Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

FXUS63 KDVN 151152

Area Forecast Discussion
National Weather Service Quad Cities IA IL
652 AM CDT Sat Oct 15 2016

Issued at 648 AM CDT Sat Oct 15 2016

Cloud ceilings well below 1 kft agl with dropping visibilities
indicate patchy drizzle has or is forming. Mode 31 of the radar
suggests some bands of drizzle moving through the area.

As such the forecast has been updated to reflect some very light
drizzle. Since wind speeds are above 10 mph, the drizzle may or
may not be noticeable.


Issued at 301 AM CDT Sat Oct 15 2016

06Z surface data has high pressure over the eastern Great Lakes with
a cold front moving across the Dakotas. Dew points were in the 40s
across the Great Lakes with 50s and 60s from the upper Midwest into
the southern Plains.


.SHORT TERM...(Today and Tonight)
ISSUED AT 301 AM CDT Sat Oct 15 2016

Satellite trends show the low clouds are making progress moving
northeast into the area. Most of the area should see cloudy skies by

Cloud cover will persist across the area during the morning. The
lack of any forcing should result in dry conditions being seen
through mid day.

This afternoon, forcing is either non-existent or very weak through
late afternoon. Thus dry conditions should persist along with the
clouds. The cloud cover is expected to suppress temperatures
somewhat so highs have been lowered for today.

Starting around sunset forcing increases as an upper level
disturbance moves across Iowa. Isolated showers should break out
across much of eastern Iowa that will quickly increase in coverage
during the early evening. As forcing increases after sunset,
thunderstorms will also develop.

Thunderstorm coverage will maximize during the mid evening hours up
to roughly midnight. After midnight, the stronger forcing will move
east of the area allowing the thunderstorm coverage to decrease and
the rain to slowly end from west to east.

Once thunderstorms develop this evening, the possibility does exist
that some storms may become strong. Given the dry air aloft, hail
will be a possibility in the stronger storms along with gusty winds.
As the evening hours progress, storms should become more elevated
with time. Once storms become elevated, the hail threat may persist
but the wind threat will decrease.

.LONG TERM...(Sunday through Friday)
ISSUED AT 301 AM CDT Sat Oct 15 2016

Sunday, we will be seeing strong waa through the day. The question
on how warm we get is much like today, where cloud cover may hold on
through much of the day, resulting in a warm bias in models forecast
highs Sunday. I find it hard to imagine highs in the upper 70s to
lower 80s occurring without strong winds and full sun, but that is
what models are suggesting. I have decided to undercut guidance for
highs and go with mid 70s north to lower 80s south. This may still
be 5 degrees too high if cloud cover does not thin during the
afternoon. Rain showers should be east of the CWA by very early in
the day.  Winds appear more likely to remain south to southeast
Sunday, one more factor to consider in highs falling short of model

Monday, however is a different story. Extremely mild air will be
found just aloft, and with southwest winds through the day, we are
in a favorable position for a very warm high temperature, along with
breezy conditions and partly cloudy to mostly sunny skies. Highs in
the lower to upper 80s from north to south are likely. Normally, I
would see a fire weather threat on such a day, but models insist
dewpoints will remain in the lower to mid 60s, with afternoon RH
values around 50 to 60%.  Thus there should be not be a high fire

Monday night, a dry fropa is expected toward morning, with cold
advection lagging well behind the front. This especially true on the
GFS and GEM solution, but the ECMWF is far stronger with the cold
front. This is the first major difference in the 00z models, and
from that point, they are not just on different pages, it`s a
different book in a different language. The GFS and GEM cut off a
large upper low, and bring widespread cold rains to the upper
midwest through the Wednesday through upcoming weekend period, while
the EC sweeps the Tuesday cold front south, and keep it there.
Therefore the synoptic wave it develops rides up the Appalachians
while we see a wintry airmass spread over the the region. 850mb
temperatures of -2 to -4 spread south through Iowa.  The 00z GFS
does have cold air into Minnesota, but does not bring it south and
east, as the upper low spreads warmer air into the Great Lakes
region as it occludes. No doubt the extended model blended solution
we are initializing with will not reflect either of these solutions,
but in general, we will need to watch this period for significant



.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
ISSUED AT 638 AM CDT Sat Oct 15 2016

IFR/LIFR conditions across Iowa and northern Illinois should
slowly improve to MVFR through 18z/15. After 23z/15 MVFR
conditions will continue with areas of IFR conditions as TSRA
develop. After 05z/16 widespread MVFR to IFR conditions will
overspread eastern Iowa and northern Illinois.




AVIATION...08 is the U.S. government's official web portal to all federal, state and local government web resources and services.