SHORT TERM [Monday Through Tuesday Night]...
On Monday, a cold front will approach the area from the northwest,
but should take until the late afternoon to make it to SE Alabama.
The front will then push through the remainder of the area on
Monday Night as it begins to stall from the central Gulf of Mexico
to just offshore of the Carolinas. This timing supports highest
PoPs in the northwestern portion of our area, and from the mid
afternoon through the evening. The cold front will be taking on an
increasingly negative tilt in the vertical (sloped back towards
the northwest) with time, as the shallow cooler air mass near the
surface is advected south to the coasts. This should lead to
weaker low-level forcing by Monday Night, and mainly post-frontal
light rain showers.
The latest SPC SWODY2 has a "slight risk" of severe thunderstorms
just northwest of our area for Monday, with lower probabilities to
the east. There will be an abundance of deep layer (and low-level)
shear across the region, but the primary convective ingredient
that is in question is instability. The mean CAPE on convection
allowing models is only around 300-500 j/kg in the western part of
our area, and forecast soundings reveal fairly weak lapse rates.
Additionally, there may be an abundance of low-mid level cloud
cover that could limit insolation across parts of the area. Thus,
the overall probability of severe weather seems low, although a
strong storm may be possible in our SE Alabama counties late.
Forecast soundings for Tuesday across most of the area show a
pronounced frontal inversion around 900mb in the wake of the
surface cold front, with a fairly moist column. Therefore, it
looks like a cloudy, cool day with northerly winds. The NAM shows
some modest vertical motion coinciding with a saturated layer near
the frontal inversion, which could produce drizzle and light rain
showers. By Tuesday Night, the approach of a digging shortwave at
the base of the broader trough should provide sufficient deep
layer forcing for more widespread rain overnight.