
Area Forecast Discussion
National Weather Service Birmingham AL
328 AM CDT Thu Apr 23 2020
.SHORT TERM...
/Updated at 0327 AM CDT Thu Apr 23 2020/
Well here we are, the event is upon us and there are still some
uncertainties in place. The good news is that most of the model
solutions have a good handle on the timing through the afternoon.
Provides a little more confidence on the system moving through
and exiting later this evening. Could still see some wrap around
rain and perhaps a thunderstorm through Midnight in the east.
Questions for the forecast that still have not really been
resolved is the severe potential. There is still quite a bit of
concern on how much of the instability can actually be realized
and how far north will the actual potential be. Some of the more
robust and convective enhanced models are placing much of the
south and east in a very high range for CAPE and overall
instability. Other solutions, which have handled the last several
events quite well, continue to keep the best dynamics well in our
southeast through the afternoon.
So let`s take a look at the overall evolution of the pattern. We
are currently seeing round one moving into the area. A few
stronger storms have already impacted far southwestern counties
with additional storms moving in shortly. This first wave will
slide east through the morning and should in our eastern counties
by late morning. Right now we only have elevated storms associated
with the activity as the warm front is still to our sw. Right now
we are concerned with any activity that may move into or develop
near the US 80/ I-85 corridor through the morning for damaging
straight line winds and hail through 10 AM. The chance for a
tornado remains low until the front get closer to the region, so
later this morning.
As this wave moves out, there will be somewhat of a lull in
activity as the warm front continues to lift northward and the
cold front approaches the area. This is where the forecast begins
to get a little a tricky. There should be some clearing in the
southwest and temperatures will try to climb into the upper 70s as
a strong southwesterly wind increases over the area. The problem
here will be how far north will the richest airmass work before
the cold front moves through. That is where the models begin to
differ and thus a very wide range of available CAPE for
instability. At this time the threats will be from Noon to 7 PM
with the front, while the potential increases the further east you
get. The highest potential for severe weather will be generally
along and south of the I-20 corridor through the afternoon. As we
move through the day several meso-scale updates will be done as
the information becomes available and will adjust the timing as
needed.
Once the front works through, we will see the upper level feature
work through across the north. This will generate some lighter
rain into the evening hours across the north. Any precipitation
should be done and out of the area by 4 AM. Lows overnight will
drop into the 50s.