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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
657 am CDT sun Mar 29 2015

Update...
issued at 647 am CDT sun Mar 29 2015

Rain continues to move into the area. Right at onset of the rain
there is a chance for some freezing rain. At this time it appears
that little to no accumulation of ice is expected. Any that does
form should melt quickly as temperatures continue to warm through
the morning hours. Decided to issue an Special Weather Statement covering this. This
should quickly move through the area.

&&

Synopsis...
issued at 328 am CDT sun Mar 29 2015

Well defined short wave moving through central parts of the
Dakotas was moving towards the area. A front associated with this
wave is forecast to move through the area today. A weak wave ahead of
the main wave lead to the development of rain across Iowa. At 3am
these showers were located from Spencer to Harlan to Council
Bluffs. These showers will continue to move to the east
overnight.

&&

Short term...(today and tonight)
issued at 328 am CDT sun Mar 29 2015

Three main forecast challenges in the short term forecast. The
first is the chance for rain today across the area. The next are
strong winds today...that are close to Wind Advisory criteria and
the other is conditional very high GFDI values leading to possible
fire weather concerns. The fire weather concerns will be further
discussed in the fire weather section below.

Precipitation today should move into the area just before sunrise. Hires
models suggest that this initial band of precipitation will be before the
frontal passage. Good agreement between what is going on now and
the the last 5 runs of the hrrr suggests that the current timing
is accurate. Of concern is the possibility of some minor freezing rain
before the warm air can make it in...especially across
northeastern zones of the County Warning Area. Strong S winds will lead to warm air advection and
warm temperatures through the rest of the morning. Overall total rainfall
will be less than 0.10 inches. Clouds will clear out across
western areas of the County Warning Area. This will lead to warmer temperatures
and possibly dry out the area by middle afternoon.

Winds will be close to Wind Advisory criteria this afternoon....especially
in Buchanan...Delaware...Benton and Linn counties. At this time the
current forecast is below Wind Advisory criteria. With winds being
close to advisory criteria...small changes in the forecast could
result in the need for an advisory later.

Clouds should clear out for tonight

Long term...(monday through saturday)
issued at 328 am CDT sun Mar 29 2015

Highlights of the long term period include warmer temperatures through
Thursday and more active weather middle to possibly late week.

The warming trend will continue Monday and Tuesday with highs most
areas in the 60s. Wednesday will likely be the warmest day of the
week...with 850mb temperatures prognosticated around 11-13c ahead of an
approaching cold front...yielding afternoon highs in the middle 60s to
middle 70s.

Confidence is increasing that at least one system will impact the
forecast area during the long term period...although run-to-run
consistency issues Don/T provide much confidence in timing. Have
maintained the highest probability of precipitation for Wednesday night...still supported by
the GFS/Gem. The 29/00z European model (ecmwf) is now slower than previous runs with
the bulk of the rain on Thursday and Thursday night. Depending on
the timing...moisture and instability may be enough for some robust
thunderstorms...although plenty of factors have to come together for
any type of significant severe weather threat this time of year.

Previous runs of the European model (ecmwf) are influencing the lingering chance probability of precipitation
on Friday...although that period may end up being dry. Expect cooler
temperatures Friday and Saturday...with highs in the upper 40s and
50s.

&&

Aviation...(for the 12z tafs through 12z Monday morning)
issued at 647 am CDT sun Mar 29 2015

VFR conditions will persist through the period with precipitation
occurring at the beginning of the period. Cid and dbq could see
some freezing rain in the next hour or two before it changes over to rain.
Mli and brl will see rain. Then the winds will pick up with gusts
close to 40mph this afternoon. Ceilings should go away in the late
afternoon with winds being the major issue for aviation.

&&

Fire weather...
issued at 328 am CDT sun Mar 29 2015

GFDI values across all of our Iowa counties reach the the very
high category this afternoon. While this appears to warrant
attention...rainfall this morning could lead to wet fuels. If fuels
can dry out...then there is a chance for the very high GFDI values
to be realized. It is possible that these conditions could be very
localized so decided to not issue any products other than severe weather potential statement and afd
section on fire weather

Another chance for very high GFDI values appears to be on Monday. Winds
will be gusting into the 25 miles per hour range with min relative humidity values in the
middle 20s. Current forecast suggests that eastern zones of the County Warning Area
could see these conditions. So pay attention to later forecasts
about fire weather.

&&

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

$$

Update...Gibbs
synopsis...Gibbs
short term...Gibbs
long term...rp Kinney
aviation...Gibbs
fire weather...Gibbs

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