ACUS01 KWNS 241232
SWODY1
SPC AC 241231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0631 AM CST Sun Nov 24 2024

Valid 241300Z - 251200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are unlikely through tonight.

...Synopsis/Discussion...
In mid/upper levels, a belt of relatively strong flow will bend
cyclonically from CA to the central Great Plains, changing curvature
through a low-amplitude, eastward moving synoptic ridge over the
Upper Great Lakes and Ohio Valley, then cyclonically again across
the Mid-Atlantic and New England.  A long-lasting, deeply occluded
cyclone will move eastward from the Canadian Maritime Provinces
through the period.  Upstream, a smaller cyclone -- initially
located over southern SK -- will move slowly eastward to southern MB
by 12Z tomorrow, with trough southward over the Dakotas.  However,
too little moisture will be available for a general thunderstorm
outlook.  Farther west, a synoptic-scale cyclone offshore from the
Olympic Peninsula and Vancouver Island will pivot slowly southward
then eastward through tonight, but will remain over Pacific waters.
Intervening ridging should remain over the northern Rockies and
vicinity.  However, cold air aloft and steep low/middle-level lapse
rates will overlie a moist marine layer, supporting isolated to
widely scattered, episodic thunder mainly offshore.  Some of this
activity may move inland before dissipating in more-stable low-level
conditions.

A shortwave trough -- evident in moisture-channel imagery south and
east of the ridge from the Yellowstone region across the northern
Great Basin to central CA -- is forecast to move quickly eastward
across the central Rockies and central Plains through the period,
phasing with the SK/MB low by 12Z tomorrow.  The associated cold
front was drawn at 11Z today across an area of low pressure
extending from northeastern NE to southwestern KS, then arching over
southeastern CO.  A warm front was drawn over southeastern KS and
southwestern MO, with a secondary warm front over southern IA and
northern IL.  The low should consolidate today across northeastern
KS into northern MO, and move to near the southwestern shore of Lake
Michigan by the end of the period, when the cold front reaches to
near a line from BMI-STL-FSM-SPS-HOB.  Scattered elevated showers
are possible late tonight near and north of the warm front, across
parts of northeastern IL, WI, Lower MI, IN, and OH.  However, the
warm conveyor will lack rich moisture, and forecast soundings
reasonably suggest buoyancy will be too shallow and strongly capped
for an areal thunderstorm threat.

..Edwards/Leitman.. 11/24/2024

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