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000
FXUS64 KHUN 140437
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1137 PM CDT Sat Apr 13 2024

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 856 PM CDT Sat Apr 13 2024

Tranquil weather continuing across the Tennessee Valley late this
evening, with high pressure promoting clear/dry conditions. A weak
shortwave over the Southern/Central Plains will pivot eastward
into the Mid-Mississippi Valley overnight. Scattered decks of
mid/high clouds from this feature may begin to push into the area
late tonight and especially into the early morning hours on Sunday.
SSW/SW flow between 5-10 mph overnight will also help to maintain
this much milder air mass in place and as a result, guidance
continues to hint at slightly higher temperatures overnight. As a
result, have bumped up temperatures slightly (also supported by
the latest obs/trends) as lows will bottom out in the mid/upper
50s in most locations. The one exception may the sheltered valley
in far northeast Alabama which may drop into the lower 50s.

&&

.SHORT TERM...
(Sunday through Tuesday night)
Issued at 255 PM CDT Sat Apr 13 2024

The synoptic regime discussed above will remain largely unchanged
across our region on Sunday, with broken mid/high-level clouds
and perhaps a couple of light showers continuing for much of the
day and into the evening, before the mid-level shortwave advances
further southeastward (away from the region) and the low-level jet
weakens and veers to WNW early Monday morning. Regardless of the
anticipated increase in clouds aloft, moderately strong SW flow in
the low-levels will lead to highs in the u70s-l80s, with lows
Monday morning once again ranging from the l50s (E) to m-u50s (W).

Boundary layer winds will back to SSE on Monday afternoon and
begin to strengthen on Monday night as a compact mid/upper-level
low tracking eastward across the Four Corners and into the central
Rockies induces a deepening surface cyclone in the lee of the
central Rockies. As this occurs and the blocking ridge to our
south begins to erode from the west, low-level moisture return
will increase across the TN Valley, resulting in low clouds and
perhaps a few light showers Tuesday morning. However, with
forecast soundings still suggesting the development of a notable
mid-level inversion, the risk for more substantial convection will
remain in the vicinity of a developing warm front from the Lower
OH Valley into the southern Appalachians. Highs will remain in the
u70s-l80s on Monday/Tuesday due to the presence of additional
clouds, with lows on Tuesday morning finally warming into the
u50s-l60s.

As the mid/upper-level low ejects northeastward across the
central Plains and into the Upper MS Valley Tuesday/Tuesday night,
a surface trough (likely representing the remnant dryline/Pacific
cold front merger) trailing southward from the related area of
low pressure will shift eastward, reaching the Mid-South region
early Wednesday morning. Clusters of showers and thunderstorms
will likely be occurring in the rapidly strengthening warm
advection regime ahead of this feature, as the southwesterly low-
level jet increases to 50-60 knots. However, the convection may
outpace the return of greater low-level moisture (dewpoints in the
l-m 60s) and may be slightly elevated by the time it reaches our
CWFA. Regardless, it is something we will be keeping our eye on
for the next few days, as impressive vertical shear profiles would
without a doubt support organized/severe thunderstorms in the
presence of sufficient instability.

&&

.LONG TERM...
(Wednesday through Friday)
Issued at 223 AM CDT Sat Apr 13 2024

Afternoon Update: Forecast reasoning for the extended period has
not changed substantially today, and (as mentioned below) showers
and thunderstorms associated with a prefrontal surface trough will
likely continue to progress eastward across our region after
sunrise Wednesday. A separate round of storms may develop along
the actual cold front Wednesday afternoon, which could potentially
spread southeastward into our CWFA Wednesday night and may pose a
risk of severe if the atmosphere can recover in the wake of
morning precipitation. At this point, it appears as if shear will
remain sufficiently strong to support organized convection and
low-level moisture advection may be able to compensate, so this is
something we will continue to monitor, as well. It still appears
as if a secondary/stronger cold front will bring another round of
showers/storms to the region at some point Thursday night or
Friday, but within a weaker flow/shear environment.

By sunset on Tuesday the cold front associated with the
approaching low pressure system will be moving out of the Plains
and into the MS Valley. Rain chances will increase overnight on
Tuesday with best chances for rain (40-60%) associated with the
passage of the cold front Wednesday during the day. There is
currently low confidence in seeing severe weather with this system
as the arrival of rain overnight will have very little
instability to work with and ongoing rain on Wednesday morning
will likely prevent daytime destabilization. Should the timing
speed up, there could be higher chances for strong to severe
storms Tuesday evening.

A brief dry slot will be present on Wednesday night before rain
chances pick back up Thursday afternoon as a secondary cold front
moves through. Better forcing for showers looks to be to our north
leaving us with a prolonged period of low to medium (20-50%) rain
chances from Thursday afternoon to Friday afternoon. Rain chances
drop off Friday evening leaving us with a clear but cool start to
the weekend.

&&

.AVIATION...
(06Z TAFS)
Issued at 1137 PM CDT Sat Apr 13 2024

VFR conditions will prevail at both terminals through the period
as mid-level clouds increase gradually overnight and into the
morning hours on Sunday. Light winds under 10 kts overnight will
become gusty at times on Sunday from the late morning into the
afternoon out of the SW.

&&

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

$$

NEAR TERM...AMP
SHORT TERM....70
LONG TERM....RAD
AVIATION...AMP.24