SPC 0700Z Day 2 Outlook

Day 2 Outlook Image

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1259 AM CST Thu Dec 03 2020

Valid 041200Z - 051200Z


Isolated severe thunderstorms are possible portions of the Florida
Panhandle Friday afternoon, and across the coastal Carolinas early
Saturday morning.

A positively tilted shortwave trough is forecast to extend from the
middle OH Valley into north TX early Friday morning. This shortwave
is then expected to progress quickly eastward while pivoting to a
neutral and then negative tilt. By early Saturday morning, the
expectation is for this shortwave to be over the Mid-Atlantic

Surface low associated with this shortwave will likely be centered
near coastal MS/AL early Friday morning before quickly moving
northeastward into the Mid-Atlantic ahead of its parent shortwave.
As it does, an attendant cold front will sweep
eastward/southeastward across eastern portions of the Southeast, the
FL Panhandle, and much of the Mid-Atlantic. Two areas of potential
severe weather are possible, one across the FL Panhandle Friday
afternoon and the other over the central and eastern Carolinas early
Saturday morning.

...FL Panhandle...
Low to mid 60s dewpoints are expected to be in place ahead of the
cold front Friday morning into Friday afternoon. Abundant cloud
cover is expected, tempering daytime heating, and lapse rates will
be poor. Consequently, despite favorable low-level moisture,
instability will be modest (i.e. MLCAPE less than 750 J/kg). Most of
the better flow aloft and vertical shear will be displaced north of
any instability and/or behind the front. However, there appears to
be a relatively narrow window where instability and vertical shear
will overlap enough to promote at least low-probability severe
potential across the western/central FL Panhandle Friday afternoon.
In this area, any more robust and persistent updraft could produce
an isolated damaging wind gusts and/or brief tornado.

The shortwave is expected to mature as it continues eastward into
the Mid-Atlantic region, with this maturation contributing to an
increase in low to mid-level flow throughout its eastern periphery.
This enhanced flow aloft will spread into the central and eastern
Carolinas from 06Z to 12Z Saturday. Additionally, favorable onshore
trajectories will result in modest moisture advection, with
dewpoints likely in the low to mid 60s. As a result, there will
likely be enough instability and shear for a few supercells ahead of
the front, as well as strong storms along the front. Damaging wind
gusts appear to be the greatest threat, but a tornado or two is also
possible. Higher wind probabilities may be needed in later outlooks
if the probability for slightly greater instability increases.

..Mosier.. 12/03/2020

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