607
FXUS64 KJAN 281728
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1228 PM CDT Fri Jun 28 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 923 AM CDT Fri Jun 28 2024

A stalled surface boundary draped across the Pine Belt will serve
as the main area for development of showers and possibly a few
storms this afternoon. Warm temps aloft will result in weak lapse
rates and thus will limit severity. Further north and west,
ridging aloft is building in and will suppress rain and storm
chances in the Delta. This allows temperatures to warm into the
mid to upper 90s, while surface flow remains southwesterly,
holding dewpoints in the mid 70s. Heat advisory is in effect today
until 8PM.

&&

.DISCUSSION...
Issued at 534 AM CDT Fri Jun 28 2024

Today through tonight...

Early this morning, synoptic analysis indicate shortwave over the
Gulf Coast while mean 592-593DM ridge is centered over central to
southwestern TX. Water vapor/RAP imagery & 00Z sounding analysis
indicate shortwave centered over the Gulf Coast while we remain on
under northeasterly flow aloft of the wave rounding underneath the
building ridge. A sfc boundary & deeper moisture, near an inch &
three quarters to near 2 inch PWs are pooling in the Pine Belt to
southeast of the Natchez Trace & progged to persist that way through
the aftn. Light to near calm winds & moist boundary layer have aided
in some fog formation, with HREF & some CAMs persistent in some
patchy dense fog potential. Added a "Limited" fog in HWO graphics
through mid-morning. The best moist convergence this aftn will
remain southeast of the Natchez Trace, while less moist advection &
no rain chances will occur across the Delta. There shouldn`t be much
in the way of thunder as progged Showalters remain positive, but
can`t rule out some isolated potential southeast of the Natchez
Trace. Highs will be near to seasonably warm in the low 90s east to
mid 90s northwest of the Natchez Trace. With high dewpoints in the
75-78F range, heat indices could peak well into the 105-110F range
across the Delta while near 105F elsewhere. Adjusted the HWO graphic
accordingly. Kept the going heat headlines, but expanded the Heat
Advisory into Holmes, Yazoo, Hinds, Copiah, Claiborne, Jefferson,
Franklin & Adams counties. With ridging building in & southerly
return/moist boundary layer, expect seasonably warm lows in the mid-
upper 70s, especially northwest of the Natchez Trace. /DC/

Saturday through Friday...

Hot temperatures and dangerous heat conditions will become more
oppressive across our forecast area as global guidance highlights an
upper-level high amplifying over Texas and gradually building across
the Gulf Coast states into the southeast CONUS. This will bring
oppressive heat and humidity across the area through the weekend
into early next week. As we head into the new work week, global
guidance shows the high pressure flattening, especially in northeast
MS, in response to upper level system off to the northeast. No
changes were made to the "Elevated" heat risk heading into the
weekend. We maintained a "Significant" risk in HWO graphics for
excessive heat Saturday and Sunday, mainly for portions of the
ArkLaMiss Delta in Chicot in AR southward to West-East Carroll and
Madison in LA, to along and northwest of a line from Warren, Hinds
northeast into Leflore to Grenada counties. These areas have seen
persistent excessive heat, with less rain and storm chances Saturday
before scattered to numerous coverage late weekend into early next
week. However, excessive heat could be reached prior to convective
initiation after midday, so kept it going through the weekend. Heat
related advisories and excessive heat warnings will likely be needed
as we get closer. Additional dangerous heat is likely into early
next week, but the focus turns more south of Hwy 82 and more along
the I-20 corridor and southward, where heat headlines could be
needed as we get closer. The HWO graphics were broken down to hit
the buildup in heat from Friday through the weekend as one graphic,
with less significant but still dangerous heat slightly further
south in a separate graphic for Monday. Additional dangerous to
significant heat stress is likely into middle of next week, but will
hold off messaging for now.

A frontal boundary is expected to push towards the southeast,
increasing shower/thunderstorm potential Sunday afternoon and
Monday. The potential for severe weather is low around this
timeframe, but there are continued signals in CSU machine learning
probs for marginally severe storms Sunday into Monday. As anomalous
high pressure builds across the region, coverage of rain and storm
chances will become confined along and southeast of the Natchez
Trace corridor and on the periphery of the ridge aloft. The pattern
may break down late week, but confidence in needed relief from
dangerous to significant heat stress remains low at this point.
/CR/DC/

&&

.AVIATION...
(18Z TAFS)
Issued at 1223 PM CDT Fri Jun 28 2024

Clouds have mostly scattered out and some isolated showers are
beginning to up in the vicinity of eastern sites, GTR, MEI, HBG,
and PIB. These should continue this afternoon and taper off this
evening, shortly after sunset. VFR conditions prevail through the
period with winds out of the southwest around 5 to 10 kts./SAS/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       75  93  76  93 /  10  40  10  60
Meridian      74  93  74  95 /  20  60  20  80
Vicksburg     77  95  76  94 /  10  20  10  40
Hattiesburg   76  93  76  95 /  30  70  20  70
Natchez       75  93  75  93 /  20  40  10  40
Greenville    78  96  79  94 /   0  10   0  50
Greenwood     76  94  77  94 /   0  20  10  60

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory until 8 PM CDT this evening for MSZ018-019-025-
     034>036-040>042-047-048-053-054-059>061.

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

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

&&

$$

DC/CR/SAS20