Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 230855

Area Forecast Discussion
National Weather Service Quad Cities IA IL
355 AM CDT Fri Jun 23 2017

Issued at 319 AM CDT Fri Jun 23 2017

At 07z the main synoptic cold front extended from southern WI
through our northwest CWA including DBQ and CID on southward
into E KS. Showers and storms extended along and ahead of the
front shifting e/se and are likely to exit the far southeast
CWA by 12z-14z. In the wake of the front notably cooler and
drier conditions were being found from the Northern Rockies
into the Upper Midwest. Deepening northwest flow looks to usher
this cooler and drier airmass into our region through the weekend.


.SHORT TERM...(Today and Tonight)
ISSUED AT 319 AM CDT Fri Jun 23 2017

Cold front to exit prior to mid morning taking any showers and
storms with it. Gusty north winds post frontal will continue to
usher in drier and cooler air. Decreasing clouds is expected to
occur this morning, but by afternoon colder air aloft should
contribute to steepening lapse rates and foster cumulus clouds
with more notable coverage over the northern CWA (closer
proximity to H7-H5 cold pocket and strong cyclonic flow) where
a stray brief shower can`t be ruled out mid to late afternoon.
Banking on ample solar insolation and deeper mixing to see temps
recover mostly into the middle 70s to around 80 degrees for highs.

Tonight, with mainly clear to partly cloudy skies and diminishing
winds will see comfortable lows in the 50s.

.LONG TERM...(Saturday through Thursday)
ISSUED AT 319 AM CDT Fri Jun 23 2017

Large and fairly deep polar trough looks to become established
this weekend through early next week from the Great Lakes
region through eastern Canada. NAEFS standardized anomalies for
this incoming airmass at H85 are 2 to 4 standard deviations
below normal by 00z MON with return intervals of every 2 to 5
years, denoting an unseasonably cool airmass. One that may
harbor some record cool in spots if standard deviations of
3+ below normal occur, especially in/around the Great Lakes
region. Highs will likely be in the 60s and 70s SAT-MON with lows
in the upper 40s to mid 50s.

One potential fly in the ointment is the risk of a few afternoon
showers on Saturday across the north with a fairly strong,
compact PV anomaly, and shower chances return again on Sunday PM
mainly north with cold temps aloft and CVA. Neither should cancel
any outdoor activities.

Heading toward mid to late next week is showing signs of
significant pattern change toward a warmer and more unsettled
period, as the flow aloft turns fast zonal. Meanwhile, at the
surface developing and strengthening southerly winds look to
transport moisture northward and should combine for a period of
storminess with one or more convective complexes on the edge of
the heat dome to our southwest.


.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
ISSUED AT 1132 PM CDT Thu Jun 22 2017

At least scattered coverage of thunderstorms is anticipated to persist
overnight ahead of a cold front. Have gone with tempo wording at
most TAF sites trying to target a 2 hour window of highest probability
ahead of the northerly wind shift prior to 12z. Some guidance
continues to suggest MVFR to possibly IFR ceilings in the wake of
the storms and cold frontal passage. While lower conditions can`t
be ruled out given ample low level moisture and cool advection I have
left out any mention as confidence too low given lack of lower ceilings
post frontal per latest obs. Northerly winds may occasionally gust to
around 20 kts on Friday by mid morning through afternoon before
diminishing with sunset, as conditions remain VFR during this timeframe.




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