054
FXUS64 KHUN 191418
AFDHUN

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

...New NEAR TERM...

.NEAR TERM...
(Rest of Today)
Issued at 918 AM CDT Fri Jul 19 2024

A shortwave moving through the area today accompanied by around
1000 J/KG of CAPE already present in BMX 12Z sounding is
supporting a morning round of showers and storms moving NE through
the area. As the shortwave continues to progress throughout the
day, medium to high rain chances will be present. Best chances for
rain and storms will be south of the TN river as storms propagate
north of the cold front located just south of the CWA border.

Storm coverage should increase through the afternoon with the
atmospheric profile favorable for gusty winds, frequent lightning,
and heavy rain. Based on HREF model soundings, some storms may
have the potential to become strong to severe but this will
likely be highly contingent on the evolution of morning storms.
All showers and storms should begin to erode just after sunset
with the loss of surface heating.

&&

.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...
(12Z TAFS)
Issued at 647 AM CDT Fri Jul 19 2024

Scattered to at times numerous showers and a few storms will move
across the TN Valley. Higher rain chances timing appears will
occur into the late afternoon, as an upper level disturbance moves
by. Have for the most part stayed VFR far as reduced CIG/VSBY
given the precip is convection, with VSBY reduced into the MVFR
range this afternoon. Did not mention of gusty winds with low
confidence in timing...this could be added in later updates.
Shower activity should wane this evening as the disturbance
moves away. A warm front heading northward tonight, along with
residual moisture from recent rainfall could result in the
development of low clouds and/or fog after midnight. Did trend
down with CIGs, but not enough confidence to add a fog mention in
the TAFs latter hours.

&&

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

$$

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