Day 1 Severe Weather Outlook

Valid 031200Z – 041200Z


Scattered to isolated severe storms are possible tonight mainly from
southwest through central Texas. A few severe thunderstorms are
also expected today and tonight from East Texas into the Mid South
and Southeast, and during the afternoon and early evening from
portions of the central Appalachians into the Mid-Atlantic region.

An upper trough centered across the mid and upper Mississippi Valley
early in the period is forecast to advance quickly across the Great
Lakes/Ohio Valley and into the Northeast through the day, and then
into/across the Northeast/New England overnight. Immediately behind
this feature, a second short-wave trough is progged to dig
southeastward out of the Canadian Rockies/northern Intermountain
region, shifting into the Upper Midwest late, and maintaining broad
cyclonic flow across much of the northern half of the U.S. through
the period. Meanwhile in the southern stream, an upper low will
move slowly eastward across northern Mexico, reaching the Texas Big
Bend area late. An area of short-wave troughing will precede this
feature, shifting across Texas and into Louisiana, while flat
westerly flow prevails across the Southeast where the confluence of
the northern and southern streams occurs.

…East Texas eastward into the Mid South/Southeast…
Showers and thunderstorms — and potentially an ongoing local severe
risk — will continue to spread eastward across the region, ahead of
the slowly advancing cold front. Weak height rises with time and
corresponding/weakening convergence along the front suggests that
severe risk should remain tempered, but maintenance of MRGL risk
seems justified. Overnight, elevated convection may develop over
portions of the Gulf Coast region, as low-level warm advection
increases over the western and central Gulf ahead of the upper low
shifting into West Texas. Marginal hail risk may accompany a few of
the stronger storms late in the period.

…Portions of western and central Texas…
As the upper low crosses northwestern Mexico and approaches West
Texas, showers and embedded thunderstorms will gradually spread
eastward across the middle and upper Rio Grande Valley. During the
evening, as the surface cold front begins to retreat as a warm
front, low-level destabilization and the increasing ascent should
yield an increase in convective coverage/intensity — particularly
across the Edwards Plateau area and into the Hill Country. Just
north of the warm front, risk for hail will prevail. Meanwhile,
some risk for strong/damaging winds or even a tornado may evolve
overnight, as strong southwesterly mid-level flow overspreads
low-level southeasterlies — providing favorable shear for rotating

…Parts of the central Appalachians to the Mid Atlantic region…
As a northern-stream upper trough moves quickly eastward across the
Ohio Valley region through the day, and approaches the central
Appalachians during the afternoon, modest/low-topped instability
should support convective development across parts of far eastern
Ohio/western Pennsylvania/West Virginia. Given strong/deep-layer
westerly flow, convection will be fast-moving — posing low-end risk
for locally strong/damaging wind gusts. The convection will move
quickly across Maryland/northern Virginia/eastern Pennsylvania
through early evening, likely diminishing gradually as it crosses
New Jersey and Delaware before midnight.

..Goss/Nauslar.. 03/03/2020


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