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153
FXUS64 KJAN 211922
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
222 PM CDT Sat Sep 21 2024

...New DISCUSSION...

.DISCUSSION...
-- Changed 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/
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&&

.AVIATION...
(18Z TAFS)
Issued at 1239 PM CDT Sat Sep 21 2024

Few to scattered daytime cumulus field has developed around the
forecast area to start the period, with VFR conditions expected to
prevail at the TAF sites through the period. Some patchy BR cannot
be ruled out near some sites around 12Z Sunday, but confidence in
any impacts was too low to mention at this time. /NF/

&&

.PRELIMINARY POINT TEMPS/POPS...
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Jackson       71  93  71  92 /   0   0   0   0
Meridian      70  94  70  93 /   0   0   0   0
Vicksburg     70  94  71  92 /   0   0   0   0
Hattiesburg   71  94  71  94 /   0   0   0   0
Natchez       69  93  70  91 /   0   0   0   0
Greenville    70  93  70  90 /   0   0   0   0
Greenwood     71  94  71  92 /   0   0   0   0
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&&

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

$$

NF/NF/NF