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fxus63 kdvn 230824 
afddvn

Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
324 am CDT Mon Sep 23 2019

Synopsis...
issued at 322 am CDT Mon Sep 23 2019

Cold front off to the east continues progressing into the Ohio
Valley. In it's wake high pressure is building in providing
tranquil conditions early this morning. Light winds and wet
ground from recent rainfall is resulting in some dense fog
over central Iowa. The fog is still rather patchy, but continues
developing toward eastern Iowa with the core of the surface ridge.

&&

Short term...(today and tonight)
issued at 322 am CDT Mon Sep 23 2019

A very nice first day of fall is on tap, as high pressure traverses
the region providing dry and less humid conditions. Patchy to
areas of fog (west) and low clouds (east) will quickly give way to
plentiful sunshine. The abundant solar insolation will allow
temperatures to moderate into the lower to mid 70s for afternoon
highs, which is right about normal for the date.

Tonight, mainly clear to partly cloudy. Lows will once again slip
back into the 50s coolest east in closer proximity to departing
surface ridge. Temperatures may hold steady or possibly even rise
a bit overnight with developing southerly flow /warm advection.
Overall increase in wind overnight should abate fog threat for
most, although can't rule out some patchy fog into portions of Illinois
closer to the departing high.

Long term...(tuesday through sunday)
issued at 322 am CDT Mon Sep 23 2019

Tuesday: high pressure will slip off to our east with a nice return
flow of increasing moisture on southerly winds. Highs should push
well into the 70s to around 80 but depending on amount of sunshine,
these readings may be several degrees too cool. Towards evening the
dewpoints will be rising into the 60s.

Tuesday evening/night: Storm Prediction Center has a slight risk for severe storms in
portions of eastern Iowa with a marginal risk over the remainder of
the cwa. A strong h3 jet Max of 100 kts will be pushing across the
upper Midwest as a broad cyclonic flow develops. At h5 winds
increase to 50-60 kts across Iowa with a swly low level jet of 30-40 kts. This
will create strong shear and as a cold front pushes southeast into
southern Minnesota and western Iowa supercells should develop west of the dvn
cwa towards Tuesday evening. Models suggest some this activity
getting into our NW cwa during the evening where the slight risk
exists. What remains to be seen is can this activity congeal into a
squall line with damaging winds (instead of discrete supercells),
and how much weakening occurs overnight.

The front will push across the cwa on Wednesday with chances for
thunderstorms. Cooler behind the front with highs mainly in the
lower to mid 70s.

Wednesday night and thursday: high pressure brings fall-like
temperatures and low humidity, along with clear to partly cloudy
skies. Lows should bottom out in the upper 40s to lower 50s,
with highs in the upper 60s north to lower to mid 70s south.

Thursday night through the weekend: active pattern sets up with
periodic rounds of showers and thunderstorms. Heavy rainfall and
severe weather are all on The Table. Upper level trough and
deepening cyclone will move across the upper Midwest late this week.
Then this weekend GFS/European model (ecmwf) suggests the pattern becoming highly
amplified with a major trough in the west and big ridge in the east.
This sets up a frontal boundary laying SW-NE across the Midwest with
numerous showers and storms along and near this boundary. The
western Gulf will be open for business with plentiful low level
moisture being transported into the area. Any additional rain may
aggravate river flooding. Stay tuned!

&&

Aviation...(for the 06z tafs through 06z Monday night)
issued at 1142 PM CDT sun Sep 22 2019

Patchy MVFR vsbys are possible around sunrise due to light winds
and clear skies. Otherwise expect VFR conditions through 06z/24 as
high pressure moves through the Midwest.

&&

Hydrology...
issued at 916 PM CDT sun Sep 22 2019

A widespread 1 to 3 inch rainfall event is now included in the
river forecasts from rain hat fell over the weekend. The timing
of runoff into area rivers may change as more reports are received
which could further change river forecasts potentially slightly
lower.

Have lowered the forecasts slightly on the Rock River for Moline
and near Joslin. Joslin is now forecast to crest at 14.0 feet
which is still moderate flood stage. The forecast for Moline was
lowered to a crest o 12.8 feet which is minor flooding.

The forecast for the Pecatonica River at Freeport has been lowered
slightly to 14.0 feet which is the moderate flood stage.

River flood forecasts have also been lowered slightly on the
Mississippi River from Rock Island lock and dam 15 southward to
Burlington. The Flood Watch for the Mississippi River at
Camanche has been canceled as the river is forecast to stay below
flood stage.

A wet pattern is forecast to continue through the next week.
This potential rainfall is not included in the Current River
forecasts.

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

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