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000
FXUS64 KHUN 181031
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
531 AM CDT Thu Apr 18 2024

...New AVIATION...

.NEAR TERM...
(Today)
Issued at 113 AM CDT Thu Apr 18 2024

Low clouds have developed and/or overspread much of the area this
morning. The exception is far northeast AL which is the last
location yet to be clouded over. Thus, patchy dense fog has
developed in this area. At this point, expect the low clouds to
win out over fog the rest of the morning, but will keep a close
eye on it.

For today, the low clouds will eventually lift and scatter by late
morning or midday. Temperatures should warm rather quickly due to
heating and warm advection, with highs in the lower to middle 80s
as minor upper ridging translates east across the region. This
will be closely followed by a fast-moving low amplitude shortwave
crossing the MS river by mid afternoon. This wave is displaced
from the wave moving through the lower MO and upper MS valleys.
Initial clusters of showers and thunderstorms will develop this
afternoon as the wave approaches, in combination with increasing
theta-E advection, mainly in northwest AL.

&&

.SHORT TERM...
(Tonight through Sunday)
Issued at 113 AM CDT Thu Apr 18 2024

The threat of a few strong to severe storms will increase this
evening as the shortwave moves into the middle TN and AL. Forecast
soundings indicate SBCAPE reaching 1500-2000 j/kg and 6km bulk
shear of 30-40kt should be sufficient for supercells with large
hail and damaging wind the main hazards. That`s round 1.

Round 2 may come very late tonight into Friday associated with a
cold front. If anything, bulk shear may increase to 40-45kt with
CAPE values potentially going above 2000-3000 j/kg ahead of the
front. The front and storms should exit before sunset.

With flow in mid to upper levels becoming more zonal over the
weekend, multiple weak shortwave impulses may bring a few showers
Saturday afternoon and night. The greatest chances of rain and
perhaps a few thunderstorms in our far southern counties will be
on Sunday as a more pronounced shortwave tracks east through eh
Gulf states. The highest chances for steady rainfall will be in
our southern counties, with lower chances in southern TN and far
north AL. And it will be a chilly rain at that, with highs only in
the 50s.

&&

.LONG TERM...
(Sunday night through Wednesday)
Issued at 113 AM CDT Thu Apr 18 2024

Monday will be dry but still cool with highs in the 60s as high
pressure at the surface overspreads the OH and TN valleys. Dry
weather should last through Tuesday with temperatures warming
back into the 70s. On Wednesday, upper troughing resulting from a
strong upper low in Quebec and Ontario, will bring a cold front
south through the TN valley. At this point, leaning toward a dry
forecast, but it is borderline and may need further changes later
if the models come into better agreement.

&&

.AVIATION...
(12Z TAFS)
Issued at 530 AM CDT Thu Apr 18 2024

Ceilings below 010agl (IFR) and in some cases below 005agl (LIFR)
may also accompany patchy BR and FG. Visibility of 1/2SM and less
will occur in a few locations. The ceilings will lift or scatter
by 16-17Z, improving conditions to VFR. Scattered SHRA and TSRA
will develop and move into northwest AL by 22Z and move east
across the rest of north AL and southern middle TN through 04-06Z.
This will drop ceilings below 030agl and visibility to 3SM or less
(MVFR) at times. An additional line of TSRA will arrive after 06Z
from northwest to southeast, once again lowering ceilings below
020agl (MVFR).

&&

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

$$

NEAR TERM...17
SHORT TERM....17
LONG TERM....17
AVIATION...17