Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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499
FXUS63 KDVN 171723
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1223 PM CDT Tue Oct 17 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 324 AM CDT Tue Oct 17 2017

An area of high level clouds overspread eastern Iowa and northern
Illinois during the overnight hours. A southerly breeze averaged 5
to 10 mph. Early morning temperatures ranged from the upper 40s to
mid 50s.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 324 AM CDT Tue Oct 17 2017

The main forecast issue in the short term period is temperatures.
Warm air advection will continue to pick up today with a southwest
breeze gusting around 20 mph and plenty of sunshine. Have bumped
afternoon highs up slightly, especially west where the warmest
850mb temps will reside. Afternoon highs should reach the upper
60s to low 70s, about 10 degrees above normal for the date.

For tonight, expect a mostly clear sky and a south wind staying up
around 5 to 8 mph. Lows will be in the mid to upper 40s.

.LONG TERM...(Wednesday through Monday)
ISSUED AT 324 AM CDT Tue Oct 17 2017

Wednesday through Friday...Rather breezy mild day Wed ahead of
incoming sfc front squeezed in between ridge centers. Mixing up to
base of H8 MB inversion combined with plenty of insolation make for
widespread highs Wed in the low to mid 70s. Then a dry FROPA lays
through the area Wed night into Thu morning, with weaker sfc wind
flow and mixing expected in the vicinity of this feature for Thu.
With not much in the way of airmass change, highs on Thu may be
similar to Wed or a degree or two cooler due to less mixing depth.
Passing sfc ridge and upstream llvl trof/front organization acrs the
western plains re-invigorates warming southerly return flow by
Friday. Currently projected llvl thermal profiles supports
unseasonably mild highs in the mid to upper 70s for Fri, with an
outside chance at an 80 degree reading somewhere as long as the day
remains sunny.

Saturday through Monday...Latest suite of medium range model runs
still advertise increasing southerly warm moist conveyor up off the
western Gulf and to the leeside of an approaching L/W upper trof
with an associated north-to-south oriented sfc front. This should
bring about the next passing precip event to the area sometime this
weekend, but still within model variances at this point. The general
trend with the 00z runs is a bit more progression with the sfc
front. Both the 00z GFS and ECMWF now break out wings of warm
frontal showers and even some thunder earlier in the day Sat acrs
the CWA, before the main event of frontally scooped up long fetch
conveyor of showers and embedded thunder sweep through later Sat
night into Sunday morning. The slower ECMWF lingers rains well into
Sunday and is less wet, while the more progressive GFS sweeps the
rain east by mid Sunday morning. The GFS is also more bullish with
it`s moisture draw this far north and produces well over an inch of
rain in the south half of the CWA. The ECMWF is more in the way of
0.25 to 0.75 of an inch for the local area with its higher amounts
acrs the western CWA. For now will still target Sat night into early
Sunday as the main precip window with high POPs, but wonder with
amplified upper trof and flanking ridges, if further model runs will
trend slower again.

Post-system cool down then looks on tap for early next week, with
some chance for sctrd instability showers later Monday and in/under
base of deepening cool core upper trof overhead.     ..12..

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
ISSUED AT 1221 PM CDT Tue Oct 17 2017

VFR conditions will be seen through 00z/19 with high pressure over
the Ohio Valley and a storm system in the Plains. After 00z/18
LLWS will develop at all TAF sites.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...12
AVIATION...08



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