Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 021800

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
100 PM CDT MON MAY 2 2016

.SHORT TERM...  (Through Late This Afternoon)
Issued at 315 AM CDT Mon May 2 2016

Complex and messy upper air pattern remains across the region this
morning. Leading s/w continues to approach the region early this
morning and is responsible for light RA across swrn into central MO.
This area of precip shud continue to move newd thru the area this
morning. Mdls suggest it will dissipate as it moves into the CWA
around sunrise. While this is possible due to the better low level
moisture convergence pushes S of the area, believe the leading s/w
will be sufficient to maintain higher PoPs thru mid-morning.

For the remainder of the day, have kept PoPs in the slight chance
range for now as isod to widely sct SHRA are expected today.
However, coverage may be somewhat higher across nrn half to third
of the CWA as the upper trof pulls newd thru the area today. The
bulk of these SHRA will be diurnally driven and shud dissipate
this evening.

As for temps today, with extensive cloud cover in place, and with
the trof in place today, do not expect much clearing today except
for the srn third or so of the CWA. Where breaks to occur this
morning, believe CU will develop, filling them in. This complicates
the temps forecast for today as a strong May sun can help temps jump
even with a short period of insolation. Still, believe clouds will
be the rule for today and have trended temps aob the cooler guidance
for much of the CWA. The exception will be the srn portions where
more insolation is expected. This same area is also along and S of
the 850mb fnt, which shud help warm temps today.


.LONG TERM...  (Tonight through Sunday)
Issued at 315 AM CDT Mon May 2 2016

Will see some lingering isolated/scattered showers this evening
in cyclonic flow on back side of system. The activity will
gradually taper off. Otherwise, clouds to slowly thin out from
north to south overnight and lows will be in the 40s, a bit below
normal for this time of year.

Because of the lingering cyclonic flow, could still see some
isolated showers in the far eastern portions of forecast area on
Tuesday. However, most locations to remain dry with partly sunny
skies and highs in the mid to upper 60s.

Then Tuesday night, a more vigorous trof/secondary cold front
associated with surface low anchored over the Great Lakes region to
slide south through area. So increased pops with scattered showers
for portions of west central/southwest IL Tuesday night through
Wednesday, as main energy to remain to our northeast and east.

For rest of work week, will see dry conditions with temperatures
slowly moderating. By Friday highs will be in the low to mid 70s and
in the upper 70s to low 80s on Saturday.  Then next significant
weather system to approach region Saturday night and Sunday with
increasing chances of showers and thunderstorms through the rest
of the weekend.



.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1222 PM CDT Mon May 2 2016

Specifics for KCOU, KUIN: MVFR cigs are expected at KUIN/KCOU
through the afternoon before cigs rise to to low-end VFR and
remain there for the rest of the pd. Winds remain either lgt/var
or northwesterly and light.

Specifics for KSTL, KSUS, KCPS: Brief pds of MVFR cigs are
possible for the next hour or two. Cigs should remain
predominantly low-end VFR for most of the TAF pd. Winds remain
either lgt/var or northwesterly and light.





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