SPC AC 020710
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0110 AM CST Thu Dec 02 2021
Valid 041200Z - 051200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Weak thunderstorm activity is possible Saturday through Saturday
night in a corridor across the southern Great Plains into the Mid
South.
...Synopsis...
Downstream of amplified troughing (including a number of embedded
perturbations) within the split westerlies across the eastern
Pacific, models indicate that mid/upper ridging will build along an
axis from the lower latitudes into areas near or just west of much
of the North American Pacific coast. Downstream flow appears likely
to take on more of a northwesterly component across and east of the
Canadian/northern U.S. Rockies, with one significant short wave
impulse on the leading edge of this regime digging into the northern
U.S. Great Plains by late Saturday night. This is forecast to be
accompanied by at least modest surface cyclogenesis, while cold
surface ridging, initially encompassing much of the northern/central
Great Plains and upper half of the Mississippi Valley at the outset
of the period, rapidly shifts to the Atlantic Seaboard in the wake
of a preceding short wave trough.
In lower latitudes, perturbations emerging from mid/upper troughing,
within a weak branch of westerlies emanating from the subtropical
eastern Pacific, appear likely to continue migrating eastward across
parts of the Southwest into southern Great Plains and Gulf Coast
states Saturday through Saturday night. In addition to continuing
elevated moisture return from the subtropical Pacific, a southerly
return flow of moisture off a modifying western Gulf of Mexico
boundary layer is forecast to persist across the lower Rio Grande
Valley through parts of the southeastern Great Plains into Mid
South. It appears that the low-level moisture return will be
gradually undercut by a weakening cold front on the leading edge of
remnant shallow cold air, which may continue to advance
southward/southeastward across parts of the Mid South and southern
Great Plains through late Saturday night.
...Southern Great Plains into Mid South...
Weak mid-level destabilization, associated primarily with the influx
of the Pacific moisture, may continue to support a risk for
scattered weak thunderstorms across parts of the southeastern Great
Plains and Mid South into the day Saturday. Later Saturday into
Saturday night, it appears that Gulf moisture return above the
southward advancing cold front might be the primary contributor to
destabilization supportive of scattered weak thunderstorm
development, downstream of a short wave trough progressing across
and east-southeast of the southern Rockies.
..Kerr.. 12/02/2021
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