Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 160924
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
324 AM CST Mon Dec 16 2013
.SHORT TERM: (Through Tonight)
Issued at 1233 AM CST Mon Dec 16 2013
Clipper continues to move esewd thru the region with the sfc fnt
stretched thru the area near I-70. A lot of uncertainty remains as
to where any fg develops, if any, or if mainly st will develop.
Areas S of the fnt may continue to see enuf mixing to prevent any
fg development despite the additional moisture due to sn melt.
Clouds are expected to linger thru much of the day across the nrn
half of the CWA.
Have trended twd the warmer guidance across the region. May still
need to raise temps across the srn counties as some areas further
SW have already reached the lower to mid 40s.
With mixing expected to continue overnight and at least high
clouds spreading over the region, have trended twd the warmer
guidance thru tonight as well.
.LONG TERM: (Tuesday through Sunday)
Issued at 242 AM CST Mon Dec 16 2013
(Tuesday through Wednesday)
With no precip expected thru this period, focus will be warming
temps. Mdls are in good agreement regarding mass fields. Prev
forecast still appears to be largely on track and have therefore
made only minor changes. In general, continued trend twd warmer
guidance. With strong WAA over the region on Wed, going forecast
may not be warm enuf as thermal ridge pushes thru the region.
Believe mdls are holding on to the snow field too long into the
forecast period. One factor that may hinder this strong warming is
development of fg/st.
(Thursday through Sunday)
Focus quickly turns to the systems to impact the area late this
week and thru the weekend.
Mdls are coming into better agreement, but differences remain that
would be the difference in ra turning to sn or resulting in fzra.
Timing and placement differences exist over the weekend as another
system pulls newd thru the region. The ECMWF brings the sfc low
further nwd suggesting ra, while the GFS keeps the system further S
suggesting mostly a sn event. Due to uncertainty regarding
placement and timing, have kept the going forecast as is except
for changes in POPs to account for at least an agreement or
possibility of precip. Will make adjustments as needed as mdls
come into better agreement.
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1138 PM CST Sun Dec 15 2013
BUFKIT soundings from the RAP still show light winds and a strong
surface-based inversion along with nearly saturated conditions at
the lowest levels. It still looks like a period of IFR to MVFR fog
will develop over the next 6 hours, then lift into stratus during
the morning hours, but confidence remains low with respect to the
timing. Stratus is likely to linger for most of the day due to
poor mixing and low sun angle, especially at KUIN. Conditions
should improve during the day, but fog/stratus is possible again
on Monday night due to the additional moisture provided by melting
Specifics for KSTL: A boundary is wavering back and forth across
KSTL, causing fluctuations in the temperature and dew point, which
in turn is affecting the fog potential. It still looks like a
period of IFR or MVFR fog will develop over the next 6 hours, then
lift into stratus during the morning hours. Confidence in the
timing of fog remains low. Conditions should improve during the
day, however fog/stratus is possible again on Monday night due to
the additional moisture provided by melting snow.
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 42 28 45 29 / 5 0 0 0
Quincy 32 22 38 22 / 5 0 0 0
Columbia 45 27 46 28 / 5 0 0 0
Jefferson City 46 27 48 28 / 5 0 0 0
Salem 40 27 41 26 / 10 0 0 0
Farmington 47 28 48 28 / 5 0 0 0