Severe Storms

MD 0487 CONCERNING BLIZZARD FOR PORTIONS OF CENTRAL AND EASTERN NORTH DAKOTA
Mesoscale Discussion 0487 NWS Storm Prediction Center Norman OK 0102 PM CDT Wed Apr 05 2023 Areas affected...Portions of central and eastern North Dakota Concerning...Blizzard Valid 051802Z - 052200Z SUMMARY...Localized blizzard conditions are expected across portions of central and eastern North Dakota through the remainder of the afternoon. DISCUSSION...On the backside of a deep/vertically stacked low-pressure system centered over the Upper MS Valley, surface observations and regional VWP data show strong deep-layer northwesterly winds overspreading North Dakota this afternoon. During the next couple of hours, strengthening winds (around 40 kt in the boundary layer) will support frequent gusts upwards of 35-40 mph. These gusts, combined with sufficiently cold surface temperatures and ongoing light/moderate snow (and antecedent snowpack) will favor localized blizzard conditions through the remainder of the afternoon. Blowing snow model output suggests that 35+ mph gusts will support blizzard conditions in rural areas, with localized blizzard conditions also possible in more urbanized areas/towns with frequent gusts of 40+ mph. ..Weinman.. 04/05/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 47840097 48480124 49050125 49120034 49109896 48909848 48449827 47829799 46759751 46189732 45969767 45969832 46019971 46380016 47070054 47840097 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Wed Apr 05 2023 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN APPALACHIANS INTO THE MID-ATLANTIC AND ACROSS DEEP SOUTH AND COASTAL TEXAS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Appalachians into the Mid-Atlantic, as well as across southern/coastal Texas, Thursday afternoon and evening. ...Synopsis... The upper wave currently over the north-central CONUS is expected to continue lifting to the northeast into southeastern Canada over the next 48 hours. By Thursday afternoon, a nearly straight mid-level jet streak will likely be in place from the Great Lakes region into southern Quebec. At the surface, a trailing cold front, currently pushing eastward across the Midwest and southern U.S., is expected to slow as it migrates into the Mid-Atlantic, Southeast, and TX Gulf Coast regions. Thunderstorms will likely be ongoing along portions of this boundary at the start of the period, and their longevity through the morning/early afternoon hours is uncertain due to an increasing displacement from stronger synoptic ascent to the north. Redevelopment along this boundary by late afternoon/early evening appears likely across the southeast states to the Mid-Atlantic region and may feature a few strong to severe thunderstorms. ...Mid-Atlantic and southern Appalachians... Thunderstorm development along the cold front appears probable along the southern Appalachians into the Mid-Atlantic region Thursday afternoon. The moist air mass currently in place across the Carolinas (characterized by mid/upper 60s dewpoints) will advect northward through the day and should support MLCAPE values upwards of 1000-1500 J/kg. Although the main upper-level jet axis will be displaced to the north of the region, 40-50 knot mid-level flow should provide favorable deep-layer shear for organized convection. While the overall parameter space will support supercells, storm motions and deep-layer shear vectors largely oriented along the initiating cold front suggest that initially discrete cells may grow upscale into clusters and/or lines. It remains somewhat uncertain how quickly this transition will take place, and a more robust hail/wind threat may emerge if discrete modes can be maintained through the afternoon. This conditional threat appears most probable across the DelMarVa/southeast VA region where recent CAM guidance shows the highest UH concentration, implying a regionally higher potential for organized discrete storms; however, confidence in this scenario remains too limited for higher risk probabilities. ...Deep South and coastal Texas... The cold front is expected to reach the TX Gulf coast by tonight/early Thursday morning and will likely stall offshore by late afternoon. Consequently, the potential for surface-based buoyancy will likely be limited to coastal areas. However, 7-8 C/km mid-level lapse rates (sampled in morning RAOBs) are expected to overspread deep south TX over the frontal intrusion. The approach of a weak mid-level perturbation (evident off the southern CA coast in water-vapor imagery) will likely augment low to mid-level isentropic ascent over the frontal surface, resulting in a broad region of precipitation with embedded thunderstorms. Given effective deep-layer shear on the order of 30-40 knots, a few stronger, more organized elevated cells are possible and may pose an isolated large hail threat. ..Moore/Gleason.. 04/05/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1144 AM CDT Wed Apr 05 2023 Valid 051700Z - 061200Z Trimmed the eastern edge of the Elevated delineation based on morning frontal/dryline position. Otherwise, no changes were needed. See previous discussion below. ..Bentley.. 04/05/2023 .PREV DISCUSSION... /ISSUED 1248 AM CDT Wed Apr 05 2023/ ...Synopsis... Gusty northwesterly post-frontal winds in combination with a very dry air mass will allow for Elevated fire weather conditions across portions of Texas, from the Edwards Plateau into central and south-central Texas today. Relative humidity reductions to around 15-20 percent (locally as low as 10 percent) are expected with winds around 10-15 mph. Within this region, localized terrain-driven Critical fire weather conditions will be possible. HREF ensemble guidance shows the highest chances for this to be near the Edwards Plateau and southward for a couple of hours around mid-morning/early afternoon. The short duration and localized nature of any Critical conditions will preclude the need to include a Critical area with this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0115 Status Updates
STATUS REPORT ON WW 115 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SQUITIERI..04/04/23 ATTN...WFO...DMX...DVN...LSX...ILX...EAX... STATUS REPORT FOR WT 115 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC001-011-015-067-071-073-085-095-109-131-155-161-175-177-187- 195-042140- IL . ILLINOIS COUNTIES INCLUDED ARE ADAMS BUREAU CARROLL HANCOCK HENDERSON HENRY JO DAVIESS KNOX MCDONOUGH MERCER PUTNAM ROCK ISLAND STARK STEPHENSON WARREN WHITESIDE IAC001-003-007-009-011-013-015-019-027-029-031-039-045-049-051- 053-055-057-061-073-075-077-079-083-087-095-097-099-101-103-105- 107-111-113-115-117-121-123-125-127-135-139-153-157-159-163-169- 171-173-175-177-179-181-183-185-187-042140- IA . IOWA COUNTIES INCLUDED ARE ADAIR ADAMS APPANOOSE AUDUBON BENTON BLACK HAWK BOONE BUCHANAN CARROLL CASS CEDAR CLARKE Read more

WW 0115 Status Updates
STATUS REPORT ON WW 115 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SQUITIERI..04/04/23 ATTN...WFO...DMX...DVN...LSX...ILX...EAX... STATUS REPORT FOR WT 115 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC001-011-015-067-071-073-085-095-109-131-155-161-175-177-187- 195-042140- IL . ILLINOIS COUNTIES INCLUDED ARE ADAMS BUREAU CARROLL HANCOCK HENDERSON HENRY JO DAVIESS KNOX MCDONOUGH MERCER PUTNAM ROCK ISLAND STARK STEPHENSON WARREN WHITESIDE IAC001-003-007-009-011-013-015-019-027-029-031-039-045-049-051- 053-055-057-061-073-075-077-079-083-087-095-097-099-101-103-105- 107-111-113-115-117-121-123-125-127-135-139-153-157-159-163-169- 171-173-175-177-179-181-183-185-187-042140- IA . IOWA COUNTIES INCLUDED ARE ADAIR ADAMS APPANOOSE AUDUBON BENTON BLACK HAWK BOONE BUCHANAN CARROLL CASS CEDAR CLARKE Read more

WW 115 TORNADO IA IL MO 041950Z - 050300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 115 NWS Storm Prediction Center Norman OK 250 PM CDT Tue Apr 4 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Central and Southeast Iowa Northwest Illinois Northern Missouri * Effective this Tuesday afternoon and evening from 250 PM until 1000 PM CDT. * Primary threats include... Several tornadoes and a couple intense tornadoes likely Widespread large hail and isolated very large hail events to 3.5 inches in diameter likely Scattered damaging wind gusts to 70 mph likely SUMMARY...Intense thunderstorms will increase in coverage this afternoon across the watch area, with supercells expected. Very large hail and tornadoes may occur in the strongest cells. The tornado watch area is approximately along and 110 statute miles north and south of a line from 50 miles west northwest of Lamoni IA to 45 miles south southeast of Moline IL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 114... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 3.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25035. ...Hart Read more

MD 0460 CONCERNING HEAVY SNOW FOR PORTIONS OF NORTH-CENTRAL/NORTHEASTERN SD INTO SOUTHEASTERN ND AND FAR WESTERN MN
Mesoscale Discussion 0460 NWS Storm Prediction Center Norman OK 0345 PM CDT Tue Apr 04 2023 Areas affected...Portions of north-central/northeastern SD into southeastern ND and far western MN Concerning...Heavy snow Valid 042045Z - 050045Z SUMMARY...Moderate to heavy snow with rates near 1 in/hr (locally higher) and visibility reductions in blowing snow are possible this afternoon/evening. DISCUSSION...Latest water vapor loops and regional VWP data indicate a strong southwesterly mid/upper-level jet streak crossing the central Plains, which will continue northeastward this afternoon. As the left-exit region of the jet streak gradually overspreads the northern Plains (ND/SD) during the next few hours, a related band of isentropic ascent (strong 0-3-km veering evident in regional VWP data) will strengthen over the region. As the strengthening large-scale ascent intersects the lower portions of a relatively deep/saturated dendritic growth zone (per 12Z observed and RAP forecast soundings), the potential for moderate to heavy snow with rates up to 1 in/hr (locally higher) will increase this afternoon/evening. The highest snowfall rates should generally be focused along/north of a northeast/southwest-oriented 700-mb thermal gradient extending from southeast ND into north-central SD in the 22-00Z time frame (and beyond). In addition, given cold surface temperatures and a tightening surface pressure gradient coincident with the moderate to heavy snow, blowing snow with visibility reductions are expected. However, the potential for near-blizzard conditions will become an increasing concern into the overnight hours as boundary-layer winds continue to strengthen amid continued snowfall. ..Weinman.. 04/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...ABR...BIS... LAT...LON 46290064 46919999 47349910 47779826 48019751 47989678 47559630 46939626 46559644 46169709 45759794 45489920 45690050 46290064 Read more

MD 0459 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHWESTERN LOWER MICHIGAN
Mesoscale Discussion 0459 NWS Storm Prediction Center Norman OK 0322 PM CDT Tue Apr 04 2023 Areas affected...portions of southwestern Lower Michigan Concerning...Severe potential...Watch unlikely Valid 042022Z - 042215Z Probability of Watch Issuance...20 percent SUMMARY...A couple instances of large hail or a damaging gust may accompany any of the more mature storms that can persist across southern Lake Michigan. The severe threat is expected to remain isolated and a WW issuance is not anticipated. DISCUSSION...Multiple supercell structures with a history of efficient severe hail production and damaging wind gusts are moving across southern Lake Michigan within a low-level warm-air advection regime. Buoyancy is relatively scant across southern Lower Michigan. Still, the advection of some elevated CAPE amid 8 C/km mid-level lapse rates suggests that any storms that can persist across the lake with appreciable intensity may be capable of producing at least marginally severe hail and/or a damaging gust. This is especially the case for a supercell approaching northern Berrien County into Van Buren County. Nonetheless, any severe threat that materializes should remain isolated, and a WW issuance is not expected. ..Squitieri/Hart.. 04/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...GRR... LAT...LON 42108655 42738632 42908618 42908573 42698535 42368522 42038525 41898558 41928624 41938655 42108655 Read more

MD 0458 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF NORTH TEXAS...EASTERN OKLAHOMA...WESTERN ARKANSAS INTO SOUTHWESTERN MISSOURI AND SOUTHEASTERN KANSAS
Mesoscale Discussion 0458 NWS Storm Prediction Center Norman OK 0306 PM CDT Tue Apr 04 2023 Areas affected...portions of North Texas...eastern Oklahoma...western Arkansas into southwestern Missouri and southeastern Kansas Concerning...Severe potential...Watch possible Valid 042006Z - 042200Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorms may pose a risk initially for hail across portions of North TX/OK into portions of western AR. Additional development along the dryline is possible in eastern KS and western MO. Uncertainty on the exact timing and location of storm development is very high. Trends are being monitored for a possible weather watch. DISCUSSION...As of 2000 UTC, afternoon observations showed a broad plume of cirrus, associated with a deep western US trough, overspreading a warming and moistening air mass across much of the ArkLaTex and southern Plains. Within the broad cirrus, several CI attempts have been noted along and east of a confluence band ahead of the dryline in North TX. Surface temperatures near 80 and dewpoints in the upper 60s to low 70s F are supporting moderate instability with MLCAPE of 2000 J/kg. With the main trough lagging to the west, forcing for ascent is rather nebulous over much of the region through the afternoon. This is evident in SPC mesoanalysis which shows considerable inhibition still in place below a robust EML. Despite the inhibition, strong flow aloft is supporting long elongated hodographs with effective shear of 50-60 kt favorable for supercells with the potential for large hail. Weaker low-level shear may limit the initial tornado threat if supercells are able to mature. However as forcing increases toward the evening, a greater threat for tornadoes may evolve. Recent visible and radar trends show several weak, likely elevated updrafts over the Red river are persisting despite the inhibition. As updrafts cluster and shift north, a more sustained/sustained storm may evolve from these initial attempts. Diurnal heating/weak ascent may also support additional, isolated development around the dryline from east/northeastern OK into eastern KS. Poor handling of the situation by Hi-res guidance and nebulous forcing lends low confidence in additional convective development and the overall evolution. None the less, the strongly sheared and destabilizing air mass appears conditionally favorable for large to very large hail and possibly tornadoes late this afternoon into the evening. A greater threat will likely evolve overnight as the main trough ejects eastward. Trends will be monitored or a possible weather watch this afternoon but uncertainty is high. ..Lyons/Hart.. 04/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SGF...SHV...EAX...TSA...TOP...ICT...FWD... OUN... LAT...LON 32889550 32639719 32699788 33149825 33799804 34069798 34409764 34819718 35429671 36009641 36699624 38009569 38139522 38209434 38059368 37199279 36109280 34689342 34099372 33479434 33179477 32889550 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Apr 04 2023 Valid 042000Z - 051200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF IOWA...WESTERN ILLINOIS...FAR SOUTHEAST OKLAHOMA AND WESTERN ARKANSAS... ...SUMMARY... Tornadoes, severe thunderstorm gusts and large hail are likely today and tonight from the Upper Great Lakes to central Texas. Tornado potential is focused today over parts of Iowa/Illinois this afternoon, and especially tonight over parts of the Ozarks to the Arklatex region. ...Iowa and northern Missouri... The most substantial change for this update is a westward expansion of the higher tornado probabilities across parts of central/western IA and far northern MO. Recent hi-res guidance continues to suggest a corridor of convective initiation across northwest MO to western IA around 22 UTC, and this idea is supported by recent surface and satellite observations (see MCD #456 for additional short-term details). Elevated convection is also noted across north TX into southern OK. This activity is expected to intensify as it tracks northeast through the afternoon/evening into the higher risk probabilities (see forthcoming MCD #457 for additional details). ..Moore/Jewell.. 04/04/2023 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Apr 04 2023/ ...IA/IL/MO... A large upper trough is deepening over the Rockies today, with an 80-90 knot mid level speed max rotating across the Plains. The associated surface low will track from central KS into IA this afternoon while a warm front lifts northward across eastern IA and northern IL. This will result in a large unstable warm sector across parts of IA/IL/MO where forecast soundings show strong low-level shear profiles and ample CAPE for severe/supercell storms. This scenario is quite different than last Friday, with more concerns for capping in the warm sector and pockets of dry low-level air that reduces confidence in the number of storms and intense tornado potential. Nevertheless, scattered supercells are expected later today with very large hail, tornadoes, and damaging winds expected. Isolated strong tornadoes may occur. By mid-late afternoon, thunderstorms are expected to erupt near the surface low and along the trailing cold front over central IA/northern MO. Intense wind fields will be present in this area, along with strong linear forcing. Large hail and damaging winds are expected with this activity, along with the risk of supercell and/or QLCS tornadoes. ...ArkLaTex into southern MO/IL Tonight... By early evening, forecast soundings from most 12z guidance shows that a broad area of high conditional risk of tornadic supercells will develop from eastern OK into much of AR and southern MO. This area will still be somewhat capped and the mechanisms for convective initiation are uncertain. However, a consensus of guidance shows multiple clusters of supercells forming across this area and persisting through the evening. Wind fields will strengthen throughout the night and capping will weaken, leading to a serious concern for nocturnal tornadoes over the southern MDT risk area in MO/AR. Again, model guidance provides confidence in the risk of widely scattered supercells throughout the night across the area, although details of location and timing are uncertain. Strong or even violent tornadoes are possible in this scenario. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Apr 04 2023 Valid 042000Z - 051200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF IOWA...WESTERN ILLINOIS...FAR SOUTHEAST OKLAHOMA AND WESTERN ARKANSAS... ...SUMMARY... Tornadoes, severe thunderstorm gusts and large hail are likely today and tonight from the Upper Great Lakes to central Texas. Tornado potential is focused today over parts of Iowa/Illinois this afternoon, and especially tonight over parts of the Ozarks to the Arklatex region. ...Iowa and northern Missouri... The most substantial change for this update is a westward expansion of the higher tornado probabilities across parts of central/western IA and far northern MO. Recent hi-res guidance continues to suggest a corridor of convective initiation across northwest MO to western IA around 22 UTC, and this idea is supported by recent surface and satellite observations (see MCD #456 for additional short-term details). Elevated convection is also noted across north TX into southern OK. This activity is expected to intensify as it tracks northeast through the afternoon/evening into the higher risk probabilities (see forthcoming MCD #457 for additional details). ..Moore/Jewell.. 04/04/2023 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Apr 04 2023/ ...IA/IL/MO... A large upper trough is deepening over the Rockies today, with an 80-90 knot mid level speed max rotating across the Plains. The associated surface low will track from central KS into IA this afternoon while a warm front lifts northward across eastern IA and northern IL. This will result in a large unstable warm sector across parts of IA/IL/MO where forecast soundings show strong low-level shear profiles and ample CAPE for severe/supercell storms. This scenario is quite different than last Friday, with more concerns for capping in the warm sector and pockets of dry low-level air that reduces confidence in the number of storms and intense tornado potential. Nevertheless, scattered supercells are expected later today with very large hail, tornadoes, and damaging winds expected. Isolated strong tornadoes may occur. By mid-late afternoon, thunderstorms are expected to erupt near the surface low and along the trailing cold front over central IA/northern MO. Intense wind fields will be present in this area, along with strong linear forcing. Large hail and damaging winds are expected with this activity, along with the risk of supercell and/or QLCS tornadoes. ...ArkLaTex into southern MO/IL Tonight... By early evening, forecast soundings from most 12z guidance shows that a broad area of high conditional risk of tornadic supercells will develop from eastern OK into much of AR and southern MO. This area will still be somewhat capped and the mechanisms for convective initiation are uncertain. However, a consensus of guidance shows multiple clusters of supercells forming across this area and persisting through the evening. Wind fields will strengthen throughout the night and capping will weaken, leading to a serious concern for nocturnal tornadoes over the southern MDT risk area in MO/AR. Again, model guidance provides confidence in the risk of widely scattered supercells throughout the night across the area, although details of location and timing are uncertain. Strong or even violent tornadoes are possible in this scenario. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Tue Apr 04 2023 Valid 051200Z - 061200Z Only minor adjustments were made to the Elevated area from central Texas to the Edwards Plateau. The primary adjustment was moving it north and northwest where dry northwesterly flow is indicated by latest high resolution guidance. See previous discussion below. ..Bentley.. 04/04/2023 .PREV DISCUSSION... /ISSUED 0127 AM CDT Tue Apr 04 2023/ ...Synopsis... A dry post-frontal air mass and northwesterly breezes will allow for Elevated fire weather conditions across portions of Texas from the Concho Valley to the Edwards Plateau and into portions of Central Texas. Relative humidity reductions to around 10-15 percent with sustained northwest winds at 10-15 mph will be possible. Winds may be locally as high as 20 mph, with some period of terrain-driven Critical fire weather conditions possible. Given the localized nature of any Critical conditions, an Elevated delineation was most appropriate. Isolated terrain-driven Elevated to Critical fire weather conditions will also be possible in eastern New Mexico. Given small the coverage of potential Elevated or Critical conditions, no area was included. Relative humidity may drop as low as 10-15 percent with winds around 10-20 mph. ...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 0257 PM CDT Tue Apr 04 2023 Valid 051200Z - 061200Z Only minor adjustments were made to the Elevated area from central Texas to the Edwards Plateau. The primary adjustment was moving it north and northwest where dry northwesterly flow is indicated by latest high resolution guidance. See previous discussion below. ..Bentley.. 04/04/2023 .PREV DISCUSSION... /ISSUED 0127 AM CDT Tue Apr 04 2023/ ...Synopsis... A dry post-frontal air mass and northwesterly breezes will allow for Elevated fire weather conditions across portions of Texas from the Concho Valley to the Edwards Plateau and into portions of Central Texas. Relative humidity reductions to around 10-15 percent with sustained northwest winds at 10-15 mph will be possible. Winds may be locally as high as 20 mph, with some period of terrain-driven Critical fire weather conditions possible. Given the localized nature of any Critical conditions, an Elevated delineation was most appropriate. Isolated terrain-driven Elevated to Critical fire weather conditions will also be possible in eastern New Mexico. Given small the coverage of potential Elevated or Critical conditions, no area was included. Relative humidity may drop as low as 10-15 percent with winds around 10-20 mph. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0457 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR NORTHEAST IOWA...FAR SOUTHEAST MINNESOTA...AND SOUTHWEST/CENTRAL WISCONSIN
Mesoscale Discussion 0457 NWS Storm Prediction Center Norman OK 0254 PM CDT Tue Apr 04 2023 Areas affected...northeast Iowa...far southeast Minnesota...and southwest/central Wisconsin Concerning...Severe potential...Watch likely Valid 041954Z - 042230Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms are expected to develop in the 22-00z/5pm-7pm CDT time frame. Large hail, damaging gusts and a couple tornadoes appear likely through this evening. A watch will likely be needed in the next couple of hours. DISCUSSION...Some uncertainty remains regarding how far north the surface warm front will advance across the region through this evening. Most guidance suggest the boundary will lift into far southern WI by this evening. Thunderstorms are expected to develop in the vicinity of the surface low across western/central IA in the next couple hours. Storms will track northeast near, or to the cool side, of the northward-advancing warm front. This will likely result in most convection remaining elevated, though a couple of storms could become rooted in the frontal zone across northeast IA or far southwest WI. The storms that can ingest better quality low-level moisture and vorticity along the boundary will have a better opportunity to produce a tornado. However, current thinking is that convection will largely remain elevated. Nevertheless, strong vertical shear will support supercells. Very steep midlevel lapse rates will support MUCAPE around 500-1500 J/kg and large hail will be possible. Fast moving storms, coupled with strong deep-layer flow also will support some damaging wind potential. A relative max in severe potential will exist across southern portions of the MCD where at least some chance of near surface-based convection will exist within the warm frontal zone. With northward extent, overall potential will gradually lessen. A watch will likely be needed in the next couple of hours. ..Leitman/Hart.. 04/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...LOT...MKX...DVN...ARX...MPX...DMX... LAT...LON 42419421 42639424 42909410 43609329 44059229 44159170 44359055 44278942 44168904 43898880 43638873 43048877 42538916 42438961 42499184 42419421 Read more

WW 0114 Status Updates
STATUS REPORT ON WW 114 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SE MMO TO 25 ESE RFD. ..SQUITIERI..04/04/23 ATTN...WFO...LOT... STATUS REPORT FOR WS 114 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC007-031-043-089-091-097-111-041940- IL . ILLINOIS COUNTIES INCLUDED ARE BOONE COOK DUPAGE KANE KANKAKEE LAKE MCHENRY INC089-041940- IN . INDIANA COUNTIES INCLUDED ARE LAKE LMZ740-741-742-743-744-041940- CW . ADJACENT COASTAL WATERS INCLUDED ARE WINTHROP HARBOR TO WILMETTE HARBOR IL Read more

WW 0114 Status Updates
STATUS REPORT ON WW 114 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SE MMO TO 25 ESE RFD. ..SQUITIERI..04/04/23 ATTN...WFO...LOT... STATUS REPORT FOR WS 114 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC007-031-043-089-091-097-111-041940- IL . ILLINOIS COUNTIES INCLUDED ARE BOONE COOK DUPAGE KANE KANKAKEE LAKE MCHENRY INC089-041940- IN . INDIANA COUNTIES INCLUDED ARE LAKE LMZ740-741-742-743-744-041940- CW . ADJACENT COASTAL WATERS INCLUDED ARE WINTHROP HARBOR TO WILMETTE HARBOR IL Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Tue Apr 04 2023 Valid 051200Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER OHIO RIVER VALLEY TO THE GREAT LAKES REGION... ...SUMMARY... Scattered severe storms posing a risk for strong tornadoes and large hail are expected in a corridor across eastern Illinois through Lower Michigan Wednesday, with organizing clusters or lines of storms accompanied by potentially damaging wind gusts, and a few tornadoes across the Ohio Valley vicinity. ...Synopsis... Recent water-vapor imagery continues to depict a robust upper wave over the central Rockies with an accompanying surface low noted in mid-morning surface observations across the central Plains. Guidance continues to show reasonably good agreement in the evolution of these features over the next 48 hours as the upper wave ejects into the Plains and the surface low tracks northeastward through the Upper Great Lakes region by late Wednesday. A trailing cold front is expected to impinge on a broad warm sector beginning late tonight as it migrates southeast through the Midwest, mid-MS River Valley, and TX Gulf coast through the day Wednesday. Strong to severe thunderstorms will likely be ongoing at the beginning of the period along much of the cold front, and more organized cells and/or clusters may persist into the afternoon hours given the strongly sheared environment and diurnal warming/destabilization. Locations that see weakening of early-morning convection will likely see re-intensification either along the cold or residual outflow boundaries by late afternoon. Given the broad warm sector (featuring 60+ F dewpoints) and strong flow over the region, organized convection appears likely across a large swath of the Midwest to south-central CONUS. One notable trend for this update is a westward shift in probabilities driven by a slower eastward progression of the synoptic wave/surface low that has consistently emerged in recent global and mesoscale guidance. ...IL to OH and lower MI... Confidence in the severe threat remains highest across portions of the Midwest. Open warm sector convection may be ongoing by 12 UTC across parts of eastern MO/IL and will propagate into parts of IN, OH, and lower MI through the day. Poleward moisture advection in the wake of morning convection will maintain a buoyant air mass prior to the frontal passage in the late morning/afternoon when a second round of storms appears likely. The combination of the mid-level jet max aloft and strong low-level pressure gradient winds will result in a strongly sheared environment featuring effective bulk shear values near 50s knots and 150-200 m2/s2 of 0-1 km SRH. This kinematic environment will support a tornado threat, including the potential for a strong tornado, especially if more discrete storm modes can be realized (though it is unclear if boundary-relative storm motions and deep-layer shear vectors will be sufficient to maintain discrete modes given considerable along-boundary mean flow). Regardless, the strong low-level flow will support the potential for damaging to severe winds. ...Middle MS and lower OH River Valleys... Forcing for ascent along the middle MS and lower OH River Valleys is expected to diminish through the day as stronger synoptic ascent becomes increasingly displaced to the north/northeast. Strong flow aloft on the southern periphery of the jet max will support elongated hodographs, which when coupled with 1500-2000 J/kg MLCAPE and residual ascent along the slowing cold front, will likely be favorable for semi-discrete cells to clusters with an attendant threat for large hail, damaging winds, and perhaps a tornado. ..Moore/Jewell.. 04/04/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Tue Apr 04 2023 Valid 051200Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER OHIO RIVER VALLEY TO THE GREAT LAKES REGION... ...SUMMARY... Scattered severe storms posing a risk for strong tornadoes and large hail are expected in a corridor across eastern Illinois through Lower Michigan Wednesday, with organizing clusters or lines of storms accompanied by potentially damaging wind gusts, and a few tornadoes across the Ohio Valley vicinity. ...Synopsis... Recent water-vapor imagery continues to depict a robust upper wave over the central Rockies with an accompanying surface low noted in mid-morning surface observations across the central Plains. Guidance continues to show reasonably good agreement in the evolution of these features over the next 48 hours as the upper wave ejects into the Plains and the surface low tracks northeastward through the Upper Great Lakes region by late Wednesday. A trailing cold front is expected to impinge on a broad warm sector beginning late tonight as it migrates southeast through the Midwest, mid-MS River Valley, and TX Gulf coast through the day Wednesday. Strong to severe thunderstorms will likely be ongoing at the beginning of the period along much of the cold front, and more organized cells and/or clusters may persist into the afternoon hours given the strongly sheared environment and diurnal warming/destabilization. Locations that see weakening of early-morning convection will likely see re-intensification either along the cold or residual outflow boundaries by late afternoon. Given the broad warm sector (featuring 60+ F dewpoints) and strong flow over the region, organized convection appears likely across a large swath of the Midwest to south-central CONUS. One notable trend for this update is a westward shift in probabilities driven by a slower eastward progression of the synoptic wave/surface low that has consistently emerged in recent global and mesoscale guidance. ...IL to OH and lower MI... Confidence in the severe threat remains highest across portions of the Midwest. Open warm sector convection may be ongoing by 12 UTC across parts of eastern MO/IL and will propagate into parts of IN, OH, and lower MI through the day. Poleward moisture advection in the wake of morning convection will maintain a buoyant air mass prior to the frontal passage in the late morning/afternoon when a second round of storms appears likely. The combination of the mid-level jet max aloft and strong low-level pressure gradient winds will result in a strongly sheared environment featuring effective bulk shear values near 50s knots and 150-200 m2/s2 of 0-1 km SRH. This kinematic environment will support a tornado threat, including the potential for a strong tornado, especially if more discrete storm modes can be realized (though it is unclear if boundary-relative storm motions and deep-layer shear vectors will be sufficient to maintain discrete modes given considerable along-boundary mean flow). Regardless, the strong low-level flow will support the potential for damaging to severe winds. ...Middle MS and lower OH River Valleys... Forcing for ascent along the middle MS and lower OH River Valleys is expected to diminish through the day as stronger synoptic ascent becomes increasingly displaced to the north/northeast. Strong flow aloft on the southern periphery of the jet max will support elongated hodographs, which when coupled with 1500-2000 J/kg MLCAPE and residual ascent along the slowing cold front, will likely be favorable for semi-discrete cells to clusters with an attendant threat for large hail, damaging winds, and perhaps a tornado. ..Moore/Jewell.. 04/04/2023 Read more

Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1136 AM CDT TUE APR 04 2023 ...Severe thunderstorms expected over parts of the Select a General Area this afternoon and tonight... * LOCATIONS... Western Arkansas Eastern Iowa Southern Missouri Northwest Illinois * HAZARDS... Several tornadoes, a few intense Scattered large hail, some baseball size Scattered damaging winds * SUMMARY... Tornadoes, severe thunderstorm gusts and large hail are possible today and tonight from the Upper Great Lakes to central Texas. Tornado potential is focused today over parts of Iowa/Illinois this afternoon, and especially tonight over parts of the Ozarks to the Arklatex region. Preparedness actions... Review your severe weather safety procedures for the possibility of dangerous weather today. Stay tuned to NOAA Weather Radio, weather.gov, or other media for watches and warnings. A tornado watch means that conditions are favorable for tornadoes to form during the next several hours. If a tornado warning is issued for your area, move to a place of safety, ideally in a basement or interior room on the lowest floor of a sturdy building. && Read more

Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1136 AM CDT TUE APR 04 2023 ...Severe thunderstorms expected over parts of the Select a General Area this afternoon and tonight... * LOCATIONS... Western Arkansas Eastern Iowa Southern Missouri Northwest Illinois * HAZARDS... Several tornadoes, a few intense Scattered large hail, some baseball size Scattered damaging winds * SUMMARY... Tornadoes, severe thunderstorm gusts and large hail are possible today and tonight from the Upper Great Lakes to central Texas. Tornado potential is focused today over parts of Iowa/Illinois this afternoon, and especially tonight over parts of the Ozarks to the Arklatex region. Preparedness actions... Review your severe weather safety procedures for the possibility of dangerous weather today. Stay tuned to NOAA Weather Radio, weather.gov, or other media for watches and warnings. A tornado watch means that conditions are favorable for tornadoes to form during the next several hours. If a tornado warning is issued for your area, move to a place of safety, ideally in a basement or interior room on the lowest floor of a sturdy building. && Read more