Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 081730

Area Forecast Discussion
National Weather Service Birmingham AL
1130 AM CST Thu Dec 8 2016

For 18Z Aviation.


Today and Tonight.

A cold front is stretched across Northern and Central AL this
morning. Moisture profiles in the area remain dry, and precipitation
has failed to materialize thus far, so I have lowered the PoPs for

Behind the cold front, gustier winds with cooler temperatures can be
expected. Surface ridging originating in central Canada slides into
the Southeast CONUS during the day, bringing in the colder air mass.
Highs in the northern counties will only reach the low 40s today.
For the southern counties, the front and associated cloud cover
lingers into the afternoon hours allowing temps to stay in the low
50s before dropping after sunset. By early Friday morning, the
cooler temperatures have fully set in across Central AL., with
lows being 20-30 degrees area-wide (the lowest temperatures being
in the northern counties). NOT expecting to meet criteria for a
Hard Freeze, which requires 15 degrees or below to be in the
forecast for several locations. The other story for the day will
be the winds, which will be in the 10-15 mph range. Winds chills
drop below 32 in the early evening tonight and continue to drop
overnight with the colder temperatures sinking in. By early Friday
morning, wind chills could be as low as 15 degrees for many areas
in Central AL. While this noticeably cold wind will require some
extra layers of clothes Friday morning, the forecast wind chills
do not quite get low enough to meet the criteria for any wind
chill advisory statements. (advisory criteria: 0 to -9 degrees)


Friday through Wednesday.

A 1040/42 MB high pressure ridge over the Central U.S. Friday
morning is expected to build further east and should be spread
across the eastern half of Conus by early Saturday although should
weaken a tad to around 1036/39 MB as it does so, but will still be
decent. We are expecting clear skies and lighter/near calm winds
with the ridge closer to Alabama for Friday night into early
Saturday. Thus, we will be primed and ready for the coldest air
temperatures of the season even though tonight may feel a degree
or two colder due to the wind/wind chill.

During the day Saturday, the ridge is expected to continue to
progress to the southeast and to the Atlantic Seaboard Saturday
night into early Sunday. So, while Saturday`s highs and Sunday
morning temperatures will still be very chilly, they should run a
few degrees higher than the previous day as we lose our cold air
advection with our low level flow turning back around due to the
exiting ridge. Moisture return should be enough by late Sunday for
a few showers to be possible across the northwest counties ahead
of another approaching frontal system. Sunday night into Monday
day will be our best rain chances of the upcoming week with this
second front. Rain chances will remain for Tuesday into early
Wednesday as a yet another front moves across, but moisture will
be limited with the third system with so little time between
fronts and thus rain chances/amounts should be low. For now, I am
not mentioning any form of wintry mix as moisture for early
Wednesday across the northern counties as the moisture should be
exiting behind the third system across the north before the colder
temperatures arrive.



18Z TAF Discussion.

Mid and high level clouds will continue across terminals through the
day behind a strong cold front. Northerly winds at 10-15 mph behind
the front will persist through the forecast period, although slight
weakening is expected after sunset. Gusts up to 20-22kts are
possible through 09/00Z.




A cold front will push through Central Alabama today. The air
mass will be too dry for any appreciable rainfall with the frontal
passage. Much colder air will move into the area today 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.


Gadsden     45  21  41  20  46 /  10  10   0   0   0
Anniston    46  24  42  22  47 /  10  10   0   0   0
Birmingham  44  25  41  23  48 /  10  10   0   0   0
Tuscaloosa  47  24  43  22  49 /  10  10   0   0   0
Calera      46  25  43  23  49 /  10  10   0   0   0
Auburn      49  28  45  26  48 /  10   0   0   0   0
Montgomery  51  28  47  24  52 /  10   0   0   0   0
Troy        51  26  46  23  51 /  10   0   0   0   0




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