Day 1 Severe Weather Outlook

Valid 251200Z – 261200Z


Thunderstorms appear unlikely across the contiguous United States
today and tonight.

…Synopsis and Discussion…
An upper trough will amplify over the western states today as a
related 75-100 kt mid-level jet develops from the West Coast across
the Southwest and southern High Plains through the period. Strong
forcing for ascent will be present ahead of this trough across parts
of the Great Basin into the Four Corners region, and widespread
precipitation is expected. Although mid-level temperatures will cool
by this afternoon over these areas in advance of the upper trough,
instability is forecast to remain very meager (generally less than
100 J/kg of MUCAPE) owing to limited low-level moisture. The
probability of thunderstorms across this region today appears to be
less than 10%. Cold mid-level temperatures will also be present
beneath the upper trough across the Pacific Northwest, but
large-scale subsidence behind the passage of the upper trough axis
suggests limited potential for thunderstorms.

At the surface, lee cyclogenesis will occur across eastern CO late
tonight into early Tuesday morning as the upper trough over western
CONUS approaches the southern/central High Plains. Mass response at
low levels will encourage the northward transport of Gulf moisture
across parts of east TX into LA and AR today and tonight. Surface
dewpoints ranging from the mid 50s in central AR to near 70 F along
the coast of TX/LA will be present late in the period. Regardless, a
low-level temperature inversion along with negligible deep forcing
for ascent will likely preclude thunderstorm development across this
region through the end of the Day 1 period.

..Gleason/Nauslar.. 11/25/2019


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