- Day Three
acus03 kwns 170735
Storm Prediction Center ac 170734
Day 3 convective outlook
National Weather Service Storm Prediction Center Norman OK
0134 am CST Thu Jan 17 2019
Valid 191200z - 201200z
..there is a marginal risk of severe thunderstorms across parts of
Louisiana...Mississippi...Alabama and the Florida Panhandle...
At least isolated severe storms are expected across parts of the
Gulf Coast states on Saturday, with wind damage the most likely
..synopsis and discussion...
A powerful shortwave trough will move rapidly eastward across the
Gulf Coast states with low pressure moving from Arkansas at 12z Saturday
to Virginia by 12z Sunday. Southerly winds ahead of a cold front will
result in modest low-level moistening with lower 60s f dewpoints
expected across southern la, MS, Alabama and the Florida Panhandle.
Destabilization will be driven mainly by moisture advection and
cooling aloft, with the primary severe threat related to storms
along the cold front. MLCAPE values are forecast to be generally at
or below 500 j/kg, but 850 mb winds will exceed 50 kt, resulting in
favorable low-level shear for qlcs structures assuming sufficient
instability. Thus, damaging winds appear to be the main threat, with
perhaps a brief/weak tornado especially if pockets of greater
instability can develop. In any case, severe probabilities may
increase in later outlooks as details become more predictable.
Elsewhere, mid 50s f dewpoints are expected to move onshore across
eastern NC Saturday night in advance of the cold front. Widespread
precipitation will occur here as well, along with strong low-level
shear. An isolated severe risk cannot be ruled out here as well, but
will also depend on boundary layer stability.