####018002774####
ACUS01 KWNS 220454

SWODY1

SPC AC 220452



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1152 PM CDT Sun Apr 21 2024



Valid 221200Z - 231200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE

SOUTHEAST FLORIDA PENINSULA...



...SUMMARY...

Strong to locally severe thunderstorms, capable of marginally severe

wind gusts and hail, will be possible across the southeast Florida

Peninsula this afternoon.



...South Florida...



An upper trough oriented from the Carolinas to the Southeast will

shift east over the Atlantic waters by 00z. A belt of enhanced

mid/upper westerly flow associated with the trough will overspread

much of FL.



At the surface, a cold front located over central FL will shift

south through late afternoon. Ahead of the front, a moist airmass is

already in place, with surface dewpoints in the upper 60s F.

Modestly steep midlevel lapse rates atop this moist boundary-layer,

coupled with daytime heating, will foster MLCAPE values to around

1000-1500 J/kg. The greatest instability will be focused near the

southeast FL coast. Low-level flow will remain light and mainly

parallel to the surface front, limiting convergence. Still,

inhibition is forecast to be weak and thunderstorms are expected by

afternoon near the surface front. Elongated hodographs, and around

35 kt effective shear magnitudes suggest supercells are possible.

However, given weak forcing and possible strong outflows given steep

low-level lapse rates beneath 850 mb, clustering may also be

possible. Strongest convection will likely be confined to near the

southeast FL coast. Locally strong/damaging gusts and perhaps

marginally severe hail possible through late afternoon.



...Central Plains...



An upper shortwave trough will migrate across the northern Plains,

with height falls extending into the central Plains this

afternoon/evening. A dearth of boundary-layer moisture is forecast

in the wake of a cold frontal intrusion deep into the Gulf of Mexico

and a large area of surface high pressure extending from the

southern Plains to the Mid-South/TN Valley. Nevertheless, modest

midlevel moisture is forecast over the region amid a plume of steep

mid and low-level lapse rates. Minor elevated instability (generally

750 J/kg MUCAPE or less) is evident in forecast soundings above a

warm layer around 700 mb. Some weak convection is expected and a few

strong gusts or small hail is possible across southern NE into

northern KS. However, longevity of stronger updrafts appears limited

and coverage of convection is expected to be low, precluding

marginal severe probabilities at this time.



..Leitman/Weinman.. 04/22/2024



$$