Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
222 ACUS02 KWNS 260509 SWODY2 SPC AC 260507 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1207 AM CDT Sun May 26 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MONDAY INTO MONDAY NIGHT ACROSS PARTS OF EASTERN WEST VIRGINIA...SOUTHERN PENNSYLVANIA...MUCH OF VIRGINIA AND MARYLAND...NORTHERN NORTH CAROLINA...DELAWARE AND SOUTHERN NEW JERSEY...AS WELL AS ACROSS MUCH OF WESTERN GEORGIA...ALABAMA...CENTRAL AND SOUTHERN MISSISSIPPI AND EASTERN LOUISIANA...... ...SUMMARY... Severe thunderstorms are possible across parts of the Mid Atlantic and the Gulf Coast states Monday into Monday night, with severe wind and hail the primary potential hazards. ...Synopsis... Mid/upper flow still appears likely to undergo amplification across the northern mid-latitudes of the Pacific and western North America into and through the Memorial Day Holiday. This is forecast to include digging troughing offshore of the Pacific Northwest coast, to the south of a broad low developing across the northeastern Pacific, and building downstream ridging across the northern U.S. Rockies and Canadian Prairies. Farther downstream, several short wave perturbations are forecast to consolidate into more prominent larger-scale troughing across the mid/upper Mississippi Valley into the northern and middle Atlantic Seaboard. One of the more prominent perturbations appears likely to turn northeast of the Lake Huron/Georgian Bay vicinity during the day, accompanied by a relative compact, but deep, surface cyclone. In its wake, a remnant plume of elevated mixed-layer air likely will become increasing suppressed across the Southeast and lower Mississippi Valley, while a surface cold front advances into and across the Appalachians. Preceding the front, surface troughing is forecast to deepen to the east of the Blue Ridge during the day, beneath increasingly difluent and divergent upper flow, downstream of a short wave trough pivoting east-northeast of the lower Ohio Valley. ...Mid Atlantic.. Latest model output appears a bit weaker than prior guidance with regard to the wave emerging from the lower Ohio Valley, and a little more unclear concerning more subtle, perhaps convectively generated, perturbations preceding this wave. However, a seasonably moist boundary layer to the east of the deepening lee surface troughing is still forecast to become characterized by sizable CAPE as 40-50+ kt west-southwesterly mid-level flow noses northeast of the southern Appalachians. This is expected to contribute to an environment potentially conducive to organized thunderstorm development, including supercell structures. It still appears possible that consolidating pre-cold frontal convection across and east of the Allegheny Mountains could intensify and organize further to the east of the Blue Ridge by late afternoon, accompanied by potentially more widespread strong to severe wind gusts into Monday evening. ...Gulf States... Beneath a remnant plume of relatively steep lower/mid-tropospheric lapse rates, seasonably high boundary-layer moisture content is forecast to contribute to large CAPE on the order of 2000-4000+ J/kg by late Monday afternoon, along a corridor across the lower Mississippi Valley into the southern Appalachians. Beneath modest, broadly cyclonic mid-level flow, the initiation of vigorous thunderstorm development appears probable by late Monday afternoon. The latest NAM, in particular, is suggestive that upscale growth may contribute to a substantive surface cold pool and rear-inflow which may be accompanied by increasingly widespread strong to severe surface gusts across Alabama and adjacent portions of western Georgia, central and southern Mississippi. It is possible severe probabilities may need to be increased further across this region in later outlooks, as model spread decreases. ..Kerr.. 05/26/2024 $$