Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CST Thu Dec 29 2022 Valid 301200Z - 311200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track, and no changes were needed with this update. ..Weinman.. 12/29/2022 .PREV DISCUSSION... /ISSUED 1149 PM CST Wed Dec 28 2022/ ...Synopsis... The latest in a series of mid/upper-level shortwave troughs is forecast to move across the southern Great Plains on Friday. As this occurs, a weak surface low is forecast to develop across the southern High Plains. Relatively dry and breezy conditions will be possible across parts of eastern NM into west TX on Friday afternoon in response to the developing lee trough/surface low, but with low-level flow generally expected to be weaker and have somewhat less of a downslope component compared to previous days, the potential for more than localized elevated conditions appears limited at this time. ...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 1048 AM CST Thu Dec 29 2022 Valid 291700Z - 301200Z The only change with this update was to expand the Elevated highlights northeastward into west-central and southwest OK. Here, temperatures are climbing into the upper 50s/lower 60s (aided by clearing/thinning high clouds) ahead of a slow-moving cold front. And, additional boundary-layer heating/mixing into a remnant low-level jet (sampled by regional VWP) should support a couple hours of breezy/gusty westerly surface winds amid 15-25 percent RH. Elsewhere, the previous forecast (see below) remains on track. ..Weinman.. 12/29/2022 .PREV DISCUSSION... /ISSUED 1149 PM CST Wed Dec 28 2022/ ...Synopsis... A mid/upper-level shortwave trough is forecast to move from the southern High Plains at the start of the period northeastward toward the Great Lakes region by early Friday morning. In conjunction with this shortwave trough, a surface cyclone is forecast to move from Kansas toward the upper Midwest, as a weakening cold front moves through portions of the southern Plains. ...Northeast NM into the TX Panhandle/South Plains... Seasonably warm overnight temperatures and a residual belt of stronger westerly low-level flow will support the relatively quick development of elevated fire-weather conditions by late morning across northeast NM into the TX Panhandle and parts of the South Plains. Sustained winds of 15-25 mph are expected through early afternoon, as RH values drop into the 20-25% range. Winds are expected to weaken by mid/late afternoon, but may remain sufficient to support elevated conditions through most of the day, with RH potentially falling below 20% for a few hours across parts of the region. ...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 1022 AM CST Thu Dec 29 2022 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ON FRIDAY FROM SOUTHERN LOUISIANA INTO THE CENTRAL GULF COAST REGION.... ...SUMMARY... Isolated damaging gusts are possible on Friday along the central Gulf Coast. An upper trough currently over northwest Mexico will track eastward across south TX into the western Gulf of Mexico on Friday. Southerly low-level winds ahead of the trough will maintain modest influx of moisture, with dewpoints in the low-mid 60s and marginal CAPE values across southern LA and far southern MS/AL. A consensus of 12z model guidance indicates a line of thunderstorms will extend from central LA into the Gulf at the beginning the period. This convection will track eastward into southern MS/AL through the day, and into the western FL panhandle after dark. The main upper support will lift north of this region, while the greatest instability will remain offshore. Nevertheless, a few strong storms are possible, with locally damaging wind gusts or perhaps a tornado or two. ..Hart.. 12/29/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1001 AM CST Thu Dec 29 2022 Valid 291630Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH LATE EVENING FROM EAST TX/WESTERN LA INTO SOUTHERN AR... ...SUMMARY... Isolated damaging gusts, marginally severe hail and a tornado or two are possible mainly this afternoon and tonight, across parts of east/southeast Texas, western/central Louisiana and the Arklatex region. ...East TX/western LA/southern AR this afternoon into tonight... A remnant lee cyclone will move north-northeastward from northeast KS toward WI, in association with a lead shortwave trough. A separate/upstream shortwave trough will progress east-northeastward from TX Big Bend to east TX by the end of the period. A plume of low-level moisture (boundary-layer dewpoints in the mid-upper 60s) will continue to spread inland from the western Gulf of Mexico to east TX/western LA/southern AR through late evening. Isolated thunderstorms are ongoing within this moisture plume near the Sabine River, and additional convection is expected through the day along the moist axis and along/immediately east of a surface trough in TX. The storm environment will be characterized by MLCAPE near 1000 J/kg, with modestly long/curved hodographs (effective bulk shear of 30-40 kt and effective SRH of 100-200 m2/s2). Within the broader bands of convection, some embedded/weak supercell structures are expected, with an attendant threat for isolated wind damage/marginally severe hail and a brief/weak tornado or two later this afternoon through late evening. Overnight, convection will spread eastward in one or more bands across AR and western LA, with somewhat larger buoyancy confined over time to southwest LA. ..Thompson/Lyons.. 12/29/2022 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1240 PM CST Wed Dec 28 2022 Valid 291200Z - 301200Z Short-range guidance consensus depicts clearing skies from northeast NM into the TX Panhandle during the late morning/early afternoon, supporting a corridor of upper 50s surface temperatures and 15-20 percent RH -- aided by continued downslope warming/drying. Here, an initially tight pressure gradient and enhanced westerly flow through the boundary layer should yield 15-20 mph sustained westerly surface winds with locally higher gusts. While surface winds will subside during the late afternoon owing to a weakening pressure gradient and low-level jet, a few hours of strong/gusty winds and low RH atop modestly receptive fuels should favor elevated conditions from northeast NM into the TX Panhandle during the late morning/early afternoon. ..Weinman.. 12/28/2022 .PREV DISCUSSION... /ISSUED 1223 AM CST Wed Dec 28 2022/ ...Synopsis... A passing shortwave will bring breezy westerly flow amid continued locally dry conditions on Thursday. Deterministic models exhibit spread in afternoon relative humidity. HREF ensemble probabilities are around 10-20 percent for localized areas of elevated conditions across portions of the Texas Panhandle Thursday afternoon. Given the low probability of occurrence across a limited region, no areas have been highlighted at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No Mesoscale Discussions are in effect as of Wed Dec 28 18:42:02 UTC 2022.

No watches are valid as of Wed Dec 28 18:42:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CST Wed Dec 28 2022 Valid 291200Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER EAST TEXAS...NORTHERN/WESTERN LOUISIANA AND SOUTHERN/CENTRAL ARKANSAS... ...SUMMARY... Isolated severe thunderstorms are possible on Thursday into Thursday night from east Texas and western Louisiana northward into western Arkansas. ...Synopsis... A mid-level trough will lift northeast across the central Plains and Great Lakes on Thursday as a surface cold front moves east, extending from WI to the TX/OK border vicinity of the Red River by evening. An increase in boundary-layer moisture will continue from the western Gulf Coast northward in advance of the front, with low 50s dew points possible as far north as southern IL. ...Arklatex... Despite substantial cloud cover, steady moisture advection will contribute to MLCAPE by late afternoon ranging from around 500 J/kg over central AR to 1000-1500 J/kg across southeast TX and coastal waters. The more substantial large-scale ascent with the mid-level trough will remain largely north of the risk area, however a glancing influence combined with low-level warm/moist advection should contribute to the initial development of scattered thunderstorms over east TX/northwest LA during the late afternoon. Forecast wind profiles support organized storms with strong/isolated severe wind potential as the primary risk, especially as storms evolve with time into a predominantly linear mode Thursday evening. The severe threat should lessen with time overnight as instability diminishes. ..Bunting.. 12/28/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1000 AM CST Wed Dec 28 2022 Valid 281700Z - 291200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. In particular, the Elevated highlights were expanded northeastward into the northeastern TX Panhandle and northwest OK. Surface observations over the northeastern TX Panhandle already show 20-30 mph sustained southwesterly surface winds (with higher gusts) amid 20-25 percent RH. And, despite increasing cloud coverage from the west, thinner clouds and related boundary-layer heating/mixing will support the east-northeastward expansion of these conditions into northwest OK this afternoon. Elsewhere, an expansive area of elevated conditions remains likely over much of west TX this afternoon, with locally critical meteorological conditions possible from the TX Trans-Pecos into the TX South Plains. ..Weinman.. 12/28/2022 .PREV DISCUSSION... /ISSUED 1222 AM CST Wed Dec 28 2022/ ...Synopsis... An upper-level trough will begin to spread over the southern High Plains on Wednesday as a surface low deepens across Kansas. West to southwest surface gradients will increase across portions of western and central Texas with surface winds around 20-25 mph (gusting 30-40 mph). The driest and windiest conditions look to extend from Trans-Pecos into the Texas South Plains where afternoon relative humidity may drop as low as 15-20 percent. Fuel dryness remains normal to above normal across much of this region, with the exception of the more fine fuels. An Elevated delineation is supported, given the largely unreceptive fuels. ...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 0955 AM CST Wed Dec 28 2022 Valid 281630Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible across the Four Corners today and along the northwest Gulf coast late tonight. ...Synopsis... A progressive shortwave trough will move eastward over the Four Corners today, with the threat for isolated thunderstorms in association with steep midlevel lapse rates and a few hundred J/kg of SBCAPE. Farther east, air mass modification and return flow is underway across the western Gulf of Mexico, in response to lee cyclogenesis across southwest KS. The northwest Gulf coast will likely remain capped until the very end of the period, when low-level moistening and warm advection may become sufficient for isolated/elevated thunderstorms in warm sector confluence bands. ..Thompson/Lyons.. 12/28/2022 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0142 PM CST Tue Dec 27 2022 Valid 272000Z - 281200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The threat for thunderstorms appears too low to warrant an outlook area. ...Discussion... Aside from a couple of recent lightning flashes over the higher terrain of Shasta County in Northern California, and earlier northwest of the San Francisco bay area, no lightning has been observed over the CONUS today. This should largely remain the situation through the end of the period, and thus no changes to the outlook appear necessary at this time. ..Goss.. 12/27/2022 .PREV DISCUSSION... /ISSUED 0957 AM CST Tue Dec 27 2022/ ...Synopsis... A midlevel shortwave trough will progress inland from the Pacific coast to the Great Basin by tonight with widespread precipitation across CA. Observations and model forecast soundings suggest that buoyancy will remain shallow/weak along the northern CA/OR coasts as the cooler midlevel temperatures and steeper low-level lapse rates spread inland, and lightning flashes will be sparse at best. Otherwise, lingering surface ridging along the Gulf/Atlantic coasts will confine any modifying air mass to offshore waters through tonight. Read more

No watches are valid as of Tue Dec 27 19:47:02 UTC 2022.

No Mesoscale Discussions are in effect as of Tue Dec 27 19:47:02 UTC 2022.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Dec 27 2022 Valid 281200Z - 291200Z The Elevated area has been expanded somewhat into the south-central and southeast TX Panhandle based on the latest guidance trends, but otherwise the previous outlook reasoning remains valid. Gusty southwest winds and minimum RH values of 15-25% will support an elevated fire-weather threat from the Trans-Pecos into the TX South Plains and southern Panhandle region. See the previous discussion below for more information. ..Dean.. 12/27/2022 .PREV DISCUSSION... /ISSUED 1137 PM CST Mon Dec 26 2022/ ...Synopsis... For Wednesday, the upper-level trough will eject into the southern High Plains by late afternoon. Southwesterly winds are expected to increase across the region to 15-25 mph, driven by a deepening cyclone in southwestern Kansas. Gust of up to 30-35 mph appear possible given the stronger winds just above the surface. RH values again will be uncertain. However, these scenarios tend to end up drier than most models forecast. That being said, RH of 15-25% is expected during the afternoon. Fine fuels have been able to dry near seasonal norms. Given the winds expected, elevated fire weather concerns are forecast for parts of the Trans Pecos into the Texas South Plains. ...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 1041 AM CST Tue Dec 27 2022 Valid 271700Z - 281200Z The Elevated area has been expanded slightly eastward across southeast CO and northeast NM, but otherwise the previous outlook reasoning remains valid. Westerly downslope winds of 15-20 mph (with higher gusts) combined with minimum RH values of near or below 20% will result in elevated fire-weather conditions for a few hours this afternoon. See the previous discussion below for more information. ..Dean.. 12/27/2022 .PREV DISCUSSION... /ISSUED 1136 PM CST Mon Dec 26 2022/ ...Synopsis... A mid-level jet will approach the Four Corners. Stronger winds aloft will nudge into the High Plains region and promote a deepening lee trough through the day. Downslope winds will increase in the lee of the Sangre de Cristo Mountains. Despite cooler temperatures recently, a general lack of rainfall has allowed fine fuels to dry out in much of the southern High Plains. Winds of 15-20 mph along with higher gusts are possible. Some locally higher winds speeds are higher in terrain-favored areas. RH reductions are a bit uncertain, but local values in the 15-20% range are possible. A focused area of elevated fire weather is expected in parts of southeast Colorado and northeast New Mexico. ...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 1034 AM CST Tue Dec 27 2022 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not forecast across the contiguous United States on Wednesday. ...Synopsis... A longwave mid-level trough will traverse the Intermountain West and eject into the Plains states tomorrow/Wednesday. Multiple mid-level impulses embedded within the broader longwave trough will foster localized ascent in the presence of marginal buoyancy to support isolated thunderstorm development in a couple of regions. First, a mid-level impulse will overspread the Four Corners region, accompanied by cooler temperatures and steep mid-level lapse rates during the afternoon hours, when lightning flashes are most likely to occur. Later at night, a lead impulse ejecting into the Plains will promote a low-level warm-air/moisture advection regime across the lower MS Valley, where isolated thunderstorm development is possible. A lightning flash or two cannot be ruled out along the Pacific Northwest coastline toward the end of the period as another mid-level impulse with cooler mid-level temperatures approaches the region. ..Squitieri.. 12/27/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0957 AM CST Tue Dec 27 2022 Valid 271630Z - 281200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The threat for thunderstorms appears too low to warrant an outlook area. ...Synopsis... A midlevel shortwave trough will progress inland from the Pacific coast to the Great Basin by tonight with widespread precipitation across CA. Observations and model forecast soundings suggest that buoyancy will remain shallow/weak along the northern CA/OR coasts as the cooler midlevel temperatures and steeper low-level lapse rates spread inland, and lightning flashes will be sparse at best. Otherwise, lingering surface ridging along the Gulf/Atlantic coasts will confine any modifying air mass to offshore waters through tonight. ..Thompson/Lyons/Supinie.. 12/27/2022 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0129 PM CST Mon Dec 26 2022 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms may occur across parts of northern California and southwest Oregon tonight. ...Discussion... No changes to the ongoing outlook appear to be required. ..Goss.. 12/26/2022 .PREV DISCUSSION... /ISSUED 0942 AM CST Mon Dec 26 2022/ ...Synopsis... An initial shortwave trough is moving inland over northwest WA this morning, while a stronger/upstream trough will approach the northern CA/OR coasts by 27/06-12z. Colder midlevel temperatures and steeper low-midlevel lapse rates will accompany the overnight trough as the primary baroclinic zone moves inland, and a few lightning flashes will become possible in the 06-12z time frame. Though wind profiles will be strong, very weak buoyancy will tend to limit any damaging-wind threat near the coast. Read more

No watches are valid as of Mon Dec 26 19:34:01 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Dec 26 19:34:01 UTC 2022.