943
FXUS64 KHUN 091632
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1132 AM CDT Sun Jun 9 2024

...New AVIATION...

.NEAR TERM...
(Rest of Today)
Issued at 910 AM CDT Sun Jun 9 2024

Complex weather setup today across the Tennessee Valley. Early
morning convection has quickly waned in a stable environment over
north Alabama. However, over southern Missouri another MCS is
waiting in the wings as it continues to push ESE into portions of
the Mid South and lower Ohio Valley. This feature is tied to
another mid-level shortwave and it`s associated surface cold
front. Guidance continues to keep broken cloud cover in place over
much of the area for the remainder of the morning -- hindering
heating and destabilization somewhat. However, by early/mid
afternoon, these clouds shouldn`t be an issue with HiRes showing
temperatures climb into the 85-90 degree range and SBCAPE values
of 2000-3000 J/kg. This unstable environment will be primed for
severe weather -- especially when we`ll add 30-40 kts of bulk
shear from the approaching shortwave trough.

The uncertainty lies with with where and how convection will
evolve upstream today. Current thinking is that a remnant outflow
boundary from storms currently over southern Missouri will
initiate storms over north central Arkansas sometime early this
afternoon. This activity will then push ESE with the mean flow
across northern Mississippi, congealing into an MCS. Eventually,
this feature will approach and move into portions of north and/or
central Alabama by the evening hours -- depending on the
trajectory of the MCS and where/when it forms upstream. Should
storms be able to move into the Tennessee Valley, a favorable
environment for damaging winds and at least marginally severe hail
will exist -- along with the threat for locally heavy rainfall.
Timing will need to be refined throughout the day by watching
radar/satellite trends, but the main window may end up being a 6
PM to 11 PM timeframe from northwest to southeast.

&&

.SHORT TERM...
(Tonight through Tuesday night)
Issued at 422 AM CDT Sun Jun 9 2024

We will carry a medium-high (50-70%) POP in the grids early this
evening to reflect the potential for both convective regimes
(discussed above) to continue for a few hours past sunset, and
although POPs begin to decrease after Midnight, a narrow band of
showers (and perhaps a few thunderstorms) will accompany the
actual cold front as it shifts southward across the forecast area.
Present indications are that the front will exit our southeastern
zones between 12-15Z Monday, with any lingering shower activity
expected to end with its passage. By Monday, afternoon,
strengthening NNW winds will advect a cooler/drier Canadian
airmass into the region, with dewpoints falling back into the mid
50s as temperatures struggle to reach the u70s-l80s. This will set
the stage for a clear and cool night, featuring lows in the m-u
50s early Tuesday morning. Temperatures will exhibit little
fluctuation on Tuesday and Tuesday night, with dry conditions
continuing as a low-amplitude mid-level ridge translates eastward
ahead of a weak southern stream trough tracking east-southeastward
over OK/TX.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 422 AM CDT Sun Jun 9 2024

Although specific details remain unclear at this point, most of
the global models now suggest that that southern stream trough
(discussed above) will travel southeastward into the northern Gulf
of Mexico during the first half of the extended period, before
evolving into nearly stationary cutoff low on Friday/Friday night.
Any northward movement of the low next weekend will likely be
dictated by the strength and orientation of a blocking mid-level
ridge to its north, which will in all likelihood lie across the TN
Valley, providing an extended period of warm and dry conditions
that could potentially extend into the first part of the following
week. That said, we have included a very low (15-20%) POP across
our southeastern counties on Friday and Saturday afternoons, due
to a gradual increase in low-level moisture which will translate
to a notable increase in CAPE given hot daytime temperatures.
Highs will quickly warm into the lower 90s for most valley
locations by Thursday/Friday/Saturday, with lows more gradually
returning to the u60s-l70s by Saturday morning.

&&

.AVIATION...
(18Z TAFS)
Issued at 1132 AM CDT Sun Jun 9 2024

VFR conditions will be the predominant flight category this
afternoon as a front approaches the region from the NW. Model
guidance hints that a cluster/line of storms may develop and push
into the region during a 23-05z timeframe. Have handled this with
a TEMPO group for reduced visibilities and ceilings from TSRA
during this timeframe. AWWs and amendments may also be needed if
this occurs. TSRA chances will wane after Midnight and VFR
conditions will return by Monday morning.

&&

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

$$

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