504
FXUS64 KJAN 161439 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
939 AM CDT Mon Sep 16 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 916 AM CDT Mon Sep 16 2024

Early fog is dissipating as we head into midmorning and a band of
generally light showers continues across northern into eastern
Mississippi. Showers and thunderstorms will likely reinvigorate as
we warm into the upper 70s F to middle 80s F late morning and
into the afternoon and scattered to widespread rains are likely.
This activity will diminish after dusk. Fog will be possible
again tonight as lows dip into the 60s F for most. /86/

&&

.DISCUSSION...
Issued at 415 AM CDT Mon Sep 16 2024

Today through tonight: Primary weather concerns in the near term
include fog development (this morning and possibly again Tue
morning) and the potential for locally heavy rainfall over mainly
the northeast half of the area.

Concerning fog: Fog has developed as expected over mainly the
southwest half of the forecast area in the humid boundary layer,
and will keep the current limited dense fog graphic going as a
few observations of dense fog are being noted. May need a dense
fog advisory for some locations, but it seems overall, visibility
is remaining above a 1/4 mile. Given the persistent pattern and
weakening low level flow, another round of fog will be possible
early Tue morning.

Concerning rainfall: A persistent rex block type weather pattern,
anchored by a strong high centered over the Great Lakes/New
England areas and a low that has persisted over the Lower MS
Valley region, continues in the near term. The latest guidance
indicate that the low will fill and weaken as a potential tropical
cyclone near the South Atlantic coast takes over as the primary
low circulation in the rex block pattern. Before the weakening
fully takes place, a highly moist convergence axis (precipitable
water ~ 1.9 inches) in southeast low level flow will maintain a
band of showers over east central/north central MS. Highly
localized heavy rainfall rates are possible, but flash flooding
is generally not expected with weakening low.

Otherwise, given considerable cloud cover and areas of rainfall,
temperature ranges will be somewhat small and a below climatological
normal. /EC/

Tuesday through early next week: Early morning hi-res guidance
continue to show a stalled frontal boundary along the Gulf Coast.
This combined with the presence of tropical moisture will allow
for afternoon/early evening scattered showers/thunderstorms
generally south of I-20. Forecast confidence is much higher
compared to the previous day as the latest GFS/NAM holds on rain
chances through Tuesday evening. Current HREF guidance is starting
to hint at some widespread patchy fog potential across much of
our forecast area. Went ahead and added fog into the forecast for
Tuesday night/early Wednesday morning. Could see a Dense Fog
Advisory being issued around this timeframe if things pan out. Fog
trends will continued to be monitored as we get closer to Tuesday
evening.

Heading into Wednesday, global guidance continues to show a rex
block pattern evident of over the east CONUS which should keep our
forecast area dry and help suppress any rain potential. In addition,
temperatures could climb into the upper 80s with a few spots across
the NW Delta reaching in the low 90s. Went ahead and bumped up
temperatures slightly given 850 mb temps (between 14 and 16 deg C)
supportive of a slightly warmer solution. With the ground moist from
leftover rain and stagnant conditions expected, patchy fog is likely
for the next few days. By Sunday, warm conditions will make a return
to the area with slightly above normal temperatures near 90/70
returning to the area. Heading into the new work week, future global
guidance hints at a upper low pushing east across the Ohio River
Valley. On the southern periphery of the upper low is a cold front
that is forecasted to push east across the Southern Plains and
towards the southeast CONUS. This combined with limited tropical
moisture from the Gulf will re-introduce some low end rain chances
(between 15-20%) mainly for areas along and east of I-55 by
Monday afternoon. /CR/

&&

.AVIATION...
(12Z TAFS)
Issued at 653 AM CDT Mon Sep 16 2024

Poor aviation weather with considerable IFR/LIFR categories due to
to low stratus/fog/rain will impact the forecast area for much of
the period. Primary concerns for fog will be over southwest
portion of the area early this morning, with primary SHRA concerns
over northern/eastern portions of area through the forecast. The
greatest chance for improving to VFR will be from late this
morning through afternoon, but another round of stratus/fog is
likely late tonight in this persistent pattern. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       82  68  85  67 /  80  60  30   0
Meridian      80  66  86  65 /  90  50  20   0
Vicksburg     83  68  85  67 /  50  40  20   0
Hattiesburg   85  70  86  69 /  70  70  50   0
Natchez       85  68  84  68 /  40  20  30   0
Greenville    79  66  85  64 /  70  50  10   0
Greenwood     80  66  87  65 /  70  30   0   0

&&

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

$$

LP/CR/EC