780
FXUS64 KJAN 240522
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1222 AM CDT Mon Jun 24 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 1017 PM CDT Sun Jun 23 2024

Forecast thinking remains generally the same for the overnight
hours with a few showers potentially developing as a weak boundary
pushes southward across the area. Relatively warm air aloft (-1.7
deg C at KJAN on 00z raob) will inhibit potential for deep
convection. /EC/

&&

.DISCUSSION...
Issued at 221 PM CDT Sun Jun 23 2024

Tonight and Tomorrow...

Global guidance shows the mid/upper level high drifting further west
towards the Carolinas. With the high shifting westward, this will
allow for a weak frontal boundary to sink into our forecast area
heading into the overnight period. Because of this, areas along the
far northern portions of our CWA could see some isolated showers by
early Monday morning. With increasing clouds overnight, nighttime
temperatures will fall into the mid 70s to around 80. Heading into
Monday, moisture will continue to increase across the area thanks to
southerly flow aloft. As the aforementioned frontal boundary
continues to sag further south across central MS, global guidance is
highlighting a weak sfc front that will slop into northeast MS,
stalling through the day. Isolated showers will be possible heading
into Monday afternoon with slightly higher rain chances (around 30%)
south of the I-20 corridor thanks to sufficient daytime heating.

With the anticipated moisture heading into Monday afternoon,
dewpoints will climb into the upper 70s areawide as afternoon highs
peak into the upper 90s. This level of heat and humidity will result
in afternoon heat indices between 105-112 degrees. As a result, a
"Heat Advisory" has been issue for the entire CWA for this
timeframe. /CR/

Monday night through Saturday night: Heat and humidity still look to
be the main concerns through the period with Tuesday expected to be
the most oppressive day.

Come Monday evening our CWA will be on the eastern periphery of a
large 592dam high while a stalled and nearly diffuse cold front will
be just south of our CWA. A 1014mb high will be centered just
northeast of our CWA The surface high will continue shifting east
Monday night and Tuesday allowing for a light return flow back
across our CWA. This will allow low level moisture increase while
afternoon highs top out around 100F along our Highway 82 zones and
upper 90s elsewhere. The hot temperatures will combine with the high
humidity to result in peak heat index values between 105F and 110F
and a Heat Advisory will likely be extended for the whole CWA
Tuesday.

By Wednesday morning the large mid level high will have become
centered just south of the Four Corners region. A shortwave trough
topping the ridge will spill into our region during the day and lead
to a greater coverage of convection and perhaps an earlier start.
Greatest coverage is expected over the eastern half of our CWA and
the cloud cover associated with the convection is expected to help
hold temperatures a few degrees cooler than on Tuesday. This will
result in lower peak heat index values. The shortwave trough is
still expected to be dropping south along the Mississippi/Alabama
stateline Wednesday night helping to maintain rain chances over the
southeast half of the CWA until tapering off from the northwest
Thursday afternoon and early evening. Friday the mid level high is
progged to build east back across our region. This will lead to
warmer temperatures and raise the concern of heat stress again. Rain
chances Friday and Saturday afternoons will be limited to our
southern zones. /22/

&&

.AVIATION...
(06Z TAFS)
Issued at 1220 AM CDT Mon Jun 24 2024

VFR flight categories will prevail at area TAF sites over the
next 24 hours. A weak frontal boundary will sink south through the
region overnight into this morning. This will result in some
scattered clouds developing across the area through the forecast
period, with some isolated convection possible as well through the
forecast period, especially this afternoon across southern
portions of the area. Calm to light southerly winds from the
south overnight, will gradually give way to winds becoming more
northerly around 5 knots in the wake of this boundary. /19/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       96  75  97  76 /  30   0  30  10
Meridian      98  74 100  74 /  20   0  30  20
Vicksburg     96  76  97  76 /  10   0  20  10
Hattiesburg   96  76  99  76 /  40  10  50  10
Natchez       94  75  96  75 /  30  10  30  10
Greenville    99  78 100  77 /   0   0  10  10
Greenwood     98  76 100  76 /  10   0  10  20

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory from noon today to 8 PM CDT this evening for
     MSZ018-019-025>066-072>074.

LA...Heat Advisory from noon today to 8 PM CDT this evening for
     LAZ007>009-015-016-023>026.

AR...Heat Advisory from noon today to 8 PM CDT this evening for
     ARZ074-075.

&&

$$

19