Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
000
FXUS63 KDVN 052344
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
544 PM CST Tue Dec 5 2017

...00z AVIATION UPDATE...

.SYNOPSIS...
Issued at 325 PM CST Tue Dec 5 2017

At 2 PM CST...cold and blustery conditions prevail with westerly winds
of 25 to 40+ mph and temperatures in the lower to middle 30s with isolated
flurries. Cold and dry conditions to continue with risk of flurries
or possibly very light snow into early next week.

&&

.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 325 PM CST Tue Dec 5 2017

Short term forecast confidence assessment...fair to poor or average
to below average. The primary risk tonight is area mins, especially
northern sections too mild that may be 3 to locally 5 plus degrees.

Tonight...clear to partly cloudy at times with westerly winds decreasing
to 10 to 15 mph. Forecast lows mostly 15 to 25 with concern many locations
that may be too mild if skies clear, especially northern sections. Plan
to cancel 3 SW counties based on decreasing trends, let rest of
counties expire at 6 PM.

Wednesday...mostly sunny with westerly winds of 10 to 20+ mph with some
gusts to around 25 north sections until mid to late PM. Highs again
to be below normal, upper 20s north to middle/upper 30s south.

.LONG TERM...(Wednesday Night through next Tuesday)
ISSUED AT 325 PM CST Tue Dec 5 2017

Wednesday night and Thursday...Another bout of cold air advection
with an upper level trof dropping in over head, may wring out a few
flurries out of associated incoming stratocu deck into the northern
CWA later Wed night into early Thu morning. For now will limit this
activity down to the Hwy 30 corridor at most after Midnight, but may
have to be expanded to the eastern I80 corridor by early Thu
morning. Lows in the teens. Clouds should clear as Thu progresses,
but even afternoon sunshine won`t help most temps climb out of the
20s for afternoon highs with lingering H85 MB cold pool overhead.
Quick temp crash expected after sunset Thu evening for 12 hr lows
during the evening, before digging clipper system/upper trof into
the northwestern GRT LKS induces southwesterly sfc return flow for
non-diurnal temp trends into early Fri morning.

Friday...In general, the latest run medium range solutions have
trended drier and further northeast with clipper energy propagating
down the through the GRT LKS, and besides some initial flurries, Fri
may be mainly dry through 00z with pre-wave southwesterly warm draw
helping temps recover back up in the 30s. Both the 12z run GFS and
ECMWF now suggest secondary wave dumping down acrs the region in
amplified northwesterlies aloft may produce the most widespread
snow, albeit light, from midnight into early Sat morning now. The
models keep varying in handling of clipper and energy propagation
processes down acrs the area so snow amounts probably not worth
mentioning, but the new Euro says a dusting to half inch from 06z-
12z Sat, while the 12z GFS says a half inch to a little over an inch
by Sat morning.

Saturday and Sunday...Saturday shaping up to be a chilly blustery
northwest flow day behind what ever system passes by Friday
night...highs in the upper 20s to lower 30s in most areas. Wouldn`t
be surprised if some flurries get wrung out in diurnal CU rows as
the day progresses. Clipper wave train in ongoing northwesterlies to
continue into the GRT LKS for second half of the weekend, with
southwesterly warm draw ahead of these systems producing a warm up
for Sunday...some areas may make it into the upper 30s to lower 40s.

Monday and Tuesday...Clipper strength and associated snow amounts/
placement very inconsistent with the past several medium range model
runs for this period, but the general idea is that at least some
flurries or light snow possible Monday and especially Monday night
ahead of the next projected cold push dumping down out of Canada and
acrs the upper Midwest. Both the latest GFS and ECMWF suggest at
least a portion of -20C cold H85 pool to clip the area by next
Tuesday. If this timing verifies, currently fcst highs and lows for
next Tue will be several degrees too warm. bouts of CAA flurries
also possible into mid week, with the watch on for a stronger
clipper as well by the end of the long range.    ..12..

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 534 PM CST Tue Dec 5 2017

Gusty westerly will diminish to around 10 kts by mid to late evening.
A weak clipper system will spread clouds and some flurries across
the region late this evening and overnight. I have kept ceilings
in VFR category, but there is a low chance of MVFR ceilings per
several obs upstream and some recent guidance. Decreasing clouds
and return of gusty winds from W/NW is on tap for Wednesday in wake
of this clipper.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Wind Advisory until 6 PM CST this evening for Benton-Buchanan-
     Cedar-Clinton-Delaware-Dubuque-Iowa-Jackson-Johnson-Jones-
     Keokuk-Linn-Louisa-Muscatine-Scott-Washington.

IL...Wind Advisory until 6 PM CST this evening for Bureau-Carroll-
     Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-Stephenson-
     Whiteside.

MO...NONE.
&&

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.