778
FXUS64 KHUN 121112 AAA
AFDHUN

Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
612 AM CDT Sun May 12 2024

...New AVIATION...

.NEAR TERM...
(Today)
Issued at 330 AM CDT Sun May 12 2024

Upper ridging and surface high pressure will continue to keep
rain out of the forecast for today. Cloud cover will begin to
increase this afternoon as a surface low pressure system moves
over the central Plains. Light winds will also become more
southeasterly and begin to usher moisture into the Tennessee
Valley this evening. As for temperatures, highs this afternoon are
expected to reach the upper 70s to around 80 degrees. Overall, no
significant weather impacts are anticipated today. Enjoy the day
and Happy Mother`s Day!

&&

.SHORT TERM...
(Tonight through Tuesday Night)
Issued at 330 AM CDT Sun May 12 2024

Upper ridging this weekend will push eastward as an upper
trough/cutoff low moves over the Mississippi Valley through the
day on Monday. This feature will then continue to progress east
over the Ohio Valley through midweek. Meanwhile, a series of
shortwaves look to move along the base of this trough (generally
over the Deep South and up into our area) Monday night through
Tuesday. At the surface, high pressure will be pushed over the
eastern seaboard on Monday as a low pressure system over the
central Plains traverses the Mississippi Valley and Ohio Valley
through midweek. The associated warm front still looks to be to
our south by Tuesday morning, but the parent low will then move
northeast over the region through the day. Therefore, a portion of
our area may be in the warm sector Tuesday afternoon. Overall,
anticipating chances for showers to begin to increase area-wide
late tonight (20-50% chance). High chances (50-80%) of showers and
storms will then comprise most of the day on Monday. Medium to
high chances of showers and storms are forecast to continue
through Tuesday, with the highest chances Tuesday afternoon
(80-100%).

Guidance has begun to indicate that instability values will begin
to increase Monday night and peak Tuesday afternoon, with
instability exceeding 1000 J/kg along with bulk shear around 50
knots. Although, not seeing too much in the way of 0-1 km or 0-3
km SRH at this point. The instability and shear coincides with the
trajectory of the aforementioned surface low (with portions of
our area in the warm sector Tuesday afternoon). Although, synoptic
guidance seems to suggest that the better upper support (more
substantial upper shortwaves and upper jet between 60-70 knots)
will occur over the northern Gulf coast. Ultimately, we will
continue to monitor this system; but, damaging winds, hail, and
frequent lightning will all be possible with the storms on
Tuesday. SPC has outlooked areas generally southeast of the
Tennessee River in a Marginal Risk of severe weather on Tuesday.
Additionally, forecast total rainfall at this point ranges between
1-1.5 inches, with locally higher amounts possible. Model PWATs
range from 1.3-1.5 inches Tuesday morning through the afternoon,
which are between the 75th and 90th percentiles for BMX sounding
climatology. Therefore, showers and storms will be efficient
rainfall producers and may lead to some minor flooding concerns.
WPC has most of our area outlooked in a Marginal Risk of excessive
rainfall.

Chances for showers and storms will then quickly diminish from
southwest to northeast Tuesday night, with low to medium (20-60%)
chances Tuesday evening decreasing to low/very low (0-20%) by
Tuesday night. As for temperatures, highs will be mild on Monday
(upper 60s to lower 70s). It will then be a bit warmer on Tuesday
as temperatures top out in the upper 70s to around 80 degrees.
Meanwhile, lows tonight will range in the mid 50s to lower 60s.
Increasing moisture will result in warmer low temperatures Monday
night (in the lower to mid 60s). Lows are then forecast to only
drop into the lower 60s Tuesday night.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 330 AM CDT Sun May 12 2024

An upper level low currently over western Colorado will progress
eastward, and should be moving over the eastern Ohio River Valley
at the start of this period as a weakening trough. The main
surface low should be moving over the VA/MD region, while a weaker
low and boundary remain over eastern Tennessee. The presence of
this front and remaining moisture will help bring isolated to
scattered showers and thunderstorms Wed afternoon for the eastern,
and much of the central areas. The area of low pressure and
moisture should exit further to the east Wed night, and bringing a
brief dry period on Thu.

Another system nearing the area from the west will bring more
shower and thunderstorm chances starting Thu evening over our far
western areas, with the activity overspreading the area overnight
Thu and on Fri. Have maintained likely (60-70%) rain chances on
Fri. Output from some of the medium range guidance, especially the
ECMWF/Canadian were hinting that some of the storms Fri
afternoon/evening could become strong, with high outflow winds the
main threat. Precipitable water amounts at and above 1.5" at this
time could lead to locally heavy rain, with localized flooding a
possibility. Despite the passage of a frontal boundary early Sat,
residual moisture remaining will help continue showers as we close
out the week.

Clouds and showers on Wed will keep highs in the mid/upper 70s. A
return of more sun early Thu and a southerly flow should help
push highs into the lower 80s on Thu. Highs around 80 are expected
Fri and Sat. Low temperatures in the mid/upper 50s Wed night will
moderate into the 60s Thu and Fri nights.

&&

.AVIATION...
(12Z TAFS)
Issued at 612 AM CDT Sun May 12 2024

No rain is anticipated during the day today and into this
evening, but rain chances are expected to increase from the west
later tonight. Additionally, MVFR conditions are forecast to
develop late tonight into early Monday morning for the MSL
terminal. Decreasing CIGs to MVFR will follow for HSV around 12Z
as well; however, as this was outside of the forecast period, did
not mention in the TAF at this time. Light and variable winds
today will become southeasterly through this evening and generally
be around 5 knots. Although, winds are expected to begin to
increase around 12Z.

&&

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

$$

NEAR TERM...26
SHORT TERM....26
LONG TERM....RSB
AVIATION...26