Wind Chill Advisory 9, NWS Quad Cities, IA

Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Washington County, IA, Bureau County, IL, Carroll County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, McDonough County, IL, Mercer County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL

Area Forecast Discussion
National Weather Service Quad Cities IA IL
229 PM CST Fri Dec 23 2022

...HYDROLOGY UPDATE...

.SYNOPSIS...
Issued at 138 PM CST Fri Dec 23 2022

The ongoing winter storm/blizzard is continuing, especially along
and north of Interstate 80 in Iowa and Illinois. Mixing depth has
increased a bit diurnally, resulting in a afternoon wind max over
the CWA. Frequent gusts to 40 mph are occurring with some 50 mph
gusts at times. Sustained winds of 25 to 35 are over the north
1/2, while the south is a bit lower, at 15 to 20 mph. Roads
reports show generally blown clear concrete on highways, but
patchy drifts over the road.

The visibility is variable, but has shown frequent 1/4 to 1/2 mile
obs over the north 1/2 of the area, primarily in Iowa, where the
blizzard warning remains in effect. Looking out the window, the
peak gusts are containing instantaneous white outs, while the
steady condition is above that level. The worst conditions are
visible on satellite, with convect roll streamers of blowing snow
showing up, again, mainly over the central and northern CWA.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 138 PM CST Fri Dec 23 2022

Headline Changes:

Will be changing our southern areas to a Wind Chill Warning for
tonight, as the DOT, and available cams show little in the way of
blowing snow there. Otherwise, the winter storm warning and
blizzard warning will remain in effect through 6 AM Saturday.

Forecast:

Winds will remain the main driver of weather through Saturday, as
a gradual decrease occurs. Tonight, we'll still be in the peak
gradient and should see occasional gusts to 45 mph through the
evening, and to 40 mph overnight. It's hard to get a sense how
long the snow will blow significantly, and while conditions may
improve considerably overnight, I'd rather keep the headlines
going.

Lows tonight, will see little if any fall, in a well mixed
boundary layer. Lows around -7 below northwest to -2 southeast are
expected.

Saturday's highs, should reach the single digits north to lower
teens south. Wind chills may require and advisory into the day,
once the winter wx headlines are expired. Our current forecast has
-15 to -25 lasting through Noon.

.LONG TERM...(Saturday night through Friday)
Issued at 138 PM CST Fri Dec 23 2022

Saturday night, Wind chills may once again reach headline levels,
and advisory for -20 to -28 seems needed.

Christmas Day, quiet weather will be in place through the day,
with a flat ridge of high pressure moving through. While winds
will be far from calm, the 8 to 15 mph winds will certainly feel
quieter than it's been.

Sunday night, a clipper is set to move through the region. The 12Z
guidance suggests a favorable track for accumulating snow to move
through the entire CWA, with a typical warm advection wing of
snow. Ratios of 15-20:1 may result in an advisory snow event. For
now, it looks like this fluffy snow will occur without much wind,
but we'll keep an eye on that.

Monday, we'll see the snow end in the morning, with clear skies by
evening. A cold night is in store, and guidance suggests lows in
the zero to -7 range, which could be a bit too mild if the snow
verifies as expected.

The warm up is on the way!

Tuesday south winds return to the region, and will likely be our
last cold day, as highs reach the lower to mid 20s. Aloft, a deep
western trof is expected to form, and last into next week. The
result will be a sustained mild pattern, and eventually, increased
moisture and rain chances. Highs in the 40s and eventually lower
50s seem possible within this pattern, and without a deep snow
pack over the region yet, that seems quite possible.

ERVIN

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1116 AM CST Fri Dec 23 2022

Blowing snow continues to produce variable IFR/LIFR to occasional
MVFR/VFR with cigs and visibility through tonight, mainly along
and north of Interstate 80. Conditions will slowly improve in
general as we move through the late night and morning hours
Saturday. Winds will continue at 25kts to 40 kts through tonight,
then decrease to 15 to 33 kts Saturday.

&&

.HYDROLOGY...
Issued at 138 PM CST Fri Dec 23 2022

Arctic air is forming ice rapidly on all area rivers. Ice impacts
are resulting in bad gage data at Joslin IL on the Rock, and the
Rock Island IL gage on the Mississippi. These problems will likely
not be resolved until tomorrow given the ongoing winter storm.

Some partial ice jams are restricting flow on the Mississippi
River, especially just upstream of Keithsburg IL. Some rises are
expected, but nothing near action or flood stage.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Blizzard Warning until 6 AM CST Saturday for Benton-Buchanan-
     Cedar-Clinton-Delaware-Dubuque-Iowa-Jackson-Johnson-Jones-
     Linn.

     Winter Storm Warning until 6 AM CST Saturday for Des Moines-
     Henry IA-Jefferson-Keokuk-Louisa-Muscatine-Scott-Washington.

     Wind Chill Warning until 6 AM CST Saturday for Lee-Van Buren.

IL...Winter Storm Warning until 6 AM CST Saturday for Bureau-Carroll-
     Henderson-Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-
     Stephenson-Warren-Whiteside.

     Wind Chill Warning until 6 AM CST Saturday for Hancock-McDonough.

MO...Wind Chill Warning until 6 AM CST Saturday for Clark-Scotland.

&&

SYNOPSIS...Ervin
SHORT TERM...Ervin
LONG TERM...Ervin
AVIATION...Ervin
HYDROLOGY...Ervin