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Area forecast discussion...updated 
National Weather Service Jackson MS
913 PM CDT Sat may 23 2015

any storms that were in NE la have weakened and only a slight chance
of showers and isolated storms are possible through 04z tonight
before the hrrr/hi-res arw/nmm indicate showers dwindling and being
dry throughout the overnight period. It looks as though moisture
advection will stay low enough to keep the region dry through 15z
Sunday. Only changes to the going forecast were to trim probability of precipitation a
little further west for the next couple of hours and remove probability of precipitation
after 04z. Also slightly adjusted lows upward along/west of I-55
corridor due to cloud cover in the region and low level flow staying
up due to gradual increase in surface pressure gradient from developing
low pressure in the Southern Plains. Areas in the NE will be slightly
cooler due to slightly less moisture/cloud cover from high building
into the eastern Continental U.S. While more moisture and clouds will be moving in
from the W/SW. Adjusted hourly temperatures/dewpoints/sky grids to current
trends. Rest of the forecast is on track. /DC/


Aviation...southeast winds from 5 to 10 miles per hour are expected through
the night at all sites with conditions mainly VFR during this time. A
few exceptions towards dawn may occur south of I-20 where MVFR
ceiling and visible restrictions are possible (along with perhaps a stray
shower). After sunup tomorrow MVFR ceilings may become a little more
widespread...although mainly VFR flight cats are once again expected
by midday to early afternoon as winds veer a few points and stiffen
up to occasionally 20 miles per hour. Showers and storms by tomorrow afternoon
will be far more numerous than has been the case the last few
days...especially west of I-55. /Bb/


Previous discussion... /issued 444 PM CDT Sat may 23 2015/

Short term...tonight through Monday night...surface analysis this
afternoon had high pressure centered over the middle Atlantic Seaboard
with low pressure over eastern New Mexico. Our County Warning Area was still being
dominated by the surface high and a drier air mass but a warm front
associated with the surface low was approaching our southwest most
zones. Most of our County Warning Area will remain dry tonight but a few showers and
thunderstorms will be possible late this afternoon and early evening
over our southwest. The surface high will shift farther east Sunday
while the surface low moves over the plains. Upper levels will
amplify with troughing over the western Continental U.S. And ridging over the
southeast Continental U.S.. this will spell a wet weather pattern for our County Warning Area
that looks to last through Wednesday. Wind fields will increase over
our region Sunday as a shortwave approaches including the right rear
quadrant of an upper jet streak. The shortwave is perhaps a little slower
than previous runs over the northwest portions of our County Warning Area Sunday
evening. Deep moisture is expected to increase through the day Sunday
with lower 70 dewpoints and precipitable waters above an inch and three quarters over
the western half of our County Warning Area. A few strong to severe storms with wind
gusts up to 60 miles per hour and locally heavy rain will be possible from late
afternoon into the early evening hours mainly over our western zones.
Considering the helicity some models depict over the area as well...a
tornado or two cannot be ruled out. We will continue to mention this
potential in the severe weather potential statement. Overall activity will wain with the loss of
heating through the evening but rain chances will continue through
the night. Little change is expected Monday with heating contributing
to an increase in activity during the day. The most intense
convection is expected early Monday evening in our west as another
shortwave tracks to the northeast across the region and combines with
our moist an unstable air mass. A few strong storms along with
locally heavy rainfall will be possible. /22/

Long term...Tuesday through Saturday...the main shortwave trough
will move northeast of our County Warning Area Tuesday but the mean upper level
trough axis and core of the upper level jet will remain just west of
our area. Together these features will contribute to another cloudy
and wet day. Models suggest heaviest rainfall will be over the
northwest half of the area again where one to two inches may fall.
Wednesday another round of rain is expected as another shortwave
moves across our region and combines with our moist air mass and
daytime heating. Lower chances for rain are expected Thursday and
Friday as middle level ridging strenghtens from the western Gulf across
our County Warning Area. Daytime heating of our moist air mass that will still reside
over our County Warning Area should lead to atleast isolated diurnally driven
convection each day. The European model (ecmwf) is slower than the GFS with a closed
low moving through the Central Plains and therefore drier for US
Saturday. Assuming a little faster progression...rain chances look to
increase from the west next weekend. /22/


Preliminary point temps/pops...
Jackson 70 85 70 82 / 9 48 53 70
Meridian 66 86 69 81 / 7 32 49 64
Vicksburg 70 86 71 81 / 13 50 72 74
Hattiesburg 71 86 71 83 / 11 43 50 60
Natchez 71 85 70 82 / 15 67 69 74
Greenville 70 85 70 81 / 13 65 77 74
Greenwood 69 85 70 80 / 6 50 68 73


Jan watches/warnings/advisories...


District of Columbia/bb/22

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