Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 222348
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
648 PM CDT Sun Apr 22 2018

...00z AVIATION UPDATE...

.SYNOPSIS...
Issued at 327 PM CDT Sun Apr 22 2018

Dry and mild conditions were found across the area this afternoon
with temperatures averaging near to above normal for a change,
from the 60s to around 70 at 3 pm. A brisk low level easterly
flow was being maintained by the pressure gradient between high
pressure over the Great Lakes and a passing low pressure system
moving through the lower MS River Valley. The very dry airmass had
dewpoints largely in the 20s over the forecast area. High cloud
cover spewing off the storm system to the south was much thinner
and more scattered compared to yesterday.

&&

.SHORT TERM...(This Evening through Monday)
ISSUED AT 327 PM CDT Sun Apr 22 2018

Little change in sensible weather is expected tonight through
Monday. The storm system to the south, in the form of a large,
slow moving upper level low, will continue to slowly progress
eastward. This will maintain the low level easterly winds, which
will back to the northeast as the surface low meanders into the
Ohio River Valley, keeping the dry Great Lakes airmass in place.
Associated high level cloud cover will also continue to be more
widespread over the south and southeast, favoring clear to partly
cloudy skies in the north and northeast.

Tonight, the thinner cloud cover should lead to cooler lows than
last night and have gone with upper 30s north to lower 40s in the
far south. The sustained light easterly winds, veering to the
northeast will also prevent the possibility of much cooler
temperatures that would be otherwise be possible due to the very
dry air. Monday will be similar to today, with more sunshine in
the north and periods of scattered to overcast high clouds in the
south. Have again gone near to above the warmest guidance, from
the mid 60s to around 70, due to the sharper diurnal trends, not
handled well by models that have consistently been overly too
moist at the surface the past couple days.

.LONG TERM...(Monday Night through Sunday)
ISSUED AT 327 PM CDT Sun Apr 22 2018

Long Term forecast Confidence Assessment...fair to good or average
to above average.  Limited sensible weather issues indicated with a
chance of rain or rainshowers and possibly embedded non-severe
storms late Wednesday the most notable item. Temperatures to
continue to be mostly near to below normal for days 2-7, though not
as below normal as the past several weeks have been.

Tuesday through Wednesday...generally fair to partly cloudy and dry
with near to slightly below seasonable temperatures.  Highs mostly
60s Tuesday and then 55 to 65 Wednesday.  Lows mostly in the 35 to
45 degree range.  Average climatology is highs in the mid/upper 60s
with mins in the lower/middle 40s for days 2-7.

Thursday...a fast moving cold front from Canada to pass with limited
moisture available supports isolated storms with very low to nil
instability with projected MUCAPE AOB 500 J/KG.  Highs mostly in the
60s with mins Thursday night 35 to 45. Any rainfall totals should be
mostly light. Possibly some small hail may be feasible but that will
take another 24-36 hours to clarify.

Friday though Sunday...mostly dry and cool early with a warming
trend by Sunday. Highs mid/upper 50s Friday rising into the
mid/upper 60s by Sunday. Mins mostly 30s Friday night and 40s
Saturday and Sunday night.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
ISSUED AT 645 PM CDT Sun Apr 22 2018

VFR level clouds will continue to circulate around a lower MS
RVR/TN Valley low pressure system, and acrs much of the area
tonight into Monday. The pressure gradient off this system will
keep persistent east to northeast sfc winds of 5-10 KTs going
overnight into Monday as well. Good VSBYs to continue through the
TAF cycle, with precip chances off to the south and east.  ..12..

&&

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

$$

SYNOPSIS...Sheets
SHORT TERM...Sheets
LONG TERM...16
AVIATION...12



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