480
FXUS64 KHUN 010124
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
824 PM CDT Fri May 31 2024

...New NEAR TERM...

.NEAR TERM...
(Tonight)
Issued at 824 PM CDT Fri May 31 2024

Looking at the earlier 7 PM sounding from BMX, drier air is still
in place below 700 mb. Very saturated above that level though
through the remainder of the sounding. PWATS in that sounding were
at 1.42 inches. The warm front to our south hasn`t moved much,
but has inched northward slightly. It currently extends from
between KEET and KTCL NNW through central Franklin county (AL) to
Savanah (TN). An area of heavier showers and a few thunderstorms
formed along it a few hours ago that produced a quick 0.25 to 0.80
inches of rainfall in those areas. Further east, dewpoint
depressions (10 to 20 degrees still) are indicative of the airmass
that was still in place in the BMX sounding. Thus, mainly we have
had just cloud cover and virga in areas east of the warm front.

This activity is much lighter now and the heavier precipitation is
forming more southwest of this boundary currently. The majority of
the stronger lift in the atmosphere right now is concentrated west
of the area over central and northern Mississippi. Several models
continue to show this stronger forcing remaining in central MS
and that area of showers and embedded thunderstorms expanding and
spreading more northerly than to the east over the next 3 to 5
hours. However, shortly after 1 AM, several models depict the
upper low over eastern Kansas shifting slightly further east. As
it does so, additional shortwaves moving along its southeast
periphery make it far enough east so that the eastern portion of
this area of showers and embedded thunderstorms makes it into
northwestern Alabama in a more persistent manner. No shear is in
place over the area and don`t expect any much of the night. There
is some elevated instability present west of the I-65 corridor
(around 500 to 1000 J/KG). So will likely see at least a few
embedded thunderstorms continuing as that activity moves into NW
Alabama after 1 AM.

As this occurs, Corfidi vectors at and near the surface do oppose
the mean flow, so some backbuilding of showers and thunderstorms
looks like a possibility. With PWATS climbing to over 1.7 inches
towards daybreak and the stronger forcing continuing to move
further east into the Alabama, some ponding of water on roadways
and possibly isolated flash flooding could occur. Shear does
increase to around 30 to 35 knots at 7 AM. However, not expecting
any surface based instability to be in place and only very meager
elevated instability. Overall increased precipitation chances
overnight, especially after 1 AM. Not expecting many thunderstorms,
but a few elevated storms could occur. Also, raised low temperatures
slightly (lower mid 60s west), but kept a decent gradient in far
northeastern Alabama (58 to 62), with more SE flow expected much
of the night (given the drier airmass in that location upstream).

A more pronounced flash flooding/river flooding concern and a low
end threat for severe weather may develop later in the day on
Saturday.

&&

.SHORT TERM...
(Saturday through Monday)
Issued at 313 PM CDT Fri May 31 2024

For the weekend and early next week, an unsettled pattern is
forecast with chances for showers and thunderstorms in the
picture. The ARW/FV3 and longer term models all indicated numerous
to widespread showers and thunderstorms impacting the area on
Saturday. With plenty of cloud cover and high rain chances,
temperatures will trend cooler than today. Highs Sat should only
warm in to the mid/upper 70s. The NBM`s low/mid 70s looked too
cool so boosted them up a few degrees.

The heaviest showers move more to the east Sat night with lesser
rain chances expected Sunday. Rainfall totals over the area should
range from 1/2" east to over 1.5" west. The higher amounts of rain
over our western areas could run-off, resulting in a risk of
flooding and flash flooding. The Weather Prediction Center has a
slight risk for our western 2/3s of our area on Sat, main due to
runoff from Fri night into Saturday morning rain totals. With more
sun peeking through, high temperatures to start the new week
should rise into the lower 80s. Convection chances appear to
become more on a diurnal trend, with higher odds Monday afternoon.

&&

.LONG TERM...
(Monday night through Thursday)
Issued at 219 AM CDT Fri May 31 2024

A shortwave across the TN Valley will start off the unsettled
pattern that will persist through mid week. An upper level trough
in the Northern Plains will develop a sfc low and associated cold
front on Tuesday. Another shortwave will slide out ahead of this
system to keep low chance (20-30%) of showers and storms in the
forecast through Tuesday. The sfc low will remain up in the Great
Lakes or just north of there, the cold front will push southeast
into the region on Wednesday. We will see an uptick in the
coverage of showers and storms (30-50%) before the front pushes
through on Thursday. Not expecting severe storms at this time, but
will monitor trends as we get closer to the event.

Ahead of the front, daytime highs will start off in the lower 80s
and climb to encroach 90 degrees by Wednesday with lows around 70
degrees. Behind the front, temps will only slightly improve.

&&

.AVIATION...
(00Z TAFS)
Issued at 553 PM CDT Fri May 31 2024

A narrow line of showers continues to develop well southwest of
the KMSL terminal at this hour. Expect this activity to mainly
move NNW and not affect the terminal through 02Z. However, kept a
PROB30 group in in case this activity expands far enough eastward
during that period. Expect the bulk of rain and thunderstorms to
move northeast into the KMSL terminal closer to 08Z and the KHSV
terminal around 09Z, expect CIGS to drop to MVFR or lower around
that timeframe. This should be a persistent and widespread area
of RA and -TSRA. Southeast winds around 10 knots should increase
early this evening and especially after midnight (sustained around
10 knots with gusts to 20 knots). A timeframe of 10Z to 14Z at
the KMSL terminal and 12Z to 16Z was highlighted for heavier -TSRA
for now. During this period, some IFR or lower CIGS or VSBYS
could occur. Expect conditions to improve some after these tempo
groups, when VSBYS or CIGS could become predominantly MVFR again.

&&

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

$$

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