Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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368
FXUS63 KDVN 240849
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
349 AM CDT TUE MAY 24 2016

.SYNOPSIS...
Issued at 330 AM CDT Tue May 24 2016

An area of showers and embedded thunderstorms moved into central
Iowa during the early morning hours, and was approaching eastern
Iowa. High level cloud cover persisted into the early morning
hours.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT Tue May 24 2016

The main issues in the short term period are shower/thunderstorm
coverage, intensity and timing.

In the near term, an area of showers and embedded thunderstorms
has pushed into the far eastern fringe of the forecast area. Have
made some late adjustments to hourly pops and weather and more
frequent updates will be needed through daybreak. Virtually the
entire forecast area is in the SPC marginal risk area today. The
threat for any organized severe weather is low due mainly to weak
deep layer shear. There could be a few strong storms, with some
CAMS highlighting the Highway 20 corridor later this afternoon and
evening. Other than the early morning pop adjustments, have
generally lowered pops from mid-morning on. Today will not be
quite as warm as Monday with more extensive cloud cover, although
afternoon highs should remain above normal, generally in the 80 to
83 degree range.

For tonight, convective trends remain unclear with a broad
spectrum of model solutions. Some models hint at a late night MCS
which could impact portions of the forecast area. For now, will
not stray from the model blend QPF, which favors the southwest
counties for a more organized complex. The main threat would be
locally heavy rain.

.LONG TERM...(Wednesday THROUGH Monday)
ISSUED AT 330 AM CDT Tue May 24 2016

Forecast focus on an active pattern with several rounds of showers
and thunderstorms but also many dry hours in between. There is also
the potential for strong to severe thunderstorms and locally heavy
rainfall.

Rather stagnant/blocky synoptic pattern during the entire extended
with a deep trough anchored in the Rockies and a ridge in the east.
The main dynamics and stronger forcing/shear should remain out in
the Plains so the bulk of the severe weather is expected to be west
of the DVN cwa, perhaps spilling into our western counties. The
models are really muddled in this pattern with constant showers and
thunderstorms for days and days. However, this is usually not the
case so timing the individual short waves and associated
thunderstorms is difficult, especially as you go out in time.

Therefore, we will continue with chance to likely pops through at
least day 7 and the models suggest this blocked pattern should
continue well into next week too. Temperatures will remain above
normal with many days in the 80s and lows in the 60s. Believe the
dewpoints are too high especially with the GFS/NAM depicting
dewpoints in the 70s (considering crops are only in their early
stages of growth). ECMWF is better with dewpoints mainly in the 60s
and this is climatologically favored.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Tuesday NIGHT)
ISSUED AT 1119 PM CDT Mon May 23 2016

VFR conditions to generally VFR conditions to prevail the next 24+ hours.
Clouds will slowly increase tonight with any bases aoa 4k agl as a plume
of moisture from the gulf arrives late overnight into Tuesday. Isolated
to scattered coverage of showers and storms will slowly arrive at the
terminals from west to east after 24/09z and last through Tuesday morning.
Coverage at this time warrants tempo late overnight into mid Tuesday
AM. Then removed vicinity wording afterwards due to poor confidence
and coverage issues. Possible another chance of showers and storms may
redevelop Tuesday evening. The strongest showers and storms may reduce
visibility briefly to mvfr conditions this morning.

&&

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

$$

SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...Haase
AVIATION...Nichols



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