580
FXUS64 KHUN 181053
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
553 AM CDT Thu Jul 18 2024

...New AVIATION...

.NEAR TERM...
(Today)
Issued at 403 AM CDT Thu Jul 18 2024

Patchy, dense fog has developed in portions of northeastern AL
with the assistance of clear skies and calm winds. Visibilities
are forecast to continue decreasing through the area with the
arrival of storms moving through north-central AL along an outflow
boundary this morning. Clearing behind this boundary will allow a
low chance (20-30%) of patchy fog throughout the remaining areas
of northern AL. If this fog becomes more widespread and/or dense
in nature, an SPS or Dense Fog Advisory may be considered. Any fog
that forms is forecast to dissipate shortly after sunrise (by
around 9 AM CDT).

Today, medium to high chances of showers/storms (40-60%) are
forecast once again as a frontal boundary stalls to our southeast.
Any storm that forms will be capable of producing lightning,
moderate to heavy rainfall, and gusty winds. Due to the multiple
rounds of showers/storms, a low end flooding threat exist today.
The Weather Prediction Center has almost our entire forecast area
outlined in a Marginal Excessive Rainfall outlook (threat level
1/4) meaning there is at least a 5% risk of rainfall exceeding
flash flood guidance through Friday morning. We encourage everyone
to have multiple ways to get warnings and avoid driving in flooded
roads.

The rain and ongoing cloud cover through the day brings continued
relief from the heat as highs will be capped in the upper 80s with
heat indices in the 90s.

&&

.SHORT TERM...
(Tonight through Sunday)
Issued at 403 AM CDT Thu Jul 18 2024

Showers/storms remain in the forecast through the short-term, with
medium-high chances daily. Due to the front stalling southeastward
of our area, higher rain chances remain south of the Tennessee
river. Rain chances are forecast to peak during the
afternoon/evening hours, aided by diurnal heating, but are
possible during both the daytime and nighttime hours with multiple
rounds forecast. Lightning, moderate to heavy rainfall, and gusty
winds will be threats with any strong storm that forms through the
weekend. In addition to this, a low end flooding threat continues
to be possible. WPC has placed most of our area in a Marginal
Excessive Rainfall outlook (threat level 1/4) Friday morning into
Saturday morning meaning there is at least a 5% risk of rainfall
exceeding flash flood guidance. Due to the weak shear in place,
severe weather is not forecast at this time. However, we encourage
everyone to check back in for forecast updates as we approach this
weekend.

Highs during this time are forecast to peak in the 80s with
overnight lows in the 60s-70s. Heat indices will continue to
remain below 100, reaching the upper 80s to mid 90s.

&&

.LONG TERM...
(Sunday night through Wednesday)
Issued at 403 AM CDT Thu Jul 18 2024

Sunday evening, an upper level longwave trough will be the main
focus as it extends from the Great Lakes to the southeastern Plains.
A subtropical ridge over the Central Atlantic will keep this
trough in place through the mid week. This will allow the
Tennessee Valley to remain in a favorable environment for multiple
rounds of rainfall as southwesterly flow aloft moves over the
area, bringing PVA. PWATs in the 1.8-2.0" are forecast in the LREF
50th percentile range, which would near or exceed the 90th
percentile sounding climatology per BMX. Any storms that form
during this time will likely be efficient rainfall producers and
bring a continued threat for flooding.

&&

.AVIATION...
(12Z TAFS)
Issued at 553 AM CDT Thu Jul 18 2024

Vicinity showers are forecast to continue near KHSV this morning,
however, VFR conditions will prevail. A medium chance for MVFR
conditions is possible this afternoon as lowered ceilings and
visibilities accompany shower/storm chances at both KMSL and KHSV,
which have been added as TEMPO groups between around 19-22Z. VFR
conditions are set to return by 03-04Z this evening, however, a
low chance of MVFR conditions is possible at KHSV early Friday
morning due to increased thunderstorm chances returning and
bringing lowered ceilings and visibilities back to the airport.

&&

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

$$

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