Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 180839

Area Forecast Discussion
National Weather Service Quad Cities IA IL
339 AM CDT Wed Oct 18 2017

Issued at 338 AM CDT Wed Oct 18 2017

The sky was clear across the region during the overnight hours. A
south wind averaged 5 to 10 mph. Early morning temperatures were
mainly in the upper 40s to low 50s.


.SHORT TERM...(Today and Tonight)
ISSUED AT 338 AM CDT Wed Oct 18 2017

Quiet weather will continue through the short term period. Some
high clouds will drift across the forecast area today. This may
partially temper the slightly warmer 850mb temps compared to
Tuesday. Nonetheless, favorable SW winds gusting around 25 mph
should boost afternoon highs to near or slightly above Tuesday`s
readings, mainly in the 71 to 75 degree range.

For tonight, a weak boundary will drop southeast through the
forecast area. The wind will become light northwest behind the
front as lows settle into the mid/upper 40s.

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 338 AM CDT Wed Oct 18 2017

Thursday and Friday...Weak and disorganized LLVL flow to become
light southeasterly behind passing ridge by late Thu, will keep the
mild side of temp guidance trend going with highs in the low to mid
70s despite a marginal mixing day. Southerly to southeast return
flow still on track to surge up the MS RVR Valley on Fri ahead of
organizing L/W trof acrs the Rockies. Just marginal mixing up to H9
MB and base of inversion aloft in the projected unseasonable warm
air advection pattern produces widespread highs in the mid to upper
70s, with a few sites possibly hitting 80 degrees. South to
southeasterly sfc winds may become gusty at 20 to 25 MPH by Fri
afternoon. Just above the sfc, fcst sounding indicated low to mid
level flow patterns show 30-40 KT deep uniform southwesterlies for
Fri night, but sub-H5 MB layers stay dry into early Sat morning.
Thus for now don`t really buy the idea that a few model solutions
that are breaking out late night WAA type showers acrs the area. But
as a pre-caution will have slight chance POPs in the west after
midnight...may just be elevated sprinkles at best. mild overnight
lows Fri night well up in the 50s with winds and thickening mid/high

Saturday and Sunday...Taking into account low to mid level air
column saturation still to take place, prefer the 00z run ECMWF
solution during the day Saturday of just suggesting spotty light
elevated showers and sprinkles skirting up acrs the area on a still
breezy and seasonably mild day. This opposed to the wetter GFS which
breaks out more substantial showers producing a quarter to half inch
of rain by Sat evening along WAA convergent wings mainly acrs the
southwestern half of the DVN CWA. Warm moist conveyor up off the
western gulf and feeding up to the lee of incoming NNE-to-SSW frontal
complex and approaching upper trof axis, still lon track to make for
a rain event generally Sat night into Sunday morning progression
acrs the region from west-to-east. Mainly an along and post-frontal
precip shield with some embedded thunder. Again, the 00z GFS is
bullish on PWAT feed and northward transport...fueling widespread
rainfall amounts of three quarters of an inch, to near 2 inches by
the time it sweeps east of the area Sunday morning. The 00z Euro
says 0.25 to a few areas in the southwest getting eight tenths of an
inch. It may be more in the middle, most of the area getting
anywhere from a half inch to around around an inch. cooler and
breezy post-frontal Sunday afternoon, but should be at least dry.

Monday and Tuesday...Post-system cool down then looks on tap for
early to mid next week, but developing model descrepancies i n
deepening phase of upper trof overhead and embedded clipper wave
timing. The GFS less amplified on Monday and actually pre-system warm
advects again for temps well up in the 60s, while more amplified 00z
ECMWF continues cooling and has cool core instability showers
streaming acrs much of the CWA Mon afternoon and evening. But
southward plunging upper jet patterns by both models suggest
eventual deep upper trof amplification and a cool down later Mon
through next Wed. Highs only in the 50s by Tue, and any overnight
cloud/wind decrease may allow for overnight lows well down in the
30s by next Tue night.      ..12..


.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
ISSUED AT 1138 PM CDT Tue Oct 17 2017

Southwest winds around 30 to 35 knots at 1200 ft agl above light
south winds at the surface will result in low level wind shear
conditions through the rest of tonight at CID and DBQ. Conditions
will be more marginal at BRL and MLI, where LLWS was not included
in the forecast. Otherwise, conditions will remain VFR overnight
through Wednesday with south winds becoming gusty during the
afternoon hours.




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