Scientific Forecaster Discussion

Return to Local Conditions & Forecast
Area forecast discussion 
National Weather Service Birmingham Alabama
1033 am CDT Thursday Apr 24 2014

Update...
morning update.

&&

Discussion...

Another warm day expected across central Alabama with high
temperatures reaching up into the low to middle 80s. An upper level
trough is currently moving across the central and Southern Plains.
At the surface...a low is currently located in southeastern
Kansas. A warm front extends southward from the low and is
currently located across southern portions of the forecast area.
This front is expected to move northward today with moisture
increasing across the area. Thunderstorms have developed along
this warm front further back to the west across western Arkansas
and will continue to move eastward today. The upper level trough
is a bit stronger than the models previously indicated and with
warm and moist boundary layer across the middle-Mississippi River
valley...a slight risk for severe storms has been issued. The
atmosphere over central Alabama is a bit more stable and don't
expect any thunderstorms to move into the area until the 03-06z
timeframe. Therefore...with the loss of heating...expect storms will
be weakening significantly as they move into northwestern portions
of central Alabama. Only major update was to decrease dewpoints
throughout the morning with the warm front being slow to lift
northward.

05/Massachusetts

&&

Aviation...
12z taf discussion.

Patch of middle-level cloudiness (bases above 5000 ft) will spread
northward across the area through the rest of the morning hours.
Conditions are expected to remain VFR until at least after sunset
this evening. Computer model moisture profiles do suggest some low
level moisture spreading in after that time...and have introduced
some MVFR ceilings. There's bound to be a few showers around
tonight...but confidence is not high enough at this time to go
with anything more than vcsh in the northern group of taf
locations.

/61/

Note...the National Weather Service is now issuing seasonal
terminal forecasts for the Talladega Municipal Airport (kasn) in
Talladega...Alabama. The forecasts will be issued through at least
may 8th 00z. Due to the limited availability of observations...
kasn taf will have amend not schedule appended to the end of the forecast.



&&

Previous discussion...
/issued 348 am CDT Thursday Apr 24 2014/
short term...today through Saturday.

A chilly start to the morning across areas north of I-20 where
temperatures are in the 40s. A stalled out surface front across
south central Alabama will shift northward today as low level
winds become southerly. Surface dewpoints will climb rapidly across
West Alabama this afternoon with some lower 60s possible across the
southwest counties by late afternoon. A fast moving short wave
trough will approach northwest Alabama this evening. The models are
trending towards a slightly higher amplified trough and stronger
forcing than previous runs. With surface dewpoints forecast to
climb to near 60 degrees across Mississippi this afternoon and
temperatures in the lower 80s...instability will be high enough for
a few strong to possibly severe storms across northern
Mississippi...and the Storm Prediction Center has expanded the
slight risk into extreme northwest Alabama. By the time the line of
storms reaches Marion and Lamar counties...boundary layer
temperatures will have had enough time to cool to keep
thunderstorms below severe limits...but a few may be locally
strong. Most of the rain tonight will stay across the northern
half of Alabama...closer to the best large scale lift. A surface
front will push into northwest Alabama around sunrise Friday and shift
quickly southeast. Any remaining showers along the front will
likely dissipate during the morning hours as the upper level
support pulls away from the region. As a strong storm system moves
into the plains states on Saturday...and upper ridge will build
downstream over the southeast states...and rain free conditions
expected Friday night and Saturday across central Alabama. Surface
temperatures will be much warmer on Saturday under the ridge.

58/rose

Long term...Sunday through Wednesday.

Sunday will be a day of transition across Alabama as the first of
several waves of convection rotates across the central Gulf Coast
states. No organized convection expected to impact central Alabama
Sunday or Sunday night...although a few storms could develop Sunday
afternoon and evening across West Alabama. The latest GFS model is
showing an mesoscale convective system moving across northern Mississippi Sunday night and
into north Alabama Monday morning. This is the only model run to
show organized convection that far east by early Monday...and will
lean towards the slower solutions provided by the European model (ecmwf) and
Canadian models. The first wave of severe storms could impact
west central Alabama Monday afternoon...but the primary threat
time for severe storms still looks like Monday night and early
Tuesday...with all modes of severe weather possible. Since the
line of convection is forecast to be parallel to the upper level
flow...there will be the potential for periods of heavy rainfall
and flash flooding as cells train over the same areas. After the
main band of convection shifts out of east Alabama Tuesday morning
.The models are showing a zone of strong warm air advection
across east Mississippi and West Alabama Tuesday afternoon ahead
of the main front. The big uncertainty is how much low level
moisture will still be available at that time. The GFS model is
forecasting a zone of middle 60 surface dewpoints ahead of the front.
If the air mass can recover from morning storms...there could be
some isolated severe storms across the western counties in the
afternoon.

The severe threat should diminish Tuesday evening as the air mass
cools...but there will be a chance of showers and thunderstorms
Tuesday night as the main front moves across the area. Cooler on
Wednesday with a chance of showers...mainly across north Alabama.

58/rose

&&

Bmx watches/warnings/advisories...
none.

&&

$$