Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 221402 AAA

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
902 AM CDT Fri Sep 22 2017

Updated for morning discussion.


Some isolated convection has managed to fire up this morning near
a 0-3km theta-e bullseye over northeast MS. Would expect this to
diminish somewhat through the late morning diurnal convective min
period then begin breaking out again with the heat of the
afternoon. Made some adjustments to temps and sky cover as the
convection is obviously affecting these fields at present. /26/

Prior discussion below:

Today and tonight...

This afternoon marks the first day of fall as the Autumnal Equinox
occurs at 3:02pm. However, it certainly won`t feel like fall as our
summer-like weather pattern will remain firmly entrenched over the
region. High pressure aloft will remain sprawled across the eastern
third of the country, as troughing occurs across the western part of
the CONUS. Temperatures today will once again be above normal for
September, with highs expected to reach the lower 90s. Afternoon and
early evening isolated to widely scattered showers and storms will
be possible once again today. However, coverage is expected to be on
the low side as was the case yesterday. Any activity that develops
will diminish in the evening, leading to another mild night with
lows in the upper 60s/lower 70s. /28/

Saturday through Thursday...

The period will start out with a rather amplified synoptic regime
across the CONUS as a stout longwave trough digs over the western
states. This will help to amplify downstream ridging from the
Central Plains through the Midwest, but the ArkLaMiss will remain
relatively spared from the higher heights and thus heat stress
issues thanks to an upper-level low retrograding beneath the ridge.
While temps will remain above average in the upper 80s to low 90s,
dewpoints mixing out into the upper 60s to low 70s will help to
preclude any heat stress issues. The upper-level low will meander
over the ArkLaMiss through the weekend and into Monday before
getting picked up by the western CONUS trough that will be lifting
through the Midwest. Isolated to scattered diurnally driven
afternoon showers and storms will be possible each day through
Tuesday before drier air wedges in from the east. Shortwave ridging
will build in behind the departing upper-level low Tuesday and
Wednesday allowing high temps to climb back into the low 90s ahead
of an advancing cold front. Latest 00z global models disagree with
the timing of this front as the ECMWF remains faster with the front
pushing through the CWA on Thursday while the GFS is slower with the
front coming through on Friday. The ECMWF also has a dry frontal
passage while the GFS remains more moist with an impressive
shortwave trough diving through the Great Plains. Went with a blend
of the two solutions for now with a slight lean towards the drier
and faster ECMWF given the spatial removal of the upper-level
forcing from the front. Regardless, this cold front will bring in a
much more seasonable fall airmass by next weekend. /TW/


12Z TAF discussion:
Mostly VFR conditions are prevailing this morning. Some sites have
seen patchy fog briefly develop, which has caused visibilities to
drop to MVFR to IFR for a brief time but these quickly return to
VFR categories. VFR conditions should prevail through much of
today with the exception of any showers/storms that develop and
cause a brief reduction. These should primarily affect
KMEI/KHBG/KJAN. Storms should diminish by 02Z and VFR categories
should prevail through much of tonight. /28/


Jackson       90  70  90  69 /  19   7  17  16
Meridian      91  69  90  68 /  26   8  18  16
Vicksburg     91  70  90  68 /  16   4  18  16
Hattiesburg   90  69  88  68 /  26  10  17  16
Natchez       90  70  89  68 /  17   9  17  16
Greenville    92  70  91  70 /  12   3  19  16
Greenwood     90  70  91  69 /  15   4  18  16




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