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ACUS01 KWNS 030547

SWODY1

SPC AC 030546



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1246 AM CDT Wed Apr 03 2024



Valid 031200Z - 041200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE

MID-ATLANTIC TO FLORIDA...



...SUMMARY...

Strong to occasionally severe thunderstorms are possible on today

from the Mid-Atlantic to Florida. Primary hazard is damaging gusts,

but isolated hail and a tornado or two is also possible. Isolated

hail and a strong gust or two are also possible from southeast

Oregon into central Idaho.



...Synopsis...

A mid-latitude cyclone is forecast to deepen/mature as it moves

slowly eastward on today. Strong upper/mid-level flow will accompany

this cyclone, with 120 kt of 500 mb flow extending throughout its

eastern periphery from the Southeast through the Mid-Atlantic States

during the afternoon and evening. Occluded surface low associated

with this system currently over southern Lake Michigan will drift

slowly eastward beneath the upper cyclone. 



A secondary triple point low is currently developing to the

southeast of the occluded low, and this low will likely be over the

southwest VA vicinity later this morning. Expectation is for this

low to progress northeastward throughout the day, while the cold

front that extends southward from this low sweeps eastward.



Farther west, a deepening upper trough will approach the Pacific

Northwest coast late tonight/early Thursday morning. Enhanced

southwesterly flow preceding this trough will spread gradually

eastward across the Pacific Northwest into the northern Rockies.



...Mid-Atlantic southeastward to Florida...

Thunderstorms will likely be ongoing along and ahead of the cold

front mentioned in the synopsis, from the Mid-Atlantic southwestward

into the eastern FL Panhandle. Air mass preceding this front will be

characterized by ample low-level moisture (i.e. dewpoints in the

mid/upper 60s), but poor lapse rates and relatively modest buoyancy.

In contrast, robust wind fields will support strong vertical shear,

with 0-6 km bulk shear likely around 60 to 70 kt. Consequently, even

with limited buoyancy, a few stronger storms embedded within the

broader convective line are possible. Damaging gusts are the primary

severe risk, but isolated marginal hail and/or a brief tornado are

also possible.



The land area ahead of the front will be limited across GA and the

Carolinas where the outflow-augmented front will likely push

offshore by the early afternoon. Farther north in the Mid-Atlantic,

additional storm development is possible near the surface low during

the afternoon as moist southerly low-level flow facilitates air mass

destabilization in the wake of the morning activity. Kinematic

fields will remain very strong, and these storms will likely pose a

severe risk as they move rapidly northeastward. Damaging gusts are

the primary risk, but a tornado or two is possible as well. 



The severe threat will likely linger longer across central FL as

well. Here, sufficient instability expected ahead of the front

should maintain widespread storms, with shear supporting organized

convection. Locally damaging wind gusts are the primary risk, along

with some potential for marginal hail. Low-level flow will likely be

veered but there could still be enough curvature for a brief

tornado.



...Southwest OR into Central ID...

Mid-level moistening is anticipated across the region as upper

troughing approaches from the northwest. This moistening atop a

deeply mixed boundary will support modest buoyancy. Increasing

ascent will interact with this destabilizing air mass to support

thunderstorm development during the late afternoon. Deep-layer shear

should be strong enough to support updraft organization and

potentially a few supercells. These rotating updrafts may support

isolated hail, while high cloud bases support the potential for

strong outflow.



..Mosier/Bentley.. 04/03/2024



$$