Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 160009

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
709 PM CDT SAT OCT 15 2016

.SHORT TERM...  (Through Late Sunday Afternoon)
Issued at 349 PM CDT Sat Oct 15 2016


Unseasonably warm conditions with continued light southerly flow is
forecast for tonight. Expect stratus to expand overnight tonight but
mainly affect northern and western sections of the forecast area.
Weak cold front currently across the mid-Missouri Valley will try
and slide southeast toward the bi-state region...but looks to mainly
weaken/wash out. Best upper-level support will reside north of CWA only expecting isolated-scattered showers with a few
rumbles of thunder. Best chances for this activity will be for
portions of northeast Missouri and west-central Illinois.


Any threat for isolated-scattered showers/storms should quickly
lessen toward midday as low-level jet weakens and veers. Similar to
today...expect stratus to lessen in coverage and break up quickly by
late morning leaving at least partial sunshine. Combination of a
warm start to the day and increasing temperatures aloft should yield
highs some 15+ degrees above normal for mid October and could
threaten the record high for the date at KCOU.


.LONG TERM...  (Sunday Night through Next Saturday)
Issued at 349 PM CDT Sat Oct 15 2016

Not a lot of change from the prev forecast. Upper ridge builds into
the area with record temps expected on Mon. Have continued with what
the prev shift had for continuity. However, still concerned that the
region may not mix to 850mb on Mon. Still, given the thermal
profile, temps in the upper 80s wud still be expected. The other
factor to watch on Mon are winds. There are some indications that
gusts near advisory criteria are possible, mainly over wrn and nrn
portions of the CWA. Have kept gusts in the lower 30 kts range, but
will need to continue to watch.

Mdl guidance has changed a bit for the fropa on Tues. Disagreement
continues regarding the approaching of the main trof by mid week.
The GFS/ECMWF/GEM are now in fairly good agreement, which happens to
be more like the GFS soln yesterday. The main difference is timing,
however, due to this, the ECMWF develops a sfc wave as the fnt hangs
up across the CWA.

While differences remain, mdls do agree that at least the srn half
of the CWA shud get rain. Have therefore increased PoPs into the
likely cat. Timing of precip moving out differs and have lower
chances beyond.

With much cooler temps moving in with the sfc ridge, have trended
lower for Fri with continued CAA across the region.



.AVIATION...  (For the 00z TAFs through 00z Sunday Evening)
Issued at 629 PM CDT Sat Oct 15 2016

Low level wind shear is expected tonight as a low level jet sets
up around 2000ft AGL. Scattered showers will also move across
eastern Missouri and western Illinois late tonight and early
Sunday, so have included VCSH or PROB30 groups in the TAFS for
this possibility. Atmosphere is rather dry, so will keep TAFS VFR
for now.

SPECIFICS FOR KSTL: Expect some LLWS overnight as a low level jet
around 2000ft AGL will set up over the area. Some scattered
showers will also move across the region during the early morning
hours on Sunday, so have also included a PROB30 group for that
possibility. Atmosphere is rather dry, so will keep TAFS VFR for



Issued at 343 AM CDT Thu Oct 13 2016

Unseasonably warm conditions are expected to persist through
the weekend and into early next week and may approach record
territory. The following lists record high temperatures and
record high minimum temperatures for St. Louis, Columbia and
Quincy from Sunday to Tuesday.

St. LouisColumbiaQuincy

10/16   High Low:65/196566/196867/1968

10/17High Low:66/199864/196566/1935

Tuesday High:87/195386/195387/1924
10/18High Low:68/198564/197166/1938




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