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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
611 am CST Tuesday Feb 9 2016

..aviation update...

Synopsis...
issued at 319 am CST Tuesday Feb 9 2016

Light snow and flurries continued overnight across the area...with
many locations picking up a dusting of fluffy snow. A northwest
wind gusting over 20 miles per hour resulted in some shallow blowing and
drifting snow. Early morning temperatures were in the teens area-
wide.

&&

Short term...(today and tonight)
issued at 319 am CST Tuesday Feb 9 2016

The main issues in the short term period are the lingering light
snow early...then the potential for near advisory criteria wind
chill values tonight.

In the near term...the light...fluffy nature of the snow and the
lingering brisk northwest wind are producing some shallow blowing
and drifting snow. Have handled this issue with a Special Weather
Statement. High resolution models are in agreement in rapidly
shutting down the forcing after 12z this morning. Expect light
snow/flurries to taper off from west to east through the
day...with an additional light dusting possible mainly in western
Illinois. Afternoon highs are only expected to rebound a few
degrees...generally reaching the 10 to 20 degree range.

For tonight...high pressure will begin to build in from the
west...but the northwest wind is expected to stay up above 10 miles per hour.
Temperatures in the single digits above and below zero will result in
wind chill values of 10 to 20 below zero late tonight into early
Wednesday morning. The Highway 20 corridor will be near advisory
criteria...something for later shifts to evaluate for potential
headlines.

Long term...(wednesday through monday)
issued at 319 am CST Tuesday Feb 9 2016

Wednesday...cold...highs in the teens to upper single digits...
approximately 20 degrees below average for the middle of
February. All models paint light quantitative precipitation forecast across the southwest half of
the dvn County Warning Area as a clipper system quickly exits northern Alberta
Tuesday evening...then reaches the upper Mississippi Valley by
Wednesday afternoon or evening into Wednesday night. Consensus is to
keep the highest quantitative precipitation forecast values and snowfall amounts over the far
southwest and southern portions of the County Warning Area. The track and exact
timing of this system will likely fluctuate some yet.

As it stands now...the counties along a line from Cedar Rapids to
the quadrant cities would be on the extreme northern/eastern edge of
the light snow shield therefore receiving little to no
accumulation. Further to the southwest...snowfall up to 1 inch is
possible with quantitative precipitation forecast near 0.05 hundredths or slightly higher. Forecast
soundings are too warm for high snow ratios...12-to-1 seems
reasonable.

Single digit lows are forecast at night for most of the County Warning Area. A
little colder across the far north near to a few degrees below
zero.

Thursday...quiet and continued cold. Teens north of I-80...20s to
the south. Dry weather is anticipated along with partly to mostly
sunny skies.

Friday...temperatures moderate a bit into the lower 20s far
north...middle 20s along I-80...and lower 30s far South. West-northwest winds
warm 850mb temperatures but only to between -8 c to -12 c.

Light snow chances return to the forecast area. The northwest flow aloft
will bring another Alberta clipper southeastward into the Midwest.
Highest probability of precipitation are Friday morning into the afternoon between 20-40
percent. Again any snow accumulations should remain light because
similar to the Wednesday clipper this system looks rather weak.
Current forecast quantitative precipitation forecast is at 0.05 inches or less.

Saturday...strong 1045-1048 high builds into the upper
Midwest...advecting colder temperatures into east Iowa/west Illinois/and NE
Missouri. For this reason...lower single digits above and below
zero are forecast Friday night into Saturday morning...creating
wind chills in the teens below zero...but in the lower to middle
20s below zero along and north of a Cedar Rapids to Galena line. A
Wind Chill Advisory may be necessary for parts of the County Warning Area.

850mb temperatures will fall down to near -18 c. Current forecast high
temperatures are about 20 degrees below seasonal normals...upper teens
far south...middle teens along I-80...and upper single digits over
the northwest.

Sunday...SW return flow results in low-level warm air and moisture
advection and chances for precipitation. European model (ecmwf) suggests cold enough
thermal profiles for mostly snow...GFS is a little warmer...cannot
get too much into the details yet. Uttech

&&

Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 606 am CST Tuesday Feb 9 2016

Expect lingering show showers/flurries...mainly this
morning...with MVFR conditions. Have pushed back the clearing
trend at kcid/kdbq to late afternoon and tonight. Gusts between
24-29kts expected by late morning.

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

Synopsis...rp Kinney
short term...rp Kinney
long term...uttech
aviation...rp Kinney

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