Area Forecast Discussion
Issued by NWS Birmingham, AL

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889
FXUS64 KBMX 082315
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
515 PM CST Thu Dec 8 2016

.UPDATE...
For 00Z Aviation.

&&

.DISCUSSION...

Weak upper level energy crossing Central Alabama today has
resulted in mid to high level clouds across the area. This is
ahead of a strong surface ridge spreading southward from central
Canada through the Plains. Strong cold advection will continue
tonight with temperatures falling into the lower 20s north to
around 30 south. Due to the tightened pressure gradient, winds
will remain breezy overnight. This will bring wind chill values
down into the teens early tomorrow morning. If you must be outside
for several hours before and after sunrise, be prepared to bundle
up. It could be at late as 10-11AM tomorrow morning before temps
rise above freezing across the far north. It will be a struggle
to warm above 40F in the north tomorrow afternoon, with mid 40s in
the south.

The surface ridge spreads across the Tennessee Valley Friday and
Friday night. Winds will diminish, and with clear skies, overnight
lows will again fall into the 20s. Would not be surprised if
typically colder locations fall into the upper teens Saturday
morning. Temps do moderate Saturday as low level winds become
easterly and then southeasterly, and afternoon highs warm into the
mid 40s north to mid 50s south.

Ahead of a shortwave/frontal system crossing the Central Plains
Sunday, winds will become southerly, but it will take some time
for moisture to return to the area and will keep only a slight
chance of rain in the far northwest Sunday afternoon. By the time
deeper moisture arrives, better forcing associated with the
shortwave is pulling out of the area. Will mention likely pops
across the north and chance elsewhere as the front pushes
southward through the area on Monday.

Beyond Monday, model solutions vary from 24hrs ago in the
progression and strength of the next system affecting the area
midweek. Rather than the southern end of a northern stream system
bringing a weak front and rain chances to the area, the wave
pattern remains progressive and a shortwave picks up the previous
front, bringing it back north Tuesday night. As a surface low
develops along the front, rain returns to the area Tuesday night
through Wednesday. This would be a warmer, yet wetter, solution
than the previous forecast, and will increase pops for several
periods in the extended to account for these new trends.

14


&&

.AVIATION...
00Z TAF Discussion.

Northerly winds to persist for the period, although calming to
less than 5 kts by 03Z at most sites. Winds will pick back up
after 15Z with generally 10 to 12 KTS expected. Otherwise VFR
conditions are expected.

16

&&

.FIRE WEATHER...

Much colder air will move into the area tonight and be present
through Saturday. Relative humidity values will drop below 25
percent Saturday afternoon for portions of the area for a couple
of hours. However, winds are expected to be light. Moisture begins
to increase Saturday night with rain chances returning late Sunday
into Monday. While the best chances will be Sunday night into
Monday, rain chances will remain a possibility through the middle
of next week as we will be affected by multiple surface fronts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     21  41  18  47  27 /  10   0   0   0   0
Anniston    24  42  21  50  30 /  10   0   0   0   0
Birmingham  25  41  23  49  33 /  10   0   0   0   0
Tuscaloosa  26  43  21  50  30 /  10   0   0   0   0
Calera      25  43  22  50  32 /  10   0   0   0   0
Auburn      28  45  26  50  35 /   0   0   0   0   0
Montgomery  28  48  26  54  32 /   0   0   0   0   0
Troy        28  47  24  52  31 /   0   0   0   0   0

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
None.

&&

$$



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