Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 290445
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1145 PM CDT Sun May 28 2017

...AVIATION UPDATE...

.UPDATE...
Issued at 617 PM CDT Sun May 28 2017

A few weak showers and an isolated thunderstorm have developed
over the past hour in south central IA. These were ahead of a
weak upper level impulse and surface trough. As the associated
forcing appears to be moving out of an axis of higher CAPE and
thus better support, these should weaken, if not dissipate as
they advance eastward into southeast IA and far northeast MO early
this evening. Will update the forecast to mention isolated
evening showers along and south of the IA highway 34 corridor.

&&

.SYNOPSIS...
Issued at 356 PM CDT Sun May 28 2017

As forecast, the cold front exited the CWA early this morning, with
dry weather, lowering dewpoints, and highs in the mid to upper 70s
behind it. The 10 to 20 mph wind is actually quite pleasant in this
temperature range, and as readings cool off this evening, the wind
will also lower, thus, through sunset, it will continue to be an
outstanding day.

&&

.SHORT TERM...(This Evening through Monday)
ISSUED AT 356 PM CDT Sun May 28 2017

Clouds will decrease to clear skies around sunset tonight, with only
a few patches of mid clouds through the night possible in northwest
flow. AS the mixing depth decreases in this process, winds will also
drop to under 10 mph for the rest of tonight. The pressure gradient
will keep a light northwest wind going through the night, and lows
will be kept above the current dewpoints for that reason. Lows of
lower to mid 50s are solidly in the guidance blend range. Monday,
continued northwest flow will send another spoke of vorticity
southward, and this may allow for a similar uptick in cumulus by
late morning, followed by isolated to scattered showers. It seems we
will build these early enough in the day to keep the chances for
thunder quite low, and highs probably will only top out in the upper
60s north with the early cloud onset there. Farther south, with
milder air aloft, more sun is expected, and highs should once again
reach the mid 70s.
ERVIN

.LONG TERM...(Monday Night through Sunday)
ISSUED AT 356 PM CDT Sun May 28 2017

The trof over Quebec that has been a mainstay for a while will
continue to hold on.  Keeping us in an active weather pattern.
Guidance suggests that this will change the end of next week as a
deep trof moves on shore across the western US.

Long term sensible weather will be a continuation of Monday without
the chances for precip.  This is expected to continue through at
least Thursday morning, when the GFS and GEM suggest a wave through
the northwest flow.  This wave will help to advect in decent low
level moisture and our next chance for thunderstorms.  Guidance
suggests a summertime setup for nocturnal MCS with a LLJ and
instability Thursday morning through Friday morning.  The track of
any potential MCS will likely change before the day actually comes.
This is important to keep in mind.  If you have something to do
where you need dry conditions, get them done before Thursday.

Into the weekend, the flow becomes zonal to southwest.  This will
usher in warmer and more moist conditions and the chance for showers
and thunderstorms again.  Differences in model solutions lead to low
confidence at this time.  The GEM and ECMWF have NW flow across the
area, whereas the GFS is southwest with a compact wave moving into
the area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
ISSUED AT 1145 PM CDT Sun May 28 2017

Conditions will remain VFR overnight through Monday. Isolated
showers or sprinkles will be possible with weak surface fronts
rotating through tonight and again Monday afternoon. These are
expected to be too isolated and low impact to include in the
forecasts at this time. Surface winds will again increase and
become gusty from mid morning through afternoon, then diminish to
less than 10 knots after sunset.

&&

.HYDROLOGY...
Issued at 919 PM CDT Sun May 28 2017

The Mississippi at Burlington has been upgraded to major category
flooding as forecast confidence has increased that levels will
reach or exceed 18 feet Wednesday night or early Thursday morning.

Otherwise, flood warnings continue for most other sites along the
Mississippi River for minor to moderate flooding. Flood watches
remain in effect at Bellevue (BLVI4), and Keokuk (EOKI4), where
forecasts indicate levels reaching or just exceeding flood stage
this week, but forecast confidence is low.

&&

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

$$

UPDATE...Sheets
SYNOPSIS...Ervin
SHORT TERM...Ervin
LONG TERM...Gibbs
AVIATION...Sheets
HYDROLOGY...Sheets



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