853
FXUS64 KHUN 181418
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
918 AM CDT Sat May 18 2024

...New NEAR TERM...

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

As a sfc 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 sfc
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...
(12Z TAFS)
Issued at 526 AM CDT Sat May 18 2024

Cloud cover at both terminals has kept mist/light fog from
forming and reducing VSBYS into the MVFR realm. However, a low
stratus deck has formed around and below 1000 feet. Expect this to
remain in place through 15z or 16Z, before an area of -TSRA and
TSRA move towards the KMSL terminal. Expect this activity to
approach KMSL around 13Z and CIGS to lift a little, but likely
not above 1500 feet. The timing of the first tempo group for IFR
VSBYS and -tsra was delayed to between 13Z and 15Z for this
activity at KMSL and an hour later at KHSV based on radar trends.
A second round of heavier TSRA is still expected, but again
delayed. The predominant -SHRA VCTS was delayed to begin at 15Z
at KMSL and 16Z at KHSV. A second tempo group for TSRA was kept at
both terminals but again delayed to between 17Z and 21Z.

&&

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

$$

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