Severe Storms

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

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1018 AM CST Fri Dec 16 2022 Valid 161700Z - 171200Z ...NO CRITICAL AREAS... Elevated wind/RH conditions will be possible today across terrain-favored areas of southern CA, and also across parts of the south-central High Plains, but marginal fuel conditions and cool temperatures are still expected to temper the fire-weather threat. See the previous discussion below for more details. ..Dean.. 12/16/2022 .PREV DISCUSSION... /ISSUED 0142 AM CST Fri Dec 16 2022/ ...Synopsis... A deep low-pressure system will move slowly eastward across the Upper Midwest/Great Lakes vicinity. On the backside of this system, enhanced north-northwesterly flow aloft and large-scale subsidence will persist over the western CONUS. As a result, surface high pressure will remain centered over the Great Basin, yielding continued dry/breezy offshore flow across southern CA. While locally elevated conditions are possible here (especially over parts of Ventura and Los Angeles Counties), these conditions appear too localized for Elevated highlights -- especially given marginally receptive fuels. Over the central/southern High Plains (particularly over southwest KS and the TX/OK Panhandles), breezy/gusty northwesterly winds and 15-25 percent RH are expected during the afternoon. However, cold boundary-layer conditions and marginal fuels should generally temper the fire-weather threat. ...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 Fri Dec 16 2022 Valid 161630Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast today and tonight. ...Synopsis... Morning surface observations and satellite imagery show a robust surface low to the south/southeast of Long Island with a cold front draped southwestward over far south FL and into the Gulf of Mexico. Thunderstorm activity will be focused in the vicinity of this low and the cold front for today/tonight. Latest forecast soundings from along the New England coast suggest weak buoyancy may linger within the warm conveyor belt ahead of the low through mid-afternoon. With convective cloud top cooling noted in recent IR imagery ahead of the wave, a few sporadic lightning flashes seem plausible through 21 UTC. Across south FL, isolated to scattered showers/thunderstorms will continue to develop through the afternoon and evening amid modest buoyancy, weak inhibition, and adequate lift along the cold front. Marginal deep-layer flow may yield transient storm organization, but the combined buoyancy and wind profiles suggest a limited severe threat. ..Moore/Grams.. 12/16/2022 Read more

WW 0591 Status Updates
STATUS REPORT ON WW 591 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SW SRQ TO 25 SSW ORL TO 25 NE ORL TO 45 ESE DAB. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 2048 ..DEAN..12/15/22 ATTN...WFO...MLB...TBW...JAX... STATUS REPORT FOR WT 591 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS FLC009-015-027-049-055-081-095-097-105-115-117-152040- FL . FLORIDA COUNTIES INCLUDED ARE BREVARD CHARLOTTE DESOTO HARDEE HIGHLANDS MANATEE ORANGE OSCEOLA POLK SARASOTA SEMINOLE AMZ552-152040- CW . ADJACENT COASTAL WATERS INCLUDED ARE VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20 NM THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 591 TORNADO FL CW 151300Z - 152100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 591 NWS Storm Prediction Center Norman OK 800 AM EST Thu Dec 15 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Central and north-central Florida Coastal Waters * Effective this Thursday morning and afternoon from 800 AM until 400 PM EST. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 70 mph possible SUMMARY...A threat for damaging winds and a tornado or two should increase through the remainder of the morning and linger through at least midafternoon, with a band of thunderstorms moving eastward from the Gulf across the watch area. Isolated supercells ahead of the main convective band also may pose a tornado hazard, especially over western areas. The tornado watch area is approximately along and 80 statute miles either side of a line from 15 miles west northwest of Saint Petersburg FL to 30 miles north northeast of Melbourne FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 590... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25030. ...Edwards Read more

MD 2048 CONCERNING TORNADO WATCH 591... FOR CENTRAL FL PENINSULA
Mesoscale Discussion 2048 NWS Storm Prediction Center Norman OK 1212 PM CST Thu Dec 15 2022 Areas affected...Central FL Peninsula Concerning...Tornado Watch 591... Valid 151812Z - 151945Z The severe weather threat for Tornado Watch 591 continues. SUMMARY...The threat for locally damaging wind and a brief tornado or two will continue this afternoon. DISCUSSION...Convection has organized into a loosely organized QLCS early this afternoon from near Tampa Bay northeastward across the central FL Peninsula. A few wind gusts in the 40-50 mph range have been noted over the last 1-2 hours, as well as occasional weak low-level rotation embedded within the line, and a possible brief tornado earlier in Pinellas County. Wind profiles (as noted in KTBW and KMLB VWPs and the 16Z Cape Canaveral sounding) remain favorable for organized storms, though some veering flow near the surface has weakened low-level shear/SRH to some extent. Low/midlevel lapse remain rather weak across the central FL Peninsula, which may continue to limit the severe threat somewhat, though modest heating/destabilization downstream of the line will help maintain a risk for strong/damaging gusts and a brief tornado or two through mid afternoon, especially across the west-central FL Peninsula. While the primary cold front is lagging the ongoing convection, substantial redevelopment behind the QLCS appears unlikely, with the stronger large-scale ascent lifting away from the region as the main deep-layer cyclone occludes over the Upper Midwest. ..Dean.. 12/15/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MLB...TBW... LAT...LON 28258042 27728121 27278197 26978264 27268279 27588269 28828147 28928092 28748053 28258042 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1102 AM CST Thu Dec 15 2022 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 12/15/2022 .PREV DISCUSSION... /ISSUED 0154 AM CST Thu Dec 15 2022/ ...Synopsis... Surface high pressure is forecast to intensify Friday as an arctic front continues east and south toward the MS Valley. Overnight temperatures below freezing and calm winds are expected across much of the western US and Plains States, with the exception of the West Coast. Offshore flow and occasional dry surface conditions will be possible into the weekend. However, with limited potential for dry/windy conditions to overlap with receptive fuels, fire-weather concerns are low through the forecast period. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2047 CONCERNING HEAVY SNOW FOR NORTHWEST MINNESOTA...EASTERN NORTH DAKOTA...AND FAR NORTHEAST SOUTH DAKOTA.
Mesoscale Discussion 2047 NWS Storm Prediction Center Norman OK 1046 AM CST Thu Dec 15 2022 Areas affected...Northwest Minnesota...eastern North Dakota...and far northeast South Dakota. Concerning...Heavy snow Valid 151646Z - 152045Z SUMMARY...Moderate snow will advance westward through mid-afternoon. DISCUSSION...Moderate to locally heavy snow is currently being observed near the North Dakota/Minnesota border and vicinity. This area of enhanced snowfall is associated with a westward moving upper-level trough which has now wrapped around the parent upper-level low. Moderate to locally heavy snow will continue to advance westward through mid-afternoon before starting to weaken as the shortwave trough slows and eventually stalls as it gets absorbed by the upper low. In addition to the moderate to heavy snow, some visibility reductions can be expected amid surface winds of 25 to 30 mph and gusts to 40 mph within the tight pressure gradient on the west side of the surface low. Despite weakening snowfall rates this afternoon/evening, blowing snow and associated visibility restrictions are expected to persist through the overnight period as the surface low moves slowly northeast and the pressure gradient remains across the region. ..Bentley.. 12/15/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...FGF...ABR...BIS... LAT...LON 48779556 48459501 47849478 46919509 46169523 45129575 44629655 44759711 44959748 45379798 46529868 47749886 48519845 48789776 48779556 Read more