoints to remain mostly offshore, so no marginal risk will be added. Late in the period, as the cold front crosses the Appalachians, some increase in storm strength is anticipated as mid 50s dewpoints east of the Appalachians provide weak instability to fuel the storms. If more aggressive inland moisture advection occurs, similar to the scenario mentioned above, some marginal damaging wind threat could materialize given the strong wind field. ..Bentley.. 12/17/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Tue Dec 16 2025 Valid 181200Z - 191200Z ...Synopsis... Within a post-cold-front regime, strong northwesterly winds will overspread parts of the central/southern Plains on Thursday. Colder air will filter southward, but this should be lagging behind the front. ...Central/southern Plains... Despite cold air advection through the day, generally clear skies and dry air will promote RH reductions in the 20-30% range. Farther west, into the High Plains, 15-20% RH will be possible. Guidance does show a fair amount of variability with regard to surface temperatures during the afternoon, especially with northern extent. However, sustained winds/gusts will tend to be strongest in the central Plains with weaker winds with southward extent. With fine fuels showing sufficient dryness in some areas and the winds being near or just above critical thresholds, elevated fire weather can be expected from Kansas into North Texas. These conditions may extend farther south and west, but combinations of questionable fuels and duration limit confidence in expanding highlights into these areas. ..Wendt.. 12/17/2025 ...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 1150 PM CST Tue Dec 16 2025 Valid 171200Z - 181200Z ...Synopsis... A potent upper trough will move through the Northwest and reach the Plains by Thursday morning. At the surface, a cyclone will deepen in the northern Plains with a trough extending into the central/southern Plains. ...Central/southern High Plains... Strong mid-level winds will be nearly perpendicular to the Rockies. This, coupled with a strong cross-Divide pressure gradient, will foster strong sustained winds and stronger gusts in the immediate lee of the terrain. Sustained 20-30 mph winds will be probable in the terrain-favored areas. A period of wind gusts to 60-70 mph are expected in the lower foothills. Farther east and south, 15-20 mph will become more common. RH will be above elevated criteria in many places, but 15-25% will be possible from Wyoming into Colorado. Farther south, RH will more likely be around 15-20%. With fuels having continued to dry, the strong surface winds will still lead to elevated to locally critical fire weather. ...Piedmont... Dry and modestly breezy conditions appear possible within the region during the afternoon. RH could fall as low as 20-25%, but there is variability within guidance. Winds will generally be light at around 10 mph. Locally elevated conditions are possible, but the duration/spatial extent is too limited and uncertain for highlights. ..Wendt.. 12/17/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Tue Dec 16 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE NORTHWEST... ...SUMMARY... Sporadic severe gusts may accompany low-topped convection across parts of the Northwest this morning into midday. ...Northwest... A vigorous shortwave trough will move quickly east along the Canadian border from WA to the northern Great Plains by evening. Intense tropospheric flow will accompany this wave, yielding widespread high winds across much of the Northwest to the northern Great Plains. Deep lee surface cyclone over southern AB should reach the Red River Valley of the North. Attendant Pacific cold front will sweep east with a tight pressure gradient in its wake. Low-topped convection may be ongoing at 12Z along the Columbia Basin portion of the front. Most guidance also suggests an increase in low-topped convection should occur towards late morning across parts of the Snake River Plain as the front pushes east. Surface-based instability will remain scant in both regimes with morning temperatures in the 40s to low 50s. Despite the cool temperatures, this may be sufficient for sporadic lightning flashes amid strong large-scale ascent. With very strong surface winds accompanying the front, both regimes could be coincident with severe wind gusts. The bulk of sustained severe wind speeds should become primarily confined along/east of the Rockies in MT to the CO Front Range this afternoon per HREF/REFS guidance. However, potential for severe convective gusts appears too conditional with negligible surface-based buoyancy anticipated. ..Grams/Wendt.. 12/17/2025 Read more

No Mesoscale Discussions are in effect as of Tue Dec 16 23:56:02 UTC 2025.

No watches are valid as of Tue Dec 16 23:56:02 UTC 2025.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0341 PM CST Tue Dec 16 2025 Valid 181200Z - 241200Z Fire weather concerns are expected to emerge across portions of the Plains and southern High Plains through the second-half of the work week and into the upcoming weekend. Latest long-range guidance shows remarkable good agreement in the medium to long-range synoptic regime evolution, depicting a transition from an active zonal flow regime this week/weekend into broad-scale ridging across the south-central CONUS by early next week. This pattern shift will favor rain/snow chances for much of country except the Southwest into much of the southern Plains where rainfall deficits are steadily deepening and fuels are slowly drying. ...D3/Thursday - Central/southern Plains... A strong cyclone is forecast to develop across the northern Plains on D2/Wednesday before shifting into the upper Great Lakes region by late D3/Thursday. A trailing cold front will push southeast across the Plains through the afternoon, reaching the MS Valley by evening. Vigorous low-level cold advection within the post-frontal air mass, coupled with a strong low-level mass response in proximity to the intensifying cyclone, will support widespread 15-25 mph north/northwesterly winds from western KS and northwest OK into MO. While there remains some spread regarding the coverage of the strongest winds, the general guidance consensus is that conditions will be dry/windy enough behind the front to support elevated to critical fire weather conditions over a region with drying fine fuels. ...D4/Friday - Southeast Wyoming... A second upper disturbance is forecast to progress across the northern Rockies early D4/Friday. This will support an intensifying surface low over the northern Plains with an accompanying low-level mass response over the High Plains. The combination of the strengthening low/lee trough and zonal mid-level flow over the terrain will support another downslope wind event in the lee of the Laramie Mountains in southeast WY. Long-range guidance suggests sustained winds of 20-30 mph are possible along with RH minimums in the teens to low 20s. Preceding dry/windy days this week will help precondition fuels and support a fire weather threat on Friday. ...D4/Friday and D5/Saturday - southern Plains... Surface high pressure will quickly shift east into the lower MS Valley by early D4/Friday morning just as a northern High Plains cyclone intensifies. The combination of southwesterly flow on the periphery of the surface high combined with falling surface pressure over the northern/central Plains will induce a breezy and dry return flow regime over portions of TX and OK. The signal for 15-25 mph winds has remained consistent between deterministic solutions over the past 24 hours, and ensemble guidance has begun to show better consensus for 20+ mph winds across northwest TX to northwest OK Friday afternoon. Given the gradual drying trend of fuels and the tendency for guidance to over-forecast RH minimums within these regimes, fire weather concerns appear probable Friday afternoon. Dry/breezy conditions will likely persist across parts of TX on D5/Saturday ahead of a southward moving cold front. Westerly flow emanating out of the southern High Plains will maintain dry conditions, and ensemble guidance hints at wind speeds approaching 20 mph. Uncertainty persists regarding the placement/progression of the cold front by Saturday afternoon, and guidance tends to depict slower frontal intrusions than reality. Because of this, adjustments of the risk probabilities are expected as model consensus continues to improve. ..Moore.. 12/16/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0127 PM CST Tue Dec 16 2025 Valid 162000Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE PACIFIC NORTHWEST... ...SUMMARY... Sporadic severe wind gusts may accompany low-topped convection across parts of the Pacific Northwest tonight into early Wednesday morning. ...20z Update... No changes are needed to the D1 Convective Outlook. See previous discussion for more information. ..Thornton.. 12/16/2025 .PREV DISCUSSION... /ISSUED 1020 AM CST Tue Dec 16 2025/ ...Pacific Northwest... A strong mid-level shortwave trough over the eastern Pacific will amplify today and reach the coastal Pacific Northwest late tonight. This trough will be accompanied by an enhanced deep-layer wind field, with 90-100+ kt winds at 500 mb and around 50-80 kt flow in the lowest 1-3 km AGL. Low-level moisture should also gradually increase tonight ahead of an eastward-advancing cold front. Low-topped convection may accompany the front, initially approaching the WA Coast by late evening, and then more interior areas overnight/early Wednesday. Surface-based buoyancy will remain quite meager due to poor lapse rates aloft and the time of night. Still, rather strong low-level gradient winds will shift from the southwest to west-northwest as the front passes. Sporadic lightning flashes and occasional strong to severe-caliber wind gusts may accompany the passage of this low-topped convective line, with the most intense low-level winds/convective influences expected to peak during the overnight and early morning hours Wednesday. However, it remains quite uncertain if these convectively enhanced winds will be substantially stronger than the background gradient wind field. Therefore, the Marginal Risk has been maintained with no changes. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0127 PM CST Tue Dec 16 2025 Valid 162000Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE PACIFIC NORTHWEST... ...SUMMARY... Sporadic severe wind gusts may accompany low-topped convection across parts of the Pacific Northwest tonight into early Wednesday morning. ...20z Update... No changes are needed to the D1 Convective Outlook. See previous discussion for more information. ..Thornton.. 12/16/2025 .PREV DISCUSSION... /ISSUED 1020 AM CST Tue Dec 16 2025/ ...Pacific Northwest... A strong mid-level shortwave trough over the eastern Pacific will amplify today and reach the coastal Pacific Northwest late tonight. This trough will be accompanied by an enhanced deep-layer wind field, with 90-100+ kt winds at 500 mb and around 50-80 kt flow in the lowest 1-3 km AGL. Low-level moisture should also gradually increase tonight ahead of an eastward-advancing cold front. Low-topped convection may accompany the front, initially approaching the WA Coast by late evening, and then more interior areas overnight/early Wednesday. Surface-based buoyancy will remain quite meager due to poor lapse rates aloft and the time of night. Still, rather strong low-level gradient winds will shift from the southwest to west-northwest as the front passes. Sporadic lightning flashes and occasional strong to severe-caliber wind gusts may accompany the passage of this low-topped convective line, with the most intense low-level winds/convective influences expected to peak during the overnight and early morning hours Wednesday. However, it remains quite uncertain if these convectively enhanced winds will be substantially stronger than the background gradient wind field. Therefore, the Marginal Risk has been maintained with no changes. Read more