SPC Tornado Watch 548

2 years 10 months ago
WW 548 TORNADO NC SC VA CW 301640Z - 010200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 548 NWS Storm Prediction Center Norman OK 1240 PM EDT Fri Sep 30 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Eastern North Carolina Northeast South Carolina Southeast Virginia Coastal Waters * Effective this Friday afternoon and evening from 1240 PM until 1000 PM EDT. * Primary threats include... A few tornadoes possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms capable of producing a few tornadoes will continue to develop and move rapidly northwest around the circulation of Hurricane Ian. The tornado potential will gradually shift north across the watch area through this afternoon and this evening. The tornado watch area is approximately along and 75 statute miles either side of a line from 40 miles east northeast of Norfolk VA to 60 miles southwest of Wilmington NC. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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. && AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 0 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 14045. ...Bunting Read more

SPC Sep 30, 2022 1630 UTC Day 1 Convective Outlook

2 years 10 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1113 AM CDT Fri Sep 30 2022 Valid 301630Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER EXTREME NORTHEAST SOUTH CAROLINA...EASTERN NORTH CAROLINA AND SOUTHEAST VIRGINIA... ...SUMMARY... A few tornadoes will be possible today across the coastal Carolinas and southeast Virginia, in association with Hurricane Ian. A few strong gusts may also occur across portions of Utah into Colorado Friday afternoon. ...NC/VA... Hurricane Ian will move inland this afternoon across the SC coast and continue moving north tonight. An associated warm front, currently extending northeast from the center along the southern NC coast, is forecast to lift northward in tandem with the center this afternoon. Richer boundary-layer moisture, characterized by dew points in the 70s, is expected to lift northward across eastern NC this afternoon and eventually into southeast VA by evening. Some potential for pockets of greater heating will exist as drier air is entrained into the circulation, contributing to areas of greater surfaced based instability across eastern NC. Strong low/mid-level flow around the circulation will contribute to low-level shear supportive of supercell structures with the risk for a few tornadoes, as supported by most 12z CAM solutions. Transient supercell characteristics have already been observed near and south of the southern NC coast this morning within the more favorable thermodynamic environment. ...UT/CO... Despite some morning cloud cover, surface heating will occur in advance of a cold front, resulting in modest buoyancy by afternoon. Moderately strong westerly mid-level flow (30-35 kts) will result in an environment favorable for some degree of updraft organization. Thunderstorms are expected to increase in coverage this afternoon in association with a southeast-moving upper low as modest large scale ascent develops over the area. Isolated strong/damaging gusts should be the primary severe hazard with the strongest storms through early evening. ..Bunting/Moore.. 09/30/2022 Read more

SPC MD 1845

2 years 10 months ago
MD 1845 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF WESTERN MT...FAR EASTERN ID...AND NORTHWEST WY
Mesoscale Discussion 1845 NWS Storm Prediction Center Norman OK 0106 PM CDT Thu Sep 29 2022 Areas affected...Parts of western MT...far eastern ID...and northwest WY Concerning...Severe potential...Watch unlikely Valid 291806Z - 292030Z Probability of Watch Issuance...5 percent SUMMARY...The risk of isolated strong to severe gusts and marginal hail should gradually increase in the next few hours. Overall, the severe risk is expected to remain marginal and localized. DISCUSSION...Latest water vapor imagery shows a closed midlevel low tracking slowly eastward across the Northwest, preceded by increasing DCVA/large-scale ascent characterized by modest midlevel height-falls over the last 12 hours. As the increasing ascent continues overspreading a weak north/south-oriented baroclinic zone from western MT into eastern ID, convection will gradually increase in coverage given continued destabilization/steepening low/midlevel lapse rates this afternoon. Regional VWP data depicts 30-40-kt south-southwesterly midlevel flow preceding the closed midlevel low, which should favor modestly elongated/straight midlevel hodographs (35-45 kt of effective shear) across western MT southward into eastern ID and northwest WY. While buoyancy will be somewhat marginal (generally driven by steep low/midlevel lapse rates), the combination of strengthening forcing for ascent and sufficient deep-layer shear could favor loosely organized convection as it spreads northeastward this afternoon. Marginal hail will be possible with any initial cellular development, though strong to severe gusts should be the main hazard as convection grows upscale into clusters or bands owing to the strengthening large-scale ascent amid straight hodographs. Overall, the severe threat is expected to remain marginal and localized. ..Weinman/Thompson.. 09/29/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...RIW...TFX...PIH...MSO... LAT...LON 44021131 44781154 45391201 46061243 46961311 47541367 48081387 48461357 48671302 48661173 48261105 47421037 46700996 45770971 44940953 43670964 43450998 43391080 43511120 44021131 Read more

SPC Sep 29, 2022 1730 UTC Day 2 Convective Outlook

2 years 10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1236 PM CDT Thu Sep 29 2022 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN NORTH CAROLINA/SOUTHEASTERN VIRGINIA VICINITY... ...SUMMARY... A few tornadoes will be possible Friday into Friday night across the coastal Carolinas and southeast Virginia, in association with Tropical Cyclone Ian. A few strong gusts may also occur across the southern and eastern Utah/western Colorado vicinity Friday afternoon. ...Synopsis... An upper low over the northern Rockies is forecast to drift slowly southward Friday, while expansion/evolution of an eastern U.S. low occurs as Ian begins to acquire hybrid/extratropical characteristics later in the period. At the surface, Hurricane Ian is forecast to be located off the southeastern U.S. coast early Friday, and is forecast by the National Hurricane Center to make landfall over coastal South Carolina during the afternoon. Ian's circulation is expected to become increasingly baroclinic with time, as it curves north-northwestward toward/into western North Carolina through the end of the period. ...Northeastern South Carolina and eastern North Carolina into southeastern Virginia... As Ian shifts inland/north-northwestward Friday, moist/tropical air being advected westward/northwestward into eastern portions of the Carolinas and Virginia will maintain modest CAPE within a pseudo "warm-sector." With favorably strong low-level shear east of the storm/south of a baroclinic/warm-frontal type boundary moving northwestward across Virginia, potential for rotating convective cells within bands east of Ian's center is apparent. As such, potential for a few tornadoes remains evident, warranting a bump upward to 5% tornado probability/SLGT risk from extreme northeastern South Carolina northward into southwestern Virginia. The risk will gradually shift northward with time, in tandem with Ian's progression, with the southeastern Virginia risk likely to continue into/through the overnight hours. ...Southern and eastern Utah into western Colorado... As the upper low drifts slowly southward, modestly enhanced west-southwesterly flow will be maintained across the Utah/Colorado area on the southeastern fringe of the cyclone. With cool air aloft, associated with the low, providing steep mid-level lapse rates, diurnal heating will contribute to modest (around 500 J/kg) mixed-layer CAPE to evolve through the afternoon. This will support initiation of scattered to isolated, low-topped storms, which may become locally sustained/organized given modestly supportive shear that is expected. This, combined with a rather deep/dry mixed layer may support locally gusty winds with stronger storms, and some potential for a gust or two to reach severe levels. ..Goss.. 09/29/2022 Read more

SPC Sep 29, 2022 1630 UTC Day 1 Convective Outlook

2 years 10 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1119 AM CDT Thu Sep 29 2022 Valid 291630Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FROM NORTHERN UT INTO WESTERN MT... ...SUMMARY... A few strong to severe thunderstorms are possible from northern Utah and western Wyoming into western Montana this afternoon and evening. ...Northern UT into MT this afternoon/evening... A midlevel low will move slowly east-southeastward over the northern Rockies, as midlevel height rises occur upstream over the northeast Pacific. Ascent preceding the midlevel low/trough, and an associated low-midlevel baroclinic zone, will provide an environment to support thunderstorms this afternoon/evening from northern UT into MT. Regional 12z soundings revealed modest low-midlevel moisture and the potential for steep low-level lapse rates and weak surface-based buoyancy with surface heating/mixing. Thus, high-based thunderstorm development is expected this afternoon, with the potential for isolated strong outflow gusts based on inverted-v profiles and some downward momentum transfer. Isolated, marginally severe hail may occur in MT, closer to the midlevel cold core. ...Southeast Atlantic Coast through early Friday... The core of Tropical Storm Ian, which has some hybrid/baroclinic characteristics, is moving off the east central FL coast and is forecast to strengthen some while gradually turning more northward toward the Carolinas on Friday (see latest NHC forecasts for details). A cool/dry, continental air mass is entrenched across the Carolinas now, with widespread rainfall offshore. It will take until Friday during the day to bring richer moisture and surface-based buoyancy inland across northeast SC and coastal NC, so any severe/tornado threat should remain offshore until the day-2 forecast period. ..Thompson/Weinman.. 09/29/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 10 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1011 AM CDT Thu Sep 29 2022 Valid 291700Z - 301200Z The forecast remains on track with only minor adjustments needed based on morning surface observations and the latest hi-res guidance. Localized elevated conditions will be possible this afternoon across northeast NV as well as the OK/TX Panhandles and portions of the central Plains. However, confidence in the duration/coverage of these conditions remains too limited for additional highlights. ..Moore.. 09/29/2022 .PREV DISCUSSION... /ISSUED 0134 AM CDT Thu Sep 29 2022/ ...Synopsis... Surface pressure gradients between Hurricane Ian and the surface high near the Great Lakes will continue on Thursday, allowing lingering areas of elevated fire weather to be possible across the far western Florida Panhandle into southern Alabama. ...Alabama/Florida Panhandle... Areas of elevated fire weather are possible across the far western Florida Panhandle into southern Alabama on Thursday where minimum humidity around 30 percent will coincide with northeasterly winds sustained at 15-20 mph. Fuels along the Florida Panhandle into Alabama continue to be critically dry above the 95 percentile. Further east along the Florida Panhandle, low clouds may increase in the afternoon as moisture moves in from the east due to Hurricane Ian's continued track off the East Coast. This may keep afternoon relative humidity above elevated thresholds with lighter surface winds amid more shallow mixing. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC MD 1842

2 years 10 months ago
MD 1842 CONCERNING TORNADO WATCH 546... FOR PARTS OF CENTRAL AND EAST-CENTRAL FL
Mesoscale Discussion 1842 NWS Storm Prediction Center Norman OK 1218 PM CDT Wed Sep 28 2022 Areas affected...Parts of central and east-central FL Concerning...Tornado Watch 546... Valid 281718Z - 281915Z The severe weather threat for Tornado Watch 546 continues. SUMMARY...The risk of a few tornadoes should gradually increase across parts of central and east-central FL this afternoon, with a potential focus from Lake Okeechobee northward to near Orlando FL during the next few hours. DISCUSSION...Latest surface observations indicate upper 70s/lower 80s surface temperatures from Lake Okeechobee northeastward toward Melbourne FL, where at least modest cloud thinning has developed. These warmer surface temperatures, coupled with upper 70s boundary-layer dewpoints gradually spreading northward should allow for surface-based convective inflow. The MLB VWP depicts modest low-level hodograph curvature owing to backed surface winds beneath strengthening south-southwesterly flow. Farther west, the VWP hodograph from TBW is much larger (500-600 m2/s2 0-1 km SRH), though buoyancy is much weaker with westward extent. From Lake Okeechobee northward to around Orlando FL, a favorable overlap of the surface-based buoyancy and large looping low-level hodographs should prove favorable for increasing tornado potential during the next few hours. This is especially the case as a broken band of low-topped supercells spread northward across this locally favorable environment (two TDSs recently observed with this activity over Okeechobee and St. Lucie Counties). ..Weinman.. 09/28/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...TBW... LAT...LON 27248117 27438141 27798167 28168177 28428161 28478133 28438105 28328083 28178072 27818049 27318034 27118048 27118089 27248117 Read more

SPC Sep 28, 2022 1730 UTC Day 2 Convective Outlook

2 years 10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Wed Sep 28 2022 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF NORTHEASTERN FLORIDA... ...SUMMARY... A couple of tornadoes will be possible across parts of east-central and northeast Florida Thursday morning and afternoon, in association with Tropical Cyclone Ian. ...Synopsis... An upper trough is forecast to progress across the Canadian Maritime Provinces and northeastern U.S. Thursday, before moving into the North Atlantic during the second half of the period. Meanwhile, a second trough/low is forecast to make slow eastward progress across the northwestern quarter of the CONUS. In between, ridging will prevail, though several short-wave cyclonic disturbances will progress through weak/largely westerly flow across the Plains/Canadian Prairies. At the surface, a cold front will move across the northwestern U.S. and into the Great Basin/Intermountain region, while a lee trough is maintained over the High Plains. In the East, high pressure will prevail, with the exception of the Southeast where Ian -- likely to have weakened to tropical storm status -- will be moving across central and northeastern Florida through the day, and then offshore overnight. ...Parts of central and northeastern Florida... Current forecasts from the National Hurricane Center place the center of Ian over central Florida at the start of period, with slow northeastward motion across northeastern portions of Florida through the day before moving offshore north of Melbourne by early evening. Given this location and movement, inland tornado risk will be confined largely to northeast Florida coastal counties, with the remainder of the risk offshore. As such, a small SLGT risk/5% tornado area is being maintained at this time, for areas near and north of Cape Canaveral. Risk will diminish after dark, as Ian continues to shift offshore. ..Goss.. 09/28/2022 Read more

SPC Sep 28, 2022 1630 UTC Day 1 Convective Outlook

2 years 10 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 28 2022 Valid 281630Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON/EVENING ACROSS EAST CENTRAL FL... ...SUMMARY... Tornadoes are expected this afternoon/evening, especially across east central Florida, in association with Major Hurricane Ian. ...East central FL this afternoon/evening... Major Hurricane Ian is approaching the FL Gulf coast near Fort Myers and Port Charlotte, and the storm core will continue to move northeastward across central FL through tonight (see latest NHC advisories for additional information). Visible satellite imagery reveals a zone of filtered surface heating along the Atlantic coast, to the east of the thicker clouds with the hurricane core along the Gulf coast, as discussion in MD 1841. Also, low-level flow has veered and hodographs have become less favorable for supercells across the Keys, while the stronger low-level shear/hodograph curvature will persist through the afternoon/evening across east central FL. As new convection forms in the zone of stronger surface heating, tornadoes will be possible as supercells move northward into the weak baroclinic zone across central/east central FL, with a diminished threat farther northwest and deeper into the rain-cooled air. This baroclinic zone may shift slowly northward along the Atlantic coast though early tonight, in advance of the hurricane core. ..Thompson/Weinman.. 09/28/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 10 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1118 AM CDT Wed Sep 28 2022 Valid 281700Z - 291200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL GULF COAST... An Elevated risk area is introduced to portions of central/eastern WY where guidance has come into better agreement in the potential for sustained elevated wind/RH conditions this afternoon. RH values are already falling into the low 30s, and should fall to near 10-15% by this afternoon as winds increase to 15 mph. ...Gulf Coast... Morning surface observations are sampling near-record low dewpoint values along the Gulf Coast and into AL. Winds have increased in response to the approach of Hurricane Ian to the southeast, with gusts up to 30 mph already being reported. Critical conditions remain likely for much of the Gulf Coast and will be most prevalent for south-central AL into the western FL Panhandle. ...Southeast Oregon into Northwest Nevada... The KMAX and KRGX VWPs have shown an increase in low to mid-level winds over the past 2-3 hours as the upper wave moves ashore. Such winds will overspread the northern Sierra/southern Cascades by late afternoon, in line with the latest guidance. Elevated to locally critical conditions remain likely. ...Southern to Northern Plains... Dry conditions and receptive fuels remain prevalent across much of the Plains with RH reductions into the 20-30% expected by late afternoon for most locations. While winds will generally remain below 15 mph, a few locations may see periods of elevated fire weather conditions where winds can exceed 15 mph. This potential appears most likely across southern to central OK and through the southern Red River Valley of the north along the ND/MN border, though confidence in a more robust threat remains too limited for additional highlights. ..Moore.. 09/28/2022 .PREV DISCUSSION... /ISSUED 1215 AM CDT Wed Sep 28 2022/ ...Synopsis... The broad upper-level ridge will continue to shift eastward into the Plains, today. In the Northwest, an upper-level trough will move into Washington and Oregon. At the surface, a stout surface high will move into the upper Midwest. A cold front will be draped across the northern Gulf into north Florida. Hurricane Ian will continue into central Florida. ...Central Gulf Coast... The combination of the strong surface high to the north and the strong pressure gradient around Hurricane Ian will drive moderately strong northerly winds across much of the Southeast. With these areas remaining dry, fuels are receptive to fire spread. RH below 30% should occur over much of the region, particularly areas that are not impacted by high level outflow clouds from Ian. There is a corridor along/near the Gulf Coast that could see RH as low as 20%. This area is most likely to see critical fire weather as sustained winds near 15-20 mph with higher gusts probable. ...Southeast Oregon into northwest Nevada... The approach of the upper-level trough will promote a surface trough in the Columbia basin and drive moderate downslope winds of 15-20 mph. RH of 15-20% is expected. Critical conditions are possible, but will be localized and brief. ...Central/northern Plains... As a lee trough develops in the Canadian Rockies, southerly winds may increase to 15-25 mph in parts of the Dakotas into Nebraska. Fuels have become marginally drier after recent rains. However, fire weather concerns are expected to be mitigated by cooler temperatures and upper-level cloud cover. The overlap of low RH and the stronger winds is not expected to be widespread. Locally elevated to near critical conditions are possible in central Wyoming. However, fuels are generally marginal and duration of these conditions will be short-lived. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Tornado Watch 546

2 years 10 months ago
WW 546 TORNADO FL CW 280855Z - 282100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 546 NWS Storm Prediction Center Norman OK 455 AM EDT Wed Sep 28 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Central and South Florida Coastal Waters * Effective this Wednesday morning and afternoon from 455 AM until 500 PM EDT. * Primary threats include... Several tornadoes likely SUMMARY...As Hurricane Ian continues to approach the west coast of Florida, a strong eastern-peripheral wind field and a very moist air mass will support the potential for supercells and a related tornado risk. This tornado potential will initially be focused across the southern Peninsula early today, but is likely to further increase and spread northward into the central Florida Peninsula by late morning and afternoon. The tornado watch area is approximately along and 70 statute miles east and west of a line from 45 miles southwest of Miami FL to 15 miles east northeast of Orlando FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). 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 545... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 0 inches. Extreme turbulence and surface wind gusts to 50 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 15030. ...Guyer Read more

SPC Sep 27, 2022 1730 UTC Day 2 Convective Outlook

2 years 10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Sep 27 2022 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE FLORIDA PENINSULA... ...SUMMARY... A few tornadoes will be possible across the Florida Peninsula on Wednesday, in association with Hurricane Ian. ...Synopsis... A highly amplified upper trough will continue moving slowly eastward across eastern NOAM Wednesday, while a second trough -- initially over the northeastern Pacific -- shifts inland across southern British Columbia and the Pacific Northwest during the second half of the period. In between, ridging will prevail across the U.S. Great Plains and Canadian Prairies. At the surface, a cold front is forecast to move slowly across the Pacific Northwest, while high pressure prevails over the central and much of the eastern portions of the country. The main exception will be over the Southeast, where a quasistationary front will become more ill-defined, as Hurricane Ian shifts out of the eastern Gulf and into Florida through the end of the period. ...Florida Peninsula... While track uncertainties with respect to Ian (see the latest forecasts from the National Hurricane Center) persist, risk for a few tornadoes remains evident as the storm approaches -- and eventually moves into -- the Florida Peninsula. As low-level flow intensifies with time, shear in the eastern half of the circulation will support rotating updrafts within banded convection. As such, brief tornadoes will be possible for an extended period of time. At this time, with the storm track continuing to trend more eastward, future adjustments to northern fringes of the risk area will likely be required. ..Goss.. 09/27/2022 Read more

SPC Sep 27, 2022 1630 UTC Day 1 Convective Outlook

2 years 10 months ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 27 2022 Valid 271630Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT ACROSS THE KEYS AND SOUTH FL INTO PARTS OF CENTRAL FL... ...SUMMARY... Tornadoes are possible across the Florida Keys and south Florida today, and may spread into parts of central Florida overnight with Hurricane Ian. ...South FL and the Keys through tonight... Major Hurricane Ian will move northward or north-northeastward through tonight across the extreme southeast Gulf of Mexico, as rain bands east-through-northeast of the center continue to overspread south FL and the Keys. Some expansion of the stronger wind field, and resultant stronger vertical shear (effective SRH of 200-400 m2/s2), will occur through tonight as Ian continues to deepen (see latest NHC advisories for additional information). Widespread rain across south FL has held surface temperatures in the mid 70s through the morning with minimal surface-based buoyancy. However, some cloud breaks and modest surface heating is underway across the Keys, and should develop slowly inland from the southeast FL coast through the afternoon. Likewise, slightly higher boundary-layer dewpoints (>76 F) will spread inland, with sufficient destabilization to support supercells moving inland. Thus, the threat for tornadoes is expected to gradually increase from south-to-north later this afternoon/evening, and persist into the overnight hours. Please see SPC MD 1833 for additional details. ..Thompson/Weinman.. 09/27/2022 Read more

SPC Day 1 Fire Weather Outlook

2 years 10 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1048 AM CDT Tue Sep 27 2022 Valid 271700Z - 281200Z The forecast remains on track with only minor adjustments needed for both the Gulf Coast and southern Oregon regions. Morning water vapor imagery shows broad subsidence across the Southeast, which will maintain warm, dry conditions today as RH values continue to fall into the 20-30% range. Sustained winds near 15 mph are expected by early afternoon, and gusts up to 20-25 mph will support periods of critical fire weather conditions. Across northern CA/southern OR, GOES Derived Winds is estimating mid-level winds near 20-25 mph, which is in line with latest guidance and supports the ongoing forecast (see previous discussion below). ...Southwest to Central Oklahoma... A few surface stations are reporting elevated fire weather conditions across western OK ahead of a weak surface trough/cold front. Boundary layer winds are expected to weaken through the day across the region, which will limit the overall fire weather potential despite receptive fuels. However, periods of patchy elevated conditions are possible during the 16-21 UTC period roughly across the Altus, OK to Watonga, OK region. ..Moore.. 09/27/2022 .PREV DISCUSSION... /ISSUED 0126 AM CDT Tue Sep 27 2022/ ...Synopsis... An amplified pattern aloft featuring a broad trough in the east, a large ridge over the central U.S., and a shortwave trough over the Northwest will be in place today. At the surface, a trough will develop in the lee of the Cascades while a surface high will build into the upper Midwest. The approach of Hurricane Ian along the western Florida coast will strengthen the surface pressure gradient for the central Gulf Coast states. ...South-central Oregon... Afternoon winds will reach 15-20 mph as the surface trough deepens in the Columbia Basin. Some increase in high cloud cover is possible and may impact RH reductions in parts of the region. However, at least some areas of 15-20% appear possible during the afternoon. ...Central Gulf Coast Vicinity... The region will be situated in a dry, post-frontal airmass. The combinations of a building surface high to the north and the approach of Ian to the southeast should promote a modest increase in surface winds. In general, winds around 15 mph are expected with locally higher sustained speeds and gusts. Dry fuels and RH that will likely fall to near 25% or lower will support an increase in fire weather concerns during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Tornado Watch 544

2 years 10 months ago
WW 544 TORNADO FL CW 271255Z - 272100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 544 NWS Storm Prediction Center Norman OK 855 AM EDT Tue Sep 27 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of South Florida Coastal Waters * Effective this Tuesday morning and afternoon from 855 AM until 500 PM EDT. * Primary threats include... A few tornadoes possible SUMMARY...Hurricane Ian will continue to move north-northeastward and likely further intensify as per the National Hurricane Center. A very moist airmass and strengthening low-level shear will support an increasing tornado potential from the Florida Keys across the southern Peninsula through the afternoon. The tornado watch area is approximately along and 80 statute miles north and south of a line from 70 miles west northwest of Key West FL to 20 miles east southeast of Miami FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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. && AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 0 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 14020. ...Guyer Read more

SPC Sep 26, 2022 1730 UTC Day 2 Convective Outlook

2 years 10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Mon Sep 26 2022 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS WEST-CENTRAL AND SOUTHWESTERN FLORIDA... ...SUMMARY... A few tornadoes will be possible across parts of Florida Tuesday into Tuesday night, in association with Hurricane Ian. ...Synopsis... Large-scale upper troughing will continue over eastern NOAM Tuesday, while a second low/trough over the northeastern Pacific gradually approaches the Pacific Northwest. In between, expansive ridging will extend from Texas and the Desert Southwest northward across the Rockies and into the Canadian Prairie Provinces. At the surface, a cold front will remain roughly in place from the southeastern U.S. Atlantic Coast, west-southwestward along the Gulf Coast vicinity. To the south, Hurricane Ian is progged to be shifting slowly northward into/across the eastern Gulf of Mexico through the period. Please refer to the latest forecasts regarding Ian from the National Hurricane Center. ...Florida Peninsula... As Ian moves slowly northward, the low-level flow across the Florida Peninsula south of the aforementioned cold front -- particularly across west-central and southwestern Florida -- will increase with time. Widespread convection surrounding Ian will overspread the area from south to north, with embedded cellular convection within bands surrounding the center of circulation. As the inland wind field gradually strengthens, potential for rotating cells will likewise increase, along with associated tornado potential. This risk may increase through the afternoon, and continue into the overnight hours as the storm gradually shifts northward. ..Goss.. 09/26/2022 Read more
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