531
FXUS64 KHUN 200204
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
904 PM CDT Fri Jul 19 2024

...New NEAR TERM...

.NEAR TERM...
(Tonight)
Issued at 904 PM CDT Fri Jul 19 2024

A convergence axis at near 850-mb was a primary forcing
mechanism for convection across north Alabama this afternoon and
evening. Heavy rainfall rates from high PWATs was aided by slow
storm motions and redevelopment on the southwestern flank, leading
to daily rainfall totals near 2-3" for portions of the TN Valley.
Loss of daytime heating has led to a decrease in convective
activity this evening. Farther south, a stationary boundary draped
over Central AL continues to produce areas of thunderstorms.
Remnant outflow boundaries from this activity are likely to push
northward and bring additional showers and storms to portions of
northeast AL overnight (50-60% chance).

Throughout the overnight period, debris cirrus will stream
northward from the Central AL/GA convection. Between the areas of
cirrus, any areas of clearing that experienced rain today have a
chance to develop fog (40-60%). An alternate scenario to monitor
is that low stratus develops rather than fog. However, because fog
development occurred last night, tonight`s forecast will lean
more on persistence. Otherwise, temperatures will drop into the
upper 60s to low 70s.

&&

.SHORT TERM...
(Saturday through Monday)
Issued at 155 PM CDT Fri Jul 19 2024

Southerly flow around the Bermuda high will provide ample moisture
to support afternoon rain and storm chances each afternoon across
the TN Valley. HIRES model soundings indicate 1000-2000 J/KG of
CAPE each afternoon will maintain the potential for a stronger
storm within mostly general summer thunderstorms. The biggest
threat will be heavy rainfall due to the moist low levels and slow
steering flow. For those partaking in outdoor activities frequent
lightning and gusty winds will be an additional concern.

High temps will be limited to the mid to high 80s each day thanks
to the mostly overcast skies. Overnight conditions will be
incredibly saturated supporting fog development each night.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 244 AM CDT Fri Jul 19 2024

A wetter and cooler change from the generally dry and hot summer is
expected for much of the new workweek. A frontal boundary which is
currently south of the area, will translate northward over the
weekend. It should move north of the area on Sunday, and remain into
the new week. The boundary`s northward movement will in part be
induced by troughing amplifying southward from the Great Lakes, with
the upper highs displaced to over the Desert SW and NW Atlantic
Basin. With the surface front to our north, a lower level southerly
flow will bring deep moisture from the Gulf of Mexico more inland.
This should produce precipitable water amounts into the 2" or higher
range over and near the Tennessee Valley for this period.

Thus we will have better opportunities for more of the area to
receive much needed rainfall. With the higher moisture values and no
real focusing mechanism, have stayed with a diurnal trend regarding
rain chances, with the best chances in the afternoon hours. Given
that the precipitation will be as showers, have trimmed down from
categorical (75-100%) chances to likely (55-74%), as not all areas
will experience rainfall. Even so, higher rain chances should help
temper some of the drought. Rainfall totals of 1.75" to nearly 3.00"
could fall in the Mon-Thu timeframe. Until more heavy rainfall
impacts the area, am not pushing a flood threat at this time. That
said, areas that experience locally heavy rains could experience
ponding of water, with flash flooding a non-zero chance.

With more clouds than sun and good rain chances, recent summer hot
temperatures will apparently be taking a break next week, with highs
in the 80s. In this issuance, we have highs in the mid/upper 80s
Mon/Tue, and in the low/mid 80s Wed/Thu.

&&

.AVIATION...
(00Z TAFS)
Issued at 628 PM CDT Fri Jul 19 2024

Several showers and a few thunderstorms are continuing to impact
areas south of both terminals this evening and coverage should
decrease in the next 2-3 hours. AWWs are not expected. Overnight
fog and low stratus becomes a concern in the early morning hours
with a low chance of IFR ceilings. Any fog and low stratus will
mix out and lift in the morning before showers and storms return
again in the afternoon.

&&

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

$$

NEAR TERM...30
SHORT TERM....RAD
LONG TERM....RSB
AVIATION...30