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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
350 am CDT Tuesday may 5 2015

Synopsis...
issued at 330 am CDT Tuesday may 5 2015

At 3 am CDT...widespread showers and isolated thunderstorms
continued over much of eastern Iowa and northwest Illinois...with
the moderate to heavy rain confined mainly along and east of the
Mississippi River. The heaviest rainfall amounts so far have
fallen in 2 main corridors...along Highway 30 and south of Highway
34. Rainfall totals so far of 1 to 2 inches have been common in
these areas...with localized amounts of 3 to 4 inches based on
Doppler radar estimates.

&&

Short term...(today and tonight)
issued at 330 am CDT Tuesday may 5 2015

Latest radar trends support high resolution models that gradually
lift the focus of the showers and embedded thunderstorms into the
northern forecast area through the early morning hours. The east-
west oriented frontal boundary is expected to remain entrenched
roughly around the Interstate 80 corridor through the day...with
additional more scattered rain primarily focused along and north
of the boundary in an airmass with precipitable water values over 1 inch.
Additional rainfall amounts will be highest from Dubuque to
Freeport and Princeton...potentially an inch or so. The threat for
severe thunderstorms is low. Any additional flooding issues will
likely be limited to nuisance ponding water in urban areas...and
water encroaching onto roads from rain filled ditches. The threat
for legitimate flash flooding with a threat to life or property is
low. Many area rivers are showing some modest in bank rises...but
there are no concerns in the near term. Afternoon temperatures are
expected to be held down in the 60s far north today...with 70s
central to near 80 degrees south. For tonight...some lingering
showers/isolated thunderstorms will be possible in the far
northeast.

Long term...(wednesday through monday)
issued at 330 am CDT Tuesday may 5 2015

Confidence is high that an active weather pattern will remain in
place through the weekend and into early next week. Confidence is
low on the timing of rainfall and amounts. The wet pattern will
result in rises on area rivers over the next 7 to 10 days.

Nearly all of the area should be dry Wednesday morning as the better
forcing is well west of the area. The question is will precipitation
develop Wednesday afternoon.

Internally...several of the models point to some convection
developing. The trigger appears to be the approaching upper level
disturbance which would support some diurnal convection developing
over the western half of the area in the afternoon and dissipating
with sunset.

Late Wednesday night and into Thursday the models are signaling a
potential thunderstorm complex developing and moving across the
area. The overall forcing/moisture is there with the only question
being when and where the complex develops and tracks.

Thursday night...more convection is expected with another front
approaching the area. Once again...the models internally are
suggesting the potential development of another thunderstorm
complex.

Friday on...

The active weather pattern will continue from Friday through next
Tuesday. There will be periods of dry weather from Friday through
Tuesday that may be 6 or more hours in length. Timing when these dry
periods occur is difficult because where one thunderstorm complex
develops and tracks will influence where the next storm complex
develops and tracks.

As such the model consensus has chance to likely probability of precipitation in each period
from Friday through Monday. The model consensus has slight chance
probability of precipitation Monday night and Tuesday. Temperatures should generally
around or slightly above normal through the period.

&&

Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 633 PM CDT Monday may 4 2015

Widespread showers and thunderstorms will overspread the region
tonight with extended periods of MVFR and probably higher end IFR
conditions in rain. Conditions should improve by middle to late
morning as a warm front moves north. Winds will be from the east
at 5 to 10 kts...becoming south to southeast at 5 to 15 kts by middle
day on Tuesday.

&&

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

$$

Synopsis...rp Kinney
short term...rp Kinney
long term...08
aviation...Nichols

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