522
FXUS64 KJAN 170636 AAC
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
136 AM CDT Sat Aug 17 2024

...New MESOSCALE UPDATE, AVIATION...

.MESOSCALE UPDATE...
Issued at 127 AM CDT Sat Aug 17 2024

At the current hour, radar and satellite imagery trends indicate
a complex of storms moving southeast across Arkansas are in the
process of weakening. Reflectivity cores have been outpaced by the
outflow boundary racing southeastward, and IR satellite imagery
show warming cloud tops with lead part of this system. It can`t be
ruled out that any additional showers or storms would develop
from the outflow, but it would appear that MLCIN is strong enough
to dampen new convection at this time. METAR observations from
central Arkansas have reported wind gusts of around 40 mph with
the outflow boundary, so even if storms stay northwest of our ear
through the early morning, a brief period of strong wind gusts
may move into the ArkLaMiss Delta region over the next hour or so.
If the storms continue to weaken, even this outflow should
continue to lose its punch. Did introduce a slight chance for
showers or storms to far northern parts of the CWA through 12Z in
case. /NF/

&&

.DISCUSSION...
Issued at 216 PM CDT Fri Aug 16 2024

Tonight through late next week...

Dangerous heat remains the primary concern in the near term as our
area remains on the eastern periphery of an upper ridge centered
over Texas. With low level moisture holding steady, temperatures
should only drop to the mid to upper 70s tonight. Therefore, will
maintain heat headlines overnight.

Temperatures are unlikely to change much tomorrow with mainly upper
90s and a few 100s possible. Dewpoints should hold in the mid to
upper 70s, resulting in heat indices in the 105 to 112 range across
the area. Excessive heat warning will continue tomorrow for much of
the area, and a heat advisory will continue in the east.
Additionally, these hot and humid conditions, along with increased
flow and favorable shear vector orientation could support isolated
to scattered thunderstorms tomorrow afternoon with damaging wind
gusts the primary hazard. There is some uncertainty however
regarding the potential for remnant outflow to disrupt the
environment and guidance has trended lower with those chances.
Should the environment remain relatively untapped, favorable
convective parameters should support at least a marginal severe
risk. Rainfall totals look to be around quarter to half inch, and
it should be spotty, with widespread soaking rain unlikely.

Heat is likely to continue into Sunday. Have extended the heat
graphic in HWO to capture this. Moisture pooling ahead of the
advancing cold front should hold dewpoints in the mid to upper 70s
for another day, temperatures warm into the upper 90s and low 100s.
Heat indices once again peak in the 105 to 112 range. Timing of the
front though does introduce a big of uncertainty that could impact
heat risk on Sunday, so confidence isn`t quite high enough at this
time to pick a definitive area for heat headlines. Showers and
storms are possible Sunday too, however a lot is dependent on
Saturday and guidance has trended down on chances for Sunday as
well.

By Sunday night, an upper trough will drive the cold front south,
with dry air and seasonal temps in its wake. Next week should be
fairly dry and seasonal with temperatures mainly in the low 90s.
Troughing to the east and ridging to the west should maintain NW
flow through much of next week, keeping dry conditions. By the end
of next week, moisture begins to return as low level flow turns
southerly. This should reintroduce low rain chances in the south.
Some guidance tries to develop a low to our southwest by next
weekend, in which case, rain chances should generally increase./SAS/

&&

.AVIATION...
(06Z TAFS)
Issued at 127 AM CDT Sat Aug 17 2024

VFR conditions should prevail at the TAF sites through the period,
however the chance for scattered SHRA or TSRA mainly between 19Z
today to 01Z Sunday does bring the possibility of variable
ceilings, gusty winds, and reduced visibility near any stronger
storms. Current confidence in impacts to any particular TAF site
from thunder were too low to mention in the TAFs at this time.
/NF/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       76 101  75  94 /  20  20  40  10
Meridian      74 101  72  94 /  20  20  50  10
Vicksburg     76 101  74  93 /  20  20  40  10
Hattiesburg   77 101  75  97 /  20  10  50  20
Natchez       76 100  75  93 /  20  10  30  10
Greenville    76 100  72  92 /  20  20  30  10
Greenwood     75  99  72  92 /  20  20  30  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Excessive Heat Warning until 8 PM CDT this evening for MSZ018-
     019-025>029-032-034>037-040>044-047>050-053>057-059>066-
     072>074.

     Heat Advisory until 8 PM CDT this evening for MSZ030-031-033-038-
     039-045-046-051-052-058.

LA...Excessive Heat Warning until 8 PM CDT this evening for
     LAZ007>009-015-016-023>026.

AR...Excessive Heat Warning until 8 PM CDT this evening for ARZ074-
     075.

&&

$$

SAS20/NF