681
FXUS64 KJAN 220534 AAC
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1234 AM CDT Sun Sep 22 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 1001 PM CDT Sat Sep 21 2024

Not much to talk about in the evening update. Weather conditions
will remain quiet for the next several hours thanks to the sfc high
pressure remaining centered over the Southern Appalachians and
southeastern CONUS. HREF guidance is hinting at some patchy fog
development mainly for areas south of I-20 starting a little after
midnight. Sky conditions will be generally clear across central MS
allowing for radiational cooling to occur our forecast area. Because
of this, overnight lows will drop into the 70s with areas east of I-
55 dipping into the upper 60s. Updates are out. /CR/

&&

.DISCUSSION...
Issued at 221 PM CDT Sat Sep 21 2024

Through Monday:

Upper-level ridging will prevail over Northern Mexico and the Gulf
Coast region as surface high pressure remains centered over the
Southern Appalachians and southeastern CONUS. The pattern should
keep our forecast area on the dry side of any disturbances passing
to the north.

Tuesday through Saturday:

By Tuesday, the synoptic pattern will become much more complex. The
ridge is expected to nudge eastward toward the southeastern CONUS
with a positively-tilted trough axis deepening across the Plains
states in its wake. This pattern change will at least allow for some
increase in POPs Tuesday especially for our northwestern and western
zones Tuesday as a cold front dips in and another shortwave ripples
past in the flow aloft. Showers and possibly a few thunderstorms
could develop heading into the daytime.

What transpires Wednesday into the end of the week is a bit trickier
to nail down. As the upper-level ridge gets locked near Florida,
model guidance is picking up on the likelihood that the trough cuts
off an upper-level low pressure system around the High Plains to mid-
Mississippi River Valley region while the remaining northern stream
energy continues eastward. At the same time, the energy and moisture
associated with a Central American Gyre will be pivoting northward
from the western Caribbean toward the Gulf of Mexico. Whether any
closed tighter circulation can develop from this gyre remains a
question, but the National Hurricane Center`s latest assessment of
the situation places a 60% (Medium) chance for development of a
Tropical Depression in the next 7 day time frame. This essentially
covers the potential time frame of concern for the Gulf Coast
region, as the latest suite of model guidance show the envelope of
moisture and energy arriving toward the Gulf Coast in a Thursday to
Saturday time frame. The exact way the upper trough, ridge, and gyre
interact will ultimately determine when and where the impacts of
heavy rain and/or winds are felt in the Gulf region. But at this
point it remains a period of concern as portions of the region have
experienced heavy rain associated with Francine, and areas of higher
soil moisture as seen on MRMS, etc. could increase the potential for
flooding if and when heavy rain develops. Individual model runs will
remain highly variable due to the uncertain nature of these synoptic
features.

For now, please remain aware of developments in the forecast,
especially if traveling around the Gulf Coast region through next
weekend. /NF/

&&

.AVIATION...
(06Z TAFS)
Issued at 1234 AM CDT Sun Sep 22 2024

VFR flight categories will prevail at area TAF sites over the
next 24 hours. Winds overnight will be calm, but will increase
through morning from the south and southwest at around 5 knots.
/19/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       93  71  92  71 /   0   0   0  10
Meridian      94  70  93  70 /   0   0   0   0
Vicksburg     94  71  92  71 /   0   0   0  10
Hattiesburg   94  71  94  70 /   0   0   0   0
Natchez       93  70  91  70 /   0   0   0   0
Greenville    93  70  90  70 /   0   0   0  20
Greenwood     94  71  92  71 /   0   0   0  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

$$

19