SPC May 9, 2025 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1130 AM CDT Fri May 09 2025

Valid 091630Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN
FLORIDA PENINSULA INTO SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH
CAROLINA...AND ACROSS EASTERN NORTH CAROLINA/FAR SOUTHEAST
VIRGINIA...

...SUMMARY...
Thunderstorms capable of producing large hail and severe wind gusts
are possible across parts of the Mid-Atlantic and Southeast,
especially from the eastern Florida Peninsula through southeast
Georgia, and across northeastern North Carolina/far southeast
Virginia.

...Synopsis...
Recent satellite imagery shows a pair of cyclones embedded within a
large positively titled upper trough extending from the southern
Plains through the Northeast. The northernmost/easternmost cyclone
is centered over the Lower Great Lakes vicinity, and is forecast to
move gradually eastward throughout the day, ending the period over
southern New England. An associated surface low, which is currently
centered over eastern NJ, is forecast to progress northeastward
while becoming increasingly aligned with the mid-level cyclone. A
cold front extends southwestward from this low across VA and then
back westward across KY, southern IL, and central MO. As the low
moves northeastward, this front is expected to gradually push
southward/southeastward, moving through much of the Mid-Atlantic by
this evening. 

The southernmost/westernmost embedded cyclone is currently centered
over southern AR, and the expectation is for the cyclone to shift
southeastward throughout the day, ending the period over the Lower
MS Valley. Primary surface low associated with this system is
currently over the northwest Gulf. This low is forecast to progress
slowly eastward along the central Gulf coast, remaining just off
shore and likely reaching just off AL/MS border intersection by
early tomorrow morning.

...Central Gulf Coast into FL...
A modest, convectively enhanced vorticity maximum is forecast to
move from the central FL Panhandle into southeast GA/northern FL
today, well ahead of the mid-level cyclone and associated surface
low described in the synopsis. Localized ascent attendant to this
features coupled with modest large-scale forcing for ascent and
airmass destabilization will result in early-afternoon thunderstorm
development, particularly along any sea breeze boundary that
develops. Vertical shear will be modest, resulting in a mostly
multicellular mode. Even so, updrafts are still expected to be
strong enough to produce damaging downbursts and isolated large
hail.

Later tonight, some additional organization/strengthening of a
convective line near the surface low is possible. Some strengthening
of the low-level flow could occur at the same time, resulting in a
low-probability tornado risk along the coast from AL into the
western and central FL Peninsula. 

...Mid-Atlantic into the Carolinas...
Afternoon thunderstorm development is anticipated across the region,
with the highest coverage from the VA Tidewater into east-central
NC, where forcing along the cold front will be strongest. The
strongest shear is anticipated across this region as well, but the
overall magnitude should still be modest, with most guidance
suggesting deep-layer shear around 35 kt. Buoyancy will be modest as
well, with MLCAPE likely maximizing around 800 to 1000 J/kg. These
environmental conditions support the potential for a few stronger,
more organized updrafts capable of damaging wind gusts and isolated
large hail.

..Mosier/Squitieri.. 05/09/2025

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