619
FXUS64 KJAN 151000
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
500 AM CDT Thu Aug 15 2024

...New DISCUSSION...

.DISCUSSION...
Issued at 500 AM CDT Thu Aug 15 2024

Through the End of This Week:

Heat and Humidity. Hard to say it is good for much, but in this case
the increased humidity is at least enough to bring rain chances to
our forecast area. That`s a positive for sure. The disturbance which
moved south across the area yesterday is still in the region and may
provide some enhanced rain chances farther south toward the Gulf
Coast this afternoon and evening. A pool of 2.0+ PW air will be
located south of Interstate 20 today, but even the drier air farther
north should still have enough moisture (PW > 1.6-1.7) today to
support some isolated showers or storms. The influence of the ridge
aloft will be felt as temperatures climb into the mid and upper 90s
before most shower or storm activity gets going. Forecast soundings
show possibility of greater than 2000-3000 J/kg of SBCAPE and around
1000 J/kg of DCAPE, so some strong storms with gusty winds cannot be
ruled out. Given the observed heat index values yesterday and the
forecast for today/tomorrow/Saturday, felt it was reasonable to
upgrade the western and southern portions of the forecast area to an
Excessive Heat Warning and advertise "Extreme" dangerous heat
impacts on the local HWO graphics to account for multi-day threat of
110+ heat indices especially west of Interstate 55 and down into the
Pine Belt. Pop up showers or storms may provide some localized
relief, but it appears we are in for a multi-day heat wave with the
ridge centered to our west bringing the heat and surface ridging
centered to our east keeping the humidity in place.

A low pressure system pivoting over the Great Lakes will nudge a
cold front toward the Mid-South/Interstate 40 corridor by Saturday
afternoon, with increased jet stream winds accompanying the front
southward. The increased flow and wind shear is expected to support
severe storm development in the vicinity of the front Friday into
Saturday, with storms then possibly moving southward into better
instability either day. There is a Marginal Risk for organized
severe storms Friday afternoon into evening for far northern parts
of our area, and then across more of the CWA by Saturday afternoon
and evening as the front moves into the area.

Sunday into Next Week:

Model guidance shows the front to get a better push southward toward
the Gulf Coast Sunday into Monday. Main differences behind the front
will be drier air and slightly cooler mornings (upper 60s vs mid
70s). Afternoons will feel cooler too, though mainly because of the
lost humidity. /NF/

&&

.AVIATION...
(06Z TAFS)
Issued at 105 AM CDT Thu Aug 15 2024

VFR conditions will prevail across the entire forecast area
through 12Z Thursday with a some scattered SHRA/TSRA possible
across the Pine Belt. Rain chances should start to increase
across much of the area later this afternoon starting around 18Z
Thursday with the best chance south of I-20. Rain chances will
start to decrease starting around 0Z Friday with VFR ceilings and
light winds prevailing. /CR/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       97  76  97  77 /  30  20  50  10
Meridian      98  75  97  74 /  30  10  50  10
Vicksburg     98  77  97  77 /  30  20  30  10
Hattiesburg   97  76  96  75 /  40  20  50  10
Natchez       98  76  96  75 /  40  20  30  10
Greenville    98  77  99  77 /  20  10  20  10
Greenwood     98  77  99  77 /  20  10  30  20

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Excessive Heat Warning from 10 AM this morning to 8 PM CDT this
     evening for MSZ018-019-025>027-034>036-040>043-047>049-
     053>055-059>064-072>074.

     Heat Advisory from 10 AM this morning to 8 PM CDT this evening
     for MSZ028>033-037>039-044>046-050>052-056>058-065-066.

LA...Excessive Heat Warning from 10 AM this morning to 8 PM CDT this
     evening for LAZ007>009-015-016-023>026.

AR...Excessive Heat Warning from 10 AM this morning to 8 PM CDT this
     evening for ARZ074-075.

&&

$$

NF/CR