Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Mon Oct 17 2022 Valid 181200Z - 191200Z No changes. See previous discussion below. ..Bentley.. 10/17/2022 .PREV DISCUSSION... /ISSUED 0206 AM CDT Mon Oct 17 2022/ ...Synopsis... Elevated fire weather conditions are probable across portions of the central Gulf Coast Tuesday afternoon as a dry, post-frontal air mass moves into the region. Unseasonably dry air, currently observed across the northern Plains, will continue to push south over the next 48 hours. Afternoon RH values in the 20-30% range will be common from the northern Plains to the central Gulf Coast region for Tuesday afternoon. Recent hi-res ensemble guidance shows reasonably high probability for 20% RH across south-central LA into the FL Panhandle with winds near 15-20 mph. Stronger gusts up to 25 mph will be possible amid a strong cold advection regime in the wake of the prior frontal passage. The latest fuel analyses hint that ERC values are generally near or above the 90th percentile outside of the few pockets of rainfall that have fallen over the past 72 hours, which will support the fire weather threat. More localized fire weather concerns may emerge across east-central TX and into parts of OK/KS where 15 mph winds may overlap with reduced RH. However, these conditions appear too localized and/or will likely occur over areas with recent rainfall, precluding the need for additional highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Mon Oct 17 18:03:01 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Oct 17 18:03:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Mon Oct 17 2022 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather is unlikely across the U.S. on Tuesday. ...Synopsis... A deep cyclone will remain over parts of Ontario and Quebec on Tuesday, with strong cyclonic flow aloft encompassing the eastern half of the CONUS. Meanwhile, weak upper ridging will remain over the West. At the surface, high pressure will continue spreading south across the Plains, Gulf of Mexico, and Southeast, maintaining dry offshore flow. One area that may experience a few afternoon storms is south FL, where a moist and unstable air mass will remain ahead of a cold front. Temperatures aloft will not be particularly cold for this time of year, with 500 mb values of -7 to -8 C resulting in poor lapse rates. Heating will aid storm formation, though convergence will be weak with the westerly flow regime. Isolated cells appear most likely along the eastern coast of FL, though severe appears unlikely. Elsewhere, weak elevated instability may result in sporadic embedded lightning flashes across parts of New England, with very low instability values precluding a severe risk despite strong shear. ..Jewell.. 10/17/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1157 AM CDT Mon Oct 17 2022 Valid 171700Z - 181200Z Expanded the Elevated delineation into southeast Missouri based on morning forecast guidance. Otherwise, the forecast appears on track and no additional changes were necessary. ..Bentley.. 10/17/2022 .PREV DISCUSSION... /ISSUED 0115 AM CDT Mon Oct 17 2022/ ...Synopsis... Fire weather concerns will emerge primarily across parts of the Plains and Midwest today amid breezy conditions within a dry post-frontal air mass. Dry conditions will persist across much of the Great Basin and parts of the Pacific Northwest, but a building ridge will limit wind speeds and modulate the overall fire weather concern outside of locations that see stronger, terrain-induced winds. ...Lower MO River Valley... Early-morning surface observations are sampling dewpoints in the mid to upper teens across much of the eastern Plains. These values are near the 10th percentile climatologically for mid October, and when combined with diurnal warming, should result in RH reductions well into the low 20s this afternoon. Winds today should be somewhat more benign compared to previous days as high pressure builds over the northern Plains, but sustained winds near 15-20 mph (gusting to 25 mph) should support a broad swath of elevated fire weather conditions through the lower MO River Valley and possibly into portions of the Midwest. Colder temperatures to the northeast and recent rainfall to the south of the risk area will limit the extent of the fire 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 1116 AM CDT Mon Oct 17 2022 Valid 171630Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING NEAR MID ATLANTIC AND CENTRAL/SOUTHEASTERN FLORIDA COASTAL AREAS AND PERHAPS NEAR THE LOWER RIO GRANDE VALLEY... ...SUMMARY... Widely scattered strong thunderstorms are possible later today into this evening across parts of the Atlantic Seaboard, mainly near Mid Atlantic and central through southern Florida coastal areas. ...Synopsis... To the east of a prominent blocking high centered over the northern U.S. Intermountain Region, models indicate that large-scale mid-level troughing, already encompassing much of the nation east of the Rockies, will be reinforced by another strong jet digging from the Upper Midwest through the lower Ohio Valley by late tonight. A significant embedded cyclone may deepen further while occluding across the lower Great Lakes/southeastern Ontario vicinity, with an associated reinforcing cold intrusion likely surging across much of the Atlantic and Gulf coasts by daybreak Tuesday. A preceding front is already advancing into/through the lower Rio Grande Valley, but has stalled near or offshore of southeastern New England coastal areas into southeastern Virginia and the North Carolina Piedmont. Seasonably moist air has largely become confined to Deep South Texas and Texas coastal areas, where it is increasingly becoming undercut by the lead surface cold front. In the wake of mid-level troughing already well offshore of the southern Atlantic coast, low-level moisture ahead of the stalled lead front may be increasing, but remains relatively modest. ...Mid Atlantic... Models suggest that strengthening frontogenesis along the cold front advancing east of the Appalachians by late this afternoon may provide support for the initiation of scattered thunderstorms. However, with stronger 850 mb flow already in the process of shifting offshore, and forecast to maintain an appreciable southwesterly component inland of coastal areas, potential for substantive further moistening and boundary-layer destabilization appears low. The most appreciable destabilization (including CAPE up to around 500 J/kg) appears likely to remain confined to parts of northeastern North Carolina into southeastern Virginia. This may be sufficient to support a couple of strong storms by early this evening, as the trailing cold front overtakes the stalled lead front. Aided by strongly sheared, 30-50 kt mean ambient flow, these could pose at least some risk for small hail and potentially damaging wind gusts before weakening/spreading offshore later this evening. Farther north, into northern Mid Atlantic coastal areas, convective potential seems likely to remain even more limited due to weaker instability, but scattered low-topped showers and thunderstorms may still be accompanied by gusty winds. ...Florida.... Low-levels are moistening and destabilizing beneath 30-40+ kt west-northwesterly mid-level flow (around 500 mb), and it does appear that the environment will continue to become conditionally supportive of organized convective development this afternoon. However, low-level convergence across the interior peninsula may remain weak, as light southwesterly low-level flow (around 850 mb) gradually veers to an increasing westerly component. This probably will focus increasing forcing for ascent near central and southeastern coastal areas late this afternoon and evening, but isolated strong storms posing a risk for severe wind and hail may be possible before convection spreads offshore this evening. ...Lower Rio Grande Valley... Forcing to support vigorous thunderstorm development probably will become largely focused along the higher terrain to the southwest of the river this afternoon into tonight. ..Kerr/Squitieri.. 10/17/2022 Read more

No watches are valid as of Sun Oct 16 17:56:01 UTC 2022.

No Mesoscale Discussions are in effect as of Sun Oct 16 17:56:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1217 PM CDT Sun Oct 16 2022 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ALONG PARTS OF THE EAST COAST AND OVER DEEP SOUTH TEXAS... ...SUMMARY... A few marginally severe storms are possible Monday afternoon from the eastern Carolinas into northeast Florida, and over Deep South Texas. Locally damaging gusts or hail may occur. ..East Coast... A deep/stacked low will be centered near Lake Huron through the period, with strong cyclonic flow aloft affecting much of the eastern CONUS. At the surface, a cold front will move across the Mid Atlantic during the day, trailing southwestward across the eastern Carolinas, central GA, and toward the central Gulf Coast and further west into southern TX. Heating ahead of the front along with sufficient moisture will lead to MLCAPE near 1000 J/kg over the eastern Carolinas, with values closer to 1500 J/kg into FL where dewpoints will remain in the mid to upper 60s F. Strengthening flow aloft will lead to long hodographs (effective shear of 50 kt), favoring cellular activity. However, winds below 700 mb will remain relatively weak, and this may temper both the hail and wind threat. Cells are expected to form around 21Z over the Carolinas, and a bit earlier over northern FL, producing sporadic severe gusts or hail. ...South Texas... Heating will occur over Deep South Texas ahead of an east-west oriented cold front which will push rapidly south throughout the day. This front will undercut a moist air mass characterized by 70s F dewpoints, with MLCAPE over 2000 J/kg. Given weak winds below 700 mb as well as front-parallel flow aloft, cluster of storms may tend to propagate east/southeastward near the front, producing sporadic strong gusts. The threat may begin relatively early in the day, and spread east/southeast toward the Gulf Coast by 00Z. ..Jewell.. 10/16/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Sun Oct 16 2022 Valid 161700Z - 171200Z ...NO CRITICAL AREAS... Gusty north/northwesterly winds have developed across the northern and central Plains amid deep mixing. Cool temperatures should keep relative humidity high enough to avoid any fire weather concerns. No changes were made. See the previous discussion below. ..Bentley.. 10/16/2022 .PREV DISCUSSION... /ISSUED 0115 AM CDT Sun Oct 16 2022/ ...Synopsis... The potential for widespread fire weather concerns will remain limited for today. A dry, but cool, continental air mass will continue to overspread the central Plains and portions of the Midwest behind a southward moving cold front. Although sustained north/northwesterly winds near 15-20 mph are expected from the Dakotas into the portions of NE/IA, cooler temperatures will limit diurnal RH reductions. A few locations may see RH values fall into the upper 20s, which may allow for brief periods of elevated fire weather conditions. Across the Pacific Northwest, a 4-5 mb offshore pressure gradient remains in place across the Cascades, but is expected to weaken over the next 24 hours. The downslope flow regime may support pockets of elevated to critical fire weather conditions within the higher terrain, but this threat remains too spatially limited to warrant highlights. ...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 1125 AM CDT Sun Oct 16 2022 Valid 161630Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE RIO GRANDE VALLEY AND ALSO THE CENTRAL APPALACHIANS... ...SUMMARY... Isolated severe thunderstorms are possible from southeast New Mexico across far west to southwest Texas, beginning in the mid-afternoon and continuing through tonight. Locally damaging winds are also possible across parts of the southern Appalachians, mainly in the late afternoon to early evening. ...Southeast NM to South TX... Thunderstorm coverage is expected to increase as favorable large-scale ascent associated with a shortwave trough moves slowly east in advance of the upper low near the southern AZ/Sonora border. Meanwhile, a surface cold front will continue moving southward into the Upper Rio Grande Valley and should limit surface-based destabilization north of the Trans-Pecos today. Where sufficient insolation can occur ahead of the front, a corridor of modest buoyancy with MLCAPE of 1000-1500 J/kg is expected to develop. Despite weak low-level flow ahead of the front, increasing flow above 700 mb will result in long/straight hodographs and potential for a few supercells with mid-level rotation near/north of the surface front. Isolated large hail should be the primary threat as convection is largely undercut from north to south. A severe storm or two may linger into tonight across south-central TX with any supercells over the higher terrain of northern Coahuila that can spread east across the Rio Grande. ..Central/southern Appalachians... Filtered heating and a slow/modest increase in boundary-layer moisture should result in some destabilization this afternoon, with MLCAPE of a few hundred J/kg expected. An east-west ribbon of enhanced low-level warm/moist advection may be sufficient to support showers with embedded thunderstorms later this afternoon. Weak downdrafts could help mix down 30-40 kt 850-mb westerlies and result in a few stronger gusts. ..Bunting/Squitieri.. 10/16/2022 Read more

No watches are valid as of Sat Oct 15 17:47:02 UTC 2022.

No Mesoscale Discussions are in effect as of Sat Oct 15 17:47:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Sat Oct 15 2022 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHERN NEW MEXICO INTO SOUTHWEST TEXAS... ...SUMMARY... Several thunderstorms, accompanied by an isolated severe hail/wind risk, are expected across southern New Mexico into southwest Texas Sunday afternoon and evening. ...Synopsis... A longwave mid-level trough will amplify along the East Coast as surface lee troughing intensifies across the Hudson Valley and an associated surface cold front sags southward across the Carolina Piedmont into southwest Texas tomorrow/Sunday. Meanwhile, an upper low across the Desert Southwest will become an open wave as it decays and ejects into the southern High Plains. Surface low development is expected along the international border, resulting in the northwestward advection of an appreciable low-level moisture plume into southwestern Texas. Ahead of the southward sagging cold front and southern High Plains upper low, adequate lift and buoyancy will promote scattered to widespread thunderstorm development from late morning into the evening hours. Flow aloft may become strong enough across portions of southern New Mexico into southwestern Texas to support at least an isolated severe threat. ...Southern New Mexico into Southwest Texas... Widespread clouds and occasional showers will be overspreading the southern High Plains as a weakening MCS sags southward across central Texas at the start of the period. A damaging gust or two cannot be ruled out with the MCS past 12Z Sunday before dissipating, but the severe threat is expected to be very sparse at best. The northwestward advection of mid 60s F surface dewpoints beneath 6-7 C/km mid-level lapse rates should foster 500-1000 J/kg of tall-skinny MLCAPE in the absence of more robust surface heating across southern New Mexico into southwest Texas. 10-20 kt southerly low-level flow quickly veering to southwesterly at 40-50 kts in the 600-500 mb layer will promote modestly curved but very elongated hodographs given 500-300 mb winds approaching 70 kts. As such, any storms that can develop, mature, and root into the boundary layer may become supercells with a threat of isolated large hail, though a severe gust or two is also possible. Timing for severe storm development should be mid afternoon across southern New Mexico into Far West Texas, with additional supercell development possible along the Rio Grande later in the evening. ...Central Appalachians... Despite meager moisture return, strong flow aloft will be prevalent ahead of the surface cold front, which is poised to traverse eastern Tennessee to southern Virginia region during the late afternoon hours. Shear may be strong enough to support mainly small hail with some of the longer-lasting thunderstorms and an instance of marginally severe hail cannot be ruled out. Nonetheless, the severe threat should be sparse at best, with no severe probabilities introduced this outlook. ..Squitieri.. 10/15/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1113 AM CDT Sat Oct 15 2022 Valid 151630Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS PORTIONS OF OKLAHOMA AND ARKANSAS... ...SUMMARY... Scattered large hail and damaging wind gusts are possible across portions of Arkansas and Oklahoma, mainly this evening. Isolated severe wind and hail are also possible from interior southern California into Arizona, mainly this afternoon. ...OK/AR... No substantial changes have been made to the ongoing outlook. Morning surface analysis shows a weak boundary extending from western OK into central AR. South of the boundary, southerly low-level winds are slowly transporting moisture northward, with dewpoints in the mid 60s now entering southern OK. By late afternoon, a combination of strong daytime heating, increasing moisture, and strengthening low-level winds/convergence will lead to scattered thunderstorm development. Forecast soundings show steep low and mid-level lapse rates with 500mb temperatures ranging from -13 to -15C. Moderate CAPE values will support a risk of large hail in the stronger updrafts through the mid evening. A few clusters of storms could congeal into bowing structures after dark, with a risk of locally damaging wind gusts. ...AZ/Southeast CA... An upper low over northern Baja CA will result in cool temperatures aloft and ample moisture across parts of AZ and southeast CA today, leading to rather widespread thunderstorms. A few of the stronger cells could produce hail and gusty winds this afternoon, but the overall severe threat is expected to remain marginal. ..Hart/Dean.. 10/15/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1057 AM CDT Sat Oct 15 2022 Valid 151700Z - 161200Z No changes to the ongoing forecast. ..Wendt.. 10/15/2022 .PREV DISCUSSION... /ISSUED 0113 AM CDT Sat Oct 15 2022/ ...Synopsis... Fire weather concerns will remain limited outside of the Pacific Northwest. Upper-level ridging over the northeast Pacific will maintain dry conditions for the northwestern CONUS, while a cool, but dry, air mass continues to overspread the central Plains. Winds are generally expected to remain weak within the driest air masses across the Great Basin, Southeast, and parts of the southern Plains. ...Central Cascades... Early-morning surface pressure observations show a 2-4 mb offshore pressure gradient in place across the central Cascades. This is expected to foster strengthening easterly winds through the day as diurnal mixing increases. Sustained winds near 15 mph may gust to 20-30 mph at times. The downslope flow regime will yield RH reductions into the 20-30% range, which should support a few hours of elevated fire weather conditions this afternoon over an area with reasonably dry fuels (ERC values generally in the 80-95th percentile). ...Central to northern Plains... Breezy north/northwesterly winds are expected from NE through the Dakotas as a surface high builds in the lee of the Canadian and northern Rockies. Despite 15-25 mph sustained winds, a combination of cooler continental air and widespread low-level clouds should limit diurnal RH reductions for most areas. However, locations that see broken clouds may experience periods of elevated fire weather conditions with RH values falling into the 20s. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Fri Oct 14 17:35:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Oct 14 17:35:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 PM CDT Fri Oct 14 2022 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO SOUTHERN OKLAHOMA...CENTRAL ARKANSAS AND FAR SOUTHWEST TENNESSEE/NORTHWEST MISSISSIPPI... ...SUMMARY... Afternoon and evening thunderstorms are expected to evolve from Oklahoma to the Tennessee Valley area. Isolated large hail and strong gusts will accompany these thunderstorms. Additional strong storms may produce sporadic hail and gusty winds across portions of southeast California central and southern Arizona. ...Southern Plains to southwest TN/northwest MS... The upper trough centered over Ontario and the Midwest will persist on Saturday, while shortwave ridging builds over the southern High Plains to the central Rockies. Southerly low-level flow beneath the upper ridge and to the south of a nearly-stationary surface front will support 60s F surface dewpoints across OK/TX into AR and vicinity. Cool midlevel temperatures will result in steep midlevel lapse rates, while heating ahead of the front aids in moderate destabilization. Vertically veering wind profiles with effective shear magnitudes around 25-35 kt will aid in organized thunderstorms capable of severe hail and strong gusts. Convection will increase in coverage as the cold front across the TX Panhandle and northern OK/AR begins to shift south during the late afternoon and evening hours with some severe potential continuing toward the Red River through the evening hours. ...Southeast CA into central/southern AZ... An upper low off the northern Baja Coast will move east to southwest AZ on Saturday, bringing a band of enhanced midlevel flow over the region. Surface dewpoints in the mid 50s to low 60s will be in place across the region, while daytime heating combined with modestly steep midlevel lapse rates support MLCAPE values around 750-1250 J/kg. Effective shear values around 25 kt will support at least transient updraft organization. Forecast hodographs appear favorable for midlevel rotation and hail production. Steep low-level lapse rates also may aid in strong gusts. A few of the strongest storms may produce severe hail and gusts through the evening hours. ..Leitman.. 10/14/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Fri Oct 14 2022 Valid 141700Z - 151200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF SOUTHEAST WYOMING INTO NORTHEAST COLORADO...SOUTHWEST NEBRASKA...AND CENTRAL KANSAS... Some areal expansions were made to the eastern extent of the Elevated delineation, with no changes made to the rest of the fire weather highlights. This decision is supported by current surface observations, showing 25-40 percent RH values and spotty 15-20 mph winds in place from the central High Plains to points east of the MS River. Clear skies across the central and eastern CONUS will promote boundary-layer mixing through the afternoon as a 60+ kt 500 mb jet max rotates around the Great Lakes upper low and overspreads the Plains and OH/TN Valleys by afternoon peak heating, as suggested by 16Z mesoanalysis. As such, RH should lower into the 15-25 percent range over the central/eastern U.S., with widespread 15+ mph sustained westerly surface winds expected. 20+ mph sustained west-northwesterly surface winds are also possible across the Plains as the strongest mid-level winds pass over the region, necessitating the maintenance of Critical highlights per latest guidance consensus. ..Squitieri.. 10/14/2022 .PREV DISCUSSION... /ISSUED 0105 AM CDT Fri Oct 14 2022/ ...Synopsis... Critical fire weather conditions are expected this afternoon across the central Plains with widespread Elevated conditions extending well into the Ohio River Valley. Early-morning surface observations show a diffuse cold front across the northern Plains/upper MS River Valley that will push southward into the central Plains and Midwest through the day. Increasing gradient winds ahead/along the front coupled with antecedent dry conditions will support widespread fire weather concerns. ...Central Plains... Despite overnight temperatures falling into the 30s across the Plains, a dry air mass (featuring dewpoint temperatures near the 10th percentile for mid-October) remains in place and is limiting overnight RH recovery. A persistent northwesterly flow regime along and ahead of the front will foster diurnal RH reductions well into the 15-25% range from southeast WY/northeast CO into central KS and northern OK this afternoon. Sustained winds near 15-25 mph appear likely with frequent gusts to 30-35 mph probable. Fuels across much of the region remain dry, but the fire weather threat may be greatest across central KS where drought conditions are most severe per recent drought/fuel analyses. ...Ohio River Valley... Warm and windy conditions are expected through the lower OH River Valley as a warm front lifts north through the day and establishes a modest low-level thermal ridge from southeast MO into IN. The combination of dry air advection from the southern Plains and diurnal warming/mixing will yield RH values into the 20-30% range by late afternoon with southwest winds near 15-20 mph (gusting to 30-35 mph at times). Fuels across this region are less receptive compared to the Plains after some rainfall in recent days; however, the Elevated risk area denotes where dry/breezy conditions will overlap with drier fuels within a substantial 14-day rainfall deficit. Localized critical conditions are possible, especially across the KY/IL/IN tri-state region, but should remain too spatially and temporally limited for additional highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more