Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
679 ACUS02 KWNS 141726 SWODY2 SPC AC 141725 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Tue May 14 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN NORTH-CENTRAL FL PENINSULA AND THE TX PANHANDLE TO SOUTHEAST KS... ...SUMMARY... Scattered severe thunderstorms are possible Wednesday into Wednesday evening over parts of the north-central Florida Peninsula and in the southern Great Plains. ...Synopsis... A shortwave trough from the OH Valley to the Deep South will move off the South Atlantic Coast by early Thursday. Attendant surface cyclone will further occlude and decay over the Central OH Valley, while secondary cyclogenesis occurs just offshore of the VA/NC coast. Farther west, a series of lower-amplitude shortwave impulses will gradually move east across parts of the Upper Midwest to Southwest states. ...FL Peninsula... At least scattered thunderstorms are expected to be ongoing across the northeast Gulf into north FL ahead of a weak surface front pushing southeastward. Ample buoyancy characterized by MLCAPE of 2000-3000 J/kg will likely develop across central and south FL where more robust boundary-layer heating occurs south of the morning convective canopy amid a plume of steep mid-level lapse rates. Consensus of 12Z CAM guidance suggests downstream thunderstorm development will occur late morning through midday as MLCIN wanes, with the leading edge of large-scale convective outflow serving as the effective boundary focus through the day. Deep-layer shear will be strong with a belt of 50-60 kt mid-level flow south of the aforementioned shortwave trough. Although the flow regime should be largely unidirectional from the southwest, this will be sufficient for at least a few supercells. Large hail and a couple tornadoes will be the primary threats, along with isolated damaging winds. Overall threat should wane later in the afternoon as flow orientation becomes increasingly parallel to the composite outflow/front. ...Central/southern Great Plains into the Mid-MO Valley... A generally north/south-oriented cold front to the south of a weak surface cyclone over eastern SD will serve as a focus for scattered late afternoon and evening thunderstorm development over the central states. Airmass modification will be most pronounced across OK into south KS where low 60s boundary-layer dewpoints will spread north from east TX. This should yield a confined plume of moderate MLCAPE from 1500-2500 J/kg by peak heating. Weak buoyancy will be prevalent to the north of this plume and suggests the overall severe threat in the Mid-MO Valley should remain marginal. Farther south, low-level convergence near the front and dryline, along with post-frontal upslope in the Raton Mesa vicinity, and a strengthening low-level jet from west TX towards the southeast KS/northeast OK border should all aid in scattered to eventually widespread convective development by Wednesday evening. While the combination of boundary-layer moisture and deep-layer shear will be modest by mid-May standards, it should be adequate for transient supercells and clusters capable of large hail and severe wind gusts. These threats should wane overnight. ...Carolinas... Moderate destabilization is anticipated ahead of the slow-moving shortwave trough, mainly across the coastal Plain. Isolated to scattered thunderstorms are expected during the afternoon as this wave moves through. Modest deep-layer shear should promote a predominant multicell mode. The more robust storms should be strong enough to produce sporadic hail and localized damaging winds. ..Grams.. 05/14/2024 $$