ACUS02 KWNS 031746
SWODY2
SPC AC 031745
Day 2 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1245 PM CDT Fri Apr 03 2026
Valid 041200Z - 051200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY AFTERNOON
AND EVENING ACROSS PARTS OF SOUTHEASTERN INDIANA...NORTHERN
KENTUCKY...MUCH OF OHIO...SOUTHEASTERN LOWER MICHIGAN...WESTERN
PENNSYLVANIA AND NEW YORK...
CORRECTED FOR WORDING AND TYPOS
...SUMMARY...
Severe thunderstorms may develop and overspread the lower Great
Lakes vicinity and middle through upper Ohio Valley Saturday
afternoon and evening, accompanied by strong to severe wind gusts
and potential for a couple of tornadoes.
...Discussion...
As mid-level ridging builds further across the British Columbia and
Pacific Northwest vicinity Saturday through Saturday night, models
indicate that several digging downstream short wave troughs across
the Canadian Prairies into the northern U.S. Great Plains may
contribute to the northeastward acceleration of a notable mid-level
low, now slowly turning eastward toward the middle Missouri Valley.
In response to these developments, an initially modest surface
cyclone associated with the lead perturbation is generally forecast
to undergo substantive deepening while occluding across and
northeast of the upper Great Lakes vicinity. A secondary cyclone
may form across the southeastern Michigan through Lake
Huron/Georgian Bay/adjacent Ontario vicinity by Saturday afternoon,
with a trailing cold front continuing to advance east of the
Mississippi Valley and southward through the southern Great Plains,
into the Appalachians/lower Mississippi Valley/northwest Gulf coast
vicinity by early Sunday.
Initially cold, stable air to the north of a preceding front may
remain entrenched across much of New England through this period,
while widespread thunderstorm development today through tonight cuts
off the advection of elevated mixed-layer air and associated steeper
mid-level lapse rates to the east of the Mississippi Valley. At the
same time, the impact of lingering pre-frontal convective
development, associated surface outflow and northeastward/eastward
advecting remnant cloud cover on subsequent destabilization within a potentially expanding warm sector across the mid/upper Ohio Valley
and lower Great Lakes region remains unclear.
...Ohio Valley into lower Great Lakes region...
Conditionally, a relatively moist (60+ F surface dew points) air
mass within the evolving warm sector is likely to become conducive
to organized severe thunderstorm development, including supercells,
Saturday afternoon and evening. However, stronger mid/upper support
for ascent may remain displaced to the northwest of much of the
destabilizing warm sector, with strongest forcing for convection
confined to the front, or, perhaps more likely, a conglomerate
pre-frontal outflow.
Although the signal in model output is not particularly strong, it
appears possible that convection may begin re-intensifying along the
leading outflow boundary while overspreading southeastern Lower
Michigan into the lower Ohio Valley by early afternoon. As this
occurs, strong lower/mid-tropospheric shear beneath south to
southwesterly wind fields strengthening to 40-60+ kt in the 850-500
mb layer will be more than sufficient to support organization and
increasing risk for severe wind gusts and tornadoes. This threat
likely will persist as activity overspreads much of the remainder of
the Ohio Valley and lower Great Lakes region into Saturday evening.
...Parts of the Mid South into northwestern Gulf Coast...
Weaker mid/upper forcing for ascent, deep-layer mean wind field and
shear suggest more limited severe weather potential than further
north. However, somewhat better boundary-layer moisture, including
mid 60s F+ dew points, may contribute moderate CAPE ahead of
southeastward advancing convective outflow. It appears possible
that this could support re-intensification of convection that could
become accompanied by sporadic damaging downbursts late Saturday
afternoon into evening.
..Kerr.. 04/03/2026
$$
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