582
FXUS64 KJAN 180618 AAB
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
118 AM CDT Sat May 18 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 938 PM CDT Fri May 17 2024

Mid evening surface analysis had a stalled frontal boundary just
south of our southeast most zones. Regional radars only had a few
light returns across our southern zones. This convection was
occuring downstream of an approaching shortwave trough as seen on
mid evening satellite imagery. Regional radars showed some more
vigorous convection along the stalled boundary and just off the
Texas and southwest Louisiana coasts. As the shortwave continues
to approach our western zones by morning, additional convection is
expected to develop and move along the boundary. Some models move
the boundary to the north by morning allowing some of the
convection to track across our southeast. Isolated severe storms
capable of damaging wind gusts and hail to quarter size will be
possible. If the storms due in fact track across our southeast,
they will also produce locally heavy rainfall over already
saturated soils leading to excessive runoff. Thus, the Flash Flood
Watch will remain in effect for our southeast. /22/

&&

.DISCUSSION...
Issued at 244 PM CDT Fri May 17 2024

Through Saturday: Overall fcst is running generally on track.
Water vapor/RAP analysis this aftn indicated stalled upper low
parked over the central Plains, with widespread moist ascent over
the warm frontal boundary along the Gulf Coast. Earlier heavy rain
has let up, with continued potential for some late aftn
redevelopment in the Pine Belt. With trends shifting southward in
convective allowing models, the flooding threat/Flood Watch were
adjusted southeastward through the evening hours & trimmed back
through Saturday morning. Nearly 99th percentile PWs & 925-850mb
340-350K Theta E will persist across southeastern portions of the
area. Increased destabilization is ongoing as anticipated in a
tight gradient in the Pine Belt, with best potential for any aftn
redevelopment in the Hwy 98 corridor & to I-59 corridors. The
ongoing severe potential could be at earliest in the next few
hours but most likely into late evening to overnight in the Hwy 98
to I-59 corridors in the Pine Belt in southeast MS. Adjustments
have been made to Severe threat in HWO graphics, with main focus
being for damaging wind, hail quarter to golf ball size &
tornadoes possible, especially in the Hwy 98 to I-59 corridors.
Some low tornado threat in sfc mesoanalysis exists if any aftn
redevelopment occurs, with large hail up to golf ball size most
likely in the moderately unstable air & 50-60kts mean bulk shear.
Damaging winds & some hail threat will persist into the overnight
hours. Flash flooding threat will likely peaking back up in the
Pine Belt late tonight but made adjustment to current Flood Watch
to account for a smaller areal configuration & trimmed it down in
time. HWO graphics were adjusted accordingly. As the upper low
swings into the area on Saturday, some persistent westerly bulk
shear around 30-35kts & mid-level lapse rates around 6-6.5 deg.
C/mid 20s vertical totals & freezing levels around 12.5-13kft that
could support some isolated severe threat with damaging winds &
quarter size hail. Timing looks to be the mid- morning through
early evening hours. After the rain & storms move into the Pine
Belt in the morning, there could be the a brief lull in the
Natchez Trace corridor before more scattered to numerous showers &
storms move across the eastern-central portions of MS. In terms
of sensible weather, expect gradual moderation into the low-mid
80s & some increase in heat/humidity.

Late weekend through early next week (Sunday-next Thursday)...

Late weekend (Sunday): Upper low will swing into the
Appalachians, with ridging at the sfc & aloft building in from
west-east. This will drive in drier air into Sunday. Expect
moderation of highs in the mid- upper 80s Sunday, with increasing
potential heat & humidity.

Next week (Monday-Wednesday): As the mid-level & sfc ridge builds
in, increased warm advection will bring up low-level temps into the
upper teens to low 20s degree C at 850-925mb layers. Expect highs to
moderate to seasonably warm into the low 90s & lows in the mid-upper
60s while to low-mid 70s northwest of the Natchez Trace. Heat &
humidity will be on the rise around midweek with heat indices
climbing into mid-upper 90s. Low-level return flow won`t pick back
up until by late Monday evening through midweek, with rain &
storm chances picking back up around mid-late week, northwest of
the Natchez Trace on Wednesday & north of I-20 on Thursday. There
could be some organization to the next trough/frontal system for
some organized convection late week, but there is plenty of time
to iron out as we get closer. /DC/

&&

.AVIATION...
(06Z TAFS)
Issued at 118 AM CDT Sat May 18 2024

VFR/IFR flight conditions for majority of TAF sites with the
exception of VFR flight conditions at GLH to begin the TAF period.
VCSH and -RA will be possible tonight and Saturday as a frontal
boundary moves across the area. Near 17-18Z Saturday, flight
conditions are expected to improve to VFR across all TAF sites. /SW/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       84  65  87  67 /  30  10  10   0
Meridian      85  64  88  64 /  50  20  10   0
Vicksburg     86  67  88  68 /  20  10   0   0
Hattiesburg   86  66  89  66 /  40  10  10   0
Natchez       85  66  88  67 /  20  10   0   0
Greenville    85  67  88  69 /  40   0   0   0
Greenwood     84  65  88  68 /  60  10   0   0

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Flood Watch until 7 AM CDT this morning for MSZ057-058-064>066-
     072>074.

LA...None.
AR...None.
&&

$$

DC/DC/SW