Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Wed Apr 19 2023 Valid 201200Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE MIDDLE MISSISSIPPI VALLEY INTO THE ARKLATEX AND CENTRAL TEXAS... ...SUMMARY... Widely scattered severe thunderstorms capable of hail and severe gusts are possible from parts of mid Mississippi Valley southwestward into the Ark-La-Tex and central Texas Thursday afternoon and Thursday night. ...Synopsis... A mid-level low will migrate slowly eastward across the Upper Midwest with a larger-scale trough longitudinally located over the Great Plains. An embedded disturbance/mid-level speed max will quickly move from KS/NE Thursday morning to WI by early evening. In the low levels, a surface low will develop northeastward from IA into the Upper Great Lakes and occlude, while a trailing cold front will push east/southeast across the mid MS Valley into the southern Great Plains. ...Ozarks/Ark-La-Tex/Southern Plains... A cold front will bisect OK and extend north-northeastward into eastern KS/western MO during the morning and continue east-southeast through peak heating. A reservoir of adequately rich low-level moisture --characterized by mid-upper 60s dewpoints-- will reside across the Ozarks southward into north TX. Strong heating will contribute to a moderate to very unstable airmass by early-mid afternoon. MLCAPE is forecast to range from near 1000 J/kg over southern MO to 3500 J/kg over central TX. As the cap weakens near the front during peak heating, scattered thunderstorms are forecast to develop. Moderate to strong deep-layer shear will promote storm organization. Supercells capable of large to very large hail will be possible from north TX southward along the I-35 corridor into central TX. Additional storm development is likely during the evening with upscale growth in one or more bands of storms likely during the evening into the overnight. The severe risk will likely lessen as storms move east nearing the MS River and moving towards the Gulf Coast late. ...Mid MS Valley and WI... At the start of the Day-2 period, a 60-kt LLJ will be located over the lower MO Valley. This feature's associated warm-air advection will promote scattered showers/thunderstorms during the morning across northern MO into the eastern half of IA and parts of adjacent IL/WI during the morning. Elevated buoyancy amidst strong shear will lend a conditional risk for strong and locally severe thunderstorms. Isolated large hail and perhaps damaging gusts may accompany this activity. It remains a bit uncertain whether this early day thunderstorm activity will continue and/or additional storms will redevelop via cloud breaks/heating during the midday into the afternoon, especially with north extent. Nonetheless, it seems a severe risk may develop during the afternoon and perhaps linger into the evening with a broken band of storms from the mid MS Valley northward into WI. If greater destabilization can occur from IL into southern WI, a focused threat for damaging gusts and perhaps a tornado or two could materialize Thursday afternoon/early evening. Uncertainty is high regarding this scenario and will defer this possibility to later outlooks. ..Smith.. 04/19/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Wed Apr 19 2023 Valid 191700Z - 201200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NEW MEXICO ONTO THE SOUTHERN HIGH PLAINS.... ...Southern Plains... Minor adjustments have been made to the northern end of the Elevated and Critical areas across southern KS. The northward limit of critical fire-weather conditions is uncertain today given the cold front has progressed slightly farther south than previous guidance. Otherwise, the forecast remains unchanged. ...Mid Atlantic... Strong mid-level flow lingering over the eastern US may support a few hours of breezy winds across portions of NJ and southern NY State. RH values are expected to be only marginally supportive given cooler temperatures in the post-frontal air mass. However, with winds near 15 mph, at least a few hours of locally elevated fire-weather conditions may develop within areas of moderately receptive fuels. ..Lyons.. 04/19/2023 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Apr 19 2023/ ...Synopsis... A mid-level trough will overspread the central U.S. today, resulting in surface low development and the eastward surge of a dryline during the afternoon. Widespread dry and windy conditions are expected in the post-dryline environment, with Critical highlights maintained where 20+ mph sustained westerly surface winds will overlap with 10-20 percent RH and dry fuels for several hours. Dry and windy conditions are also expected immediately behind the cold front across western into central Nebraska, where Elevated highlights remain. Here, dry downslope flow will contribute to overlapping 15 mph sustained northwesterly winds and 15-20 percent RH by afternoon peak heating. Elevated highlights have been adjusted where the aforementioned Elevated meteorological surface conditions coincide with dry fuels that have not experienced recent rainfall. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1139 AM CDT Wed Apr 19 2023 Valid 191630Z - 201200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MID-MO VALLEY... CORRECTED FOR HAIL AND CATEGORICAL LINES IN IL ...SUMMARY... Multiple rounds of scattered severe thunderstorms are expected from late afternoon into tonight across the Mid-Missouri Valley. Very large hail is likely, and significant severe wind gusts along with a few tornadoes will be possible. A conditional threat for isolated significant severe storms also exists farther south into western/central Oklahoma and western north Texas this evening. ...Mid-MO Valley... Three rounds of severe potential appear increasingly evident across the Mid-MO Valley vicinity beginning in the late afternoon and continuing tonight. The first should consist of elevated thunderstorms north of the slow-moving/quasi-stationary warm front that is arcing east of the initial primary surface cyclone over southeast NE. This activity near the NE/SD/IA border will probably evolve into a couple of elevated supercells within an eastward-moving cluster, owing to favorable cloud-bearing shear along the northern gradient of the peak buoyancy plume across the central Great Plains. Large hail will be the primary hazard. A separate area of dryline to warm-sector storm development is anticipated towards the KS/NE/MO/IA border during the early evening in the exit region of a strengthening low-level jet in OK/KS/MO. This ascent combined with the boundary-layer thermal ridge from western OK to central/eastern KS should be enough to overcome the pronounced elevated mixed-layer across the Great Plains. 12Z NAM guidance remains terribly inconsistent with the 00Z ECMWF, recent RAP guidance, and comparison to surface observations. It is already much too cool with current temperatures with it's typical too cool/moist boundary layer. It appears more likely that a relatively well-mixed boundary layer within this portion of the warm/moist sector will be characterized by surface dew points from 58-61 F as storms form. This will seemingly support a mix of large hail, damaging wind gusts, and a couple tornadoes with supercells that initially form. Given a relatively confined buoyancy plume, regenerative convection is likely through the evening, yielding a broadening cluster with embedded supercell structures. Tonight, a third round of severe storms should develop near the south-central NE/north-central KS border. This should occur as a lee cyclone over the central High Plains shifts east, in association with a shortwave impulse progressing through the basal portion of the broader mid-level trough over the West. A surge of low-level moisture northwestward amid an intense 60-70 kt low-level jet should support emerging elevated supercell clusters that track east overnight, potentially merging with lingering convection downstream. Severe wind gusts and large hail will be the primary threats. ...Western/central OK into western north TX... Storm development is uncertain along the dryline during the late afternoon to early evening, given little in the way of height falls/forcing for ascent, and the presence of a substantial warm-sector cap. Storm initiation will rely on the depth of mixing with surface heating along the dryline, and on parcel residence time in the dryline zone of ascent. Flow in the 850-700 mb layer will be a bit more parallel to the dryline compared to yesterday, which may allow long enough residence times to reach an LFC. If storms form, the environment favors a threat of isolated very large hail with any sustained supercell. During the evening, substantial intensification of the low-level jet and an increase in boundary-layer moisture renders concern for a conditional strong tornado threat after dusk. Overall moisture appears a bit less compared to past nocturnal intense tornado events and confidence is low in whether a supercell or two can become established prior to increasing MLCIN during the late evening. As such, confidence in occurrence/coverage is low, but intensity is conditionally significant. ..Grams/Thornton.. 04/19/2023 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Tue Apr 18 2023 Valid 182000Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE CENTRAL STATES... ...SUMMARY... Isolated severe thunderstorms are possible from parts of the southern Great Plains northward into the Mid Missouri Valley/Upper Midwest and westward into Wyoming. Large hail and severe wind gusts will be the hazards with the stronger storms late this afternoon into tonight. ...Discussion... No change is warranted to the previous convective outlook. ..Smith.. 04/18/2023 .PREV DISCUSSION... /ISSUED 1126 AM CDT Tue Apr 18 2023/ ...Central/southern Great Plains to Mid-MO Valley/Upper Midwest... Modified moisture return is occurring from the southern Great Plains ahead of a deepening lee cyclone over the central High Plains. But guidance has above-average spread in the degree of this return into KS and southern NE by early evening, lowering confidence in the overall environment and sustenance of deep convection given the stout elevated mixed-layer over the moist sector. Based on 12Z observed soundings, GOES PW imagery, and 16Z surface observations, it appears that the drier spectrum of guidance is more reasonable with the magnitude of this return, suggesting mid 40s to mid 50s surface dew points north of OK by 00Z. This should be adequate to support isolated high-based thunderstorms along the dryline in the western KS vicinity during the late afternoon to early evening. This activity will pose a threat for isolated large hail and localized severe wind gusts. Still, morning HRRR runs are insistent that even this scenario will fail, with effectively no sustained deep convection along the entire dryline. During the evening, a strengthening low-level jet will yield warm theta-e advection tonight. This might support any lingering dryline storms spreading northeast towards the Mid-MO Valley or more likely the development of elevated thunderstorms where ascent can overcome the stout elevated mixed-layer. Steep mid-level lapse rates and favorable cloud-layer shear will conditionally support a few elevated supercells, although the predominant convective mode should tend towards clusters northeast of the surface warm front. Isolated large hail appears to be the main threat. ...WY to western SD/NE... An elongated upper trough over the Northwest should consolidate across the northern Great Plains tonight. This will occur as a piece of the strong mid-level jet across northern/central CA and the Sierras ejects across the central Rockies to the Black Hills vicinity. This strengthening flow regime and large-scale ascent will aid in scattered high-based, low-topped convection across WY this afternoon and spreading into western SD/NE this evening. With surface dew points only in the 20s to low 30s, buoyancy will likely remain scant. But inverted-v thermodynamic profiles will support a threat for sporadic severe wind gusts. Read more

No watches are valid as of Tue Apr 18 19:46:02 UTC 2023.

No Mesoscale Discussions are in effect as of Tue Apr 18 19:46:02 UTC 2023.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0150 PM CDT Tue Apr 18 2023 Valid 191200Z - 201200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN HIGH PLAINS AND CENTRAL/EASTERN NEW MEXICO... The previous outlook remains valid with no major changes. See the prior discussion. ..Lyons.. 04/18/2023 .PREV DISCUSSION... /ISSUED 0120 AM CDT Tue Apr 18 2023/ ...Synopsis... A mid-level trough will eject into the Plains tomorrow/Wednesday, with surface lee troughing expected across the northern Plains, and surface low development across the southern Plains. Across the southern Plains, a dryline will rapidly advance eastward across western Oklahoma and Kansas, with widespread dry and windy conditions expected across the southern High Plains. Critical highlights have been added across much of New Mexico into far southeast Colorado into the Oklahoma and Texas Panhandles, where widespread 20 mph sustained westerly winds will overlap with 10-20 percent RH and dry fuels. Elevated highlights have also been introduced farther north across western into central Nebraska, where overlapping 15-20 percent RH and 15+ mph sustained northwesterly surface winds will occur behind a passing surface cold front. While portions of Nebraska may experience thunderstorms before the cold front moves through, these storms are expected to be isolated. As such, widespread appreciable rainfall accumulations appear unlikely, and fuels are expected to be receptive enough to support wildfire spread. ...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 1229 PM CDT Tue Apr 18 2023 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF WESTERN OKLAHOMA AND INTO CENTRAL KANSAS AND INTO CENTRAL IOWA... ...SUMMARY... Severe thunderstorms with the potential for giant hail, a risk for a couple of tornadoes, and severe gusts will be possible late Wednesday afternoon into Wednesday night across parts of the central states. ...Central Great Plains into the mid-upper MS Valley... A stationary mid-level low over western ND and associated larger-scale trough over the Interior West, will result in a belt of strengthening southwesterly mid- to high-level flow across the central-southern Great Plains into parts of the Corn Belt. A surface low initially over ND will occlude and weaken while another surface low develops over the KS during the day. A frontal zone will extend from the northern low southward to near the IA/NE border and to the low over KS. A dryline will extend southward from central KS through western OK and west-central TX. Southerly low-level flow will advect moisture northward from the TX/OK into KS and eastern NE with surface dewpoints forecast to reach the upper 50s to near 60 deg F over western IA to the lower-mid 60s over central KS/western OK. Strong diurnal heating is forecast over the Great Plains in the warm sector ahead of a 70-kt 500-mb speed max forecast to move into KS during the overnight. Of particular note, a low-level thermal ridge is forecast to extend from the TX Panhandle northeastward into central KS abutting the dryline near the I-135 corridor. It is on the northeast periphery of the steep 0-3-km lapse rates and beneath the left exit region of the upper jet that convective initiation is most probable during the late afternoon/early evening. Forecast soundings show a moderate to very unstable boundary layer (MLCAPE ranging from 2000 J/kg near the IA/NE border to 3000 J/kg near the dryline). As the cap weakens by mid-late afternoon, widely spaced CI attempts will likely become evident. It seems plausible isolated storms will eventually develop near/northeast of the triple point with the potential for rapid supercell development. Forecast hodographs enlarge in the lowest 2-km AGL layer during the 22z-01z period, and in addition to risk for very large hail, a tornado threat may also develop. Storm coverage is expected to increase during the evening as the LLJ intensifies and into the overnight and perhaps preferentially develop along the front while growing upscale and moving east into the lower MO Valley late. A lingering hail/wind risk will probably accompany this activity. Farther south along the dryline over south-central KS to near the Red River, the leading edge of strong, westerly 80-90 kt 200-mb flow will overspread the warm sector by late afternoon, thereby elongating the hodograph. Very strong heating may lead to local erosion of the cap with one or a few updrafts becoming sustained and quickly evolving to a discrete supercell mode. A conditionally very favorable environment over OK for a giant-hail risk (diameters 3+ inches) may develop with any supercell. As this activity matures during the early evening, increasing CINH with east extent and with the onset of diurnal cooling will combine to limit the tornado risk before CINH eventually overwhelms lingering updrafts and coincides to a dissipation of the storm activity by mid evening. ...TX dryline... Model guidance currently indicates a paucity of convective potential along the dryline over parts of northwest TX southward to the Edwards Plateau. A conditionally very unstable boundary layer and deep-layer shear will support supercell potential. Any storm that manages to develop will likely pose a large-hail threat for at least an hour or two before this risk diminishes by mid evening. ..Smith.. 04/18/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Tue Apr 18 2023 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR MUCH OF NEW MEXICO AND THE SOUTHERN/CENTRAL HIGH PLAINS... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF CENTRAL AND EASTERN VIRGINIA... ...Mid Atlantic... Early morning observations show clear skies and surface temperatures quickly warming into the 60s and 70s F over much of DelMarVa into southern NJ. Dry surface conditions with RH values in the low 20s were being observed along with westerly surface winds near 20 mph. Current trends lend higher confidence in widespread elevated and critical conditions developing this afternoon over mostly receptive fuels. Fire-weather concerns will likely continue into this early evening before wind slacken and humidity recovers. Otherwise, the previous forecast remains valid with no changes. ..Lyons.. 04/18/2023 .PREV DISCUSSION... /ISSUED 0116 AM CDT Tue Apr 18 2023/ ...Synopsis... A mid-level trough will approach the Plains while a second trough ejects into the Atlantic today. Surface low development is likely across the central High Plains, with a dryline poised to advance eastward across western Kansas into the Texas Panhandle. Behind the dryline, 20+ mph sustained westerly surface winds amid 15 percent RH will promote widespread Critical conditions from central New Mexico/Colorado into southwest Kansas and the Oklahoma/Texas Panhandles. Along/immediately ahead of the dryline, an isolated thunderstorm or two may develop from southwestern Kansas into northwestern Texas. Given relatively low confidence in thunderstorm initiation, isolated dry thunderstorm highlights have been withheld this outlook. Nonetheless, any storms that can develop should be high-based, and a couple of dry strikes are possible immediately after initiation before storms can mature. Across the Mid Atlantic, a corridor of dry westerly surface winds appear likely this afternoon from eastern West Virginia to the Atlantic Seaboard given the passage of a surface lee trough. Elevated highlights have been added where surface wind speeds are expected to reach 15 mph amid 20-30 percent RH for at least a few hours, and where fuels are dry enough to support wildfire-spread. ...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 1126 AM CDT Tue Apr 18 2023 Valid 181630Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE CENTRAL STATES... ...SUMMARY... Isolated severe thunderstorms are possible from parts of the southern Great Plains northward into the Mid Missouri Valley/Upper Midwest and westward into Wyoming. Large hail and severe wind gusts will be the hazards with the stronger storms late this afternoon into tonight. ...Central/southern Great Plains to Mid-MO Valley/Upper Midwest... Modified moisture return is occurring from the southern Great Plains ahead of a deepening lee cyclone over the central High Plains. But guidance has above-average spread in the degree of this return into KS and southern NE by early evening, lowering confidence in the overall environment and sustenance of deep convection given the stout elevated mixed-layer over the moist sector. Based on 12Z observed soundings, GOES PW imagery, and 16Z surface observations, it appears that the drier spectrum of guidance is more reasonable with the magnitude of this return, suggesting mid 40s to mid 50s surface dew points north of OK by 00Z. This should be adequate to support isolated high-based thunderstorms along the dryline in the western KS vicinity during the late afternoon to early evening. This activity will pose a threat for isolated large hail and localized severe wind gusts. Still, morning HRRR runs are insistent that even this scenario will fail, with effectively no sustained deep convection along the entire dryline. During the evening, a strengthening low-level jet will yield warm theta-e advection tonight. This might support any lingering dryline storms spreading northeast towards the Mid-MO Valley or more likely the development of elevated thunderstorms where ascent can overcome the stout elevated mixed-layer. Steep mid-level lapse rates and favorable cloud-layer shear will conditionally support a few elevated supercells, although the predominant convective mode should tend towards clusters northeast of the surface warm front. Isolated large hail appears to be the main threat. ...WY to western SD/NE... An elongated upper trough over the Northwest should consolidate across the northern Great Plains tonight. This will occur as a piece of the strong mid-level jet across northern/central CA and the Sierras ejects across the central Rockies to the Black Hills vicinity. This strengthening flow regime and large-scale ascent will aid in scattered high-based, low-topped convection across WY this afternoon and spreading into western SD/NE this evening. With surface dew points only in the 20s to low 30s, buoyancy will likely remain scant. But inverted-v thermodynamic profiles will support a threat for sporadic severe wind gusts. ..Grams/Thornton.. 04/18/2023 Read more

No watches are valid as of Mon Apr 17 21:31:01 UTC 2023.

No Mesoscale Discussions are in effect as of Mon Apr 17 21:31:01 UTC 2023.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Mon Apr 17 2023 Valid 172000Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe wind gusts and small to marginally severe hail will be possible between 4 to 9 PM CDT across parts of west Texas and southeast New Mexico. ...Discussion... The only change made to the previous convective outlook is to remove low-severe probabilities over South FL. Convective overturning coupled with veering low-level flow --coincident with a cool front-- will combine to diminish the risk for severe thunderstorms the remainder of the afternoon. ..Smith.. 04/17/2023 .PREV DISCUSSION... /ISSUED 1123 AM CDT Mon Apr 17 2023/ ...Southeast FL... A near-term threat for a severe storm or two should persist for a couple more hours attendant to a minor southern-stream mid-level trough passing across the southern peninsula. Within a lingering combination of moderate buoyancy and deep-layer shear, weak supercells will remain capable of producing small to marginally severe hail and locally strong gusts. Low-level winds appear to be in the process of weakening and becoming more veered, which will result in a decreasing threat later this afternoon. ...West TX and southeast NM... Northwest of the more substantial moisture return, deep boundary-layer mixing will support at least isolated high-based thunderstorms along a lee trough during the late afternoon and early evening. Inverted-v thermodynamic profiles with DCAPE of 1000-1500 J/kg will favor strong to locally severe outflow gusts with semi-organized cells, based on the steep lapse rates and moderately elongated, straight hodographs. An LP-supercell with a marginal hail threat is plausible towards the Big Bend/Lower Pecos Valley owing to greater elongation of the hodograph and MLCAPE near 500 J/kg. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Mon Apr 17 2023 Valid 172000Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe wind gusts and small to marginally severe hail will be possible between 4 to 9 PM CDT across parts of west Texas and southeast New Mexico. ...Discussion... The only change made to the previous convective outlook is to remove low-severe probabilities over South FL. Convective overturning coupled with veering low-level flow --coincident with a cool front-- will combine to diminish the risk for severe thunderstorms the remainder of the afternoon. ..Smith.. 04/17/2023 .PREV DISCUSSION... /ISSUED 1123 AM CDT Mon Apr 17 2023/ ...Southeast FL... A near-term threat for a severe storm or two should persist for a couple more hours attendant to a minor southern-stream mid-level trough passing across the southern peninsula. Within a lingering combination of moderate buoyancy and deep-layer shear, weak supercells will remain capable of producing small to marginally severe hail and locally strong gusts. Low-level winds appear to be in the process of weakening and becoming more veered, which will result in a decreasing threat later this afternoon. ...West TX and southeast NM... Northwest of the more substantial moisture return, deep boundary-layer mixing will support at least isolated high-based thunderstorms along a lee trough during the late afternoon and early evening. Inverted-v thermodynamic profiles with DCAPE of 1000-1500 J/kg will favor strong to locally severe outflow gusts with semi-organized cells, based on the steep lapse rates and moderately elongated, straight hodographs. An LP-supercell with a marginal hail threat is plausible towards the Big Bend/Lower Pecos Valley owing to greater elongation of the hodograph and MLCAPE near 500 J/kg. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0216 PM CDT Mon Apr 17 2023 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR MUCH OF NEW MEXICO INTO PORTIONS OF THE SOUTHERN AND CENTRAL HIGH PLAINS.... ...New Mexico and the southern/central High Plains... Widespread critical fire-weather conditions are expected D2/Tuesday ahead of the approaching upper trough and strong mid-level flow. A sharpening dryline will support west/southwest surface winds of 20-25 mph within areas of RH below 15% from central and eastern NM into west TX. Farther north across the central High Plains, widespread critical fire-weather conditions are also expected. Despite some areas of wetting precipitation over the past 72 hours, rapid drying and strong downslope flow over the Rockies will support RH values below 15% with winds gust 20-25 mph. Less confidence in fuels exists farther north and east across portions of CO and NE given locally heavier precipitation. However, the strong winds and low humidity post dryline will likely still support a risk for critical fire-weather Tuesday afternoon. ..Lyons.. 04/17/2023 .PREV DISCUSSION... /ISSUED 0210 AM CDT Mon Apr 17 2023/ ...Synopsis... A mid-level trough will impinge on the Plains states tomorrow/Tuesday, resulting in surface low development and associated dry downslope flow across the central and southern High Plains. Widespread Elevated conditions are likely throughout the southern and central High Plains, with Critical highlights added where winds are expected to exceed 20 mph amid 10-15 percent RH and dry fuels. A mid-level trough and associated surface low will continue to drift away from the East Coast, though dry and breezy conditions should linger east of the Appalachians. Guidance consensus depicts 15+ mph sustained westerly surface winds overlapping 15-25 percent RH for at least a few hours Tuesday afternoon across southern VA. Fuels in the area are relatively dry despite green-up (given an ongoing drought). Elevated highlights have been added where the aforementioned dry and windy surface conditions overlap with fuels that have not experienced appreciable rainfall in the past week. ...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 0216 PM CDT Mon Apr 17 2023 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR MUCH OF NEW MEXICO INTO PORTIONS OF THE SOUTHERN AND CENTRAL HIGH PLAINS.... ...New Mexico and the southern/central High Plains... Widespread critical fire-weather conditions are expected D2/Tuesday ahead of the approaching upper trough and strong mid-level flow. A sharpening dryline will support west/southwest surface winds of 20-25 mph within areas of RH below 15% from central and eastern NM into west TX. Farther north across the central High Plains, widespread critical fire-weather conditions are also expected. Despite some areas of wetting precipitation over the past 72 hours, rapid drying and strong downslope flow over the Rockies will support RH values below 15% with winds gust 20-25 mph. Less confidence in fuels exists farther north and east across portions of CO and NE given locally heavier precipitation. However, the strong winds and low humidity post dryline will likely still support a risk for critical fire-weather Tuesday afternoon. ..Lyons.. 04/17/2023 .PREV DISCUSSION... /ISSUED 0210 AM CDT Mon Apr 17 2023/ ...Synopsis... A mid-level trough will impinge on the Plains states tomorrow/Tuesday, resulting in surface low development and associated dry downslope flow across the central and southern High Plains. Widespread Elevated conditions are likely throughout the southern and central High Plains, with Critical highlights added where winds are expected to exceed 20 mph amid 10-15 percent RH and dry fuels. A mid-level trough and associated surface low will continue to drift away from the East Coast, though dry and breezy conditions should linger east of the Appalachians. Guidance consensus depicts 15+ mph sustained westerly surface winds overlapping 15-25 percent RH for at least a few hours Tuesday afternoon across southern VA. Fuels in the area are relatively dry despite green-up (given an ongoing drought). Elevated highlights have been added where the aforementioned dry and windy surface conditions overlap with fuels that have not experienced appreciable rainfall in the past week. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0552 CONCERNING HEAVY SNOW FOR PORTIONS OF NORTHERN WISCONSIN AND LAKE SUPERIOR
Mesoscale Discussion 0552 NWS Storm Prediction Center Norman OK 0125 PM CDT Mon Apr 17 2023 Areas affected...Portions of northern Wisconsin and Lake Superior Concerning...Heavy snow Valid 171825Z - 172130Z SUMMARY...Heavy snowfall with rates 1-2 inches per hour expected to continue through late afternoon. DISCUSSION...A band of moderate to heavy snow continues across portions of Lake Superior and northern Wisconsin behind a strong surface low and evident TROWAL. Northwesterly flow across Lake Superior has led to a band of locally very heavy snow, with mesoscale enhancement from moisture fetch across the lake and upslope flow. 1.5-2"/hr rates have been observed within this bad. Hi-res ensemble guidance indicates that 1-2"/hr rates could continue over the next couple of hours. Expect quick accumulations with periods of reduced visibility, as winds gusts up to 25-30 mph are also being observed. ..Thornton/Grams.. 04/17/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH... LAT...LON 46559201 47009160 47179132 47459097 47669053 47609044 47449061 47289069 47119082 46939097 46799108 46649111 46459117 46319131 46299173 46389194 46559201 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Mon Apr 17 2023 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN AND CENTRAL GREAT PLAINS STATES WESTWARD INTO WYOMING... ...SUMMARY... Isolated severe thunderstorms are possible from parts of the southern Great Plains northward into the Mid Missouri Valley and westward into Wyoming. Severe gusts and large hail will be the hazards with the stronger storms Tuesday afternoon into Tuesday night. ...Synopsis... A large-scale mid-level trough will be situated over the northwest part of the Lower 48 states on Tuesday. A mid-level speed max initially over the Sierra Nevada will quickly move through the base of the trough and reach the Dakotas by daybreak Wednesday. In the low levels, surface high pressure will reside over the Southeast while a surface trough/dryline sharpens over the Great Plains and induces strengthening southerly low level flow over the central-southern High Plains. A surface low will gradually deepen and migrate to the western Dakotas from WY during the period. ...Central-Southern Great Plains into WY... Southerly low-level flow will advect the initial stage of moisture return northward from the southern Great Plains into the central Great Plains during the day. Strong heating near the dryline/surface trough over western KS will result in very steep low-level lapse rates and deeply mixed profiles on the north periphery of 50s dewpoints. By mid afternoon, 1500-2000 J/kg SBCAPE is forecast from western KS southward into northwest TX. Strongly veering flow in the low to mid levels will result in 30-40 kt effective shear. Although moisture will be marginal, localized erosion of the cap is expected with isolated to widely scattered storms possible. Farther south over western OK/northwest TX, widely spaced and lower thunderstorm coverage is expected. Farther northwest over central WY, the arrival of the speed max during the afternoon within a narrow plume of adequate moisture --resulting in weak surface-based buoyancy-- will favor diurnal storm development. Very steep lapse rates and strong southwesterly low to mid-level flow will favor isolated severe gusts with the larger cores. Additional storms and some increase in storm coverage may occur by early evening towards the SD/WY border. Isolated severe gusts/large hail are possible before this activity gradually weakens during the evening. ...Low to Mid MO Valley Tuesday night... During the evening into the overnight, a strengthening southerly LLJ and associated warm air advection will favor scattered thunderstorms developing primarily overnight on the eastern periphery of steep 700-500 mb lapse rates. A few of the stronger storms will potentially be capable of large hail given the ample cloud-layer shear and elevated buoyancy. ..Smith.. 04/17/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Mon Apr 17 2023 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN AND CENTRAL GREAT PLAINS STATES WESTWARD INTO WYOMING... ...SUMMARY... Isolated severe thunderstorms are possible from parts of the southern Great Plains northward into the Mid Missouri Valley and westward into Wyoming. Severe gusts and large hail will be the hazards with the stronger storms Tuesday afternoon into Tuesday night. ...Synopsis... A large-scale mid-level trough will be situated over the northwest part of the Lower 48 states on Tuesday. A mid-level speed max initially over the Sierra Nevada will quickly move through the base of the trough and reach the Dakotas by daybreak Wednesday. In the low levels, surface high pressure will reside over the Southeast while a surface trough/dryline sharpens over the Great Plains and induces strengthening southerly low level flow over the central-southern High Plains. A surface low will gradually deepen and migrate to the western Dakotas from WY during the period. ...Central-Southern Great Plains into WY... Southerly low-level flow will advect the initial stage of moisture return northward from the southern Great Plains into the central Great Plains during the day. Strong heating near the dryline/surface trough over western KS will result in very steep low-level lapse rates and deeply mixed profiles on the north periphery of 50s dewpoints. By mid afternoon, 1500-2000 J/kg SBCAPE is forecast from western KS southward into northwest TX. Strongly veering flow in the low to mid levels will result in 30-40 kt effective shear. Although moisture will be marginal, localized erosion of the cap is expected with isolated to widely scattered storms possible. Farther south over western OK/northwest TX, widely spaced and lower thunderstorm coverage is expected. Farther northwest over central WY, the arrival of the speed max during the afternoon within a narrow plume of adequate moisture --resulting in weak surface-based buoyancy-- will favor diurnal storm development. Very steep lapse rates and strong southwesterly low to mid-level flow will favor isolated severe gusts with the larger cores. Additional storms and some increase in storm coverage may occur by early evening towards the SD/WY border. Isolated severe gusts/large hail are possible before this activity gradually weakens during the evening. ...Low to Mid MO Valley Tuesday night... During the evening into the overnight, a strengthening southerly LLJ and associated warm air advection will favor scattered thunderstorms developing primarily overnight on the eastern periphery of steep 700-500 mb lapse rates. A few of the stronger storms will potentially be capable of large hail given the ample cloud-layer shear and elevated buoyancy. ..Smith.. 04/17/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Mon Apr 17 2023 Valid 171700Z - 181200Z The previous forecast remains valid with only minor adjustments for the latest guidance. Isolated dry thunderstorms are expected over portions of the southern High Plains along with gusty winds and low humidity. Locally elevated fire-weather conditions are also possible across the eastern US, but confidence remains too low to add an Elevated area given widespread wetting rain. Please see the previous discussion for more information. ..Lyons.. 04/17/2023 .PREV DISCUSSION... /ISSUED 0209 AM CDT Mon Apr 17 2023/ ...Synopsis... A mid-level ridge will overspread the Plains states as an upper trough pivots toward New England. A departing surface low will encourage broad, dry westerly surface winds across much of the OH/TN Valleys and points eastward. Surface lee troughing across the southern High Plains will also develop by afternoon peak heating, encouraging both dry/windy surface conditions, and isolated dry thunderstorm development. ...Southern High Plains... By afternoon peak heating, 15 mph sustained southerly surface winds overlapping 15-20 percent RH are likely across portions of northeast NM into the TX and OK Panhandles and northwestern OK. Elevated highlights have been added where the most favorable overlap of dry/windy conditions and receptive fuels exists. Deep-layer ascent overspreading a relatively deep and dry but marginally buoyant boundary layer will encourage high-based thunderstorm development during the afternoon. The storms should be fast moving and isolated enough such that appreciable rainfall accumulations will be unlikely. Isolated dry thunderstorm highlights have been introduced where lightning strikes may occur amid dry grasses. ...OH/TN Valleys into the Appalachians... Widespread breezy, occasionally dry conditions are likely to the south of the surface low, with relative humidity dropping into the 20-30 percent range by afternoon peak heating. Several areas have received appreciable rainfall accumulations within the past week. As such, the potential for wildfire-spread should remain localized. ...Please see www.spc.noaa.gov/fire for graphic product... Read more