ACUS02 KWNS 170604
SWODY2
SPC AC 170603

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
0103 AM CDT Fri May 17 2024

Valid 181200Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE FLORIDA
PANHANDLE INTO THE EASTERN CAROLINAS...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible across
portions of the Southeast States and Carolinas, and parts of the
Upper Midwest on Saturday.

...Central Gulf Coast/Southeast vicinity...

An upper trough will spread east across the Southeast U.S. on
Saturday. An accompanying band of enhanced southwesterly mid/upper
level flow will overspread the region ahead of this feature, with
500 mb winds around 50-80 kt indicated in forecast guidance (30-40
kt from 850-700 mb). At the surface, dewpoints from the mid 60s to
the mid 70s F are forecast. Modest midlevel lapse rates atop this
very moist airmass will aid in moderate destabilization (MLCAPE
1500-2500 J/kg). This overall environment will support organized
convection ahead of the upper trough and a southeastward-advancing
cool front.

Convective evolution is still uncertain. It is likely convection
(possibly a linear MCS) will be ongoing Saturday morning in the
vicinity of the central Gulf Coast. This activity should track east
into southern GA/northern FL through the day posing a primary hazard
of damaging gusts. The northward extent of this MCS is uncertain,
but may develop into parts of SC/NC. The evolution of this system
may have impacts on the environment further north across MS/AL and
northern GA through peak heating. Though, additional convection is
still expected to develop by mid afternoon further north ahead of
the advancing cold front.

Given an overall favorable pattern supporting organized convection,
a broad area of severe probabilities is delineated across the
Southeast. A Slight risk (level 2 of 5) has been introduced where
the airmass should be mostly undisturbed ahead of the morning MCS
from the FL Panhandle into parts of SC and southeast NC. A broader
Marginal risk (level 1 of 5) enveloping much of the region to the
north of the Slight risk has been expanded compared to the previous
Day 3 outlook given a favorable environment, but uncertainty
continues.

...Northern Wisconsin/Upper Peninsula vicinity...

A somewhat compact upper shortwave trough within broader
cyclonically curved flow across the northwestern U.S. will move
across the Upper Midwest Saturday afternoon/evening. Enhanced
southwesterly mid/upper flow (around 40-50 kt) will overspread the
region. At the surface a sharp cold front will surge east across MN
into WI and the U.P. of MI from late afternoon into early evening.
Boundary-layer moisture will remain modest, with forecast dewpoints
from the upper 50s to near 60 F. Strong heating will allow for
steepening low-level lapse rates and aid in modest destabilization
(MLCAPE to around 1000 J/kg). Effective shear magnitudes around
30-35 kt will support organized storms, and possibly supercells. A
few strong to severe gusts and marginal hail will be the main
concerns with isolated convection through early/mid evening.

..Leitman.. 05/17/2024

$$