906
ACUS01 KWNS 181631
SWODY1
SPC AC 181629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat May 18 2024

Valid 181630Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH FLORIDA AND SOUTHERN GEORGIA...AND PARTS OF THE WESTERN GREAT
LAKES...

...SUMMARY...
The greatest severe-thunderstorm potential today appears to be from
the Florida Panhandle eastward to the southern Atlantic Coast, and
portions of the western Great Lakes region.

...North FL/South GA...
A persistent band of widespread showers and thunderstorms extends
from the FL Panhandle into southern GA.  This band will sag
southward through the day, with occasional intensification along the
leading edge as daytime heating destabilizes the upstream
environment.  Locally gusty/damaging winds appear to be the main
threat.

...FL East Coast...
Strong heating is occurring along the FL peninsula, where hot/humid
conditions will be present this afternoon.  Westerly low-level flow
will focus a rather strong sea-breeze circulation, with most CAM
solutions suggesting scattered thunderstorm development.  It is
uncertain whether the activity will be along the immediate
coastline, or offshore.  However, sufficient vertical shear and CAPE
profiles indicate a risk of supercells capable of large hail and
perhaps a tornado/waterspout or two.


...Western Great Lakes into Central Plains...
A surface cold front will extend from western WI into parts of
IA/MO/KS by mid-afternoon.  Scattered thunderstorms are expected to
form along the front from the MN Arrowhead southward into western
WI, with more isolated convection from there southward into the
Plains states.  Forecast soundings in MI/WI/Upper MI show favorable
vertical shear profiles for a few supercell structures capable of
hail and damaging wind gusts.  Therefore have added a SLGT risk area
for that scenario.  From IA south, relatively weak winds in the
lowest 6km and a deep sub-cloud layer suggest outflow dominant
storms with a more marginal severe threat.

...CO/Western KS...
Model guidance and water vapor imagery show a plume of mid-level
moisture spreading into central CO.  This should result in a cluster
of thunderstorms over the mountains by mid-afternoon, spreading
eastward into the Plains this evening.  Inverted-v sounding profiles
and favorable westerly flow aloft will promote gusty/damaging wind
potential in some of this activity.

...MS/AL into the Carolinas...
A relatively moist and unstable air mass is in place today across
the TN Valley into the Carolinas.  Little cap and pockets of daytime
heating will lead to scattered afternoon thunderstorms throughout
the region - with some potential for locally gusty/damaging wind
gusts.  Areas of slightly greater focus for concern of strong storms
are 1) Ahead of the MCV currently over northern MS, and 2)  an axis
from northern AL into central NC along the northern edge of slightly
stronger winds aloft.

..Hart/Jewell.. 05/18/2024

$$