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Area forecast discussion 
National Weather Service Green Bay WI
600 am CDT Sat may 23 2015

Updated aviation portion for 12z taf issuance

Short Sunday
issued at 304 am CDT Sat may 23 2015

Ridging will keep the weather dry and warm today and tonight as a
low pressure system develops across the Central Plains. While this
low will stream in high level clouds across Wisconsin today and
tonight...nwp models continue to indicate dry conditions during
the first part of the forecast with a dry stable atmosphere in
place. Previous model runs indicated this system would bring the
chance for rain across the southern portion of the County Warning Area late
tonight...however the aforementioned high has delayed these
chances as the low moves in a bit slower than previous runs
indicated. Given the new model guidance have removed all probability of precipitation
across the area during the overnight hours.

After a cool start this morning...highs today should rebound
nicely into the lower to middle 70s away from the lake as warm
air advection continues to bring warmer temperatures into the
state. Near the lake highs are expected to be in the middle to
upper 60s. While previous forecasts were concerned with cloud
cover keeping highs tempered this afternoon...the slower
progression of this low pressure system should keep the thicker
clouds at Bay...allowing daytime highs to reach the aforementioned
levels indicated by MOS guidance. The GFS continues to generate
light quantitative precipitation forecast across Wisconsin during the afternoon hours. However the
model soundings do not bear this out given the abundant dry air in
place across the area. Therefore will continue with a dry forecast

Thicker clouds should advect in during the overnight hours as the
low develops over the Central Plains. The clouds...when combined
with continued warm air advection...will keep temperatures mild
when compared to the last few nights. Overnight lows are expected
to drop to around 50 across the north...with low to middle 50s across
the southern County Warning Area.

The slower than expected arrival of the rain will continue into
Sunday as the low slowly organizes over the plains and pumps moist
air in from the Gulf as dew points soar into the 50s across the
County Warning Area during the afternoon hours. The best chances for rain are not
expected until the afternoon when better moisture arrives and a
middle level shortwave tracks through the western Great Lakes
coincident with a surge of low level Theta-E advection. Given the
delayed arrival of these elements will lower probability of precipitation Sunday morning
and focus on the afternoon hours for the best rain chances. The
later rain arrival should also mean high temperatures will be a
bit higher than previously forecast which is reflected in the new
MOS guidance numbers.


Long term...Sunday night through Friday
issued at 304 am CDT Sat may 23 2015

There are plenty of chances for rain during the upcoming week
with southwest upper level flow early next week transitioning to
a more zonal pattern by the middle of the week. Difficult to pick
out a period of dry weather...but the 00z GFS and 00z European model (ecmwf)
brought a dry slot across the southeast 2/3rds of Wisconsin on
Monday afternoon. Have attempted to depict this in forecast grids
but still have at least a slight chance for thunder. Other periods
of dry weather are likely but timing remains uncertain. Think
there will be some dry weather around the middle of the week
before rain chances return to the area...but the more zonal upper
level flow will make timing a huge question mark at this point.

Expect above normal temperatures early in the week...cooling to
near normal during the latter half of the week.

Aviation...for 12z taf issuance
issued at 600 am CDT Sat may 23 2015

VFR conditions are anticipated through the taf
Canadian high pressure gradually shifts east. High clouds will
increase over c/ec WI today...with thickening middle-level clouds
arriving this evening. Light winds are expected tonight...with
S-SW winds increasing to around 10 kts this afternoon.

Grb watches/warnings/advisories...


Short term.....Kurimski

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