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Area forecast discussion 
National Weather Service Jackson MS
400 am CDT Thursday Aug 21 2014

Short through Friday night...a little warmer each day
with afternoon heat index values remaining the main concern. Early
morning surface analysis had a 1019mb ridge centered over the Gulf
Coast. Early morning water vapor imagery/RUC analysis showed the
circulation around a 592dam high centered over our area. This middle
level high will strengthen further today and remain centered over
our County Warning Area through Friday night. Together ridging surface and aloft
over our region will allow for a slow warming trend into the
weekend. A rather moist airmass will remain over our area with precipitable waters
of an inch and three quarters to two inches. This will help maintain
upper 60 to lower 70 degree dew points during the hottest part of
the day. The combination of temperatures in the middle to upper 90s
with the high relative humidity will result in maximum heat index
values of 101-104f today and 102-106 Friday. Gfsmos guidance was
again a little too warm and leaned toward a blend of the NAM and
European model (ecmwf) MOS guidance for afternoon highs each day. Model consensus
still hints at late afternoon sea breeze convection trying to drift
up into our southern zones. Have carried isolated wording in the
southwest today and only in our southeast most zones Friday
afternoon. Rain chances will remain very low elsewhere through the
period. /22/

Long term...Saturday through Wednesday...through the weekend heat
and humidity will be be the primary issue as mean ridging continues
through Sunday...which will bring classic August Summer muggy
conditions. 850mb temperatures will be in the upper 20s to around 30c. This
will bring temperatures in the middle to upper 90s through the weekend. With
lows in the 70s heat indices will be a concern. Heat indices will be
around 100 to 107 on Saturday and Sunday. With strong subsidence
rain chances will be rather scarce through Sunday. As we go into
next week moisture will build across the region from the east. This
will give the region a break in warm afternoon high temperatures.
Thus 850mb temperatures will cool some into the middle 20sc. Rain chances
will pick up as deep tropical moisture builds across the region.
Precipitable waters will increase to around 2.2 inches. There will be decent
instability for some convective chances from Monday through
Wednesday with some locally heavy rainfall potential. The mean
ridging will fluctuate some during the upcoming work week.

As far as the tropics are concern models are keeping tropical
systems away from the Gulf of Mexico and pushing possible tropical
systems off the East Coast.

As far as model differences are concern most of the ensembles...
Euro...Navy and UK models keep the mean ridge dominant over our
region. The GFS tried to bring an upper trough over the Central
Plains and eventually pushed a front toward the region for the later
part of the work week...which seems to be an outlier. Models were in
general agreement with the weekend heat and increase in tropical
moisture from the east for next week.

As far as probability of precipitation and temperatures are concern went close to mex and gmos
guidance for the period./17/


Aviation...early morning satellite imagery showed some middle and high
level clouds over Louisiana with very little cloud cover over
Mississippi. All taf sites were observing VFR conds at 830z. A brief
period of MVFR visibilities will be possible from 10-13z over the central and
south but otherwise VFR conds are expected to prevail through this
evening. Very light(<6kts) S-SW winds are expected today becoming
near calm tonight. /22/


Preliminary point temps/pops...
Jackson 96 73 97 73 / 9 6 7 5
Meridian 96 72 97 73 / 6 6 9 5
Vicksburg 96 73 97 72 / 13 6 5 4
Hattiesburg 97 73 98 74 / 11 12 20 9
Natchez 94 74 95 73 / 22 11 13 10
Greenville 95 74 97 74 / 6 5 5 4
Greenwood 96 73 97 73 / 5 5 5 4


Jan watches/warnings/advisories...



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