898
FXUS64 KBMX 282335
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
635 PM CDT Fri Jun 28 2024

...New AVIATION...

.SHORT TERM...
(This evening through Saturday)
Issued at 1237 PM CDT FRI JUN 28 2024

High pressure aloft will build into the state from the west today
through Saturday. Low and mid level flow will remain from the
south and the southwest with plenty of moisture advecting into the
state. Diurnal convection will be expected each day, with
development of isolated showers beginning by midmorning and
thunderstorms expected through the afternoon. Instabilities will
be on average between 2000 and 2500 J/kg each day. Shear is fairly
weak, though a few pockets of 20 kts is possible each afternoon.
PW values will be max this time of year climatologically. With all
this said, could expected a few storms to be strong, though severe
storms should be limited. A few slow moving or training storms
could cause localized flooding due to the high rainfall rates
expected.

Temperatures today will be in the lower 90s with lows tonight in
the low to mid 70s. Fog development is possible in a few areas
through the early morning, though with the winds expected to be
light and cloud cover to continue overnight, fog may be more
patchy in nature. Saturday afternoon, a few areas may reach heat
indices around 105, especially in the northwest where shower and
thunderstorm development is expected to be more isolated until later
in the afternoon. Areas in the south may actually stay around 100
degrees or slightly lower due to increase in cloud cover and
activity. May need a heat advisory, but but will continue to
assess.

24

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 236 PM CDT FRI JUN 28 2024

Not much change in the long term forecast this afternoon,
unfortunately. Although rain chances remain elevated given the
presence of an upper level shortwave and front, low level moisture
is high as well. And that will push heat indices into the 104-109F
range for most of the area Sunday afternoon. After a reprieve on
Monday and Tuesday, upper level ridging will build back into the
area and moisture to increase. Heat indices will be back in the
104-107F range for the end of the week.

14

Previous long-term discussion:
(Saturday night through next Thursday)
Issued at 333 AM CDT FRI JUN 28 2024

Key messages:

- Dangerous heat remains in the forecast for Sunday, dependent
  upon daytime heating occurring before showers and storms
  develop/arrive Sunday afternoon and evening. Heat indices
  between 105 and 110 degrees are currently forecast, and a Heat
  Advisory will likely be needed. Highest rain chances will also
  exist Sunday afternoon through Sunday evening as a cold front
  approaches from the north.

- A multi-day heat wave is still anticipated through much of next
  week, starting Tuesday and lasting through at least the end of
  the week. Heat indices are forecast at or above 105 degrees in
  many locations next Wednesday through Friday.

The 500mb ridge over Texas will continue to strengthen to 598
decameters, but retrograde slightly to the west on Sunday. This
will place Central Alabama within almost northerly flow aloft. The
upper level shortwave trough moving through the Great Lakes states
appears to be a bit more potent on guidance this morning, which
will help to push the surface cold front well into the Deep South.
As the front approaches, we`ll see low level moisture pooling out
ahead of the front with high PWATs in combination with strong
surface heating. As a result, dangerous heat will remain in the
forecast with temperatures rising into the low to mid 90s between
11am and 2pm. Heat indices could rise between 105 and 110 degrees
as dewpoints stay in the low to mid 70s. A Heat Advisory will be
needed if current forecast trends hold up. With the surface front
approaching from the north and a weak 500mb vort max moving in
from the northwest, scattered to numerous showers and storms are
expected to develop Sunday afternoon through Sunday evening. We`ll
have to see how soon some of the convection is allowed to
develop, as it may temper high temps a bit. In addition, a more
organized convective cluster of storms may develop and dive
southward through the day.

We can certainly hope that coverage of showers and storms will be
fairly widespread on Sunday to help with the dry conditions, as
significant rain chances aren`t expected through much of next
week with heat building once again. Model consensus is in good
agreement with the cold front moving at least as far south as the
U.S. 80/I-85 corridors by Monday afternoon, and potentially
farther south than that. Drier air is expected to advect southward
both at the surface and aloft, giving us a temporary reprieve from
the worst heat indices. We still could hit Heat Advisory criteria
in our far southern counties with scattered showers and storms
developing south of the front.

The 500mb ridge will build in across the Southeast through
Thursday, keeping high temperatures in the mid to upper 90s each
day. Isolated to scattered showers and storms will be possible
during the peak heating of the day mainly in the east and
southeast on Tuesday. As southeasterly to southerly low level flow
picks back up on Wednesday, scattered convection is expected
areawide during the peak heating of the day through the end of the
week.

56/GDG

&&

.AVIATION...
(00Z TAFS)
Issued at 628 PM CDT FRI JUN 28 2024

Afternoon heating and hefty dewpoints lead to the formation of
scattered showers this afternoon, which continued into the early
evening hours. Interestingly, relatively warm mid-level
temperatures limited the amount of mid-level instability, which
helped keep the convection from growing into thunderstorms. This
activity is expected to decrease in coverage and intensity
through the evening.

Overnight, I went largely with a persistence-based ceiling and
visibility forecast. This put the lowest ceilings, and best chance
at IFR conditions, at EET and MGM. Any stratus and light fog that
does form overnight should lift and mix out by around 15Z on
Saturday. Rinse and repeat in the afternoon, with more scattered
convection in the heat of the afternoon.

/61/

&&

.FIRE WEATHER...

Rain chances increase for Saturday and Sunday, as minimum RH
values remain in the 50 to 60 percent range both afternoons.
Southwesterly 20ft winds Saturday become northwesterly Sunday,
but remaining light between 5 and 10mph overall. Drier conditions
and less humidity is expected Monday and Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     72  91  72  94 /  20  60  20  70
Anniston    74  91  74  93 /  20  60  20  70
Birmingham  75  92  75  95 /  20  60  20  70
Tuscaloosa  75  93  74  95 /  20  60  10  70
Calera      75  93  75  95 /  20  60  20  70
Auburn      74  90  74  91 /  40  60  20  70
Montgomery  75  92  74  93 /  40  60  20  70
Troy        73  91  72  92 /  30  60  20  70

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...24
LONG TERM....14
AVIATION.../61/