RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0742 AM CDT Sun May 03 2026
Valid 031300Z - 041200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
NORTHERN/CENTRAL MISSOURI AND CENTRAL ILLINOIS ON SUNDAY....
...SUMMARY...
A few strong thunderstorms are possible across parts of
northern/central Missouri and central Illinois today.
...Synopsis...
Early-morning satellite imagery shows broadly cyclonic flow across
much of the CONUS. The only exceptions are along the West Coast,
which is being influenced by an upper low just off the CA coast, and
the Southwest States, where minor shortwave ridging exists. A
low-amplitude shortwave trough is currently moving
southward/southeastward within this broadly cyclonic flow through
the Upper Midwest and northern Plains, with continued southeastward
progression expected throughout the period.
Recent surface analysis reveals a low over east-central MN, with a
cold front extending southwestward into south-central NE before
arcing back westward into far northeast CO and northwestward into
central WY. This surface low, which is associated with the Upper
Midwest shortwave trough, is forecast to progress eastward
throughout the day, while gradually weakening. As it does, the cold
front is expected to progress southeastward/southward, although the
western portion of the front will gradually slow and eventually
become stationary from southwest KS into northern MO this evening.
Ascent along and atop this frontal zone will be the focus for
potential isolated severe thunderstorm development this evening.
...Northern/central Missouri into central Illinois...
Some modest low-level moisture advection is anticipated across the
southern and central Plains today ahead of the southward progressing
cold front. However, any notable low-level moisture (i.e. 60+ deg F
dewpoints) will remain well south over south TX. This limited
low-level moisture coupled with strong heating and mixing, should
keep the airmass across the region capped through the afternoon and
into the early evening. Thereafter, strengthening warm-air advection
across the stalled front will combine with steep mid-level lapse
rates to support moderate buoyancy and limited convective inhibition
for parcels rooted around 700 to 800 mb. Cloud-bearing layer shear
is sufficient for organization of any deeper, more sustained
updrafts, and a few storms capable of isolated hail and/or damaging
gusts are possible.
...Northern California/southwest Oregon...
Thunderstorms are expected along the northern periphery of the upper
low off the central CA coast. Increasing mid-level moisture and cold
mid-level temperatures will support modest buoyancy amid moderate
easterly flow aloft, supporting the potential for small hail and
gusty winds with these westward progressing storms during the late
afternoon/early evening. Even so, overall severe coverage is still
expected to be less than 5%.
..Mosier/Dean.. 05/03/2026
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