Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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423
FXUS63 KDVN 271155
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
555 AM CST Mon Feb 27 2017

.UPDATE...
Issued at 554 AM CST Mon Feb 27 2017

Have issued a special weather statement through 8 am for locally
dense fog across portions of extreme southeast IA, extreme
northeast MO and into far western IL. This area has had clear
skies, light winds and better moisture convergence during the
night. Believe that as the sun rises within the hour the winds
will begin to increase and the fog should dissipate. However,
will continue to monitor trends early this morning.

Meanwhile, a band of mid deck clouds was persistent in eastern IA
roughly between I-80 and Highway 20.

&&

.SYNOPSIS...
Issued at 345 AM CST Mon Feb 27 2017

A band of mid level clouds was lifting northward across our
northern cwa while clear skies were noted in our south.
Temperatures were in the mid 20s to lower 30s.

Elsewhere, dense fog was widespread in northern and central MO but
was still south and west of the dvn cwa.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 345 AM CST Mon Feb 27 2017

Forecast focus on showers and scattered thunderstorms tonight.

Today: Mostly sunny skies can be expected for most of the day, and
along with southerly winds, this should be a warmer day. Highs
should range from the upper 40s along Highway 20, to the upper 50s
in our southern cwa. By late in the afternoon, mid level clouds
will be on the increase due to strengthening mid level warm air
advection. This will be occurring as cyclogenesis takes place in
eastern CO.

Tonight: A strengthening southerly moisture transport will be
evident as low pressure tracks to near Omaha by 6 am Tuesday, and
a warm front lifts northeast across the cwa. Forcing increases
due to low level convergence on the nose of a strong 50 kt low
level jet. Showers and scattered thunderstorms should develop this
evening in our southern cwa and then spread across the remainder
of the area overnight. While deep layer shear is strong,
instability is minimal and severe weather is not expected. SPC has
the entire cwa in general thunder. However, with the freezing
level at 7-8K FT small hail certainly seems likely in any stronger
storm, and may cover the ground at some locations. Minimum
temperatures will be in the 40s to around 50.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 345 AM CST Mon Feb 27 2017

Main focus is on the potential for severe weather and possible
record highs Tuesday. Otherwise, a change to cooler and more typical
early March weather featuring highs in the 40s and lows in the 20s
follows for mid to late week under a NW flow. A more zonal pattern is
shaping up for next weekend, sending highs back into at least the
50s. A low confidence clipper system may bring light precipitation
late Thursday, otherwise, most of the late week and weekend
periods look dry.

Tuesday: The surface warm front is likely to be north of the area
with ongoing showers and possible thunderstorms in the north during
the morning. In the south, deeper mixing on gusty south to southwest
winds will drive temperatures well into the 60s, if not near 70 in
the far south. Highs will come close to February 28 record values,
which are referenced in the climate section. A more critical period
will be from mid afternoon into evening over the southeast half of
the forecast area, where deep shear, and to a lesser extent,
instability will set the stage for possible severe thunderstorms.
SPC has a day 2 slight risk reaching into our far SE IL counties and
a marginal threat for roughly the southeast half of the forecast
area. While there remain considerable timing differences among the
models, the overall setup with a 100 to 120 kt upper level jet
advancing into the far south, frontal passage late in the afternoon
advancing into a warm sector with dewpoints at least into the 50s
and low level CAPE possibly pushing 1000 to near 1500 J/KG ,and
nearly 50 kts of zero to 3 km bulk shear, this will be a period that
will need to be watched closely and for now have gone with likely
thunderstorm wording. Heavy rainfall with stronger thunderstorms may
also be an issue and some models are pushing out convectively
enhanced QPF bullseyes of 1 to 1.5 inches Tuesday evening.

Tuesday night into Wednesday, cold advection commences on brisk nw
winds with a possible additional wave of rain overnight, then rain,
changing to snow showers ending Wednesday afternoon from NW to SE.
Overall, forecast confidence is low for this period with
precipitation in the models likely overdone.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
ISSUED AT 554 AM CST Mon Feb 27 2017

Mainly VFR conds today then low pressure moving into the central
Plains tonight will spread showers and scattered thunderstorms
across the taf sites, with MVFR/lcl IFR conds developing. This
activity should begin in our southern counties this evening and
spread to the northeast overnight. For now didn`t include thunder
in the TAF`s but later shifts can add when confidence becomes
better with regard to coverage and timing of convection. South to
southeast winds increasing to 10 to 15 knots later today and
continuing tonight.

&&

.HYDROLOGY...
Issued at 345 AM CST Mon Feb 27 2017

Many area rivers are on the rise due to recent rainfall and
snowmelt. Along the tributaries, a flood warning remains in effect
for the Cedar River near Conesville, where the river is expected to
crest around one half foot above flood stage on Tuesday. This
forecast has remained somewhat consistent over the past several days
with a minor trend of delaying and slightly lowering the flood crest
based on upstream trends. Elsewhere, no flooding is currently
forecasted. However, these forecasts do not incorporate forecast
rainfall from the early week system. This, along with an anticipated
rapid melting of the snowpack in the upper reaches of the river
basins will likely result in renewed rises and possible flooding out
7 to 10 days.

More significant rises and possible flooding is forecast for
segments of the Mississippi River due to routed flow. Flood watches
remain in effect for numerous points from Dubuque to Burlington for
potential flooding forecast to begin later this week into the weekend.

&&

.CLIMATE...
ISSUED AT 345 AM CST Mon Feb 27 2017

Record Highs for February 28...

Moline.........66 in 2016
Cedar Rapids...64 in 1932
Dubuque........62 in 1895
Burlington.....69 in 1932

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

UPDATE...Haase
SYNOPSIS...Haase
SHORT TERM...Haase
LONG TERM...Sheets
AVIATION...Haase
HYDROLOGY...Sheets
CLIMATE...Sheets



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