1PM 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 are possible.
20z Update
No changes have been made to the D1 Convective Outlook with this update.
Visible satellite continues to show continued mid-level cloud cover across the far eastern Texas Panhandle into central Oklahoma. A warm front has shifted northward across central Oklahoma, with 60F dew points as far north as a line from the Oklahoma City Metro to Tulsa and northeast OK. Dew points in the Texas Panhandle are also slowly increasing, with mid to upper 50s. Breaks in the clouds are increasing across this region, with filtered heating and temperatures warming into the mid 60s to 70s on the western edge of the cloud cover. Cu development is noted across the dryline in far western TX/eastern NM. Steady cumulus development is ongoing across the southern Texas Panhandle into western OK, with billow clouds downstream of Cap Rock from Motley, Childress, and Cottle Counties indicative of continued low-level stability, which is noted in the 18z sounding from AMA.
Thunderstorm development is expected near/just east of the Caprock Escarpment with a few more hours of additional daytime heating by late afternoon (4-6 PM CST as mentioned below). Initial development is expected to be supercelluar, with potential for large to very large hail. Strengthening of the low-level jet and resulting increase in low-level shear through the evening will enlarge hodographs, with an increasing risk for tornadoes, with potential of a strong tornado (EF2+).
Additional thunderstorm development may also occur across the length of the dryline into west Texas where a Marginal Risk was maintained. A Marginal Risk also continues across the Ohio Valley. See previous discussion below for more information.
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 Colorado through this evening, which will promote continued northward transport of low-level moisture across Texas into Oklahoma/Kansas. A surface dryline will also extend southward from the low over the southern High Plains.
Multi-layer cloud cover remains semi-prevalent at late morning but peripheral gradual clearing is noted across parts of western North Texas as well as along the New Mexico/Texas border vicinity. The strongest heating/mixing will occur in vicinity across far west/northwest Texas, but it seems probable that storm development will occur within the somewhat richer moisture near/just east of the Caprock Escarpment including parts of Low Rolling Plains and Texas/southwest Oklahoma border vicinity. Such development should occur by around 4pm-6pm CST as convective temperatures are breached.
Somewhat modest/nebulous large-scale ascent will probably support a multi-hour period of semi-discrete supercells even if effective shear is not robust and low-level shear/SRH a bit modest during time of initial development, but nonetheless steadily strengthening toward/after 00z/6pm CST. This will include associated threats for large to very large hail initially, potentially up to 2-3 inches in diameter. The increasing low-level shear through the evening will also foster enlarged low-level hodographs and the potential for a few tornadoes with this activity, potentially including a spatiotemporal window for a strong (EF2+) tornado even if a more complex mode is evolving. Over time, convection is forecast to grow upscale into a small but potentially intense cluster as it moves northeastward into parts of western/northern Oklahoma and southern Kansas.
Isolated supercells may also occur along the length of the dryline across west Texas late this afternoon/evening, with associated threat for occasional large hail and severe wind gusts. However, confidence in any more than isolated coverage remains low due to weak large-scale forcing. Farther north, isolated severe hail may occur tonight with elevated convection in a low-level warm advection regime across eastern Nebraska, northwest Missouri into Iowa.
Ohio Valley to the central Appalachians
A mid-level shortwave trough will move quickly eastward today across the Ohio 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 a few instances of damaging winds with loosely organized clusters that 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 Florida Peninsula, with dewpoints dropping into the mid 60s F. Despite the upper high, mid-level temperatures (-11 or -12C at 500mb) will remain relatively cool. Scattered convection appear probable along the western Florida Peninsula during the afternoon where low-level convergence will be maximized. Locally strong wind gusts will be possible, although organized severe thunderstorms are not expected.