Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 182317

617 PM CDT Sat Oct 18 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 318 PM CDT Sat Oct 18 2014


Main concern is the potential for some patchy frost tonight.  Low
clouds were found across the northern and eastern parts of the CWA
this afternoon.  Expect these clouds to clear out early this evening
as with the loss of daytime heating at the same time drier begins to
move into the area from the north.  Temperatures have not climbed as
high as they otherwise could have where the clouds have been today.
However there has also not been much mixing in these areas either
which did not lower the dewpoints.  Still think that we should see
some of the lower dewpoints currently over Iowa advect into the area
tonight.  Skies will clear this evening and winds will turn light as
surface ridge moves across the area.  Have lowered temperatures a
degree or two below MOS guidance where the surface ridge will be at
12Z.  Have also added some patchy frost given the expected mid 30
lows, light winds and clear skies.


.LONG TERM:  (Sunday through Next Saturday)
Issued at 318 PM CDT Sat Oct 18 2014

(Sunday through Tuesday)

Still expect this to be mainly a dry forecast except for Sunday
night and Monday when a passing upper trough and attendant cold
front will bring a chance for isolated/scattered showers.  Still
have best chances from the St. Louis east and south based on the
consistent GFS/ECWMF solutions.  Do not expect as many clouds
tomorrow with highs in the 60s.  Temperatures by Monday will finally
return to the upper 60s and lower 70s.

(Wednesday through Saturday)

Expect continued dry weather during this period.  Both the ECMWF and
the GFS have an upper ridge over Missouri and Illinois as an upper
low sinks southeastward from the central Rockies into Texas.
Meanwhile the large east coast upper low will lift northeastward.
This pattern favors subsidence over our area.  Temperatures will be
close to seasonal normals with forecast soundings showing mixing
only to 900mb with temperatures in the 10-15C range at this level
through the period.



.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 611 PM CDT Sat Oct 18 2014

Winds will diminish quickly with sunset becoming light and vrb at
most locations. With light winds, frost will be possible at
terminals. Light FG will also be possible, but most likely
locations are SUS/CPS, but impacts are expected to be brief.
Otherwise, winds will become sly to sswly late Sun morning and
remain light.

Specifics for KSTL: VFR and dry thru the period. Winds will
diminish quickly with sunset. Frost will be possible late tonight.
Winds will become sly late Sun morning and remain light.





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