Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 110532

Area Forecast Discussion
National Weather Service Birmingham AL
1132 PM CST Mon Dec 10 2018

For 06Z Aviation.


Through Tonight.

An upper level trough axis is pushing southward through the area
today, and is responsible for the light rain/snow flurries
occurring across portions of north Central Alabama. As this trough
shifts southward, so will the chance for light rain/snow flurries
this evening. Forecast soundings show a warm layer at the surface
and then profiles hover around 0C for about the lowest 2kft. This
is likely too warm for any snow showers, but cannot rule out some
flurries mixing in with light rain. The best chance of seeing a
few flurries is near and north of a Tuscaloosa to Calera to
Wedowee line. Further south, airmass above the surface is slightly
warmer and will carry only a mention of light rain.

Ground temperatures and surface air temperatures are above
freezing right now, and travel impacts due to any wintry
precipitation is not expected this evening. Overnight, after
precipitation ends, temperatures will fall below freezing.
Overnight lows will be in the mid 20s north to mid 30s southeast.

With not knowing specific conditions of all area roadways, it is
possible for some slick spots early Tuesday morning across the
north, given expected temperatures well below freezing. Be
cautious during your morning commute, especially on roads where
standing water remains or on roads that are prone to poor


Tuesday through Saturday.

The main trough axis has pushed east of our area by early Tuesday
morning, with ridging building in across the Southeastern States.
Tuesday will be mostly clear and dry with milder temperatures as the
surface high slides eastward across Central AL.

The upper level pattern remains fairly active through at least the
end of the week. An upper level shortwave moves through the Ohio
River Valley on Wednesday, but this should remain to our north and
the departing surface high will still keep most of the energy and
lift out of our area. At the least, we`ll likely see an increase in
cloud cover, keeping our afternoon high temps in the low to mid 50s.

Late Wednesday night into Thursday, a deepening trough digs through
the Rockies and develops a surface low in the Southern Plains. As
this trough digs, shortwave energy gets ejected through the base and
will push eastward into the MS River Valley by early Thursday
morning, increasing rain chances in the western portions of Central
AL. The surface low continues to deepen as it slowly moves through
the ArkLaTex Thursday night into Friday. As it moves into MS,
widespread rain will push across Central AL Thursday night into
Friday. At this time, instability looks to be limited to the coastal
areas, so I will not include mention of thunder in the forecast.
However, guidance suggests a tight pressure gradient across the
region with the approaching surface low, so I do expect this
Thursday evening to Friday time to have gusty winds with the rain.
I`ve nudged winds up in the forecast but stopped short of "wind
advisory" criteria because neither NAEFS nor ENS guidance really
show this low to be highly anomalous, leading to lower confidence in
widespread high winds. Therefore, I will not mention wind in the
HWO, but will continue to monitor model trends in the next few days.

The upper level low remains over the Gulf States through Saturday
morning, leading to at least some rain chances lingering behind.
I`ve started decreasing PoPs from the southwest to the northeast
Saturday afternoon. By Saturday evening, the upper level low should
on its way out, ending rain chances across Central AL.


Sunday and Monday.

The upper level low has pushed east of the area with brief ridging
building in from the west. Another low will develop in the
southwest CONUS and progress eastward bringing another chance of
rain next week. Have begun to trend towards increasing PoPs Sunday
evening, however, due to inconsistencies in timing of development
and progression of this next system, which leads to uncertainty in
moisture return, I have not added any mentionable PoPs at this



06Z TAF Discussion.

Lower clouds continue to push south and east of our area overnight
tonight. Many of our northern sites have already seen rising CIGs
to VFR. This trend will continue over the next several hours with
MGM and TOI likely being the latest in becoming VFR around 12z.
Some patchy fog can`t be ruled out as GOES-16 imagery does show
some isolated pockets to our north and west where the lower clouds
have cleared out. However, confidence in the fog impacting any
specific terminal is too low to mention in the TAFs right now. VFR
conditions will persist through 06z with generally light northerly
winds in the afternoon.




Isolated to scattered light rain showers and snow flurries will
continue this evening, ending overnight. Low clouds will persist
this evening and across the south Tuesday morning. Will need to
watch for patchy fog as well, as skies clear before sunrise.
Drier conditions expected Tuesday and Wednesday, ahead of the next
rain system on Thursday. There are no fire weather concerns at
this time.


Gadsden     26  46  28  51  41 /  10   0   0   0  20
Anniston    26  49  29  53  42 /  20   0   0   0  20
Birmingham  27  49  31  54  44 /  10   0   0   0  20
Tuscaloosa  28  51  31  55  46 /  10   0   0   0  20
Calera      27  50  31  54  44 /  30   0   0   0  20
Auburn      31  51  32  54  42 /  20   0   0   0  10
Montgomery  31  52  31  57  45 /  20   0   0   0  10
Troy        33  52  31  58  45 /  20   0   0   0  10




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