397
FXUS64 KJAN 130543
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1243 AM CDT Sat Jul 13 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 1227 AM CDT Sat Jul 13 2024

Forecast remains mostly on track. Some isolated showers have
lingered in the vicinity of the HWY 84 corridor, so opted to add
low end pops in this area over the next couple hours./SAS/

&&

.DISCUSSION...
Issued at 306 PM CDT Fri Jul 12 2024

Tonight and Tomorrow...

No changes have been made to the forecast for the short term period.
The upper level trough to our north will continue to shift off to
the east heading into the overnight period as the sfc high over the
southwest CONUS remains in a somewhat stationary position. At the
same time, a 594dam ridge to our south will exit our forecast area
and continue to track eastward towards Alabama. This will allow for
a 1019mb sfc high to build across the southeast CONUS. Rain chances
will linger into the evening south of Hwy 84 before dissipating.
Elsewhere, the northern half of the CWA will remain dry with quiet
conditions expected through the night. HREF guidance is hinting at
some fog potential south of I-20 later in the overnight period.
Nighttime temperatures will drop in the low 70s across the area.

Temperatures and dewpoints will gradually increase tomorrow as upper
ridging and the aforementioned sfc high builds across the area
tomorrow. Gulf moisture will start to creep northward on Saturday
and Sunday with some low end pop chances (35-45%) south of I-20.
850mb Temperatures aloft will climb into the low 20s across our
forecast area which will result in afternoon highs reaching in the
upper 90s. A few spots across the Golden Triangle could see sfc
temps in the low 100s. The highest temperatures appear concentrated
for along and north of Hwy 82 where dewpoints will peak in the low
to mid 70s, and a drier airmass will allow for deeper mixing. A Heat
Advisory has been introduce for tomorrow for all of our northeast
Louisiana Parishes and portions of southeast, central, southwest,
south central and west central MS from 10 AM to 7 PM Saturday
evening. The Limited Risk for dangerous heat has been upgraded to an
Elevated Risk for areas where the Heat Advisory is in effect.

Saturday Night through late next week...

Later on Sunday, temperatures and dewpoints will continue to
increase across our forecast area with heat indices between 105F-
110F deg range. A heat advisory will likely be needed for this
timeframe with a possible extension further northward across the
Delta. Heading into the new work week, the sfc high will start to
shift east towards Alabama. This will allow for rain chances to make
a brief return to the area Monday-Wednesday as Gulf moisture creeps
northward across our forecast area. The combination of sfc temps in
the upper 90s, afternoon convection, and dewpoints climbing in the
mid 70s could yield heat indices greater than 110. No changes have
been made to the heat graphic for the Monday-Wednesday timeframe and
Elevated Risk for dangerous heat has been maintained in our HWO
graphic for our entire CWA. Expect further updates to the heat
graphic as we get closer to the new work week. Excessive Heat
Warnings will likely be needed for portions of the area early next
week, especially in the Delta where dewpoints will hold in the mid
to upper 70s. We will continue to carry limited/elevated heat
messaging in our HWO for this weekend and early next week.

By late next week, future guidance hints at strong upper ridging
building over the western CONUS. This will force an upper trough
over the eastern CONUS to dig southward. Some of this cooler, drier
airmass may make it to our far northern areas, however given the
positive tilt orientation of the trough axis, most of the forecast
area will remain under a SW flow regime with some decent rain
chances possible across the area. With the moisture flow from the
Gulf sticking around late next week, heat indices will remain
elevated, especially further south. Given the low forecast
confidence for the heat later in the week, will hold off heat
messaging at this time. /CR/

&&

.AVIATION...
(06Z TAFS)
Issued at 1239 AM CDT Sat Jul 13 2024

VFR conditions will prevail with variable winds with scattered
clouds. There is a chance for an isolated thunderstorm for
HBG/PIB/HEZ. Isolated storms taper off shortly after sunset./SAS/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       96  76  95  76 /  20  10  50  10
Meridian      99  75  99  74 /  20   0  40  10
Vicksburg     96  76  94  75 /  20  10  40  10
Hattiesburg   97  76  96  76 /  40  10  60  10
Natchez       93  75  93  75 /  40  10  50  20
Greenville    96  76  96  75 /   0   0  20  10
Greenwood     98  76  97  75 /  10   0  20  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory from 10 AM this morning to 7 PM CDT this evening
     for MSZ040-041-047>049-053>055-059>066-072>074.

LA...Heat Advisory from 10 AM this morning to 7 PM CDT this evening
     for LAZ007>009-015-016-023>026.

AR...None.
&&

$$

CR/CR/SAS20