411
FXUS64 KHUN 300708
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
208 AM CDT Tue Apr 30 2024

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

.NEAR TERM...
(Today)
Issued at 208 AM CDT Tue Apr 30 2024

Showers and embedded thunderstorms will continue to track east
through the local area this morning, ahead of a weak cold front
currently approaching the lower MS River Valley/lower OH River
Valley. These storms will be efficient rainfall producers given
PWATs above 1.5" and the slow forward progress thanks to weak
shear. 6 hourly rainfall estimates by radar show between 2-3
inches have fallen across far NW AL, and this is supported by
several ground observing sites in the area. Despite the heavy
rainfall amounts, relatively dry grounds should mitigate most if
not all flooding concerns through the morning hours as these
showers/storms slowly clear the area to the east. Severe weather
is not expected given weak synoptic forcing and shear. Overnight
runs were consistent with previous forecasts, having dry
conditions return to the area shortly after noon with clearing
skies several hours before sunset. The sun should help us warm
into the mid 70s to lower 80s this afternoon, with the warmest
temperatures over NW AL where more hours of direct sunlight is
expected.

&&

.SHORT TERM...
(Tonight through Friday)
Issued at 208 AM CDT Tue Apr 30 2024

High pressure will begin to shift east into the area late this
afternoon into tonight. The main concern tonight will be fog
development lasting into the morning commute hours. Given recent
rainfall, clear skies, and light winds... will be a favorable
setup for fog in at least the usual fog prone river valleys. Will
have to monitor closely overnight in case a Dense Fog Advisory is
needed. Upper ridging/high pressure will keep conditions warm and
dry through Thursday, with daily highs in the mid to upper 80s
and lows in the lower 60s. Southerly flow will bring increasing
moisture to the area Thursday night ahead of our next system,
resulting in increasing clouds and low chances (20-30%) for
showers and storms over NW AL.

&&

.LONG TERM...
(Friday night through Monday)
Issued at 208 AM CDT Tue Apr 30 2024

The latest suite of global model guidance suggests that the TN
Valley will remain beneath a region of light and generally
unamplified WSW flow aloft throughout the duration of the extended
forecast period, featuring mid-level wind speeds of 25-30 knots
at most. In the low-levels a warm/moist airmass will reside across
the region, with dewpoints expected to be in the l-m 60s on
Friday/Saturday, before perhaps rising into the m-u 60s on
Sunday/Monday. This will yield seasonably high values of CAPE
(particularly during the afternoon hours, when boundary layer
temperatures should rise into the l-m 80s). At this point, it
appears as if coverage of showers and thunderstorms will be
highest on Friday afternoon/evening, which is the timeframe when a
weak cold front may drift southeastward into the CWFA prior to
stalling. The front may indeed remain in the region for much of
the day on Saturday (warranting a continuation of low-medium
chances for showers and storms), before returning northward on
Sunday as an amplified trough in the northern stream induces
cyclogenesis in the lee of the northern Rockies. Although the
atmosphere will be moderately unstable each day, vertical wind
shear will not be conducive for the development of organized
convection and lightning/locally heavy rainfall should be the
primary storm impacts.

&&

.AVIATION...
(06Z TAFS)
Issued at 1103 PM CDT Mon Apr 29 2024

There have been no significant changes to previous aviation
forecast reasoning, as prevailing MVFR cig and vsby conds are
anticipated for an extended period thru 11-13Z as a band of mod-
hvy rain and embedded TSRA shifts eastward across northern AL.
Although the trailing/western edge of the precipitation band will
end within the timeframe noted above, additional but more
scattered shower activity is possible prior to the arrival of a
frontal wind shift to NW late tomorrow morning. A more pronounced
clearing trend will begin late Tuesday aftn, with clear skies and
lgt/vrbl winds perhaps resulting in the initial development BR/FG
btwn 4-6Z.

&&

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

$$

NEAR TERM...25
SHORT TERM....25
LONG TERM....70/DD
AVIATION...70/DD