977
FXUS64 KMEG 150830
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
230 AM CST Fri Nov 15 2024

...New SYNOPSIS, DISCUSSION...

.SYNOPSIS...
Issued at 230 AM CST Fri Nov 15 2024

Rain-free conditions will continue through Sunday with showers
likely Monday into Monday night. Relatively cool temperatures are
expected today with highs in the upper 50s to lower 60s. A gradual
warm-up will occur through early next week, but a strong cold
front will bring much cooler air into the region late in the week
with highs in the 40s and lows in the 30s.

&&

.DISCUSSION...
(Today through Thursday)
Issued at 230 AM CST Fri Nov 15 2024

Some early morning fog will result in visibilities reduced to 1/2
mile or less at times. This fog will generally remain patchy and
tied to low-lying areas or near bodies of water. We`re not
anticipating a Dense Fog Advisory at this time, but we`re keeping
a close eye on trends.

A split-flow synoptic pattern will dominate the weather pattern
through the weekend. This will provide rain-free conditions
through Sunday with rain chances quickly ramping up to start the
new work week. The Mid-South will end this week on the cool side
with lows this morning in the low/mid 40s and highs in the upper
50s to lower 60s. We will experience a gradual warming trend
through early next week as a ridge builds over the Gulf of Mexico.
The deterministic NBM is generally in good shape in the near-term
though minimum temperatures in interior West TN early Saturday
morning will be shaved down closer to the 50th percentile. The
dry, post-frontal air mass and light winds should allow
temperatures to drop quickly after sunset. Max temperatures look
to climb into the lower 70s across much of the CWA by Sunday ahead
of the next system.

This next system appears quite strong. As the aforementioned ridge
noses into the Ohio Valley this weekend, a potent, positively-
tilted trough will dig over the western CONUS. Ensemble guidance
indicates 500-mb heights within this trough near the 1st
percentile over northern Mexico by Sunday. However, a strong
upper-tropospheric jet will develop downstream of the closed low,
causing the cyclone to fill and lift quickly to the northeast
across the Plains early next week. A lee cyclone will develop late
Sunday, racing northeast toward the Corn Belt on Monday as it
occludes. This will induce strong meridional flow in the warm
sector, enhancing low-level thermal and moisture advection. The
NAEFS is indicating precipitable water briefly approaching the
97th percentile Monday night. South winds will be gusty Monday and
Monday night. Deterministic winds remain below Wind Advisory
criterion (sustained winds of 25 mph or greater) but the hourly
NBM data indicates around a 20% chance of exceeding this threshold
(and gusts of 40 mph) across portions of northeast AR and
southeast MO.

There remains some disagreement in the global ensembles on the
timing and strength of this trough as it ejects into the central
CONUS early next week. However, ensemble clusters really don`t
indicate a significant difference in QPF timing or amounts due to
these differences. The inner quartile of NBM rainfall amounts
Monday and Monday night generally ranges from 0.25 to 0.75" with
slightly higher amounts across north MS (75th percentile is near
1.25" at Tupelo).

The upper-level low will consolidate into a broader, polar branch
trough moving into the Northern Plains on Tuesday. This trough
will close off by midweek, moving southeast and eventually
settling over the eastern CONUS as a ridge builds over the west.
This may result in an unsettled period of weather with a chance
for rain showers during the midweek period as a couple of
vorticity lobes rotate around the trough and interact with
instability enhanced by the cold temperatures aloft and a
reinforcing cold front. Coverage looks to be very spotty mid/late
week with minimal QPF. Daytime temperatures will certainly be
cooler during the latter half of the week. Highs may struggle to
reach 50 degrees Thursday and Friday with overnight lows in the
30s. Some areas may experience that first freeze (which is well
past the climatologically favored time for a large majority of the
Mid-South). The NBM-based probability of temperatures of 32F or
less ranges from 40-60% Friday and Saturday morning across West
TN and northeast MS, with lower probabilities elsewhere across the
CWA.

MJ

&&

.AVIATION...
(06Z TAFS)
Issued at 1120 PM CST Thu Nov 14 2024

Patchy fog may result in MVFR conditions overnight at MKL. High
resolution guidance also favors the development of MVFR ceilings
at MKL Friday morning. Otherwise, VFR conditions and light winds
expected to prevail through the period at TAF sites.

&&

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

$$

PUBLIC FORECAST...MJ
AVIATION...CJC