Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 061938

Area Forecast Discussion
National Weather Service Birmingham AL
238 PM CDT Wed Jul 6 2022

/Updated at 106 PM CDT Wed Jul 06 2022/

Through Thursday.

Upper and mid-level ridging will remain over the Tennessee Valley
region today while surface high pressure stays to our south
across the Northern Gulf of Mexico. The mid and upper level
ridging will gradually migrate westward, becoming centered over
Arkansas late tonight into Thursday. Surface high pressure will
remain to our southeast while a cold front stalls to our north
across the Southern Ohio River Valley region on Thursday. Some
weak disturbances will rotate over portions of the Southern Ohio
River Valley on Thursday.

High temperatures in the low to mid 90s along with dew points in
the low to mid 70s will result in heat index values reaching 105
across much of the area today with some increase in the values
expected on Thursday. A heat advisory will remain in effect today
and through Thursday at least across the entire forecast area.

The wet microburst risk is on the upper end of the low range
again today. Strong low-level instability will support vigorous
updrafts, however, warm temperatures aloft continue to result in
poor lapse rates which is limiting the extent of convective
development. Drier air continues to persist aloft, generally above
600 mb and may result in gusty winds from the heavier storms if
they manage to develop.


Expect partly cloudy skies today with isolated showers and some
thunderstorms. The activity this morning again was along some of
the higher terrain across the east and northeastern counties. The
south and southwest counties experienced lingering low stratus and
patchy fog, which has led to heating in these areas being delayed
until the clouds mixed out late this morning. PoPs will be
highest across the eastern portion of the area. Winds will be
southwest at 4-8 mph. Highs will range from the lower 90s in the
higher elevations east to the mid 90s elsewhere.


Showers with a few storms will linger into late evening followed
by persistent scattered clouds. Some patchy fog may briefly
develop towards daybreak on Thursday morning. Winds will be near
calm with lows in the mid 70s areawide.


Clouds will again be on the increase through the morning hours,
especially across the northeastern half of the area as potential
will be increasing across the northeast for showers with some
storms to develop from mid to late morning. This activity looks to
continue to build through midday as it tries to work south and
west with time into the afternoon hours. Winds will be from the
west to southwest at 4-8 mph. Highs will range from the low 90s in
the higher elevations east to the upper 90s far south and far


/Updated at 0200 PM CDT Wed Jul 06 2022/

Made some adjustments in the extended for this weekend, regarding
rain chances. Upper level ridging will pull back to the west and
troughing develops east of the Mississippi River. A shortwave and
surface front will push southward, bringing more organized rain
chances this weekend. Alot will depend on the timing of the
shortwave and weak front, and expect some changes to this over
the next couple of days. Currently the best chance of rain for the
northern half of the area is Saturday afternoon and evening, with
that focus shifting southward on Sunday.


Previous long-term discussion:
/Updated at 404 AM CDT Wed Jul 06 2022/
Thursday night through Monday.

595 decameter ridge will remain parked overhead Thursday night and
Friday. Isolated showers and storms may linger into the early
evening hours Thursday before dissipating. Will keep an eye on any
stronger storms developing over Tennessee Thursday
afternoon/evening, but current thinking is they would dissipate
prior to reaching the forecast area due to the ridge. Shower and
storm chances Friday will range from isolated in the southwest
counties near the center of the ridge to scattered in the eastern
counties closer to weak waves in the northwest flow aloft. West
winds, presence of the ridge, and overall limited convective
coverage will send highs into the mid to upper 90s areawide, with
widespread advisory criteria heat indices in the 105F to 109F range.
A few spots could approach excessive heat warning criteria (110F)
which will be monitored. Will again have to keep an eye on any
stronger/possibly severe storms over Tennesse that could drop down
Friday night. These chances are somewhat better than Thursday night,
but mesoscale details remain unclear at this time.

The core of the ridge will become established over the Southern
Rockies by Saturday, while a trough amplifies along the East Coast
south of an upper low over the Gulf of St. Lawrence. This puts
Central Alabama under somewhat enhanced northwest flow aloft. A weak
shortwave and a front approaching from the north along with 2.2 inch
PWATs will result in increased chances of showers and storms. This
may include semi-organized multicell clusters and/or an MCS, but
confidence in the details/possible severe threat is low at this
time. Limiting factors for severe storms would be warm temperatures
aloft (500mb temps of -4 to -5C) and saturated profiles (lack of dry
air aloft), but will continue to monitor. The temperature/heat index
forecast will be dependent on the placement of any outflow
boundaries from Friday night`s convection, as well as the timing of
new initiation, but anywhere that is outflow/convection free by
midday will see heat indices in the 105F to 110F range.

The front will be unable to cause much of an air mass change at the
surface, but northerly flow aloft will bring in some lower PWATs
across the northwest half of the area Sunday, while high rain
chances continue in the southeast half of the area. A few spots in
the southern and western counties could still see heat indices
around 105F on Sunday. The drier air brings a decrease in rain
chances for Monday and Tuesday. The ridge begins to nose back in
from the west, sending highs back into the low to mid 90s again.
Forecast heat indices remain below 105F on Monday but begin to
approach 105F again on Tuesday.



18Z TAF Discussion.

VFR conditions will prevail outside of showers and a few storms
this afternoon through the evening hours. Included TEMPO groups
for the eastern and northern sites for most likely window for
showers. There will be a few thunderstorms, but potential is too
low to include for any location. Scattered clouds will continue
across much of the area overnight with bases decreasing into at
least MVFR category after midnight. Some patchy fog may develop
before sunrise Thursday morning with best potential south. Cumulus
will develop again by mid to late morning with shower activity
expected to develop across the east/northeast with chances
expanding south and west with time past the end of this forecast




The hot and humid air mass will remain in place through the week,
with scattered showers and storms each afternoon. Minimum RH
values remain in the 45 to 55 percent range each afternoon. 20 ft
winds remain light, less than 10 mph.


Gadsden     73  93  73  97  73 /  40  50  20  40  40
Anniston    74  94  75  96  74 /  40  50  20  40  40
Birmingham  77  96  76  97  76 /  40  50  20  30  40
Tuscaloosa  76  98  77  98  77 /  30  30  20  20  30
Calera      75  96  76  95  77 /  40  50  20  30  30
Auburn      74  93  76  94  76 /  40  50  20  40  20
Montgomery  76  96  77  98  77 /  40  40  20  30  20
Troy        75  96  75  96  75 /  40  40  20  40  10


Heat Advisory until 9 PM CDT Thursday for the following
counties: Autauga...Barbour...Bibb...Blount...Bullock...
Shelby...St. Clair...Sumter...Talladega...Tallapoosa...


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