784
FXUS64 KJAN 300848
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
348 AM CDT Mon Sep 30 2024

...New DISCUSSION...

.DISCUSSION...
Issued at 347 AM CDT Mon Sep 30 2024

Today & Tonight...

Today: Early this morning, the core of the upper low is parked over
the TN Valley into the Appalachians, the sfc reflection will slowly
wash out. The southwestern trough axis is progged to gradually pinch
off from the core of the low over the Appalachians. Light to near
calm sfc flow & lows dropping into the mid 60s or even exceeding
crossover temps 3-5F into the 61-64F range, dense fog is likely
tonight. Only failure mode could be a combination of low stratus,
which would limit radiational cooling & more widespread dense fog.
However, HREF dense fog probs of 40-60% & gridded LAMP (GLAMP)
probabilities exceeding critical thresholds for several hours,
centered along Hwy 82 from east of Greenwood to Golden Triangle &
southeast. GLAMP exceedance probs don`t extend into I-20 & lower
HREF probs in the 20-30% range are focused there. Based on these
ideas, the Elevated in the HWO graphic was expanded to include along
& east of a line from Sunflower/Leflore into Yazoo County & along &
north of a line eastward into Kemper County in MS. A Significant was
added for the highest HREF dense fog probs >50% in the Hwy 82
corridor from a line east of Leflore to along & north of a line from
Holmes to Noxubee County. These areas in the Elevated/Significant
were also added into a Dense Fog Advisory through 10AM, where some
areas to widespread dense fog are likely. After the fog lifts, a
mostly quiet day is expected, with low stratus & mid to high clouds
gradually clearing, with seasonably warm highs (81-85F north of I-20
& 86-89F along & to the south).

Tonight: As the trough axis pinches off, continued ascent will
persist, but moisture won`t be as prevalent. Clouds shouldn`t be as
much of a forecast concern overnight. Sfc pressure deficits aren`t
as low as this morning, but light to  calm winds should support some
another round of patchy fog. HREF dense fog probs are low but aftn
crossover temps around 3F degrees support patchy fog & potentially
localized patchy dense fog. Held off adding anything additional to
the HWO for now, but if trends persist, will likely need an HWO
graphic for dense fog tonight. Lows will be seasonably warm (63-
68F). /DC/

Tuesday through early next week...

We finally kick this upper low/trough axis in the long term period
with building upper ridging and surface high pressure, warming
temperatures and clearing skies as a result. Pleasant conditions
will persist through much of the week. Rain chances will steadily
increase late Thursday into Friday, mainly south of the I-20
corridor, aided by an active southern jet. The influx of tropical
moisture could potentially lead to heavier rainfall, but flash
flooding does not appear to be a concern for our area as the pattern
suppresses greatest moisture to the south.

Attention then turns to the tropics this weekend as conditions
appear favorable for development in the Caribbean and southern Gulf.
There is good agreement in guidance for a landfalling system
somewhere along the Gulf Coast. However, at this time, it appears
the active southern jet will lead to increased shear for us and help
deflect the system from our area. We will continue to monitor upper
steering patterns and environmental conditions for this potential
system in future forecast updates./SAS/

&&

.AVIATION...
(06Z TAFS)
Issued at 304 AM CDT Mon Sep 30 2024

MVFR vsby & some low stratus/ceilings is psbl across the northern
TAF sites before IFR/LIFR ceilings & dense fog/low vsby develops.
Some areas of VLIFR vsby & localized stratus/ceilings are psbl.
Dense fog/stratus & low flight restrictions will begin to lift by
30/15Z Monday & improve quickly thereafter. VFR conditions are
expected areawide again by 30/17-18Z. Light northwesterly winds,
generally less than 10mph, are expected today. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       85  66  86  65 /  10   0  10   0
Meridian      84  64  86  64 /   0   0  10   0
Vicksburg     87  67  87  64 /   0   0   0   0
Hattiesburg   89  66  89  67 /   0   0   0   0
Natchez       87  67  87  66 /   0   0   0   0
Greenville    84  65  86  62 /  10   0   0   0
Greenwood     84  64  86  62 /  10   0   0   0

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Dense Fog Advisory until 10 AM CDT this morning for MSZ025>033-
     035>039-042>046.

LA...None.
AR...None.
&&

$$

DC/SAS20/DC