203
FXUS64 KHUN 010157
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
857 PM CDT Tue Apr 30 2024

...New NEAR TERM...

.NEAR TERM...
(Tonight)
Issued at 857 PM CDT Tue Apr 30 2024

Under the influence of upper level ridging, dry weather remains
in place overnight as lows drop into the mid to upper 50s. With
calm winds and clear skies in place, our biggest talking point
tonight is fog formation. Current dew point depressions are
between one to ten degrees through the TN Valley. As we continue
into the morning hours, we have medium confidence in fog formation
through at least the rivers/valleys of northern AL and southern
middle TN. Elsewhere, we have a low chance of patchy fog
formation. Visibilities will be monitored closely and any
widespread fog formation will be treated with a subsequent SPS or
Dense Fog Advisory. If fog does form, it should dissipate shortly
after sunrise during the late morning hours.

&&

.SHORT TERM...
(Wednesday through Thursday night)
Issued at 151 PM CDT Tue Apr 30 2024

High pressure will become established across the Tennessee Valley
Wednesday and Thursday, promoting mostly sunny and dry conditions
both days. In fact, a pronounced warm-up will take place,
especially by Thursday as the mid/upper ridge axis begins to
amplify and winds veer to a southerly direction. In response,
highs will climb into the mid 80s on Wednesday and the mid to
upper 80s again on Thursday. It`s not completely out of the realm
of possibility that a couple of sites reach the 90 degree mark
(ensembles hint at about a 10% chance of exceeding that value at
both MSL and HSV). Cloud cover will begin to increase by Thursday
evening and especially late Thursday night as another mid/upper
trough swings into the Great Lakes -- with its associated cold
front shifting through the mid/lower Mississippi Valley. Low to
medium (20-40%) chances for rain showers (and a few elevated
storms) are forecast late Thursday night into Friday morning ahead
of the front. QPF amounts are expected to be light, however, as a
bulk of the precipitation (and higher rain chances) will move in
after 12z Friday. More on this in the section below.

&&

.LONG TERM...
(Friday 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...
(00Z TAFS)
Issued at 608 PM CDT Tue Apr 30 2024

VFR conditions will continue at KMSL and KHSV through the TAF
period, however, a low chance of fog exists in the early morning
hours Wednesday. If this occurs, MVFR conditions are possible at
both KMSL and KHSV. Any fog that does form should dissipate
shortly after sunrise, in the late morning hours.

&&

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

$$

NEAR TERM...HC
SHORT TERM....AMP
LONG TERM....70
AVIATION...HC