Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
995 ACUS02 KWNS 121739 SWODY2 SPC AC 121737 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1237 PM CDT Sun May 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MUCH OF EASTERN TEXAS EASTWARD ACROSS THE GULF COAST STATES... ...SUMMARY... Severe thunderstorms are expected Monday over a large region from central and east Texas across parts of the Gulf Coast states. The potential may develop for corridors of significant wind gusts and very large hail, and a few tornadoes. ...Synopsis... A shortwave trough will move east from the central and southern Plains Monday into the Middle to Lower MS Valley through Tuesday morning, while an upper high remains centered over Cuba. As this trough moves east, heights will lower gradually across the region, with a slow flattening of the ridge along the Gulf Coast. Midlevel winds of 50-60 kt will be common, while stronger 70-90 kt flow at 300 mb shifts northeastward with the shortwave trough from the ArkLaTex into the OH/TN Valleys. At the surface, a weak low/trough will develop from northern MO southward across the ArkLaTex and into southern TX. A very moist air mass will exist from eastern TX into the lower MS Valley, with increasing moisture late in the period across southern AL, GA, and FL as a warm front lifts north. The robust moisture will result in widespread clouds and precipitation throughout the period, which will complicate the forecast. In general, a relatively large area of substantial moisture and instability will stretch from TX eastward toward the central Gulf Coast during the day, beneath moderate westerlies aloft which will enhance deep-layer shear. Stronger low-level shear will be relegated to the warm front area, from AL into GA and northern FL, with various corridors of severe potential possible. ...Eastern TX into western GA... A complex forecast exists for Monday, with multiple areas of potential within a broad zone, and at various times of the day. While significant wind and hail will clearly be possible, predictability is low regarding the precise corridors of enhanced risk potential. Early on Monday, storms are expected to be ongoing from MS into AL and the FL Panhandle, related to warm/moist advection near and north of a warm front. Some of this activity immediately near the warm front may have a hail and tornado risk, as instability rapidly increases in proximity to stronger low-level effective SRH centered over southern AL. To the west, early-day storms are also anticipated from the ArkLaTex into east-central TX, beneath cooler temperatures aloft and where mid 70s F dewpoints will be in place. This activity may produce large hail, and eventually grow upscale into larger clusters or an MCS across eastern TX, LA and western MS through 00Z. Forecast soundings show ample instability, and moderate mid to high level winds, but with weak flow below 700 mb, suggesting MCS potential. Depending on the track of that activity, and the position of any outflows from the earlier storms farther east, the severe wind and hail risk may overspread additional areas extending again into AL and GA. As previously mentioned, potential air mass overturning and condition of the unstable boundary layer are the main uncertainties, and therefore the entire region remains in 15% Slight Risk category. However, corridor(s) of Enhanced Risk may be considered into the day 1 period. ..Jewell.. 05/12/2024 $$