170
FXUS64 KJAN 060559
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1259 AM CDT Sat Jul 6 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 956 PM CDT Fri Jul 5 2024

At mid evening local radars showed scattered thunderstorms
gradually weakening over the southwest portions of our CWA. With
the loss of daytime heating much of the convective potential will
end but with the weak frontal boundary dropping through the CWA,
there will be a low chance of redevelopment through the remainder
of the night generally south of Highway 82. Patchy early morning
fog will be possible in the areas that received significant
rainfall but dense fog is not anticipated. /22/

&&

.DISCUSSION...
Issued at 259 PM CDT Fri Jul 5 2024

Rest of this evening through Saturday...

Afternoon analysis indicates frontal zone sinking southward across
the region, leading to widespread showers & storm development across
the Natchez Trace corridor & southward. This is in response to a
highly destabilized & moist tropical environment, favoring tropical-
like downpours & QPF maxima of >3-4" common, with locally higher
amounts possible. The ongoing "Limited" for flash flooding remains
valid into this evening around 10PM or so. There have been a few
cores that have sparked up there or oriented orthogonal to light
west-northwest low-level shear, so some strong-isolated severe
storms remain possible through the evening. Expect convection to
wind down slowly overnight, with a majority of thunder potential
gone around 9-10PM & some showers persisting through around midnight.
HRRR indicates some redevelopment in the wake of this ongoing line,
but current radar trends seem to be focused further northwest. There
could still be some isolated potential in the wake, but likely not
as vigorous, unless moving through untapped thermodynamic profiles.
With clouds & deep moisture, near to seasonably warm lows in the
low-mid 70s are expected.

As the shortwave trough swings across the northeast & another into
the northern Plains, the mid-level ridge will flatten & build more
into the northeast Gulf. This will also be moderated by Tropical
Storm Beryl, which should gradually become more organized into the
weekend across the Bay of Campeche into the southwestern Gulf of
Mexico on the trek near International Border & south Texas coast.
This should keep a deep, anomalous & near climatological maximum
moisture profiles of PWs of 2.25-2.5 inches. Expect rain chances to
slowly begin to creep up before midday, becoming more scattered near
midday & widespread south of I-20 into Saturday aftn. Can`t rule out
some stronger storms again into the aftn-evening hours. HREF prob
match mean of >3" are lower than today but remain possible in the
Hwy 84 to I-59 corridors. Holding off any introduction for flash
flooding in the HWO graphics at this point. Even with more
seasonable highs in the upper 80s to low 90s, sfc dewpoints pooling
in the 77-80 degree range will again favor some potential increased
heat stress for areas along & south of I-20 & east of the MS River.
Added a "Limited" heat in the HWO graphics, with heat indices
peaking near or in excess of 105F briefly. Held off on a heat
advisory for now as convection will modulate the potential, but will
need to be reevaluated. /DC/

Saturday night and Sunday: Though a surface front will sag briefly
into the northern portion of the area this weekend, it appears any
relief in the form of lower dewpoints will mainly be confined to the
Hwy 82 corridor and northward. A moist airmass with dewpoints in the
mid to upper 70s and PW of 2-2.5 inches will remain entrenched
across the remainder of the area. Showers and thunderstorms ongoing
from the daytime Saturday will linger into the early evening across
mainly south MS and central LA before diminishing overnight. Then
another round of showers and storms is likely with daytime heating
on Sunday. Ultimately, the front will begin to retreat northward by
the daytime Sunday. Though daytime temps Sunday may be limited by
increasing coverage of clouds and convection, there may still be
enough opportunity across southern portions of the area for early
heating to result in heat indices rising to near critical
thresholds. For this reason, we will maintain the limited heat
stress hazard graphic into Sunday.

Monday through next Friday: As an upper level trough persists over
the central part of the country and a more subtle ridge axis extends
from the northern Gulf to along the East Coast, southwesterly to
westerly upper flow will continue over our area for much of next
week. This pattern will help to maintain a steady feed of deep layer
moisture across our area, which will keep at least scattered diurnal
convection around each day. We continue to monitor what will happen
with the remnants of Beryl, as this may help to enhance rain chances
particularly Tuesday and Wednesday. Toward the end of the week, the
eastern ridge may begin to wield greater influence, which could
bring warmer and drier conditions.

Of course, we must talk about those pesky heat indices. With higher
rain chances especially earlier in the week, uncertainty is high
with respect to peak temps and heat indices each day. However, at
least limited heat stress issues may persist especially over the
southern half of the area next week. /DL/

&&

.AVIATION...
(06Z TAFS)
Issued at 1255 AM CDT Sat Jul 6 2024

A considerable amount of IFR/LIFR category stratus is expected for
mainly southeast portions of the forecast area through early to
mid morning, then expect quickly improving conditions during the
late morning. Scattered SHRA/TS will be most prominent during the
afternoon to early evening for the southern half of the area.
Otherwise, VFR conditions and light surface wind will prevail. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       74  90  74  92 /  10  50  20  50
Meridian      73  92  73  94 /  20  60  30  60
Vicksburg     74  89  75  91 /  10  40  20  40
Hattiesburg   76  94  76  94 /  30  70  20  60
Natchez       74  90  75  91 /  20  50  20  50
Greenville    73  90  75  91 /   0  30  20  50
Greenwood     74  91  75  93 /   0  30  10  50

&&

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

&&

$$

22/DC/DL/EC