Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Wed May 03 2023 Valid 032000Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH EVENING ACROSS THE PECOS VALLEY AND PERMIAN BASIN OF WEST TEXAS... ...SUMMARY... Isolated large hail and strong-severe outflow winds will be possible through this evening across the Pecos Valley and Permian Basin of west Texas. ...20z Update... A minor adjustment to the Marginal risk has been made over northwest Texas with the 20z update. Isolated convection has developed this afternoon along an outflow-reinforced boundary. Modified RAP soundings with current observations indicate a somewhat more favorable environment exists within the frontal zone compared to earlier forecast guidance. A storm or two may briefly become severe, producing marginal hail and strong gusts. For more info on short term severe potential, see MCD 670. Otherwise, the previous forecast remains on track. For short term severe information across the Trans-Pecos/Permian Basin see MCD 671. ..Leitman.. 05/03/2023 .PREV DISCUSSION... /ISSUED 1111 AM CDT Wed May 03 2023/ ...Southern High Plains this afternoon through late evening... Midlevel ridging will persist over the High Plains, between deep midlevel lows near the central CA coast and over western NY/PA. A convectively enhanced trough and associated elevated convection has moved through the mean ridge, and will continue slowly eastward over southern OK today. The rain/clouds with this wave will reinforce a baroclinic zone just south of the Red River, which will demarcate the northern fringe of the boundary-layer dewpoints above 60 F. Farther west, the flow regime will encourage only weak lee troughing from eastern NM into eastern CO, with modest low-level moisture (dewpoints in the mid 40s to mid 50s) along and east of the weak lee trough. Satellite imagery shows a large area with few/no clouds centered over eastern NM, so strong surface heating/mixing is expected along the lee trough, and in the immediate lee of the higher terrain features such as the Davis/Guadalupe/Sacramento Mountains northward to the Raton Mesa. Weakening convective inhibition and MLCAPE in the 1000-1500 J/kg range will favor high-based thunderstorm development, some of which could be splitting supercells given relatively straight hodographs and effective bulk shear in the 30-35 kt range. The initial/supercells storms will be capable of producing isolated large hail (mainly 1 to 1.75 inches in diameter) and strong/severe outflow gusts. There will be some potential for upscale growth into a small cluster across the South Plains/TX Panhandle tonight as low-level warm advection strengthens, though the severe threat will slowly diminish by late evening. ...Great Basin/Pacific Northwest... Some high-based convection will be possible this afternoon across western UT, around the eastern periphery of the northern CA closed low. Moisture will be limited, but deep inverted-v profiles and minimal buoyancy could support strong outflow winds for a few hours this afternoon/evening. Other isolated strong/elevated storms may occur in the eastern flow regime north of the closed low (along the Cascades), where steep midlevel lapse rates support weak buoyancy. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Wed May 03 2023 Valid 032000Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH EVENING ACROSS THE PECOS VALLEY AND PERMIAN BASIN OF WEST TEXAS... ...SUMMARY... Isolated large hail and strong-severe outflow winds will be possible through this evening across the Pecos Valley and Permian Basin of west Texas. ...20z Update... A minor adjustment to the Marginal risk has been made over northwest Texas with the 20z update. Isolated convection has developed this afternoon along an outflow-reinforced boundary. Modified RAP soundings with current observations indicate a somewhat more favorable environment exists within the frontal zone compared to earlier forecast guidance. A storm or two may briefly become severe, producing marginal hail and strong gusts. For more info on short term severe potential, see MCD 670. Otherwise, the previous forecast remains on track. For short term severe information across the Trans-Pecos/Permian Basin see MCD 671. ..Leitman.. 05/03/2023 .PREV DISCUSSION... /ISSUED 1111 AM CDT Wed May 03 2023/ ...Southern High Plains this afternoon through late evening... Midlevel ridging will persist over the High Plains, between deep midlevel lows near the central CA coast and over western NY/PA. A convectively enhanced trough and associated elevated convection has moved through the mean ridge, and will continue slowly eastward over southern OK today. The rain/clouds with this wave will reinforce a baroclinic zone just south of the Red River, which will demarcate the northern fringe of the boundary-layer dewpoints above 60 F. Farther west, the flow regime will encourage only weak lee troughing from eastern NM into eastern CO, with modest low-level moisture (dewpoints in the mid 40s to mid 50s) along and east of the weak lee trough. Satellite imagery shows a large area with few/no clouds centered over eastern NM, so strong surface heating/mixing is expected along the lee trough, and in the immediate lee of the higher terrain features such as the Davis/Guadalupe/Sacramento Mountains northward to the Raton Mesa. Weakening convective inhibition and MLCAPE in the 1000-1500 J/kg range will favor high-based thunderstorm development, some of which could be splitting supercells given relatively straight hodographs and effective bulk shear in the 30-35 kt range. The initial/supercells storms will be capable of producing isolated large hail (mainly 1 to 1.75 inches in diameter) and strong/severe outflow gusts. There will be some potential for upscale growth into a small cluster across the South Plains/TX Panhandle tonight as low-level warm advection strengthens, though the severe threat will slowly diminish by late evening. ...Great Basin/Pacific Northwest... Some high-based convection will be possible this afternoon across western UT, around the eastern periphery of the northern CA closed low. Moisture will be limited, but deep inverted-v profiles and minimal buoyancy could support strong outflow winds for a few hours this afternoon/evening. Other isolated strong/elevated storms may occur in the eastern flow regime north of the closed low (along the Cascades), where steep midlevel lapse rates support weak buoyancy. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed May 03 2023 Valid 041200Z - 051200Z ...NO CRITICAL AREAS... The current Day 2 Fire Weather Outlook remains on track with no updates needed. See previous discussion below. ..Thornton.. 05/03/2023 .PREV DISCUSSION... /ISSUED 0137 AM CDT Wed May 03 2023/ ...Synopsis... Fire weather concerns will remain concentrated across the Southwest into parts of the southern High Plains on Thursday. The passage of a sub-tropical shortwave trough over northern Mexico into the southern Plains during the first half of the day will result in somewhat modest lee cyclogenesis across the OK/TX Panhandle region. Regional pressure gradient winds are forecast to increase to 15-20 mph across eastern AZ into much of NM. While the strongest mid-level winds will likely be misphased with peak diurnal warming and the driest fuels, subsidence in the wake of the upper wave should favor a broad swath of 10-20% RH across much of the Southwest. Consequently, elevated fire weather conditions are expected over areas with receptive fuels. Transient critical conditions are possible, but boundary-layer winds between 20-25 mph casts uncertainty onto the duration and coverage of such conditions. Elevated conditions may extend as far northeast as the western TX Panhandle, but this will be dependent on the progression and evolution of the surface low, as well as on fuel status across the Panhandle by Thursday afternoon. Furthermore, elevated conditions are probable across southeast NM and adjacent areas of TX, but ensemble guidance shows a reasonably high (50+%) chance of wetting rainfall over the next 24 hours, which may limit fuel status. Trends will be monitored and adjustments made as the rainfall distribution becomes more apparent. ...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 0255 PM CDT Wed May 03 2023 Valid 041200Z - 051200Z ...NO CRITICAL AREAS... The current Day 2 Fire Weather Outlook remains on track with no updates needed. See previous discussion below. ..Thornton.. 05/03/2023 .PREV DISCUSSION... /ISSUED 0137 AM CDT Wed May 03 2023/ ...Synopsis... Fire weather concerns will remain concentrated across the Southwest into parts of the southern High Plains on Thursday. The passage of a sub-tropical shortwave trough over northern Mexico into the southern Plains during the first half of the day will result in somewhat modest lee cyclogenesis across the OK/TX Panhandle region. Regional pressure gradient winds are forecast to increase to 15-20 mph across eastern AZ into much of NM. While the strongest mid-level winds will likely be misphased with peak diurnal warming and the driest fuels, subsidence in the wake of the upper wave should favor a broad swath of 10-20% RH across much of the Southwest. Consequently, elevated fire weather conditions are expected over areas with receptive fuels. Transient critical conditions are possible, but boundary-layer winds between 20-25 mph casts uncertainty onto the duration and coverage of such conditions. Elevated conditions may extend as far northeast as the western TX Panhandle, but this will be dependent on the progression and evolution of the surface low, as well as on fuel status across the Panhandle by Thursday afternoon. Furthermore, elevated conditions are probable across southeast NM and adjacent areas of TX, but ensemble guidance shows a reasonably high (50+%) chance of wetting rainfall over the next 24 hours, which may limit fuel status. Trends will be monitored and adjustments made as the rainfall distribution becomes more apparent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0671 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF SOUTHEASTERN NM AND WEST TX
Mesoscale Discussion 0671 NWS Storm Prediction Center Norman OK 0252 PM CDT Wed May 03 2023 Areas affected...Portions of southeastern NM and west TX Concerning...Severe potential...Watch possible Valid 031952Z - 032215Z Probability of Watch Issuance...60 percent SUMMARY...The threat for large hail and severe wind gusts should gradually increase as thunderstorms develop this afternoon. Watch issuance is possible. DISCUSSION...Mostly clear/sunny skies have allowed ample daytime heating to occur this afternoon across the southern High Plains. Most locations across southeastern NM into west TX have generally warmed into the upper 70s to mid 80s, amid low to mid 50s surface dewpoints. Although large-scale ascent aloft remains nebulous/weak, convection should continue to gradually develop along the higher terrain of the Sacramento/Guadalupe/Davis Mountains, with modest low-level upslope flow persisting. Once this activity reaches the greater low-level moisture a bit farther east, it should gradually increase in coverage and intensity as it encounters around 1000-2000 J/kg of MLCAPE. Even though low/mid-level winds remain somewhat modest, there is enough veering with height through mid levels to foster 25-35 kt of deep-layer shear. A mix of loosely organized multicells and perhaps a couple of supercells should develop and persist this afternoon and evening. With steep mid-level lapse rates present on the 12Z MAF sounding, any persistent supercell should pose some threat for large hail. Multicell clusters will tend to have more of a severe/damaging wind risk as they spread eastward with time. Primary uncertainty remains the number of thunderstorms that will develop given weak large-scale forcing. Still, if it becomes apparent that multiple robust updrafts will develop/persist, then Severe Thunderstorm Watch issuance will be considered for parts of southeastern NM into west TX. ..Gleason/Thompson.. 05/03/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SJT...LUB...MAF...ABQ... LAT...LON 30950412 32070461 33290455 33620381 33670295 33440223 32970194 31930186 31020186 30030205 29810231 29710259 29600279 29790353 30950412 Read more

MD 0670 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF WESTERN NORTH TX
Mesoscale Discussion 0670 NWS Storm Prediction Center Norman OK 0154 PM CDT Wed May 03 2023 Areas affected...Portions of western north TX Concerning...Severe potential...Watch unlikely Valid 031854Z - 032130Z Probability of Watch Issuance...5 percent SUMMARY...An isolated hail/wind risk may exist with developing thunderstorms this afternoon. Watch issuance is not expected. DISCUSSION...The cu field has recently become agitated along an outflow-reinforced front across western north TX. Latest visible and day cloud phase satellite imagery suggest at least one thunderstorm may develop and persist along this boundary. The low/mid-level flow field remains modest across this region per recent area VWPs, but enough veering/strengthening with height may still support 25-35 kt of deep-layer shear. This should be sufficient for some updraft organization, including marginal supercell potential. If a robust thunderstorm can form and persist, it would tend to move slowly east-southeastward along/near the surface boundary. Around 1000-1500 J/kg of MLCAPE and somewhat steepened mid-level lapse rates should support some threat for isolated large hail. Occasional severe/damaging downdraft winds may also occur as low-level lapse rates continue to steepen. Current expectations are for the severe threat to remain quite isolated, so watch issuance is not currently expected. ..Gleason/Thompson.. 05/03/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...SJT... LAT...LON 32609969 32820000 33229992 33329953 33189863 32779850 32519900 32609969 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1216 PM CDT Wed May 03 2023 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS... ...SUMMARY... Severe thunderstorms capable of large hail, strong/damaging wind gusts, and a couple of tornadoes are possible across parts of the southern Great Plains Thursday afternoon and evening. ...TX/OK/KS... The upper ridge centered over the central/southern Plains will de-amplify on Wednesday as a series of shortwave impulses migrate through west/southwesterly flow. in response to modest height falls, a weak surface low is expected to develop over the western KS vicinity. A dryline will extend southward from the low across western OK into west-central TX. The day will begin with modest boundary-layer moisture across north TX into OK/KS. However, southerly low-level flow will transport a somewhat narrow corridor of low 60s F dewpoints northward across OK/KS through early evening. Deeper boundary-layer moisture will reside further south across central/southern TX where mid/upper 60s F dewpoints are expected. Uncertainty in convective initiation/evolution remains, especially from north TX into KS. A few scenarios are possible, with one point of uncertainty being potentially early ejection of a lead shortwave impulse around midday. If convection develops early in the afternoon, tied to the early shortwave impulse, elevated storms will be more likely. However, some guidance suggests decaying overnight convection and morning cloudiness over OK and vicinity could suppress early CI from the lead shortwave impulse. If this occurs, there may be better potential for late afternoon surface-based convection along the dryline in OK/southern KS. While this leads to a more uncertain/conditional forecast, a moist boundary-layer beneath steep lapse rates will support moderate destabilization. Furthermore, the nose of the midlevel jet will overspread the region during the afternoon and vertically veering profiles will result in 40+ kt effective shear. Supercells will a risk of large hail and strong gusts will be possible. If surface-based afternoon storms develop near the dryline bulge across northwest OK into south-central KS, backed low-level winds and effective SRH increasing to around 250 m2/s2 will support potential for a couple of tornadoes. Further south along the dryline in central TX, strong heating and mid/upper 60s F dewpoints will support MLCAPE values to around 2000-3000 J/kg by afternoon. Low to mid-level flow will be somewhat weak, but rapidly increase with height above 700 mb. Sufficient veering with height also will contribute to effective shear values greater than 40 kt. Supercells capable of large hail (some greater than 2 inches in diameter) will be possible. Given steep low-level lapse rates to around 850 mb and weak low-level winds, strong outflow and storm interactions may support some upward development into forward-propagating clusters by early evening. Damaging gusts in addition to large hail will be possible with this activity. ...Nebraska vicinity... Boundary-layer moisture will remain modest with northward extent into NE. However, steep midlevel lapse rates will support modest destabilization as temperatures warm to near 80 F ahead of a southward-progressing cold front. Modest deep-layer flow will limit longevity/better-organized updrafts, but marginally severe hail and strong gusts will be possible with more intense convection. ...Great Basin/Northwest... Scattered thunderstorms are expected in increasing southwesterly flow on the eastern periphery of the CA/NV upper low, and in the easterly flow regime on the north side of the low across ID toward the Cascades. Limited moisture and a deeply-mixed boundary-layer will result in high-based convection. Steep lapse rates will aid in modest destabilization with gusty winds and small hail possible. ..Leitman.. 05/03/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1216 PM CDT Wed May 03 2023 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS... ...SUMMARY... Severe thunderstorms capable of large hail, strong/damaging wind gusts, and a couple of tornadoes are possible across parts of the southern Great Plains Thursday afternoon and evening. ...TX/OK/KS... The upper ridge centered over the central/southern Plains will de-amplify on Wednesday as a series of shortwave impulses migrate through west/southwesterly flow. in response to modest height falls, a weak surface low is expected to develop over the western KS vicinity. A dryline will extend southward from the low across western OK into west-central TX. The day will begin with modest boundary-layer moisture across north TX into OK/KS. However, southerly low-level flow will transport a somewhat narrow corridor of low 60s F dewpoints northward across OK/KS through early evening. Deeper boundary-layer moisture will reside further south across central/southern TX where mid/upper 60s F dewpoints are expected. Uncertainty in convective initiation/evolution remains, especially from north TX into KS. A few scenarios are possible, with one point of uncertainty being potentially early ejection of a lead shortwave impulse around midday. If convection develops early in the afternoon, tied to the early shortwave impulse, elevated storms will be more likely. However, some guidance suggests decaying overnight convection and morning cloudiness over OK and vicinity could suppress early CI from the lead shortwave impulse. If this occurs, there may be better potential for late afternoon surface-based convection along the dryline in OK/southern KS. While this leads to a more uncertain/conditional forecast, a moist boundary-layer beneath steep lapse rates will support moderate destabilization. Furthermore, the nose of the midlevel jet will overspread the region during the afternoon and vertically veering profiles will result in 40+ kt effective shear. Supercells will a risk of large hail and strong gusts will be possible. If surface-based afternoon storms develop near the dryline bulge across northwest OK into south-central KS, backed low-level winds and effective SRH increasing to around 250 m2/s2 will support potential for a couple of tornadoes. Further south along the dryline in central TX, strong heating and mid/upper 60s F dewpoints will support MLCAPE values to around 2000-3000 J/kg by afternoon. Low to mid-level flow will be somewhat weak, but rapidly increase with height above 700 mb. Sufficient veering with height also will contribute to effective shear values greater than 40 kt. Supercells capable of large hail (some greater than 2 inches in diameter) will be possible. Given steep low-level lapse rates to around 850 mb and weak low-level winds, strong outflow and storm interactions may support some upward development into forward-propagating clusters by early evening. Damaging gusts in addition to large hail will be possible with this activity. ...Nebraska vicinity... Boundary-layer moisture will remain modest with northward extent into NE. However, steep midlevel lapse rates will support modest destabilization as temperatures warm to near 80 F ahead of a southward-progressing cold front. Modest deep-layer flow will limit longevity/better-organized updrafts, but marginally severe hail and strong gusts will be possible with more intense convection. ...Great Basin/Northwest... Scattered thunderstorms are expected in increasing southwesterly flow on the eastern periphery of the CA/NV upper low, and in the easterly flow regime on the north side of the low across ID toward the Cascades. Limited moisture and a deeply-mixed boundary-layer will result in high-based convection. Steep lapse rates will aid in modest destabilization with gusty winds and small hail possible. ..Leitman.. 05/03/2023 Read more

No watches are valid as of Tue May 2 21:32:01 UTC 2023.

MD 0668 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF FAR SOUTHEASTERN NM INTO WEST TX
Mesoscale Discussion 0668 NWS Storm Prediction Center Norman OK 0330 PM CDT Tue May 02 2023 Areas affected...Portions of far southeastern NM into west TX Concerning...Severe potential...Watch possible Valid 022030Z - 022300Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorms may gradually increase in coverage and intensity this afternoon, with both severe winds and hail possible. Trends will be monitored for possible watch issuance. DISCUSSION...Convection has been slowly increasing along and just east of the Sacramento/Guadalupe Mountains in southern NM and the Davis Mountains in west TX. This is occurring as a weak shortwave trough moves over this region, and modest low-level upslope flow continues. The current activity is rather high based, given the presence of generally 30s surface dewpoints and a very well mixed boundary layer where surface heating has occurred. As this convection spreads east-northeastward over the next couple of hours, these thunderstorms will gradually intercept modestly greater low-level moisture characterized by mid 40s to mid 50s surface dewpoints present across far eastern NM into west TX. Some intensification of this convection may occur as it intercepts the greater instability across west TX. Still, deep-layer shear remains rather modest, around 20-30 kt, due to the low-amplitude nature of the shortwave trough and weak low-level mass response. Multicell clusters will probably be the dominant mode with any convection that can persist with eastward extent. Given the steep low/mid-level lapse rates and inverted-v type soundings, severe wind gusts should be the main threat, but some hail may also occur with the more robust updrafts. Overall convective organization and intensity may remain somewhat marginal/isolated late this afternoon and evening, and the need for a watch is unclear. Regardless, observational trends will be closely monitored. ..Gleason/Thompson.. 05/02/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LUB...MAF...ABQ... LAT...LON 31300293 31580328 32020350 33770349 34260324 34350275 34330219 34090186 33710174 33110166 32060169 31480212 31280249 31300293 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Tue May 02 2023 Valid 031200Z - 041200Z The current Day 2 Fire Weather Outlook is on track with no changes needed. See previous discussion below. ..Thornton.. 05/02/2023 .PREV DISCUSSION... /ISSUED 0216 AM CDT Tue May 02 2023/ ...Synopsis... Fire weather concerns will primarily be focused across the Southwest on Wednesday. A sub-tropical shortwave trough is forecast to migrate out of northern Mexico into the Southwest through the day. This will lead to broad, but modest, pressure falls across the Four Corners and southern High Plains. In response, southerly winds are forecast to increase to 15-20 mph from the international border into the Four Corners and eastern Great Basin. Downslope warming and drying will support areas of 15-20% RH coincident with breezy winds. Elevated fire weather conditions are possible across much of the region, but the fire concern will be focused primarily across southeast AZ into southwest and central NM where ERCs have reached the 80-90th percentile amid a prolonged (30-day) period of negligible rainfall. ...Georgia into South Carolina... Another day of dry and breezy weather is expected as a Great Lakes low continues to meander northeast. Gradient winds will likely be weaker compared to today (Tuesday), but most solutions hint at winds near 15 mph during peak heating when RH values will likely be around 25-30%. Elevated fire weather conditions are possible, but the overall fire threat will be conditional on fuel status by Wednesday afternoon. Widespread drying/curing of fine fuels is expected today, and may be sufficient for highlights in subsequent 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 0255 PM CDT Tue May 02 2023 Valid 031200Z - 041200Z The current Day 2 Fire Weather Outlook is on track with no changes needed. See previous discussion below. ..Thornton.. 05/02/2023 .PREV DISCUSSION... /ISSUED 0216 AM CDT Tue May 02 2023/ ...Synopsis... Fire weather concerns will primarily be focused across the Southwest on Wednesday. A sub-tropical shortwave trough is forecast to migrate out of northern Mexico into the Southwest through the day. This will lead to broad, but modest, pressure falls across the Four Corners and southern High Plains. In response, southerly winds are forecast to increase to 15-20 mph from the international border into the Four Corners and eastern Great Basin. Downslope warming and drying will support areas of 15-20% RH coincident with breezy winds. Elevated fire weather conditions are possible across much of the region, but the fire concern will be focused primarily across southeast AZ into southwest and central NM where ERCs have reached the 80-90th percentile amid a prolonged (30-day) period of negligible rainfall. ...Georgia into South Carolina... Another day of dry and breezy weather is expected as a Great Lakes low continues to meander northeast. Gradient winds will likely be weaker compared to today (Tuesday), but most solutions hint at winds near 15 mph during peak heating when RH values will likely be around 25-30%. Elevated fire weather conditions are possible, but the overall fire threat will be conditional on fuel status by Wednesday afternoon. Widespread drying/curing of fine fuels is expected today, and may be sufficient for highlights in subsequent updates. ...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 0238 PM CDT Tue May 02 2023 Valid 022000Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST NEW MEXICO AND WEST-CENTRAL TEXAS... ...SUMMARY... A few severe thunderstorm gusts and isolated large hail will be possible through evening across eastern New Mexico and west Texas. ...Southern High Plains... Aside from minor changes to the 10 percent general thunder line, no changes have been made to the ongoing outlook with the 20z update. Isolated thunderstorms are developing near the higher terrain of southwest TX into southern NM as of 1930z. This activity is developing within a drier, weakly unstable airmass. However, as convection shifts east toward modestly better moisture/instability, increasing potential for severe wind/hail is expected through evening. ..Leitman.. 05/02/2023 .PREV DISCUSSION... /ISSUED 1127 AM CDT Tue May 02 2023/ ...Southern High Plains this afternoon/evening... The persistent omega block persists over the CONUS, with a deep low over the Great Lakes/Northeast, a ridge over the Rockies, and another midlevel low over northern CA. A plume of midlevel moisture extends from the northern CA low southeastward toward west TX, within the deformation zone between the two deep lows. Subtle speed maxima are moving northeastward from northern Mexico toward the southern High Plains, as low-level moisture gradually increases from the southeast (in response to weak lee troughing). In the immediate wake of morning clouds, strong surface heating and modest increases in low-level moisture will contribute to destabilization this afternoon, when MLCAPE will approach 1000 J/kg. The 12z MAF/EPZ soundings suggest that the warmest elevated mixed layer plume is already over TX, with cooler upstream temperatures. Thus, afternoon surface temperatures into the mid 80s should be sufficient to mix through the base of the elevated mixed layer, reducing convective inhibition and supporting scattered thunderstorm development across eastern NM/west TX along the lee trough. The weak-moderate buoyancy and steep lapse rate profiles, in combination with rather modest deep-layer shear and relatively straight hodographs, will support a mix of multicell clusters and perhaps some splitting supercells. The primary severe threat will be a few severe outflow gusts with the high-based storms, though isolated/marginally severe hail may occur with transient supercell structures and/or favorable storm mergers/interactions. The severe-weather threat will peak late afternoon and slowly diminish by late evening, though slightly elevated storms could persist overnight. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Tue May 02 2023 Valid 022000Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST NEW MEXICO AND WEST-CENTRAL TEXAS... ...SUMMARY... A few severe thunderstorm gusts and isolated large hail will be possible through evening across eastern New Mexico and west Texas. ...Southern High Plains... Aside from minor changes to the 10 percent general thunder line, no changes have been made to the ongoing outlook with the 20z update. Isolated thunderstorms are developing near the higher terrain of southwest TX into southern NM as of 1930z. This activity is developing within a drier, weakly unstable airmass. However, as convection shifts east toward modestly better moisture/instability, increasing potential for severe wind/hail is expected through evening. ..Leitman.. 05/02/2023 .PREV DISCUSSION... /ISSUED 1127 AM CDT Tue May 02 2023/ ...Southern High Plains this afternoon/evening... The persistent omega block persists over the CONUS, with a deep low over the Great Lakes/Northeast, a ridge over the Rockies, and another midlevel low over northern CA. A plume of midlevel moisture extends from the northern CA low southeastward toward west TX, within the deformation zone between the two deep lows. Subtle speed maxima are moving northeastward from northern Mexico toward the southern High Plains, as low-level moisture gradually increases from the southeast (in response to weak lee troughing). In the immediate wake of morning clouds, strong surface heating and modest increases in low-level moisture will contribute to destabilization this afternoon, when MLCAPE will approach 1000 J/kg. The 12z MAF/EPZ soundings suggest that the warmest elevated mixed layer plume is already over TX, with cooler upstream temperatures. Thus, afternoon surface temperatures into the mid 80s should be sufficient to mix through the base of the elevated mixed layer, reducing convective inhibition and supporting scattered thunderstorm development across eastern NM/west TX along the lee trough. The weak-moderate buoyancy and steep lapse rate profiles, in combination with rather modest deep-layer shear and relatively straight hodographs, will support a mix of multicell clusters and perhaps some splitting supercells. The primary severe threat will be a few severe outflow gusts with the high-based storms, though isolated/marginally severe hail may occur with transient supercell structures and/or favorable storm mergers/interactions. The severe-weather threat will peak late afternoon and slowly diminish by late evening, though slightly elevated storms could persist overnight. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Tue May 02 2023 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST TEXAS TO FAR EASTERN COLORADO AND WESTERN KANSAS... ...SUMMARY... Isolated to widely scattered strong to severe thunderstorms capable of strong gusts and large hail are possible Wednesday afternoon and evening across the central and southern High Plains. ...Southern/Central High Plains... An upper ridge will be centered over the Rockies and adjacent High Plains on Wednesday. Various weak impulses related to remnants of Day 1/Tuesday convection will be shifting east across KS/OK early in the period. Thereafter, forcing for ascent will remain nebulous until late in the period when a shortwave impulse is forecast to eject into the southern Rockies/High Plains vicinity after 03z. This later impulse will be ill-timed for diurnal convection. Modest boundary-layer moisture (surface dewpoints from the mid 50s to low 60s F) is forecast from southwest TX northward through the OK/TX Panhandles and into far eastern CO/western KS. Steep midlevel lapse rates will contribute to MLCAPE values around 1500-2000 J/kg, with much of the instability focused above 700 mb atop a weak EML. Deep-layer flow also will remain fairly weak beneath the upper ridge, though favorable veering with height will be sufficient for effective shear values near 30 kt. Strong heating and low-level convergence should be sufficient to support isolated thunderstorm development by afternoon. Shear will be marginally favorable for transient supercells and clusters. Elongated hodographs above 2-3 km coupled with favorable thermodynamic profiles suggest large hail will be possible with any sustained semi-discrete convection. Steep low-level lapse rates also may support isolated strong downburst winds. Modestly enlarged low-level hodographs and around 100 J/kg 0-3km MLCAPE typically would indicate some potential for a tornado. However, given modest boundary-layer moisture and weak 0-1 km shear, the tornado threat is expected to remain minimal. ...Oregon/Washington... Modest heating/destabilization will again support thunderstorm development across parts of the interior Northwest on Wednesday. Guidance still suggests that a midlevel shortwave trough embedded within the broader cyclonic flow may be favorably timed for storm development during the late afternoon/evening across western/northern OR into southern WA. Some uncertainty regarding low-level moisture, and hence degree of destabilization, is evident in forecast surface dewpoints. The operational NAM remains more aggressive with boundary-layer dewpoints compared to most other guidance. While some low severe potential may develop (mainly for hail), current expectation is for a few strong storms capable of mainly small, sub-severe hail. ..Leitman.. 05/02/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Tue May 02 2023 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST TEXAS TO FAR EASTERN COLORADO AND WESTERN KANSAS... ...SUMMARY... Isolated to widely scattered strong to severe thunderstorms capable of strong gusts and large hail are possible Wednesday afternoon and evening across the central and southern High Plains. ...Southern/Central High Plains... An upper ridge will be centered over the Rockies and adjacent High Plains on Wednesday. Various weak impulses related to remnants of Day 1/Tuesday convection will be shifting east across KS/OK early in the period. Thereafter, forcing for ascent will remain nebulous until late in the period when a shortwave impulse is forecast to eject into the southern Rockies/High Plains vicinity after 03z. This later impulse will be ill-timed for diurnal convection. Modest boundary-layer moisture (surface dewpoints from the mid 50s to low 60s F) is forecast from southwest TX northward through the OK/TX Panhandles and into far eastern CO/western KS. Steep midlevel lapse rates will contribute to MLCAPE values around 1500-2000 J/kg, with much of the instability focused above 700 mb atop a weak EML. Deep-layer flow also will remain fairly weak beneath the upper ridge, though favorable veering with height will be sufficient for effective shear values near 30 kt. Strong heating and low-level convergence should be sufficient to support isolated thunderstorm development by afternoon. Shear will be marginally favorable for transient supercells and clusters. Elongated hodographs above 2-3 km coupled with favorable thermodynamic profiles suggest large hail will be possible with any sustained semi-discrete convection. Steep low-level lapse rates also may support isolated strong downburst winds. Modestly enlarged low-level hodographs and around 100 J/kg 0-3km MLCAPE typically would indicate some potential for a tornado. However, given modest boundary-layer moisture and weak 0-1 km shear, the tornado threat is expected to remain minimal. ...Oregon/Washington... Modest heating/destabilization will again support thunderstorm development across parts of the interior Northwest on Wednesday. Guidance still suggests that a midlevel shortwave trough embedded within the broader cyclonic flow may be favorably timed for storm development during the late afternoon/evening across western/northern OR into southern WA. Some uncertainty regarding low-level moisture, and hence degree of destabilization, is evident in forecast surface dewpoints. The operational NAM remains more aggressive with boundary-layer dewpoints compared to most other guidance. While some low severe potential may develop (mainly for hail), current expectation is for a few strong storms capable of mainly small, sub-severe hail. ..Leitman.. 05/02/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Tue May 02 2023 Valid 021700Z - 031200Z No changes are needed to the current Day 1 Fire Weather Outlook. See previous discussion below. ..Thornton.. 05/02/2023 .PREV DISCUSSION... /ISSUED 0141 AM CDT Tue May 02 2023/ ...Synopsis... ...Minnesota to Iowa... Elevated fire weather concerns are expected this afternoon across parts of Minnesota into northern Iowa. Early-morning satellite and surface observations continue to show a stacked upper and surface low over the lower Great Lakes region. This system will continue to gradually shift east today, but will maintain breezy northerly gradient winds across the upper MS Valley. Previous 24-hour observations across MN show a slight drying trend with dewpoints falling into the low to mid 20s. Recent model solutions have had a slight moist-bias during this period, and continue the slow drying trend into this afternoon. Consequently, afternoon RH values will likely fall below yesterday's observed RH minimums. Gradient winds between 15-25 mph are expected with frequent gusts up to 35 mph. Little rainfall over the past week, coupled with curing from hot, dry, windy conditions yesterday, has allowed ERCs to approach the 90th percentile for some locations. Refinements to the risk area have been made across IA to reflect where local fuel reports indicate spring green up has sufficiently mitigated fuel receptiveness. ...Southeast NM into southwest TX... 00 UTC soundings from MAF and EPZ show steep mid-level lapse rates with dry, well-mixed boundary layers and PWAT values near 0.5 inch. This thermodynamic profile is expected to largely remain in place through the afternoon as ascent associated with an sub-tropical shortwave trough overspreads the region. A few isolated dry thunderstorms are possible over the region where ERC values are in excess of the 80th percentile. Additional thunderstorms are expected in the periphery of the risk area, but latest ensemble guidance suggests the probability of wetting rainfall is higher. ...Georgia into South Carolina... Westerly gradient winds on the southern periphery of the Great Lakes low are forecast to be sustained around 15 mph (gusting to 20-30 mph) from GA eastward to the Carolina coast. A dry continental air mass moving into the region, coupled with diurnal warming, will support RH reductions into the 20-30% range. Elevated to locally critical fire weather conditions appear probable, but widespread rainfall amounts of 0.25-0.5 inch over the past 48-72 hours cast uncertainty onto the coverage of receptive fuels. As such, the fire concern will primarily be focused on local areas where dead grasses and other fine fuels have sufficiently dried over the past 24-48 hours. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Tue May 02 2023 Valid 021700Z - 031200Z No changes are needed to the current Day 1 Fire Weather Outlook. See previous discussion below. ..Thornton.. 05/02/2023 .PREV DISCUSSION... /ISSUED 0141 AM CDT Tue May 02 2023/ ...Synopsis... ...Minnesota to Iowa... Elevated fire weather concerns are expected this afternoon across parts of Minnesota into northern Iowa. Early-morning satellite and surface observations continue to show a stacked upper and surface low over the lower Great Lakes region. This system will continue to gradually shift east today, but will maintain breezy northerly gradient winds across the upper MS Valley. Previous 24-hour observations across MN show a slight drying trend with dewpoints falling into the low to mid 20s. Recent model solutions have had a slight moist-bias during this period, and continue the slow drying trend into this afternoon. Consequently, afternoon RH values will likely fall below yesterday's observed RH minimums. Gradient winds between 15-25 mph are expected with frequent gusts up to 35 mph. Little rainfall over the past week, coupled with curing from hot, dry, windy conditions yesterday, has allowed ERCs to approach the 90th percentile for some locations. Refinements to the risk area have been made across IA to reflect where local fuel reports indicate spring green up has sufficiently mitigated fuel receptiveness. ...Southeast NM into southwest TX... 00 UTC soundings from MAF and EPZ show steep mid-level lapse rates with dry, well-mixed boundary layers and PWAT values near 0.5 inch. This thermodynamic profile is expected to largely remain in place through the afternoon as ascent associated with an sub-tropical shortwave trough overspreads the region. A few isolated dry thunderstorms are possible over the region where ERC values are in excess of the 80th percentile. Additional thunderstorms are expected in the periphery of the risk area, but latest ensemble guidance suggests the probability of wetting rainfall is higher. ...Georgia into South Carolina... Westerly gradient winds on the southern periphery of the Great Lakes low are forecast to be sustained around 15 mph (gusting to 20-30 mph) from GA eastward to the Carolina coast. A dry continental air mass moving into the region, coupled with diurnal warming, will support RH reductions into the 20-30% range. Elevated to locally critical fire weather conditions appear probable, but widespread rainfall amounts of 0.25-0.5 inch over the past 48-72 hours cast uncertainty onto the coverage of receptive fuels. As such, the fire concern will primarily be focused on local areas where dead grasses and other fine fuels have sufficiently dried over the past 24-48 hours. ...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 1127 AM CDT Tue May 02 2023 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR WEST CENTRAL TX AND SOUTHEAST NM... ...SUMMARY... A few severe thunderstorm gusts and isolated large hail will be possible this afternoon/evening across eastern New Mexico and west Texas. ...Southern High Plains this afternoon/evening... The persistent omega block persists over the CONUS, with a deep low over the Great Lakes/Northeast, a ridge over the Rockies, and another midlevel low over northern CA. A plume of midlevel moisture extends from the northern CA low southeastward toward west TX, within the deformation zone between the two deep lows. Subtle speed maxima are moving northeastward from northern Mexico toward the southern High Plains, as low-level moisture gradually increases from the southeast (in response to weak lee troughing). In the immediate wake of morning clouds, strong surface heating and modest increases in low-level moisture will contribute to destabilization this afternoon, when MLCAPE will approach 1000 J/kg. The 12z MAF/EPZ soundings suggest that the warmest elevated mixed layer plume is already over TX, with cooler upstream temperatures. Thus, afternoon surface temperatures into the mid 80s should be sufficient to mix through the base of the elevated mixed layer, reducing convective inhibition and supporting scattered thunderstorm development across eastern NM/west TX along the lee trough. The weak-moderate buoyancy and steep lapse rate profiles, in combination with rather modest deep-layer shear and relatively straight hodographs, will support a mix of multicell clusters and perhaps some splitting supercells. The primary severe threat will be a few severe outflow gusts with the high-based storms, though isolated/marginally severe hail may occur with transient supercell structures and/or favorable storm mergers/interactions. The severe-weather threat will peak late afternoon and slowly diminish by late evening, though slightly elevated storms could persist overnight. ..Thompson/Squitieri.. 05/02/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Mon May 01 2023 Valid 021200Z - 031200Z ...NO CRITICAL AREAS... The current Elevated region across southwest MN and portions of IA within the D2 Fire Weather Outlook remains on track with no updates needed. See previous discussion below for more information. ...Dry Thunderstorms... A mix of dry and wet scattered thunderstorms will be possible across southeastern New Mexico. Gradual moistening is expected through the afternoon, with afternoon relative humidity approaching 30-40 percent. This, in combination with slower storm motions around 15 mph, will allow for measurable precipitation chances to increase through the afternoon. Relative humidity around 20 percent will be most likely across southeastern New Mexico in the early afternoon as thunderstorms develop with very dry sub-cloud conditions. A period of isolated dry thunderstorms will be possible within this region. ERCs in this region are approaching the 90th percentile. As such, this region has been included in isolated dry thunder. ..Thornton.. 05/01/2023 .PREV DISCUSSION... /ISSUED 1253 AM CDT Mon May 01 2023/ ...Synopsis... Elevated fire weather conditions are expected Tuesday afternoon across southwest MN into parts of IA. North/northwesterly gradient winds are expected to linger across the region into Tuesday, and the persistent northerly flow will usher in a dry air mass from the Canadian Prairies. Ensemble and deterministic guidance shows a reasonable signal for 15-25% RH across this region with sustained winds between 15-20 mph. Although the axis of stronger mid-level winds will shift east through the day, gusts up to 25-30 mph will be possible. Fine grasses across the region are expected to undergo curing today (Monday) given the warm, dry, and windy forecast, which should support the fire weather concern on Tuesday. Across the Southwest and Great Basin, another day of breezy southerly winds is expected, but an influx of moisture from the Gulf of California should limit RH reductions compared to today/Monday. Consequently, only localized fire weather concerns are anticipated, mainly across southern AZ to southwest NM where fuels are driest. ...Please see www.spc.noaa.gov/fire for graphic product... Read more