Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
285 ACUS48 KWNS 060900 SWOD48 SPC AC 060858 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Mon May 06 2024 Valid 091200Z - 141200Z ...DISCUSSION... ...Day 4/Thursday... Medium-range guidance is in reasonable agreement showing an upper trough moving gradually eastward from the Midwest/OH Valley and Great Lakes to the Eastern Seaboard on Thursday. A weak surface low initially over the OH Valley should likewise advance eastward through the day while slowly deepening, and eventually reaching the Mid-Atlantic by Thursday evening. A moist low-level airmass should be in place across the Southeast, and extend northeastward into parts of the Carolinas and Mid-Atlantic ahead of a cold front. Weak to moderate instability should develop ahead of the front with daytime heating. Mid-level flow and related deep-layer shear is likewise expected to slowly increase through the day with the eastward progression of the upper trough. Thunderstorms should gradually increase in coverage and intensity through the afternoon, especially along/east of the Blue Ridge and Appalachian Mountains. Confidence in organized severe thunderstorms occurring has increased enough to add a broad 15% severe area from GA to the Mid-Atlantic. A separate area of potential severe thunderstorms has also become apparent across parts of TX on Thursday. A weak/low-amplitude shortwave trough should advance northeastward from northern Mexico across the southern Plains through the day, providing ascent needed to initiate convection along a surface front/dryline. A very moist and unstable airmass will likely be present south/east of these boundaries, and deep-layer shear appears sufficiently strong for severe thunderstorms capable of producing mainly severe hail and damaging winds. In between the two 15% severe areas, some severe threat should also exist across the Southeast. However, the effect of a possible overnight/early Thursday morning MCS may complicate destabilization and related severe potential later in the day. Have therefore not included the central Gulf Coast States in a 15% severe delineation at this time. ...Day 5/Friday - Day 8/Monday... Limited severe potential should become increasingly confined to the immediate Gulf Coast and FL from Friday into the upcoming weekend, as a cold front continues southward. By Sunday into early next week, there are some indications in guidance that low-level moisture may begin to return northward across the southern Plains. However, model spread is large at this extended time frame, and predictability remains low. ..Gleason.. 05/06/2024