Severe Storms

MD 1377 CONCERNING SEVERE THUNDERSTORM WATCH 427... FOR PORTIONS OF SOUTHERN/CENTRAL IL INTO SOUTHERN/CENTRAL IN AND WESTERN/CENTRAL KY
Mesoscale Discussion 1377 NWS Storm Prediction Center Norman OK 0335 PM CDT Sat Jul 01 2023 Areas affected...portions of southern/central IL into southern/central IN and western/central KY Concerning...Severe Thunderstorm Watch 427... Valid 012035Z - 012230Z The severe weather threat for Severe Thunderstorm Watch 427 continues. SUMMARY...Damaging gusts and large hail threat will continue across portions of southern Illinois into western Kentucky and southwest Indiana the next few hours. An increasing severe risk is expected to develop late this afternoon into this evening downstream from WW 427 and a new watch will likely be needed. DISCUSSION...Intense, severe-warned cells are ongoing across southern IL and parts of western KY. MRMS MESH has indicated hail between 1-2 inch in diameter is possible with these storms as they track generally eastward across a moderate unstable airmass. Effective shear magnitudes around 35-45 kt are noted in objective guidance and regional VWP data. Over the past 30 minutes or so, more discrete cells over southern IL appear to be trying to organize into more of a forward propagating cluster. Damaging wind potential will increase with any upscale development with this activity. Further north and east of WW 427 across east-central IL into parts of central/southern IN and west-central KY, airmass recovery after morning convection appears to be well underway. Low-level inhibition has most eroded as temperatures have warmed into the mid/upper 80s with low/mid 70s dewpoints. The gradient of stronger instability is oriented across this area, and favorable shear is expected to persist as a midlevel shortwave impulse continues to eject across MO and into IL this evening. This should support a continued severe thunderstorm risk into this evening, and a downstream severe thunderstorm watch is likely. ..Leitman/Grams.. 07/01/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILN...LMK...IND...PAH...ILX...LSX... LAT...LON 37218688 37548844 37818938 38038954 38108957 38948946 39468913 39798851 39648686 39308556 39128522 38918508 38598507 38128521 37868530 37358574 37178637 37218688 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Sat Jul 01 2023 Valid 012000Z - 021200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO THIS EVENING ACROSS PARTS OF EAST CENTRAL AND SOUTHEAST MISSOURI...SOUTHERN ILLINOIS...SOUTHERN INDIANA AND WESTERN INTO CENTRAL KENTUCKY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE WEST TEXAS PERMIAN BASIN... ...SUMMARY... Thunderstorms may gradually consolidate and organize across parts of the middle Mississippi into lower Ohio Valley late this afternoon, accompanied by increasing potential for damaging wind gusts and perhaps a couple of tornadoes into this evening. ...20Z Update... Adjustments have been made to better account for the progression of synoptic and sub-synoptic features and associated trends concerning instability. An increase in thunderstorm development is ongoing across east central and southeast Missouri, aided by forcing associated with a smaller-scale perturbation/speed maximum within positively-tilted larger-scale mid-level troughing gradually shifting east of the central Great Plains. In the presence of strong deep-layer shear beneath a belt of 40+ kt southwesterly 500 mb flow across southeastern Missouri into south central Illinois, it still seems probable that upscale growing convection will become increasingly organized while propagating east of the Mississippi River late this afternoon. Easterly near-surface inflow into updrafts will be characterized by seasonably moist air with moderately large CAPE across southeastern Missouri through southern Illinois, Indiana and western Kentucky. Farther east, toward the Allegheny and Cumberland Plateau, prior convective outflow is maintaining considerable influence and potential for substantive destabilization to maintain activity remains more unclear. ..Kerr.. 07/01/2023 .PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Jul 01 2023/ ...Mid MS/OH Valleys... A modestly amplified shortwave trough over western NE/KS will progress into IA/MO by tonight, as embedded, convectively enhanced perturbations rotate around its southern and eastern periphery. One such perturbation near the Ozark Plateau will aid in scattered thunderstorm development as it impinges on the Mid-MS Valley. This activity will form within a pronounced differential boundary-layer heating/buoyancy gradient amid large MLCAPE of 3000-4000 J/kg in the undisturbed warm sector over the Mid-South. Within a belt of 35-45 kt mid-level west-southwesterlies, initial supercells/clusters congealing into a forward-propagating linear MCS appears probable. Large hail will be possible, mainly early, but the predominant threat should be damaging wind swaths towards the central OH Valley. A couple of embedded tornadoes will also be possible, mainly focused along/just north of the residual outflow boundary arcing west from ongoing convection over central KY. ...Permian Basin... Weak convergence along a convectively enhanced cold front, in combination with a narrow corridor of stronger boundary-layer heating between the front and thicker clouds within the southern-stream closer to the Big Bend, should yield a rather confined corridor of MLCAPE approaching 2500 J/kg in the late afternoon. Deep-layer shear will be modest and convection will probably be slow-moving to the south-southeast but a few severe outflow gusts and isolated large hail will be possible. ...Lee of the central/southern Appalachians... There is some potential for intensification of isolated to scattered storms along residual outflows and a weak surface trough just east of the Blue Ridge, as the low levels warm this afternoon. Mid-level lapse rates will remain weak north of southwest VA, while diffluent mid-level flow in the lee of the central Appalachians will generally hold effective bulk shear below 25 kt north of southwest VA. Localized damaging winds and perhaps marginally severe hail will be the main threats. ...PA/NY... Subtle/embedded perturbations will move over the lower Great Lakes region today, around the southern periphery of the shortwave trough centered on the Ontario-Quebec border. Surface heating in cloud breaks and boundary-layer dew points in the 60s will support MLCAPE of 1000-1500 J/kg east of the influence of the Lower Great Lakes. Mid-level lapse rates will not be steep, but some modest enhancement to mid-upper flow could be sufficient for a few semi-organized clusters capable of producing isolated wind damage for a few hours centered on late afternoon. ...Southern MT to ND... Though forcing for ascent will be weak, at least isolated thunderstorm development will be possible this afternoon/evening from edge of the higher terrain in southern MT northeastward along a weak pre-frontal trough into ND. Surface heating/deep mixing will drive inverted-V profiles with MLCAPE of 500-1500 J/kg. Weak flow supports relatively slow-moving cells/clusters capable of producing isolated strong-severe outflow gusts. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Jul 01 2023 Valid 021200Z - 031200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track. In addition, at least locally Elevated conditions are possible across central and eastern Montana into western North Dakota tomorrow afternoon as a deepening mid-level trough overspreads the northern Rockies. However, fuel receptiveness does not appear robust enough on a widespread basis to warrant Elevated highlights this outlook. ..Squitieri.. 07/01/2023 .PREV DISCUSSION... /ISSUED 0157 AM CDT Sat Jul 01 2023/ ...Synopsis... A mid/upper-level ridge will be centered over the southern Great Basin, supporting a continuation of hot/dry conditions across much of the West. Along the southeastern periphery of the ridge, modest downslope flow off the Mogollon Rim could favor breezy surface winds over parts of southern Arizona -- where a dry/deeply mixed boundary layer (single-digit RH) is expected. Given increasingly dry fuels over the area, locally elevated fire-weather conditions are possible. Farther north, a subtle shortwave impulse will advance southeastward across the northern Great Basin into the central Rockies, aiding in diurnally driven high-based thunderstorms. Deep inverted-V thermodynamic profiles and around 0.4-0.5 inch PW will favor dry thunderstorms capable of isolated lightning-induced ignitions over parts of the Great Basin into the central/southern Rockies. However, marginal fuels over this region cast uncertainty on the overall fire-weather threat -- precluding highlights at this time. ...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 1228 PM CDT Sat Jul 01 2023 Valid 021200Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SUNDAY INTO SUNDAY NIGHT ACROSS MUCH OF TENNESSEE...KENTUCKY...WEST VIRGINIA...VIRGINIA...MARYLAND AND DELAWARE...PARTS OF SOUTHERN OHIO... PENNSYLVANIA AND NEW JERSEY...WESTERN NORTH CAROLINA...NORTHERN GEORGIA...ALABAMA AND MISSISSIPPI...AND EASTERN ARKANSAS... ...SUMMARY... Scattered strong thunderstorms, and a couple of evolving clusters of storms, will pose a risk for severe wind and hail in a corridor from the Mid South and lower Ohio and Tennessee Valley east-northeastward into the Mid Atlantic region Sunday through Sunday night ...Synopsis... Models indicate that split flow across the eastern Pacific into western North America may become more amplified into and through this period. Within this regime, significant cyclogenesis is forecast to proceed later today through Sunday across the Canadian Prairies, with a trailing cold front advancing southeast of the international border, across much of the Northwest and northern Rockies into the northern Great Plains by 12Z Monday. While mid-level ridging builds downstream of the cyclone, across northwestern Ontario, southern Hudson and James Bays into adjacent portions of Quebec, positively tilted mid-level troughing in a branch to the south is forecast to shift slowly east-northeastward across the lower Great Lakes and Ohio Valley. It appears that this will be accompanied by a broad weak surface low, migrating along a diffuse surface frontal zone (initially extending from the northern Mid Atlantic and Ohio Valley into the southern Great Plains), and developing surface troughing to the lee of the Blue Ridge. ...Mid Atlantic/Ohio and Tennessee Valleys into Ark-La-Tex... Along and just south of the weak frontal zone, the boundary-layer may be initially impacted by a considerable amount of remnant convective outflow. How the associated outflow boundaries evolve through midday Sunday remains unclear, but insolation along and to their south likely will contribute to steepening low-level lapse and moderate to large CAPE in the presence of seasonably high moisture content. This appears likely to occur beneath a belt of 30-40+ kt (perhaps stronger where augmented by prior convection) west-southwesterly flow in the 850-500 mb layer, which may prove conducive to renewed strong and organizing convective development Sunday afternoon and evening. Isolated supercell structures are possible initially, posing a risk for severe hail, before potentially damaging wind gusts with evolving clusters becomes the more prominent hazard. ...High Plains... A mid-level perturbation digging within modest to weak northwest flow probably will contribute to scattered thunderstorm development to the lee of the southern Rockies Sunday afternoon and evening. Aided mostly by steep lower/mid-tropospheric lapse rates, a couple of storms may pose a risk for severe hail and wind. ...North Dakota/Minnesota... Large mixed-layer CAPE may develop within pre-frontal surface troughing near the state border vicinity by late Sunday afternoon. However, stronger mid/upper forcing for ascent and shear may remain mostly displaced to the north of the international border, resulting in mainly highly conditional severe weather potential for this period. ...Southern Montana... Moistening post-frontal upslope flow might contribute to sufficient destabilization to support isolated supercell development to the north of the Big Horn Basin, perhaps aided by large-scale forcing for ascent associated with warm advection late Sunday afternoon and evening. ..Kerr.. 07/01/2023 Read more

WW 0423 Status Updates
STATUS REPORT ON WW 423 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..06/30/23 ATTN...WFO...PAH...LSX... STATUS REPORT FOR WS 423 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC003-005-013-027-055-059-065-069-077-081-083-087-119-121-127- 133-145-151-153-157-163-165-181-189-191-193-199-302340- IL . ILLINOIS COUNTIES INCLUDED ARE ALEXANDER BOND CALHOUN CLINTON FRANKLIN GALLATIN HAMILTON HARDIN JACKSON JEFFERSON JERSEY JOHNSON MADISON MARION MASSAC MONROE PERRY POPE PULASKI RANDOLPH ST. CLAIR SALINE UNION WASHINGTON WAYNE WHITE WILLIAMSON INC129-147-163-173-302340- IN . INDIANA COUNTIES INCLUDED ARE POSEY SPENCER VANDERBURGH WARRICK Read more

WW 423 SEVERE TSTM IL IN KY MO 302050Z - 010400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 423 NWS Storm Prediction Center Norman OK 350 PM CDT Fri Jun 30 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Illinois Southwest Indiana Western Kentucky East-central to southeast Missouri * Effective this Friday afternoon and evening from 350 PM until 1100 PM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 80 mph possible Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible SUMMARY...Multiple multicell clusters with transient supercell structures will likely develop into the early evening. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 50 miles north northwest of Vichy MO to 35 miles north northeast of Fort Campbell KY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 422... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 70 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 29025. ...Grams Read more

WW 0422 Status Updates
STATUS REPORT ON WW 422 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..06/30/23 ATTN...WFO...PUB...GLD...BOU...ABQ... STATUS REPORT FOR WS 422 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC009-011-017-025-039-041-055-061-063-071-073-089-099-101-121- 125-302340- CO . COLORADO COUNTIES INCLUDED ARE BACA BENT CHEYENNE CROWLEY ELBERT EL PASO HUERFANO KIOWA KIT CARSON LAS ANIMAS LINCOLN OTERO PROWERS PUEBLO WASHINGTON YUMA KSC023-039-063-065-071-109-137-153-179-181-193-199-203-302340- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GOVE GRAHAM GREELEY LOGAN NORTON RAWLINS SHERIDAN SHERMAN THOMAS WALLACE WICHITA Read more

WW 422 SEVERE TSTM CO KS NE NM 301855Z - 010100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 422 NWS Storm Prediction Center Norman OK 1255 PM MDT Fri Jun 30 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Colorado Northwest Kansas Far southwest Nebraska Far northeast New Mexico * Effective this Friday afternoon and evening from 1255 PM until 700 PM MDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible A tornado or two possible SUMMARY...A few supercells should develop over east-central Colorado and off the Sangre de Cristo mountains before growing upscale into an eastward-moving cluster towards northwest Kansas. The severe thunderstorm watch area is approximately along and 70 statute miles east and west of a line from 60 miles north northwest of Goodland KS to 25 miles east southeast of Raton NM. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25030. ...Grams Read more

WW 0424 Status Updates
STATUS FOR WATCH 0424 HAS NOT BEEN ISSUED YET Read more

WW 424 SEVERE TSTM KS MO 302215Z - 010400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 424 NWS Storm Prediction Center Norman OK 515 PM CDT Fri Jun 30 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Kansas Western Missouri * Effective this Friday afternoon and evening from 515 PM until 1100 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Isolated thunderstorms are expected to develop along a boundary from eastern Kansas into western Missouri. High instability and sufficiently strong winds aloft will pose a risk of large hail and damaging wind gusts in the strongest cells. The severe thunderstorm watch area is approximately along and 35 statute miles north and south of a line from 35 miles west of Manhattan KS to 15 miles north of Columbia MO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 422...WW 423... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27025. ...Hart Read more

MD 1359 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHEAST KANSAS/NORTHERN MISSOURI
Mesoscale Discussion 1359 NWS Storm Prediction Center Norman OK 0427 PM CDT Fri Jun 30 2023 Areas affected...Northeast Kansas/Northern Missouri Concerning...Severe potential...Watch possible Valid 302127Z - 302300Z Probability of Watch Issuance...60 percent SUMMARY...Severe thunderstorm potential should steadily increase through late afternoon across east-central/northeast Kansas into northern Missouri. A Watch may be needed. DISCUSSION...Latest visible satellite imagery shows deepening/towering cu in vicinity of the roughly WSW/ENE-oriented boundary across central/northeast Kansas and northern Missouri. Hot temperatures and prevalent low/some middle 70s F surface dewpoints are contributing to minimal inhibition with MLCAPE estimated as high as 3000-4000 J/kg as per latest mesoanalysis and modifications to the 19z KTOP observed sounding. Moderately strong west-southwesterlies mid/high-level flow overlies the frontal zone, and as such, wind profiles will support some initial supercells capable of large hail. The potential for damaging winds are likely to increase this evening as cell mergers occur. ..Guyer/Hart.. 06/30/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...SGF...EAX...TOP...ICT... LAT...LON 39339772 39839565 39829287 39149195 38469227 38679417 38659593 38219715 38149802 39339772 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0244 PM CDT Fri Jun 30 2023 Valid 302000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN AND CENTRAL HIGH PLAINS EASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Scattered damaging winds and large hail, along with a couple tornadoes will be possible into this evening from the Mid-Mississippi to Tennessee Valleys and across the central to southern High Plains. ...20Z Update... Much of the previous forecast remains on track, with severe hail and wind producing storms most likely to develop around the periphery of the upper ridge (centered over the southern Plains) this afternoon into tonight. One main change to this outlook was to expand tornado probabilities in area across western Kansas. At least a couple of landspout tornadoes have already occurred over central CO with storms aided by the ascent of a passing mid-level impulse. Additional storm development into KS is likely along a baroclinic zone, where a few additional tornadoes (likely landspouts in nature) may occur later this afternoon. However, any tornado potential that becomes realized should be brief since upscale growth into one or more MCSs should follow only a few hours after convective initiation. The second change made to the outlook was to expand the 5 and 15 percent wind probabilities ahead of a persistent damaging-gust producing MCS along the AL/GA border, where additional damaging gusts are possible through the afternoon. Please see MCD 1356 for more details. ..Squitieri.. 06/30/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Jun 30 2023/ ...Mid-MS to the TN Valley... The composite outflow from yesterday's MCS is still fairly well defined from near I-70 in MO southeastward into western KY, with a relatively cooler air mass farther northeast. Elevated storm clusters are ongoing within two weakening warm theta-e advection regimes, one across west-central IL and the other near the GA/TN/AL border area. Neither regime is expected to greatly intensify as activity loosely parallels the more pronounced CAPE gradients to their south and west, respectively. Later this afternoon into early evening, it appears the primary focus for at least isolated thunderstorm development will be along the composite outflow boundary, but with uncertainty on exactly where. Vertical shear will be on the lower margins for sustained supercells, though continuing steep mid-level lapse rates and large to extreme buoyancy will favor a cluster or two capable of producing locally significant damaging wind and hail. There is uncertainty regarding whether or not broader upscale growth will evolve and persist into tonight given relatively weak low-level flow, and how far east/southeast any such cluster could move with an attendant threat for damaging winds. ...Central/southern High Plains... A lower-amplitude shortwave trough will move eastward from the central Rockies to the central Great Plains through tonight. 50s surface dew points across eastern CO within a post-frontal environment, steep mid-level lapse rates, and strong surface heating in cloud breaks will result in moderate buoyancy with MLCAPE of 1000-2000 J/kg. Thunderstorm coverage will increase this afternoon just east of the Front Range and over the Raton Mesa, and storms will subsequently spread east across the High Plains. Effective bulk shear of 40-45 kts with relatively straight hodographs will initially support a few supercells capable of producing significant severe hail and perhaps a couple tornadoes, especially over east-central CO. Upscale growth into clusters/line segments appears likely by late afternoon. The potential for occasional severe outflow gusts/isolated large hail will persist through this evening as storms spread eastward into KS/southern NE. Farther south, a weak surface trough/dryline will focus scattered thunderstorm development this afternoon across the southern High Plains. Deep-layer vertical shear will weaken gradually with southward extent, but be sufficient to support a mix of multicell clusters and transient supercells capable of producing isolated strong-severe outflow gusts and large hail later this afternoon into the evening. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Fri Jun 30 2023 Valid 011200Z - 021200Z ...NO CRITICAL AREAS... No major changes are needed to the outlook. Stronger flow aloft should lead to downslope winds in the lee of the Cascades in southeastern Washington, with afternoon RH near 10-15% and breezy surface winds. However, fuels in the area are marginal at best, and any elevated fire weather conditions are expected to be localized. Therefore, an Elevated area is not justified at this time. ..Supinie.. 06/30/2023 .PREV DISCUSSION... /ISSUED 0157 AM CDT Fri Jun 30 2023/ ...Synopsis... Along the northern periphery of a large-scale ridge centered over the West, a westerly midlevel speed maximum will translate eastward across British Columbia into Alberta during the day. Along the southern periphery of this feature, around 40 kt of 500-mb flow will cross the Cascades, promoting breezy surface winds along the eastern slopes in Washington. These winds, coupled with downslope-related RH reductions (around 15 percent minimum RH), could yield locally elevated fire-weather conditions -- especially in the Cascade gaps. However, the combination of marginal fuels and the localized nature of the threat preclude Elevated highlights at this time. ...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 1228 PM CDT Fri Jun 30 2023 Valid 011200Z - 021200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN MISSOURI...CENTRAL AND SOUTHERN ILLINOIS...WESTERN INDIANA AND WESTERN KENTUCKY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE MID-MISSISSIPPI VALLEY TOWARD THE CENTRAL APPALACHIANS...AND PARTS OF FAR SOUTHEAST NEW MEXICO INTO SOUTHWEST TEXAS... ...SUMMARY... Severe thunderstorms will be possible tomorrow/Saturday, from the central and southern Appalachians region westward through the Ohio/Tennessee Valleys into the mid-Mississippi Valley. Severe winds are the greatest concern, especially from eastern Missouri into western Indiana. ...Synopsis... A mid-level trough will traverse the central MS Valley region as a second upper trough grazes the northwestern CONUS tomorrow (Saturday). Ahead of the MS Valley mid-level trough, abundant low-level moisture will be in place from the MS River to the Atlantic Coast, fostering scattered to widespread thunderstorm potential. Storms from today (Day 1) should be ongoing at the start of Day 2 (Saturday) from the Plains into the OH Valley. Deep-layer ascent associated with the progressing mid-level trough over the Midwest, as well as low-level convergence along a trailing cold front across the Southern Plains, will foster an increase in convective coverage and intensity through the day, with severe storms possible, especially across the Mid-MS Valley. ...Mid-MS Valley to the central Appalachians... A complex severe weather scenario is expected to unfold across the Midwest into the OH/TN Valley areas tomorrow, with later day activity predicated on earlier day storms. At least scattered thunderstorms (perhaps in the form of organized multicells/MCSs) should be ongoing at the start of the period from the Midwest and points east. Despite the variability in potential placement and timing of earlier convection and subsequent impact on boundary-layer modification, the latest guidance has come to a consensus that an organized round of severe storms should occur from the mid-MS valley and points east during the afternoon hours. Along the periphery of the upper ridge, the embedded mid-level trough should support convective initiation to the west of the MS river by afternoon, where 70+ F surface dewpoints are overspread by 8 C/km mid-level lapse rates, resulting in 2000-3000 J/kg MUCAPE. Strong speed shear with height will support elongated hodographs and in turn, thunderstorm organization. Much of the latest convection-allowing guidance portrays MCS development, with the potential for severe winds, occasional bouts of large hail, and perhaps a tornado or two. The MCS should form in MO by early afternoon and progress eastward toward the Appalachians by early evening, where Category 2/Slight Risk probabilities are in place. A Category 3/Enhanced Risk also exists from the eastern MO into western IN/KY, where confidence is highest in a relatively greater concentration of severe gusts occurring during the mature stage of the forecast MCS. ...Portions of the Hudson Valley... Ahead of a surface lee trough, diurnal heating of a moist low-level airmass will promote enough boundary layer destabilization to support convective initiation across the Hudson Valley into the central Appalachians during the late morning/early afternoon hours. Given relatively poor mid-level lapse rates, tall and thin CAPE profiles will promote enough buoyancy for strong but brief pulse cellular convection and perhaps multicells when factoring in mediocre vertical shear profiles. The strongest storms may produce isolated severe wind/hail during the afternoon/evening hours, warranting the maintenance of Category 1/Marginal Risk probabilities this outlook. ...Southern Plains into the southern High Plains... Thunderstorms may be ongoing at the start of the period across the Southern Plains near the southward-sagging cold front. Through the day, surface heating will destabilize the boundary layer as 7-8 C/km mid-level lapse rates overspread mid to upper 60s F surface dewpoints. 1000-2000 J/kg SBCAPE should manifest across the southern Plains, with over 3000 J/kg SBCAPE possible closer to the Trans Pecos in southwest TX. Vertical shear magnitudes should be modest at best (generally under 30 kts of effective bulk shear). However, elongated hodographs suggest that relatively robust multicellular convection may initiate by afternoon, both along the cold front in central OK into western TX, and along a dryline in western TX. Severe wind/hail may accompany the more intense multicell clusters that form, with the best chance for severe occurring across far southeast NM into southwest TX, where a Category 2/Slight Risk has been introduced. ..Squitieri.. 06/30/2023 Read more

MD 1344 CONCERNING SEVERE THUNDERSTORM WATCH 418... FOR PARTS OF NORTHERN ALABAMA
Mesoscale Discussion 1344 NWS Storm Prediction Center Norman OK 0515 PM CDT Thu Jun 29 2023 Areas affected...Parts of northern Alabama Concerning...Severe Thunderstorm Watch 418... Valid 292215Z - 292345Z The severe weather threat for Severe Thunderstorm Watch 418 continues. SUMMARY...Large hail and damaging winds remain possible with a southward-moving supercell cluster in northern Alabama this evening. It is unclear if a small downstream watch will be needed, though trends are being monitored. DISCUSSION...Latest regional radar data shows a southward-advancing supercell cluster in northern Alabama this evening, which is tracking along the eastern edge of a strongly unstable surface-based air mass. In the short-term, large hail (possibly to 2 inches in diameter) and damaging winds remain possible with this activity. Within the pre-convective environment, a moist and well-mixed boundary layer (evident via surface obs and HCRs in visible satellite imagery) could support the maintenance of this supercell cluster with southward extent, before the onset of increasing nocturnal static stability. Modest deep-layer flow/shear limits confidence in how long lived convection will be this evening, or how large of an area will be affected. Trends are being monitored for a new watch downstream of Severe Thunderstorm Watch 418. ..Weinman/Hart.. 06/29/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BMX...HUN... LAT...LON 34068790 34438786 34668772 34738753 34728705 34588678 34368665 33928662 33548690 33558740 33718774 34068790 Read more

MD 1343 CONCERNING TORNADO WATCH 419... FOR PORTIONS OF SOUTHEAST WYOMING INTO NORTHEAST COLORADO AND THE NEBRASKA PANHANDLE
Mesoscale Discussion 1343 NWS Storm Prediction Center Norman OK 0512 PM CDT Thu Jun 29 2023 Areas affected...portions of southeast Wyoming into northeast Colorado and the Nebraska Panhandle Concerning...Tornado Watch 419... Valid 292212Z - 292345Z The severe weather threat for Tornado Watch 419 continues. SUMMARY...The severe threat continues across Tornado Watch 419. Very large hail remains a concerns and an isolated tornado is still possible over the next few hours. Storms may eventually congeal into one or more MCSs with a severe wind threat later this evening. DISCUSSION...Multiple multicellular clusters and supercells continue to progress eastward across eastern WY and the Denver Metropolitan area, with a history of severe hail. MRMS mosaic radar imagery shows these storms continuing to build in intensity, with 50 dBZ echoes approaching 40 kft with some of the supercell structures. 8+ C/km surface-500 mb lapse rates atop mid 50s F surface dewpoints are contributing to 2000+ J/kg MLCAPE ahead of the ongoing storms, where RAP forecast soundings also show elongated hodographs and 50+ kts of effective bulk shear. As such, the stronger multicells and supercells should continue to pose a large hail threat, with 2+ inch diameter stones possible with the stronger, longer-lived supercells. Low-level shear is relatively weak across the central High Plains, with ongoing supercells showing outflow tendencies. However, a tornado or two still cannot be ruled out, especially over southeast Wyoming. Here, enhanced upslope flow and relatively higher 0-3 km CAPE may enhance tilting/stretching potential if a storm can become inflow-dominant. Nonetheless, storm outflows should support multicellular mergers later this evening, especially in/near the Nebraska Panhandle. Should this occur, severe gusts could become more prevalent. ..Squitieri.. 06/29/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GLD...BOU...CYS... LAT...LON 39390516 41390531 42590483 42940415 42860320 41980284 40920270 39990270 39330329 39160420 39390516 Read more

WW 0420 Status Updates
STATUS REPORT ON WW 420 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SSW BMG TO 15 N SDF TO 25 SE LUK. ..THORNTON..06/29/23 ATTN...WFO...PAH...LMK...ILN... STATUS REPORT FOR WS 420 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC059-069-151-165-199-292240- IL . ILLINOIS COUNTIES INCLUDED ARE GALLATIN HARDIN POPE SALINE WILLIAMSON INC043-061-292240- IN . INDIANA COUNTIES INCLUDED ARE FLOYD HARRISON KYC001-003-005-009-021-027-029-031-033-047-055-057-059-061-067- 073-085-087-091-093-097-099-101-103-107-111-113-123-139-141-143- 149-155-163-167-169-171-177-179-183-185-187-191-209-211-213-215- 217-219-221-225-227-229-233-239-292240- KY . KENTUCKY COUNTIES INCLUDED ARE Read more

WW 420 SEVERE TSTM IL IN KY OH 292015Z - 300100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 420 NWS Storm Prediction Center Norman OK 415 PM EDT Thu Jun 29 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Illinois Southern Indiana Kentucky Southwest Ohio * Effective this Thursday afternoon and evening from 415 PM until 900 PM EDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A well-organized/previously intense squall line may largely continue to gradually weaken, but nonetheless pose a risk for severe-caliber wind gusts this afternoon as it progresses generally southeastward. The severe thunderstorm watch area is approximately along and 50 statute miles north and south of a line from 35 miles north northeast of Lexington KY to 10 miles west northwest of Paducah KY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 415...WW 416...WW 417...WW 418...WW 419... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 33040. ...Guyer Read more

WW 0419 Status Updates
STATUS REPORT ON WW 419 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..06/29/23 ATTN...WFO...BOU...CYS... STATUS REPORT FOR WT 419 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC001-005-013-014-031-035-039-059-069-075-087-121-123-292240- CO . COLORADO COUNTIES INCLUDED ARE ADAMS ARAPAHOE BOULDER BROOMFIELD DENVER DOUGLAS ELBERT JEFFERSON LARIMER LOGAN MORGAN WASHINGTON WELD NEC007-013-033-045-105-123-157-165-292240- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES KIMBALL MORRILL SCOTTS BLUFF SIOUX WYC001-009-015-021-027-031-292240- WY . WYOMING COUNTIES INCLUDED ARE Read more

WW 419 TORNADO CO NE WY 291915Z - 300300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 419 NWS Storm Prediction Center Norman OK 115 PM MDT Thu Jun 29 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Northern Colorado Nebraska Panhandle Southeast Wyoming * Effective this Thursday afternoon and evening from 115 PM until 900 PM MDT. * Primary threats include... A couple tornadoes possible Scattered large hail likely with isolated very large hail events to 3.5 inches in diameter possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Severe storms including supercells are expected to develop near the foothills and adjacent High Plains through the afternoon. Very large hail is possible, along with the potential for tornadoes. The storms will persist generally eastward into the Nebraska Panhandle and northeast Colorado plains this evening. The tornado watch area is approximately along and 75 statute miles east and west of a line from 50 miles east northeast of Douglas WY to 45 miles southeast of Denver CO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). 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 415...WW 416...WW 417...WW 418... 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 550. Mean storm motion vector 26025. ...Guyer Read more