Area Forecast Discussion
Issued by NWS Jackson, MS

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468
FXUS64 KJAN 201133 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
633 AM CDT Tue Apr 20 2021

.UPDATE...
Updated for 12Z aviation discussion

&&

.AVIATION...
12Z TAF discussion:
VFR conditions prevail across the region this morning as high
clouds spread across parts of LA and South MS. clouds will
decrease through the day, and SW/W winds may be gusty at times.
Winds will increase and shift to the NW/N tonight as a cold front
moves southeastward across the region. Precip will be limited
along the front, but SHRA can`t be ruled out around GWO/GLH.
Ceilings will also lower behind the front and may approach MVFR
around GWO/GLH/GTR overnight before improving again closer to
daybreak. /DL/

&&

.DISCUSSION...
Today and tonight...
High clouds are moving across much of the area this morning.
Though radar shows echoes as low as 6 kft across South MS, there
is a rather dry layer below this, thus what little precip is
making it to the surface will be in the form of scattered
sprinkles. Heading through the day, we`ll clear out and become
seasonably warm, with SW/W winds breezy at times. A cold front
will move into the Delta around sunset, continuing across the area
overnight. With the limited period of return flow ahead of the
front and PW merely surging to 0.8-0.9 in, only a diminishing band
of light showers is expected across East AR and North MS
tonight... furthering diminishing to sprinkles then just a band of
clouds as the front pushes farther south and east. Earlier on in
the evening, gusts to around 30 kt will be possible behind the
front in the upper Delta. If confidence was higher in this
occurring over a larger area, a limited gradient wind mention
would be added to the HWO, but for now, this is something we will
continue to monitor. Though few areas will receive precip, none of
us will miss out on the gusty N/NW wind overnight with sharp cold
advection resulting in wind chills in the 30s in some areas by
Wednesday morning. /DL/

Wednesday through Monday...
High pressure begins to build in from the Plains going into mid week
behind the front, bringing in cooler air to the region. 500 mb flow
shifts to a more zonal pattern through the end of the week. 850 mb
temps drop considerably with the trough from 9C Tuesday afternoon to
2C in less than 24 hrs behind the front. High temps for Wednesday
drop into the lower 60s as a result for most of the area.  The high
pressure ridge axis moves into the region and immediately over the
FA Wednesday night.  Winds become light and variable overnight.
Clearing skies will set up fairly efficient radiational cooling.
Temps drop by early Thursday morning into the upper 30s east of the
I-55 corridor. Concerns for frost potential in the far NE where the
lows may dip closer to the mid 30s. There are still some variations
in the guidance, with some concern for cloud cover prohibiting the
drop. That being said, the drier airmass and the fact that guidance
has options that are still cooler than the forecast...will keep the
cool forecast in place. Keeping the mention in the weather grids as
well as the limited mention in the HWO.  Easterly flow through
Thursday will keep the warm up limited...though several degrees
warmer than Wednesday.  Southerly flow kicks in at least briefly
Friday ahead of the next wave/storm system.  Once again, a surge of
moisture with the return flow will push the dwpts back into the
50s/lower 60s by Friday night with increasing chances for showers
and thunderstorms from Friday afternoon through Saturday. ECMWF/GFS
starting to come into alignment with the depth of the upper wave
after it moves over the California coast and into the desert SW. But
the surface low solutions still differ considerably with the ECMWF
having a faster and more northerly track. GFS is still slower and
weaker/amorphous with the surface circulation going into the
weekend, though partially due to feedback.  The precip fields are
starting to hint at a concentration of qpf along a possible warm
frontal feature Friday night into Saturday.  Expect some changes
with timing in the extended...as well as qpf/qpf axis, but so
far...looks like a wet, but warmer start to the weekend. Track and
timing will most definitely be impacting the threat for severe
weather for Saturday as well...specifically whether or not there
is enough ongoing convection/showers from the overnight to
inhibit stronger convection going into peak heating ahead of the
front.  /HJS/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       77  43  62  40 /   1   0   0   2
Meridian      77  45  64  38 /   3   0   0   2
Vicksburg     78  43  62  41 /   0   0   0   2
Hattiesburg   77  48  66  39 /   6   0   0   0
Natchez       76  44  62  41 /   1   0   0   0
Greenville    76  39  60  42 /   0  13   0   5
Greenwood     76  40  61  41 /   1  10   0   5

&&

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

&&


$$

DL/HJS



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