549
FXUS64 KMEG 242026
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
326 PM CDT Tue Sep 24 2024

...New SYNOPSIS, DISCUSSION...

.SYNOPSIS...
Issued at 326 PM CDT Tue Sep 24 2024

An unsettled weather pattern will prevail across the Midsouth
during the middle and late portions of the week. A deep upper
level low pressure system will move into the Midsouth on
Wednesday, and move only little through Saturday. This upper low
will bring a rainfall into the upcoming weekend, aided by
moisture from the remnants of what will likely become Hurricane
Helene. High temperatures will prevail in the 70s Wednesday
through Saturday.

&&

.DISCUSSION...
(This evening through next Monday)
Issued at 326 PM CDT Tue Sep 24 2024

Mid-afternoon GOES water vapor imagery showed a closed upper low
developing over the MO River Valley. A belt of strong southwest
flow aloft was evident southwest of the low, extending from
southern AR through the OH River Valley. SPC Mesoanalysis
indicated 45 knots of effective bulk shear across northeast MS,
coincident with 2500 J/kg of mixed layer CAPE. A Marginal severe
threat will continue across the northeast MS into portions of
southern west TN into early evening, before CINH increases and
upper level divergence zone shifts east into AL.

Tropical Storm Helene is forecast to intensify into a major hurricane
on Thursday, before making landfall over the FL panhandle Thursday
evening. Thereafter, Helene will make a fairly quick path through
the Southeast, aided by southerly flow ahead of the synoptic
closed low over the Midsouth. Helene`s remnant low will weaken
after passing through the southern Appalachians. But the remnant
low and tropical moisture will become entrained into the northern
side of the synoptic low by Thursday night. PWAT values near 2
inches and the potential for training will result in a Slight Risk
for excessive rainfall over west TN and northeast MS late Thursday
into early Friday.

The synoptic low will weaken and lift into OH Valley on Sunday.
Some light wrap-around showers will be possible Sunday and Monday,
mainly to the north and east of Memphis. Thereafter, a northern
branch trough will drop from the Canadian prairie into the Great
Lakes. There remains some spread in global models with respect to
the amplitude of this trough and resultant northwest flow across
the Midsouth. But at this time, there appears to be a better than
even chance of a cold frontal passage around the middle of next
week. Autumn-like dewpoints in the 40s and 50s may be on the
horizon.

PWB

&&

.AVIATION...
(18Z TAFS)
Issued at 1220 PM CDT Tue Sep 24 2024

Current satellite imagery shows a trough digging through the
region this morning with associated clouds. So far, only
intermittent drops to MVFR have been seen across E AR. Have
included FEW025 to account for any drops into MVFR at JBR/MEM
through 00z.

Otherwise, the most notable impact through this afternoon will be
TS in the vicinity of MKL/TUP. A cold front is currently in E AR
and will continue eastward throughout the period with storms
forming along it. Convection is expected to persist in the region
through at least 22z up until 00z this evening.

Overnight, clouds should generally lower in coverage before post-
frontal CIGs at 10 kft overspread the region. Some visibility
drops are possible in MKL, so kept 4 SM for now with changes being
possible in subsequent TAFs. Otherwise, VFR is likely to prevail
for much of the remainder of the period at all sites with a
clearing trend through tomorrow.

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$

PUBLIC FORECAST...PWB
AVIATION...JAB