299
FXUS64 KMEG 220511
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1111 PM CST Sat Dec 21 2024

...New AVIATION...

.UPDATE...
Issued at 836 PM CST Sat Dec 21 2024

Latest surface analysis places a 1036 mb ridge of high pressure
over Ontario. This is resulting clear skies and cold temperatures
in the 30s across the Mid-South this evening. Overnight lows
will drop into the 20s overnight with excellent radiational
cooling expected. Temperatures will be adjusted slightly mainly
east of the Mississippi River to account for short-term trends.
Otherwise the remainder of the forecast is in excellent shape.

CJC

&&

.SYNOPSIS...
Issued at 158 PM CST Sat Dec 21 2024

Cool and dry conditions continue through at least Monday. Tuesday
begins a period of more active weather with daily rain chances and
temperatures above normal in the 50s and 60s.

&&

.DISCUSSION...
(This evening through next Friday)
Issued at 158 PM CST Sat Dec 21 2024

All is cool and calm across the Mid-South this afternoon as
northerly flow in the wake of high pressure is keeping
temperatures in the 40s. Expect essentially a repeat of this
tomorrow, though a smidge warmer due to a more southerly component
in the wind. Temperatures will begin their upward climb tomorrow,
not stopping for the foreseeable future. We`ll be waking up to mid
20s tomorrow morning, but this is the coldest morning of the
forecast period by far.

Beginning on Tuesday, the pattern starts to become a little more
active. A messy surface pattern with a warm front lifting north
from the ArkLaTex and a cold front over the Ozarks will cause a
wide swath of showers to overspread the Mid-South throughout the
day, continuing through Christmas evening. Unfortunately, we`ll
have no shot at a white Christmas as ground temps will be near 50
degrees throughout all this rain. Though much of the Christmas Eve
and Day will be a washout, QPF totals through Dec 25 are
generally around a half inch.

The upper level pattern gets a bit more interesting by the end of
the week. A large and potentially negatively tilted trough looks
to eject from the Four Corners early Friday morning. Regardless of
how the parameter space evolves, the 500 mb pattern is suggesting
a large area of southwest flow aloft with strong upper level
divergence somewhere between the Central Plains and the Mid-South
on Friday evening. It`s worth noting that this trough`s timing has
trended a little slower, which would mitigate severe weather
potential for us on Friday. However, there are several potential
scenarios depending on which LREF cluster plays out, and it`s
worth noting that each cluster is weighted pretty much equally. In
other words, it`s really a toss up at this point what kind of
kinematics we`re going to be working with. I will note that the
ensemble mean joint probability of CAPE > 300 J/kg and bulk shear
> 25 kts (a very conservative threshold for organized
thunderstorms) is quite low (less than 10%) for the Mid-South
Friday and Saturday, but it is certainly something to watch for as
this system evolves.

CAD

&&

.AVIATION...
(06Z TAFS)
Issued at 1109 PM CST Sat Dec 21 2024

Nice flying wx. Light E winds veering to SE on Sunday.

&&

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

$$

PUBLIC FORECAST...CAD
AVIATION...SJM

NWS MEG Office Area Forecast Discussion