SPC Apr 3, 2024 0600 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 1200Z Day 1 Outlook

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

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