Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 262056

Area Forecast Discussion
National Weather Service Saint Louis MO
353 PM CDT Wed Oct 26 2016

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 340 PM CDT Wed Oct 26 2016

Mesoscale vort center which has triggered showers and isolated
thunderstorms this afternoon will move east of the CWA by around 00Z
ending the threat of additional storms. Behind that feature...a cold
front will move through the CWA during the evening and reach the St.
Louis metro by around 06Z. There may be a few light showers along
the front...however insufficient CAPE should preclude additional
thunder. Winds will become northwest behind the front with a low
stratus deck moving in as well. Stratus will gradually clear from
west to east during the late morning and afternoon on Thursday.
Temperatures will be near seasonal normals on Thursday...with highs
in the low to mid 60s.


.LONG TERM...  (Thursday Night through Next Wednesday)
Issued at 340 PM CDT Wed Oct 26 2016

The current weather pattern indicates a warm and dry fcst thru early
next week.

Thursday night thru Friday

SW upper flow in place Thu night gradually becomes zonal Fri as a
chunk of energy is ejected from the West Coast trough. The short wave
comes onshore across the Pac NW Thu PM and then traverses the
US/Canadian border Fri. At the SFC...SFC ridge is already E of the
CWA by Thu night allowing return flow to be well established on Fri.
Thu night should be seasonable warm with lows temps 5-10 degrees
above avg due to a mild air mass in place and the sthrly flow. This
will set the stage for a warm Fri. Deep S/SW flow and 850 temps in
the mid/upper teens are basic ingredients to a warm day but the key
is how deep mixing will be. The NAM/Local WRF and SREF all indicate
mixing heights sloping from approx 925mb across sthrn IL to 875mb
across cntrl MO...but the GFS is considerably higher except across
sthrn IL. This should lead to highs ranging from near 70 for sthrn IL
to low and potentially mid 80s for cntrl MO. Another short wave is
kicked out of the base of the West Coast trough Fri.

Friday night thru Sunday night

Sthrly flow will keep up Fri night as the initial short wave slides
SE into the Grt Lks. This feature will drag a cold front into the
nthrn FA Sat mrng. Since the short wave is fcst to pass well N of
the FA...the bndry doesn`t have a whole lot of drive to push it S so
it is expected to slowly sinks S thru the day reaching along or just
N of I70 by Sat night. FROPA appears to be dry attm. The next short
wave approaches the region late Sat night into Sun mrng. The vort
assocd with this feature generates a bit of precip but the bulk of
this activity remains NE of the CWA as the short wave passes by.
This feature helps push the bndry a little farther S by Sun
evng...taking it S of the MO Rvr. The bulk of the West Coast trough
comes onshore a result... upper level ridging begins to
work into the area Sun PM. Solutions for the wknd have shifted
considerably over the past several days so I would think there will
continue to be addtnl adjustments as guidance tries to fine tune the

Sat should be another warm day...esp for locations that remain S of
the bndry thru a good portion of the aftn. 850mb temps remain in the
mid/upper teens and would expect maybe even a little better
mixing out ahead of the advancing cold front which should lead to
another day with widespread 70s with a few lower 80s. Even with a
bndry that is expected to be S of the majority of the CWA by Sun
aftn...Sun is expected to be another day with above avg temps with
highs in the upper 60s to mid 70s from N to the same time
being possibly the coolest day thru the middle of next week.

Monday thru Wed

Upper flow turns SWrly in advance of the main short wave. The wknd
cold front will lift back north as a warm from reestablishing deep
sthrly flow thru the day setting the stage for yet another day with
much above normal temps. 850mb temps are once again in the mid/upper
teens...though the 850 thermal ridge is centered N of the FA. The GFS
and ECMWF have timing differences with the main short wave energy.
The GFS is about 6-12 hrs faster than the ECMWF. The GFS drags a
cold front thru the CWA Mon night whereas the ECMWF has the cold
front entering the nthrn CWA Tue mrng. The ECMWF solution stalls the
bndry approx along I70 Tue PM and then washes the front out
overnight. Regardless of the would appear that the
pattern of dry FROPAs will continue. Depending on the eventual
timing of the Tue cold front...Tue could be another warm day for at
least a portion of the area.  A SFC ridge passes N of the area Tue
into Wed allowing return flow to begin again by late Tue night. Wed
could very well be yet another day of aoa normal temps.



.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 100 PM CDT Wed Oct 26 2016

Narrow band of showers and embedded thunderstorms ahead of an
upper level disturbance will move east of KSTL metro TAF sites by
around 19Z. Some light rain showers will continue to be possible
through around 06Z as a cold front approaches the area. Winds will
become northwest behind the front. MVFR ceilings will move into
KUIN and KCOU by around 20Z and to KSTL metro sites by 01Z. Very
large area of post frontal low end MVFR and IFR ceilings over
Iowa will continue to surge southward overnight. Have included
tempo groups at KUIN and KSTL area TAF sites to account for the
possibility of IFR ceilings overnight. MVFR ceilings will
gradually clear out from west to east on Thursday afternoon.




Issued at 340 PM CDT Wed Oct 26 2016

With an upcoming stretch of unseasonable warmth expected over the
weekend, here is a list of record high temperatures thru the weekend.
Although there are no record high temperatures in the forecast just
yet, stay tuned to the forecast as that could change over the next
several days.

     STL    COU     UIN
Fri10/28 85/1927 85/1927 85/1927



Saint Louis     50  64  52  81 /  50   0   0   0
Quincy          47  61  50  77 /  30   0   0   0
Columbia        48  66  52  80 /  30   0   0   0
Jefferson City  49  67  52  81 /  30   0   0   0
Salem           51  61  47  75 /  60   0   0   0
Farmington      53  67  49  76 /  50   0   0   0




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