118
FXUS64 KHUN 190744
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
244 AM CDT Fri Jul 19 2024

...New NEAR TERM, SHORT TERM, LONG TERM...

.NEAR TERM...
(Today)
Issued at 244 AM CDT Fri Jul 19 2024

Showers have diminished to just isolated activity at this hour.
The showers were quite efficient rain producers in a few
locations given the PW near 2 inches. Rain amounts of 2-3+ inches
were reported in portions of Limestone County earlier Thursday
evening. The surface cold front has slipped into central AL, with
drier surface dew points in the middle 60s dipping into the far
northwest AL and southern middle TN. Patchy fog has developed in
areas that received rainfall, so will monitor that trend over the
next few hours.

For the rest of today, a shortwave in Lousiana will slowly move
east through MS into AL this afternoon. The stronger QG forcing
with this will remain just to our south, but the very moist
airmass even north of the surface boundary will be supportive of
at least scattered showers and a few thunderstorms, mainly during
peak afternoon heating. CAMs vary quite a bit on this today, so
have kept PoPs a bit conservative and below categorical. However,
locally heavy rainfall will occur, especially due to slow
movement. Given the clouds and precipitation, high temperatures
should be held in the lower 80s for most areas.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 244 AM CDT Fri Jul 19 2024

Any showers and thunderstorms should decrease in coverage this
evening with loss of daytime heating. The shortwave will be
shifting east into GA tonight as well. Through this weekend, 5h
and 8h flow will remain west to southwest with a mean trough
remaining over the central U.S. This will keep a very moist
airmass in place, and daily mainly afternoon and early evening
showers and thunderstorms are expected. Mesoscale boundaries along
with the weak surface front now to our south will certainly
factor in on eventual initiation areas. Overall, the greater
chances will be in our southeast counties due to the proximity of
the surface front which seems to hang up in this area. CAPE
values will be a bit higher Saturday and Sunday afternoons, when
a few strong thunderstorms can expected. But, locally heavy
downpours will be the primary hazard given the high PWs and slow
movement. However, the overall suggested blended PoPs seem a bit
high given weak forcing. Thus have brought those back just a bit,
but staying in the medium/likely range. High temperatures will be
in the middle to upper 80s with lows in the upper 60s to lower
70s.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 244 AM CDT Fri Jul 19 2024

A wetter and cooler change from the generally dry and hot summer is
expected for much of the new workweek. A frontal boundary which is
currently south of the area, will translate northward over the
weekend. It should move north of the area on Sunday, and remain into
the new week. The boundary`s northward movement will in part be
induced by troughing amplifying southward from the Great Lakes, with
the upper highs displaced to over the Desert SW and NW Atlantic
Basin. With the surface front to our north, a lower level southerly
flow will bring deep moisture from the Gulf of Mexico more inland.
This should produce precipitable water amounts into the 2" or higher
range over and near the Tennessee Valley for this period.

Thus we will have better opportunities for more of the area to
receive much needed rainfall. With the higher moisture values and no
real focusing mechanism, have stayed with a diurnal trend regarding
rain chances, with the best chances in the afternoon hours. Given
that the precipitation will be as showers, have trimmed down from
categorical (75-100%) chances to likely (55-74%), as not all areas
will experience rainfall. Even so, higher rain chances should help
temper some of the drought. Rainfall totals of 1.75" to nearly 3.00"
could fall in the Mon-Thu timeframe. Until more heavy rainfall
impacts the area, am not pushing a flood threat at this time. That
said, areas that experience locally heavy rains could experience
ponding of water, with flash flooding a non-zero chance.

With more clouds than sun and good rain chances, recent summer hot
temperatures will apparently be taking a break next week, with highs
in the 80s. In this issuance, we have highs in the mid/upper 80s
Mon/Tue, and in the low/mid 80s Wed/Thu.

&&

.AVIATION...
(06Z TAFS)
Issued at 1052 PM CDT Thu Jul 18 2024

Isolated -SHRA will persist at times through Friday morning.
Ceilings will remain above 030agl (VFR) except within
precipitation areas. Chances of SHRA and TSRA will go up to medium
by 16-18Z during the peak heating hours. Activity may linger after
00Z in a few locations, but confidence in this affecting either
KHSV or KMSL is too low to include at this time.

&&

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

$$

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