Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun May 11 2025 05:43:41 ACUS01 KWNS 110543 SWODY1 SPC AC 110542 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Sun May 11 2025 Valid 111200Z - 121200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST ID TO CENTRAL/EASTERN MT... ....SUMMARY... Scattered severe gusts are possible across a part of the Northwest from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ....Northern Rockies/High Plains and northeast Great Basin... A broad upper trough, consisting of multiple embedded shortwave impulses, will largely remain anchored off the BC and Pacific Northwest Coast. A fast mid-level jet, in excess of 70 kts at 500 mb, will overspread northern CA today and expand towards the northern Rockies through 12Z Monday. Displaced northeast of this strong flow regime, a broad swath of isolated to scattered thunderstorms is expected to peak during the late afternoon and early evening. Similar to Sunday, sporadic severe gusts appear to be the primary hazard owing to deeply mixed boundary layers, especially with eastern extent from southeast ID to central/eastern MT. Pockets of modest buoyancy, coupled with moderate to strong deep-layer southwesterly speed shear, could yield a few high-based supercell structures producing small to marginally severe hail. This should be focused from the OR/WA/ID border area into central MT, and separately over southeast ID into Yellowstone. These structures may further aid in the downstream severe wind threat in MT. ....Southeast... A mid/upper cyclone will drift east across the Sabine to Lower MS Valleys through early Monday. The belt of stronger mid/upper flow will largely remain centered over the northeast Gulf Coast, with weaker branches curling northwest towards the Mid-South and the other continuing across the South Atlantic Coast. Thunderstorm clusters are expected to be ongoing across the northeast Gulf through the FL Panhandle into southeast AL/southwest GA and near coastal SC. The primary concern with the Panhandle to Chattahoochee Valley convection is for potential of a tornado or two and locally damaging winds through late morning. A 30-40 kt low-level jet is expected to sustain adequately enlarged low-level hodographs, especially towards the coast. But convection is expected to be within a messy, outflow-dominated mode by 12Z given near-parallel alignment of the deep-layer shear vector and initial north/south-oriented convective swath. More widespread convection should form along large-scale outflow into the afternoon, which will tend to push east-northeast, and sea breeze boundaries. Downstream wind profiles appear less favorable for organized storms. Weak mid-level lapse rates should further marginalize/maintain an isolated severe threat towards the South Atlantic States. Farther west in AL to MS, despite somewhat cooler mid-level temperatures closer to the upper cyclone, lapse rates still appear modest. But deep-layer speed shear will be moderately favorable amid a nearly unidirectional southeasterly wind profile. A few cells may briefly produce marginally severe hail and locally strong gusts, mainly from late afternoon into mid-evening. ...Grams/Lyons.. 05/11/2025 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .