SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1118 AM CST Sun Feb 12 2023
Valid 131200Z - 141200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for severe thunderstorms appears negligible across the U.S.
Monday through Monday night.
...Synopsis...
Models indicate that mid-level ridging centered over the southern
mid-latitude eastern Pacific may become a bit more suppressed during
this period, as short waves begin to a amplify within a prominent
belt of westerlies on its northern periphery. Near the leading edge
of this regime, it appears that digging larger-scale mid-level
troughing will evolve across the Pacific Northwest through northern
Great Basin vicinity, as a couple of smaller-scale perturbations
progress inland downstream of building mid-level ridging near 140W.
As this occurs, a significant mid-level low, initially migrating
northeastward near the western Sonora/Arizona border, is forecast to
accelerate across the southern Rockies into the southern Great
Plains by late Monday night. Downstream, a preceding mid-level low
emerging from the Southwest likely will accelerate
east-northeastward, away from the Mid Atlantic coast, ahead of
another short wave trough digging east-southeast of the Upper Great
Lakes region.
In response to these developments, a cold front, trailing the
surface cyclone accompanying the lead mid-level low, is expected to
stall and weaken across the Bahamas/Caribbean/into western Gulf of
Mexico vicinity. And the center of cold surface ridging likely will
shift from the northern Gulf coast vicinity into the Southeast,
while surface troughing deepens to the lee of the Rockies. A
moistening boundary layer over the western Gulf of Mexico will begin
to advect northward on a developing southerly return flow. However,
in the wake of the recent cold intrusion, boundary-layer moisture
characterized by surface dew points in excess of 55 F may not reach
areas north of Deep South Texas until Monday night, and it appears
that this will be mostly beneath warm, dry and capping lower/mid
tropospheric layers.
...Pacific Coast into Great Plains...
Weak destabilization beneath mid-level cold pools, including 500 mb
temperatures near or below -30C, may contribute to scattered
convective development which may become capable of producing
lighting across parts of the Pacific Northwest, and the Southwestern
Deserts into the southern Rockies Monday into Monday night.
East of the Rockies, it appears that warm, dry lower/mid
tropospheric layers will largely inhibit thunderstorm development in
association with the boundary-layer moistening accompanying the Gulf
return flow. Based on NAM and Rapid Refresh forecast soundings, the
extent to which moistening (of lower latitude eastern Pacific
origins) aloft can contribute to destabilization supportive of
convection capable of producing lightning also remains rather
unclear. At this point, forecast soundings which might become
marginally conducive to scattered weak thunderstorm development seem
mostly confined to portions of the Texas South Plains and Big
Country, near the leading edge of the stronger mid-level forcing for
ascent and cooling associated with the low emerging from the
Southwest.
..Kerr.. 02/12/2023
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