Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 142022
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
322 PM CDT Tue Apr 14 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 319 PM CDT Tue Apr 14 2015

May have a few sprinkles early this evening from mid level clouds,
but the better potential for measurable rain should hold off until
later this evening and overnight as the upper level trough with
embedded shortwaves moves from the southern Plains northeastward
into MO by 12Z Wednesday.  As the low level winds veer around to a
southeasterly direction low level moisture will spread back
northward into MO, mainly west of the Mississippi River on the
southwestern periphery of the 850 mb ridge.  Showers should move
into portions of southeast and central MO later this evening, then
shift northward into portions of northeast MO towards morning.  With
more mid level moisture and cloudiness moving back into our forecast
area went on the warmer side of the MOS guidance for low
temperatures tonight.

GKS

.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 18z TAFs through 18z Wednesday Afternoon)
Issued at 1052 AM CDT Tue Apr 14 2015

Mid level clouds may scatter out this afternoon, but will return
tonight as an upper level disturbance over the southern Plains
moves northeastward into the area. The cloud ceiling will
gradually lower tonight and Wednesday as low level moisture
returns to the area with the ceiling possibly dropping into the
MVFR catagory in COU Wednesday morning and in STL Wednesday
afternoon. Showers may return to COU late tonight and Wednesday
morning and to STL Wednesday afternoon as the surface ridge now
centered over northeastern IA shifts well northeast of the area and a
warm front well south of the taf sites begins to shift back
northward. E-nely surface wind will veer around to a more due ely
direction on Wednesday.

Specifics for KSTL: Just mid-high level clouds this afternoon,
then the cloud ceiling will gradually lower tonight and Wednesday,
possibly dropping into the MVFR catagory Wednesday afternoon.
There may also be some showers Wednesday afternoon as the low
levels eventually saturate. Nely surface wind will veer around to
an ely direction late tonight.

GKS

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     49  67  55  75 /  20  40  40  10
Quincy          46  64  51  73 /  20  30  20  10
Columbia        49  64  51  75 /  40  40  20  10
Jefferson City  49  65  51  76 /  40  40  20  10
Salem           48  66  54  72 /  20  20  30  20
Farmington      48  64  54  73 /  30  40  40  10

&&

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

$$

WFO LSX






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