059
FXUS64 KJAN 091949 AAC
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
249 PM CDT Sun Jun 9 2024

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 1023 AM CDT Sun Jun 9 2024

An upper-lvl/sfc ridge is expected to shift southward, allowing a
frontal boundary to progress towards the area. Majority of the
convective activity seen on GOES-16 is found along and ahead of a
frontal boundary. Ahead of the frontal boundary,
westerly/southwesterly flow will push additional moist air into the
region. As dewpoints reach the lower 70s, humidity is expected to
increase. Expect afternoon temperatures to reach the mid 90s. With
temperatures in the mid 90s and increasing humidity, heat indices
near 105 degrees will be possible. HWO graphics will continue to
advertise the heat threat.

In addition to increasing dewpoints, anomalous SBCAPE/DCAPE values
and deep-layer shear over the region will help promote some
organized convection, resulting in possible strong to severe storms
this afternoon and into this evening. After modifying the 12Z
morning sounding, combined with the afternoon heat and humidity,
afternoon microburst potential in the Hwy 82 corridor is in the 7-9
range, with supports likely potential for severe storms. SPC added a
"Slight" risk to areas across HWY 82 corridor and expanded the
"Marginal" risk to areas as far south as I-20. Main concerns remain
damaging wind gusts of 60-70mph and quarter size hail or potentially
larger, as efficient hail growth is possible due to large CAPE in
the hail growth region of -10 to -30 degree C. HWO graphics are
updated for the and severe weather/heat risk and updates are out. /SW/

&&

.DISCUSSION...
Issued at 429 AM CDT Sun Jun 9 2024

Today and Tonight:

A surface high which has been over the area will continue to weaken
and shift southward as a cold front arrives from the north today.
Upper-level riding farther south over the Gulf Coast will suppress
rain chances through the day, but gradually falling heights across
the Mid-South down into northern Mississippi will allow for some
convection north of Interstate 20 by the afternoon. Pooled moisture
along the cold front and heating to the south should result in about
3000-4000 J/kg of SBCAPE in northern MS and southern AR. Forecast
soundings show little to no inhibition during peak heating and DCAPE
values in the 1500-1600 range. Any disturbance such as outflow from
storms to the north could trigger deep convection. Deep-layer
westerly wind shear values will be around 25-30 kts in that area, so
enough flow to help with some organization of storms if they should
develop. Various high-res guidance members provide such a solution,
with most of the storm threat pushing east into Alabama by late
evening/early tonight. Given the strong heating south of the front
and modest flow aloft, damaging wind gusts will be the primary
hazard with any storms though hail is possible as well. Additional
chances for some showers or storms will continue into the overnight
as the main front pushes southward.

Heating and moisture south of the front will also result in some
dangerous heat concerns across the forecast area today. Guidance has
trended higher on the dew points for today, with less deep mixing of
dry air compared to yesterday. Low 70s dew points and afternoon
temps pushing the mid 90s should result in peak heat index values
near 105 degrees, plus or minus. Expanded the Limited threat heat
outlook to cover the forecast area, but the best chances to hit 105
currently appear to be focused from around Jackson/Vicksburg and
northward into the Delta. /NF/

Monday through Saturday:

Monday, northerly flow should continue as the cold front
continues to slowly pass south/southeast through the area. We can
expect to see some lingering scattered storms across and ahead of
the frontal boundary. Storm coverage will be confined and storms
are expected to be largely sub-severe thus there will be no
outlooks for Monday. Behind the front Tuesday-Wednesday, drier
and cooler air will advect into the north and high temperatures
will dip slightly into the mid to high 80s for most of the area
with regions of the Pine Belt remaining in the low 90s. Heat
stress will be much less concerning with only areas of the Pine
Belt having max heat indices nearing 100 degrees. Rain chances
will continue through the week for the southern half of the CWA as
a broad area of low pressure over the Gulf of Mexico feeds in low
level moisture to the area. Storm coverage looks to be more
isolated to scattered across the south and southeast. The end of
the long term looks to be very uncertain as guidance has struggled
to produce any persistent weather pattern but ridging across the
southeastern states looks to be the best solution. This will help
to keep the disturbance into the Gulf of Mexico through Saturday.

&&

.AVIATION...
(18Z TAFS)
Issued at 249 PM CDT Sun Jun 9 2024

VFR flight conditions and westerly/southwesterly winds near 5 mph
are expected to start the TAF period. Showers and thunderstorms will
be possible in the afternoon and evening hours at northern TAF sites
as a cold front moves into the area. 40-50 kt gusts and 1.0 in hail
with brief reduction of ceilings and visibility will be possible at
sites receiving these storms. MVFR flight conditions will be
possible at TAF sites north of I-20 around 07Z Monday for as the
front migrates through the area, returning to VFR conditions after
13Z Monday. Remaining TAF sites are expected to remain at VFR
through the end of the period. /SW/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       71  86  65  87 /  10  20   0  10
Meridian      71  88  64  88 /  30  20   0   0
Vicksburg     71  86  65  87 /  10  20   0  10
Hattiesburg   73  92  68  91 /  10  50  10  10
Natchez       70  88  68  88 /   0  30   0  10
Greenville    70  85  64  86 /  30  20   0   0
Greenwood     69  85  63  86 /  40  20   0   0

&&

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

$$

NF/KP/SW