Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 151959
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
259 PM CDT Sun Apr 15 2018

.SYNOPSIS...
Issued at 259 PM CDT Sun Apr 15 2018

Upper level low rotating across eastern Iowa and Illinois led
to light snow across the region for much of the day. Snow
accumulations of 1 to 2 inches on grassy and elevated surfaces
were observed across portions of eastern Iowa and northwest
Illinois, with little to nothing elsewhere. Temperatures ranged
from the upper 20s to middle 30s as of 2 PM; which is
approaching 30 degrees below normal for the middle of April!
(Highs average in the upper 50s to middle 60s for April 15th)

&&

.SHORT TERM...(This Evening through Monday)
ISSUED AT 259 PM CDT Sun Apr 15 2018

Primary concerns in the short term is the system leaving the area
and cold temperatures tomorrow. Even though much of the forcing is
leaving the area, cloud cover will remain across the area
tomorrow, leading to cooler high temps.

Vort maxs rotating around the filled low continued light snow
across the region this afternoon. The upper level low will slowly
lumber east through the overnight hours. Hires guidance has
consensus of light snow across the area. This light snow is
expected to continue across the eastern CWA through daybreak.
Overall forcing will weaken leading to a decrease in the intensity
of precip through 12z. As a result, overall QPF amounts will be
low across the area.

Tomorrow, winds will pick up again and temps will struggle to
reach 40 degrees across the southern CWA. Increased sky cover to
near 100% through most of the day. It appears that the MOS
guidance appears to be too high, relying too much on the climo
part of the stats. As such, shied away from mos for temps.

.LONG TERM...(Monday Night through Sunday)
ISSUED AT 259 PM CDT Sun Apr 15 2018

Models continue the trend of cold temps through most of the work
week. Only modest warm ups are forecast through the end of the
period as largescale flow remains rather NW. Short ridging before
the next system will aide in bringing temps above freezing,
leading to a mainly cold rain event. Another system for the
weekend, has most of the precip south of the area. However temps
look to be in the 50s for the next weekend system precluding any
threat of frozen precip.

The next system will have a quick moving H5 wave into the area for
Wednesday AM. As usual with the guidance, the dprog/dt in the
models are for a slower moving system. The 12z GFS currently has
QPF across IA through 12z on Wednesday. However, this seems to be
the fastest guidance and overall an outlier. As a result,
superblend gave pops well into the area from 06z to 12z Wednesday.
With the cold surface temps, fzra was suggested by the init. This
does not seem reasonable, as such slowed down the arrival of pops
Wed AM. This will limit overall fzra chance. There will be a
chance for FZRA Wed AM, especially at onset of precip across the
hwy 20 corridor. Impacts from this are expected to be very low
and temperatures will warm quickly as H85 WAA overtakes the area.
Overall another snow event is forecast north of the area
Wednesday, while we sit with cold rain. This time around most of
the QPF will be associated with the WAA band, this band is best
north of the CWA.

The rest of the week begins to warm up. However, this warm up will
be below average for highs. Into this weekend, there is another
system that is consistently been forecast to move south of the
area. While this seems reasonable, do have a concern that the best
baroclinicity will be close to the snow pack. This may mean that
the system may track north. We will need to keep an eye on this
for next weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
ISSUED AT 630 AM CDT Sun Apr 15 2018

Generally MVFR to IFR conditions expected through the TAF period,
as an upper level low pressure system moves slowly over the
region. This system will bring periods of a light wintry mix
changing to snow today, with a glaze of ice and snow accumulations
of 1 to 3 inches north/west of the Quad Cities. Bouts of light
snow will taper off to mostly flurries later tonight lingering
into Monday. Gusty northeast winds 15-30 kts will shift to northwest
by tonight.


&&

.CLIMATE...
ISSUED AT 217 PM CDT Sun Apr 15 2018

Record Lows for April 16...

Moline.........19 in 1875
Cedar Rapids...17 in 1949
Dubuque........14 in 1875
Burlington.....22 in 1949

Record Lows for April 17...

Moline.........18 in 1875
Cedar Rapids...22 in 1997
Dubuque........16 in 1875
Burlington.....23 in 1907

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory until 7 PM CDT this evening for Benton-
     Buchanan-Delaware-Dubuque-Jackson-Jones-Linn.

IL...Winter Weather Advisory until 7 PM CDT this evening for Jo
     Daviess-Stephenson.

MO...NONE.
&&

$$

SYNOPSIS...Speck
SHORT TERM...Gibbs
LONG TERM...Gibbs
AVIATION...McClure
CLIMATE...Gibbs



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