Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 272343 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
643 PM CDT Mon Mar 27 2017

.UPDATE...
Updated for 00Z aviation discussion

&&

.AVIATION...
00Z TAF discussion: Isold tsra wl cont mainly along and south of
I-20 through 02Z. Additional isold tsra wl be psbl tonight north
of I-20 as a weak cold front drifts into the area. Otherwise, MVFR
cigs are expected to develop and lower to IFR by 11Z again,
especially across the southern half of the area. Conds wl improve
to VFR areawide by 17Z. Isold shra/tsra are expected Wednesday.
/22/

&&

.DISCUSSION...

Rest of today through Tuesday: Numerous showers and thunderstorms
are ongoing across the CWA with a few storms reaching severe
criteria. Latest water vapor imagery shows a mid/upper level
shortwave over SW Missouri with the trough axis extending down the
MS river valley. Current SPC mesoanalysis has anywhere from
1000-2000 J/kg of MLCAPE across the region with moderate to steep
6.5-7 C mid level lapse rates in conjunction with 30-40 kts of
effective bulk shear. This will help to maintain a severe
thunderstorm threat across the majority of the area with the main
threats being large hail (some of which could exceed golf ball
size in the strongest storms) and damaging winds. Shear remains
weak, especially in the low levels, and LCL heights are relatively
high so any tornado threat will remain isolated to the strongest
storms at best. The best potential for severe weather will be
along and north of the I-20 corridor through the early evening
hours, however severe storms are possible across the entire area.
Storms will tend to weaken into the evening as instability wanes
and the best forcing for ascent continues to pull out to the north
and east. Scattered shower and isolated storm potential will
remain during the evening in the NW where the lingering frontal
boundary will become quasi-stationary. Otherwise, fog potential
will return in a moist boundary layer, especially across the SE
and in the fog prone areas. Added mention in the forecast, but
left it out of the HWO for now as confidence is not high enough at
the moment. For Tuesday, a lingering boundary across central MS
will keep a warm and moist airmass in place. Daytime heating will
allow for weak to moderate destabilization but with weak lapse
rates and no source for forcing any storms that develop will be
isolated to scattered at best. No severe weather is expected with
this activity, although a strong storm or two cannot be ruled out.
/TW/

Tuesday Night through Monday:

The active weather pattern will continue through this work week
and the upcoming weekend as a parade of upper lows dig into the
Desert Southwest and move east across the country. The next period
to watch for the ArkLaMiss region specifically will be late
Wednesday night through Thursday night. A deepening low pressure
system over the Southern High Plains on Wednesday will lift toward
Missouri by Thursday night. While the finer details of this system
may change, the current thinking is that an MCS will approach
northeast Louisiana and southeast Arkansas by late Wednesday
night but should be weakening as it enters our area and outruns
the best instability. Warm, moist advection will continue across our
region through the day Thursday with dew points climbing into the
mid 60s and around 1000-1500 J/kg of MLCAPE developing by the
afternoon. An additional round of convection is expected to
develop under these conditions before a cold front sweeps in with
drier and cooler air Thursday night. At this time, all modes of
severe weather look possible during the day Thursday with an
increasing heavy rain threat before the cold front moves through.
The next system looks to take shape by late in the weekend and
will possibly bring another round of severe thunderstorms through
the region some time Sunday into Monday. Be sure to tune in for
updates throughout the week as the details come into better focus
for these next few rounds of severe weather. /NF/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       64  83  63  87 /  51  25   9   2
Meridian      63  82  61  86 /  39  26   8   3
Vicksburg     65  82  63  86 /  36  24   9   5
Hattiesburg   63  83  63  86 /  24  22   6   2
Natchez       65  83  64  85 /  21  23   9   8
Greenville    60  78  62  83 /  43  17  14   3
Greenwood     61  79  62  85 /  62  21  13   4

&&

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

&&

$$

TW/NF/22



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