Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 201759
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1159 AM CST Fri Jan 20 2017

.UPDATE...
Issued at 1148 AM CST Fri Jan 20 2017

Will allow the Dense Fog Advisory expire at noon, although a few
pockets dense fog acrs portions of southeastern IA and
northeastern MO through at least 1 PM CST. Will assess the need
for another fog advisory tonight by issuance of the afternoon
fcst package.

&&

.SYNOPSIS...
Issued at 330 AM CST Fri Jan 20 2017

Recent widespread rainfall over the past several days and a
moist easterly flow tonight are allowing sfc dewpoints to hold in
the mid to upper 30s. High sfc RH has, as expected, led to
widespread fog and areas of drizzle. Locations roughly west of a
Dubuque, IA to Clinton, IA to Galesburg, IL line have experienced
periods of dense fog. The most persistent dense fog, with
visibilities of 1/4 mile or less, have been approximately along
and south of a Sigourney, IA to Quad Cities to Galesburg, IL line.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 330 AM CST Fri Jan 20 2017

This Morning:

Dense Fog Advisories in effect across the forecast area through
12 PM (with the exception of the far eastern tier of counties in
IL including Jo Daviess).

Fog to gradually wane through the mid to late hours as shown by
RAP/HRRR/NMM. Conceptually, light winds and negligible advection
of dry air support slow improvement in visibilities this morning.

This Afternoon and Tonight:

Sfc-500mb flow remains southerly, maintaining the moist and mild
conditions. 500mb vort. max and subtle sfc-850mb west-to-east
oriented trough axis progged to work northward through the region
late this afternoon into tonight. 925-800mb column theta-e
advection and weak frontogenesis will likely develop areas of
drizzle and possibly spotty areas of light rain. This evening and
tonight...widespread fog is forecast once again, some of which
could become dense. Left out mention of severity in the grids at
this point. Later shifts will have to assess latest obs and model
trends. Uttech

.LONG TERM...(Saturday through Thursday)
ISSUED AT 330 AM CST Fri Jan 20 2017

Above average temperatures continues to be the main story
throughout.

Saturday: have added fog to the morning and with the amount of
lingering moisture, to what extent things clear out during the day is
questionable. For now, will stay with an optimistic clearing trend,
allowing temperatures to reach the mid 40s to mid 50s. If clouds
were to persist, temperatures would not exceed the 40s.

The next wave of low pressure is progged to pass through the area
Tue night into Wed, and chances for rain, and then a low confidence
transition to a rain/snow mix is mentioned for late night into early
morning.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
ISSUED AT 1148 AM CST Fri Jan 20 2017

Although VSBYS will continue to temporarily improve to MVFR
levels this afternoon, CIGs may have trouble rising above LIFR in
some spots especially south, with others staying at IFR.
Southeast sfc winds of 4-7 KTs through this evening. Tonight,
expect VSBYs to lower again to LIFR from dense fog reformation a
few hours after sunset. Drizzle will increase as well, or even a
few bouts of spotty light rain. But as a front pushes north
through the area and switches the winds to the south, expect
improvement in VSBYs again from south-to-north after midnight into
early Sat morning. But DBQ and possibly CID may stay socked in
with LIFR until after 12z Sat.  ..12..

&&

.HYDROLOGY...
Issued at 234 AM CST Fri Jan 20 2017

Rock River: Flood warnings for moderate flooding continue at Joslin
and Moline. At Joslin, the river appears to have crested Thursday
evening and has since begun to recede. At Moline, we have increased
the warning to major flooding. Early this morning, law enforcement
reported water had risen over North Shore Drive, which is a known
impact of major flooding. Ice action appears to be hindering
reliable gage readings at this site.

Mississippi River: The latest river stage trends indicate that the
river has crested at Gladstone and moderate flooding continues.
At Burlington, major flooding continues due to the elevated flow
levels and impact of the downstream ice jam. Recent readings show
levels appear to be leveling off, after having risen over the past 5
days. The watch for the eventual erosion of the ice jam continues,
and once the ice jam gives way, expect the levels in the river
around the affected sites in flood to drop noticeably.

Other sites: Recent and forecast rainfall/run-off, combined with ice
action is also producing rises to or near the flood stage at some
sites on the Iowa River in Iowa. With the ongoing mild weather and
more rainfall forecast, area rivers in general will still have to be
watched into the start of the weekend for more ice action and jams
possibly producing additional flooding.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Dense Fog Advisory until noon CST today for Benton-Buchanan-Des
     Moines-Henry IA-Iowa-Jefferson-Johnson-Keokuk-Lee-Linn-
     Louisa-Van Buren-Washington.

IL...Dense Fog Advisory until noon CST today for Hancock-Henderson.

MO...Dense Fog Advisory until noon CST today for Clark-Scotland.

&&

$$

UPDATE...12
SYNOPSIS...Uttech
SHORT TERM...Uttech
LONG TERM...Sheets
AVIATION...12
HYDROLOGY...Sheets



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