Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 230009

Area Forecast Discussion
National Weather Service Quad Cities IA IL
609 PM CST Sun Jan 22 2017


Issued at 330 PM CST Sun Jan 22 2017

There were only a few fleeting breaks in the cloud cover across
the area through the early afternoon hours. Dense fog that
lingered during the morning hours lifted during the early
afternoon. A narrow band of light rain and sprinkles extended from
far southeast Iowa through west central Illinois through early
afternoon. Temperatures ranged from the mid 30s to low 40s.


.SHORT TERM...(This Evening through Monday)
ISSUED AT 330 PM CST Sun Jan 22 2017

Main challenge for the short term period is evaluating potential
for more dense fog tonight into Monday morning.

Various visibility progs indicate potential for some pockets of
dense fog advecting southward across parts of the forecast area
overnight. Still plenty of uncertainty regarding coverage, timing,
and how low visibilities will drop. The lightest northerly winds
will generally be across the northwest third to half of the
forecast area. If widespread dense fog develops, it may be
concentrated mostly in this area. Will continue to highlight in
the forecast grids and Hazardous Weather Outlook, but there is too
much uncertainty to issue an advisory at this time. Lows tonight
will likely be warmer than last night with the extensive cloud
cover, so freezing fog should not be much of an issue in terms of
slick roads.

For Monday, after the lingering fog diminishes in the late
morning, expect a mostly cloudy sky and another day of
unseasonably mild temperatures. Highs will vary from the upper 30s
to low 40s.

.LONG TERM...(Monday Night through Sunday)
ISSUED AT 330 PM CST Sun Jan 22 2017

Forecast focus on the potential for accumulating snow in our north
Tuesday night into Wednesday.

Tuesday through Wednesday: Intense cold upper low currently spinning
off the Pacific northwest coast will dive southward and then kick
out a strong cyclone in the Midwest towards mid week. (There are
quite a few lightning strikes showing how intense it is). The ECMWF
has been consistent in taking the 990mb low across eastern IA
Tuesday night, and then into lower MI on Wednesday. However, the GFS
has taken more of a northwest track into extreme northeast IA, north
of the dvn cwa. This current forecast is based on the more
consistent southerly path of the ECMWF with the potential for
several inches of snow accumulation in our northern counties. As of
now, the heaviest snow should occur along Highway 20 where 2 to 4
inches are possible, with even heavier amounts of 6+ inches west and
north of the dvn cwa. Way too early for any possible headlines in
our cwa and the exact track of the cyclone is not etched in stone
just yet, and if there is a more northerly path per GFS snow amounts
will be greatly reduced.

Ahead of the system some rain should develop Tuesday afternoon with
highs in the 40s with the rain changing to snow Tuesday night, as
the stronger forcing/colder air arrive.

Thursday through Sunday: A major pattern change to a northwest to
northerly flow aloft, as a deep trough sets up in the eastern United
States, with ridging in the Rockies. This looks to be a mostly
cloudy period with temperatures on the cold side but nothing
extreme. In fact, readings should be closer to normal for late

There is the possibility of periodic episodes of snow showers or
flurries as weak disturbances move through the flow. However,
moisture looks minimal so no significant accumulations expected.
Low confidence this far out in timing of these individual waves.


.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
ISSUED AT 554 PM CST Sun Jan 22 2017

Ceilings and visibilities to remain variable across the TAF sites
this evening. Initially VFR conditions will be found at MLI, while
IFR/MVFR conditions generally found at CID/DBQ/BRL. Overnight
with cooling and moisture plus advection expect cigs to lower
mainly into IFR but kept visibilities at or above 1-2sm with NW
winds 5-10 kts. Can`t rule out some lower visibilties in dense
fog should winds lay down more than anticipated. On Monday, expect
visibilities to improve to VFR, while cigs lift MVFR.


Issued at 330 PM CST Sun Jan 22 2017

The rivers are now showing a falling trend with only a few still in
flood. The only forecast site in moderate flood is Moline, and later
tonight the Rock at Moline should fall into minor category.
Apparently much of the ice in the rivers has either melted or at
least broken up enough that the rivers have not shown the wild
fluctuations exhibited yesterday.

The river to monitor will be the Iowa at Marengo as the forecast
brings it back above flood stage Monday night, and if this trend
continues then a flood watch may be needed.




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