253
FXUS64 KHUN 082339
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
639 PM CDT Wed May 8 2024

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 254 PM CDT Wed May 8 2024

A dynamic and complex weather event is unfolding across portions
of the mid MS and lower OH River Valleys, and will continue to
track south closer to the Tennessee Valley this evening. A
deepening low over the central US will continue to drive strong
southwesterly flow aloft and increasing low level flow will
enhance WAA closer to the sfc. A warm and very unstable airmass
exists ahead of a cold front, and any thunderstorms that are able
to form in this environment will be primed for quick
intensification and capable of producing all severe hazards.

We believe the initial threat for strong to severe storms will
come from supercells progged to develop to our west over western
TN and MS. The evolution of these storms has been fairly
inconsistent within high-res guidance, with early afternoon trends
favoring an initially discrete storm mode at initiation and then
congealing into a broken line or line of thunderstorms with
embedded supercells. These storms will have the ability to
produce large hail and damaging winds due to the favorable
combination of instability and shear. A tornado threat will also
exist, especially with more isolated supercells that can tap into
the stronger low-level helicity. The primary timing for this round
will be between 7pm and 2am.

This round will be followed by a more organized line of storms
later tonight - knocking on the door of NW AL around 2-3am -
through the early morning hours. Damaging winds and large hail
will be the primary concerns from any storms that form this
evening and tonight, but tornadoes and localized flooding are also
possible. This remains a low confidence forecast and is largely
dependent on the evolution of the mesoscale environment and the
amount of thermodynamic support available overnight.

Lastly, a flooding threat will linger into the morning hours as
storm total rainfall amounts of 1-2" are expected area-wide, with
localized amounts up to 3-5" possible. The highest chances for
flooding will be in southern middle TN and areas north of the TN
River.

Confidence in seeing severe weather in the Tennessee Valley
tonight is medium to high, while confidence in which round will be
the more severe is lower. The degree of instability available
overnight will be a critical factor and will be largely dependent
on airmass recovery between rounds of thunderstorms. Please check
back frequently for updates and have multiple ways to receive
warnings that are capable of waking you up. With this being an
overnight event, the threat to life and property will be
heightened.

&&

.SHORT TERM...
(Thursday through Saturday)
Issued at 254 PM CDT Wed May 8 2024

Showers and storms will gradually come to an end from north to
south Thursday morning, and the severe threat should diminish by
10am at the latest. High pressure will begin to filter into the
region Thursday into the weekend, resulting in dry and cooler
conditions. A weak shortwave will track across central MS into
central AL Thursday night into Friday morning and could result in
a few showers/storms mainly south of the TN River, but confidence
in this remains low. Highs will be limited to the 70s Friday
afternoon with clearing skies and breezy northwesterly winds.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 437 AM CDT Wed May 8 2024

A generally dry weather pattern will continue across the region
this weekend. However, a clipper system diving southeastward into
the western Great Lakes will send a reinforcing cold front through
the region on Saturday, perhaps bringing a few light showers to
locations north of the TN River. Chances for rain will begin to
slowly return to the region as early as Monday, which is when a
series of lower-latitude troughs may initiate the development of
one or more areas of low pressure across the western Gulf of
Mexico that would shift northeastward early next week. Due to
indications of a modifying low-level airmass across the TN Valley,
instability will gradually increase as we move forward to
Tuesday, with a low chance for thunderstorms apparent as well.

&&

.AVIATION...
(00Z TAFS)
Issued at 639 PM CDT Wed May 8 2024

VFR conditions will continue until thunderstorms develop around
00-01Z. Expecting two rounds of thunderstorms, the first batch
around 00-01Z then again around 08Z. These storms could become
severe and bring higher wind gusts and IFR/LIFR VIS at the
terminals when directly impacted. Main threats within these storms
overnight will be frequent lightning, wind gusts up to 50-60kts,
and large hail. Gradient winds sustained at 12-15kts with gusts up
to 25kts will also be possible outside of any thunderstorm
activity. Otherwise, CIGS will return to VFR mid day Thursday.

&&

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

$$

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