SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CST Wed Nov 06 2024 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN A PART OF WEST TX... ...SUMMARY... Isolated severe thunderstorms are possible, beginning in the late afternoon Thursday across parts of west and central Texas. The most likely corridor for large hail will be over a part of west Texas on Thursday evening/night. ...West/central TX... A mid/upper low will drift east across AZ/NM through much of the day Thursday. By Thursday night, it should accelerate as an attendant mid-level jet becomes confined to the southeast quadrant of the cyclone. While a surface ridge will initially nose down the southern High Plains from an anticyclone over the central High Plains, this will eventually lose amplitude. Weak cyclogenesis should occur late in the period along an inverted surface trough in parts of west TX. A persistent increase in low-level moisture from the western Gulf will return northwestward through the period. While some elevated convection will be possible during the day, initially from central to northwest TX, the bulk of convective development should occur in the evening/night as the low-level jet broadly intensifies. This will be coincident with a gradual increase in mid-level height falls overspreading west TX Thursday night. A mesoscale corridor of relatively greater supercell potential appears evident during the evening/night. This appears centered on parts of the Lower Pecos Valley/Permian Basin and the western Edwards Plateau regions near the surface trough. While low-level lapse rates should be weak, strong southwesterly speed shear in the mid to upper levels will be favorable for a primary threat of large hail with a mix of cells/small clusters. An abrupt cutoff to surface-based severe convection is expected to the north/west of this corridor, especially as weak cyclogenesis occurs. While consistency has increased in guidance relative to 24 hours, where exactly this demarcation is will likely be modulated by how widespread elevated convection becomes during the evening to night. ..Grams.. 11/06/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CST Wed Nov 06 2024 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN A PART OF WEST TX... ...SUMMARY... Isolated severe thunderstorms are possible, beginning in the late afternoon Thursday across parts of west and central Texas. The most likely corridor for large hail will be over a part of west Texas on Thursday evening/night. ...West/central TX... A mid/upper low will drift east across AZ/NM through much of the day Thursday. By Thursday night, it should accelerate as an attendant mid-level jet becomes confined to the southeast quadrant of the cyclone. While a surface ridge will initially nose down the southern High Plains from an anticyclone over the central High Plains, this will eventually lose amplitude. Weak cyclogenesis should occur late in the period along an inverted surface trough in parts of west TX. A persistent increase in low-level moisture from the western Gulf will return northwestward through the period. While some elevated convection will be possible during the day, initially from central to northwest TX, the bulk of convective development should occur in the evening/night as the low-level jet broadly intensifies. This will be coincident with a gradual increase in mid-level height falls overspreading west TX Thursday night. A mesoscale corridor of relatively greater supercell potential appears evident during the evening/night. This appears centered on parts of the Lower Pecos Valley/Permian Basin and the western Edwards Plateau regions near the surface trough. While low-level lapse rates should be weak, strong southwesterly speed shear in the mid to upper levels will be favorable for a primary threat of large hail with a mix of cells/small clusters. An abrupt cutoff to surface-based severe convection is expected to the north/west of this corridor, especially as weak cyclogenesis occurs. While consistency has increased in guidance relative to 24 hours, where exactly this demarcation is will likely be modulated by how widespread elevated convection becomes during the evening to night. ..Grams.. 11/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Tue Nov 05 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE KEYS AND PORTIONS OF EXTREME SOUTHERN FLORIDA... ...SUMMARY... A couple of brief tornadoes will be possible within outer bands of Hurricane Rafael, from late morning into the evening, across the Keys and the far southern Peninsula of Florida. ...Hurricane Rafael... Dominant Bermuda High will prove instrumental in the upcoming track of Hurricane Rafael. Over the next 36hr, Rafael is forecast to continue its northwest trajectory across Cuba into the southeastern Gulf Basin. Low-level shear will gradually increase across the Keys into extreme southern FL, and outer convective bands will begin to affect this portion of FL, especially later this afternoon/evening. Current track (reference https://www.nhc.noaa.gov) suggests severe probabilities will not need to be expanded north across the Peninsula as strongest shear will remain offshore across the Gulf Basin. Some tornado threat can be expected with strongest, more organized convection, especially across the Keys. ..Darrow/Weinman.. 11/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Tue Nov 05 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE KEYS AND PORTIONS OF EXTREME SOUTHERN FLORIDA... ...SUMMARY... A couple of brief tornadoes will be possible within outer bands of Hurricane Rafael, from late morning into the evening, across the Keys and the far southern Peninsula of Florida. ...Hurricane Rafael... Dominant Bermuda High will prove instrumental in the upcoming track of Hurricane Rafael. Over the next 36hr, Rafael is forecast to continue its northwest trajectory across Cuba into the southeastern Gulf Basin. Low-level shear will gradually increase across the Keys into extreme southern FL, and outer convective bands will begin to affect this portion of FL, especially later this afternoon/evening. Current track (reference https://www.nhc.noaa.gov) suggests severe probabilities will not need to be expanded north across the Peninsula as strongest shear will remain offshore across the Gulf Basin. Some tornado threat can be expected with strongest, more organized convection, especially across the Keys. ..Darrow/Weinman.. 11/06/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0634 PM CST Tue Nov 05 2024 Valid 060100Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected overnight. ...01z Update... Strong short-wave trough continues ejecting northeast across the upper Great Lakes region early this evening. This feature will top the eastern US ridge over southern ON/QC toward sunrise, as the next strong upper trough digs into the Four Corners. Associated surface front has stalled across lower latitudes, but will continue to advance into the OH Valley into the early parts of the day2 period. As the primary focus for large-scale ascent shifts north of the international border, lack of focus along the trailing front should lead to only weak, and mostly shallow convection. While a few updrafts may penetrate levels necessary for lightning discharge, conditions do not currently warrant severe probabilities the rest of tonight. ..Darrow.. 11/06/2024 Read more

No watches are valid as of Tue Nov 5 22:01:01 UTC 2024.

No Mesoscale Discussions are in effect as of Tue Nov 5 22:01:01 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0354 PM CST Tue Nov 05 2024 Valid 071200Z - 131200Z An active mid-level flow regime is likely to continue over the CONUS through the extended forecast period. Strong troughing over the western US will gradually shift eastward this weekend, followed by shortwave ridging. By early next week, the upper ridge will break down, allowing stronger jet energy to move back over the West ahead of a deepening Pacific trough. This active and progressive flow pattern will continue through the end of the period, supporting the potential for critical fire-weather over parts of California. ...Southern California... On the backside of the strong trough, northerly flow will linger over southern California D3/Thursday into early D4/Friday. Offshore winds will remain fairly strong early in the period before weakening rapidly into this weekend. As the winds gradually fade, very low humidity should persist into the first part of the weekend. This may keep some risk for localized fire-weather concerns through D6/Sunday across parts of southern California. Later in the weekend and into early next week, onshore flow will return, increasing RH as a progressive, low-latitude flow regime persists. Fire-weather concerns will lessen temporarily before potentially returning ahead of another deepening trough midweek next week. Medium-range guidance shows the potential for a period of offshore winds behind the large Pacific trough into week 2. Strong winds and very low relative humidity could overlap with very dry and dense fuels across much of southern California. Model guidance varies enough on the magnitude and timing of the onset of offshore winds that probabilities will be withheld for the time being. However, significant fire-weather concerns are possible at the end of the extended forecast period and through next week. ..Lyons.. 11/05/2024 ...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 0354 PM CST Tue Nov 05 2024 Valid 071200Z - 131200Z An active mid-level flow regime is likely to continue over the CONUS through the extended forecast period. Strong troughing over the western US will gradually shift eastward this weekend, followed by shortwave ridging. By early next week, the upper ridge will break down, allowing stronger jet energy to move back over the West ahead of a deepening Pacific trough. This active and progressive flow pattern will continue through the end of the period, supporting the potential for critical fire-weather over parts of California. ...Southern California... On the backside of the strong trough, northerly flow will linger over southern California D3/Thursday into early D4/Friday. Offshore winds will remain fairly strong early in the period before weakening rapidly into this weekend. As the winds gradually fade, very low humidity should persist into the first part of the weekend. This may keep some risk for localized fire-weather concerns through D6/Sunday across parts of southern California. Later in the weekend and into early next week, onshore flow will return, increasing RH as a progressive, low-latitude flow regime persists. Fire-weather concerns will lessen temporarily before potentially returning ahead of another deepening trough midweek next week. Medium-range guidance shows the potential for a period of offshore winds behind the large Pacific trough into week 2. Strong winds and very low relative humidity could overlap with very dry and dense fuels across much of southern California. Model guidance varies enough on the magnitude and timing of the onset of offshore winds that probabilities will be withheld for the time being. However, significant fire-weather concerns are possible at the end of the extended forecast period and through next week. ..Lyons.. 11/05/2024 ...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 0157 PM CST Tue Nov 05 2024 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF SOUTHERN WISCONSIN AND FROM THE LOWER OHIO VALLEY INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Locally damaging winds and perhaps a tornado or two may occur across a portion of the Lower and Mid Mississippi Valleys, and central to southern Wisconsin. ...20Z Update... With the primary mid-level forcing moving away from the ArkLaMiss, storm coverage should generally remain more isolated through the remainder of the afternoon. Furthermore, regional VAD profiles suggest low-level shear have been decreasing with time. Given these observational trends, tornado probabilities have been reduced in the region. The marginal risk across Wisconsin has been adjusted based on surface observations. A line of shallow convection moving east through western Wisconsin may produce isolated strong/damaging winds as it moves into areas where at least muted heating has occurred. KMKX VAD suggests strong enough flow in the lowest 1-2 km to support this risk. ..Wendt.. 11/05/2024 .PREV DISCUSSION... /ISSUED 1019 AM CST Tue Nov 05 2024/ ...LA/MS... A large upper trough is present today over the central US, with the primary surface boundary extending from eastern AR southward into central LA. Scattered thunderstorms have been occurring along and ahead of this boundary, including several storms exhibiting low and mid level rotation. Winds aloft are expected to weaken through the day, but there is a continued chance of isolated tornadoes for a few hours late this morning and early afternoon. Therefore have added a small SLGT risk area. Please refer to MCD #2213 for further details on this environment. ...AR/TN/KY/IN... A narrow line of thunderstorms is noted along the boundary across eastern AR. Several morning CAM solutions suggest this line may maintain some character through the afternoon and it tracks northeastward across parts of the mid MS Valley. Visible satellite imagery shows breaks in the clouds across this region, providing some heating and destabilization. Also, low level wind fields will remain rather strong ahead of the convection. This may be sufficient for locally gusty/damaging wind gusts this afternoon. ....WI... A few low-topped showers and thunderstorms will likely form later this afternoon near a deepening surface low over WI. Widespread clouds will limit destabilization, but there is some potential for locally gusty/damaging winds during the peak-heating period. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0131 PM CST Tue Nov 05 2024 Valid 061200Z - 071200Z ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR NORTHERN LOS ANGELES AND SOUTHERN VENTURA COUNTIES... ...CRITICAL FIRE WEATHER AREA FOR MUCH OF SOUTHERN CALIFORNIA... ...Afternoon Update... Confidence remains high that a strong offshore wind event will develop across much of southern California beginning early Wednesday and continuing into Thursday morning. Santa Ana winds with isolated gusts to 60 mph are possible across Los Angeles and Ventura counties. These strong winds will overlap with very low RH as low as 8-10% supporting extremely critical fire-weather conditions. The latest CANSAC WRF also shows strong offshore winds developing across portions of Orange and San Diego counties Wednesday afternoon and continuing through early Thursday. While offshore gradients are not as strong, gusts of 40-50 mph and RH of 10-15% will support several hours of critical fire-weather conditions amidst dry fuels. Have expanded the Critical area across all of coastal Orange/San Diego counties and into portions of the western inland Valleys. See the prior discussion for more information. ..Lyons.. 11/05/2024 .PREV DISCUSSION... /ISSUED 0213 AM CST Tue Nov 05 2024/ ...Synopsis... A mid/upper-level ridge will amplify over the eastern Pacific and CA coast, as a belt of strong midlevel northerly flow extends from the Northwest to southern CA. This large-scale pattern will reinforce a strong surface anticyclone over the Intermountain West, leading to a robust offshore pressure gradient across southern CA. ...Southern California... The offshore pressure gradient will be peaking from the morning into the afternoon/evening time frame, with most guidance depicting a LAX-TPH pressure gradient less than -13 mb and LAX-DAG gradient less than -6 mb -- both indicating a strong Santa Ana event across southern CA. This pressure gradient, combined with the strong deep-layer northerly flow directed toward the coast, will promote 30+ mph sustained northeasterly surface winds across the typical wind-prone Santa Ana corridors. Over the wind-prone mountains and valleys of southern Ventura and northern/northwestern Los Angeles Counties, gusts of 60+ mph will combine with RH decreasing into the lower teens/single digits for several hours -- leading to extremely critical fire-weather conditions atop receptive fuels. ...Northern/Central California... The tightening pressure gradient and strong deep-layer northerly flow will yield another day of breezy/gusty northerly surface winds amid low RH across the western Sacramento Valley into the Coastal Range. Given modestly receptive fuels, elevated to locally critical fire-weather conditions are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Tue Nov 05 2024 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF CENTRAL/WEST-CENTRAL TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible, beginning Thursday afternoon across central/west-central parts of Texas. ...TX... A mid- to upper-level low will meander slowly east across the Desert Southwest during the period. In between a surface high centered over the central High Plains and TC Rafael in the Gulf of Mexico, easterly low-level flow in the western Gulf Basin and TX will favor a gradual westward push of modified moisture return into west-central TX. A surface trough will likely serve as the western delimiter of moisture/instability. Models indicate at least weak to moderate buoyancy developing by mid-late afternoon in the Concho Valley. Shear profiles will support storm organization, including the possibility for supercells. Have made a small westward adjustment to low-severe probabilities over west-central TX based on the latest model guidance. Large hail appears to be the primary threat, although a confined zone may exhibit a short-duration threat for a tornado. A hail/wind risk could linger well into the evening and perhaps early overnight depending on storm-scale details unknown/not resolvable at this time. ..Smith.. 11/05/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CST Tue Nov 05 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN THE LOWER FLORIDA KEYS... ...SUMMARY... A couple of brief tornadoes will be possible within outer bands of Tropical Cyclone Rafael, from late morning into the evening Wednesday across the Keys and the far southern Peninsula of Florida. ...Keys/southern Peninsula of FL... Tropical Cyclone Rafael is forecast to move northwestward across western Cuba and into the southeastern Gulf of Mexico Wednesday night per the latest National Hurricane Center forecast. Low-level flow fields are forecast to strengthen across the Florida Straits and Keys, with hodographs enlarging through early evening. This increase should be favorably timed to the diurnal heating cycle, with peak low-level SRH anticipated during the late afternoon. Mid to upper 70s surface dewpoints will contribute to buoyancy sufficient for some of the stronger updrafts to intermittently rotate with a couple of tornadoes possible. The tornado threat will probably lessen with time Wednesday night as low-level SRH weakens, and deep convection becomes confined to the Gulf. ..Smith.. 11/05/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CST Tue Nov 05 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN THE LOWER FLORIDA KEYS... ...SUMMARY... A couple of brief tornadoes will be possible within outer bands of Tropical Cyclone Rafael, from late morning into the evening Wednesday across the Keys and the far southern Peninsula of Florida. ...Keys/southern Peninsula of FL... Tropical Cyclone Rafael is forecast to move northwestward across western Cuba and into the southeastern Gulf of Mexico Wednesday night per the latest National Hurricane Center forecast. Low-level flow fields are forecast to strengthen across the Florida Straits and Keys, with hodographs enlarging through early evening. This increase should be favorably timed to the diurnal heating cycle, with peak low-level SRH anticipated during the late afternoon. Mid to upper 70s surface dewpoints will contribute to buoyancy sufficient for some of the stronger updrafts to intermittently rotate with a couple of tornadoes possible. The tornado threat will probably lessen with time Wednesday night as low-level SRH weakens, and deep convection becomes confined to the Gulf. ..Smith.. 11/05/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CST Tue Nov 05 2024 Valid 051700Z - 061200Z ...17z Update... Minimal changes have been made to the Elevated area over northern CA. Slightly stronger winds and lower humidity may occur over the higher peaks of the coastal ranges this afternoon and evening. Gusty winds and lower humidity may also extend farther south down the Central Valley. This could support elevated fire-weather conditions for a few hours. The elevated area was shifted slightly south. Across southern CA, offshore pressure gradients should increase overnight Tue into early Wed. Below 15% humidity and winds greater than 20 mph are possible over the Transverse and Peninsular Ranges and sustained Elevated conditions potentially beginning prior to 12z Wed. Thus, have added an Elevated area to better account for the increasing fire-weather threat into early Wed morning. Otherwise, see the previous outlook for more info. ..Lyons.. 11/05/2024 .PREV DISCUSSION... /ISSUED 0208 AM CST Tue Nov 05 2024/ ...Synopsis... On the backside of a broad/amplified large-scale trough centered overt the Rockies, a belt of strong deep-layer northerly flow will overspread CA. At the same time, the surface pressure gradient will tighten over northern/central CA -- along the southern periphery of strengthening surface ridging over the Northwest. This will yield 15-20 mph sustained northerly surface winds (with higher gusts) over portions of the western Sacramento Valley into the Coastal Range. These strong/gusty winds, coupled with 15-20 percent afternoon RH, will favor elevated to locally critical fire-weather conditions. ...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 1019 AM CST Tue Nov 05 2024 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF LOUISIANA.... ...SUMMARY... Locally damaging winds and perhaps a tornado or two may occur across a portion of the Lower and Mid Mississippi Valleys, and central to southern Wisconsin. ...LA/MS... A large upper trough is present today over the central US, with the primary surface boundary extending from eastern AR southward into central LA. Scattered thunderstorms have been occurring along and ahead of this boundary, including several storms exhibiting low and mid level rotation. Winds aloft are expected to weaken through the day, but there is a continued chance of isolated tornadoes for a few hours late this morning and early afternoon. Therefore have added a small SLGT risk area. Please refer to MCD #2213 for further details on this environment. ...AR/TN/KY/IN... A narrow line of thunderstorms is noted along the boundary across eastern AR. Several morning CAM solutions suggest this line may maintain some character through the afternoon and it tracks northeastward across parts of the mid MS Valley. Visible satellite imagery shows breaks in the clouds across this region, providing some heating and destabilization. Also, low level wind fields will remain rather strong ahead of the convection. This may be sufficient for locally gusty/damaging wind gusts this afternoon. ....WI... A few low-topped showers and thunderstorms will likely form later this afternoon near a deepening surface low over WI. Widespread clouds will limit destabilization, but there is some potential for locally gusty/damaging winds during the peak-heating period. ..Hart/Supinie.. 11/05/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0650 AM CST Tue Nov 05 2024 Valid 051300Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS A PORTION OF THE SABINE TO LOWER MISSISSIPPI VALLEYS...AND CENTRAL TO SOUTHERN WISCONSIN... ...SUMMARY... A brief tornado or two and locally damaging winds may occur across a portion of the Sabine to Lower Mississippi Valleys, and central to southern Wisconsin. ...Synopsis... Mid/upper-level longwave troughing has become well-established over the western CONUS. That will persist through this and more outlook periods, as a series of synoptic to large shortwave troughs traverses the associated cyclonic-flow field. The leading such perturbation -- now located from the central Plains south- southwestward over the southern High Plains to far west TX -- will eject northeastward and weaken. By 00Z, the residual, strongly positively tilted trough should extend from a vorticity max over western WI, across central/southwestern MO to central TX. The perturbation will deamplify greatly overnight and accelerate to a position near the western QC/ON border, Lake Huron and IN by 12Z. Meanwhile, an upstream shortwave trough -- evident in moisture- channel imagery over ID -- will dig southeastward and strengthen greatly through the period. By 12Z, it should be oriented northeast/southwest through a developing 500-mb low over the Four Corners. The 11Z surface analysis showed an elongated area of low pressure from southern WI to northwestern MO, with cold front through central OK and north-central/central TX. The front was preceded by an extensive convective band and associated outflow boundary from central IL to central AR, east TX, and deep south TX. By 00Z, the front should catch up (or nearly so) to what remains of the convective boundary, with the combined baroclinic zone extending from a consolidated low over northern WI across the Mid-South region to the northwestern Gulf shelf waters off TX. By 12Z, the front should extend from Lower MI across western portions of KY/TN/MS to southwestern LA and the northwestern Gulf. ...Sabine to Lower Mississippi Valleys... The ongoing convective band, near the western edge of the "Marginal Risk" area, should weaken overall through mid-morning. However, an isolated damaging gust or brief tornado cannot be ruled out in the meantime with any associated or preceding cell that may take advantage of lingering favorable deep shear and high theta-e, in a northward-narrowing corridor. After a relative lull of a few hours, widely scattered to scattered thunderstorms are forecast along the boundary this afternoon into early evening, with isolated damaging gusts and/or a tornado possible. Afternoon boundary-layer destabilization is anticipated ahead of the convective boundary, from both fragmented/cloud- modulated surface heating and low-level theta-e advection. A corridor of surface dewpoints in the upper 60s to low 70s F will persist an expand slightly northward ahead of the boundary. With no antecedent EML and minimal MLCINH, this should offset modest midlevel lapse rates enough to result in effectively uninhibited buoyancy, supporting an increase in convective coverage and local intensity this afternoon. Peak MLCAPE should range from around 500-800 J/kg over a narrow corridor of the Mid-South, widening/increasing to around 1000-1500 J/kg over southern LA. By contrast, lift along the boundary, and in the form of deep-layer ascent preceding the weakening mid/upper trough, will be greater over the Mid-South, until some nebulous point where too little instability exists to support organized convection. The outlook has been elongated northward somewhat to cover the marginal-buoyancy plume near the Mississippi River. ...WI... Isolated to widely scattered, shallow thunderstorms are possible this afternoon, in an arc near the front and the organizing surface low. A few cells may produce damaging gusts. A brief tornado also may occur, especially with any cells that can linger within a narrow zone of overlap between favorably, isallobarically backed near- surface winds and weak boundary-layer instability. A low-confidence and quite conditional scenario exists here, with abundant antecedent clouds and precip likely to limit destabilization for most of the day. Forecast soundings suggest enough large-scale ascent aloft to cool midlevels a degree or two C, though lapse rates still will be meager. Areas that can experience a couple hours of relatively unimpeded heating may attain 250-500 J/kg MLCAPE. ..Edwards/Mosier.. 11/05/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0337 AM CST Tue Nov 05 2024 Valid 081200Z - 131200Z ...DISCUSSION... ...D4-5/Friday-Saturday... Guidance suggests acceleration of the Southwest upper trough should occur across the southern High Plains to central Great Plains. After an initially inverted surface trough on D3/Thursday, surface cyclone development is expected. Overall model trends have been for greater amplification of the trough and attendant surface reflection. But spatial spread, that is noticeable on Thursday, increases further into Friday-Saturday. In addition, very large spread persists with the potential track of TC Rafael in the Gulf. This may render peripheral impacts on the surrounding low-level moisture plume ahead of the Great Plains wave. As such, confidence is low for determining probable mesoscale-focused severe potential on D4-5 across the south-central states. ...D8/Tuesday... After a potential quiet period of severe potential on D6-7, guidance consensus indicates an amplified upper trough should progress into the West early next week. This may eventually overlap a broadening warm/moist sector emanating north from the western Gulf and yield a return to increasing severe potential towards mid-week. Poor run-to-run continuity and large ensemble spread exists with the evolution of this trough for now. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0337 AM CST Tue Nov 05 2024 Valid 081200Z - 131200Z ...DISCUSSION... ...D4-5/Friday-Saturday... Guidance suggests acceleration of the Southwest upper trough should occur across the southern High Plains to central Great Plains. After an initially inverted surface trough on D3/Thursday, surface cyclone development is expected. Overall model trends have been for greater amplification of the trough and attendant surface reflection. But spatial spread, that is noticeable on Thursday, increases further into Friday-Saturday. In addition, very large spread persists with the potential track of TC Rafael in the Gulf. This may render peripheral impacts on the surrounding low-level moisture plume ahead of the Great Plains wave. As such, confidence is low for determining probable mesoscale-focused severe potential on D4-5 across the south-central states. ...D8/Tuesday... After a potential quiet period of severe potential on D6-7, guidance consensus indicates an amplified upper trough should progress into the West early next week. This may eventually overlap a broadening warm/moist sector emanating north from the western Gulf and yield a return to increasing severe potential towards mid-week. Poor run-to-run continuity and large ensemble spread exists with the evolution of this trough for now. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 AM CST Tue Nov 05 2024 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF CENTRAL/WEST-CENTRAL TX... ...SUMMARY... Isolated severe thunderstorms are possible, beginning Thursday afternoon across central/west-central parts of Texas. ...TX... Modified moisture return from the western Gulf will increase across much of TX in advance of a slow-moving mid/upper trough over AZ/NM. A surface anticyclone over the central High Plains will support ridging southward across the southern High Plains, with an inverted trough developing to its east. 00Z models differ substantially in the location of this trough, largely bracketed by a farther east GFS and west ECMWF. This yields longitudinal uncertainty with the potential severe-storm corridor. Much of the convective development will probably be elevated to the cool side of the surface trough. Even so, a threat for severe hail should exist given favorably strong southwesterly speed shear. Surface-based buoyancy should struggle to develop north/west of central TX, ahead of the inverted trough. This may be adequate for a confined corridor of surface-based supercell threat starting Thursday afternoon. Given the spatial uncertainties and relatively nebulous setup, only low severe probabilities appear warranted. ...Central/eastern Gulf Coast... Per the latest NHC forecast and probable compact nature of strong low-level winds surrounding TC Rafael, a coastal tornado threat appears unlikely on Thursday to early Friday. Still, with large spread in guidance regarding the evolution of TC Rafael in the eastern to central Gulf, there remains potential for a tornado-threat highlight during this time frame in later outlooks. ..Grams.. 11/05/2024 Read more