Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 212326
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
626 PM CDT Thu Sep 21 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 230 PM CDT Thu Sep 21 2017

Temperatures have been slow to rebound this afternoon as clouds
from last and this mornings storms have just started to completely
burn off. At the surface the flow has turned southerly and low
level moisture and the effective warm front has surged north of
the area into central MN and N Wisconsin. Winds have been gusty
this afternoon as mesoscale features from storms last night remain
across the area. Through the short term, high pressure will be the
primary weather driver.

&&

.SHORT TERM...(This Evening through Friday)
ISSUED AT 230 PM CDT Thu Sep 21 2017

Main forecast concern through the short term are the temperatures
tomorrow and the chance for any fog development near sunrise. With
locally heavy rainfall and lighter winds across the area could see
some patchy fog tonight. NCAR 3km ensemble has virtually no chance
for fog tonight. I believe guidance is off and there is a better
chance for at least patchy fog. This will need to be monitored by
the next shift.

Focus now shifts to temperatures tomorrow. It appears that current
forecast temps are just below record highs tomorrow. No guidance
is forecasting breaking highs. Temps will be above average for
sure.

.LONG TERM...(Friday Night through Thursday)
ISSUED AT 230 PM CDT Thu Sep 21 2017

Highly amplified longwave upper trough-ridge pattern over the
contiguous U.S. will not begin to break down until early next week.
Prior to that pattern change, unseasonably warm conditions will
persist through next Monday or Tuesday for areas beneath the ridge.

For Saturday through Monday, went slightly above SuperBlend for max
temps because model 850mb temps are in the mid to upper teens
Celsius and daytime mixing should lower sfc dewpoints into the low
to mid 60s. Although quite high for the end of September, dewpoints
in the 60s should prevent heat indices from peaking more than a few
degrees above the ambient air temps.

A cold front will push through E Iowa/NW Illinois during the Tuesday-
Wednesday time frame, causing temps to drop to near normal and
bringing a chance for scattered showers and storms. However, the
front is expected to be in a weakening phase as the stronger upper
dynamics track well to the north over Lake Superior and Ontario. For
this reason, PoPs are only in the 20-40% range and the threat for
widespread significant rain is low. Uttech

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 623 PM CDT Thu Sep 21 2017

VFR conditions will be seen through 06z/22 as an upper level high
develops across the Midwest. After 06z/22 patchy fog may develop
prior to sunrise that may result in some MVFR conditions. After
15z/22, VFR conditions are expected.

&&

.CLIMATE...
ISSUED AT 230 PM CDT Thu Sep 21 2017

Record Highs for September 22...

Moline.........95 in 1937
Cedar Rapids...94 in 1930
Dubuque........92 in 1937
Burlington.....94 in 1937

&&

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

$$

SYNOPSIS...Gibbs
SHORT TERM...Gibbs
LONG TERM...Uttech
AVIATION...08
CLIMATE...Gibbs



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