Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 270744

Area Forecast Discussion
National Weather Service Quad Cities IA IL
244 AM CDT Thu Jul 27 2017

Issued at 240 AM CDT Thu Jul 27 2017

SPC Mesoanalysis had a sfc trough over southern Illinois and
central Missouri, extending to the SW into the Panhandle of Texas.
It was along this axis where the organized convection was
located. North of the trough/low-level boundary, there were
residual areas of light showers and sprinkles, but mostly south of
I-80. The atmosphere was still very humid across all of E Iowa/NW
Illinois with dewpoints in the 70s.

Patchy fog is possible early this morning - mostly in low-lying
areas. It could be briefly dense; however, this should be of the
localized, shallow ground fog variety. Thus, do not anticipate
much in the way of impacts to travel.


.SHORT TERM...(Today and Tonight)
ISSUED AT 240 AM CDT Thu Jul 27 2017

Warm and continued humid today. Highs are forecast in the lower to
middle 80s. Dewpoints in the upper 60s to lower 70s will hang on
for locations south of highway 30 into the mid to late afternoon.
But across the northern tier or two of counties, modest dry air
advection should drop dewpoints into the mid 60s.

There is a slight chance for air mass showers (possibly an
isolated weak storm) to develop during peak heating south of
highway 30, especially along a southward moving boundary, as
indicated by the HRRR/3km NAM. Coverage will remain low and most
locations will not receive measurable rain today. The refreshing,
much drier air overspreads E Iowa/NW Illinois tonight. Lows are
forecast in the lower 60s on avg. Uttech

.LONG TERM...(Friday through Wednesday)
ISSUED AT 240 AM CDT Thu Jul 27 2017

Quiet, dry, and nice conditions will be seen across the area Friday
through Saturday night as Canadian high pressure slowly moves
through the Midwest. Temperatures should average slightly below

Sunday on...

The quiet and dry conditions will continue Sunday through Tuesday
night as Canadian high pressure slowly moves into the Ohio Valley.
Temperatures should be around or slighly below normal.

Starting Wednesday the models diverge on their respective solutions.
the CMC and GFS bring another cold front through the area Wednesday
afternoon/night. The ECMWF delays the front by 24 hours and has it
associated with a seasonably strong upper level disturbance. As a
result, the model consensus has slight chance to chance pops for
Wednesday afternoon/night. Temperatures should be close to normal.


.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
ISSUED AT 1157 PM CDT Wed Jul 26 2017

A weak front moving through the area tonight will provide a few
showers and then sufficient low level moisture convergence to lead
to low clouds and fog formation. With the latest forecasts, have
lowered conditions to IFR for a period at BRL, DBQ and MLI, with
CID at least going into low MVFR. There is also a low potential
for a thunderstorm at BRL, which is not mentioned in the forecast.
Overall, confidence in just how low visibilities and ceilings
will go is below average at all sites. Thursday, incoming drier
air will lead to VFR conditions by mid morning. There will
continue to be a low potential for an isolated shower or
thunderstorm, especially at BRL, which is not mentioned at this


Issued at 240 AM CDT Thu Jul 27 2017

There is a slight chance of thunderstorms today with the better
chances south of I-80. An extended period of dry weather will be
seen across the entire area Thursday night through next Tuesday
night. This dry weather will allow area waterways to go below flood
stage and allow the saturated ground across northeast Iowa and
northwest Illinois to dry out. Elevated readings on all area
waterways are expected into early August.

The localized heavy rain last evening created brief minor jumps in
river levels due to runoff.

Wapsipinicon River...

Independence is below flood stage. The flood crest is just past
Central City. Downstream of Central City, moderate flooding is
forecast at Anamosa Shaw Road with major flooding near DeWitt.

Rock River...

The flood crest has entered the Mississippi but major flooding
continues along the Rock river. Como and Joslin experienced a brief
jump in river levels from the storms last evening but both are now
falling. Moline continues to slowly fall.

Pecatonica River...

Major flooding continues in Freeport. Freeport will rise to around
15.7 feet by Saturday as more flow from upstream moves through the
basin before falling again on Sunday. The roughly half foot increase
in river levels will increase flood impacts around the Freeport area.

Yellow Creek...

Creek levels are now within banks. Some road closures may still be
ongoing. Any further lowering of water levels along Yellow Creek
will be delayed as the Pecatonica river starts rising again.

Mississippi River...

Flood warnings remain in effect for minor flooding from Illinois
City down to Burlington. The flood crest is at New Boston and
approaching Keithsburg. Gladstone and Burlington will crest today
and tonight respectively.




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