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Area Forecast Discussion (AFD)

Issued by Jackson, Mississippi (JAN)

FXUS64 KJAN 231807 AAA

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
107 PM CDT Fri Mar 23 2018

Updated for 18Z aviation discussion


18Z TAF discussion: 
Overall VFR conditions are expected through this afternoon and
most of the forecast period. Some gusty winds are ongoing, up to
15-20mph, in most areas, but especially the Delta (GLH & GWO).
Expect these winds to wind down somewhat after 24/00Z but should
remain near 8-10kts through the overnight hours before southerly
winds may pick back up late tonight. Overall some mid-high layer
clouds will prevail this afternoon before some low-mid layer
clouds, possibly MVFR ceilings, after 24/08-12Z. The lower MVFR
ceiling in the west will be on the early side (GLH, GWO, JAN & 
HKS) while later at eastern TAF sites (GTR, MEI & HBG). Due to 
lighter winds at HBG, can't rule out some patchy MVFR visibilities
near daybreak, but with increasing clouds and wind that should 
lift by mid-morning ~24/14Z. Some light showers will move into 
northern TAF sites by mid-afternoon tomorrow but not enough 
confidence exists to introduce in the TAFs at the moment. /DC/


Overall a continued quiet & dry forecast is in store today. 
As a a shortwave and surface low/stalled frontal boundary push 
through Missouri and into the mid-Mississippi Valley, expect 
gradual increase in pressure gradient from the west. The very 
light rain showers have tapered off just to our north & any
chances will stay to our north into the mid-South area. This will
help winds gust in the 15-20mph range or so, especially in the 
Delta. Otherwise, with increasing warmth in the low-levels and 
slow increase in mid-high level moisture, expect above normal 
highs in the mid-upper 70s with increasing mid-high level clouds. 
With some drier dewpoints around & increasing pressure 
gradient/winds, we should mix well. However, lowered highs as even
efficient mixing won't support too far into the upper 70s. Even 
with gusty winds and dry air around, think any fire danger will 
be very limited & not enough to mention in the HWO/graphics. /DC/

Prior discussion below: 

Today and Tonight:

Surface high pressure ridging will continue to move east of the 
area today with southerly flow increasing. A nice day is on tap 
with partly cloudy skies and high temperatures in the mid/upper 
70s. The surface pressure gradient will begin to increase this 
afternoon with gusts from 20 to 25 mph possible, especially across
the delta.

A weak short wave will move across the northern portions of the
area early on Saturday, and this may kick off a few light showers
in the morning. Overnight lows will fall into the mid/upper

Saturday through Thursday night: 

Models remain in good agreement that a shortwave and attendant 
surface low over the Central Plains Saturday morning will continue 
weaken through the day as they track east across the Tennessee 
valley. The pressure gradient between the low and a surface ridge 
across the northern Gulf will result in a gusty south wind that will 
increase surface dew points back into the 60s and PWATs from near 
one inch to near an inch and a half during the afternoon. Daytime 
heating will lead to a few storms developing primarily north of 
Interstate 20. Warmer than normal temperatures are also expected as 
the southern half of the CWA tops out in the lower 80s. As the 
shortwave and surface low all but dissipate Saturday night, the 
trailing cold front will sag into our CWA and stall. The front is 
expected to stall near the Interstate 20 corridor. The front will 
remain the focus for convection through Sunday before lifting back 
north late Sunday night into Monday morning. Coolest temperatures 
and greatest rain chances Saturday through Monday will be carried 
across the northern half of our CWA. Our southern half will remain 
warmer than normal and mostly dry through the period. Monday night 
through Tuesday a closed low dropping over the desert southwest will 
help strengthen ridging surface and aloft over the eastern CONUS. 
This will send a backdoor cold front into our CWA. The resulting 
cooler and drier air will limit rain chances over the eastern half 
of the CWA Monday night and Tuesday but the chances for rain will 
increase back across the whole CWA from the west going into 
Wednesday. There are timing and evolution differences in the models 
concerning the closed low and attendant surface low but an axis of 
prolonged heavy rainfall is still expected to set up just west of 
our CWA by mid week. The closed low is expected to lift out to the 
northeast and open up into an upper level trough that will be more 
progressive. As it does so, the axis of heavy rainfall will likely 
shift east across our CWA producing several inches of rain. This 
looks to occur Wednesday night and Thursday with dry weather 
expected again by Friday. /22/  


Jackson       57  80  62  78 /   1   3   7   9 
Meridian      55  80  61  77 /   1   2   4  11 
Vicksburg     59  81  62  78 /   1   6  14  10 
Hattiesburg   55  82  61  80 /   1   2   4   4 
Natchez       59  81  62  80 /   1   3   6   4 
Greenville    59  76  58  67 /   1  15  30  18 
Greenwood     58  76  58  70 /   1  11  31  21