Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 061810
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1210 PM CST SAT FEB 6 2016

.SHORT TERM: (Today and Tonight)
Issued at 315 AM CST Sat Feb 6 2016

The elongated and positively tilted upper trof stretching from
the Great Lakes into the southern Plains is producing a good deal
of cloudiness and possibly a few sprinkles near the Lake of the
Ozarks. This upper trof and the weak surface trof/reflection will
move to the east of the CWA by midday. Clouds will diminish in its
wake while surface winds become westerly and low level warm
advection ensues. Temperatures should see a nice climb over
yesterday`s numbers with highs today around 10 degrees above
average. The low level warm advection regime will persist tonight
with clouds again on the increase well in advance of the next
system.

Glass

.LONG TERM: (Sunday through Friday)
Issued at 315 AM CST Sat Feb 6 2016

Winter returns.  Big changes ensue this period as a highly
amplified pattern develops Sunday night into Monday, featuring a
strong ridge/block along the west coast and broad deep trof over
the eastern 2/3rds of the Nation. This pattern will unfold as a
upper low/trof digs southeastward from the northern Plains/Upper
MS Valley Sunday into Monday. Southwest winds and low level warm
advection will continue the first part of the day on Sunday
resulting in another day of above average temps. However the lead
short wave and height falls will move into the mid MS Valley
during the afternoon sending the first cold front through the area
by early evening. There could be some spotty light showers in the
afternoon with the short wave producing weak large forcing and
ascent from far east central MO into IL. The real surge of cold
air comes in on Sunday night as the upper low/trof continues to
dig southeast and sends another cold front through the area
accompanied by increasing and gusty northwest winds and strong
CAA. Vorticity maxima within the cyclonic flow aloft will help
produce areas/small bands of light snow. Monday will feel like a
good old winter day with gusty northwest winds and much colder air
producing blustry conditions. Areas/small bands of light snow/snow
showers will continue to impact areas on Monday, and some
locations through the duration could see small accumulations
ranging from a dusting up to an inch.

The deep eastern trof will continue to dominate through midweek
resulting in below average temperatures. The amplitude of the
upper trof will diminish during the later half of the week with
broader cyclonic northwest flow aloft. We will have to keep a wary
eye on fast-moving disturbances within this flow. The models show
one such clipper system in the Wednesday/Wednesday night time
frame, however can`t agree on location and impacts and this also
varies with each successive model run. It appears tempertures will
approach normal levels by week`s end, however the ECMWF has
another northwest flow disturbance on Friday worth watching.

Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1135 AM CST Sat Feb 6 2016

VFR through the period with increasing mid/high clouds. Winds will
back slightly overnight then turn westerly tomorrow behind a cold
front.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX


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