Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 202326
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
626 PM CDT Fri Oct 20 2017

.UPDATE...
Updated for 00Z aviation discussion

&&

.AVIATION...
00Z TAF discussion:
VFR conditions will prevail through the period but mid and high
clouds will continue to be on the increase as moisture gets pulled
back into the area. Saturday will remain dry and winds will be out
of the southeast around 5-10kts. /28/

&&

.DISCUSSION...
Tonight through Saturday:

The primary focus will be centered beyond the near term forecast as
a major shortwave trough and associated cold front advance toward
the Lower Mississippi Valley later this weekend. For now, a dry
airmass is keeping the weather quiet for the ArkLaMiss, and expect
rain-free weather to continue through tonight. As we approach
daybreak Saturday, low level winds will begin to veer to a more
southerly direction with the approaching trough, and increasing
moisture transport/convergence should support shower development,
especially over western/southern portions of the forecast area, but
rainfall amounts should be light. Have continued to show increasing
cloud/rain chances for Saturday, but temperatures may still climb
into the mid 80s before clouds thicken up. /EC/

Sunday through next week:

An upper low pressure system is expected to cutoff from a digging
trough in the mid-Mississippi Valley region on Sunday. As this low
pressure passes over the area, a cold front will accompany this
passage as well. As the models come into a bit better agreement on
the timing and evolution of this system, it appears the system and
rainfall should completely exit the region by Monday night. There
may be a couple rounds of rainfall between Sunday and Monday as
cyclogenesis occurs and the low begins to lift northeast Monday.
During all of this, the severe potential remains rather low. CAPE
values are decent and low-level moisture will be abundant but poor
lapse rates and the evolution of the cyclogenesis over the area
will limit severe storms. This system however has plenty of
moisture flowing into it from the Gulf. PWs ahead of the front
will be near 2" on Sunday. Storm total rain amounts with this
system could be as high as 4" in some places, with widespread 2"
likely. Our area has been quite dry lately though and part of the
area is under a D1 drought. With the abundant moisture available,
convective rain rates could be high within the strongest storms.
This being said, where rain rates are high enough, some limited
flash flooding will be possible. This has been added to the HWO
and the threat will continue to be monitored.

After the cutoff low exits to the northeast on Tuesday, the upper
trough digs deeper into the region and brings a reinforcing cold
front through the area. A much drier airmass is expected behind
this front. PWs will likely drop below 0.5" and dewpoints will
drop into the 30s. Height falls will be significant going into
Wednesday morning and will bring the coldest temperatures of the
season so far. Lows Wednesday morning may dip into the upper 30s
in some places. High temps will mostly be in the 70s next week
with Wednesday topping out in the mid 60s. /10/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       63  84  68  79 /   4  27  16  83
Meridian      59  83  65  80 /   1   7   4  66
Vicksburg     65  85  68  78 /   6  35  22  87
Hattiesburg   63  83  68  79 /   3  38   7  79
Natchez       67  84  69  78 /   3  41  27  86
Greenville    63  83  67  77 /   9  27  30  86
Greenwood     62  84  68  78 /   5  13  10  79

&&

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

&&


$$

28


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