Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 47 48 49 50
000
FXUS63 KDVN 210831
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
331 AM CDT WED SEP 21 2016

.SYNOPSIS...
Issued at 304 AM CDT Wed Sep 21 2016

Analysis at 3 AM CDT depicts a MCS system over triangle of WI/IA/MN
moving ESE that will miss or just glance far NE parts of forecast area
by 21/12Z. Upstream energy shows bouts of showers and storms likely
next 24 hours mostly or all north of forecast area. Low level thermal
fields supports with mostly sunny skies with near record warmth with
a better chance of showers and storms in NW sections of area tonight.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 304 AM CDT Wed Sep 21 2016

Short term forecast confidence assessment...poor or below average. Main
issue is area dewpoints today that likely are 2 to 4+ degrees too high
that will result heat indices several degrees lower than forecast. Then
issue will be where next MCS fires late PM today and impacts on area
tonight.

Today...partly to mostly sunny south and partly sunny to mostly cloudy
in high clouds today. Area highs should be within 5 to 7 degrees of
records with middle 80s far N/NE sections and upper 80s to around 90
degrees elsewhere. Winds will be southerly at 5 to 15+ MPH. Area dewpoints
are currently forecast to reach near 70F in many parts this PM but trends,
lots due to dying vegetation suggest dewpoints may be more in mid to
upper 60s most locations resulting PM heat indices about 3 to 6 degrees
lower than forecast. Have low POPS north today that may be too high
if MCS to our north misses us completely next 3 to 4 hours.

Tonight...Increasing clouds and unseasonably mild with mins mid to
upper 60s. Main concern is POPS that may be too low by late evening
and overnight in NW 1/2 or more of the area. If MCS does pass then area
rainfall amounts of .5 to 1.5 inches may be common for later shifts
to reassess. This should not cause significant water problems but another
episode may occur after tonight.

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 304 AM CDT Wed Sep 21 2016

Internally, the models are suggesting an organized thunderstorm
complex will move across the northwest parts of the area in a
decaying mode Thursday morning. Boundaries left over from this
complex will then provide the focus for new convection that develops
across the northwest third of the area Thursday afternoon. Cloud
cover and rain Thursday will dictate temperatures but most of the
area should see above normal temperatures Thursday.

Thursday night/Friday, another organized thunderstorm complex will
develop and potentially affect the northern two thirds of the area.
The better rain chances look to be generally along/north of highway
30.

Currently, most model solutions indicate Friday night will be dry
across the area as the warm front moves north into Wisconsin.
Temperatures will average above normal.

Saturday on...

Dry and very warm conditions will be seen across the area on
Saturday. Temperatures will be well above normal. Attention then
turns to the system ejecting out of the desert southwest.

All the global models eject a significant upper low out of the
desert southwest late this week and into the weekend. How the energy
from the desert southwest interacts with additional energy topping
the ridge in the eastern Pacific will dictate the sensible weather
for the area.

Right now the model consensus has slight chance to chance pops
Saturday night, then chance pops Sunday through Monday, followed by
slight chance to chance pops Monday night and Tuesday.

It is very possible that the upper low in the desert southwest will
eject slower than what the models indicate. If this occurs then
Saturday night and possibly Sunday may be dry.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
ISSUED AT 1117 PM CDT Tue Sep 20 2016

Warm southeast winds will continue through the period, with
mainly VFR conditions except for some possible morning MVFR light
fog expected sites in southeast Iowa. The north, along with
northeast Iowa, will see a chance for a thunderstorm complex
arriving after 3 AM tonight, and lasting through the mid morning
hours. This may or may not occur, as the track is uncertain at
this time. I did put in a tempo group at DBQ to cover this threat
since they are the most likely to see storms. Otherwise, the main
rain and thunderstorms in the region should stay in southern
Minnesota and Wisconsin.

&&

.HYDROLOGY...
Issued at 304 AM CDT Wed Sep 21 2016

MROI4 is in the process of cresting with DEWI4 near crest. CNEI4 is
rising again toward a second crest above flood stage.

Current trends indicate most of the area should see dry conditions
for another 12 hours before any rain comes into the picture. This
may be just enough time to allow MROI4 and DEWI4 to crest and start
falling.

The overall weather scenario points to above normal rainfall for the
next 48 to 60 hours across the upper Midwest. This rainfall will be
associated with organized thunderstorm complexes that may result in
excessive rainfall. The upper parts of the Iowa, Cedar, and
Wapsipinicon basins may potentially get hit hard with heavy rain.
Other basins such as the Maquoketa may get hit hard as well.

This prolonged rain event will result in the above mentioned rivers
to start rising again over the weekend and into next week. The
location and amount of rainfall will dictate the potential for any
river flooding next week.

&&

.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.

&&

$$

SYNOPSIS...Nichols
SHORT TERM...Nichols
LONG TERM...08
AVIATION...Ervin
HYDROLOGY...08



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