7AM Day 1 Convective Outlook for Thursday, March 5. THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE EASTERN TEXAS PANHANDLE INTO WESTERN OKLAHOMA
SUMMARY
Scattered severe thunderstorms are expected late this afternoon into tonight from northwest Texas and the Texas Panhandle into western Oklahoma and southern/central Kansas. Large to very large hail, a few tornadoes, and severe/damaging winds will all be possible within this corridor.
Southern/Central Plains
An upper trough will amplify over the western U.S. today as a broad zone of modestly enhanced mid-level southwesterly flow persists over the southern/central Plains. At the surface, lee cyclogenesis is forecast to occur across eastern CO through this evening, which will promote continued northward transport of low-level moisture across TX into OK/KS. A surface dryline will also extend southward from the low over the southern High Plains. Daytime heating of this moist airmass and the presence of steep mid-level lapse rates will support the development of at least 1000-1500 J/kg of MLCAPE by late afternoon along/east of the dryline. Most guidance continues to suggest that convective temperatures will be reached by 21-23Z across the southern High Plains.
While large-scale ascent will remain fairly nebulous, current expectations are for increasing low-level convergence along the dryline and a strengthening southerly low-level jet to encourage convective initiation across the eastern TX Panhandle and vicinity. Forecast deep-layer shear around 40 kt will easily support supercells with an associated threat for large to very large hail initially (potentially up to 2-3 inches in diameter). Increasing low-level shear through the evening will also foster enlarged low-level hodographs and the potential for a few tornadoes with this activity. With time this evening, convection is forecast to grow upscale into a small but potentially intense cluster as it moves northeastward into parts of western/northern OK and southern/central KS.
Isolated severe hail may occur tonight with elevated convection farther north in a low-level warm advection regime across eastern NE/ northwest MO into IA. Farther south, isolated supercells may also occur along the length of the dryline across west TX late this afternoon/evening, with associated threat for occasional large hail and severe gusts. However, confidence in any more than isolated coverage remains low due to weak large-scale forcing.
Ohio Valley into the central Appalachians
A mid-level shortwave trough will move quickly eastward today across the OH Valley. Modest low-level moisture will remain in place along/south of a front, with generally weak instability forecast across the warm sector. Even so, sufficiently strong low to mid-level winds associated with this shortwave trough may promote occasional damaging winds with loosely organized clusters that can develop and spread eastward through the afternoon.
Florida Peninsula
Beneath an upper high and within an easterly low-level flow regime, strong heating will occur today across the FL Peninsula, with dewpoints dropping into the mid 60s F. Despite the upper high, mid-level temperatures will remain relatively cool. Scattered convection appear probable along the western FL Peninsula during the afternoon where low-level convergence will be maximized. Locally strong wind gusts will be possible, though organized severe thunderstorms are not forecast owing to weak deep-layer shear.