SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0652 AM CST Fri Feb 18 2022
Valid 181300Z - 191200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunderstorms are possible today from the coastal Carolinas
to northern Florida.
...Synopsis/Discussion...
In mid/upper levels, mean troughing will persist from the Canadian
Arctic Islands and Hudson Bay to the east-central CONUS through the
period. Initially, a positively tilted trough and associated
lengthy vorticity banner were apparent from southern ON across parts
of the Ohio Valley to the Ozarks, northwest TX and northwestern MX.
This feature will elongate further and weaken, with its northern
portion moving offshore from New England and the Mid-Atlantic, while
the southern part slowly loses definition within a broad cyclonic-
flow field. A trailing/northern-stream shortwave trough -- evident
in moisture-channel imagery from southern MB to northwestern MN --
will reach southeastern ON and southern Lower MI by 12Z tomorrow.
At the surface, 11Z analysis showed a cold front across portions of
New England, the near-coastal Mid-Atlantic, central VA, western SC,
the west-central FL Panhandle, and the north-central/west-central
Gulf. This front will move offshore from all but northern FL by
03Z, then southeastward to south-central FL by 12Z. Isolated
thunderstorms will remain possible in a narrow band of mostly
prefrontal convection now located from coastal NC to the eastern FL
Panhandle. With nearly front-parallel flow aloft, poor mid/upper-
level lapse rates, weakening large-scale to frontal-scale lift, and
veering prefrontal surface winds with time, severe potential appears
minimal, despite lingering strong flow aloft.
In the continental/polar air mass behind that cold front, another
low (associated with the MB/MN perturbation aloft) was drawn over
extreme southern MB, with cold front across northern parts of ND/MT.
The latter front is forecast to sweep southward/southeastward over
the Upper Midwest, Great Lakes and lower/middle Missouri Valley, to
near the Ohio Valley by the end of the period. Dry/stable low-level
conditions in the prefrontal sector will prevent associated
thunderstorm development.
..Edwards/Gleason.. 02/18/2022
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