Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1106 AM CST Mon Dec 19 2022 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms will be possible on Tuesday from the central Gulf Coast to Florida. No severe weather is expected. ...Synopsis... A shortwave trough will weaken as it moves east across the Gulf Coast, with a surface low over the northern Gulf of Mexico. Forecast soundings indicate only weak elevated instability over land, and a few thunderstorms may occur within the larger-scale area of precipitation from southeast Louisiana into Florida. Storms may approach the west Coast of Florida overnight, but the surface air mass will remain relatively cool, and severe storms are unlikely. ..Jewell.. 12/19/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Mon Dec 19 2022 Valid 191630Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms should develop and spread eastward across the Gulf Coastal Plain from south Texas to near Mobile. Though small hail is possible, organized severe weather still appears unlikely over land. ...Synopsis... Mid-morning regional radar mosaics show a broad region of elevated convection across the TX coastal plain into central LA driven primarily by deep isentropic ascent in the 925-850 mb layer. Along the immediate TX Gulf Coast, surface observations suggest a small zone of warm/moist air (temperatures and dewpoint in the mid 60s) is in place that is supportive of surface-based convection. However, this air mass is expected to largely remain offshore over the next 24 hours as a weak surface low, currently off the Corpus Christi coast, translates east/northeast through the day. The broad zone of precipitation across east TX/LA will reinforce the coastal baroclinic zone, limiting the potential for surface-based buoyancy over land. Given somewhat strong speed shear in the 3-6 km layer, organized elevated convection is possible across portions of the TX coastal plain, mostly likely during the 17-20 UTC period when storm modes are most likely to be discrete before eventual upscale growth/increasing storm interactions within the warm advection regime. Small, sub-severe hail is possible with these storms, but the potential for 1+ inch hail appears sufficiently limited to withhold probabilities. ..Moore/Grams.. 12/19/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0958 AM CST Mon Dec 19 2022 Valid 191700Z - 201200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes or additions made. Please see the previous forecast below for more details. ..Squitieri.. 12/19/2022 .PREV DISCUSSION... /ISSUED 0108 AM CST Mon Dec 19 2022/ ...Synopsis... Broad/enhanced west-northwesterly flow aloft will encompass the western CONUS in the wake of a departing midlevel trough. In the low-levels, a remnant lee cyclone will meander southward and weaken over the southern High Plains. Along the southern periphery of the surface cyclone, breezy west-northwesterly surface winds and 15-20 percent RH are expected from the southern Rockies into the southern High Plains. While locally elevated conditions are possible here during the afternoon, cool surface temperatures and marginal fuels should generally limit the fire-weather threat. ...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 Sun Dec 18 2022 Valid 182000Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated to scattered thunderstorms are expected overnight into early Monday morning across the Texas and Louisiana Gulf Coast. Little change was made to the previous outlook except to remove thunder chances from southern Florida given continued drying from the north. Otherwise, scattered elevated convection is expected overnight across parts of Texas as warm advection increases in advance of the shortwave trough. ..Jewell.. 12/18/2022 .PREV DISCUSSION... /ISSUED 1007 AM CST Sun Dec 18 2022/ ...Synopsis... Morning satellite imagery and surface observations show a cold front slowly pushing south across south FL. This boundary will continue to focus thunderstorm activity through the day amid modest buoyancy and minimal inhibition (as sampled by the 12 UTC KEY sounding). 30-40 knot mid-level winds may allow for transient storm organization, but multicellular storm mode and weak forcing for ascent will limit the severe threat. To the west, dry conditions are noted along the TX Gulf Coast with dewpoints in the low to mid 50s. Some degree of moistening of the continental air mass is apparent over the western Gulf in visible imagery, and additional moistening is expected as southerly low-level winds increase in response to an approaching shortwave trough (currently over southern AZ). The combination of low/mid-level moistening and increasing isentropic ascent will promote isolated to scattered shower/thunderstorm development after 03 UTC tonight. While most convection is expected to be elevated in nature, more robust surface-based thunderstorms are possible along the immediate TX coast where dewpoints in the low/mid 60s are probable and effective shear values could reach upwards of 40-50 knots. Ensemble guidance suggests this moisture will largely remain over coastal areas, limiting the potential for strong/severe storms over land. Read more

No watches are valid as of Sun Dec 18 19:32:02 UTC 2022.

No Mesoscale Discussions are in effect as of Sun Dec 18 19:32:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1107 AM CST Sun Dec 18 2022 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered storms will develop throughout the day on Monday over eastern Texas, and spread into Louisiana and southern Mississippi through Tuesday morning. Small hail may occur, but severe storms are not anticipated. ...Synopsis... A positive-tilt shortwave trough will move eastward across the southern Plains into the lower MS Valley, with a weak surface low developing over the northwest Gulf of Mexico. A surface high will remain over much of the East, and this will result in little to no surface moisture return. Increasing southerly winds above the surface will result in theta-e advection from TX into the lower MS Valley, with lift resulting in widespread precipitation. Elevated instability will favor scattered thunderstorms by midday over eastern TX, then into LA and southern MS overnight. Forecast soundings show maximum MUCAPE of 500-1000 J/kg may develop over eastern TX and LA, along with effective deep shear of 20-40 kt, depending on parcel levels. This may enhance effective-layer storm relative inflow, and possibly support small hail. A cool sub-cloud layer may also minimize melting, but at this time the overall severe threat appears low with numerous competing storms expected. ..Jewell.. 12/18/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1007 AM CST Sun Dec 18 2022 Valid 181630Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will decrease in coverage across south Florida and the Keys through the afternoon. Isolated to scattered thunderstorms are expected overnight into early Monday morning across the Texas and Louisiana Gulf Coast. ...Synopsis... Morning satellite imagery and surface observations show a cold front slowly pushing south across south FL. This boundary will continue to focus thunderstorm activity through the day amid modest buoyancy and minimal inhibition (as sampled by the 12 UTC KEY sounding). 30-40 knot mid-level winds may allow for transient storm organization, but multicellular storm mode and weak forcing for ascent will limit the severe threat. To the west, dry conditions are noted along the TX Gulf Coast with dewpoints in the low to mid 50s. Some degree of moistening of the continental air mass is apparent over the western Gulf in visible imagery, and additional moistening is expected as southerly low-level winds increase in response to an approaching shortwave trough (currently over southern AZ). The combination of low/mid-level moistening and increasing isentropic ascent will promote isolated to scattered shower/thunderstorm development after 03 UTC tonight. While most convection is expected to be elevated in nature, more robust surface-based thunderstorms are possible along the immediate TX coast where dewpoints in the low/mid 60s are probable and effective shear values could reach upwards of 40-50 knots. Ensemble guidance suggests this moisture will largely remain over coastal areas, limiting the potential for strong/severe storms over land. ..Moore/Grams.. 12/18/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1004 AM CST Sun Dec 18 2022 Valid 181700Z - 191200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track. ..Squitieri.. 12/18/2022 .PREV DISCUSSION... /ISSUED 0136 AM CST Sun Dec 18 2022/ ...Synopsis... A southern-stream shortwave trough accompanied by enhanced southwesterly midlevel flow will overspread the southern/central Rockies, promoting lee cyclogenesis near southeastern CO. In response, breezy/gusty southerly surface winds will develop amid 15-25 percent RH over parts of the central and southern High Plains during the afternoon. However, cool surface temperatures and marginal fuels should generally temper the fire-weather threat. ...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 0125 PM CST Sat Dec 17 2022 Valid 172000Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few weak thunderstorms are possible today and tonight over parts of south Florida and the Keys. ...South FL... Heating continues south of a stalled front with a moist, uncapped air mass but little in the way of convergence. However, continued heating may eventually lead to isolated thunderstorms, but weak winds below 700 mb along with poor lapse rates should preclude any severe potential despite strong winds above 500 mb. ..Jewell.. 12/17/2022 .PREV DISCUSSION... /ISSUED 0947 AM CST Sat Dec 17 2022/ ...Synopsis... Recent objective surface analyses and maritime observations show a weak surface low over the central Gulf embedded along a stalled frontal boundary. This feature, likely induced by weak ascent within the right entrance region of the mid/upper-level jet over the south-central CONUS, is expected to propagate east/southeast over the next 24 hours. Thunderstorm development appears probable near and ahead of the low along the residual boundary as it retreats north as a weak warm front over the Keys and south FL through the afternoon. Increasing low-level saturation within the warm frontal zone overlaid with glancing ascent from the passage of the upper-level trough may sustain convection into the overnight hours. Although deep-layer flow and surface-based buoyancy will be adequate for 30-40 knots of effective bulk shear, weakness in the lapse rate profile near 600-650 mb will likely modulate updraft intensities. Instances of small hail and strong wind gusts are possible, but the overall severe threat remains too low for probabilities. Read more

No watches are valid as of Sat Dec 17 19:30:02 UTC 2022.

No Mesoscale Discussions are in effect as of Sat Dec 17 19:30:02 UTC 2022.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1228 PM CST Sat Dec 17 2022 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... No changes have been made to the outlook; see the previous discussion below for more details. ..Dean.. 12/17/2022 .PREV DISCUSSION... /ISSUED 0134 AM CST Sat Dec 17 2022/ ...Synopsis... A southern-stream shortwave trough accompanied by enhanced southwesterly midlevel flow will cross the southern/central Rockies, promoting lee cyclogenesis over southeast CO. In response, breezy southerly surface winds will overspread the central/southern High Plains -- where 20-25 percent minimum RH is possible. While this would normally result in locally elevated conditions, cool surface temperatures and marginally receptive fuels should generally limit the fire-weather threat. ...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 1102 AM CST Sat Dec 17 2022 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few weak thunderstorms are possible Sunday night across parts of southern and southeastern Texas. Severe storms are unlikely. ...Synopsis... A cool and stable pattern will persist for most of the CONUS on Sunday due to high pressure over the central and eastern states. However, a shortwave trough will move from the Southwest into the southern Plains, and will induce low-level moisture return across the western Gulf of Mexico. While the surface air mass over land will remain stable, increasing southerly winds near 850 mb will result in warm advection and ascent, with elevated CAPE sufficient for thunderstorms mainly after 06Z from TX into LA. Elsewhere, very sparse convection with lightning may exist over parts of far southern FL and the Keys during the day, but increasing winds out of the north will provide gradual drying. ..Jewell.. 12/17/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0953 AM CST Sat Dec 17 2022 Valid 171700Z - 181200Z ...NO CRITICAL AREAS... No changes have been made to the outlook; see the previous discussion below for more information. ..Dean.. 12/17/2022 .PREV DISCUSSION... /ISSUED 0134 AM CST Sat Dec 17 2022/ ...Synopsis... Broad/enhanced west-northwesterly flow aloft will extend from the Northwest into the Great Plains, while a southern-stream shortwave trough tracks eastward across southern CA. This will result in the weakening of surface high pressure centered over the Great Basin, though modest offshore flow will persist across southern CA. While breezy/gusty surface winds are expected primarily across parts of Los Angeles and Ventura Counties, these winds will only briefly overlap low RH. Given the limited wind/RH overlap and marginally receptive fuels, Elevated highlights have been withheld. ...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 0947 AM CST Sat Dec 17 2022 Valid 171630Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible today and tonight over parts of south Florida and the Keys. Organized severe weather appears unlikely. ...Synopsis... Recent objective surface analyses and maritime observations show a weak surface low over the central Gulf embedded along a stalled frontal boundary. This feature, likely induced by weak ascent within the right entrance region of the mid/upper-level jet over the south-central CONUS, is expected to propagate east/southeast over the next 24 hours. Thunderstorm development appears probable near and ahead of the low along the residual boundary as it retreats north as a weak warm front over the Keys and south FL through the afternoon. Increasing low-level saturation within the warm frontal zone overlaid with glancing ascent from the passage of the upper-level trough may sustain convection into the overnight hours. Although deep-layer flow and surface-based buoyancy will be adequate for 30-40 knots of effective bulk shear, weakness in the lapse rate profile near 600-650 mb will likely modulate updraft intensities. Instances of small hail and strong wind gusts are possible, but the overall severe threat remains too low for probabilities. ..Moore/Grams.. 12/17/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0947 AM CST Sat Dec 17 2022 Valid 171630Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible today and tonight over parts of south Florida and the Keys. Organized severe weather appears unlikely. ...Synopsis... Recent objective surface analyses and maritime observations show a weak surface low over the central Gulf embedded along a stalled frontal boundary. This feature, likely induced by weak ascent within the right entrance region of the mid/upper-level jet over the south-central CONUS, is expected to propagate east/southeast over the next 24 hours. Thunderstorm development appears probable near and ahead of the low along the residual boundary as it retreats north as a weak warm front over the Keys and south FL through the afternoon. Increasing low-level saturation within the warm frontal zone overlaid with glancing ascent from the passage of the upper-level trough may sustain convection into the overnight hours. Although deep-layer flow and surface-based buoyancy will be adequate for 30-40 knots of effective bulk shear, weakness in the lapse rate profile near 600-650 mb will likely modulate updraft intensities. Instances of small hail and strong wind gusts are possible, but the overall severe threat remains too low for probabilities. ..Moore/Grams.. 12/17/2022 Read more

No watches are valid as of Fri Dec 16 17:50:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Dec 16 17:50:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1042 AM CST Fri Dec 16 2022 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Synopsis and Discussion... An upper low will move slowly eastward over the Great Lakes and southern Ontario/Quebec on Saturday. Broad cyclonic mid-level flow will encompass much of the eastern CONUS. At the surface, appreciable low-level moisture will attempt to return northward across parts of the southern/central FL Peninsula through the period. Isolated thunderstorms may occur across this region, mainly Saturday afternoon. Mid/upper-level flow appears sufficiently strong to support updraft organization. But, poor lapse rates, weak instability, and meager forcing for ascent aloft should limit overall thunderstorm coverage and intensity. ..Gleason.. 12/16/2022 Read more