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Area forecast discussion 
National Weather Service Green Bay WI
315 am CDT Friday Jul 31 2015

Forecast discussion for routine morning forecast issuance

Short Saturday
issued at 238 am CDT Friday Jul 31 2015

Today will be a lot like yesterday in that we will start out with
mostly sunny skies...with fair weather cumulus clouds developing
during the afternoon as a shortwave...currently seen on water
vapor imagery over Saskatchewan...tracks through the up of
Michigan. However unlike yesterday this shortwave will not be as noted by the lack of development associated with
it...and instabilities will be much less than yesterday...on the
order of 100 to 200 j/kg. Also of note is the lack of development
with the hi-res runs and nwp models...with at best an isolated
shower or two across the far northern County Warning Area. Therefore will maintain
the slight chance probability of precipitation across the far north as confidence is much
lower in anything developing today. The tight pressure gradient
will maintain breezy conditions today with highs a degree or two
below yesterdays highs.

The chance for rain will dissipate rapidly overnight with the loss
of daytime heating. Light winds and clear skies will allow for
radiational overnight lows fall into the 50s away
from the Lakeshore.

Saturday looks to be fairly dry as shortwaves track a bit further
north with little to no instability across north central Wisconsin
during the afternoon hours. Highs will once again be similar to
the last few days with highs in the upper 70s to lower 80s.

Long term...Saturday night through Thursday
issued at 238 am CDT Friday Jul 31 2015

The latest ensemble guidance continues to point towards middle-level
ridging build over The Rockies next week...which will place the
western Great Lakes region within northwest flow aloft. The
operational models are in good agreement through 00z Tuesday...including
with the passage of a cold front on Sunday night. Thereafter...will
lean on the European model (ecmwf).

Saturday night through Sunday night...backing low to middle-level flow
on Saturday night will try to bring in warmer and more humid air
into the region. Models last night were bringing widespread showers
and thunderstorms across areas south of Route 29 last night...before
trending southward with their 12z runs. But the latest runs bring
precipitation back northward late Saturday night. Will raise precipitation
chances only slightly as confidence is not that high. Northern
Wisconsin will be located between this warm advection zone over the
southern part of the state and a cold front dropping south over Lake
Superior on Sunday. The close proximity of both features makes it
difficult to remove precipitation chances...but will keep them low. The
cold front moves south across the region Sunday night...and bring
widespread rain chances.

Rest of the forecast...the front is projected to clear the forecast
area by the start of Monday morning. Cooler and drier air will move
in behind the front. But potential is there for channeled
shortwaves to move across the northern part of the state Monday and
Tuesday to generate shower and thunderstorm activity...mainly during
the afternoons. No significant features for Wednesday or Thursday
as temperatures remain slightly below normal. Perhaps the next
chance of rain arrives on Friday.

Aviation...for 06z taf issuance
issued at 1139 PM CDT Thursday Jul 30 2015

Expect mostly VFR conditions through Friday evening. Scattered
showers in cyclonic flow across northeast Minnesota and western
Ontario could impact far northern Wisconsin but think that there
will be little or nothing on the Wisconsin side of the border.
VFR ceilings will probably develop across northern Wisconsin along
with isolated/scattered showers...but the odds of any of the
showers impacting the taf sites seem low enough to leave them out
of the tafs. Showers and clouds should diminish around sunset once

Grb watches/warnings/advisories...


Short term.....Kurimski
long term......mpc

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