Area Forecast Discussion
Issued by NWS Birmingham, AL
FXUS64 KBMX 251138
Area Forecast Discussion
National Weather Service Birmingham AL
638 AM CDT SAT JUN 25 2016
For 12Z Aviation.
Today and Tonight.
Central Alabama will be under the influence of a strong upper ridge
today and tonight with the axis of the ridge centered near the
Mississippi River. A mid level trof axis extends across southern
Georgia and into east Alabama on the east side of the upper ridge.
This zone of slightly colder air aloft will aid in the development
of diurnal convection. It is somewhat unclear where the zone of
higher pops will be today given that the axis of higher PW`s will be
along I-65 and the axis of colder 500mb temperatures will be across
northeast Alabama. There will also be the influence of a weak low
level convergence over east Alabama. A surface low will develop over
south Georgia with a trof axis extending back into east Alabama.
Overall expect small coverage of convection today and tonight, but
placed highest pops across the northeast and east, respectively.
Given that temperatures will stay in the 80s this evening, storms
should continue throughout the evening hours.
Temperatures today will likely be a few degrees warmer today than
yesterday based on low level thickness forecasts. Surface dewpoints
will be highest along and west of I-65. Dewpoint temperatures will
likely mix out more across east Alabama, which will be on the east
side of the low level ridge axis, and keep heat indices below the
105 degree criteria. A heat advisory will be issued for areas along
and west of I-65 and south of I-85 for this afternoon and evening.
Given the weak mid level lapse rates forecast for this afternoon and
CAPE values only peaking around 2000 j/kg, there does not appear to
be a significant microburst threat.
Sunday through Friday.
With less influence from the upper ridge, isolated to scattered
convection will be possible area wide on Sunday, with the best
chances east of Interstate 65. With very little change in
atmospheric conditions from Saturday, heat and microburst
potential will once again be the main concerns. With highs
forecast to reach into the mid/upper 90s and dew points remaining
in the low 70s, heat indices near 105 degrees in becoming more
possible across the southern counties, where the temps will be
higher. Will have to monitor very closely for a potential Heat
Advisory. The combination of high PW values (near 2.0 inches),
steep low level lapse rates (>9.0 C/km) and rather large
instabilities (MUCAPE of 2500-3500 J/kg) will make for at least a
moderate risk of wet microbursts. Therefore, a few strong to
severe storms could be possible during the afternoon on Sunday.
The upper ridge continues to retrograde to the west early next week
with general troughing developing across the eastern CONUS. A weak
shortwave crossing the Great Lakes region will push a cold front
southward toward the TN Valley on Monday. With plentiful moisture
and the enhanced lift ahead of the front, expect scattered
showers/storms area wide on Monday, with the best chances across the
north, closer to the front. It will be hot and humid once again with
temps in most locations rising into the low/mid 90s. Not sure how
much afternoon convection will impact highs and how high dew points
will remain during the day, but will go ahead and mention a low
confidence heat in the HWO for Monday, mainly in the southern
A secondary, and stronger shortwave, will push the front further
south into Central Alabama on Tuesday and into south AL by late
Wednesday. Will not go any higher than high chance pops for any
period with the best rain chances gradually shifting southward with
the front. Drier and slightly cooler air will filter in behind the
front on Wednesday, mainly across the northern portions of the
forecast area. With the front still somewhere across the southern
part of the state on Thursday, isolated to scattered convection will
be possible, with the best chances in the south. Temperatures
mid/late week will be closer to normal for late June/early July.
12Z TAF Discussion.
VFR conds will prevail thru the period. Isold convection will
develop after 18z, but not enough confidence in where it will
develop to include in TAFs. Light nw winds will develop by 15z
across north Alabama with a more westerly component across
southern Alabama. Some light fog possible after 10z but not
significant enough to place at end of TAF period.
Typical summer weather is expected for the next several
days, although hotter than normal conditions are expected
over the weekend. No weather-related fire weather concerns
are expected at this time.
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 97 73 94 73 92 / 30 30 30 30 50
Anniston 97 73 95 73 92 / 30 30 30 30 40
Birmingham 97 75 96 75 94 / 30 20 20 30 40
Tuscaloosa 98 75 97 74 96 / 10 10 20 30 40
Calera 96 74 96 75 95 / 20 20 30 30 40
Auburn 97 74 95 74 93 / 20 30 30 30 40
Montgomery 99 75 98 75 97 / 10 20 30 30 30
Troy 98 73 96 74 95 / 10 20 30 30 30
Heat Advisory from noon today to 9 PM CDT this evening For the
following counties: Autauga...Barbour...Bibb...Bullock...