239
FXUS64 KJAN 250553 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1253 AM CDT Wed Sep 25 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 937 PM CDT Tue Sep 24 2024

Local radars continued to show scattered showers and
thunderstorms across central and east Mississippi this evening.
This activity was southeast of a weak cold front noted near a line
from Winnsboro Louisiana to Grenada Mississippi. Satellite imagery
showed southwest flow aloft across our CWA around a closed low
noted spinning over the mid Mississippi valley. Although the
convection ahead of the cold front has shown a decrease in
intensity the last couple of hours, additional redevelopment will
remain possible into morning as a subtle shortwave within the sw
flow aloft moves overhead. There were a few severe storms that
developed earlier this evening but the additional convection
tonight should remain subsevere. /22/

&&

.DISCUSSION...
Issued at 303 PM CDT Tue Sep 24 2024

Today and Tonight...

The forecast remains on track today: Today`s forecast looks to bring
rain showers (30-50% coverage) and cloudy conditions along a weak
frontal boundary pushing into the area. Current observations
establish the boundary through the southeastern corner of Arkansas
with surface temperatures and dew points lower in central AR. The
upper level dynamics associated with the attendant low have begun to
shift northward, cutting off any major support and therefore chances
for significant deepening and subsequent strengthening of the
feature have diminished. Unsurprisingly, this cut off low, has lost
a lot of momentum and is projected to slowly amble its way through
the region today.

Afternoon heating coupled with an upper level disturbance is
expected to provide lift today to support the develop of scattered
showers with embedded thunderstorms. The line of showers is not
expected to be completely filled in, so some sites may not see any
rainfall today. There is a possibility for isolated strong storms
due to a combination of instability and deep effective shear of 40-
45kts, which have the potential to produce gusty thunderstorms with
small hail. The convective outlook marginal risk area remains just
to our north across northeast Mississippi.

Another lobe of energy is forecast to pivot through the region
during the late parts of tonight and into the early morning
tomorrow. Providing us with a substantial increase in overall
coverage (35%-70%). There`s some indication of slower propagation of
activity during this timeframe which could result in locally higher
rain totals of 1-2".

This afternoon will be our last bout of temperatures breaking into
the low 90s F for the foreseeable feature as the front is expected
to bring widespread cloudiness over the CWA for the next few days.
The incoming regime will establish a more seasonal temperature
profile, with highs in the mid to low 80s F and lows in the low 60s
F.

The 850mb front is expected to stall out over the region, and with
minor overnight retrograding, we will likely see a repeat of today`s
weather over the next few days.

Tomorrow and Thursday...

Light rain showers will be the main topic of discussion as it is
projected to dominate throughout the forecast area Wednesday. The
intensity and coverage will be less impressive tomorrow, as our
major source of ascent will have pivoted around the upstream low and
migrated into TN tomorrow. Hourly rain rates are projected to be at
or below 0.01/hr for all sites, with the exception of the areas
surrounding Winston county which could see totals for the 48 hour
period exceeding an inch.

Thursday Night through Friday Night...

The late week and weekend period will be characterized by an
unorthodox Fujiwhara-like intercyclonic setup. While the low
associated with the aforementioned stalled out frontal boundary
lingers in western TN/central AR, another cyclonic feature, tropical
in nature, will make its way ashore near the Florida panhandle from
the Gulf of Mexico. This unorthodox interplay will have Helene pull
in moisture from the Gulf, rotating around the low before feeding
into the Low in western TN/central AR. The moisture transport around
the mid latitude will feed into and over Tennessee, before the
making its way over the CWA in the form of cloudy residue; since
most the moisture will have rained out before reaching us. That
being said there looks to be a narrow channel of precipitation that
may develop through far east and northern reaches of the area of
responsibility, in the lead up to Helene moving into Georgia.

Saturday through Tuesday...

We look to return to a more typical mid latitude setup as Helene
merges with the cut-off low, and upper level dynamics sweep
southward and begin to pull the low off towards the mid Atlantic
seaboard. A restoration of seasonal weather is in store for the
remainder of the forecast, with highs in the mid to low 80s and lows
in the mid to low 60s F and stark precipitation chances./OAJ/

&&

.AVIATION...
(06Z TAFS)
Issued at 1244 AM CDT Wed Sep 25 2024

Local radars had a few SHRA exiting east MS and a few SHRA across
south MS at 0530Z. Additional development will remain possible but
VFR conditions wl continue to prevail areawide until after 09Z.
After 09Z MVFR/IFR cigs wl develop over the east and south MS TAF
sites and prevail until after 16Z before improving to VFR.
Isolated to scattered SHRA wl remain possible through 18Z as a
weak cold front sags through the area. /22/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       64  80  63  79 /  20  20  20  10
Meridian      64  79  63  79 /  40  30  30  10
Vicksburg     63  81  62  79 /  10  10  10  10
Hattiesburg   67  83  65  84 /  30  20  10   0
Natchez       64  81  61  80 /  10  10  10   0
Greenville    61  78  62  77 /  10  10  20  30
Greenwood     61  81  63  77 /  10  20  30  30

&&

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

$$

/OAJ/22