Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 200917
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
314 AM CST Tue Feb 20 2018


.SYNOPSIS...
Issued at 304 AM CST Tue Feb 20 2018

An area of rain and embedded storms is moving across the outlook
area at 3 AM CST. Some freezing rain is noted just to the west of
the region. Trends suggest some freezing may impact western few to
several counties this morning before ending. Radar trends suggest
SE portions of the area may receive another .5 inch or more of
rain before ending late today.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 304 AM CST Tue Feb 20 2018

Short term forecast confidence assessment...fair to poor with
timing and coverage of precipitation today. Ice chances rising in
far NW counties this morning main concern.

Today...categorical pops ending NW to SE this PM with some ice far
NW counties. High nearly steady to falling east by PM as cold air
moves in. No water issues noted yet though some rivers are approaching
bankfull at 3 AM. Highs lower 30s NW to mid/upper 50s east.

Tonight...precipitation should move east by midnight with clearing
skies toward morning. Minor accumulations of mostly rain with some
mixed precipitation far SE this evening. Mins teens NW to lower
20s SE sections.

.LONG TERM...(Wednesday through Monday)
ISSUED AT 304 AM CST Tue Feb 20 2018

The longwave trof has retrogressed to the west coast which is its
normal climatological position. Southwest flow aloft means that an
active weather pattern will continue for the Midwest through the end
of the month.

Quiet, dry, and much colder conditions will be seen across the area
on Wednesday. Temperatures will average below normal. Attention then
turns to the next two storm systems.

Wednesday night through Thursday night two separate systems will
move through the area. For the first system, the atmosphere will
need to saturate. Saturating the atmosphere will drop temperatures
below freezing so the precipitation will initially start out as snow
late Wednesday night.

As temperatures warm on Thursday the snow will change over to rain.
During the transition period some sleet and freezing rain will be
possible.

Thursday night could be very interesting with the second system.

There are differences among the models regarding the track of the
second system. Track will be very important in regards to
precipitation type. As the atmosphere cools Thursday night, sleet
and freezing rain will mix back in with the rain along with some
snow. Right now the potential is there for an ice event across much
of the area.

Friday on...

Sleet and freezing rain will change back over to all rain on Friday
and end as the atmosphere warms. Temperatures will average above
normal.

Friday night through Saturday night another one or two systems will
move through the Midwest. Again, the track of each system will
determine precipitation type. Right now the model consensus has
chance to likely pops from Friday night through Saturday night.

Sunday/Sunday night the model consensus has dry conditions for the
area as high pressure moves through the Midwest.

On Monday, the next storm system begins moving into the Midwest. The
models are highly varied on the track and timing of this storm
system. As a result of these differences, the model consensus has
slight chance pops for roughly the southern half of the area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
ISSUED AT 1125 PM CST Mon Feb 19 2018

Widespread showers and isolated storms will continue to impact
KBRL/KMLI overnight, and will eventually spread into KCID/KDBQ.
Convergence area has lifted north and the potential for dense fog
impacting TAF sites is now low. There will likely be a break in
the rain after 12z, before more rain by mid to late morning, then
ending during the afternoon from west to east.


&&

.HYDROLOGY...
Issued at 304 AM CST Tue Feb 20 2018

River flood watches remain in effect for the Rock and Green rivers.

The initial round of rain has some rivers responding across eastern
Iowa and northern Illinois while others have not.

Across Illinois rainfall over the next 24 hours may be 0.5 to 1.5
inches on top of frozen ground. Depending upon how much rain occurs
across the Rock and Green river basins, moderate flooding may occur
at Joslin and Moline and minor flooding may occur at Como and
Geneseo. These forecasts may change depending upon the timing and
overall rainfall amounts. Please see the latest river forecasts and
watches for the most up to date information.

Much smaller streams and creeks may also flood depending upon how
much rain falls over the next 24 hours.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory until noon CST today for Benton-Buchanan-
     Delaware.
IL...NONE.
MO...NONE.

&&

$$

SYNOPSIS...16
SHORT TERM...16
LONG TERM...08
AVIATION...RP Kinney
HYDROLOGY...08


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