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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.


Tuesday, April 2, 2024

SPC Apr 2, 2024 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0732 AM CDT Tue Apr 02 2024

Valid 021300Z - 031200Z


A severe weather outbreak is possible today over the Ohio Valley
with the broader severe weather risk including parts of the
Southeast. Strong and potentially long-track tornadoes are possible
from Indiana and Ohio southward into the Mid South. A threat for
strong tornadoes may focus this evening into tonight across parts of
Alabama and Georgia.

A complex and strongly dynamic spring storm system will potentially
result in a large area of severe-weather risk from the southern
Great Lakes/OH Valley southward into portions of the Deep South,
including AL/GA and the western Carolinas late tonight.

A potent trough over the Upper Midwest this morning will evolve into
a very strong mid-level low over the southwest Great Lakes by
Wednesday morning. An intense mid-level speed max over northern
Mexico/TX, in association with the southern portion of the
larger-scale central U.S. trough, will rapidly move east-northeast
during the period and intensify to 125-kt at 500 mb over the
southern Appalachians by daybreak Wednesday. Intense 12-hr midlevel
height falls are forecast across much of the Great Lakes, OH/TN
Valley, and the northern Gulf States, where values in excess of 200m
are expected during the latter half of the period. The synoptic
front this morning is draped across the OH Valley and will likely
advance north due to the digging trough.

...OH Valley...
Water-vapor imagery loop overnight showed a southern-stream
short-wave trough associated with this morning's severe thunderstorm
activity straddling the OH River in central KY and southern IN.
This early-day thunderstorm complex will probably pose a risk for
wind damage and perhaps a couple of tornadoes before it moves into
the central Appalachians towards midday (see MCD #341 for short-term
details). In its wake, a trailing outflow boundary/effective warm
frontal zone will likely advance northward into IN/OH later today
with lower to mid 60s progged to near I-70. Models continue to show
an appreciable window of opportunity in which cloud breaks/heating
and increasing low-level moisture contribute to moderate
destabilization during the afternoon. Have adjusted the western
envelope of severe probabilities farther west across IN to account
for greater destabilization than earlier forecast, but otherwise
have left the outlook unchanged across the OH Valley. Scattered
thunderstorms will likely develop by early to mid afternoon with
discrete supercells evolving from the more intense updrafts.
Tornadoes, large to very large hail, and damaging gusts are expected
with the supercells that mature across the warm sector. Enlarged
and elongated hodographs imply fast storm motions and the
possibility for several cyclic tornadic supercells, some of which
may yield strong and long-lived tornadoes.

Farther east, strong to severe storms may continue across the
central Appalachians and perhaps move east into the Mid-Atlantic
states. Hail/wind appear to be the primary hazards with this

...Southeast this evening/tonight...
Farther south and initially in the TN/MS/northern AL vicinity,
severe thunderstorms are forecast to develop this afternoon as the
leading edge of stronger large-scale ascent impinges on the region.
A moisture-rich airmass and wind profile favoring supercells, will
favor a risk for all severe hazards with the stronger thunderstorms.
Although it remains unclear with regard to daytime to evening storm
evolution across MS/AL/TN, the approach of the 500-mb speed max and
intense shear through a deep layer atop a moist/unstable boundary
layer, suggest a bimodal severe threat will probably evolve this
evening into the overnight. Model guidance indicates messy but
organized storm modes within a larger area of convection will
probably develop. Forecast soundings show 300-500 m2/s2 0-1 km SRH
from central/eastern AL into GA during the evening and overnight.
The risk for tornadoes, including a few strong tornadoes, will be
possible with this activity eventually reaching the Carolinas and
the eastern FL Panhandle late.

..Smith/Leitman.. 04/02/2024

SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)