####018002684#### ACUS01 KWNS 220555 SWODY1 SPC AC 220554 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Fri Mar 22 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA KEYS... ...SUMMARY... Thunderstorms, associated with a wind-damage, hail and isolated tornado threat, will be possible this evening across parts of the Florida Keys. A marginal severe threat is also expected across parts of south Florida and the central to eastern Gulf Coast. ...Central and Eastern Gulf Coast... An upper-level trough will move into the western Gulf of Mexico today. Ahead of the trough, a moist airmass will advect northward into the central and eastern Gulf Coast. Surface dewpoints are expected to reach 60+ F just to the east of surface low tracking through the central Gulf Coast. Ahead of the low, convergence is forecast to become maximized near a warm front located just offshore to near the coast. Model forecasts suggest that a band of thunderstorms will develop around midday along this zone of low-level convergence. The moist airmass, along with moderate deep-layer shear and strong low-level convergence, will likely contribute to a marginal severe threat. Rotating storms that develop and move onshore could be associated with wind damage, hail and a marginal tornado threat. ...South Florida... A mid-level jet will move across the central and eastern Gulf of Mexico today, as an upper-level system approaches from the west. At the surface, a low is forecast to develop and move toward the southern Florida Peninsula this afternoon. A moist airmass, with surface dewpoints in the mid to upper 60s F, will advect northward into far south Florida by early evening, where RAP forecast soundings increase MLCAPE into the 1000 to 1500 J/Kg range. Scattered thunderstorms, associated with lift ahead of the approaching system and the stronger instability, are forecast to move into the Florida Keys by early this evening. Convective coverage will likely gradually increase as an MCS moves across the southern Florida Peninsula. RAP forecast soundings in the Florida Keys this evening have 0-6 km shear of 50 to 60 knots, and 0-3 storm-relative helicity increasing to between 250 and 300 m2/s2. This could support a tornado threat with rotating cells that move across far south Florida ahead of the approaching MCS. Marginally severe gusts, hail and a tornado or two will be possible, mainly in the Florida Keys, where severe parameters are forecast to become maximized. ..Broyles/Squitieri.. 03/22/2024 $$ ####018003207#### ACUS02 KWNS 220558 SWODY2 SPC AC 220556 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Fri Mar 22 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTH FLORIDA/THE KEYS...AND EASTERN NORTH CAROLINA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Saturday across parts of south Florida and the Keys, along with eastern North Carolina/the Outer Banks. ...Synopsis... Two upper troughs will advance across the eastern states on Saturday, with the southern-stream upper trough progressing over the Southeast and eventually the western Atlantic through Saturday evening. An initially weak surface low over GA should redevelop along/near the Outer Banks of NC by Saturday afternoon. Multiple surface lows will probably form through Saturday evening along the length of a cold front given the split-flow pattern aloft and various sources of large-scale ascent. Greater low-level moisture should remain confined to parts of south FL and the Keys, along with eastern NC/the Outer Banks. ...South Florida and the Keys... A parade of thunderstorm clusters over the Gulf of Mexico will likely impact parts of the FL Peninsula and the Keys in the Day 1 period. This convection should tend to hamper daytime heating and related destabilization across south FL Saturday morning as a southern-stream upper trough moves eastward. An effective front/convectively reinforced outflow boundary will probably be located over the Keys/FL Straits at the start of the period. The potential for weak to moderate instability to develop north of this boundary remains questionable. Still, some guidance suggests this may occur, especially if an overnight/early Saturday morning MCS from the Day 1 time frame remains farther north towards the east-central Gulf and central FL Peninsula. Enhanced mid-level flow of 50-70 kt attendant to the upper trough and related strong deep-level shear will conditionally support robust/severe thunderstorms, should they develop across south FL and the Keys. Isolated damaging winds appear to be the greatest threat with any thunderstorm clusters that can persist and remain surface based. But, sufficient low-level shear should also be present Saturday morning to pose some risk for a tornado. This isolated severe threat will shift quickly offshore by Saturday afternoon in tandem with an eastward-moving cold front. ...Eastern North Carolina... At least low 60s surface dewpoints will attempt to advance inland across parts of eastern NC Saturday in tandem with a developing surface low. Greater instability is generally expected to remain offshore, but weak MLCAPE may develop over this region with filtered daytime heating behind early-day convection. This morning convection will be in a strongly sheared, but only modestly unstable environment. If additional thunderstorms can form along/ahead of the cold front, they could become strong to severe while posing an isolated threat for damaging winds and perhaps a tornado. ..Gleason.. 03/22/2024 $$