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000
FXUS64 KJAN 191039
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
539 AM CDT Tue Sep 19 2017

.UPDATE...
Updated for 12Z aviation discussion

&&

.AVIATION...
12Z TAF discussion:

A very humid airmass will result in IFR fog potential until about
14Z, otherwise, today`s primary iso/sct shra/tsra development
should be mainly in the GTR/MEI/HBG corridor from late this
morning through afternoon. Some fog potential may return late
tonight into early Wednesday morning. /EC/

&&

.DISCUSSION...

Today through tonight:

Yet another day starts off with concerns about fog, although the
threat has been trending downward some the past couple of
mornings. At this time we don`t anticipate much concern with dense
fog, which should be very patchy in coverage. Otherwise, the
primary weather concern in the near term will be the diurnal
convective potential as a weak shortwave trough moves east across
the ArkLaMiss today. The consensus in near term guidance is for
the best moisture convergence to set up over eastern/southern
portions of the forecast area later this morning/afternoon. Mid
level lapse rates and flow will show a modest increase due to the
passing trough, so a few strong wind gusts could be a possibility
with storms that develop during peak heating. Expect any storms to
diminish quickly with nightfall with quiet conditions to follow
overnight. /EC/

Wednesday through next Monday...Despite our transition into autumn
late this week, Friday at 3:02 PM CDT to be exact, summer-like
conditions will persist across the region through much of the
forecast period.  High temperatures will generally top out from the
upper 80s to lower 90s.  Afternoon heat index values could reach up
around the century mark, mainly Wednesday and Thursday, as dew
points sit in the low and middle 70s.  Then, with some slightly
drier air working into the forecast area from the east, heat indices
will remain in check during the weekend as dew points generally fall
back into the 60s.  Lows Wednesday night through Friday night will
range from the upper 60s to lower 70s. However, with the
aforementioned drier air over the CWA through the weekend, lows
Saturday night through Monday night look to range from the mid to
upper 60s.

Weak high pressure at the surface will remain over the forecast area
through the period.  However, heights aloft will slightly weaken
over mainly eastern and southern portions of the CWA, as an upper
trough to our east is forecast to slowly slide southwest, thus
undercutting high pressure aloft centered to our north.  This, in
addition to daytime heating and a modestly moist airmass as
precipitable H2O values sit between 1.50-1.75 inches, will result in
chances for mainly isolated to scattered afternoon showers and
storms through the weekend.  This convection will quickly begin
to dissipate around sunset each evening. /19/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       91  71  93  71 /  35  10  31  11
Meridian      90  71  93  70 /  41  13  34  14
Vicksburg     91  72  92  70 /  27   9  25   8
Hattiesburg   90  70  91  69 /  42  17  41  17
Natchez       90  72  91  69 /  27  10  27   9
Greenville    92  72  92  71 /  20   7  20   7
Greenwood     91  72  92  71 /  26   7  26   7

&&

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

&&


$$