-- Discussion containing changed information from previous version are highlighted. --
583
FXUS64 KJAN 301450
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
950 AM CDT Sun Jun 30 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
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Issued at 939 AM CDT Sun Jun 30 2024

Northerly flow has allowed for less ascent and cloudcover this
morning compared to 24 hours ago, and so any precip has held off.
This should allow temperatures to warm into the low to mid 90s,
assuming convection holds off til afternoon, which most CAM
guidance does, with most initiating by mid afternoon. With
dewpoints holding in the upper 70s with spots of 80, will continue
to carry heat headlines and messaging. Weak mid level lapse rates
should serve to limit severity of storms, but as always
conditions will be monitored through mesoanalysis./SAS/
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&&

.DISCUSSION...
Issued at 404 AM CDT Sun Jun 30 2024

Today and Tonight:

Once again, dangerous heat will be the main concern for today as
early morning global guidance continues to highlight upper ridging
across much of the southeast CONUS. Afternoon highs will peak in the
mid to upper 90s areawide with dewpoints climbing in the upper 70s.
Several areas across the Delta could see dewpoints in the 80s. This
combination will yield heat indices in the 105-115 deg range across
our forecast area. For this reason, an excessive heat warning
remains in effect until 8 pm this evening, including the Delta, our
southeast Arkansas counties, and all of our northeast Louisiana
parishes. Elsewhere, a heat advisory remains in effect mainly for
areas along and east of the I-55 corridor. No changes have been made
to the heat graphic for today and a "Significant" risk has been
maintained where the excessive heat warning remains in effect. Hot
and muggy conditions will persist today as early morning HRRR
guidance holds off convection until later this afternoon, with the
best rain chances across the Pine Belt.

Global guidance shows a high pressure system moving east across the
Ohio River Valley later this evening. At the same time, a weak cold
front, located on the southern periphery of the aforementioned sfc
high, will push south into the northern portions of our forecast
area. Rain chances will still be possible along and south of the
cold front later in the evening before diminishing heading into the
overnight period. Expect nighttime temperatures to drop in the low
to mid 70s areawide. /CR/

Monday through Saturday:

Drier post-frontal air mass on Monday will be enough to keep rain
chances mostly out of our forecast area. By the late afternoon, PWAT
values should be 1.5 inches or less north of the Highway 84
corridor. The ridge pivoting overhead will still keep temperatures
warm, so areas behind the front are looking at highs in the low 90s
(normal for early July). In the frontal zone closer to the Gulf
Coast, afternoon highs and increased humidity will result in heat
index values in the 105 to 110 degree range. A Heat Advisory is
likely to be issued for southern parts of the forecast area, but
will let the Excessive Heat Warning today play out before issuing a
follow-up product for tomorrow.

As the front washes out, temps should quickly rebound for the rest
of the week. Daily rain chances will be focused in the afternoon
with peak heating and mainly in the south and southeast with
possible sea breeze activity and better moisture availability. Flow
trajectories around the high will bring drier air generally from the
east through most of the period. Friday into the weekend, the ridge
shifting farther east will allow for troughing to more influence the
central and southern US. Another cold front moving into the region
will likely bring another focus for rain during the weekend. We will
also keep an eye toward the Tropics as several areas of interest in
the Atlantic are monitored by the National Hurricane Center and as
Hurricane Beryl moves westward toward the Caribbean. /NF/

&&

.AVIATION...
(12Z TAFS)
Issued at 618 AM CDT Sun Jun 30 2024

VFR ceilings will occur across central MS to start off the TAF
period. Weather conditions will remain quiet through 17Z with mid to
high clouds expected. By 18Z Sunday afternoon, convection will start
to develop along the Hwy 84 corridor around this timeframe before
becoming widespread around 19Z as the seabreeze slowly drifts north.
Added VCTS and SHRA to most zones with a short period of MVFR to
possible IFR ceilings for PIB, HBG, HKS, JAN from mid to late
afternoon. Rain activity will continue into the evening. By 06Z
Monday rain chances will come to an end with VFR ceilings prevailing
across all TAF sites. VFR ceilings will occur through 07Z Monday. By
08Z Monday, ceilings will drop down to MVFR to potential IFR
conditions as cloud cover increases across central MS. Ceilings will
remain in MVFR status through 15Z Monday. By 16Z Monday, ceilings
will start to improve to VFR status. /CR/

&&

.PRELIMINARY POINT TEMPS/POPS...
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Jackson       95  76  93  70 /  50  40  10   0
Meridian      96  73  94  68 /  60  40  10   0
Vicksburg     95  76  93  70 /  50  30  10   0
Hattiesburg   95  77  96  74 /  60  30  20   0
Natchez       95  76  93  72 /  40  30  20   0
Greenville    97  75  91  68 /  50  40   0   0
Greenwood     95  73  92  68 /  50  40   0   0
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&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Excessive Heat Warning until 8 PM CDT this evening for MSZ018-
     019-025>027-034>036-040>042-047-053-059-060.

     Heat Advisory until 8 PM CDT this evening for MSZ028>033-037>039-
     043>046-048>052-054>058-061>066-072>074.

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.

&&

$$

CR/NF/CR