966
FXUS64 KHUN 012341
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
641 PM CDT Mon Jul 1 2024

...New AVIATION...

.NEAR TERM...
(Remainder of today and tonight)
Issued at 224 PM CDT Mon Jul 1 2024

Light NNW flow aloft will persist across the TN Valley for the
remainder of the day, to the east of a strong subtropical ridge
centered across northeastern TX. At the surface, gusty NNE winds
will continue to advect a drier boundary layer airmass into the
region through sunset, due to a contracted pressure gradient
between a high over the Great Lakes and a developing frontal wave
across southern GA/northern FL. Highs appear on track to reach the
u80s-l90s.

Current thinking is that dewpoints will continue to slowly fall
into the mid 50s this evening, which should allow for several
hours of accelerated cooling (and potential development of patchy
fog near large bodies of water) as northeasterly winds subside and
skies remain mostly clear. Shortly after Midnight, surface winds
will begin to veer to SE as the frontal wave to our south
retrogrades along the central Gulf Coast and the ridge to our
northeast expands southwestward in the lee of the Appalachians.
This will quickly begin to advect low- level moisture (and some
stratus clouds) northwestward into the region, with lows ranging
from the mid 60s (NW) to u60s-l70s (SE).

&&

.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 224 PM CDT Mon Jul 1 2024

Latest model consensus suggests that the center of the strong
subtropical ridge (noted above) will build slowly eastward
Tuesday/Tuesday night, becoming centered across the Gulf Coast
states of MS-AL-GA on Wednesday/Wednesday night. In the lower
levels, SSE flow will gradually strengthen Tuesday and Tuesday
night as the center of the surface ridge (noted above) translates
eastward and offshore the northern Mid-Atlantic coast. Dewpoints
will climb back into the 65-70F range for most of the CWFA
(perhaps a bit higher in the west and a bit lower in the east,
where impacts from the dry continental airmass will linger),
resulting in heat index readings in the 100-105F range from
Lincoln-Madison-Marshall counties westward as afternoon highs
return to the l-m 90s.

During the Wednesday-Wednesday night timeframe, a surface cold
front related to a northern stream mid-level trough lifting east-
northeastward into Ontario/Quebec will drift into the OH Valley
before stalling. This will occur as a low-level ridge axis becomes
established along the central Gulf Coast, resulting in lighter
SSW winds across our region. Dewpoints will slowly increase into
the l-m 70s for the entire region in this regime, which (coupled
with a minor increase in highs on Wednesday) should achieve Heat
Advisory criteria for the same portion of the CWFA mentioned in
the paragraph above. Strong heating of the increasingly moist
boundary layer may also generate a few showers/thunderstorms on
Wednesday afternoon/evening, but due to the position of the
subtropical ridge across our region we have only included a low
(15-20%) chance POP in the grids.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 209 AM CDT Mon Jul 1 2024

An upper ridge will continue to maintain its hold over the
southeastern states to start the long term. However, a shortwave
trough moving over the north-central CONUS and Midwest will cause
the ridge to flatten over the Tennessee Valley on Friday. This
impulse will quickly progress to the northeast into Canada on
Saturday; but, the parent trough will persist over the central
portion of the country through the weekend as the aforementioned
ridge is pushed over the Deep South and off over the Atlantic. The
surface pattern will largely mirror the upper level pattern, as
surface high pressure over the Southeast is shunted south and
eastward as a cold front moves over the Mississippi Valley on
Friday. This front looks to slowly make its way towards the
Tennessee Valley by early Saturday, then stall over the region and
weaken by Sunday.

For sensible weather, expect daily chances of showers and storms
increasing through Friday where medium to high chances (50-70%)
are forecast. Medium chances (40-50%) continue on Saturday, then
decrease to low (20-30%) by Sunday as the surface front weakens
over the region. While models show ample instability through the
weekend, shear is fairly meager on Thursday and Friday. Therefore,
anticipating the usual summertime thunderstorms that may produce
brief, heavy downpours, lightning, and some gusty winds. Although,
some guidance indicates that shear values increase to between
20-25 knots or so on Saturday. This would suggest that some
stronger storms may be possible on Saturday. However, we will
continue to monitor these trends over the next few days.

The other concern for the long term period will be the heat,
particularly on Thursday (Independence Day holiday) and Friday.
High temperatures these days are forecast to reach the lower to
mid 90s. Dew points are also expected to be in the lower to mid
70s during the day, with lows Wednesday, Thursday, and Friday
nights in the lower to mid 70s. This will result a major risk of
heat for much of the local area both Thursday and Friday
(according the the NWS HeatRisk tool). Just strictly looking at
heat indices, we`re looking at generally between 100-109 degrees
both days as well. These will be the days to watch for any
potential heat products, but please remember heat safety this 4th
of July holiday! Take frequent breaks in the shade, wear loose-
fitting and light-colored clothing, and stay hydrated! A very
slightly cooler weekend will then follow as highs top out in the
lower 90s with lows Saturday night in the lower 70s.

&&

.AVIATION...
(00Z TAFS)
Issued at 641 PM CDT Mon Jul 1 2024

VFR conditions will continue through the TAF period at both
terminals as winds veer from the north to the southeast. Gradient
flow will increase tomorrow resulting in sustained winds near
10kts with gusts up to 15kts.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

$$

NEAR TERM...70
SHORT TERM....70
LONG TERM....26
AVIATION...25