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000
FXUS64 KHUN 210255
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
955 PM CDT Sat Apr 20 2024

...New NEAR TERM...

.NEAR TERM...
(Rest of tonight)
Issued at 955 PM CDT Sat Apr 20 2024

A secondary frontal boundary continues to try to move southeast
this evening. A disturbance moving ENE ahead of it has produced a
large area of rain and some embedded thunderstorms that have pushed
from western Alabama into eastern Alabama over the past few
hours. A widespread area of stratiform rain lingers WNW into
northern Alabama on the back edge of this forcing. So far one
tenth to around one half of an inch has likely fallen near and
south of the Tennessee River in northern Alabama. Most of the
heavier rainfall is currently pushing into Georgia.

The lingering light to moderate rainfall could produce another
tenth to two tenths of an inch of rainfall before we should see a
break and isolated to scattered precipitation chances. Expect
this to happen after 1 AM or 2 AM. Precipitation chances might be
even lower after 1 AM than that.

The next question is whether we will see another round of rainfall
around and after daybreak. Confidence is very low given the spread
of models that this will happen. Especially with the northerly
advection of drier air from Tennessee expected. However, left a 30
percent PoP in after 2 AM.

Winds have dropped a bit, but are still 5 to 10 mph in most
locations. Between this and cloud cover, think that fog will not
be able to form. Also, these two factors should keep temperatures
from dropping much below the upper 40s to around 51 degrees in
a few spots.


&&

.SHORT TERM...
(Sunday through Tuesday night)
Issued at 240 PM CDT Sat Apr 20 2024

Present indications are that light rain (associated with the
third/final wave discussed above) will be ending rather quickly
from W-to-E between 12-18Z Sunday, with partial clearing expected
to occur for many locations tomorrow afternoon. However, due to
weakening but persistent cold advection in the boundary layer,
highs should still only reach the u50-l60s. A broad ridge of high
pressure at the surface will begin to shift eastward across the
southern Plains on Sunday night, but the pressure gradient to the
east of the ridge`s center will likely maintain at least some
mixing in the lower troposphere locally, and this along with some
high clouds related to the passage of a longwave trough axis may
reduce impacts from radiational cooling with dewpoints in the l-m
30s. Although this scenario would lower concern for frost
development early Monday morning, a patchy coverage of frost will
still be possible (mainly across southern Middle TN, where lows
are forecast to be in the m-u 30s).

The center of the surface ridge will shift eastward across the TN
Valley and into the central Appalachians on Monday, before
building further northeastward and off the northern Mid-Atlantic
coast on Monday night. This will provide a period of clear skies,
light winds and dry conditions, with highs returning to the m-u
60s Monday before falling back into the u30s-l40s Monday night.
Southwesterly return flow will become established on Tuesday and
Tuesday night as a weakening northern stream trough and surface
low track southeastward across southern Ontario and the Great
Lakes. This will allow for a gradual increase in both dewpoints
and temperatures, but mostly clear skies and dry conditions will
prevail through 12Z Wednesday.

&&

.LONG TERM...
(Wednesday through Friday)
Issued at 303 AM CDT Sat Apr 20 2024

Afternoon Update: Based on the 12Z suite of global models, all
thoughts mentioned in the extended discussion (below) remain valid
this afternoon.

High pressure will get squeezed to the southeast mid to late
week, with a couple of weak impulses pushing across the area each
day. However, very limited moisture will keep the forecast dry,
with only scattered to broken bands of cloud cover being the main
impact. Temperatures each day will peak in the low to mid 70s,
with lows in the upper 40s to lower 50s. A pronounced longwave
trough over the western United States will slowly progress
eastward late this week into the weekend. This will be the next
feature to watch as it may bring our next decent chances for
showers/storms by next weekend.

&&

.AVIATION...
(00Z TAFS)
Issued at 603 PM CDT Sat Apr 20 2024

VFR CIGS are expected at both terminals through 2Z. Then expect
RA or -RA to affect KMSL before spreading east to the KHSV terminal
by 3Z. Expect persistent rain for about 3 or 4 hours, before a
secondary frontal boundary pushes this rainfall south of the
terminals. During this period some MVFR VSBYS due to rainfall is
expected, but CIGS should remain VFR. CIGS in the MVFR or lower
range look to stay well south of the terminals. Winds will become
more N or NNE and winds will pick up to around 10 knots with some
gusts up to 18 knots at times through 5Z or 6Z. Winds should
relax a tad after midnight, but still remain around 10 knots.
Thus, fog is not expected overnight. Winds should pick up again
after daybreak to around 10 knots gusts to between 15 and 20
knots.

&&

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

$$

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