Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 200007

Area Forecast Discussion
National Weather Service Birmingham AL
707 PM CDT Fri Jul 19 2019

For 00Z Aviation.


/Updated at 0324 PM CDT Fri Jul 19 2019/

An upper level wave will slowly move westward across the area
tonight, helping to keep at least isolated shower and storm
development overnight. With weak steering winds, storm motions
will be low and will need to continue monitoring for localized
flash flooding through the early evening hours. Cannot rule out a
strong wind gust with stronger storms, but lightning will be the
greater threat for any outdoor activities.


/Updated at 0357 AM CDT Fri Jul 19 2019/

Saturday through Friday.

An inverted trough at 500mb with associated mid-level PVA will be
positioned over Alabama on Saturday and Sunday. Despite upper-level
ridging overhead, this shortwave feature will induce sufficient
lift, indicated by a bullseye of negative omegas over Central AL. A
moist vertical profile characterized by PWATs of 1.8 to 2.0 inches
will be present such that a widespread coverage of showers and
thunderstorms are expected. Chance to likely PoPs are forecast
across central Alabama for Saturday as a result. Highs were also
lowered a few degrees on Saturday with the rain and cloud cover
expected to keep most locations in the upper 80s to near 90 degrees.
On Sunday, highest rain chances will be in the west and southwest,
but should see less coverage since the trough will also be shifting
to the west over Mississippi.

Guidance continues to advertise a change in the pattern as we head
into next week. Meridional flow will return across the CONUS
beginning Sunday night with a stout deep-layer ridge developing over
the west and a trough quickly amplifying over the east. Though the
low height center will develop over eastern Canada, the base of the
trough will extend to as far south as the Gulf Coast indicating a
highly amplified setup. A cold front will approach the southeast on
Monday increasing rain chances for Monday through Wednesday. Global
models have been consistent on a frontal passage through Central
Alabama by Wednesday night with the boundary stalling along the
coastline on Thursday. Though uncommon for this time of year,
believe this solution is plausible based on the highly amplified
nature of the system. Therefore, the forecast for next week will be
dependent on the front ultimately stalling south of the forecast
area on Thursday. It is important to note that if the boundary
stalls further north, this could drive different conditions across
the forecast area on Thursday and Friday. Nonetheless, rain and
thunderstorms will be focused along the boundary as it moves south
with Likely PoPs across the forecast area Monday through Tuesday.
Nearly unidirectional flow through the column with only marginal
instability during the afternoon hours should stave off any
severe threat, though gusty winds will be possible with any
thunderstorm activity along the front. By Wednesday, highest rain
chances will be in the southeast as drier air begins moving in
north of I-85. The system should bring below-average highs next
week with lower rain chances Thursday and Friday as the front
stalls across far southeastern Alabama. Some relief from the heat
will come in the form of highs in the 80s north to near 90 degrees
in the south through the remainder of the extended forecast.



00Z TAF Discussion.

Today`s convection continues to decrease in coverage. TOI will see
some lingering light rain for another hour or so, and the isolated
nature of any potential development overnight will preclude any
mention in the forecast. A high cloud deck will stick around
through the night. Even with the light/calm winds and moist
airmass in place, the cloud cover will prevent any widespread fog.
However, did include lower visibilities and some possible low cigs after
08Z for ANB, ASN and TOI as they received over 1" of rain today.

Look for southwesterly winds of 5-10 kts on Saturday. Numerous
showers and storms are expected area wide by afternoon, with
activity likely starting by mid-morning (just like today).




Scattered showers and storms will continue through early evening,
with isolated storms possible overnight. A potentially much
wetter pattern still looks likely through the weekend into early
next week. Though latest KBDI values are in the 300-600 range
across Central Alabama, a moist airmass will remain in place, with
RH values remaining above critical thresholds.


Gadsden     71  87  71  88  71 /  20  70  30  50  40
Anniston    72  88  72  89  73 /  20  70  30  50  40
Birmingham  74  89  73  89  74 /  20  70  30  50  40
Tuscaloosa  75  89  73  90  74 /  20  60  20  50  40
Calera      72  87  72  89  72 /  20  70  30  50  30
Auburn      72  88  72  89  73 /  20  60  30  40  30
Montgomery  74  89  73  92  74 /  30  70  30  40  30
Troy        72  89  72  90  73 /  40  70  30  40  30




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