098
FXUS64 KJAN 130250
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
950 PM CDT Fri Jul 12 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 949 PM CDT Fri Jul 12 2024

Rest of tonight...

Regional radars indicate convection is mostly winding down across
the region. Evening water vapor/RAP analysis indicate the region
trapped in between the Atlantic subtropical ridge & 598DM ridge
parked over the Four Corners/Intermountain West. Sfc high is
parked across the Gulf Coast region as well. This synoptic
pattern is aiding in moisture advecting to the north, with deep
moisture climbing from less than an inch & a quarter yesterday
evening to nearly an inch & three quarter PWs this evening. With
boundary layer moisture on the increase, dewpoints will hang up in
the low 70s south of I-20 while upper 60s to the north. Some
broad isentropic moist ascent will help some development of low-
mid level cloudiness overnight. Lows will be seasonable in the low
70s, with the coolest areas in the northeast quarter of the
region. Updates are out. /DC/

&&

.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...
(00Z TAFS)
Issued at 648 PM CDT Fri Jul 12 2024

SCT-BKN cumulus field remains in the VFR range & will thin just
after 13/00-01Z Saturday. Slow-moving SHRA & TSRA remain possible
at southeast TAF sites south of I-20, near PIB & HBG, through
13/01Z Saturday. Some patchy fog/BR can`t be ruled out in southern
TAF sites but confidence remains too low for any flight
restrictive vsby to introduce in the 00Z TAF cycle. Low probs of
light SHRA & isolated TSRA are again psbl Saturday at southern
sites of HEZ, HBG & PIB, mainly late Saturday aftn between
13/19-23Z. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       73  96  76  95 /   0  20  10  50
Meridian      73  99  75  99 /   0  20   0  40
Vicksburg     73  96  76  94 /   0  20  10  40
Hattiesburg   75  97  76  96 /  20  40  10  60
Natchez       73  93  75  93 /  10  40  10  50
Greenville    73  96  76  96 /   0   0   0  20
Greenwood     73  98  76  97 /   0  10   0  20

&&

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

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

AR...None.
&&

$$

DC/CR/DC