771
FXUS64 KJAN 121458
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
958 AM CDT Fri Jul 12 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 958 AM CDT Fri Jul 12 2024

Heat and humidity will be on the rise yet again today as mid morning
global guidance continues to highlight a 591dam high to our south
and a upper level trough to our north. Current GOES-16 visible
satellite imagery show some mid to high level clouds from our
southwest starting to track northeast towards our forecast area.
Both of these features are expected to shift off to the east later
in the afternoon. This will allow for a mid-level high to
strengthen and become the dominant feature across central MS. The
mid to high level clouds will do very little to suppress daytime
heating across the region with afternoon highs forecasted to peak
in the mid to upper 90s. The slight increase of low-level moisture
from the Gulf combined with daytime heating will lead to some
isolated/scattered showers and storms south of I-20, with slightly
higher pop chances (between 35-40%) along and south of Hwy 84.
Elsewhere, the northern half of our CWA will remain dry with heat
indices reaching below 105 deg. /CR/

&&

.DISCUSSION...
Issued at 358 AM CDT Fri Jul 12 2024

Today and Tonight: It will be a little warmer and a little more
humid today and tonight. Early morning water vapor imagery/RAP
analysis still showed our CWA between a 591dam high to our south and
an upper level trough to our north. Flow around these features were
drawing some mid and high level clouds up from our southwest. Both
of these features will shift east through the period and the mid
level high will strengthen and become more dominant over our CWA.
Early morning surface analysis still had a 1017mb ridge across our
CWA and a nearly diffuse stalled boundary across our southern zones.
The mid and high level clouds will do little to keep temperatures
from climbing up into the mid 90s at most locations. The increase in
low level moisture from the south, combined with the daytime heating
will lead to isolated to scattered showers and thunderstorms this
afternoon nearly to the Interstate corridor. The northern half of
our CWA is expected to remain dry. Some of the convection will
linger into early evening before dissipating. Temperatures tonight
will bottom out in the lower 70s at most locations which is close to
normal. /22/

Saturday through late next week: Temperatures and dewpoints will
gradually increase this weekend as upper ridging and corresponding
surface high build into the area. Temps aloft will increase into
the low 20s C, which should result in surface temps in the upper
90s, with a few 100s in some spots. Highest temperatures appear
concentrated along the HWY 82, where a drier airmass should allow
for deeper mixing. A heat advisory will likely be needed
eventually for this weekend with heat indices of 105-110. As high
pressure shifts east early next week, Gulf moisture will creep
northward. As dewpoints increase Monday-Wednesday, heat indices
increase to 110+. Excessive heat warnings will likely be needed
for portions of the area early next week, especially in the Delta
where dewpoints appear to hold in the mid 70s longer. With greater
moisture, afternoon convection chances should become more
numerous. Still, heat will likely be an issue prior to convective
initiation. Will continue to carry limited/elevated heat messaging
in HWO for this weekend and early next week.

By late next week, strong upper ridging builds over the western
CONUS, forcing an upper trough over the eastern CONUS to dig
southward. Some this cooler, drier airmass may make it to our far
northern areas, however most of the area should remain under a SW
flow regime given the positive tilt of the trough. With moist Gulf
air sticking around late next week, heat indices may remain
elevated, especially further south. Will hold off on heat messaging
for late next week at this time, but may eventually be needed
should confidence increase./SAS/

&&

.AVIATION...
(12Z TAFS)
Issued at 627 AM CDT Fri Jul 12 2024

Other than isolated to scattered TSRA this aftn in the se, VFR
conditions and a light wind will prevail through the TAF period.
/22/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       95  74  96  76 /  10  10  40  10
Meridian      98  73  99  75 /  10  10  30  10
Vicksburg     95  73  96  75 /  10   0  30  10
Hattiesburg   96  75  97  76 /  40  10  50  10
Natchez       93  74  94  75 /  20  10  40  10
Greenville    95  73  97  76 /   0   0  10   0
Greenwood     96  73  98  75 /   0   0  10   0

&&

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

$$

22/SAS/22