Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Birmingham Alabama
111 PM CDT Sat Mar 15 2014
Overall forecast generally on track this afternoon. Not expected a
great amount of rainfall until after dark...so left the 20-30 probability of precipitation
mainly southwest. Increased the temperature trend slightly but
clouds should hold the highs where they were originally forecast.
18z taf discussion.
Storm system approaches the area the next 24 hours. Slowly
decreased ceilings with MVFR around 06z...then IFR just after 12z.
This will coincide with rain shield developing west and south and
encompassing the area by 12z. There will be a chance that some
gusty winds will be realized near stronger convection and possibly
with a wake low developing around 12z. Rain and possibly some
thunder will remain across central Alabama until 18z or so but had
too many lines in tafs.
/issued 356 am CDT Sat Mar 15 2014/
Much warmer temperatures overnight than the last couple of nights.
At 3 am...temperatures are generally in the low to middle 50s across
central Alabama. The surface high is now to the east and southerly
flow has kept temperatures up tonight. The current upper level
pattern is characterized by rather zonal flow across the southeast.
Further to the west...an upper level trough is pivoting across the
Desert Southwest and another upper level trough can be noted moving
southeastward across the northern rockies. These two features will
be the main players in bringing in the widespread rain expected
overnight tonight and into Sunday. At the surface...a low pressure
center is currently located across central Texas with a cold front
stretching southward into southern New Mexico. For today...expect
conditions will be mostly dry across the County Warning Area with a few exceptions.
Continued warm air advection and isentropic uplift will bring in the
chance for a few scattered showers today. However...expect rain will
hold off for much of the day with best chances coming during the
afternoon hours. Most of the models have backed off on the
precipitation today and haven't seen much indication in the hi-res
models of much precipitation today.
The surface low currently across central Texas will track eastward
with deep moisture advection. Precipitable water values will increase to 1.25-1.50
inches tonight with widespread precipitation expected. Model
soundings indicate that the middle-level lapse rates will be near or
slightly greater than moist adiabatic...therefore...we could hear a
few rumbles of thunder overnight. Widespread precipitation will
continue into Sunday morning as the trough currently across the
north rockies phases with the trough further to the south. The
models indicate a dry slot will move into the area Sunday afternoon
and expect a brief break in the precipitation...however...a few
scattered thunderstorms could still be possible. Instability and
shear values remain too low to support any severe weather. A few
strong storms could be possible across the south where the
instability will be the best. Models continue to favor a closed
upper level low as trough progresses to the east. With this
scenario...rain chances will continue on Monday and into Monday
night. The latest suite of models have continued to indicate this
solution and have increased probability of precipitation during this timeframe. Rainfall
totals across the area look to be somewhere in the 1 to 2 inch
range with this event. Due to the duration and recent dry
weather...do not expect any flooding issues at this time.
Dry air finally moves into the area on Tuesday throughout the
remainder of the work week. The European model (ecmwf) indicates a bit of light rain
on Wednesday with a weak cold front but have kept the forecast dry
for now. Models indicate that temperatures should be near
climatological averages throughout the work week.
Preliminary point temps/pops...
Gadsden 71 56 66 50 57 / 10 100 100 70 60
Anniston 69 56 68 52 60 / 20 100 100 70 60
Birmingham 69 56 70 49 56 / 20 100 100 70 50
Tuscaloosa 70 57 75 47 57 / 20 100 100 70 50
Calera 69 56 71 51 59 / 20 100 100 70 50
Auburn 68 54 67 56 61 / 20 80 100 80 60
Montgomery 71 59 72 56 64 / 20 90 100 80 60
Troy 72 58 71 58 66 / 20 80 100 80 60