Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 022321

621 PM CDT FRI OCT 2 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 318 PM CDT Fri Oct 2 2015

Primary concern for tonight will be the chance for some light or
sprinkles over parts of south central Illinois tonight.  A large
cutoff low centered over northwest Florida is pushing moisture
around its northern periphery from the Ohio Valley back toward the
Mississippi Valley.  Showing some weak 850mb moisture convergence
overnight along with a lobe of vorticity swinging through Illinois
which produces some very light qpf.  MOS PoPs are between 30-50
percent over our south central Illinois counties, which looks a
little high.  Since the models have been pretty consistently
producing chance/slight chance PoPs, I went ahead and added in some
15-30 PoPs.  Temperatures will likely be similar to last night`s
with lows mainly in the mid 40s to low 50s.


.LONG TERM:  (Saturday through Next Friday)
Issued at 341 PM CDT Fri Oct 2 2015

A reasonably high amplitude omega block type pattern is developing
with an upper ridge over the Great Plains and Mississippi Valley
sandwiched between cutoff lows over the southeast and southwest
CONUS.  The southeast low will continue to sling moisture back to
the northwest Saturday and Sunday as it drifts east out to sea.
This will cause a continuing chance of light rain or sprinkles over
parts of Illinois.  Upper level ridging will build slowly over the
area as the omega block shifts eastward.  This will allow
temperatures to warm back above normal in the mid to upper 70s by
next Tuesday.  Medium range guidance is in a little better agreement
today with the block breaking down during the Thur-Fri time-frame.
The GFS is still more progressive and stronger with the next cold
front, moving it through early Friday while the ECMWF keeps it hung
up over northern Missouri until later.  Regardless, chance of
showers continues for late next week with temperatures remaining at
or above normal.



.AVIATION:  (For the 00z TAFs through 00z Saturday Evening)
Issued at 612 PM CDT Fri Oct 2 2015

VFR cloud deck just developed over ern MO/srn IL over the past hr
or so. The nrn fringe of this cloud deck may briefly impact COU
around 02z, but will monitor for now. Otherwise, nely winds will
dissipate slightly this eve compared to today and pick up again
Sat morning after sunrise with gusts around 20 kts. Low-end VFR
cigs will reach STL/SUS/CPS during the pre-dawn hrs, reaching COU
around sunrise. Gusty winds are expected to be slow to diminish
Sat evening.




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