459
FXUS64 KJAN 121459
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
959 AM CDT Thu Jun 12 2025

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 945 AM CDT Thu Jun 12 2025

A seasonally moist airmass (observed 1.7 inch PWAT on 12z JAN
sounding) reinforced by southerly flow on the eastern flank of a
cutoff upper low will be supportive of isolated scattered showers
and thunderstorms this afternoon. Notable cirrus blow off from a
festering complex over eastern Texas could limit coverage earlier
on, but should steadily increase later this afternoon and evening
as the low gradually shifts east. Isolated strong to severe storms
are possible with a main threat for wind and possibly a brief
tornado. The deep tropical moisture supportive of efficient rain
rates means heavy downpours are certainly possible in any deeper
cores that develop./SAS/

&&

.DISCUSSION...
Issued at 320 AM CDT Thu Jun 12 2025

Through next Wednesday night...

Today and Tonight: Synoptic pattern consists of upper level flow
cutting off over the Red River Valley, with persistent, moist
southerly return flow and deep tropical moisture (+2 inches)
situated across the Gulf Coast region. Scattered to numerous rain
and storm coverage is anticipated this aftn to evening (55-85%).
Upper level jet dynamics and southwesterly low-level jet will be
increased across the ArkLaTex region by the aftn hours. Lapse
rates won`t be too impressive, but there is support from
convective allowing models (CAMs) in HREF to support continued
mention of isolated strong to severe storms. Kept mention of the
"Marginal" for along and northwest of the Natchez Trace corridor,
for mainly wind and a brief tornado can`t be ruled out. Timing
will be late aftn to evening (3-10PM). Localized heavy downpours
of >2 inches are possible but mesoscale driven and too difficult
to nail down an area of concern for heavy rain. Added mention of
localized heavy downpours in the HWO severe graphic. Rain and
storm chances wind down into the early evening across the heart of
the region, but isolated to scattered coverage (15-55%) will
continue in the Delta region overnight. Sensible weather will
consist of seasonable highs (86-92F) and seasonably warm lows,
some 3-8F above (70-74F).

Friday through next Wednesday night: Cutoff low to the west will
gradually lift north and somewhat phase with the synoptic jet
situated well off to the north southern Canada, Hudson Bay,
Newfoundland and northern Atlantic. This will aid in continued
numerous to widespread rain and storm coverage persisting Friday
into the weekend but shifting focus further eastward. Low level flow
will lighten and become more westerly. Highs will be seasonable
through the weekend (86- 93F), with seasonably warm lows, some
3-8F above (70-74F). High humidity will lead to increasing heat
stress into late weekend. This is only exacerbated by recent and
continued wet pattern/increased soil moisture. High boundary layer
moisture and dewpoints ranging from 73-78F daily support aftn
heat indices exceeding 100F and increased heat stress. This
typical summertime warm and humid pattern, outside of the
continued excessive rain and storm coverage, will gradually worsen
by late weekend. Holding off heat stress mention in HWO graphics
for now.

As the upper level low lifts northeast into the TN Valley to
Appalachians, westerly low level flow will support some continued
moist advection and deep moisture around 2 inches. Scattered to
numerous rain and storm coverage continue, with another shortwave
trough progged axis progged to swing across the Mid South to Gulf
Coast states into early to mid next week. This increased ascent,
combined with deep tropical moisture, support continued rainy
pattern. Muggy conditions worsen as highs moderate to seasonably
warm, some 2-5F above (88-92F Monday to 90-95F both Tuesday to
Wednesday) while lows remain seasonably warm, some 3-9F above (72-
77F Monday and Tuesday while the warmest on Wednesday morning).
Combined with an uptick in boundary layer moisture, heat stress
will worsen through midweek. Make sure to stay hydrated, wear
comfortable and cool clothing and check on family, neighbors and
pets who may need cool places to stay during hot afternoons and
muggy nights. /DC/

&&

.AVIATION...
(12Z TAFS)
Issued at 649 AM CDT Thu Jun 12 2025

Most TAF sites are VFR this morning, but occasional IFR ceilings
are occuring at JAN/HKS. Expect Mostly VFR conditions to prevail
through much of the period, but there could be some patchy IFR/MVFR
ceilings until 14-15Z. Showers/storms will develop once again
this afternoon and this will bring scattered MVFR/IFR conditions
to sites./15/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       91  73  89  73 /  50  30  80  30
Meridian      91  72  90  71 /  40  30  80  30
Vicksburg     89  73  89  73 /  60  40  80  30
Hattiesburg   92  74  91  74 /  30  20  90  20
Natchez       88  73  88  73 /  70  40  80  20
Greenville    88  71  85  72 /  70  60  80  50
Greenwood     90  73  88  72 /  50  50  90  50

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

$$

DC/DC/15