ACUS01 KWNS 111253
SWODY1
SPC AC 111252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Thu Apr 11 2024

Valid 111300Z - 121200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR EASTERN
OHIO AND NORTHWEST WEST VIRGINIA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR FAR SOUTHERN
GEORGIA INTO NORTH AND CENTRAL PARTS OF FLORIDA...

...SUMMARY...
Severe thunderstorms with a few tornadoes, scattered damaging winds,
and isolated large hail are possible across the upper Ohio River
Valley and parts of the Appalachians this afternoon. Scattered
damaging winds and a couple of tornadoes are possible in far
southern Georgia into central Florida, mainly this morning through
early afternoon.

...Synopsis...
Water-vapor imagery this morning shows a potent mid-level low/trough
centered near the AR/MS/TN border with an upstream trough over the
Upper Midwest forecast to phase with the Southeast trough. A
cyclone near the TN/MS border will deepen as it develops
north-northeast into the Lower Great Lakes by early evening. A
trailing surface cold front will push east across portions of the Southeast/southern Appalachians during the day, before clearing the
Southeast coast by early Friday morning.

...Upper OH River Valley...
Considerable uncertainty remains for this forecast in terms of the
magnitude of destabilization across the OH Valley late this morning
through the afternoon. This uncertainty is primarily due to low
cloud cover and weak capping resulting in scattered
showers/low-topped thunderstorm activity and the potential to remain
relatively cool in the boundary layer. However, mid-level dry air
evident in water-vapor imagery is wrapping through the base of the
mid-level low/trough over TN, and this mid-level dry intrusion
forecast to spread northeast into portions of the Upper OH Valley.
Weak instability coupled with some enlargement of the hodograph can
support an environment in which discrete cells and semi-discrete
clusters evolve into supercells. A few tornadoes are possible if
stronger updrafts/supercells manage to develop, in addition to an
accompanying threat for damaging gusts and perhaps marginally severe
hail.

...Florida/Georgia...
Ongoing pre-frontal broken band of strong to severe thunderstorms
over north FL and the eastern Gulf of Mexico will gradually shift
east across the northern half of the Peninsula through the morning
and into the afternoon. The northern rim of rich low-level moisture
(upper 60s to lower 70s deg F surface dewpoints) have advected into
north FL early this morning. Although lapse rates will remain
modest, it appears the richer moisture will contribute to adequate surface-based buoyancy (500-1250 J/kg MLCAPE) across the northern
half of the Peninsula today. The Jacksonville and Tampa 88D VAD
wind profiles are quite strong this morning and will likely remain
so through the early afternoon as the larger-scale mid-level trough
pivots eastward over the FL Peninsula by early evening. The risk
for a couple of tornadoes and damaging gusts will likely maximize
through the midday before the thunderstorm band moves offshore and
forcing for ascent gradually abates by late afternoon as the
synoptic low lifts well to the north.

...Mid-Atlantic states into Carolinas...
A less focused and more conditional severe risk seems evident for
the Carolinas later this afternoon and northward into the
Mid-Atlantic states this evening as the upper trough encroaches on
the general region. A broad warm-air advection regime north of the
FL/GA early-day MCS will slowly destabilize today, aided in part by
lower 60 deg F dewpoints north, mid to upper 60s south. Long
hodographs will favor storm organization with any robust updrafts.
Isolated to widely scattered strong to severe storms capable of a
threat for damaging gusts and a couple of tornadoes are possible,
mainly over parts of western VA, with lower coverage expected
farther east over the coastal plain/Delmarva.

..Smith/Mosier.. 04/11/2024

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