Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Birmingham Alabama
1053 PM CDT Tuesday Sep 30 2014
The forecast is on track this evening. There are a few middle to high
clouds moving across northern Alabama associated with a weak upper
level disturbance. Patchy fog is already being observed across
Georgia and expect this will be the case across eastern portions
of the state over the next couple of hours. Made slight
adjustments to the hourly temperature and dewpoint grids but no
other changes were made.
00z taf discussion.
Expect patchy fog tonight with MVFR visible possible between 08z and
14z. Some guidance indicating there could be a brief period of IFR.
Most likely location for this would be toi where dewpoints are
slightly higher than other locations. Will monitor cooling trends
this evening...and asses whether changes to the current forecast are
Note...the National Weather Service will begin issuing seasonal
terminal forecasts for the Talladega Municipal Airport (kasn) in
Talladega...Alabama. The forecast will begin October 5th at 00z
and last through at least the 23rd of October.
/issued 402 PM CDT Tuesday Sep 30 2014/
Most of the low clouds have finally mixed out across central
Alabama...with the exception of Troy and Eufaula. Even those
locations will see clearing throughout the remainder of the
afternoon and into the evening. Patchy fog and low clouds will be
possible again tonight generally along and south of I-59 as
weak isentropic lift is being advertised by short range guidance.
Dry and warm conditions will continue through the remainder of the
week with temperatures 6-10 degrees above normal for this time of
the year Wednesday afternoon and Thursday afternoon. Increasing
clouds are expected on Thursday ahead of the strong storm system
that will give US a chance of at least isolated severe storms late
Thursday night through early Friday morning.
We're still expecting a strong shortwave to push across the Southern
Plains states during the day on Thursday that will help to dig the
main longwave trough southward. That shortwave will be our concern
in regards to severe storms...as we'll see a low level jet of around
25-30 knots at 925mb moving in late Thursday night into early Friday
morning. The low level jet will transport rich Gulf moisture
northward with dewpoints in the upper 60s to lower 70s. Bulk shear
values and upper level divergence will be the highest closer to the
actual shortwave that will move quickly across Arkansas and western
Tennessee early Friday morning. Therefore...the forecast hasn't
changed this afternoon in regards to the areas highlighted that will
have an opportunity for severe storms which includes much of the
northern half of central Alabama. Although helicities remain
marginal at this time...we'll have to watch for any increase in the
low level jet as that could increase the chance of isolated
tornadoes in addition to the greatest threat of damaging
straight-line winds. The threat will begin just after midnight for
the northwest counties and last as late as 11am in the east and
northeast counties. We're not expecting any widespread flooding with
this system due to the dry conditions but some very heavy rainfall
could fall in a very short amount of time and cause problems for
poor drainage areas.
The cold front is still expected to push through all of central
Alabama by Friday evening...with much drier and cooler air moving
in. Guidance is actually cooler in regards to highs on Saturday and
lows Sunday morning and i've gone ahead and trended in the cooler
direction as well. Upper 60s for highs are now being advertised for
our northern counties...with lower 70s possible elsewhere Saturday
afternoon. Lows Sunday morning will be in the 40s for many areas
which will be the first crisp morning of this fall season.
Moderating temperatures with dry weather is expected to continue
through much of next week.
Preliminary point temps/pops...
Gadsden 57 86 61 87 69 / 0 0 0 30 80
Anniston 60 86 65 87 70 / 0 0 0 30 60
Birmingham 62 87 68 87 71 / 0 0 0 40 80
Tuscaloosa 62 89 67 88 71 / 0 0 0 50 80
Calera 64 87 67 87 70 / 0 0 0 40 70
Auburn 64 85 66 86 70 / 0 0 0 20 40
Montgomery 65 88 68 89 71 / 0 0 0 40 40
Troy 63 87 65 88 71 / 0 0 0 30 30