Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 222050
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
250 PM CST Fri Feb 22 2019


.SYNOPSIS...
Issued at 248 PM CST Fri Feb 22 2019

18Z surface data has high pressure from the Great Lakes into the
upper Midwest with a developing storm system in the southern
Rockies. Dew points were in the teens and 20s from the Great Lakes
into the central Plains. Dew points in the 30s and higher ran from
the Ohio Valley into the southern Plains down to the Gulf Coast.

&&

.SHORT TERM...(This Evening through Saturday)
ISSUED AT 248 PM CST Fri Feb 22 2019

Bottom Line Up Front

Have expanded the winter weather advisory for tonight and Saturday
morning down to the I-80 corridor. The atmosphere is drier that what
the models depicted which will delay the onset of precipitation but
should allow more areas to see ice accumulation.

Tonight

Precipitation will be slow to start with it not beginning until
between 9 PM and midnight. As forcing increases late tonight the
precipitation will quickly expand in areal coverage. The area most
at risk for the higher ice accumulations is along and north of
Highway 30. Some areas may approach one quarter inch of ice
accumulation.

Generally south of an Ottumwa, IA to Galesburg, IL line the
precipitation will remain as all rain.

Saturday

The wintry mix of precipitation will change over to all rain north
of I-80 by late morning. The overall intensity of the rain may
decrease from late morning through early afternoon.

By mid to late afternoon the forcing will increase significantly as
the main surface low approaches and a very strong upper level
disturbance moves through the area. This strong forcing combined
with the atmosphere becoming unstable should allow rainfall
intensity to increase across the area and allow embedded
thunderstorms to develop.

If the thunderstorms that develop can pull down the higher winds
aloft, localized wind gusts of 45 mph are possible. Small hail
is possible from the stronger storms.

.LONG TERM...(Saturday Night through Friday)
ISSUED AT 248 PM CST Fri Feb 22 2019

Forecast focus on intense storm system this weekend.

Headline: High wind watch issued for Saturday night into Sunday
evening for potential wind gusts to around 55 mph.

Saturday night: Deepening low pressure will be moving near the Quad
Cities in the evening, with the cyclone tracking to eastern Upper MI
by sunrise Sunday (979 mb). Rain and isolated thunderstorms during
the evening will turn to a mix of freezing rain and sleet then
changing to all snow from west to east overnight. There is the
potential for around an inch in our far nw counties with lesser
amounts elsewhere. Gradient really tightens up as the low continues
to deepen with strong winds and falling temps. Northwest winds
gusting to 50 mph can be expected, and where the snow is occurring
could result in considerable blowing and drifting. Lows will range
from the upper teens nw to the 20s elsewhere.

Sunday: The cyclone will continue to deepen to 970 mb as it moves to
Ontario. High winds are expected with gusts to around 55 mph but
much of the day will be dry. Highs should be early in the morning in
the 20s to lower 30s then gradually falling temperatures. Wind
chills all day will be in the single digits and teens.  The winds
will be diminishing Sunday evening.

Sunday night through next Friday: Well below normal temperatures
with chances for light snow, but low confidence in the
timing/location of any upper air disturbances in the nw flow.
The GFS does suggest March coming in like a lion on Friday with the
potential for another intense storm system impacting the Midwest.
However, the ECMWF is much weaker with the system. Obviously, low
confidence this far out.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
ISSUED AT 1141 AM CST Fri Feb 22 2019

VFR conditions will continue through 03z/23 as high pressure moves
into the eastern Great Lakes. After 03z/23 conditions will
deteriorate to MVFR and then IFR as the next storm system moves
into the area. KCID/KDBQ are most at risk for seeing freezing
rain. No LLWS was included in the 18z TAFs as it appears to be
marginal.


&&

.HYDROLOGY...
Issued at 1156 AM CST Fri Feb 22 2019

Moderate to possibly heavy rainfall Saturday into Saturday
evening, combined with temperatures above freezing and snowmelt,
will result in new rises on area rivers. With confidence still
somewhat low in regards to rainfall amounts, have opted to issue
flood watches for the following locations: Wapsipinicon River at
De Witt, English River at Kalona, Skunk River at Augusta, Rock
River near Joslin, and the Rock River at Moline. These rivers are
forecast to rise to minor flooding by early next week. However,
the timing and ultimate crest height will depend on the amount of
rainfall so forecasts could change. Complicating the situation
will be the amount of snowmelt and runoff into the rivers.

With river levels already running higher than normal, flooding is
again possible either through runoff or break up ice jams, and may
impact other rivers in the area as well.


&&

.CLIMATE...
ISSUED AT 248 PM CST Fri Feb 22 2019

Week 2...March 2st to March 8th

A significant arctic outbreak will affect the Midwest in early
March.

The Climate Prediction Center has a high risk for much below normal
temperatures, especially low temperatures.


&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory from midnight tonight to 10 AM CST
     Saturday for Benton-Buchanan-Cedar-Clinton-Delaware-Dubuque-
     Iowa-Jackson-Johnson-Jones-Linn-Muscatine-Scott.

     High Wind Watch from late Saturday night through Sunday evening
     for Benton-Buchanan-Cedar-Clinton-Delaware-Des Moines-
     Dubuque-Henry IA-Iowa-Jackson-Jefferson-Johnson-Jones-
     Keokuk-Lee-Linn-Louisa-Muscatine-Scott-Van Buren-Washington.

IL...Winter Weather Advisory from midnight tonight to 10 AM CST
     Saturday for Bureau-Carroll-Henry IL-Jo Daviess-Putnam-Rock
     Island-Stephenson-Whiteside.

     High Wind Watch from late Saturday night through Sunday evening
     for Bureau-Carroll-Hancock-Henderson-Henry IL-Jo Daviess-
     McDonough-Mercer-Putnam-Rock Island-Stephenson-Warren-
     Whiteside.

MO...High Wind Watch from late Saturday night through Sunday evening
     for Clark-Scotland.

&&

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...Haase
AVIATION...08
HYDROLOGY...Haase
CLIMATE...08


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