Heat Advisory 2, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
1226 PM CDT Wed Jul 15 2020

.UPDATE...
For 18Z Aviation.

&&

.SHORT TERM...
/Updated at 1133 AM CDT Wed Jul 15 2020/

Features.

Sprawling upper-layer ridging remains in place across much of the
Southern United States with the center of the mid-layer ridge
remaining to our west, now centered over Central Texas. Lower-
level ridging was analyzed from the Southwest Atlantic Basin west
across Florida and into the Central Gulf of Mexico.

13z hand surface analysis depicted higher pressures across the
northern half of the state with lower pressures generally along
and south of the U.S. Highway 80 corridor. A diffuse surface
boundary remains positioned across this area.

The 15.12Z BMX sounding contains ample dry air aloft above 750
mb. While the deeper layer dry air aloft across our northern
counties will help to limit convective development, moisture
content through the vertical column will be greater further to the
south. Our southern counties will also be more favorable for
convective development being closer to the weak surface boundary
along with the lingering weak upper-level disturbance over the
Northern Gulf of Mexico. As a result, the wet microburst risk will
be moderate generally across the southern third of the forecast
area with a low risk elsewhere. Expect the potential for a few
strong to severe storms posing a risk for damaging winds this
afternoon and evening.

Forecast.

Today.

Expect partly cloudy skies with isolated showers and
thunderstorms north while our southern counties will experience
scattered showers and storms. Some storms south may be strong to
severe with a risk for damaging winds due to wet microbursts.
Highs outside of convection will range from the low 90s east to
the mid 90s south and west. Peak heat indices will be around 105
degrees across our far southwest counties, but the extent and
duration precludes the issuance of a heat advisory at this time.

Tonight.

Expect showers and a few storms to linger after dark across
portions of our southern and eastern counties with isolated PoPs
in these areas. Otherwise, skies will be fair with lows ranging
from the low 70s northeast to the mid 70s west.

Thursday.

Partly cloudy skies are again forecast during the day Thursday
with isolated to scattered showers and thunderstorms across much
of the area with the lowest chances to the northwest. Highs will
range from the low 90s east to the mid 90s west. Heat indices will
be highest across portions of our far southwest and far west-
central counties but the limited duration precludes the issuance
of a heat advisory at this time.

05

.LONG TERM...
/Updated at 0327 AM CDT Wed Jul 15 2020/

Friday through Tuesday.

An expansive upper-level ridge is forecast to be centered near the
I-40 corridor through the long term period. On Friday and Saturday,
a surface to 700 mb ridge axis over North Georgia may help maintain
a westward moving area of below average PWAT values across Alabama,
resulting in only isolated daytime convection. Some weakening of
the ridge and a general moistening trend could begin on Sunday and
continue through Tuesday. Rain chances are currently expected to
increase from 20 percent on Saturday, to 30 percent on Sunday and
to 40 percent on Monday and Tuesday.

87/Grantham

&&

.AVIATION...
18Z TAF Discussion.

Scattered cloud bases expected to remain in VFR height range
outside of convection this afternoon and evening. Best chances for
RA and TS will be at our southern terminals.

Have included TSRA tempo groups starting at 19z at TOI and 20z at
MGM for northward propagating outflows from coastal convection
this morning. Expect scattered showers and storms to persist
across the south this afternoon into the evening followed by
potential for lingering showers southeast. Chances for SHRA and a
few TS will exist elsewhere this afternoon and evening but chances
decrease the further north you get. Probabilities are too low to
include at any of our northern sites.

Expect VFR conditions overnight except in locations that receive
convection today as they may experience some brief reduction in
VIS early Thursday morning. Lingering showers will be possible
southeast.

Thursday will feature scattered cumulus developing by mid to late
morning with scattered showers and thunderstorms. While chances
will be greater in extent, confidence remains too low to include
at any northern location through the end of this cycle.

05

&&

.FIRE WEATHER...

Showers and storms may become numerous across the southern areas
today with less activity to the north. Winds should be light and
variable. Rain chances begin a downward trend on Thursday, and
that continues through Saturday. Hot and humid conditions will
continue.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     72  93  72  93  72 /  10  40   0  20   0
Anniston    72  91  72  93  72 /  10  40   0  20   0
Birmingham  74  95  75  94  74 /  10  40   0  20   0
Tuscaloosa  74  94  75  95  74 /  10  40   0  20   0
Calera      72  92  73  94  73 /  20  40   0  20   0
Auburn      73  91  72  92  72 /  30  40  10  20   0
Montgomery  73  93  75  95  74 /  30  40  10  20   0
Troy        71  92  73  94  73 /  30  40  10  20   0

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
833 AM CDT Wed Jul 15 2020

ALZ011>015-017>050-161645-
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee-
Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega-
Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa-
Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon-
Bullock-Lee-Russell-Pike-Barbour-
833 AM CDT Wed Jul 15 2020

This Hazardous Weather Outlook is for the counties served by the
National Weather Service office in Birmingham.

.DAY ONE...Outlook through Tonight.

A few strong to severe thunderstorms may occur this afternoon and
evening with the primary risk being damaging winds in excess of 60
mph.

Heat indices may briefly reach 105 degrees this afternoon for areas
along and south of a line from Fayette to Clanton to Auburn.
Confidence remains low at this time, so stay tuned for updates.
Take extra precaution if spending time outdoors.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Heat indices may reach or exceed 105 degrees during the afternoon
Thursday through Friday. Take extra precaution if spending time
outdoors.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management will needed
this afternoon and evening. Please follow all local, state, and CDC
guidelines in regards to travel.