Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Birmingham Alabama
526 PM CST Monday Dec 9 2013
for 00z aviation.
There is light at the end of this Tunnel of miserable wet weather
but first we will have to deal with another round of rain tonight.
A shortwave over the central and Southern Plains will round the
base of a larger trough tonight with forcing and isentropic lift
leading to the development of more Post-frontal rain. The rain
should move into the northwest counties around 03z and progress
through the County Warning Area on Tuesday morning. There will be a race between
the departure of the rain and colder air moving in across the
extreme northwest part of the County Warning Area. There is a slight chance that
temperatures could drop to or just below freezing (31-32f) right
at the very back edge of the rain between 09z-12z at the higher
elevations of Marion and Winston counties. Even with temperatures
near freezing at the surface...temperatures aloft will be way too
warm for snow or sleet. Confidence is too low to include a threat
of minimal accumulating freezing rain in the severe weather potential statement...but there is a
small chance of this occurring in the aforementioned locations.
As the shortwave progresses through the Ohio Valley it will cause
the front to surge southeastward on Tuesday with cooler and drier
air in its wake for Tuesday night. Temperatures on Wednesday and
Thursday mornings will drop well into the 20s for many spots.
Afternoon highs are expected to be in the 40s and 50s with mostly
sunny skies. The dry weather will continue into early Friday
before another weather system moves in from the west. Have
included likely probability of precipitation for Friday night into Saturday as models
are in decent agreement that a fairly significant rain event is
probable during that time frame.
00z taf discussion.
An impulse will cross the region tonight and tomorrow...and
rainfall will spread back into the area from northwest to
southeast. Given the moist ground conditions and isentropic
lift...low ceilings will continue tonight and patchy fog will be
possible. Will monitor trends this evening and might need to
adjust visible down...especially outside of the rain area. In
addition...northerly winds will increase and could be gusty at
times beginning early Tuesday morning. Will see some improvement
after 15z from west to east but will leave most areas in MVFR ceilings
based on length of tafs and slower tendency of the clouds moving