Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 242040

Area Forecast Discussion
National Weather Service Jackson MS
340 PM CDT Sun Sep 24 2017


Through Monday afternoon:

Short range explicit convective allowing models have been having a
tough time keeping up with convection the last few afternoons,
typically underdoing rain chances. Such is the case this afternoon
and there are currently a good deal of small showers and embedded
thunderstorms across the region. This activity is drifting
westward with low to mid level flow while pseudo-seabreeze earlier
has instigated a more solid band of thunderstorms in southern
zones, now progressing through the Pine Belt. Decent instability
(SBCAPE values from 2000 to 3000 j/kg) and dry air aloft yielding
downdraft CAPEs in some cases in excess of 1000 j/kg should allow
at least a few storms to produce gusty winds through early evening
(when convection should be rapidly diminishing). We will continue
to advertised the marginal risk of severe storms in the HWO for
areas south of I-20 through early this evening.

Otherwise for tonight, expect clear to partly cloudy skies and
little precip by late evening with decent radiational cooling
conditions and scattered ground moisture allowing for a bit of
patchy fog come daybreak, especially south of I-20. Currently, the
potential for dense fog is not at all great and therefore the
HWO/graphics will be kept clear of any mention of a fog hazard.
Lows will be a little above normal, but still not terribly bad for
late September (mid to upper 60s).

Tomorrow, the upper low overhead will be weakening/filling quite
rapidly and will not have the same cold pocket aloft to aid in
destabilization. There still will be enough instability and
moisture to give rise to isolated afternoon showers and storms
(with the best coverage probably again in southern zones). The
potential for any severe storms tomorrow should be less owing to
lesser overall amounts of instability. Temperatures will continue
to be a little above average, ranging from 86 to 91 degrees. /BB/

Monday night into next weekend...

The current weather pattern will modify slightly early in this
period and more significantly late in the period. The above normal
temperatures will remain through most of the week and the diurnal
rain/storm chances will begin to decrease by Wednesday. The upper
level low centered over the region will begin to weaken and push to
the SE on Tuesday. Although coverage is expected to be less than
previous days, some diurnal type thunderstorms will be possible on
Tuesday with better chances south of I-20. Upper level heights will
begin to increase late Tuesday into Wednesday resulting in a ridge
building over the region. This should help to keep the region mostly
free of storms on Wednesday. A dry front will begin to sweep through
the region on Thursday but not before temperatures increase to well
above their late September averages.

Slightly cooler, drier air will begin to filter into the region
behind the front. A reinforcing front will push through the region
on Friday. A more noticeable change will be present after the
second frontal passage pulls in a cooler, drier continental
airmass over the region. Highs will remain in the low 80s
throughout the weekend. There are no chances of precip in the
package worth noting after Tuesday.


18Z TAF discussion:

Like yesterday afternoon, there will be hit and miss showers and
thunderstorms around the region this afternoon through early this
evening. The best chance of impact at area TAF sites is at
HKS/JAN/PIB/HBG where some brief gusty winds will also be
possible. Conditions should generally remain VFR unless underneath
larger storm, which there is a rather low chance of happening.
Otherwise, anticipate east to southeast winds through the next 24
hours at 10 mph or less with any potential for late night to early
morning Monday sub-VFR conditions mainly confined to PIB/HBG. /BB/


Jackson       67  89  67  90 /  12  23   8  10
Meridian      67  89  68  90 /   9  23   6   6
Vicksburg     68  89  67  90 /  13  20   7  10
Hattiesburg   67  88  66  89 /  19  42  17  22
Natchez       67  89  67  88 /  15  28  10  21
Greenville    67  90  66  91 /   8  15   6   8
Greenwood     68  90  69  90 /   7  14   7   7





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