193
FXUS64 KHUN 140455
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1155 PM CDT Sat Jul 13 2024

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 858 PM CDT Sat Jul 13 2024

Isolated showers that formed across parts of the area in the
afternoon have dissipated. The convection formed, thanks to strong
daytime heating and resultant instability. While showers did not
directly impact the official sites, a number of backyard weather
stations around the Tennessee Valley have recorded amounts ranging
from a few hundredths of an inch, upwards to over 1/2 inch in some
spots.

High temperatures across the area earlier soared into the mid 90s
to 100 degree. Muscle Shoals and Decatur apparently heated to 100
degrees, with 98 the high in Huntsville. Other locations were more
in the mid 90s. Temperatures as we near 9 PM have cooled into 70s
and 80s. Given the heat from earlier and a very warm airmass in
place, lows by daybreak Sunday should cool into the lower to mid
70s, with light winds. Fog could become an issue in the overnight
mainly in/near locations that received a "wetting" rain (~> 1/10
of an inch). But the overall area has been trending on the dry
side, with most if not all of the moisture absorbed into the
ground and vegetation. Big changes to the on-going forecast are
not needed at this time.

&&

.SHORT TERM...
(Sunday through Monday Night)
Issued at 1238 PM CDT Sat Jul 13 2024

The weak vorticity center in eastern TX into northern LA/southeast
AR is forecast to lift northeast into northern MS and AL Sunday
and linger through Tuesday. This will continue to erode the
already weak capping inversion. Thus, we will maintain a 10-15%
PoP Sunday once again for isolated convection, and slowly increase
those PoPs into Monday, especially for the southern counties in
our forecast area. Steep low level lapse rates will create a
favorable environment for gusty winds with associated downdrafts.
Will go with near persistence temperature forecasts with highs in
the middle 90s to around 100. With strong mixing, dew points will
continue to be halted in the upper 60s to around 70 during the
afternoon hours, producing heat index values below 105 degrees for
most areas.

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 417 AM CDT Sat Jul 13 2024

The most recent suite of global models suggests that conditions
on Tuesday will be very similar to Monday, with highs in the m-u
90s, heat indices in the 100-105F range and a 20-30% coverage of
afternoon showers and storms (which will likely be slow-moving and
capable of producing heavy rainfall in localized areas). By
Wednesday, however, our region will experience increasing
influence from an amplifying northern stream trough, which is
predicted to spread northeastward from Ontario into the Canadian
Maritime provinces by Thursday night/Friday morning. The cold
front related to this trough is expected to advance southeastward
during the middle portion of the week, with the prefrontal wind
shift axis expected to slowly cross the TN Valley at some point
Wednesday night or Thursday. A higher (60-80%) POP for showers
and thunderstorms is warranted as early as Wednesday afternoon
given the position of the front to our north and strengthening WNW
flow aloft. The greater coverage of convection will likely
continue on Wednesday night/early Thursday morning, before
becoming focused to the south/east of the wind shift (across our
southeastern zones) on Thursday afternoon. Due to some uncertainty
regarding the location of the front before it eventually stalls,
we will maintain a medium chance POP in the southeastern portion
of the CWFA on Thursday night and Friday. Fortunately, a modest
coverage of clouds and precipitation should keep highs in the
u80s-l90s from Wednesday-Friday, lowering the heat risk region-
wide.

&&

.AVIATION...
(06Z TAFS)
Issued at 1155 PM CDT Sat Jul 13 2024

VFR conditions continue through the TAF period at both KMSL and
KHSV. A low chance of fog exists this morning along large bodies
of water, however, confidence is low in this affecting TAF sites.
Therefore, it has been left out of the TAF issuance. Amendments
may be needed if fog forms near the terminals.

&&

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

$$

NEAR TERM...RSB
SHORT TERM....17
LONG TERM....70
AVIATION...HC