485
FXUS64 KHUN 030752
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
252 AM CDT Wed Jul 3 2024

...New NEAR TERM, SHORT TERM, LONG TERM...

.NEAR TERM...
(Today)
Issued at 251 AM CDT Wed Jul 3 2024

Tranquil weather across the Tennessee Valley early this morning
with only a few clouds present across the area. High pressure
centered over the Southern Appalachians will remain the dominant
weather feature across the region again today. Strong subsidence
from the ridge will suppress any potential for afternoon
convection (save for a rogue storm or two), with NBM dropping PoPs
below 15% areawide this afternoon. The main story will be the
dangerous heat and humidity later today. Ample sunshine will once
again warm temperatures into the mid to upper 90s, but dewpoints
climbing into the mid to prehaps upper 70s will help to create
heat index values in the 105-109 range across much of the region
later today. Subsequently, a Heat Advisory will be in effect
starting at 18z across the entire region.

&&

.SHORT TERM...
(Tonight through Friday Night)
Issued at 251 AM CDT Wed Jul 3 2024

We`ll get almost no relief from the heat overnight, with
temperatures only dropping into the 75-80 degree range. The ridge
begins to flatten, but remain centered across the Deep South on
Thursday (4th of July). This weakeness in the ridge and the deep
Gulf moisture in place will allow for a better potential for
afternoon showers/storms (30-50%). Most locations will remain dry,
however, even with these pulse storms briefly developing during
the afternoon/early evening window. The main story for the 4th of
July will be the heat, with mid/upper 90s highs and mid/upper 70s
dewpoints creating heat index values between 105-110 degrees
over much of the area. Heat index values over 110 are possible
across portions of northern Alabama, especially the HSV/DCU/MSL
metros. It`s possible an Excessive Heat Warning may be needed on
Thursday if these higher heat indicies are realized. The Heat
Advisory continues tonight and will last through Thursday/Thursday
night and the day on Friday.

The center of the high pressure ridge that will bring us the
dangerous heat over the next 2-3 days will become squeezed to the
SE of the area over the GA/SC/NC coast. Meanwhile, a fairly
robust mid/upper trough will swing from the northern Plains into
the Great Lakes, with its associated cold front pushing from the
mid- Mississippi and lower Ohio Valleys into the Tennessee Valley
and Deep South region on Friday. Ahead of the front, appreciable
destablization of the boundary layer will take place as
temperatures again warm into the mid 90s (with heat index values
between 105-109 again). This instability combined with the forcing
from the cold front will create an environment favorable for
showers and thunderstorms (70-90%), including a few strong storms.
Gusty winds and heavy downpours will be the main threats with the
strongest activity.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 251 AM CDT Wed Jul 3 2024

Upper level high pressure will persist over the northern Gulf coast
through much of the long term period. Meanwhile, an upper trough over
the central CONUS will very slowly begin to shift to the east and
northeast over the Midwest, Ohio Valley, and Great Lakes regions
early next week. This pattern leaves the Tennessee Valley in a sort
of weakness into early next week, with southwesterly flow aloft. At
the surface, a cold front looks to enter the Tennessee Valley
Saturday morning and meander over the region through early next week.
High pressure looks to build in to the north, with high pressure
over the northeastern Gulf of Mexico. With these upper level and
surface patterns, expect daily chances of showers/storms from
Saturday through Tuesday, especially during the peak heating hours of
the afternoon. Generally, chances are low to medium (20-50%) each
day with the exception of Sunday where chances are low (15-30%).

We`ll be keeping an eye on trends for Monday and Tuesday because
model guidance suggests that shear will increase to between 20-30
knots. While model instability values are under 1000 J/kg at this
point, it`s sufficient for the development of thunderstorms. Overall,
what this means is that there is potential for a few stronger storms
Monday and Tuesday. Confidence in anything severe is low, but heavy
downpours, lightning, and gusty winds are all possible.

As for temperatures, the daily chances of showers and storms may
quell the heat a bit this weekend through early next week. Highs on
Saturday are forecast to only reach the upper 80s to around 90
degrees, whereas Sunday and Monday it`ll be a bit warmer (low 90s).
Then, on Tuesday, highs looks to be similar to Saturday. This will
result in heat indices generally in the 90s this coming weekend, then
mid 90s to around 101-102 degrees in spots Monday and Tuesday. While
these values as a whole are a fair bit below Heat Advisory criteria
(105-109 degree heat indices), please remember heat safety if you
have outdoor plans. Take breaks in the shade and drink plenty of
water!

&&

.AVIATION...
(06Z TAFS)
Issued at 1240 AM CDT Wed Jul 3 2024

VFR conditions will prevail at each terminal through the period
with southerly winds and FEW/SCT decks of Cu developing later in
the day.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory from 1 PM this afternoon to 7 PM CDT Friday for
     ALZ001>010-016.

TN...Heat Advisory from 1 PM this afternoon to 7 PM CDT Friday for
     TNZ076-096-097.

&&

$$

NEAR TERM...AMP.24
SHORT TERM....AMP.24
LONG TERM....26
AVIATION...AMP