000
FXUS63 KLSX 160027
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
727 PM CDT Sat Mar 15 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 405 PM CDT Sat Mar 15 2014

Rain will spread northeastward as a southern stream shortwave over
the TX Panhandle moves northeastward towards southwest MO and a
northern stream wave now over WY and western CO drops
southeastward through the Plains on the heels of the southern
stream shortwave. Upper level divergence will be increasing
tonight, particularly across the southern half of our forecast
area. At the same time a cold front will be dropping southward
through our area. The models were depicting a frontogenetical band
of snow late tonight across northeast MO and west central IL
behind the surface front. Accumulations of up to one inch are
expected across northeast MO. Further south rain is expected,
possibly changing to sleet towards morning across central MO as
the surface layer cools to the freezing mark with an elevated warm
layer above freezing.

GKS

.LONG TERM:  (Sunday through Next Saturday)
Issued at 405 PM CDT Sat Mar 15 2014

Deformation type precipitation is expected on Sunday as a
surface/850 mb low moves across AR and into TN and northern portions
of MS AL.  Most of the precipitation will be south of Interstate
70. The precipitation type across southeast MO and southwest IL
will be initially rain, but will change to sleet and eventually to
snow as the elevated warm layer erodes. There may also be a brief
period of freezing rain in some areas before the rain changes over
to sleet. Will issue a winter weather advisory across southeast
MO and southwest IL into central MO where 2 to 4 inches of snow
along with sleet is expected. Temperatures will be nearly steady
on Sunday with cold air advection, low level clouds along with
precipitation. Surface winds will be very strong and gusty due to
the tight surface pressure gradient between the strong surface
ridge over the northern Plains and the surface low well south of
our area. The precipitation should shift southeast of our area by
Sunday evening as the upper level trough shifts east of the region
and the surface ridge builds southeastward through our area.
Below normal temperatures are expected Sunday night with a
clearing sky and a diminishing wind. A warming trend will begin
Monday afternoon as southerly flow returns as the surface ridge
shifts east of our area. An upper level trough and associated cold
front will mvoe eastward through the region Tuesday night. It
appears that most of the precipitation will remain north of our
forecast area along and north of the track of the surface low.

GKS

&&

.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 649 PM CDT Sat Mar 15 2014

Latest surface analysis shows quasi-stationary frontal boundary
extending from southern Indiana through northeast Kansas then
southwest to area of low pressure over south-central Kansas.
Quasi-statinnary frontal boundary expected to move southward over
night acrpss easterm Missouri and southwest Illinois. A weather
system over Texas is forecast to move east and bring light rain
over the area after midnight and then change over to a mixture of
ice pellets and snow after 1000 UTC over STL area and 0900 UTC
over central Missouri. Light snow will continue during the morning
hours over STLarea. surface winds will be gusty up to 30 kts from
the northeast early Sunday morning.

Specifics for KSTL: Quasi-stationary front expected to move south
across STL between 0300 and 0400 UTC. Surface winds will becoming
northeast with gusts 25 to 30 kts after 0900 UTC. Rainshowers
forecast to begin after 0600 UTC with rain changing to sleet and
snow after 0900 UTC. Surface winds will remain from the north-
northeast with gusts of 20 to 30 kts after 0900 UTC. Sleet and
snow will change over to all snow around 1400-1500 UTC. Light snow
will end during the mid to late afternoon hours.

Przybylinski

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     28  32  18  41 /  80  80  10   5
Quincy          24  31  16  41 /  60  30  10   5
Columbia        27  32  17  44 /  90  80  10   5
Jefferson City  29  33  17  45 /  90  90  10   5
Salem           30  33  20  41 /  70  90  20   5
Farmington      33  34  18  42 / 100 100  20   5

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 4 AM to 7 PM CDT Sunday FOR
     Crawford MO-Franklin MO-Gasconade MO-Iron MO-Jefferson MO-
     Madison MO-Osage MO-Reynolds MO-St. Francois MO-Ste.
     Genevieve MO-Washington MO.

IL...WINTER WEATHER ADVISORY from 4 AM to 7 PM CDT Sunday FOR Clinton
     IL-Marion IL-Monroe IL-Randolph IL-St. Clair IL-Washington
     IL.

&&

$$

WFO LSX