Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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836
FXUS63 KDVN 230800
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
300 AM CDT Sat Sep 23 2017

.SYNOPSIS...
Issued at 300 AM CDT Sat Sep 23 2017

Nearly stationary frontal boundary extended from northern/western
MN to near Sioux Falls to Denver. Thunderstorms were occurring
near and west of this boundary. Ahead of the front, another night
of unseasonably warm temperatures with 2 am readings in the 70s.
The exception was the Twin Cities where they were remarkably still
in the lower 80s! Dewpoints were in the mid to upper 60s.

Elsewhere behind the strong frontal boundary temperatures were in
the chilly 30s and 40s across the northern Rockies and into the
western Dakotas.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 300 AM CDT Sat Sep 23 2017

Forecast focus on record highs today.

Today: Another sunny and hot day is in store as the high pressure
surface and aloft remains locked in place. Record highs are in
jeopardy (or at least close to records) at many locations. I will
forecast highs in the lower 90s and with dewpoints in the mid to
upper 60s, this will push heat index values into the mid 90s. 850
mb temperatures will be in the 18-19c range which should support
these hot readings. Once again this will be sorta close to a heat
advisory (which is typically 100-105) but will let the day shift
evaluate the situation. At least a special weather statement may
be needed. Nonetheless, precautions should be taken if spending
time outdoors.

Tonight: Clear skies expected with lows dipping into the mid to
upper 60s, along with a light southeast wind.

.LONG TERM...(Sunday through Friday)
ISSUED AT 300 AM CDT Sat Sep 23 2017

Summer warmth will continue through Monday, and to a certain degree
Tuesday, before a cold front sweeps through with a return to more
normal temperatures in the mid 60s to lower 70s for the rest of
the week.

Sunday and Monday will be a continuation of mostly sunny to partly
cloudy skies, with south to southeast winds.  Both days are expected
to see upper 80s highs, as deep mixing is paired with slightly
cooler mid level temperatures aloft. This deep mix should allow
dewpoints to drop a few degrees during the afternoon hours both
days, and should keep heat index readings only a degree or two
higher than the ambient temperature. Thunderstorms will fire each
day through Tuesday well to the west along the stalled front, just
like what is occurring right now in the Dakotas and Minnesota.
Models have varied greatly on how much activity will move east, and
given the high amplitude flow, I really don`t see why it would
progress east quickly, if at all until Tuesday.  However, it is
close enough that some decaying activity will possibly make it into
the area Monday afternoon and night. Rains will be most possible
west, while the east half should remain dry. The pop blend has
slights east of the Mississippi, and that seems fairly generous.  In
the end, I hope that we can sharpen that gradient and go dry east
until the front passes by Tuesday afternoon.

By Wednesday, all guidance points to post frontal breezy dry
conditions, and very pleasant temperatures.  The dry and cool air
will be in place through Friday, with a small chance for instability
driven showers near our northern counties towards Thursday and
Friday afternoons.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
ISSUED AT 1145 PM CDT Fri Sep 22 2017

VFR conditions with winds under 10kts will prevail through the
forecast period.

&&

.CLIMATE...
ISSUED AT 300 AM CDT Sat Sep 23 2017

Record Highs for September 23...

Moline.........91 in 2007
Cedar Rapids...90 in 1930
Dubuque........91 in 1891
Burlington.....93 in 2007

Record Highs for September 24...

Moline.........91 in 2007
Cedar Rapids...92 in 1984
Dubuque........90 in 1935
Burlington.....91 in 2007

&&

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

$$

SYNOPSIS...Haase
SHORT TERM...Haase
LONG TERM...Ervin
AVIATION...Wolf
CLIMATE...Haase



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