Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 211612

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1112 AM CDT Sun May 21 2017


Issued at 330 AM CDT Sun May 21 2017

As of 3 AM: GOES IR satellite imagery depicted a dry slot over E
Iowa/NW Illinois, south of an upper-low over Minnesota. As a
result, skies were clearing across the DVN forecast area and temps
were falling through the 50s. West of the dry slot, wrap around
low stratus has already overspread central Iowa and is moving
east. Expect cloud cover to increase across the western CWA over
the next few hours.


.SHORT TERM...(Today and Tonight)
ISSUED AT 330 AM CDT Sun May 21 2017

Today and Tonight:

Stratus clouds on the back side of a slowly departing upper-level
low will increase from west to east through the early to mid
morning. As mentioned, the low will be slow to move out of the
Upper Mississippi Valley, so the low clouds will likely stick
around through much of the day leading to well below avg highs in
the mid 50s NW to lower 60s SE.

In addition to the cool temps, breezy west winds of 15-30 mph
will make it feel even cooler. Forecast soundings have a small
amount of SBCAPE during the afternoon and early evening that could
lead to some sprinkles. However, no measurable rain is expected.
Clearing skies tonight will allow temps to fall into the 40s.

.LONG TERM...(Monday through Saturday)
ISSUED AT 330 AM CDT Sun May 21 2017

Wet pattern continues Continued wet pattern through the extended
through the extended portion of the forecast.

Monday afternoon, wet weather returns as upper low over Ontario
continues to circulate and a short wave drops down the back side of
the low.  Surface convergence along the associated cold front, broad-
scale lift with the short wave, incoming mid level jet, and cold air
aloft suggest potential for some strong storms with this wave. SPC
has marginal risk for now, but this could be increased to slight
risk at some point per their discussion.

Midweek, cloudy, wet, and active weather continues as a closed low
drops into the Mississippi Valley.  With northwest low level flow
behind the cold front temperatures will be on the cool side of
normal.  Could see some wrap-around showers Tuesday and again
Wednesday before the surface ridge passes over and dry weather
returns for Thursday.

Looking toward next weekend, upper pattern finally shifts late in
the week with the upper ridge over the central US.  Starting Friday,
several short waves are progged to push into the ridge as a warm
front sets up near or over our area.  This suggests another round of
storms Friday and Saturday.  00z GFS has made a drastic change and
looks unrealistic with the strength and position of the surface low,
and have favored the ECMWF in this time frame.


.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
ISSUED AT 635 AM CDT Sun May 21 2017

MVFR ceilings will develop this morning as moisture and cool air
aloft advects in from the WNW. The height of the cloud bases will
slowly increase by the mid to late afternoon to VFR. West winds
of 15-25 kts are forecast from the mid morning through the
afternoon before subsiding this evening. Uttech


Issued at 1111 AM CDT Sun May 21 2017

Recent heavy rainfall from Friday and Saturday are resulting in
rises on many local rivers. In particular, the Iowa River at Marengo
continues to rise with a potential to reach flood stage by early
Tuesday morning. However, confidence still remains fairly low on
this potential, and therefore have elected to keep this location
under a watch.

Along the Mississippi, a flood watch has been issued this morning
for Dubuque as confidence has increased that routed flow and
tributary input will lead to minor flooding beginning later this
week. This has already occurred south over Burlington and
Gladstone, which are currently above minor flood stage this




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