Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 260343
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
943 PM CST Sat Feb 25 2017

.UPDATE...
Issued at 936 PM CST Sat Feb 25 2017

Have updated for min temps as a few sites have dropped at or
below forecast with light winds and clear to partly cloudy
skies. Expect temps to become steady if not rise a few degrees
overnight in response to increasing southerly wind and mid
cloudiness within WAA on backside of departing high pressure
ridge.

&&

.SYNOPSIS...
Issued at 243 PM CST Sat Feb 25 2017

Scattered flurries tapered off during the early afternoon hours,
as did a narrow band of river enhanced light snow showers
that set up just south and east of Moline. Early afternoon
temperatures ranged from the low 20s along Highway 20, to the low
30s near Keokuk. The sky was partly to mostly sunny during the
early afternoon, with lingering low clouds east of the Mississippi
River, and increasing high clouds in southeast Iowa.

&&

.SHORT TERM...(This Evening through Sunday)
ISSUED AT 243 PM CST Sat Feb 25 2017

High and eventually mid-level clouds will be on the increase from
the west tonight as a surface high pressure ridge pushes quickly
across the forecast area. With a slackening breeze and recent
snow cover, albeit light, lows will occur this evening followed by
increasing clouds, a stronger south wind, and steady to slowly
rising temperatures after midnight. Have favored cooler temps
across the lingering snow cover to the north.

For Sunday expect an increasing southwest breeze, sustained at 15
to 25 mph from late morning on. WAA will quickly melt off the
lingering snow cover. Expect afternoon highs in the 40s, which is
5 to 10 degrees above normal for late February.

.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 243 PM CST Sat Feb 25 2017

An active weather pattern will be seen over the next 7 days. A
warming trend is on tap the first part of next week with a brief
cool down the second half of the week. Temperatures will however
average above normal.

A secondary concern is area river levels from the snow melt the
previous week, the heavy rain last Thursday night, and expected
rainfall/snow melt next week. Refer to the hydro section for
information on area rivers.

Quiet and dry conditions will be seen across the area Sunday night
and Monday as high pressure moves through the Midwest. Temperatures
are expected to average above normal. Attention then turns to the
first of two storm systems.

Monday night into Tuesday the first of two storm systems will move
through the Midwest. Warmer air being pulled north into the area
looks to keep the precipitation as all rain. Temperatures will
average well above normal.

Tuesday night on...

The second storm system will move through the area Tuesday night
into Wednesday right behind the previous storm system. Colder air
behind pulled in with the second storm will allow a rain/snow mix to
develop over the northwest half of the area late Tuesday night and
Wednesday morning that may change over to all snow northwest of a
Sigourney, IA to Monroe, WI line.

A lingering rain/snow mix or light snow will be seen east of the
Mississippi Wednesday evening followed by dry conditions after
midnight.

Thursday will start out dry by a weak upper level disturbance
will move through the area Thursday afternoon and evening.
Thermal profiles of the atmosphere will be critical in determining
precipitation type. However, it does appear that a rain/snow mix
is possible Thursday afternoon that may briefly change over to all
snow before ending Thursday evening.

A period of dry weather is expected late Thursday night through
Saturday. The exception looks to be late Friday night as a weak
upper level disturbance moves through the western Great Lakes that
may produce some light snow across northwest Illinois.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 519 PM CST Sat Feb 25 2017

Vfr conditions expected with diminishing winds tonight shifting
from northwest to southwest in the wake of a passing high
pressure ridge. On Sunday southwest winds will increase by mid
morning at 10-20 kts and gusty.


&&

.HYDROLOGY...
Issued at 243 PM CST Sat Feb 25 2017

Heavy rainfall from northeast Iowa into southern Wisconsin last
Thursday night combined with snow melt the previous week will result
in rises on area rivers. Warmer temperatures next week will start
melting snow across northern Iowa into Wisconsin and two rain events
are forecast. This additional water will also make its way into area
rivers. Individuals with interests along area rivers are urged to
pay attention to weather and river forecasts over the next 7 to 10
days.

Iowa tributary rivers...

Iowa tributary rivers will see rises over the next 7 to 10 days,
especially the Wapsipinicon, Cedar, and Iowa rivers. Several
locations are forecast to approach flood stage. The Cedar river near
Conesville is expected to crest around 0.5 feet above flood stage
early next week. How much rain occurs next week and how quickly the
snow melts across northern Iowa will be critical factors on how high
river levels will get.

Mississippi River...

The Mississippi river will rise considerably over the next 10 days
with the river forecast to approach or go into flood in early March.
Much of the flow is already accounted for with the Wisconsin river
providing a considerable flow input into the Mississippi.

What is not fully accounted for is the rainfall expected next week
and how much of the snow pack across the upper Midwest will melt due
to warmer temperatures. Additionally, freezing temperatures will
initially lock up some of the water until the warmer air arrives.

The overall forecast trend for Mississippi river levels has been
downward over the past several days. How much rainfall occurs next
week and how much of the snow up north melts will be key factors in
determining river levels on the Mississippi over the next 10  to 14
days.

Northwest Illinois tributary rivers...

The Pecatonica, Rock, and Green rivers are currently forecast to
remain below flood stage. Heavy rainfall that occurred in northwest
Illinois and southern Wisconsin combined with snow melt is expected
to create within bank rises on the Pecatonica and Rock rivers.

The heaviest snow across Wisconsin will melt and go into the
Wisconsin river basin when warmer temperatures arrive next week. How
much rain occurs next week will be important in determining river
levels in northwest Illinois over the next 7 to 10 days.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

UPDATE...McClure
SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...08
AVIATION...McClure
HYDROLOGY...08



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