Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Sep 29 2023 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE UPPER MIDWEST... ...SUMMARY... Isolated large hail and locally damaging winds will be possible across parts of the Upper Midwest between about 6 PM to 2 AM CDT. ...20Z Update... ...Far Northeast NE to East-Central MN... Overall scenario outlined in the previous discussion remains. Isolated surface-based thunderstorm development is still possible along the cold front pushing southeastward across eastern SD and NE. However, greater thunderstorms potential exists later this evening and overnight as a strengthening low-level jet fosters isentropic ascent along the frontal zone. Weak deep-layer shear should limit updraft intensity and duration, but isolated instance of hail are possible within the first few hours of development. ..Mosier.. 09/29/2023 .PREV DISCUSSION... /ISSUED 1117 AM CDT Fri Sep 29 2023/ ...Northeast NE to east-central MN... Primary categorical change with this outlook is to reorient the spatial extent of the expected threat in the wake of this morning's storms amid above-average consistency in 12Z CAM guidance. Gradual mid-level height rises are expected across the region as a shortwave trough progresses northeast from the Upper Red River Valley across northern ON. Differential boundary-layer heating will reinforce the southwest to northeast baroclinic zone from northeast NE/southeast SD through east-central MN. A storm or two might develop along the southwest flank of this corridor in the early evening where MLCIN is minimized with a conditional threat of marginal severe wind gusts. The more probable scenario is for slightly elevated thunderstorm development to occur after sunset from southwest to east-central MN on the nose of a strengthening low-level jet. Low-level hodographs will favor updraft rotation with initial storms, but a decrease in winds with height along with some reduction in steep lapse rates owing to slow mid-level warming should temper hail magnitudes beyond golf ball size. The longevity of the isolated large hail threat should also be curtailed to around 3-4 hours as storm mode becomes dominated by clusters and instability/buoyancy wanes overnight. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0217 PM CDT Fri Sep 29 2023 Valid 301200Z - 011200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WESTERN CO EASTERN UT AND SOUTHERN WY... No changes to the ongoing forecast. ..Wendt.. 09/29/2023 .PREV DISCUSSION... /ISSUED 0202 AM CDT Fri Sep 29 2023/ ...Synopsis... The deepening trough over the western CONUS is forecast to continue to strengthen as it overspreads strong mid-level flow across the Great Basin and western Rockies. Enhanced surface winds are likely from NM to WY, along with dry and warm surface conditions. Several hours of elevated to critical fire-weather concerns are likely. ...Western Slope... The upper trough over the western US is forecast to deepen significantly D2/Sat with strong south/southwesterly flow likely over the Rockies. A deepening surface low over the Great Basin, and the increase in mid-level winds will bolster surface winds to 25-30 mph through the afternoon across portions of western CO and southern WY. Along with a moderately strong wind field, dry downslope flow and warm surface temperatures will support afternoon RH values of 12-20%. The best overlap of critical humidity and surface winds appears to be across parts of western CO coincident with the most receptive fuels. Thus, several hours of critical fire-weather conditions are likely D2/Sat afternoon and evening. Though not as strong, gusty surface winds and low humidity are also likely over parts of the Four Corners into western NM. Deep mixing and warm surface temperatures will favor afternoon RH values below 20% within relatively dry fuels. Widespread elevated to locally critical conditions appear possible over parts of NM and AZ. ...High Plains... To the east across the central High Plains, gusty southerly winds of 15-20 mph and afternoon humidity below 25% are possible D2/Sat. While forecast confidence is relatively low given various model differences, a few hours of dry and breezy conditions may support locally elevated fire concerns across parts of eastern CO and far western KS where fuels remain relatively dry. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Thu Sep 28 23:16:02 UTC 2023.

No Mesoscale Discussions are in effect as of Thu Sep 28 23:16:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0455 PM CDT Thu Sep 28 2023 Valid 301200Z - 061200Z ...Days 3-4/Saturday-Sunday... A highly amplified large-scale trough will move slowly eastward over the western CONUS on Days 3-4/Saturday-Sunday. Preceding this feature, a belt of strong deep-layer south-southwesterly flow will overspread a dry air mass from parts of the Southwest into the eastern Great Basin and central Rockies. Ample boundary-layer mixing into the strong deep-layer flow, coupled with a tightening surface pressure gradient, will yield an expansive area of 20-25+ mph sustained south-southwesterly surface winds (with higher gusts) amid 10-15 percent RH over the aforementioned areas on Day 3/Saturday. Strong surface winds will persist across the same areas on Day 4/Sunday (with a slight eastward shift in the strongest winds), though substantial RH reductions will generally be confined to portions of the Southwest. Widespread elevated to locally critical conditions are expected for both days, with the primary limiting factor being marginally receptive fuels where the best overlap of strong winds and low RH is expected. Father east, persistent lee troughing will favor breezy southerly surface winds over portions of the central and southern Plains each day. Along the western edge of the richer boundary-layer moisture return, a slim overlap of the strong winds and low RH is possible over portions of the central and southern High Plains. However, the potential for critical conditions appears too low for probabilities at this time. ...Days 5-8/Monday-Thursday... The large-scale trough and related enhanced flow aloft will move gradually eastward across the central CONUS. Similar to Day 4/Sunday, breezy/gusty southerly surface winds (albeit slightly weaker) are expected over the central/southern Plains on Day 5/Monday, with similar uncertainties regarding RH reductions. Thereafter, a cold front and related precipitation should overspread the Great Plains, generally reducing the fire-weather risk across the CONUS. ..Weinman.. 09/28/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Thu Sep 28 2023 Valid 291200Z - 301200Z ...Central and Southern Plains... An Elevated area was added from parts of west-central KS south-southwestward into portions of northeast NM. From KS into northwest OK, 20-25 mph sustained southerly surface winds (with gusts upwards of 35 mph) will primarily support a wind-driven fire risk given marginal RH reductions (25-30 percent) along the western edge of the more-substantial boundary-layer moisture return. Given the strong/gusty winds, lower to middle 90s temperatures, and somewhat marginal RH/fuels, Elevated highlights are warranted. From portions of the OK/TX Panhandles into northeast NM, the combination of 10-15 percent RH and 15-20 mph west-southwesterly surface winds will also favor locally elevated fire-weather conditions. Elsewhere, only minor changes were made based on the latest high-resolution guidance. For details, see the previous discussion below. ..Weinman.. 09/28/2023 .PREV DISCUSSION... /ISSUED 0119 AM CDT Thu Sep 28 2023/ ...Synopsis... Elevated fire weather conditions are expected across parts of southern WY into adjacent areas of UT and CO Friday afternoon. Early-morning water-vapor imagery across the northeast Pacific depicts two shortwave impulses embedded within the mean northwesterly flow. The second of these is expected to amplify over the next 48 hours along the West Coast, resulting in strengthening mid-level southwesterly flow from the lower CO River Valley into the central Rockies. This flow regime will also maintain dry conditions across the Great Basin. Consequently, dry and windy conditions are forecast across a large swath of the Great Basin Friday afternoon. Recent ensemble guidance suggests elevated to locally critical fire weather conditions are probable, but may be patchy in nature across the region. This, combined with generally unreceptive fuels for most locations, limits confidence in the coverage of the fire weather threat. However, portions of southern WY, northeast UT, and northwest CO should see favorable overlap of elevated conditions with dry fuels - especially after several previous days of similarly dry/windy weather. Elsewhere, windy conditions are expected across KS and southern NE as a lee trough continues to strengthen. While 20+ mph winds are expected, confidence in sub-25% RH is limited due to persistent moisture advection from the south. Trends will continue to be monitored for fuel dryness and the quality of moisture return. ...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 0235 PM CDT Thu Sep 28 2023 Valid 282000Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are unlikely today or tonight. ...20Z Update... Overall forecast reasoning remains unchanged, and the only change made to the previous outlook was expanding general thunder northwestward across Far West TX. A strong storm or two remains possible across western KY/TN this afternoon and evening, but generally weak shear and warm temperatures aloft should keep the overall severe potential low. Small hail also remain possible late tonight/early Friday from eastern SD into southwest MN. Marginal environmental conditions should keep the potential for severe hail low. ..Mosier.. 09/28/2023 .PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Sep 28 2023/ ...Kentucky/Tennessee... A relatively small cluster of thunderstorms continues to persist southeastward along the western Kentucky/Tennessee border vicinity late this morning. These storms, and the frontal zone just to the north, regionally reside on the southwest periphery of an upper low centered near Lower Michigan, within a cyclonically curved belt of moderately strong mid-level westerlies. The midday-ongoing storms do not appear likely to produce severe weather, although some strong storms could redevelop later this afternoon in the same general vicinity across western portions of Tennessee/Kentucky. This will be as the synoptic front stalls or moves slightly southward, with outflows/differential heating on the western edge of persistent early day convection also factors. While a narrow zone of moderate instability will exist in this corridor later today, mid-level height rises are expected and effective shear should generally remain 30 kt or less. While a locally severe storm or two cannot be conclusively ruled out late this afternoon/early evening, the potential for organized/sustained storms is currently expected to remain low. ...Eastern SD/far southeast ND and southwest/south-central MN... Late tonight, low-level warm advection is expected to increase across the region, largely in response to an approaching shortwave trough. As a low-level jet strengthens into the region, elevated convection is expected to develop after midnight. Forecast soundings late tonight/early Friday suggest that some potentially strong elevated updrafts are plausible. Small hail could occur, but the potential for 1-inch (or greater) hailstones should remain low. Read more

No watches are valid as of Wed Sep 27 23:45:02 UTC 2023.

MD 2202 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHERN ILLINOIS AND SOUTHERN INDIANA INTO KENTUCKY
Mesoscale Discussion 2202 NWS Storm Prediction Center Norman OK 0643 PM CDT Wed Sep 27 2023 Areas affected...Southern Illinois and southern Indiana into Kentucky Concerning...Severe potential...Watch possible Valid 272343Z - 280145Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorms developing across southern Illinois are expected to intensify as they migrate east into the Ohio River Valley. Large hail and severe wind gusts will be possible with the more intense cells, but thunderstorm coverage and mode remains uncertain. Trends will be monitored for watch issuance. DISCUSSION...Over the past hour, a few transient attempts at convective initiation have been noted across southern IL ahead of a subtle mid-level impulse and in the vicinity of a decaying surface low. Additional attempts at CI are expected over the coming hours as isentropic ascent increases over a warm front draped from southern IL into the OH River Valley. Temperatures across the warm sector - which is bound to the east by a residual outflow boundary - have begun falling with the onset of nocturnal cooling. MLCAPE values have been falling due to this cooling, but MUCAPE values should remain near 1000 J/kg as saturation of the surface-850 mb layer increases. Additionally, weak south/southeasterly flow across the region with 30-35 knot flow aloft is supporting somewhat elongated hodographs with effective bulk shear values near 30-35 knots. Some veering in the lowest 1 km is noted in regional VWPs, which is supporting effective SRH values around 100-150 J/kg. This environment is favorable for organized convection, including the potential for a few supercells. However, several modulating factors are noted. Deep-layer shear and storm motion vectors are forecast to be largely oriented along the warm front, which should favor a tendency for upscale growth. These factors may be offset by the isolated nature of storms given the relatively weak ascent over the region, so storm mode remains somewhat uncertain. Additionally, the noted nocturnal cooling may hinder the potential for surface-based convection, limiting the tornado potential and favor large hail and severe winds as the primary hazards. Trends will continue to be monitored for the needed for a watch issuance, which may be conditional on storm coverage and organization. ..Moore/Hart.. 09/27/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LMK...IND...PAH...ILX...LSX... LAT...LON 38548523 38288487 37848482 37288516 36898588 36758649 37068764 37328846 37548904 37848943 38288944 38688888 38758804 38768588 38548523 Read more

No Mesoscale Discussions are in effect as of Wed Sep 27 22:34:01 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0428 PM CDT Wed Sep 27 2023 Valid 291200Z - 051200Z Fire concerns will remain low through the extended period. The upper-level pattern will remain fairly persistent through much of the period, with troughing across the western US and ridging across the central/eastern US. The increased pressure gradient and flow aloft between these two features will keep winds breezy across the Southwest into Great Basin and across the Central Plains. Cooler temperatures, fuels near seasonal averages, and potential for precipitation will help temper fire spread potential across much of the Southwest and Great Basin. Little to no rainfall is forecast across portions of southern Arizona and western New Mexico. Periods of Elevated fire weather may be possible. Fuels within this region are near seasonal normal but multiple days of windy/dry conditions will likely lead to drying fuels. This trend will be monitored with potential for highlights in the coming days. Across the Central Plains, westerly flow across the Rockies will support strengthening lee troughing and periods of increased south to southwesterly flow across the central high plains. Relative humidity is forecast to remain above Critical thresholds, though spotty Elevated to near Critical conditions will be possible on D3 - Friday and D4 - Saturday across western Kansas/eastern Colorado. Late in the period by D8 - Wednesday, the western trough may eject eastward into the Plains. Model spread in where the surface low will develop leads to low confidence in where any windy/dry conditions will overlap. ..Thornton.. 09/27/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0428 PM CDT Wed Sep 27 2023 Valid 291200Z - 051200Z Fire concerns will remain low through the extended period. The upper-level pattern will remain fairly persistent through much of the period, with troughing across the western US and ridging across the central/eastern US. The increased pressure gradient and flow aloft between these two features will keep winds breezy across the Southwest into Great Basin and across the Central Plains. Cooler temperatures, fuels near seasonal averages, and potential for precipitation will help temper fire spread potential across much of the Southwest and Great Basin. Little to no rainfall is forecast across portions of southern Arizona and western New Mexico. Periods of Elevated fire weather may be possible. Fuels within this region are near seasonal normal but multiple days of windy/dry conditions will likely lead to drying fuels. This trend will be monitored with potential for highlights in the coming days. Across the Central Plains, westerly flow across the Rockies will support strengthening lee troughing and periods of increased south to southwesterly flow across the central high plains. Relative humidity is forecast to remain above Critical thresholds, though spotty Elevated to near Critical conditions will be possible on D3 - Friday and D4 - Saturday across western Kansas/eastern Colorado. Late in the period by D8 - Wednesday, the western trough may eject eastward into the Plains. Model spread in where the surface low will develop leads to low confidence in where any windy/dry conditions will overlap. ..Thornton.. 09/27/2023 ...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 0249 PM CDT Wed Sep 27 2023 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER OH VALLEY... ...SUMMARY... Scattered strong to severe thunderstorms may impact parts of the lower Ohio Valley this afternoon into tonight, and pose some risk for severe weather. ...20Z Update... ...Lower Ohio Valley... Modest destabilization is still anticipated in the wake of early showers and thunderstorms (and associated cloud cover) ahead of a weakly convergence frontal zone. Thunderstorms are still expected along this frontal zone later this evening. Cold mid-level temperatures will foster moderate buoyancy amid generally weak to moderate vertical shear. A predominantly multicellular mode is anticipated, but a supercell or two is possible as well. ..Mosier.. 09/27/2023 .PREV DISCUSSION... /ISSUED 1141 AM CDT Wed Sep 27 2023/ ...Lower Ohio Valley... An upper low over the Midwest (temperatures still around -16C at 500 mb) will drift eastward over northern portions of Illinois/Indiana and southern Lake Michigan through tonight, with moderately strong cyclonically curved westerlies influencing the lower Ohio Valley into Tennessee Valley. Moderate destabilization, with MLCAPE to around 1000-1500 J/kg, is expected this afternoon near/south of the synoptic front and weak surface low, particularly to the west of decaying thunderstorm clusters and cloud cover that persist late this morning near/south of the Ohio River. Renewed thunderstorm development/intensification may occur across east-central Kentucky Bluegrass into the Cumberland Plateau vicinity by mid-afternoon. A couple of stronger cells may be accompanied by small to marginally severe hail and localized damaging wind gusts, before the storms spread into a more stable environment toward the mountains. Farther west/northwest is where somewhat more substantive boundary-layer destabilization is expected across southern portions of Illinois/Indiana into west-central Kentucky, with storms expected to increase by late afternoon and early evening. A few transient supercells could occur, but multicellular clusters capable of hail/wind are otherwise probable, potentially including some semi-organized clusters this evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Sep 27 2023 Valid 272000Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER OH VALLEY... ...SUMMARY... Scattered strong to severe thunderstorms may impact parts of the lower Ohio Valley this afternoon into tonight, and pose some risk for severe weather. ...20Z Update... ...Lower Ohio Valley... Modest destabilization is still anticipated in the wake of early showers and thunderstorms (and associated cloud cover) ahead of a weakly convergence frontal zone. Thunderstorms are still expected along this frontal zone later this evening. Cold mid-level temperatures will foster moderate buoyancy amid generally weak to moderate vertical shear. A predominantly multicellular mode is anticipated, but a supercell or two is possible as well. ..Mosier.. 09/27/2023 .PREV DISCUSSION... /ISSUED 1141 AM CDT Wed Sep 27 2023/ ...Lower Ohio Valley... An upper low over the Midwest (temperatures still around -16C at 500 mb) will drift eastward over northern portions of Illinois/Indiana and southern Lake Michigan through tonight, with moderately strong cyclonically curved westerlies influencing the lower Ohio Valley into Tennessee Valley. Moderate destabilization, with MLCAPE to around 1000-1500 J/kg, is expected this afternoon near/south of the synoptic front and weak surface low, particularly to the west of decaying thunderstorm clusters and cloud cover that persist late this morning near/south of the Ohio River. Renewed thunderstorm development/intensification may occur across east-central Kentucky Bluegrass into the Cumberland Plateau vicinity by mid-afternoon. A couple of stronger cells may be accompanied by small to marginally severe hail and localized damaging wind gusts, before the storms spread into a more stable environment toward the mountains. Farther west/northwest is where somewhat more substantive boundary-layer destabilization is expected across southern portions of Illinois/Indiana into west-central Kentucky, with storms expected to increase by late afternoon and early evening. A few transient supercells could occur, but multicellular clusters capable of hail/wind are otherwise probable, potentially including some semi-organized clusters this evening. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Sep 27 2023 Valid 281200Z - 291200Z An Elevated delineation was added across western Kansas/eastern Colorado in anticipation of increasing southerly flow amid dry conditions. HREF probabilities indicate 70-90 percent of meeting Elevated criteria across the Kansas/Colorado border. Coordination with local partners indicates fuels within this region have experienced drying due to rainfall deficits over the last few weeks. See previous discussion for more information concerning Elevated concerns across southern WY and northwest CO. ..Thornton.. 09/27/2023 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Sep 27 2023/ ...Synopsis... Elevated fire weather conditions are expected again on Thursday across portions of southern WY and into far northwest CO. The progression of the upper wave over the Pacific Northwest will strengthen lee troughing over the northern and central High Plains over the next 48 hours. As a result, low to mid-level flow is forecast to strengthen across the eastern Great Basin and Four Corners regions. With a dry air mass expected to already be in place by Thursday afternoon, elevated fire weather conditions are expected from northern AZ into UT, western CO, and southern WY. However, fuels across most of this region are not receptive outside of southern WY and adjacent portions of northwest CO where 30-day rainfall deficits and ERC values near the 80th percentile are noted in recent analyses. ...Western Kansas... Drier, windier deterministic solutions hint at the potential for elevated conditions across western KS Thursday afternoon. Fuels over northwest KS appear to be receptive after little rainfall over the past 30 days, and may support a fire concern. However, confidence in substantial overlap of these dry fuels with sustained elevated fire weather conditions remains limited due to spread in ensemble guidance and a noted dry bias in the upstream air mass over the southern High Plains noted in some model runs. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Sep 27 2023 Valid 281200Z - 291200Z An Elevated delineation was added across western Kansas/eastern Colorado in anticipation of increasing southerly flow amid dry conditions. HREF probabilities indicate 70-90 percent of meeting Elevated criteria across the Kansas/Colorado border. Coordination with local partners indicates fuels within this region have experienced drying due to rainfall deficits over the last few weeks. See previous discussion for more information concerning Elevated concerns across southern WY and northwest CO. ..Thornton.. 09/27/2023 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Sep 27 2023/ ...Synopsis... Elevated fire weather conditions are expected again on Thursday across portions of southern WY and into far northwest CO. The progression of the upper wave over the Pacific Northwest will strengthen lee troughing over the northern and central High Plains over the next 48 hours. As a result, low to mid-level flow is forecast to strengthen across the eastern Great Basin and Four Corners regions. With a dry air mass expected to already be in place by Thursday afternoon, elevated fire weather conditions are expected from northern AZ into UT, western CO, and southern WY. However, fuels across most of this region are not receptive outside of southern WY and adjacent portions of northwest CO where 30-day rainfall deficits and ERC values near the 80th percentile are noted in recent analyses. ...Western Kansas... Drier, windier deterministic solutions hint at the potential for elevated conditions across western KS Thursday afternoon. Fuels over northwest KS appear to be receptive after little rainfall over the past 30 days, and may support a fire concern. However, confidence in substantial overlap of these dry fuels with sustained elevated fire weather conditions remains limited due to spread in ensemble guidance and a noted dry bias in the upstream air mass over the southern High Plains noted in some model runs. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Sep 26 22:23:01 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Tue Sep 26 2023 Valid 281200Z - 041200Z The large scale pattern will consist of a trough across the western US with downstream ridging across the eastern US. This will bring periods of breezy/dry conditions across the southwest as multiple waves move through the longwave trough. Cooler temperatures and precipitation will be possible across the Great Basin into the Central Rockies, limiting the overall fire threat amid fuels near seasonal normal. Areas across central/southern Arizona into New Mexico will likely remain dry but fuels within this region are also near seasonal normal. The western trough will begin to dig southward and slowly progress eastward through the weekend. The enhancement of the upper-level flow will bring potential for strengthening winds across the southwest and adjacent central high plains as a surface trough begins to develop in the lee of the Rockies. Periods of Elevated to Critical fire weather from D3 - Thursday through D6 - Sunday will be possible but confidence is low in where windy/dry conditions will overlap receptive fuels. Recent analysis indicates that the driest fuels are located across western/central Kansas into far eastern Colorado, where less recent rainfall has been observed and fine fuels will potentially support fire spread. Elsewhere, recent rainfall has left fuels at or below seasonal normal for dryness. No probabilities have been included at this time but trends will be monitored in the coming days. ..Thornton.. 09/26/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2201 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL NEW MEXICO TO FAR WEST TEXAS
Mesoscale Discussion 2201 NWS Storm Prediction Center Norman OK 0453 PM CDT Tue Sep 26 2023 Areas affected...Central New Mexico to far west Texas Concerning...Severe potential...Watch unlikely Valid 262153Z - 270000Z Probability of Watch Issuance...5 percent SUMMARY...Isolated to scattered thunderstorms developing across central New Mexico to far west Texas will pose an isolated large hail and severe wind risk through the early evening hours. Watch issuance is not expected. DISCUSSION...Thunderstorm development has been well underway across NM to far west TX, but recent GOES IR imagery and lightning trends have shown an uptick in intensity in a few cells. While not high-caliber by most measures, the environment across the region remains favorable for organized convection with 1000-1500 J/kg MLCAPE and effective shear values near 20 knots. This may support a few organized cells capable of posing a large hail risk. Dewpoint depressions across the region on the order of 40-50 F indicate that the boundary layer is fairly well mixed, and this is supported by 0-3 km lapse rates around 8-9 C/km per latest mesoanalysis estimates. This low-level thermodynamic environment, combined with PWAT values below 1 inch, is conducive for downbursts and perhaps outrunning outflows that may lead to thunderstorm clustering. Both of these scenarios would pose a risk for strong to severe gusts through the early evening hours prior to sunset and on the onset of nocturnal cooling. However, given the overall marginal convective environment, watch issuance is not expected. ..Moore/Thompson.. 09/26/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LUB...AMA...MAF...ABQ...EPZ... LAT...LON 31650663 32360702 33580722 34160688 34670603 35090471 35450313 35470262 35290194 35040178 34620188 33310240 32470262 31650310 30750362 30390394 30120432 30040469 30330507 30460516 30640531 31140613 31450647 31650663 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Tue Sep 26 2023 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MS AND UPPER OH VALLEY...NM AND WEST TX...AND NORTHERN FL... ...SUMMARY... Isolated severe thunderstorms are possible today across parts of the Midwest, across parts of New Mexico into west Texas, and possibly northern Florida. ...20Z Update... ...Mid MS Valley into the Lower OH Valley... Visible satellite imagery shows a cumulus field from IA across IL into IN, with some recent building cumulus across eastern MO as well. All of this is occurring in the vicinity of an upper low centered over eastern IA. MCD #2198 was recently issued addressing the severe potential in this area. As mentioned in that discussion, cold mid-level temperatures and steep low-level lapse rates, and resulting modest buoyancy, in the presence of low-level vorticity may result in isolated instances of hail and perhaps a brief tornado this afternoon. An associated occluded surface low is centered below this upper low, linked to another surface low over northeast IL by a weak surface trough. A cold front extends from arc second low southward into southern IL and then back westward into west-central MO. As mentioned in MCD #2200, pulse-cells and multicell storms have been increasing in coverage and intensity along this boundary. A couple instances of hail are possible with the stronger storms this afternoon. Building cumulus across far southwest MO suggests thunderstorm initiation will occur in that region as well, and marginal hail and wind probabilities were extended accordingly. ...Elsewhere... Isolated thunderstorms capable of hail and damaging gusts remain possible across NM and West TX. A strong storm or two is also possible across northern FL, as mentioned in MCD #2199. ..Mosier.. 09/26/2023 .PREV DISCUSSION... /ISSUED 1136 AM CDT Tue Sep 26 2023/ ...Midwest including Illinois/Indiana/Missouri... An upper low (-16C at 500mb) centered over eastern Iowa this morning will continue to drift east-southeastward toward and across northern Illinois through tonight. A semi-moist environment, with surface dewpoints in the upper 50s/low 60s F, will diurnally persist near/northeast of a weak surface low and occluded front/wind shift that will generally extend southeastward from the surface low. While deep-layer wind profiles will generally be weak (15-20 kt effective shear), ample CAPE with respect to low-topped storms will support the possibility of hail with the stronger pulse-type cells. Funnels appear quite plausible across areas including eastern Iowa, southern Wisconsin and northern/central Illinois, and sufficient low-level CAPE/ambient vorticity near the boundary could yield a brief tornado risk. Farther to the southwest, there is some potential that some strong to severe thunderstorms could develop near the front across central/eastern Missouri late this afternoon into tonight. MLCAPE could reach 1000-1500 J/kg MLCAPE near/south of the front, and wind profiles will be moderately strong, influenced by increasingly strong cyclonically curved westerlies in the base of the Upper Midwest shortwave trough. Thermodynamic/kinematic profiles could conditionally support some high-based supercells aside from multicellular clusters if/where storms develop. While near-frontal convergence will be modest, and the likelihood and extent of sustained deep convection may remain limited, there will be additional late night opportunities for convective development as warm advection/moisture transport increase, and some of these storms could also be strong. This region will be closely reevaluated in subsequent outlooks for a potential reintroduction of severe probabilities. ...New Mexico/West Texas... Within the weaker southern branch of westerlies, a weak shortwave trough is expected to move southeastward across the Four Corners vicinity through tonight. As it does, associated forcing for ascent should augment convective development, particularly storms initiating in response to heating across the mountains of southern/central New Mexico by early afternoon. It appears that moisture across this region will be sufficient to support initially sizable CAPE, beneath modest westerly to northwesterly flow, at least in upper levels. Stronger storms may become capable of producing marginally severe hail, then a few strong to severe gusts while propagating southeastward off the higher terrain into an unstable and more deeply mixed boundary-layer through early this evening. ...Florida Peninsula... Low severe probabilities have been introduced for the northern Florida Peninsula where storms are expected to increase/develop east-northeastward across the region, all while deep-layer shear modestly increases. High precipitable water content will support heavy precipitation loading and some potential for locally strong surface gusts. ...Coastal Oregon... Forcing for ascent within the exit region of a strong jet streak (including 70-90 kt around 500 mb) may contribute to an organized, vigorous pre-frontal convective band, associated with the surface cyclone approaching the Pacific Northwest. However, with the cyclone forecast to occlude prior to reaching the coast near/after 27/06Z, appreciable inland boundary-layer destabilization appears unlikely, and stable near-surface lapse rates may tend to mitigate the potential for downward mixing of severe surface gusts as the convective line progresses inland. Read more