646
FXUS64 KJAN 281155
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
655 AM CDT Fri Jun 28 2024

...New AVIATION...

.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...
(12Z TAFS)
Issued at 655 AM CDT Fri Jun 28 2024

High moisture in the boundary layer, combined with residual sfc
boundary around, has led to some development of MVFR-LIFR
ceilings in spots & MVFR-IFR vsby down from low stratus & patchy
to locally patchy dense fog. This is mostly the case in central,
north-central to eastern TAF sites. Expect any restrictions to
improve after daybreak, with some scattered SHRA & iso VCTS in
east-southeast TAF sites, mainly near MEI, HBG & PIB. This will
persist through early evening, ending around 29/00Z. Light
southerly winds, at times variable & generally under 10mph, are
expected through the TAF period. Some MVFR ceilings &/or vsby are
psbl in east-southeast TAF sites late tonight through daybreak
Saturday. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       92  75  93  76 /  30  10  40  10
Meridian      92  74  93  74 /  60  20  50  20
Vicksburg     94  77  95  76 /  10   0  20  10
Hattiesburg   94  76  93  76 /  70  20  70  20
Natchez       93  75  93  75 /  20  10  30  10
Greenville    94  78  96  79 /   0   0  10  10
Greenwood     92  76  94  77 /  10   0  20  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory from 10 AM this morning to 8 PM CDT this evening
     for MSZ018-019-025-034>036-040>042-047-048-053-054-059>061.

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

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

&&

$$

DC/CR