Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CST Tue Dec 20 2022 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Wednesday. ...Synopsis and Discussion... A weak mid-level disturbance will move from FL and coastal GA/SC into the western Atlantic Wednesday morning. Rich low-level moisture will remain confined along/south of a surface front that will be draped across the central/southern FL Peninsula. While isolated thunderstorms may occur across this region through the day, the lack of appreciable large-scale ascent aloft should limit overall convective coverage. A prominent upper trough is forecast to amplify further Wednesday across a broad part of the central CONUS as it translates eastward. A leading shortwave trough embedded within the larger upper trough should move quickly across the southern/central Plains to the Southeast and OH Valley through the period. Surface ridging centered over the East Coast will be slow to erode through Wednesday night. This should inhibit the return of appreciable low-level moisture inland across coastal SC. But, enough elevated instability may coincide with increasing forcing for ascent to support occasional thunderstorms late Wednesday night over parts of SC. ..Gleason.. 12/20/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Tue Dec 20 2022 Valid 201630Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FL KEYS VICINITY... ...SUMMARY... While severe storms are unlikely, a severe wind gust is possible across the Florida Keys vicinity this evening. ...FL Keys... Scattered showers and isolated thunderstorms along a weak baroclinic/convergence zone over the western FL Straits, south and west of the Keys, should spread east-northeast into this evening towards the coastal waters adjacent to the southern tip of the peninsula. Farther west, an MCS across the east-central Gulf should persist east-southeast along the baroclinic zone, but weaken as it moves east of the Loop Current. The 12Z KEY sounding sampled weak, near-moist-adiabatic lapse rates that are not expected to steepen during the period, which will limit updraft strength. In addition, low-level winds should remain modest, yielding only minor enhancement to the low-level hodograph. The bulk of deep-layer shear contribution will be from strengthening winds above 700 mb. Overall setup suggests convection this evening will most likely remain sub-severe and weaken with approach to land over the Keys and adjacent portion of the southern Everglades. ..Grams/Moore.. 12/20/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0944 AM CST Tue Dec 20 2022 Valid 201700Z - 211200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track. ..Squitieri.. 12/20/2022 .PREV DISCUSSION... /ISSUED 0154 AM CST Tue Dec 20 2022/ ...Synopsis... A continental polar airmass characterized by cold surface temperatures will encompass much of the western and central CONUS. As a result, fire-weather concerns will generally be minimal on Tuesday, despite locally dry/breezy conditions over parts of the central and southern High Plains. ...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 0134 PM CST Mon Dec 19 2022 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will continue to spread from eastern Texas across the Gulf Coast states. Though small hail is possible, severe weather remains unlikely over land. Surface observations along the Gulf Coast continue to show a rather stable air mass for surface-based parcels, with the best instability well offshore into the northwest Gulf of Mexico. Though a tight instability gradient will exist near the surface low, it is unlikely that this better air mass will reach shore. To the north, modest elevated instability and moderate deep-layer effective shear may support a few embedded storms capable of small hail through tonight, but hail over 1.00" diameter appears unlikely across Texas and Louisiana. ..Jewell.. 12/19/2022 .PREV DISCUSSION... /ISSUED 1015 AM CST Mon Dec 19 2022/ ...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. Read more

No watches are valid as of Mon Dec 19 19:39:02 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Dec 19 19:39:02 UTC 2022.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1252 PM CST Mon Dec 19 2022 Valid 201200Z - 211200Z ...NO CRITICAL AREAS... Fire weather concerns remain minimal for Tuesday. Localized dry and windy conditions are possible in the immediate lee of the Rockies from northern NM through CO and into southern WY. However, the potential for elevated or critical wind/RH over receptive fuels remains low. ..Moore.. 12/19/2022 .PREV DISCUSSION... /ISSUED 0109 AM CST Mon Dec 19 2022/ ...Synopsis... Fire-weather concerns will be minimal on Tuesday, as cold surface temperatures accompanying a continental polar airmass infiltrate much of the western and central CONUS. ...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 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