Area Forecast Discussion
Issued by NWS Jackson, MS

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000
FXUS64 KJAN 161045
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
545 AM CDT Wed Aug 16 2017

.UPDATE...
Updated for 12Z aviation discussion

&&

.AVIATION...
12Z TAF discussion:

Widespread LIFR/IFR category stratus should mix up to MVFR by mid
morning with VFR conditions prevailing by afternoon. Otherwise,
the main aviation weather concerns will be for scattered
afternoon TSRA which are likely to impact TAF sites for a brief
period at least before dissipating after 00z. /EC/

&&

.DISCUSSION...

Today through tonight:

Hot and humid air will help to keep rain chances high in the near
term. A fair amount of south-southwesterly low level wind flow
(20kt below H850) will combine with a very moist airmass (H850 Td
~ 16 C and PW > 2 inches) and daytime heating to bring
considerable coverage of shower/thunderstorm coverage today.
Recent CAM guidance has been showing development of convection
prior to daybreak over north central portions in upper level col
region, but the trend has been for most development to hold off
until late morning and afternoon, especially in the HRRR. Will
continue to monitor closely for signs of convective precipitation
in the near term as locally heavy rainfall could be a concern if
it develops.

Later today, storms could manage to produce strong wind gusts in
addition. Because of the earlier start to convective development
today, guidance is slightly cooler with highs expected to be
slightly below climatic average. However, high dewpoint
temperatures in the the upper 70s will still support heat indices
in the 100-105 range. Any storms continuing into the early evening
are expected to wind down quickly with a warm and muggy overnight
to follow. /EC/

Thursday through early next week:

Upper level heights will begin to dampen over the eastern US on
Thursday with upper flow over the region becoming more zonal. A weak
surface boundary associated with an upper level low moving from the
Eastern Plains towards SE Canada, will approach the ArkLaMiss from
the NW on Thursday and serve as a focus for mainly afternoon
convection through Friday as it slowly moves through the region.
Areas that are not impacted by thunderstorms on Thursday afternoon
will see temperatures climb into the lower 90`s. Dewpoints will
climb to the upper 70`s just south of this weak front. This will
result in heat indices ranging from 105-108 mainly in Delta regions.
A limited heat threat has been included in the HWO for Thursday.
Slightly drier air in the north and more widespread convection in
the south on Friday may result in lesser chances of heat indices
exceeding 105 degrees.

Upper level heights will begin to increase again this weekend as
upper ridging in the west begins to spread east. Southerly flow in
the lower levels will continue to provide moisture from the Gulf
through early next week as the ridge remains in place. Pwats will
remain between 1.75"-2.25" through the period. Afternoon
thunderstorms will be possible each day and highs in the lower 90`s
are expected from Saturday through at least Tuesday. /JPM3/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       90  74  92  76 /  58  19  20  16
Meridian      91  74  92  75 /  58  22  18  12
Vicksburg     90  75  93  75 /  59  19  25  19
Hattiesburg   91  74  93  76 /  57  25  18  10
Natchez       89  74  92  75 /  74  20  22  16
Greenville    90  75  93  75 /  41  17  37  21
Greenwood     89  75  92  75 /  57  19  34  21

&&

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

&&


$$



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