Day 1 Severe Weather Outlook

Valid 280100Z – 281200Z


The risk for severe thunderstorms appears negligible across the U.S.
through tonight.

…01Z Outlook Update…

…Southern Plains…
Modest lower/mid tropospheric cyclogenesis appears underway across
the Texas Panhandle vicinity. This appears likely to proceed with
the cyclone migrating southeastward into northwest Texas overnight,
as strongest mid-level height falls associated with an amplifying
short wave trough shift from the lee of the southern Rockies through
the Texas Big Country. Models indicate that some further
strengthening of southerly 850 mb flow (to 30 kt) is possible
within the warm sector, across and west of the I-35 corridor of
Texas by late this evening. However, inland moisture return off the
western Gulf of Mexico remains limited, with surface dew points
inland of the lower/middle Texas coast still only in the mid 50s to
lower 60s F.

Still, a plume of mostly elevated moisture return characterized by
precipitable water of .5-.75 inches, currently extends across Deep
South Texas and the I-35 corridor of central Texas, into
southwestern Oklahoma. In the presence of steepening lapse rates,
this probably will contribute to sufficient destabilization for at
least scattered, generally weak thunderstorm development tonight.
This should be rooted within and aided by forcing for ascent
associated the low-level warm advection, particularly across parts
of southwestern and south central Oklahoma into north central Texas
by around 05-06Z.

Otherwise, at least attempts at high-based thunderstorm development
appear ongoing west and southwest of San Angelo TX, aided by forcing
for ascent ahead of the approaching short wave trough. As this
forcing and convection encounter the better low-level moisture
return, thunderstorm probabilities are expected to increase across
the Edwards Plateau and Hill Country, toward the I-35 corridor,
through 03-09Z.

…Pacific Northwest…
Thermodynamic profiles conducive to convection capable of producing
lightning appear likely to remain confined to beneath the mid-level
cold pool (including 500 temps at or below -28C) of the approaching
short wave trough. The leading edge of this air mass is generally
forecast to begin spreading inland of Washington and Oregon coastal
areas after around 08Z.

..Kerr.. 01/28/2020


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