Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0236 PM CDT Wed Aug 30 2023 Valid 311200Z - 011200Z No changes. See previous discussion below. ..Bentley.. 08/30/2023 .PREV DISCUSSION... /ISSUED 0154 AM CDT Wed Aug 30 2023/ ...Synopsis... As a trough across Montana lifts northward into Canada on Thursday, a secondary trough will deepen across the Pacific Northwest. This pattern will keep increased west to southwesterly gradients across much of Pacific Northwest into the Great Basin and Northern Rockies, with enhanced mid-level flow continuing to overspread these regions. Surface winds across northern Montana will be around 20-25 mph with relative humidity reductions to around 20-25 percent. Across central Wyoming, sustained winds around 20 mph will overlap afternoon relative humidity reductions to around 10-15 percent. Both of these regions have seen drying of fuels in recent windy/dry periods. However, ERCs remain largely at or below seasonal normals. Meteorological conditions will continue to be supportive of large fire growth and further drying of fuels, which supports maintaining an Elevated risk across Montana and introduction of an Elevated risk across central/southern Wyoming with this outlook. ...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 0233 PM CDT Wed Aug 30 2023 Valid 302000Z - 311200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE COASTAL CAROLINAS IN ASSOCIATION WITH TROPICAL CYCLONE IDALIA... ...SUMMARY... A few tornadoes are expected through tonight mainly across the coastal Carolinas in association with Hurricane Idalia. ...Carolinas... The center of T.C. Idalia is forecast to move northeastward along the coastal counties of SC through tonight, and toward the Wilmington NC area by Thursday morning. Observations indicate upper 70s F dewpoints already in place across these areas, with broken bands of cells developing over the ocean and proceeding northwestward over land. Low-level shear will remain strong and favorable for tornadic supercells with 0-1 SRH values of 200-300 m2/s2 developing northeastward ahead of the storm center. For more information see mesoscale discussion 2066. Tornado watch 662 remains in effect. ..Jewell.. 08/30/2023 .PREV DISCUSSION... /ISSUED 1126 AM CDT Wed Aug 30 2023/ ...Southeast Atlantic coast through tonight... The weakening remnants of Hurricane Idalia are forecast to continue moving northeastward near the southeast Atlantic coast through tonight (see latest NHC advisories for additional information). Flow will continue to veer and weaken across central/north FL and the tornado threat will likewise diminish through the afternoon. Farther north, more backed low-level flow and larger, curved hodographs (effective SRH 300-400 m2/s2) are expected in advance of Idalia's core across some of southeast GA and coastal SC this afternoon. Inland rainfall will reinforce a coastal baroclinic zone which will help focus the tornado threat near and just inland from the coast where surface-based buoyancy will be largest, as outer rain band supercells move inland. A similar environment and attendant tornado threat will spread northeastward across coastal NC late this afternoon through tonight. ...New England this afternoon... A pronounced midlevel trough will move over New England this afternoon along with an associated surface cold front. There will be a narrow zone of destabilization along the front, where weak bands of convection will be possible with a very low chance of wind damage given the moderately strong midlevel flow. However, will not add an outlook area since the window of opportunity will be small and confidence in storm development is relatively low. ...Eastern MT/western ND this afternoon/evening... A midlevel shortwave trough will progress eastward from the northern Rockies to the northern High Plains, and this midlevel trough will be preceded by a surface trough/cold front. Some high-based convection could occur along the front in the limited-moisture environment, and this convection could produce gusty outflow winds. The chance for severe outflow winds appears relatively low, precluding the need for an outlook area. Read more

WW 0661 Status Updates
STATUS REPORT ON WW 661 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 60 ENE SSI TO 25 NNE SSI TO 25 W SAV. PARTS OF REMAINING VALID PORTION OF WW ARE BEING LOCALLY EXTENDED IN TIME FOR AN HOUR OR SO. ..KERR..08/30/23 ATTN...WFO...JAX...MLB...TBW...TAE...CHS...FFC... STATUS REPORT FOR WT 661 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS GAC029-031-051-103-109-179-183-191-251-267-301900- GA . GEORGIA COUNTIES INCLUDED ARE BRYAN BULLOCH CHATHAM EFFINGHAM EVANS LIBERTY LONG MCINTOSH SCREVEN TATTNALL AMZ354-301900- CW . ADJACENT COASTAL WATERS INCLUDED ARE COASTAL WATERS FROM SAVANNAH GA TO ALTAMAHA SOUND GA OUT 20 NM ...INCLUDING GRAYS REEF NATIONAL MARINE SANCTUARY THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL Read more

WW 0659 Status Updates
STATUS REPORT ON WW 659 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..08/29/23 ATTN...WFO...MSO...TFX... STATUS REPORT FOR WS 659 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IDC035-049-059-292340- ID . IDAHO COUNTIES INCLUDED ARE CLEARWATER IDAHO LEMHI MTC001-023-039-057-063-077-081-093-292340- MT . MONTANA COUNTIES INCLUDED ARE BEAVERHEAD DEER LODGE GRANITE MADISON MISSOULA POWELL RAVALLI SILVER BOW THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 659 SEVERE TSTM ID MT 292055Z - 300300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 659 NWS Storm Prediction Center Norman OK 255 PM MDT Tue Aug 29 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Idaho Southwest Montana * Effective this Tuesday afternoon and evening from 255 PM until 900 PM MDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...Scattered thunderstorms will form and spread northeastward across northeast Idaho and southwest Montana through late evening. Storm clusters and short line segments will be capable of producing damaging outflow gusts of 60-70 mph and isolated large hail up to 1 inch in diameter. The severe thunderstorm watch area is approximately along and 75 statute miles east and west of a line from 55 miles west northwest of Drummond MT to 45 miles southeast of Salmon ID. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24025. ...Thompson Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0428 PM CDT Tue Aug 29 2023 Valid 311200Z - 061200Z Some dry and breezy post-frontal conditions are expected across northern and eastern Montana on Thursday in a region which is expected to get minimal precipitation tonight and Wednesday. Therefore, fuels should remain dry and favorable for large fire spread on Thursday. Windy conditions are expected to continue from the Great Basin into the central Rockies for much of the extended period as moderate southwesterly mid-level flow persists across the region. However, fuels in this region are mostly moist. In addition, by this weekend, some monsoon moisture will lift northeast and relative humidity will increase with increasing wetting rain/wet thunderstorm chances. In addition, dry and breezy conditions are likely across the Plains and into the Upper Midwest Thursday through the weekend. Fuels are not dry at this time, but after several days of dry and breezy conditions, fuels may become more receptive by this weekend. Fuel states will continue to be monitored as this weekend approaches. ..Bentley.. 08/29/2023 ...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 Tue Aug 29 2023 Valid 311200Z - 061200Z Some dry and breezy post-frontal conditions are expected across northern and eastern Montana on Thursday in a region which is expected to get minimal precipitation tonight and Wednesday. Therefore, fuels should remain dry and favorable for large fire spread on Thursday. Windy conditions are expected to continue from the Great Basin into the central Rockies for much of the extended period as moderate southwesterly mid-level flow persists across the region. However, fuels in this region are mostly moist. In addition, by this weekend, some monsoon moisture will lift northeast and relative humidity will increase with increasing wetting rain/wet thunderstorm chances. In addition, dry and breezy conditions are likely across the Plains and into the Upper Midwest Thursday through the weekend. Fuels are not dry at this time, but after several days of dry and breezy conditions, fuels may become more receptive by this weekend. Fuel states will continue to be monitored as this weekend approaches. ..Bentley.. 08/29/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2059 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF EASTERN WA/OR...CENTRAL ID AND WESTERN MT
Mesoscale Discussion 2059 NWS Storm Prediction Center Norman OK 0331 PM CDT Tue Aug 29 2023 Areas affected...portions of eastern WA/OR...central ID and western MT Concerning...Severe potential...Watch possible Valid 292031Z - 292230Z Probability of Watch Issuance...40 percent SUMMARY...Scattered high-based convection should develop through the afternoon with a risk for damaging outflow winds and hail into the early evening hours. Scattered storm coverage and the potential for gusts to 70 mph suggests a WW is possible. DISCUSSION...Across portions of the Pacific Northwest, regional WV imagery showed a negatively tilted mid-level trough and jet streak ejecting eastward into portions of the northern Rockies. Ahead of the trough, broad synoptic ascent was evident in a deepening convective arc stretching from eastern WA/OR into portions of central ID. Despite limited surface moisture, (surface dewpoints in the 30s and 40s F), strong diurnal surface heating and cooling aloft are supporting 500-1000 J/kg of MLCAPE. As forcing for ascent continues through the afternoon, the sufficient buoyancy should allow for continued updraft development off of local terrain circulations. Scattered high-based storms should mature through the afternoon and continue into the early evening. As the trough and jet streak shift eastward, stronger mid-level flow will overspread the developing storms. Area RAP soundings show deep-layer shear of 30-40 kt which would favor some storm organization. A few longer-lived updrafts or clusters, including weak supercell structures, may evolve given the favorable shear and CAPE. With low-level inverted-v profiles present, strong negatively buoyant downdrafts capable of damaging gusts to 60-70 mph are possible. Small hail is also possible with the more sustained storms. As storms continue to develop, severe potential will likely increase over central and northeastern ID, into western MT this evening. Uncertainty on the severity of the threat is still relatively high given the modest buoyancy, but conditions will be monitored for a possible weather watch. ..Lyons/Thompson.. 08/29/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TFX...PIH...MSO...BOI...OTX...PDT... LAT...LON 44161184 43621273 43531359 44311599 45731761 47051768 48021582 47801386 46711288 45641214 44551173 44161184 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Tue Aug 29 2023 Valid 292000Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF FLORIDA IN ASSOCIATION WITH HURRICANE IDALIA...AND CENTERED OVER THE BITTERROOTS... ...SUMMARY... A few tornadoes will be possible late this afternoon through tonight, mainly from the west central Florida Peninsula into the Big Bend area, within the northeast quadrant of strengthening Hurricane Idalia. Occasional damaging wind gusts will be possible across the northern Rockies. ...20Z Update... Little change was made to the existing severe probabilities at 20Z, except for a minor eastward shift for a low wind threat into central MT where minimal instability will develop due to steepening lapse rates. For the Southeast, the threat for a few tornadoes will increase tonight, primarily after 03Z as stronger shear associated with Hurricane Idalia overspreads parts of the western FL Peninsula, and eventually into parts of the Big Bend. ..Jewell.. 08/29/2023 .PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Aug 29 2023/ ...FL Gulf coast through tonight... Hurricane Idalia is strengthening as of midday over the southeast Gulf of Mexico and is forecast to make landfall Wednesday morning near the FL Big Bend as a major hurricane (please see latest NHC advisories for additional information). Storm motion will be largely parallel to the FL west coast into early tonight, so eastward expansion of the stronger wind field and more favorable low-level hodograph structures will be a gradual process (per the trends in the VWPs from Key West and Tampa). Surface observations show 77-80 F dewpoints across almost all of central/south FL, which will help maintain surface-based buoyancy into this evening and overnight. Thus, the primary increase in supercell/tornado threat is expected late this afternoon into tonight from near Tampa northward along the coast with the more cellular convection within the outer eastern/northeastern bands. ...Northern Rockies this afternoon/evening... A midlevel shortwave trough now over far northern CA and OR will progress east-northeastward toward the northern Rockies by this evening. Though low-level moisture is rather limited, strong surface heating/deep mixing will result in inverted-V profiles with weak buoyancy in advance of the midlevel trough and an associated cold front. Thunderstorm development is expected this afternoon through early tonight in the zone of ascent preceding the midlevel trough (and along the front). The highest confidence in storm development coincident with the steep low-level lapse rates and some enhancement to midlevel flow will be later this afternoon over the Bitterroots, where a few damaging outflow gusts of 60-70 mph will be possible. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Tue Aug 29 2023 Valid 292000Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF FLORIDA IN ASSOCIATION WITH HURRICANE IDALIA...AND CENTERED OVER THE BITTERROOTS... ...SUMMARY... A few tornadoes will be possible late this afternoon through tonight, mainly from the west central Florida Peninsula into the Big Bend area, within the northeast quadrant of strengthening Hurricane Idalia. Occasional damaging wind gusts will be possible across the northern Rockies. ...20Z Update... Little change was made to the existing severe probabilities at 20Z, except for a minor eastward shift for a low wind threat into central MT where minimal instability will develop due to steepening lapse rates. For the Southeast, the threat for a few tornadoes will increase tonight, primarily after 03Z as stronger shear associated with Hurricane Idalia overspreads parts of the western FL Peninsula, and eventually into parts of the Big Bend. ..Jewell.. 08/29/2023 .PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Aug 29 2023/ ...FL Gulf coast through tonight... Hurricane Idalia is strengthening as of midday over the southeast Gulf of Mexico and is forecast to make landfall Wednesday morning near the FL Big Bend as a major hurricane (please see latest NHC advisories for additional information). Storm motion will be largely parallel to the FL west coast into early tonight, so eastward expansion of the stronger wind field and more favorable low-level hodograph structures will be a gradual process (per the trends in the VWPs from Key West and Tampa). Surface observations show 77-80 F dewpoints across almost all of central/south FL, which will help maintain surface-based buoyancy into this evening and overnight. Thus, the primary increase in supercell/tornado threat is expected late this afternoon into tonight from near Tampa northward along the coast with the more cellular convection within the outer eastern/northeastern bands. ...Northern Rockies this afternoon/evening... A midlevel shortwave trough now over far northern CA and OR will progress east-northeastward toward the northern Rockies by this evening. Though low-level moisture is rather limited, strong surface heating/deep mixing will result in inverted-V profiles with weak buoyancy in advance of the midlevel trough and an associated cold front. Thunderstorm development is expected this afternoon through early tonight in the zone of ascent preceding the midlevel trough (and along the front). The highest confidence in storm development coincident with the steep low-level lapse rates and some enhancement to midlevel flow will be later this afternoon over the Bitterroots, where a few damaging outflow gusts of 60-70 mph will be possible. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 PM CDT Tue Aug 29 2023 Valid 301200Z - 311200Z Added an Elevated area for the Snake River Valley where winds of 20 to 25 mph and relative humidity of 15 to 20 percent are expected tomorrow. Fine fuels have started to dry in the region and will be increasingly susceptible to large fire, especially after dry and breezy conditions today. Also added an Elevated area across much of southern and eastern Wyoming. Winds of 20 to 30 mph with some gusts to 35 mph are expected across Wyoming tomorrow. Fuels in this area are not excessively dry, but given the high-end critical meteorological conditions, felt an Elevated delineation is warranted. Elsewhere no changes were needed. See previous discussion below. ..Bentley.. 08/29/2023 .PREV DISCUSSION... /ISSUED 0146 AM CDT Tue Aug 29 2023/ ...Synopsis... Two regions of Elevated fire weather conditions will be possible on Wednesday. Across portions of northern Montana, post frontal northerly flow will overlap drying fuels and relative humidity reductions to around 15-25 percent. Though fuels within this region are drying, they remain too moist to support inclusion of a Critical region at this time. Across the southern US, a tropical system impacting the Gulf of Mexico will bring an increase in northerly gradients across portions of Texas, Louisiana, Arkansas, and Mississippi. Areas across eastern Texas, northern Louisiana, and western Mississippi have seen prolonged heat and drought conditions, which has resulted in explosive fire behavior under more marginal meteorological conditions due to extremely critically dry fuels. Some questions remains how recent rainfall and any potential additional rainfall in the coming 24 hours will change the status of fuels. Given potential for sustained winds around 10-15 mph and relative humidity as low as 20 percent, an Elevated delineation was maintained with this outlook with a slight extension further south in Texas/Louisiana. This area will need to be monitored for Critical highlights in future outlook updates. ...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 0200 PM CDT Tue Aug 29 2023 Valid 301200Z - 311200Z Added an Elevated area for the Snake River Valley where winds of 20 to 25 mph and relative humidity of 15 to 20 percent are expected tomorrow. Fine fuels have started to dry in the region and will be increasingly susceptible to large fire, especially after dry and breezy conditions today. Also added an Elevated area across much of southern and eastern Wyoming. Winds of 20 to 30 mph with some gusts to 35 mph are expected across Wyoming tomorrow. Fuels in this area are not excessively dry, but given the high-end critical meteorological conditions, felt an Elevated delineation is warranted. Elsewhere no changes were needed. See previous discussion below. ..Bentley.. 08/29/2023 .PREV DISCUSSION... /ISSUED 0146 AM CDT Tue Aug 29 2023/ ...Synopsis... Two regions of Elevated fire weather conditions will be possible on Wednesday. Across portions of northern Montana, post frontal northerly flow will overlap drying fuels and relative humidity reductions to around 15-25 percent. Though fuels within this region are drying, they remain too moist to support inclusion of a Critical region at this time. Across the southern US, a tropical system impacting the Gulf of Mexico will bring an increase in northerly gradients across portions of Texas, Louisiana, Arkansas, and Mississippi. Areas across eastern Texas, northern Louisiana, and western Mississippi have seen prolonged heat and drought conditions, which has resulted in explosive fire behavior under more marginal meteorological conditions due to extremely critically dry fuels. Some questions remains how recent rainfall and any potential additional rainfall in the coming 24 hours will change the status of fuels. Given potential for sustained winds around 10-15 mph and relative humidity as low as 20 percent, an Elevated delineation was maintained with this outlook with a slight extension further south in Texas/Louisiana. This area will need to be monitored for Critical highlights in future outlook updates. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Mon Aug 28 21:42:02 UTC 2023.

No Mesoscale Discussions are in effect as of Mon Aug 28 21:42:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CDT Mon Aug 28 2023 Valid 301200Z - 051200Z Tropical storm (soon to be hurricane) Idalia will move into the Southeast on Wednesday bringing strong winds and heavy rain to much of Georgia and Florida, into the Carolinas. On the western periphery of this tropical system, dry northerly winds may result in some elevated to critical fire conditions in drought stricken regions from central Texas to western Mississippi. An amplifying mid-level trough will cross Montana on Wednesday with a surface low and cold front also traversing the state. In the wake of this cold front, dry and breezy westerly flow is expected across northern and eastern Montana. Some dry and breezy conditions are expected in a similar region on Thursday, but rainfall Wednesday night and Thursday may result in some wetting rain and limit fire weather concerns, at least for some portions of north-central and eastern Montana. Several days of dry and breezy conditions are expected from Nevada to Wyoming beneath moderate mid-level flow and a deeply mixed airmass. However, fuels across this region do not support significant fire spread due to recent precipitation. ..Bentley.. 08/28/2023 ...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 0245 PM CDT Mon Aug 28 2023 Valid 282000Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON ACROSS PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated storms capable of strong and gusty winds are possible across the Southeast this afternoon. ...20Z Update... ...Southeast... 18Z soundings sampled a moist, moderately buoyant, and weakly sheared environment across the region. This matches the overall expectation outlined in the previous outlook (appended below), with a predominantly disorganized multicellular storm mode anticipated. Isolated water-loaded downbursts remain possible, particularly from southern MS and across much of AL where the highest storm coverage is anticipated. ...Central/Southern High Plains... Convective initiation has already occurred across the high terrain, with southeastward motion still expected to take these storms into the High Plains. Mesoanalysis estimated effective bulk shear is already 20 to 25 kt across the region, with some additional increase anticipated throughout the afternoon. As such, some organization is possible, with an attendant threat for a strong gust or two. Overall coverage is still expected to remain too low for an outlook area. ..Mosier.. 08/28/2023 .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Aug 28 2023/ ...Southeast this afternoon... A weak midlevel trough persists from the northern Gulf of Mexico to the southern Appalachians with multiple embedded vorticity maxima. Vertical shear is very weak across the Southeast, and thermodynamic profiles are less favorable for strong downdrafts compared to previous days. Thus, scattered pulse-type storms are expected this afternoon along a combination of a stalled synoptic front, weak differential heating zones and local sea breeze circulations. The wind-damage threat appears to be on the lower margins for an outlook area, but will maintain the 5% area for the possibility of isolated downbursts. ...Central/southern High Plains this afternoon/evening... Similar to yesterday, a few storm clusters will form this afternoon and move south-southeastward from southeast WY across eastern CO into eastern NM through this evening. Effective bulk shear of 25-30 kt will support semi-organized storms, a few of which could produce gusty outflow winds and small hail. However, the storms will be relatively low topped for late summer and the severe threat appears too marginal to add an outlook area. ...Tropical cyclone Idalia and FL... Tropical storm Idalia is expected to become a hurricane later today into tonight while moving northward toward the southeast Gulf of Mexico (please refer to latest NHC advisories for additional information). The stronger wind profiles and associated supercell threat will likely be delayed in FL until Tuesday during the day, so will not add any tornado probabilities in this update. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0245 PM CDT Mon Aug 28 2023 Valid 291200Z - 301200Z CORRECTED FOR INCORRECT GRAPHIC An Elevated fire-weather area has been added for southwest Idaho and vicinity where winds of 25 to 30 mph and single digit relative humidity are expected. Much of the Great Basin fuels are too moist to support fire spread. However, across southwest Idaho, there was less recent rainfall and therefore, fuels may be at least somewhat susceptible to large fire, especially given the very windy and dry conditions anticipated. No changes were made elsewhere. See previous discussion below. ..Bentley.. 08/28/2023 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon Aug 28 2023/ ...Synopsis... On Tuesday, a trough will bring an increase in shower and thunderstorm activity across the Pacific Northwest, along with pre-frontal breezy conditions across portions Montana. Across the Southern Plains pressure gradients will increase between the Southwest high and a tropical system impacting the Gulf of Mexico, leading to an increase in surface winds. ...North-Central Texas and Southern Oklahoma... Winds speeds will increase to around 10-15 mph Tuesday afternoon across portions of north-central Texas and southern Oklahoma amid afternoon relative humidity reductions to around 20-30 percent. Fuels within this region remain critically dry, as very little rain has fallen across this region in the last 7 days and prolonged drought has led to drought stress. Given that relative humidity looks to largely stay above Critical thresholds, an Elevated delineation should cover the larger threat well. ...North-Central Montana... Pre-frontal winds will increase to around 15-20 mph amid relative humidity reductions to around 20-25 percent across north-central Montana Tuesday afternoon. Fuels within this region have experienced some drying due to lack of recent rainfall. However, fuels largely remain at or below average precluding the need for Critical highlights and as such an Elevated delineation was most appropriate. ...Dry Thunderstorms... An increase in shower and thunderstorm chances is possible across the Pacific Northwest on Tuesday. Precipitable water values across eastern Washington, northern Idaho, and western Montana will range around 0.50-1.00" with potential for fast storm motions. This will likely result in a mix of wet and dry thunderstorm activity. Ensemble data from the HREF indicates the more appreciable rainfall may be more likely across northern Idaho/western Montana with amounts generally up to and less than 0.10" across eastern Washington across the Cascades and central Columbia Basin. This will need to be monitored for inclusion of isolated dry thunderstorms. For now, confidence remains low in exactly which areas will remain mostly dry. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Aug 28 2023 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHWEST/WEST-CENTRAL FLORIDA PENINSULA... ...SUMMARY... The potential for a few tornadoes should gradually increase along/near parts of the Florida Gulf Coast and into north Florida through Tuesday night as Tropical Cyclone Idalia approaches. ...Florida into Southeast Georgia... Latest forecast for TC Idalia centers the system northwest of western Cuba early Tuesday morning, with northeastward/north-northeastward motion taking the storm to just off northwestern FL Peninsula by 12Z Wednesday morning. Strong low/mid-level flow associated with this system will gradually spread northward across the FL Peninsula throughout the day, with the strongest winds expected along the western coast after 00Z. Rain bands will likely begin moving across the peninsula during the early afternoon, with a generally northeastward storm motion anticipated. Lapse rates will be poor, but the moist airmass across the region will still support moderate buoyancy and the potential for a few strong updrafts. The most significant increases in low-level shear are not expected under after 00Z, so the severe-gust and tornado potential with these multicellular bands will be low, but not zero. After 00Z through the remainder of the period, strengthening low to mid-level flow will result in a gradually increasing tornado potential, particular along the west-central and northwest portions of the FL Peninsula. TC tornado climatology shows a notable preference for tornadoes between 200-300 km northeast of the center for northeastward progressing major hurricanes. This matches well with the most favorable environmental conditions for tornadogenesis in this case, which are along the northwest/west-central FL coast from 06Z-12Z. ...Interior Pacific Northwest into the Northern Rockies... A negatively tilted shortwave trough is forecast to progress across the Pacific Northwest on Tuesday. Moderate mid-level flow and moisture will spread eastward ahead of this wave across ID and into western MT. Resulting combination of a deeply mixed boundary layer, increasing mid-level moisture, and strengthening ascent is expected to result in afternoon/evening thunderstorm development. 20 to 30 kt of effective shear will help organize some updrafts, with high cloud bases and steep low-level lapse rates supporting the potential for strong outflow. An instance or two of hail is possible as well. ...Great Lakes/OH Valley... A cold front is forecast move southeastward across the Great Lakes and parts of the Midwest/OH Valley, in tandem with an eastward-moving upper trough. Dewpoints will likely be in the upper 50s and low 60s from IL into IN and MI ahead of this front, but mid-level temperatures will be relatively warm, limiting buoyancy and updraft strength/duration. Damaging gusts would be possible with any deep, sustained updrafts, but the overall probability of occurrence currently appears low. ...Appalachians... Scattered thunderstorms should develop across parts of the southern/central Appalachians Tuesday afternoon, as modest ascent associated with an upper trough moving Quebec and the Upper Great Lakes/OH Valley glances the region. Modest deep-layer vertical shear is anticipated amid the southwesterly mid-level flow stretching across the region, supporting potential updraft organization. Even so, poor lapse rates should limit instability and overall updraft strength. A generally multicellular, outflow-dominant storm mode is anticipated, and the potential for a damaging gust or two exists within any bowing segments. However, overall severe coverage is expected to remain too low to include severe probabilities. ..Mosier.. 08/28/2023 Read more

No watches are valid as of Sun Aug 27 22:22:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0454 PM CDT Sun Aug 27 2023 Valid 291200Z - 041200Z ...D3/Tue - D4/Wed - Southern Plains... Dry and breezy conditions will develop in the northerly flow between the high pressure in the High Plains and the tropical system in the Gulf of Mexico. Thunderstorms Saturday and Sunday likely provided wetting rains for some locations, but others will still have exceptionally dry fuels. ......D3/Tue - Montana... There will be some potential for critical fire weather conditions on Tuesday across portions of northern Montana. Pre-frontal winds are expected to be strongest across portions of north-central Montana where minimal precipitation fell last week. Therefore, 40 percent probabilities have been added for the increasing threat for elevated to critical fire weather conditions across north-central Montana on Tuesday. ...D3/Tue - D4/Wed - Northwest... A negatively tilted mid-level trough will move across the Pacific Northwest on Tuesday. This will bring numerous thunderstorms, particularly across Washington. PWAT values are expected to be around 1 inch with storms likely more wet. However, storm speeds will be in excess of 30 mph, which could increase the threat for dry thunderstorms somewhat. Nonetheless, no dry thunderstorm probabilities have been added due to the questions regarding storm wetness and only marginally dry fuels east of the Cascades where storms may be more dry. As this trough advances east, some breezy conditions are expected in the Columbia Basin. The significant moisture surge with this system may keep relative humidity higher and thus keep the fire weather threat somewhat more subdued than otherwise may be expected. At this time, no 40 percent probabilities have been added as relative humidity is forecast to stay 30%+ where fuel are critically dry. ..Bentley.. 08/27/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more