Administrators NorthGeorgiaWX Posted August 1 Administrators Posted August 1 SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Thu Aug 01 2024 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MOST OF KENTUCKY INTO OHIO...AND OVER PARTS OF INDIANA AND WEST VIRGINIA... ...SUMMARY... Severe thunderstorms remain possible today across parts of the Midwest and Ohio Valley, with the primary threat being damaging winds. ...20Z Update... Minor changes were made to the existing outlook primarily behind the ongoing severe MCS now over southern IN and into far northern KY. A moist and unstable air mass remains downstream of this system, and the potential remains for north and/or southward growth as the cold pool increases. In addition, storms may develop into OH ahead of the main system, with localized downbursts possible. For more information see mesoscale discussion 1788. To the north, an unstable air mass has developed over WI, with scattered cells noted. Shear will remain weak, but continued heating beneath the cool upper trough may support isolated severe storms with wind and/or hail. Some of this activity may persist into the evening into northern IL and IN. With time, severity is expected to decrease. For more information see mesoscale discussion 1787. Elsewhere, a band of strong instability continues to develop in an east-west oriented zone near a weak front extending from the TX Panhandle toward the Ozarks. Isolated storms are expected later today, but the severe threat should remain localized. Although lift is very weak, any cells that develop will have severe gust or brief hail potential. ..Jewell.. 08/01/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Aug 01 2024/ ...Upper Midwest/Ohio Valley... Primary upper trough located over the Upper Midwest late this morning is forecast to develop generally east-southeastward across the Great Lakes and OH Valley through the period. Multiple convectively enhanced MCVs are present over the Midwest, along with outflow boundaries from prior convection. These features will likely serve as forcing mechanisms for additional robust thunderstorm development across the OH Valley this afternoon and evening. One such MCV located over far eastern MO into western IL should track eastward through the day, while aiding a cluster of thunderstorms that have already started strengthening across southern IL. The outflow boundary extending across southern IN and vicinity will likely serve as a focus for the subsequent MCS track, as the airmass along/south of this boundary is rapidly destabilizing. Given the mainly linear mode expected and sufficient deep-layer shear present, scattered severe/damaging winds should be the main threat. But, a line-embedded tornado or two may also occur, especially near the outflow boundary. See recently issued Mesoscale Discussion 1784 for more details. The northward extent of MCS development into northern/central IN/OH remains uncertain given lingering cloudiness and the outflow boundary remaining farther south. Still, there may be additional strong to severe thunderstorm development across these areas in association with another MCV over northeast IL/northwest IN. Have therefore made no changes to the northern edge of the Slight Risk in the OH Valley with this update. Farther northwest, a separate area of strong to locally severe thunderstorm development may occur closer to the mid/upper-level cyclone across parts of WI into northern IL. Deep-layer shear is forecast to remain modest, but moderate instability could support isolated hail and damaging wind with the strongest cores. ...Mid-Atlantic into the Carolinas and Southeast... Strong heating of a moist environment will result in the development of moderate to locally strong instability from GA and the Carolinas into southern parts of the Mid-Atlantic. Large-scale ascent across this region should remain rather weak/nebulous. Accordingly, thunderstorm coverage remains uncertain, and could be isolated to widely scattered. However, robust thunderstorms may still form by late afternoon into early evening, as lingering convective inhibition erodes. Modest mid-level northwesterly flow in the wake of the departing upper-level trough along the East Coast may provide sufficient effective bulk shear for modest updraft organization, with a threat of isolated damaging winds and perhaps marginally severe hail. ...Southern/Central High Plains to the Mid-South... The outflow-reinforced front has nearly stalled over the south-central High Plains into northeast NM. Initial development may occur near the Raton Mesa NM vicinity in a modest low-level upslope flow regime, with more isolated development possible farther east along the front into the OK/TX Panhandles, and potentially farther east along the boundary into northern OK/AR and southern MO. Low/midlevel flow will remain rather weak. Still, sufficient veering of winds with height should support effective shear generally around 20-30 kt. This should be sufficient for some convective organization with of moderate to strong instability present along/near the boundary. Initially discrete thunderstorms could produce large hail, but outflow and convective consolidation/clustering with the well-mixed boundary layer should lead to an increasing threat for isolated severe gusts later in the convective evolution. Read more View the full article Quote
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