264
FXUS64 KHUN 040539
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1239 AM CDT Sat May 4 2024

...New AVIATION...

.NEAR TERM...
(Rest of tonight)
Issued at 943 PM CDT Fri May 3 2024

Showers and thunderstorms that impacted much of the Tennessee
Valley in the later afternoon and this evening, for the most
part have ended. However, a few areas of showers remained. The
last of showers that were over the Cullman/Marshall county area
were slowly weakening as they moved across DeKalb county. A weak
disturbance that moved northward across NW Alabama has in part
helped new convection form along the AL/TN border. Other light
showers over parts of the area were on a fading trend.

With less showers and new model output indicating little to no
additional showers, have trimmed down rain chances areawide.
With numerous boundaries lurking from previous activity, along
with a still conditionally unstable environment, development
cannot be totally ruled out. Another mild night is expected as low
temperatures cool into the low/mid 60s.

One worry is a potential for the development of fog in the late
night. Much of the area has received measurable rainfall in the
last day. If denser high clouds move east of the area, less clouds
and a light wind could allow fog to form. But with on-going rain
chances and and low/mid altitude moisture remaining, have not
bought the fog solution; but it is something not to totally rule
out.

&&

.SHORT TERM...
(Saturday through Monday)
Issued at 202 PM CDT Fri May 3 2024

Saturday, and the remainder of the short term, offers the same
forecast challenges. A weak syntopic pattern remains in place with
broad mid level ridging to our east allowing for subsequent
shortwaves to ripple through the area. The passage of a shortwave
tomorrow afternoon will again trigger our highest chances and
highest coverage of rain and storms. Once again, tricky pop up
convection remains a possibility starting in the late morning
ahead of the shortwave.

This pattern continues on Sunday into Monday as a mid level trough
in the Plains pushes at least two more shortwaves through the
area. This will maintain medium to high PoPs across the CWA with
highest coverage of rain and storms reserved for each afternoon.
While each day will pose a threat for frequent lightning and heavy
rainfall, no severe weather is anticipated through the duration
of the short term. As for anticipated rainfall, overall weekend
QPF amounts will likely vary greatly in spatial coverage. With
favorable environmental factors in place for efficient rainfall
production, showers could easily dump a quarter to a half inch in
a brief period of time for isolated areas. While this alone is not
enough to raise flooding concerns, periods of heavy rainfall
could continue to trigger ponding of water and nuisance flooding
for urban area.

When it`s not raining, the tropical airmass will make for a
very humid weekend. Highs remain in the low 80s with dewpoints in
the high 60s each day.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 433 AM CDT Fri May 3 2024

After warm frontal convection spreads northeastward and out of
the region late Monday morning, the TN Valley will be solidly
within a very warm/moist tropical airmass, with dewpoints expected
to rise into the m-u 60s as southwesterly low-level flow
strengthens. Although this will contribute to greater instability
(especially during the afternoon hours), a mid-level ridge will
shift across the region downstream from the central Rockies upper
low as it begins to spread northeastward into the northern Plains,
and this should yield a lower coverage of mainly afternoon
thunderstorms from Monday-Wednesday. Overnight lows will steadily
increase into the u60s-l70s through the middle of next week (due
to both elevated SW winds and moisture advection), with highs also
warming into the mid (to perhaps upper) 80s by Wednesday.

Although details are unclear at this time range, conditions will
become more favorable for convection at the end of the extended
period (Wednesday night/Thursday), perhaps in the form of MCS
activity that may initiate along a cold front to our northwest and
propagate southeastward into the local area. Should this scenario
materialize, conditions will be favorable for organized severe
thunderstorms across our region, with boundary layer dewpoints in
the u60s-l70s beneath a belt of mid-level WSW flow of 35-45 knots.

&&

.AVIATION...
(06Z TAFS)
Issued at 1239 AM CDT Sat May 4 2024

Scattered to numerous showers and thunderstorms continue across
the area, with a general motion to the NE around 15kt. Additional
development is possible over the next few hours, as well. Outside
of convection, VFR conditions are expected. Before daybreak Sat,
there is a risk of patchy fog forming in/near areas that recently
received heavy rainfall. Otherwise daytime heating and resultant
instability could allow more showers and storms to form Sat
afternoon. Given uncertainty on development and where the activity
will impact, have a VCTS for the latter portion of the TAF at
both terminals.

&&

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

&&

$$

NEAR TERM...RSB
SHORT TERM...RAD
LONG TERM...70/DD
AVIATION...RSB