009
FXUS64 KHUN 181730
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1230 PM CDT Sat May 18 2024

...New AVIATION...

.NEAR TERM...
(Rest of Today)
Issued at 918 AM CDT Sat May 18 2024

As a low pressure system moves into the TN Valley from the west,
a complex of storms accompanies it- bringing threats of lightning,
large hail, gusty to damaging winds, and heavy rainfall/flash
flooding this morning into the afternoon. While most CAMs are
failing to initialize well enough to give a decent solution on how
this event will progress, the 3km NAM shows continued development
this morning into the afternoon/evening. With MUCAPE values
potentially reaching 2000+ J/kg in addition to sufficient lapse
rates (7.0-7.5 C/km), strong updrafts will support hail growth as
the storms move through the area. PWATs are 1.5-1.6", reaching the
90th percentile sounding climatology at BMX and proving these
slow-moving storms to be heavy rainfall producers. Due to the very
weak shear in place (less than 20 kts), we are not forecasting
tornadoes to be a threat at this time. Storms should subside late
this evening as the aforementioned low continues to move eastward
into the Carolinas. Otherwise, high temperatures today will peak
in the upper 70s to low 80s under broken to overcast cloud cover.

&&

.SHORT TERM...
(Tonight through Tuesday)
Issued at 226 AM CDT Sat May 18 2024

Most guidance moves the upper low and upper level trough axis into
northern Georgia and southern Alabama this evening. Wrap around
shows and a few embedded thunderstorms could persist though in
northern Alabama and southern middle Tennessee. These storms
should not be severe given the lack of shear present and declining
instability. These showers and thunderstorms could last until
around midnight before pushing further east into Georgia.
Slightly drier air behind the departing trough axis and surface
front should allow lows to drop into the 60 to 65 degree range as
you wake up on Sunday morning.

Guidance continues to move this upper low east and drag the
surface front southeast through the day on Sunday. The result
should be a nice day across much of northern Alabama and southern
middle Tennessee. Some morning clouds should give way to mainly
partly cloudy skies in the afternoon. Clouds and a 20 to 30
percent chance of an afternoon shower or thunderstorm will pop
back up far eastern portions of Alabama (due to the back edge of
forcing from the upper low to our east/afternoon instability). Not
expecting to see much development though or any of these storms
if they develop to become severe. This insolation should allow
highs to climb back into the lower to mid 80s.

Sunday night light winds and clear skies are expected across the
area. This could allow lows to drop into the upper 50s to lower
60s. A warmup begins on Monday, as strong upper level ridging
starts to build over the area. 925 mb temperatures climb into the
lower 20s in the afternoon. With sunny skies, temperature will
likely climb into the mid to upper 80s (maybe a tad higher).

&&

.LONG TERM...
(Monday night through Friday)
Issued at 226 AM CDT Sat May 18 2024

Dry and warm conditions will continue into Tuesday, as upper level
ridging amplifies over the area. Highs should approach 90 degrees
in a few places. Lows should only drop into the mid 60s to near
70 Tue night.

A storm system forecast to form over the Rockies and adjacent
High Plains over the weekend will head to the NE, reaching the
Great Lakes on Wednesday. A cold front trailing south of it will
move across the area on Wed. Moisture convergence and lift
preceding it will return medium chances (30-50%) of showers and
thunderstorms beginning Tue night. Unsettled weather with
scattered showers and thunderstorms will remain in the forecast
into Thursday. Overall storm strength should remain "general" with
a risk of strong outflow wind gusts, heavy downpours, and sudden
and/or frequent lightning. Even with more clouds and rain chances,
high temperatures on Wed/Thu should range in the mid/upper 80s,
and lows in the 60s.

&&

.AVIATION...
(18Z TAFS)
Issued at 1230 PM CDT Sat May 18 2024

MVFR conditions should continue to prevail through the afternoon
into the evening hours as storms continue through the TN Valley
from the west, bringing lowered ceilings and periods of lowered
visibilities. Overnight, depending on cloud cover, a low chance of
patchy fog exists. If this is realized, lowered visibilities will
continue to cause MVFR to IFR conditions at both terminals.

&&

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

$$

NEAR TERM...HC
SHORT TERM....KTW
LONG TERM....RSB
AVIATION...HC