Day 1 Severe Weather Outlook

Valid 201200Z – 211200Z

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE OH VALLEY INTO WESTERN NEW ENGLAND AND OVER THE GULF
STATES…

…SUMMARY…
Isolated strong to severe storms capable of producing mainly wind
damage may occur across parts of the Ohio Valley into the
Mid-Atlantic and Northeast. Isolated strong to severe storms are
also possible across portions of the Southeast states.

…Oh Valley to Western New England…

Short-wave trough over the Mid-MS Valley will translate across the
Great Lakes by 18z and suppress heights as far south as the northern
Middle Atlantic region. At the surface, primary wind shift will
progress across the OH Valley to a position from western NY-central
OH-western KY by early afternoon. Dew points have steadily risen
into the mid 50s-60F across the warm sector as far north as western
PA early this morning and this air mass should advance into NY prior
to frontal passage. Very strong wind fields will overspread the OH
Valley into New England ahead of the trough with LLJ forecast to be
on the order of 70kt across western PA at the beginning of the
period. While forecast soundings do not exhibit appreciable
instability, there is some concern that any convection that develops
along/ahead of the wind shift may produce locally severe wind gusts.
However, latest CAMs do not suggest organized convection will
develop along the boundary and it’s not entirely clear how
significant the shallow convection will be in the absence of strong
forcing and veered low-level flow. Until it becomes more clear that
buoyancy will support robust updrafts an upgrade to SLGT Risk is not
warranted. If/when this occurs a SLGT Risk could be issued to
account for a potentially more aggressive squall line that could
produce damaging winds.

…Gulf States…

Low-latitude short-wave trough is currently ejecting across northern
Mexico into south-central TX. This feature will de-amplify as it
translates into the Mid-South region by 21/00z. Scattered convection
is expected to develop ahead of this feature with significant
coverage likely evolving along/north of the wind shift as it moves
southeast across the lower MS Valley. Low-level convergence should
remain weak across the Gulf States with negligible LLJ influence and
moist-adiabatic lapse rates. Forecast soundings do not exhibit much
instability but strong mid-level flow does warrant some risk for
storm organization. Will maintain 5% severe probs to account for
some damaging wind potential with frontal convection.

..Darrow/Squitieri.. 03/20/2020

$$

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