Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 211759

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1259 PM CDT Fri Oct 21 2016

Issued at 100 PM CDT Fri Oct 21 2016

High pressure ridge over the dvn cwa providing full sunshine and
light winds this morning into early this afternoon. Highs in the
50s still look on track based on current trends.

Watching 2 areas of clouds, one area of low clouds streaming
southward off Lake Superior and covering much of central and
eastern WI and edging into northern IL. The other area is warm air
advection mid/high clouds pushing southeast across MN, western
half of IA and the eastern Dakotas.

Expecting these clouds to continue spreading into the dvn cwa
as the afternoon progresses and remain over much of the area into
tonight. Despite our far eastern counties having light wind most
of the night, the clouds should prevent a widespread frost so will
keep the mention of patchy frost going in the grids. Elsewhere,
winds become southerly overnight with warmer temperatures there.
At this time not anticipating any frost headlines to be issued.

UPDATE Issued at 833 AM CDT Fri Oct 21 2016

With temperatures beginning to rise the frost advisory has been
allowed to expire at 8 am. Widespread frost has been reported
early this morning across much of the cwa.


Issued at 315 AM CDT Fri Oct 21 2016

Sfc high pressure ridge axis currently stretching from western
Ontario through the Upper Mississippi River Valley into the
Southern Plains. Gradual eastward progression will take place
through today. 3 AM temps were in the mid 30s to near 40 F across
E Iowa/NW Illinois - close to mid October avg lows. Should drop
another 2-4 F degrees most areas into early this morning.


.SHORT TERM...(Today and Tonight)
ISSUED AT 315 AM CDT Fri Oct 21 2016

Today and Tonight...A cool fall day to end the work week in the
mid 50s. Winds will be light but highest in the east where
daytime mixing may allow gusts near 15 kts out of the NNW. Threat
for frost carries over into tonight, especially NE/E CWA with
forecast lows in the mid 30s. Will let day shift make decision on
whether or not new frost advisories are needed. Thinking setup is
less favorable. WAA at 925-700mb possibly brings in
scattered/broken low/mid clouds and sfc winds develop out of the
south in newly formed sfc pressure gradient. Uttech

.LONG TERM...(Saturday through Thursday)
ISSUED AT 315 AM CDT Fri Oct 21 2016

Fairly benign and splendid fall weather on tap this weekend into
then beginning of next week. The weather then turns unsettled toward
and around the midweek timeframe.

This weekend an upper level ridge will temporarily flatten with the
pattern aloft turning northwesterly by late in the weekend, as an
upper level shortwave traverses the Canadian border before diving
southeast through the Great Lakes into a persistent eastern conus
trough. With gulf moisture cut off by surface high pressure, and
limited pacific moisture entrained by shortwave largely staying to
our north/east... expect mostly fair skies and dry conditions
through the weekend. Highs will also be above average and warming
from the 60s Saturday to well into the 60s and lower 70s on Sunday.

Early next week the upper level ridge will reamplify over the central
conus ahead of a western trough. This will maintain dry and seasonal
temperatures for the area Monday into Tuesday.

Later Tuesday through Wednesday will see the ridge break down as a
low amplitude shortwave ejects from the western trough and move
across the Central Plains and Mid-Mississippi Valley. A 30-35+ kt
low level jet will quickly bring a return of moisture with
precipitable water values surging over an inch to near 1.5 inches by
Wednesday. At least moderate forcing with wave and surface cyclone
and easterly flow north of warm front supports a swath of moderate
to potentially locally heavy rain in or near our cwa, with at least
isolated to scattered embedded thunder. Details on the magnitude of
any storms this far out still difficult to assess. Temperatures will
be difficult especially Wednesday due to location and movement of
warm front and attendant precipitation, but where this sets up
could see some areas struggle to reach 50 degrees north of the warm

Late next week looks to see warming temperatures back to normal or
slightly above. Some significant timing and pattern differences
between GFS (shortwave and troughing from Great Lakes to Mid-
Mississippi Valley) and ECMWF (ridging) by late next week lends to
low confidence day 6-7.


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
ISSUED AT 100 PM CDT Fri Oct 21 2016

VFR conds through this taf cycle as high pressure ridge shifts
southeast away from the area. Northwest winds this afternoon
becoming variable tonight, then south on Saturday. Wind speeds
around 10 knots or less through this taf period.




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