Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 260232

Area Forecast Discussion
National Weather Service Jackson MS
932 PM CDT THU AUG 25 2016

.UPDATE...The 594dam subtropical ridge that has dominated our weather
over the last few days has shifted NE out of the Deep South and is
now centered over E TN. This has allowed for subtle height falls
across the CWA and also resulted in an environment more favorable for
convection, especially along and west of the I-55 corridor, due to
less subsidence. Convection was more widespread this afternoon in the
west as an area of tropical air (2+ inch PWs) was advected around
the nose of the ridge and juxtaposed with 3500-4000+ J/kg of SBCAPE.
Increased midlevel flow, and even 15-20kts of 0-1km shear, was
enough to help storms organize into clusters and a few quasi-linear
segments from the Jackson metro NW into the Delta where a handful of
storms were strong and a few becoming severe. As of 2z, the main area
of convection was located north of I-20 and west of the MS river with
a few scattered storms just west of the Jackson metro. These storms
are propagating NW along mutliple outflow boundary interactions.
Trended PoPs downward from east to west as the storms exit the
CWA/dissipate, with all activity expected to end by 5/6z. Adjusted
temps down in areas that saw convection and locations that are
favored for radiational cooling. Otherwise, added patchy fog across
the western two thirds of the CWA and an area of patchy dense fog
across the NW/Delta where more widespread rainfall occured this
afternoon/evening. /TW/



Most convective precipitation is pushing west of the TAF sites now
and expect quiet conditions overnight with some potential for MVFR
to perhaps IFR fog to develop during the late night and early
morning hours. Any fog will burn off prior to mid morning. From late
Friday morning into the the afternoon, expect greatest threat for
scattered SHRA/TSRA to shift to western portions of the area,
especially at GLH/GWO. /EC/


.PREV DISCUSSION... /issued 358 PM CDT THU AUG 25 2016/

SHORT TERM...Today through Saturday...Analysis of water vapor
imagery indicates that the mid-level ridge of high pressure remains
centered over Tennessee and the Mid South this afternoon. A burst of
afternoon convection associated with tropical moisture wrapping
around the ridge extends from the central Gulf of Mexico through
south Louisiana and into western Tennessee. The greatest chance for
thunderstorms in the ArkLaMiss this afternoon and evening will be
closest to this plume of moisture - northeast Louisiana, southeast
Arkansas, and southern Mississippi. Otherwise isolated to widely
scattered showers and a few thunderstorms will be possible, with
coverage diminishing overnight. Afternoon heat index values have
crept up to near 105 in several locations especially around the Delta
region, and a similarly hot and humid airmass tomorrow could see an
expanded area of heat stress risk. See the latest graphical and text
Hazardous Weather Outlook products for areas covered by a Limited
heat risk today and tomorrow. Patchy fog will likely develop across
portions of the area tonight. The ridge of high pressure should
continue drifting north and east through the end of the week and will
be centered over the Carolinas by Saturday afternoon. This will
lessen heat stress impacts slightly for Saturday. Rain chances lower
however, as a forecasted weak disturbance along the TX/LA coastline
should keep deeper atmospheric moisture confined towards the Gulf

LONG TERM...Sunday through Thursday...There still remains
considerable uncertainty regarding later periods of this forecast, as
forecast models struggle to resolve details of the eastern CONUS
ridge and its interaction with several tropical features through
early next week. The recent trend in model guidance is to limit any
potential impacts to the ArkLaMiss from any tropical systems, however
poor consistency among model runs means lower confidence in the
extended forecast at this time. Generally used a consensus of model
guidance for early to mid-week forecast elements, though also gave
some consideration to typical summertime climatology. For details
regarding any tropical development over the next few days, follow
the latest updates and discussions from the National Hurricane
Center. There is some indication that the ridge will try to build
back towards our region late next week so have kept temps a few
degrees above normal./NF/


Jackson       74  93  74  94 /  39  27  10  10
Meridian      75  94  74  95 /   3  17  10  10
Vicksburg     74  94  74  93 /  39  47  14  10
Hattiesburg   74  93  74  93 /   3  14  10  15
Natchez       73  90  73  91 /  13  40  14  19
Greenville    73  94  75  93 /  38  52  10  14
Greenwood     73  93  75  94 /   8  38  10  14


.JAN Watches/Warnings/Advisories...

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