Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 011152
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
652 AM CDT SAT OCT 1 2016

...12z AVIATION UPDATE...

.SYNOPSIS...
Issued at 322 AM CDT Sat Oct 1 2016

The latest sfc analysis was indicating the main low acrs the
southern IL/IN border region, with SFC pressure falls increasing
acrs northern IND showing the way this wave will migrate toward this
morning. The closed upper low center leaned a bit further to the
east acrs the north central KY portion of the OH RVR Valley.
Associated main spiral band of showers/light rain was moving down
acrs the northeastern half of the DVN CWA out of WI/northern LK MI.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 322 AM CDT Sat Oct 1 2016

Today...Mid and upper level jet flow wrapping around eastern flank
of the upper low will allow it to gyrate to the north and northeast
toward northeastern IND and southern Lower MI by this evening. In
the mean time, the cyclone complex will continue to spiral a cloud
shield and embedded areas of light showers/rain toward the local
area today, with occasional mid layer dry air entrainment making for
more drizzle or sprinkles at times. Similar air mass supports
widespread highs in the low to mid 60s, with a few areas pushing the
upper 60s again in areas that manage to get a few breaks/thinning in
the overcast. Thus a similar day as yesterday(Friday). A few areas
east of the MS RVR may get a few hundredths to just under a tenth of
an inch of rainfall accumulation, while most areas experience just a
trace.

Tonight...The blocked upper low continues to get acted upon and
migrates to the northeast acrs the central into the eastern GRT LKS
basin by Sunday morning. It appears there will be less support for
even light precip generation and propagation into the local area and
expect a waning in even sprinkle activity as the evening progresses.
Upstream sfc ridge adjusts acrs eastern MN into central IA, and if
enough breaks can occur in the overcast close to the lighter wind
regime of the ridge, there may be some fog possibilities in central
IA and creeping into the western DVN CWA toward Sunday morning. But
currently with lower confidence in this potentail, will just go with
patchy fog in the far west late tonight. Most lows in the mid to
upper 50s under lingering cloud cover.   ..12..

.LONG TERM...(Sunday through next Friday)
ISSUED AT 322 AM CDT Sat Oct 1 2016

Cyclonic flow with the departing upper low may keep low clouds over
at least the eastern half of the forecast area through Sunday
morning and possibly into the afternoon. While not mentioned in the
current forecast, a few models are suggesting sufficient low level
moisture for drizzle or light rain in the morning before a more
subsident regime builds into the area. Anticipating thinning
afternoon clouds, have optimistically held highs in the upper 60s to
lower 70s.

Surface and upper level ridging then provides dry weather and above
normal temperatures Sunday night through Tuesday. Increasing
moisture ahead of a deep low moving into the western U.S. brings
chances for showers Tuesday night, with better chances for showers
and thunderstorms Wed into Wed night, where the better moisture feed
is shown pushing PW values as high as 1.5 inches along with with
steeper mid level lapse rates. Pops have been increased to likely
category for much of the area Wed into Wed night when the passing
low to the north sends a frontal boundary through the region. Highs
should push well into the 70s Tue and Wed, but then cool back into
the 60s late in the week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
ISSUED AT 640 AM CDT Sat Oct 1 2016

A large cyclone moving north toward lower MI will continue to
whirl MVFR to IFR CIGS acrs the area today, with most sites
becoming MVFR by late morning. Passing bouts of light rain and
drizzle will temporarily lower VSBYs to 3-5SM with some associated
light fog. The precip will become more spotty this afternoon and
into the evening before really waning tonight. Will follow the
guidance and lower CIGS back to IFR levels after 9-11 PM tonight,
but confidence is lower that they will decrease to that extent. If
any breaks in the cloud cover occur, with light north/northwest
winds there may be some more fog development of at least MVFR
category in the overnight into early Sunday morning.   ..12..

&&

.HYDROLOGY...
Issued at 322 AM CDT Sat Oct 1 2016

Flood crest is now near Dewitt, where the Wapsipinicon appears to be
steady near 13.8 feet, and near Oakland on the Iowa, around 16.3
feet. Stages continue to fall further upstream along the eastern
Iowa tributary rivers, with the exception of the Iowa at Marengo,
where routed flow from upstream has recently pushed it into moderate
flooding.

Along the Mississippi...only minor adjustments made to forecasts
with flooding continuing at most forecast points.

&&

.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...Sheets
AVIATION...12
HYDROLOGY...Sheets



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