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    • SPC 1730Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri Apr 26 2024 Valid 271200Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Numerous severe thunderstorms are likely Saturday into Saturday night. The greatest severe threat is currently anticipated across parts of the central and southern Plains, where very large hail, damaging winds, and multiple strong tornadoes will be possible. A broader area of potential threat will extend from south-central Texas north-northeastward to the Great Lakes. ...Synopsis... A shortwave trough over the Upper Midwest Saturday morning should further de-amplify as it moves across the Great Lakes through the day in tandem with a weakening surface low. A large-scale upper trough over the Southwest will eject across the southern/central Plains through the period, while an attendant 50-70 kt southwesterly mid-level jet overspreads these same regions. At the surface, lee cyclogenesis is expected to occur over western KS through Saturday afternoon, before the low eventually develops towards central KS Saturday night. A dryline will extend southward from this low across the southern/central High Plains, and a warm front will extend northeastward from the low across the central Plains into the Upper Midwest. ...Southern/Central Plains... Most guidance develops thunderstorms early Saturday morning across northwest TX into central OK. This activity will likely be related to a subtle mid-level shortwave trough ejecting northeastward across the southern High Plains, along with ascent along a westward retreating dryline and warm/moist advection attendant to a southerly low-level jet. Steep lapse rates aloft fostering moderate to strong MUCAPE, along with sufficient deep-layer shear, should support some large hail threat with this early day convection. The potential for these morning thunderstorms to continue into the afternoon across central/eastern OK and eastern KS remains uncertain. Even so, some severe threat may persist with this activity as it spreads eastward. Fairly meridional flow at low/mid levels suggests a messy mode may develop, with numerous thunderstorm mergers/interactions possible. In the wake of this activity, it still appears likely that substantial destabilization will occur along/east of the dryline and south of the warm front, with daytime heating of a moist low-level airmass supporting MLCAPE of 2000-3500 J/kg from north-central KS southward into parts of western OK and northwest TX. As ascent with the ejecting upper trough overspreads this warm sector, multiple attempts at supercell development will likely occur both along the dryline and warm front, as 40-50 kt of deep-layer shear promotes robust thunderstorm organization. Any supercells that can form and persist will be capable of producing very large hail in excess of 2 inches in diameter. With time Saturday evening, a steadily strengthening low-level jet will foster increased low-level shear, and greater tornado potential. Multiple strong tornadoes appear possible during the late afternoon to early evening time frame, as effective SRH of 150-250+ m2/s2 supports low-level updraft rotation. Locally greater low-level shear will probably be realized along/near the warm front Saturday evening, and the Enhanced Risk has been expanded slightly northward to include more of south-central/southeast NE. It remains unclear how long a discrete mode will be able to be maintained, as a tendency for convection to grow upscale into one or more bowing clusters appears likely Saturday evening/night. As this mode transition occurs and convection spreads eastward, a greater threat for severe/damaging winds will probably be realized across the southern/central Plains. Due to the influence of the morning convection and potential for messy storm modes/convective evolution Saturday afternoon, confidence was not high enough to include greater tornado and/or hail probabilities across the southern/central Plains at this time. ...Northwest Kansas into Southwest Nebraska and Northeast Colorado... Low-level easterly flow will maintain modest low-level moisture within the post-frontal regime from northwest KS/southwest NE into northeast CO. Steep midlevel lapse rates will support MLCAPE increasing to around 500 J/kg, with veering wind profiles with height through mid levels supporting some potential for organized convection. A supercell or two could evolve within this regime, with an attendant threat of large hail and possibly a tornado. ...Upper Midwest/Great Lakes... A mostly separate regime of at least isolated severe thunderstorm potential remains evident along/ahead of the front from eastern IA into parts of the Great Lakes region. While the influence of the weakening shortwave trough initially over the Upper Great Lakes may remain mostly displaced to the north of the warm sector, diurnal heating/destabilization and gradually lessening convective inhibition may support isolated storm development by late afternoon along the front. Deep-layer shear will remain sufficient for updraft organization, supporting a potential for supercells and/or stronger clusters capable of producing severe hail, damaging gusts, and possibly a tornado or two. Some increase in storm coverage will be possible into the evening as the cold front moves southeastward. Thunderstorms should weaken overnight across this region, though a stronger cluster to two could move from eastern portions of the central Plains toward the upper MS Valley before the end of the forecast period. ..Gleason.. 04/26/2024 Read more View the full article
    • MD 0526 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY FOR PARTS OF CENTRAL AND EASTERN NEBRASKA ...NORTHEAST KANSAS INTO SOUTHWESTERN IOWA. Mesoscale Discussion 0526 NWS Storm Prediction Center Norman OK 1221 PM CDT Fri Apr 26 2024 Areas affected...parts of central and eastern Nebraska ...northeast Kansas into southwestern Iowa. Concerning...Severe potential...Tornado Watch likely Valid 261721Z - 261815Z Probability of Watch Issuance...95 percent SUMMARY...Scattered storm development appears likely on the dryline within central and eastern Nebraska early this afternoon. Supercells with large to very large hail and tornadoes are possible. A Tornado Watch is likely needed. DISCUSSION...Rapid destabilization is ongoing within the dry slot ahead of an upper trough moving into the central Plains. Visible imagery shows towering cumulus deepening along the bent back dryline from near Kearney, NE to the KS border. A pocket of low to mid 60s F surface dewpoints has remained sheltered from deeper vertical mixing due to lingering clouds near the surface low. As cloud breaks enlarge with the advection of dry mid-level air, insolation will support the removal of remaining MLCINH through the early afternoon. Area model sounding show 1500-2000 J/kg of MLCAPE with strongly veering wind profiles and 40-45 kt of effective shear. As large-scale ascent moves over early this afternoon, scattered supercell development is expected along the dryline. Hi-res guidance and observational trends are in good agreement that an arc of storms could develop as early as 18-19z and spread northeastward into east eastern NE and eventually western IA. With backed low-level flow near the low/warm front and strongly veering wind profiles overlapping with large low-level buoyancy, supercells appear likely to pose a risk for tornadoes (possibly significant) in addition to large to very large hail. The southern and eastern extent of the threat remains somewhat uncertain as cloud debris and outflow from the morning convection are still in place. Still, gradual destabilization is likely this afternoon as ascent and clearing arrive from the west. A tornado watch will likely be needed early this afternoon. ..Lyons/Hart.. 04/26/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...EAX...FSD...OAX...TOP...GID...LBF... LAT...LON 42649674 42299596 41909541 41399524 40729519 40129527 39949546 39889575 39859598 39829630 39859679 39889720 39979749 40089770 40329792 40639812 40869834 40979860 41019894 41179902 41629913 42149910 42239906 42579833 42739771 42749712 42649674 Read more View the full article
    • SPC 1630Z Day 1 Outlook Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1142 AM CDT Fri Apr 26 2024 Valid 261630Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM EASTERN NEBRASKA/WESTERN IOWA SOUTHWARD TO EASTERN OKLAHOMA AND NORTHEAST TEXAS... CORRECTED FOR WEB GRAPHICS ERROR ...SUMMARY... A few tornadoes, including a couple of strong tornadoes, isolated very large hail (greater than 2 inch diameter) and isolated wind damage will be possible, mainly this afternoon/evening from northeast Kansas/southeast Nebraska into western Missouri, eastern Oklahoma, western Arkansas, and northeast Texas. ...NE/IA/MO/KS... Water vapor loop shows a strong shortwave trough rotating across KS/NE. A deep surface low is analyzed ahead of this trough over central NE, with a dryline extending southward into central KS. A corridor of ample low-level moisture is present ahead of the dryline over southeast NE/northeast KS, where daytime heating will lead to moderate MLCAPE values and rapid thunderstorm development by mid-afternoon. Backed low-level winds and favorable shear profiles will promote supercells in the bent-back region of the low, with very large hail and tornadoes possible. These storms will progress eastward into western IA and northwest MO through the early evening. A strong tornado or two is possible in this region. ...OK/MO/AR... A large nocturnal MCS that affected much of OK has quickly weakened and departed, with rapid northward return of low-level moisture occurring in the wake of the system. By mid-afternoon, mid-upper 60s dewpoints are expected along the dryline over east-central OK. Forecast soundings show very steep mid-level lapse rates and favorable shear profiles to promote discrete supercells capable of all severe hazards, including very large hail and strong tornadoes. Storms will track northeastward into southwest MO and northwest AR this evening. CAM guidance varies on coverage of storms, but parameters appear quite strong and warrant an upgrade to ENH given the conditional risk of significant severe weather. ...Northeast TX... A third area of significant risk of severe storms lies across parts of northeast and east-central TX today. A cluster of severe/supercell storms has formed this morning to the west of Waco, TX. These storms are expected to increase in coverage through the afternoon and develop eastward across much of northeast TX. Forecast soundings show a very moist and unstable environment, with sufficient low-level and deep-layer shear for persistent supercell structures and risks of a few tornadoes and very large hail. Given the number of storms and the favorable environment, have also upgraded this narrow corridor to ENH. ..Hart.. 04/26/2024 Read more View the full article
    • WW 0139 Status Updates STATUS FOR WATCH 0139 HAS NOT BEEN ISSUED YET Read more View the full article
    • WW 0139 Status Updates STATUS FOR WATCH 0139 HAS NOT BEEN ISSUED YET Read more View the full article
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