Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 192123
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
323 PM CST Sun Nov 19 2017

.SYNOPSIS...
Issued at 250 PM CST Sun Nov 19 2017

Brisk NW winds in process of diminishing while turning from WSW,
as surface high moves across MO with attendant weak ridge axis
sliding through cwa. These southerly winds spell a warming trend
over the next 24 hours.

&&

.SHORT TERM...(This Evening through Monday)
ISSUED AT 250 PM CST Sun Nov 19 2017

Dry, and not as cool tonight... warmer on Monday. Strengthening
low level southerly winds tonight and attendant warm advection
will limit temp drop tonight, with lows mostly in the upper 20s
to mid 30s beneath some thin high cirrus. Temps will likely
become nearly steady or rise a few degrees later this evening
and overnight with increase in southerly winds and 925 mb temps
climbing into a general range from 4C NE to 9C SW by 12z Monday.

Monday will feature mostly sunny skies, with just some high
mainly thin cloudiness. It will also be breezy with SW winds
10-20+ mph. The combination of the sunshine and gusty SW winds,
and attendant WAA and mixing will boost highs above normal and
into the 50s areawide.

.LONG TERM...(Monday Night through Sunday)
ISSUED AT 250 PM CST Sun Nov 19 2017

Monday night and Tuesday...Mild pre-frontal evening, until strong
cold front plunges through the region from the northwest toward Tue
morning. Most models except the 12z GFS bring the front through dry,
with the GFS breaking out some light QPF acrs the northeastern third
of the CWA toward 12z Tue. With such dry low to mid levels, feel the
front will just generate some AC along it and will maintain a dry
fcst into Tue morning for now. Tue highs will look to occur during
the late morning or midday, before stout llvl cold advection
produces a temp drop off during the afternoon...more noticeable in
the southern third of the CWA where temps may hit the mid to upper
40s before falling off later in the afternoon. the big weather
factor of the day will be the brisk northwest winds in incoming
Canadian ridge gradient. Current fcst soundings and mixing profiles
in cold air advection regime suggest enough downward momentum
transfer for sustained sfc winds of 20 to near 30 MPH, and gusts to
at least 40 MPH...not all that far off wind advisory levels. Cold
night under sfc ridge Tue night, with a sfc wind decouple allowing
for widespread lows in the teens to low 20s.

Wednesday and Thursday...Chilly day Wed in the 30s under passing
ridge axis, with late day and especially into Wed night increasing
return flow ahead of the next wave making for non-diurnal temp
trends again...lows in the 20s Wed evening before steady to slow
rise into Thu morning. Some signs in the latest medium range model
runs of a clipper-like warm air advection wing producing light
elevated precip close to the area or even skirting the northern CWA
late Wed night, but again will maintain a dry fcst with dry low to
mid levels in mind and limited moisture return source evident at
this point. probably just some AC/mid and high cloud generation and
virga acrs southern WI. Weak frontal passage early Thu, with ongoing
west to northwest flow actually warm air advecting/moderating the
thermal column in place to help temps make it well up in the 40s for
Turkey Day...a 50 possible in the south.

Friday through next Sunday...longer range trends suggest active/
progressive pattern to shuttle a much stronger upper low out of
western Canada and to the northern GRT LKS by Sat morning. The local
area to be bathed in this system`s increasing warm draw as Friday
progresses and increasing breezy south-southwest sfc winds. Current
thickness improvement from the south/LLVL temp advection indicated by
the 12z GFS and especially the ECMWF that even with marginal
mixing, temps will be well up in the 50s and even some 60s possible.
These mild temps possible as long as there is some sunshine.
Although mid to high cloud thickening looks possible during the
afternoon ahead of the incoming frontal system. Will trend Friday
highs up some for now, but still not near the potentail indicated by
today`s medium range model runs. As the deepening low digs into the
northern GRT LKS Fri night, there may be a better moisture feed and
convergence to generate at least some light rain or showers near or
in the northern CWA Fri evening. Much better support for measurable
precip will look to occur to the north acrs MN into WI near synoptic
scale lift machine. Increasing northwest winds, cooler conditions
and mainly a dry post-frontal day to characterize Saturday, with
continuing cold flux into Sunday with influence if northern plains
into upper MS RVR valley ridging.    ..12..

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
ISSUED AT 1021 AM CST Sun Nov 19 2017

VFR conditions expected to persist through the TAF cycle. W/NW
winds will be above 10 kts today and gusty at times. Tonight,
winds will shift from the SSW around 10 kts then become gusty at
times at 10-20 kts on Monday.

&&

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

$$

SYNOPSIS...McClure
SHORT TERM...McClure
LONG TERM...12
AVIATION...McClure



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