Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 150850
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
350 AM CDT Wed Apr 15 2015

.SHORT TERM: (Today and Tonight)
Issued at 349 AM CDT Wed Apr 15 2015

Cutoff low over the Kansas/Nebraska border will get absorbed into
the mean flow today and the resulting shortwave should pass
northeast over the region today into tonight.  Weak warm advection
will continue above the surface at 850mb and guidance continues to
show weak and transient areas of moisture convergence through the
day and into tonight across the lower Mississippi Valley up toward
the STL Metro.  NSSL and SPC 4km WRF models show some fairly
widespread showers over Arkansas in this region of warm advection,
but the showers tend to break up into scattered and isolated pockets
by the time they reach the eastern Ozarks.  Think this is due to the
drier air continuing to be pumped into the Mid Mississippi Valley by
the high over the Great Lakes and southeast Canada.  As a result,
have kept scattered showers in the forecast across much of the area,
except isolated in north/northeast areas today.  Guidance refocuses
the axis of precipitation further east tonight into the Ohio Valley
but I can`t rule out continuing isolated to widely scattered showers
primarily along and east of the Mississippi.  As mentioned
yesterday, temperatures will be highly dependent on cloud
cover/precip so have stuck pretty close to MOS numbers for highs
today and lows tonight.

Carney

.LONG TERM:  (Wednesday through Next Tuesday)
Issued at 319 PM CDT Tue Apr 14 2015

(Wednesday through Friday)

Main focus thru this period will be RA chances.

Upper low over KS is helping generate RA across KS and into OK. This
low will continue to open and lift nwd thru Wed. Some question as to
how much coverage will be left tomorrow and into the eve hrs. Still
believe coverage will be at least sct across portions of the area.
However, exactly where those areas will be remains somewhat
uncertain.

Focus quickly turns to RA chances on Fri. Mdls continue to differ
greatly with the lee low ejecting into the Plains some time late
this week. The GFS continues faster with a similar soln as
yesterday, which does lend some confidence in it, esp as the GEFS
mean is trending faster than the ECMWF. However, as this is still
soln is still a fast outlier, have trended away from it and twd the
ECMWF. The GEM is even slower than the ECMWF and have largely
ignored this soln.

As for temps, with RA expected tomorrow, have trended twd the cooler
guidance. With less clouds expected Thurs have trended warmer, but
then twd cooler guidance again on Fri with more RA/clouds possible.

(Saturday through Tuesday)

Closed low will try and finally make progress eastward this weekend.
As mentioned above...slower ECMWF/GEM are preferred solutions. Chances
of showers with an embedded thunderstorm or two are possible through
Monday...with the best chance (40-50 PoPs) on Sunday as ECMWF/GEM
solutions eject system out into mid-Mississippi Valley. Behind this
system...cooler and drier weather is expected Monday night and Tuesday
with temperatures dipping back below normal as 850-hPa temps slide
into the single digits above zero Celcius.

Tilly/Gosselin

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1111 PM CDT Tue Apr 14 2015

VFR flight conditions should continue to prevail at the TAF sites
with predominantly mid-high clouds tonight lowering to 4000-8000 ft
on Wednesday. MVFR cigs may move into central and east central MO
after 00z/16th but confidence is not great enough to mention at
this time.

Central MO/KCOU is the only terminal with confidence to mention
any light rain. There might be some additional light rain between
06-08z otherwise the next time frame with potential is roughly
17-21z. Elsewhere some light rain showers may impact the St.
Louis area terminals in the afternoon but confidence is too low to
mention.

Specifics for KSTL:

VFR flight conditions are expected to prevail with predominantly
mid-high clouds tonight lowering to 4000-5000 ft on Wednesday
afternoon. Scattered light rain showers may impact the terminal
on Wedneday afternoon, and MVFR cigs might move into the terminal
after 00z/16th, however confidence is not great enough for either
element to include in the forecast at this time.

Glass

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     69  55  73  57 /  30  30  10  10
Quincy          67  51  71  55 /  20  20  10  10
Columbia        66  52  74  56 /  40  20  10  10
Jefferson City  67  52  74  55 /  40  30  10  10
Salem           68  55  71  55 /  30  40  20  10
Farmington      66  55  72  56 /  40  40  10  10

&&

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

$$

WFO LSX






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