Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 211728

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1228 PM CDT Sun May 21 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 305 AM CDT Sun May 21 2017

Surface ridge continues to build into the region. So will see dry
and cooler conditions for today with some wrap around strato cu
possible for portions of northeast MO and west central Illinois this
afternoon. Otherwise, highs will be in the mid 60s to low 70s.

Surface ridge will remain over region tonight with clear skies and
light winds, so will see lows in the upper 40s to low 50s, about 5
to 10 degrees below normal.


.LONG TERM...  (Monday through Saturday)
Issued at 305 AM CDT Sun May 21 2017

Overall, mdls are in good agreement thru the short term. Period will
begin with a nearly stacked upper low just NW of Lake Superior. This
low will keep the region under cyclonic flow thru Thurs before
heights begin to rise again.

A leading s/w is still progd to bring a chance of precip to nrn
portions of the CWA late Mon morning, before another trof rotates
around the low bringing a reinforcing cdfnt thru the region and more
rain. The upper low is progd to sink swd by mid week, then moving
ewd out of the area with the sfc ridge building into the area on
Thurs. This will allow for a dry period in the forecast, albeit
brief. The chance of TSRA returns as the wrmfnt lifts nwd on Fri and
continues into next weekend.

Given the persistent cyclonic flow, have trended temp twd the cooler
guidance thru mid week. The exception is Mon and have trended warmer
with more insolation expected, except for nrn portions of the CWA
where precip is possible sooner. Temps return to more seasonal avg
on Fri as the wrmfnt lifts nwd thru the region.



.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1222 PM CDT Sun May 21 2017

VFR conditions likely through the period as an area of high
pressure across northeastern Oklahoma slowly moves to the
east/northeast through the period. Stratocumulus will affect KUIN
through mid afternoon but broken cloud deck should stay VFR after
briefly dipping down into MVFR earlier this morning. FEW-SCT
stratocu also likely at metro terminals this afternoon. Mostly
clear tonight with light winds. Winds become south/southwesterly
during the day on Monday along with increasing midlevel cloudiness
from the west ahead of next system.


FEW-SCT stratocu with bases around 4000 feet AGL this afternoon.
Mostly clear with light winds tonight, becoming south/southwest
during the day on Monday. Continued dry but increasing midlevel
clouds late on Monday ahead of next weather system.





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