678
FXUS64 KJAN 241816 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
116 PM CDT Mon Jun 24 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 1015 AM CDT Mon Jun 24 2024

Local radars had a band of light showers just south of Interstate
20 and east of Interstate 55 at mid morning. This band of showers
was along a very weak cold front that will continue to sag south
through the southern portions of our CWA this afternoon. A surface
high to the northeast will help push the cold front south. This
cold front and surface high will only result in slightly drier
air over the northeast. Otherwise, the afternoon temperatures in
the mid to upper 90s will combine with the high humidity to result
in high heat index values and the Heat Advisory will remain in
effect this afternoon. /22/

&&

.DISCUSSION...
Issued at 316 AM CDT Mon Jun 24 2024

Today and Tonight...High pressure aloft wedged into the region from
the west, has weakened enough over the forecast area to allow a weak
frontal boundary to sink south into the CWA.  This boundary will
primarily be responsible for bringing an increase in cloud cover to
the area today.  However, it`ll also bring with it a chance for
isolated to scattered showers, and isolated thunderstorms across
mainly central and southern portions of the CWA through this
afternoon as it drops further south through the forecast area.

Winds will become northerly around 5 mph in the wake of the
boundary. Unfortunately for us, no change in airmass will exist
across the area.  The boundary will eventually stall across southern
portions of the CWA tonight, where it`ll gradually washout.  Any
convection that`s ongoing during the afternoon will begin to wane
during the late afternoon and early evening hours as daytime heating
is lost.  Mostly clear skies will exist tonight, with lows only
following into the 70s.

Once again, the main concern during the period will be the increased
heat stress across the region this afternoon. Dew points will range
from the upper 60s to middle 70s this afternoon.  This, coupled with
high temperatures ranging from the mid 90s to around 100, will
generally yield afternoon heat index values between 105-110 across
nearly the entire forecast area.  As a result, the "Heat Advisory"
has been expanded to cover the entire forecast area through 8 PM
this evening. /19/

Tuesday...Oppressive heat will continue into Tuesday as mid level
ridging hangs on just enough to limit convective coverage to
mainly isolated diurnal activity for one more day. Northeast/east
MS will fair best in terms of humidity due to the nearby presence
of a weak front that will allow a somewhat drier airmass to tease
the area. Unfortunately, this may help temps to soar to around 100
in those areas. Highest heat indices will be along and west of
I-55, where dewpoints are more likely to remain in the mid 70s
through the day. Accordingly, we have extended the Heat Advisory
to include the daytime Tuesday. Even where dewpoints may be more
marginal from Meridian up to the Golden Triangle area, temps will
be high enough that it will still be very possible to reach
advisory thresholds.

Wednesday and Thursday...With the upper ridge temporarily
retreating, NW flow aloft will bring a shortwave across the area
Wednesday. Given the moist airmass in place ahead of this feature,
precip coverage is expected to be greater. This is also a window
when there would be some potential for an upstream convective
complex to move into the area, but it`s a bit too early to clearly
anticipate these mesoscale details. Lingering shortwave troughing
along the Gulf Coast will provide an opportunity for higher rain
chances again on Thursday, but focused more over the southern half
of the area. Meanwhile, upper ridging will begin to build again
into the northern half of the area. Overall, clouds and rain will
be more likely to limit daytime temperatures Wednesday and
Thursday than on previous days, but in any areas where clouds/rain
are limited, heat stress may continue to be an issue with heat
indices still potentially reaching dangerous thresholds.

Friday through Sunday: The upper ridge will continue to build over
the area, with temperatures trending back upward. However, the
seasonably moist airmass will remain, fostering mainly diurnal
convection each day. Greatest coverage will be focused over the
eastern half of our area, which will be farthest from the middle of
the ridge. Heat stress concerns will continue to be in the picture
outside of brief relief from any rain. /DL/

&&

.AVIATION...
(18Z TAFS)
Issued at 112 PM CDT Mon Jun 24 2024

Isolated -SHRA wl come in vcty of MEI and the southern TAF sites
until after 01Z. Otherwise, VFR conditions and a light wind wl
prevail through the TAF period. /22/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       96  75  97  77 /  20   0  20  10
Meridian      98  73 100  74 /  20   0  20  10
Vicksburg     96  76  97  77 /  10   0  20  10
Hattiesburg   96  76  98  76 /  40  20  40  10
Natchez       94  74  95  75 /  20  10  30  10
Greenville    99  77 100  77 /   0   0  10  20
Greenwood     98  76 100  77 /  10  10  20  20

&&

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

     Heat Advisory from 10 AM to 8 PM CDT Tuesday for MSZ018-019-
     025>066-072>074.

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

     Heat Advisory from 10 AM to 8 PM CDT Tuesday for LAZ007>009-015-
     016-023>026.

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

     Heat Advisory from 10 AM to 8 PM CDT Tuesday for ARZ074-075.

&&

$$

19/DL/22