Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0955 AM CST Wed Jan 18 2023 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN PLAINS... The forecast remains on track, and no changes were needed to the ongoing Elevated or Critical areas. Visible satellite imagery late this morning shows clear skies over much of western/central TX and rapidly eroding clouds along the eastern edge of the Critical area (in the wake of the cold front). As a midlevel jet/dry-slot (evident in water vapor imagery) continues overspreading the risk area, efficient boundary-layer heating/mixing and strengthening westerly surface winds (sustained 25-30 mph with 35-40 mph gusts) are expected. These conditions will favor an expansive area of critical conditions across much of western and central TX this afternoon. For additional details, see the previous discussion below. ..Weinman.. 01/18/2023 .PREV DISCUSSION... /ISSUED 1258 AM CST Wed Jan 18 2023/ ...Synopsis... A strong mid-level trough will amplify as it crosses the central Plains today. A surface low will move from the TX/OK Panhandle into Missouri today with a cold front moving across eastern Oklahoma and Texas. In the wake of this cold front, dry and breezy conditions will develop as deep mixing commences beneath a very strong mid-level jet. Sustained winds of 25 to 30 mph are expected with relative humidity of 15 to 20 percent. ERC values are now around the 70-80th percentile and fine fuels remain dry and dormant. Therefore, a threat for large fires will exist across much of West and central Texas today. Dry and windy conditions will persist farther west into New Mexico, but temperatures will drop into the 40s across this region which will limit the fire weather threat. ...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 0955 AM CST Wed Jan 18 2023 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN PLAINS... The forecast remains on track, and no changes were needed to the ongoing Elevated or Critical areas. Visible satellite imagery late this morning shows clear skies over much of western/central TX and rapidly eroding clouds along the eastern edge of the Critical area (in the wake of the cold front). As a midlevel jet/dry-slot (evident in water vapor imagery) continues overspreading the risk area, efficient boundary-layer heating/mixing and strengthening westerly surface winds (sustained 25-30 mph with 35-40 mph gusts) are expected. These conditions will favor an expansive area of critical conditions across much of western and central TX this afternoon. For additional details, see the previous discussion below. ..Weinman.. 01/18/2023 .PREV DISCUSSION... /ISSUED 1258 AM CST Wed Jan 18 2023/ ...Synopsis... A strong mid-level trough will amplify as it crosses the central Plains today. A surface low will move from the TX/OK Panhandle into Missouri today with a cold front moving across eastern Oklahoma and Texas. In the wake of this cold front, dry and breezy conditions will develop as deep mixing commences beneath a very strong mid-level jet. Sustained winds of 25 to 30 mph are expected with relative humidity of 15 to 20 percent. ERC values are now around the 70-80th percentile and fine fuels remain dry and dormant. Therefore, a threat for large fires will exist across much of West and central Texas today. Dry and windy conditions will persist farther west into New Mexico, but temperatures will drop into the 40s across this region which will limit the fire weather threat. ...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 1201 PM CST Tue Jan 17 2023 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN PLAINS... Only minor adjustments were made to the outlook based on the latest high-resolution guidance consensus. In particular, the Critical highlights were expanded on the eastern and western edges slightly, where any early-day precipitation should be limited per the latest HREF QPF fields. With critical meteorological conditions expected over these areas, the expansion is warranted. Elsewhere, the previous forecast (see below) remains on track, with an expansive area of critical conditions expected over much of central and northwest TX. ..Weinman.. 01/17/2023 .PREV DISCUSSION... /ISSUED 0146 AM CST Tue Jan 17 2023/ ...Synopsis... A mid-level trough will amplify as it moves into the Plains on Wednesday. A lee cyclone will deepen across southeast Colorado and move along the Oklahoma/Kansas border during the day. The tightening pressure gradient will lead to strengthening surface winds across much of the southern Plains. The strongest winds are expected in the wake of the cold front, where deeper mixing is expected. Therefore, some stronger mid-level flow will reach the surface with sustained winds of 25 to 30 mph expected. In addition, this region is where the lowest relative humidity is expected, particularly directly behind the cold front where temperatures will remain somewhat higher initially. Additionally, the eastern extent of the threat will likely be mitigated by some precipitation which is expected Tuesday night/Wednesday morning. The eastern Elevated/Critical delineation is currently where wetting rain is most likely. However, this will likely change as the precipitation forecast becomes more clear. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Jan 17 18:03:02 UTC 2023.

No Mesoscale Discussions are in effect as of Tue Jan 17 18:03:02 UTC 2023.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CST Tue Jan 17 2023 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE MID-SOUTH AND SOUTHEAST... ...SUMMARY... Severe thunderstorms are possible from far east Texas and the Lower Mississippi Valley into the Tennessee and Lower Ohio Valleys on Wednesday. ...Synopsis... An upper-level trough will be in the process of ejecting into the southern Plains early Wednesday. This feature is expected to strengthen through the period. A mid-level jet of near 100 kts is expected to evolve within parts of the Mid-South and into the lower Ohio Valley. At the surface, a low pressure system will initially be located in southwestern Kansas. This low will move northeastward along with its parent trough. A secondary, weaker surface low is also forecast to develop in the lower Ohio Valley later in the day. A Pacific cold front will generally be the focus for convection across the Mid-South into the Southeast. Low to mid 60s F dewpoints are expected to advect northward ahead of the boundary as wind fields intensify. ...East TX...Lower/Mid MS Valley...TN Valley...Southeast... Some early convection appears possible in parts of the region, though modest capping should limit the overall extent of this early activity. Some guidance does depict more isolated/cellular activity ahead of the front by late morning. However, stronger cooling aloft will be offset from this activity and updrafts may struggle to maintain intensity. By the afternoon, stronger forcing and some surface heating will allow stronger storms to develop along the cold front. Lapse rates aloft are expected to be moderate (around 7-7.5 C/km) which will limit overall buoyancy to 500-1000 J/kg in most areas. Strong shear will support organized storms. Wind damage is expected to be the primary hazard, but a couple tornadoes also appear possible given the enlarged low-level hodographs present. Areas of eastern Arkansas/northwest Mississippi/western Tennessee will have the best overlap of buoyancy and forcing which could lead to a local maximum in wind damage potential. ...Lower Ohio Valley... Despite more limited instability/buoyancy, very strong wind fields at low/mid-levels will promote wind damage potential with strongly forced convection. The risk for wind damage will quickly drop off with northward/eastward extent. ...Parts of eastern Kansas... Very cold temperatures aloft will be present beneath the upper low. Moisture is expected to be quite limited and storm initiation is not certain. However, profiles would support some risk for at least small hail if convection can develop. ..Wendt.. 01/17/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1022 AM CST Tue Jan 17 2023 Valid 171630Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast through tonight. ...Discussion... A shortwave trough over the Lower CO Valley will deepen as it moves east across the southern Rockies into the southern/central High Plains by early morning, with a lee surface cyclone anchored over southeast CO before shifting into southwest KS late. Isolated thunderstorms will be possible this afternoon/evening within the zone of ascent preceding the shortwave trough, mainly over the Four Corners area. This regime will spread into the central Great Plains tonight, where scant elevated buoyancy should support sporadic lightning activity. Farther southeast, low-level warm theta-e advection should support elevated thunder potential late in the period in the eastern OK/northeast TX/western AR vicinity. An increasingly elongated, straight-line hodograph within the cloud-bearing layer does yield concern for hail production. While small hail looks plausible, meager buoyancy through 12Z will mitigate a severe hail highlight. ..Grams/Lyons.. 01/17/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1001 AM CST Tue Jan 17 2023 Valid 171700Z - 181200Z ...NO CRITICAL AREAS... While fire-weather concerns are generally low for today, at least locally elevated conditions are possible over the TX Trans-Pecos region, with a focus over the Big Bend this afternoon. Here, low/midlevel west-southwesterly flow will gradually strengthen in advance of a large-scale trough -- favoring downslope warming/drying and 15-20 percent RH despite lingering cloud coverage. These dry conditions, coupled with 15-20 mph southwesterly surface winds in the vicinity of a developing lee trough, will support locally elevated conditions given modestly dry fuels. However, these conditions appear too marginal/localized for Elevated highlights. ..Weinman.. 01/17/2023 .PREV DISCUSSION... /ISSUED 0144 AM CST Tue Jan 17 2023/ ...Synopsis... Cool/moist conditions will prevail across the CONUS on Tuesday which will keep fire weather concerns minimal. ...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 0143 PM CST Mon Jan 16 2023 Valid 162000Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN IA INTO NORTHWEST IL AND OVER THE SOUTHERN GREAT BASIN... ...SUMMARY... A brief tornado or two and marginally severe hail will be possible in a portion of eastern Iowa to northwest Illinois through sunset. Marginally severe hail and wind will also be possible over the southern Great Basin into early evening. ...20z Update... Only minor changes to the 10 percent general thunder line in the Midwest have been made with the 20z Update. A low potential for a low-topped supercell will continue across east-central IA into northwest IL the next 2-3 hours. Current convection is occurring ahead of the axis of modest surface-based instability. However, additional cells may develop within narrow wedge of instability with time. The risk will rapidly diminish beyond 23-00z as boundary-layer cooling ensues. Additional isolated strong storms may produce sporadic hail and strong gusts across parts of the southern Great Basin into this evening. ..Leitman.. 01/16/2023 .PREV DISCUSSION... /ISSUED 1026 AM CST Mon Jan 16 2023/ ...Eastern IA and northwest IL... Favorable wind profiles for low-topped supercells will be present in the southeast quadrant of a 994-mb surface cyclone tracking from southwest to northeast IA. Surface temperatures have warmed into the mid 50s to low 60s in a confined corridor centered on LWD-CDJ before broadening across central MO, with relatively ample insolation beneath the mid-level dry slot. The 12Z NAM and most HREF members appear much too cool within the thermal axis compared to 16Z observations. The RAP/HRRR-based guidance appear closer to reality but may be a bit too moist given an even narrower corridor of low 50s surface dew points from southwest to north-central MO. But further mixing and poleward moisture advection may be just enough, given the mid-level cold pocket of -22 to -24 C at 500 mb, to support meager MLCAPE approaching 500 J/kg towards mid-afternoon. While it is plausible that convection may fail to adequately intensify this afternoon, observational trends along with HRRR/RRFS guidance suggest the threat for a couple brief tornadoes and marginally severe hail is large enough to warrant low severe probabilities. Convection will subside quickly after sunset as it outpaces the narrow plume of weak surface-based instability. ...Southern Great Basin... A shortwave impulse centered over central CA will move east into the southern Great Basin through this evening. Ascent ahead of this wave appears favorably timed with the diurnal heating cycle to support at least isolated thunderstorm development this afternoon. However, abundant cloud coverage suggests surface warming will be limited. Nevertheless, the presence of surface dew points in the 40s should still yield meager buoyancy with MLCAPE of 250-500 J/kg. Combined with effective shear near 40 kts, the setup could support a couple updrafts with weak mid-level rotation. Marginally severe hail and wind appear to be the primary threats. Read more

No watches are valid as of Mon Jan 16 19:47:02 UTC 2023.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1035 AM CST Mon Jan 16 2023 Valid 171200Z - 181200Z ...NO CRITICAL AREAS... The previous forecast reasoning (see below) remains the same, and no changes were needed with this update. ..Weinman.. 01/16/2023 .PREV DISCUSSION... /ISSUED 0109 AM CST Mon Jan 16 2023/ ...Synopsis... A lee cyclone is expected to form across southeast Colorado on Tuesday afternoon. This will lead to strengthening winds across the southwest and southern High Plains. However, relative humidity is expected to remain above 30 percent across the region except for near the Rio Grande in the Big Bend. Therefore, fire weather concerns should be minimal. ...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 1034 AM CST Mon Jan 16 2023 Valid 161700Z - 171200Z The Elevated area was expanded southward into central TX, where confidence in the development of around 25 percent minimum RH has increased for this afternoon. These RH reductions should be aided by gradually strengthening downslope flow off the southern Rockies and at least modest boundary-layer mixing into dry air evident in the 1-3-km layer (sampled by the observed 12Z FWD sounding and latest DAL ACARS soundings). Gradually veering surface winds and increasing temperatures over the area are indicating the onset of this mixing. With 30-40 kt of flow also sampled in the lowest 3 km, breezy/gusty westerly surface winds are expected amid the low RH during peak heating. Given dry fuels across the area, elevated conditions are anticipated. ..Weinman.. 01/16/2023 .PREV DISCUSSION... /ISSUED 0107 AM CST Mon Jan 16 2023/ ...Synopsis... Strong westerly flow will occur across a large portion of the southern Plains today in the wake of a cold front as a surface low moves into the Midwest. The strongest winds are expected from southeast New Mexico to central Texas beneath the strongest mid-level flow. However, some moisture will remain across this region and therefore, low relative humidity is not expected. Farther north, a drier airmass is expected, particularly where downslope flow is most prominent. Therefore, a narrow area of overlap between dry and breezy conditions is expected near the Red River where Elevated fire weather concerns are anticipated. ...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 1029 AM CST Mon Jan 16 2023 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not currently expected on Tuesday. ...Synopsis... An upper trough over the Southwest will pivot east to the central High Plains and southern Rockies vicinity by Wednesday morning. Cold midlevel temperatures and moderate southwesterly deep-layer flow will support weak elevated instability and a few lightning flashes will be possible across the Four Corners region. This elevated instability will spread east into portions of the central High Plains overnight atop a sub-freezing boundary-layer. A flash or two could accompany winter precipitation across parts of southwest NE and northwest KS in an area of strong ascent Tuesday night into early Wednesday. However, the probability of thunder with this activity is too low to include a 10 percent general thunder delineation. Further east, an upper ridge will slide east toward the MS Valley and southerly low-level flow will bring Gulf moisture northward across coastal and eastern TX into the central Gulf coast vicinity, especially overnight into Wednesday morning. While increasing boundary-layer moisture will aid in weak instability, warm midlevel temperatures appear to limit convective potential through early Wednesday morning. Enough elevated instability and large-scale forcing may exist near a warm front across northern OK to produce a couple of lightning flashes the last hour or two of the period, but probabilities are too low to include a 10 percent general thunder delineation. ..Leitman.. 01/16/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1026 AM CST Mon Jan 16 2023 Valid 161630Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS EASTERN IA...NORTHWEST IL...AND THE SOUTHERN GREAT BASIN... ...SUMMARY... A couple brief tornadoes and marginally severe hail will be possible in a portion of eastern Iowa to northwest Illinois through sunset. Marginally severe hail and wind will also be possible over the southern Great Basin this afternoon into early evening. ...Eastern IA and northwest IL... Favorable wind profiles for low-topped supercells will be present in the southeast quadrant of a 994-mb surface cyclone tracking from southwest to northeast IA. Surface temperatures have warmed into the mid 50s to low 60s in a confined corridor centered on LWD-CDJ before broadening across central MO, with relatively ample insolation beneath the mid-level dry slot. The 12Z NAM and most HREF members appear much too cool within the thermal axis compared to 16Z observations. The RAP/HRRR-based guidance appear closer to reality but may be a bit too moist given an even narrower corridor of low 50s surface dew points from southwest to north-central MO. But further mixing and poleward moisture advection may be just enough, given the mid-level cold pocket of -22 to -24 C at 500 mb, to support meager MLCAPE approaching 500 J/kg towards mid-afternoon. While it is plausible that convection may fail to adequately intensify this afternoon, observational trends along with HRRR/RRFS guidance suggest the threat for a couple brief tornadoes and marginally severe hail is large enough to warrant low severe probabilities. Convection will subside quickly after sunset as it outpaces the narrow plume of weak surface-based instability. ...Southern Great Basin... A shortwave impulse centered over central CA will move east into the southern Great Basin through this evening. Ascent ahead of this wave appears favorably timed with the diurnal heating cycle to support at least isolated thunderstorm development this afternoon. However, abundant cloud coverage suggests surface warming will be limited. Nevertheless, the presence of surface dew points in the 40s should still yield meager buoyancy with MLCAPE of 250-500 J/kg. Combined with effective shear near 40 kts, the setup could support a couple updrafts with weak mid-level rotation. Marginally severe hail and wind appear to be the primary threats. ..Grams/Wendt.. 01/16/2023 Read more

MD 0066 CONCERNING WINTER MIXED PRECIPITATION FOR PARTS OF DOWNEAST INTO NORTHERN MAINE
Mesoscale Discussion 0066 NWS Storm Prediction Center Norman OK 0949 AM CST Mon Jan 16 2023 Areas affected...Parts of Downeast into northern Maine Concerning...Winter mixed precipitation Valid 161549Z - 162045Z SUMMARY...A mixture of sleet and freezing rain is expected through much of today across parts of eastern/northern Maine. DISCUSSION...A slow moving upper-level low should continue northeast today. A broad area of precipitation is noted in parts of Downeast/mid-coast Maine. This area of precipitation is moving northwestward and will eventually impact parts of the Highlands and northern Maine. Sleet and freezing rain has already been reported. With favorable surface trajectories from the northeast/north, cold air at the surface should remain for most areas through the day. The observed 12Z CAR sounding showed a warm nose at near 800 mb and model forecast soundings show this profile structure generally persisting. A mixture of primarily sleet and freezing rain is expected. Snow is also possible and will be more favored with northern extent. Temperatures in Downeast Maine are nearing freezing and other areas near the coast may do so as well. A transition to rain is possible for these southernmost areas later today. Precipitation should eventually diminish in coverage as the low continues eastward and short-wave ridging aloft builds in by this evening. ..Wendt.. 01/16/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX... LAT...LON 47276789 45376727 44946727 44526854 44456943 44836986 45566987 47196885 47226835 47276789 Read more

No watches are valid as of Sun Jan 15 19:42:02 UTC 2023.

No Mesoscale Discussions are in effect as of Sun Jan 15 19:42:02 UTC 2023.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0137 PM CST Sun Jan 15 2023 Valid 152000Z - 161200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast through tonight. ...20z Update... The previous outlook remains on track and no changes are needed with the 20z update. See previous discussion below for details. ..Leitman.. 01/15/2023 .PREV DISCUSSION... /ISSUED 1019 AM CST Sun Jan 15 2023/ ...Discussion... A quiet pattern for lightning production is expected to persist through tonight, with thunderstorm probabilities appearing to be less than 10 percent. A lightning flash or two is possible this afternoon in lower elevations around the Four Corners area attendant to a shortwave trough ejecting towards the southern Rockies. Amplification of this wave is anticipated tonight as it ejects across the central Great Plains towards the Lower MO Valley. Given the poor low-level moisture sampled by 12Z soundings this morning over the central states to the western Gulf Coast, elevated thunder potential in the warm conveyor region ahead of the wave will likely hold off until after 12Z. Low-topped convection will also redevelop tonight ahead of yet another shortwave trough impinging on the central CA coast. Instability is expected to remain negligible through early morning and casts doubt on lightning occurring along the coast prior to 12Z. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1043 AM CST Sun Jan 15 2023 Valid 161200Z - 171200Z A small Elevated area was introduced from the southeastern TX Panhandle east-southeastward across parts of southwest OK and northwest TX. Through this corridor, efficient diurnal heating and continued strong downslope-flow trajectories should allow temperatures to warm into the mid/upper 60s to lower 70s -- despite weak low/mid-level cold air advection behind the front. With increased confidence in these temperatures supporting 20-25 percent RH amid 20 mph sustained westerly surface winds, the Elevated highlights are warranted -- especially with fine fuels being further conditioned today/Sunday. ..Weinman.. 01/15/2023 .PREV DISCUSSION... /ISSUED 0157 AM CST Sun Jan 15 2023/ ...Synopsis... On Monday, the mid-level trough and surface cyclone will move east into the Midwest. In the wake of this system, some gusty westerly winds are expected across the central and southern Plains. However, cool temperatures will arrive behind the cold front and keep relative humidity too high to support a significant fire weather threat. Elsewhere, a combination of moist or cool conditions will preclude any fire weather concerns. ...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 Sun Jan 15 2023 Valid 151700Z - 161200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN AND CENTRAL HIGH PLAINS... The forecast remains on track, and only minor adjustments were made to the ongoing Elevated and Critical areas based on the latest observations and high-resolution guidance. As expected, widespread mid/high-level clouds have stunted boundary-layer heating/mixing over the risk area thus far. However, strengthening downslope flow and at least pockets of heating amid cloud breaks should still yield a few hours of 15-20 percent RH with strong/gusty surface winds this afternoon. ..Weinman.. 01/15/2023 .PREV DISCUSSION... /ISSUED 0156 AM CST Sun Jan 15 2023/ ...Synopsis... As a mid-level trough advances across the Plains today, strong lee cyclogenesis is expected across eastern Colorado/western Kansas. This deepening cyclone will result in a tight pressure gradient and strong winds across much of the central and southern High Plains. The strongest winds are expected from far west Texas into the Texas Panhandle and southwest Kansas where deep mixing is anticipated. This will result in some stronger flow mixing to the surface and increasing sustained winds to 25 to 30 mph. In addition, dry conditions will be in place with relative humidity around 15 percent. Large fuels are still somewhat moist across this region, but fine fuels are dormant and there has been minimal precipitation in the past few weeks. Therefore, fine fuels should be sufficiently dry to support large fire potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more