RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0632 AM CST Wed Feb 18 2026
Valid 181300Z - 191200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe weather is not expected today or tonight.
...Discussion...
With an amplified large-scale pattern over the CONUS, an upper low
will continue to cross the Upper Midwest toward Lake Superior, with
preceding warm/moist advection and DPVA contributing to isolated
thunderstorms across parts of the Great Lakes region, mainly early
today.
In the West, a band of convection will continue to move inland early
this morning across coastal southern California in association with
a cold front. Diminishing convective potential is otherwise expected
today across most of California. However, isolated thunderstorm will
be possible later this afternoon and tonight across the coastal
Pacific Northwest and northern California as a secondary shortwave
trough digs southward along the coast. Isolated thunderstorms will
also be possible across the eastern Great Basin and central Rockies
mainly this afternoon. Here, sufficient diurnal mixing and a zone of
stronger mid-level southwesterly flow aloft could account for some
convectively enhanced wind gusts, but overall severe potential
should remain minimal.
..Guyer/Grams.. 02/18/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CST Wed Feb 18 2026
Valid 211200Z - 261200Z
...DISCUSSION...
Latest medium-range guidance indicates little further amplification
of large-scale mid-level troughing across the eastern mid-latitude
Pacific, but a broad embedded cyclonic circulation, with a number of
shorter wavelength perturbations pivoting around its periphery, may
continue to evolve through this coming weekend. These may be
accompanied by multiple areas of surface cyclogenesis, including one
cyclone with an occluding front which may advance into northern
Pacific coastal areas late Saturday night into early Sunday.
However, it appears that the coldest mid-level air, supportive of
boundary-layer based destabilization conducive to thunderstorms,
might remain offshore.
At the same time, downstream amplification of mid-level ridging may
continue across the Rockies and Great Plains Saturday into Sunday,
with subsequent amplification of troughing east of the Mississippi
Valley through areas offshore of the southern Atlantic Seaboard
Sunday through Monday. This is likely to be accompanied by cold
surface ridging building south-southeastward to the lee of the
Rockies, through much of the Gulf Basin, which probably will
suppress convective potential through the remainder of the period.
While the environment may be at least conditionally supportive of
strong to severe thunderstorm development along a frontal zone
across parts of the eastern Gulf Coast into southern Atlantic Coast
early this coming weekend, surface frontal wave development across
inland areas on Saturday is forecast to remain weak, tending to
minimize this potential.
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