324
FXUS64 KHUN 121940
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
240 PM CDT Sun May 12 2024

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

.NEAR TERM...
(Tonight)
Issued at 240 PM CDT Sun May 12 2024

Scattered cloud cover currently lingering over the TN Valley is
forecast to increase into the evening hours and overnight as a sfc
low pressure system continues eastward towards our area from the
Central Plains. Temperatures are forecast to drop into the mid 50s
to low 60s tonight with light, variable winds. Just before
daybreak, low chances (30% or less) of showers are possible as
rain moves in from the southwest in response to upper level
shortwaves. More on that in the short term section below.

&&

.SHORT TERM...
(Monday through Tuesday Night)
Issued at 240 PM CDT Sun May 12 2024

Rain chances will increase through the day Monday in response to
an incoming area of sfc low pressure from our west (over the
Central Plains moving into the MS Valley). Ahead of this, a series
of upper level shortwaves will allow low-medium chances (30-60%)
of showers with a low-medium chance of producing lightning
through the afternoon hours Monday. As instability slightly
increases Monday night (along with 6.5-7.0 C/km mid level lapse
rates and ~40-50 kts of 0-6km shear), there is a low chance some
storms may become strong-- bringing threats of gusty to damaging
winds and hail. Confidence in strong storms remains low as the
warm sector track trends to the south of our area (remaining more
in South/Central AL). SPC has placed portions of our CWA
(primarily areas south of the TN River) in a Marginal Convective
Outlook (risk level 1/5) on Monday into Tuesday.

Additionally, model PWATs between 1.3-1.5" would be nearing (just
below) the 90th percentile sounding climatology for BMX. Storm
total rainfall forecast Monday into Tuesday is between 0.5-1.5".
WPC has placed most of our area in a Marginal Excessive Rainfall
Outlook (risk level 1/4) for both Monday and Tuesday. This means
at least a 5% risk of rainfall exceeding flash flood guidance.

Medium-high chances (60-90%) of showers/storms are forecast to
continue Tuesday morning through the afternoon hours before
subsiding from southwest to northeast in the evening. Temperatures
during the short term period will range from the lower to upper
70s for highs with lows in the upper 50s to mid 60s.

&&

.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...
(18Z TAFS)
Issued at 1240 PM CDT Sun May 12 2024

VFR conditions continue this afternoon through the TN Valley with
light, variable winds and increasing cloud cover. Monday morning,
as rain chances return to the TN Valley, periods of MVFR
conditions are possible as ceilings and visibilities decrease.
There is a low chance of lowered ceilings resulting in IFR
conditions, however, confidence is not high enough to include this
in the TAF at this time.

&&

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

$$

NEAR TERM...HC
SHORT TERM....HC
LONG TERM....RSB
AVIATION...HC