Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 270443

Area Forecast Discussion
National Weather Service Birmingham AL
1143 PM CDT Wed Jul 26 2017

For 06Z Aviation.


Through Friday.

Scattered showers and storms developed around mid day around the
Birmingham metro area, with activity now developing along the cold
pool/outflow boundary left from the initial activity. General
storm motion is to the south. Activity will remain isolated to
widely scattered through the remainder of the afternoon and early
evening. Overnight, fog is possible given high low level moisture
and wet ground conditions at locations that saw rainfall today.
It will continue to feel muggy tonight, with lows in the low to
mid 70s.

The most significant impacts from today so far occurred along
Highway 31 and Patton Creek in Hoover and Vestavia, where flooding
of businesses and homes occurred. Looking at radar estimated
rainfall amounts and local observations, 3 to 3.5 inches of heavy
rain fell in roughly an hour.

Looking toward the end of the week, the focus for showers and
storms tomorrow should shift to east Central Alabama as the upper
level ridge noses into the area from the west. On Friday, a front
will approach from the north with scattered to numerous showers
and storms possible areawide. Creeks continue to run high, and
ground conditions are saturated or near saturated in most areas
across north Central Alabama, given above normal rainfall
occurring now for much of the summer. Heavy rainfall will be
possible with any development tomorrow or Friday. If activity
moves over areas that have seen rainfall the last several days,
especially the more flashy locations, localized flooding could be
a possibility. We will be adding localized flash flooding to the
HWO for Friday and Friday night.

The previous discussion below covers more forecast details through
the end of the week.


Thursday through Wednesday.

Another hot/humid day in store for Thursday. Upper level ridging
slides slightly eastward as the low level high pressure sets up over
the Texas coast. A broad/weak low is still present over Southern GA
as we get into the afternoon, so could see some afternoon
showers/storms in the eastern half of Central AL. For the western
half, westerly flow brings in some drier air in the lower levels.
With the light winds aloft, expect that this drier air could mix
down in the afternoon, lowering the dewpoints. With 1000-850mb
thickness approaching 1440m, still expect afternoon highs to be in
the mid to upper 90s in the western counties and the low 90s for the
eastern counties. Heat indices are forecast to approach and
possibly hit 105 in some areas in the western portions of Central
AL, so will continue mentioning heat impacts in the HWO. The
question will be just how much afternoon mixing can occur to
decrease the surface moisture, limiting the heat index.

A surface low moves through the Ohio River Valley on Friday and
stretches a cold front down through the TN Valley. An upper level
trough helps push this cold front south through Central AL Friday
night into Saturday morning. The PWATs ahead of this system are near
or just above 2.5", so expect heavy rainfall with the storms that
form along the frontal boundary. Latest model runs have sped this
frontal passage up some, pushing it south of our area by Saturday
morning. Have kept some lower-end chance PoPs in the forecast for
our southeastern areas even after this front passes due to the
trough axis hanging around. Otherwise, drier and cooler weather
filters in with the northerly flow for the weekend and into early
next week.



06Z TAF Discussion.

Most of convection was done for the night. However, within the
last couple of hours we have had some small widely scattered
SHRA/TSRA drift SW into C AL from GA. There is a small chance
activity could hold together or develop over MGM/TOI. Will be
keeping an eye for possible necessary amendments. Some MVFR,
possibly lower fog will be possible tonight as we are SKC across
much of the area (except for some 5-7 KFT clouds SE of I85
corridor) as our dew point depressions lower. Confidence is too
low to add cigs. Although we had plenty of rain across C AL
today, not as much fell at the terminals. This may bode well
against dense fog/low cigs late tonight.




Isolated to scattered rain chances today and tomorrow and ridging
builds in. Light winds at the surface and aloft will limit
dispersion for the next couple of days. Hot and humid weather, so
no fire weather concerns at this time.


Gadsden     73  92  73  89  71 /  20  20  20  60  40
Anniston    73  92  73  90  72 /  20  30  10  40  50
Birmingham  76  94  76  91  74 /  20  20  10  50  50
Tuscaloosa  75  96  75  92  74 /  20  20  10  50  50
Calera      74  93  75  92  74 /  20  20  10  40  50
Auburn      73  90  74  91  73 /  20  30  10  30  40
Montgomery  75  94  76  94  75 /  20  30  10  30  40
Troy        72  93  73  93  73 /  20  30  10  30  40




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