Special Weather Statement, NWS Green Bay, WI

Area Forecast Discussion
National Weather Service Green Bay WI
1130 AM CDT TUE SEP 6 2016

Updated aviation portion for 18Z TAF issuance

.UPDATE...
Issued at 447 AM CDT Tue Sep 6 2016

Have coordinated with MQT and MKX, and decided to expand the Flood
Watch farther east to the lakeshore. Rainfall totals are just as
high there, and WPC has nearly the entire forecast area in the day
1 slight risk for excessive rainfall.
&&

.SHORT TERM...Today...Tonight...and Wednesday
Issued at 357 AM CDT Tue Sep 6 2016

Thunderstorms were ongoing in a region of enhanced moisture
convergence ahead of a cold front, which extended from western
Lake Superior swwd to far northwest WI and southwest MN. Storms
were rapidly increasing over far north central WI. A few of these
storms were strong, due to an axis of moderate instability (MUCAPE
1000-1500 j/kg) and deep layer shear of 30-40 kts. The storms were
also producing heavy rainfall, as PWATs were increasing to 1.75 to
2 inches ahead of the front.

The cold front will continue to be the focus of convective
development through Wednesday, with the highest pops focused
over north central WI this morning and early afternoon, shifting
into central and northeast WI later this afternoon and tonight,
then the Fox River Valley and Lakeshore region on Wednesday. With
PWATs around 2 inches continuing through the event, the main focus
will be on heavy rainfall and potential flooding (see Hydrology
section below). However, severe thunderstorms will also be a
concern, particularly this afternoon and early evening, when
SBCAPE is forecast to reach 1500-2000 j/kg, along with deep layer
shear of 30-45 kts. One negative factor will be abundant cloud
cover from morning and upstream convection, so confidence on the
details is low. SPC has most of GRB CWA in a slight risk, which
seems reasonable. Will also need to see exactly where the front
resides Wednesday afternoon, but instability/shear parameters are
at least marginal for severe thunderstorms in our far southern
counties.

Used a blend of the better performing guidance sets for
temperatures. Today will be very warm and humid over all but the
far northwest, but some cooling will be seen on Wednesday,
especially over our northwest counties, which will be stuck in
low cloud cover on the cool side of the front.

.LONG TERM...Wednesday Night Through Monday
Issued at 357 AM CDT Tue Sep 6 2016

Forecast concerns revolve around heavy rain potential on Wednesday
night, followed by the next precip chance arriving on Friday and
Friday night.  Looking at model solutions tonight, both the nam and
gfs appear too strong with the surface low that crosses the region
Wednesday night.  But given the moisture profiles, prefer something
between these stronger solutions and the ecmwf.  Will continue to
side with the ecmwf for the second system arriving late this week.

Wednesday night through Thursday night...The potential for heavy
rainfall will continue into Wednesday night. Ensemble means indicate
that pwats and integrated wv transport will target east-central WI
early in the evening before shifting southward.  Elevated instability
is pretty meager, but forcing from a shortwave and mid-level
convergence could have enough to overcome that negative.  Will
continue to advertise heavy rainfall in this area, possibly an
additional 1-2 inches in the evening.  Once any heavy rain departs,
lighter shower activity could continue, especially over northern WI,
into Thursday morning before ending.  Then weak high pressure will
bring clearing skies Thursday afternoon and evening for a relatively
short period. Clouds will then increase late ahead of the next
system.

Rest of the forecast... The next shortwave will be sending another
low pressure system over the Great Lakes region on Friday and Friday
night.  This time it looks like the deep moisture plume will remain
south of the region, but the system should still bring some showers
to the region, highest threat over east-central WI.  Cooler and
drier air will move in behind the system for Saturday and Sunday.
Another surge of warmer air will quickly follow for early next week
ahead of the next front.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1122 AM CDT Tue Sep 6 2016

Poor flying conditions will continue tonight and Wednesday due to
showers and storms in the area, and the possibility of low clouds
and fog. Several rounds of showers and thunderstorms will move
across the area through Wednesday afternoon. A few of the storms
could be strong or severe this afternoon with strong winds and
hail south of a Marinette to Wausau line. Between the rounds of
storms tonight into Wednesday morning, low clouds and some fog
should develop, especially across northern Wisconsin.

&&

.HYDROLOGY...
Issued at 357 AM CDT Tue Sep 6 2016

Locally heavy rain expected at times today through Wednesday
night. Most locations should see between 2 and 3 inches of rain
with locally higher amounts possible. WPC has most of our forecast
area in a slight risk for exceeding flash flood guidance for today
and tonight.

Have decided to expand the Flood Watch farther east, as expected
rainfall amounts are just as high in eastern WI. In addition to
the potential for river flooding, have mentioned the potential for
urban flooding in the Flood Watch text.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late Wednesday night FOR WIZ010-011-013-
018>022-030-031-035>040-045-048>050-073-074.
&&

UPDATE.........Kieckbusch
SHORT TERM.....Kieckbusch
LONG TERM......MPC
AVIATION.......Eckberg
HYDROLOGY......Kieckbusch

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREEN BAY WI
1114 AM CDT TUE SEP 6 2016

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-071615-
VILAS-ONEIDA-FOREST-FLORENCE-NORTHERN MARINETTE COUNTY-LINCOLN-
LANGLADE-MENOMINEE-NORTHERN OCONTO COUNTY-DOOR-MARATHON-SHAWANO-
WOOD-PORTAGE-WAUPACA-OUTAGAMIE-BROWN-KEWAUNEE-WAUSHARA-WINNEBAGO-
CALUMET-MANITOWOC-SOUTHERN MARINETTE COUNTY-
SOUTHERN OCONTO COUNTY-
1114 AM CDT TUE SEP 6 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL CONTINUE AT TIMES THROUGH LATE TONIGHT. THERE
IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND THIS
EVENING GENERALLY SOUTH OF A WAUSAU TO MARINETTE LINE. A FEW OF
THE STORMS COULD BE SEVERE WITH DAMAGING WINDS AND HAIL.

HEAVY RAINFALL IS LIKELY AT TIMES THROUGH LATE TONIGHT. THE
STORMS WILL BE CAPABLE OF PRODUCING RAINFALL RATES OF 1 TO
2 INCHES PER HOUR, STREET FLOODING AND PONDING OF WATER
ON AREA ROADWAYS. DITCHES, CREEKS AND RIVERS WILL BE ON THE
RISE ALONG WITH FAST CURRENTS. RESIDENTS SHOULD MONITOR RIVER
LEVELS AND FORECASTS FOR THE LATEST INFORMATION ON THE HEAVY
RAIN EVENT. A FLOOD WATCH REMAINS IN EFFECT FOR MUCH OF THE
AREA THROUGH WEDNESDAY NIGHT FOR SEVERAL MORE ROUNDS OF
THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

PERIODS OF SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH WEDNESDAY
NIGHT. TOTAL RAINFALL AMOUNTS OF 2 TO 3 INCHES, WITH LOCALIZED
HIGHER AMOUNTS, ARE EXPECTED ACROSS MUCH OF THE AREA FROM TODAY
THROUGH EARLY THURSDAY MORNING. THE HEAVY RAIN MAY RESULT IN URBAN
STREET FLOODING AND RAPID RISES ON AREA RIVERS AND CREEKS.
RESIDENTS LIVING ALONG RIVERS AND CREEKS SHOULD MONITOR WATER
LEVELS OVER THE NEXT FEW DAYS.

A CHANCE OF THUNDERSTORMS WILL RETURN LATE IN THE WORK WEEK. IT IS
TOO EARLY TO DETERMINE IF THERE IS A CHANCE OF SEVERE WEATHER.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.
SPOTTERS ARE ALSO URGED TO RELAY ANY REPORTS OF FLOODING OR HEAVY
RAINFALL IN EXCESS OF AN INCH.

LMZ521-522-541>543-071615-
THE BAY OF GREEN BAY SOUTH OF A LINE FROM CEDAR RIVER MI TO ROCK
ISLAND PASSAGE-LAKE MICHIGAN FROM WASHINGTON ISLAND TO SHEBOYGAN-
1114 AM CDT TUE SEP 6 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST LAKE
MICHIGAN AND THE WATERS OF GREEN BAY.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS ARE POSSIBLE TODAY AND TONIGHT.  SOME OF THE STORMS
THIS AFTERNOON AND EVENING COULD BECOME STRONG OR SEVERE, WITH
STRONG WINDS, TORRENTIAL RAINFALL AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

PERIODS OF SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
WEDNESDAY NIGHT, AND POSE A HAZARD TO MARINERS.

ADDITIONAL STORMS ARE EXPECTED LATER THIS WEEK...RESULTING IN
HAZARDOUS CONDITIONS FOR BOATERS ON THE LAKE AND BAY.

ECKBERG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREEN BAY WI
913 AM CDT TUE SEP 6 2016

WIZ010-018-019-061445-
LANGLADE-LINCOLN-ONEIDA-
913 AM CDT TUE SEP 6 2016

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN
LANGLADE...SOUTHERN ONEIDA AND LINCOLN COUNTIES...

AT 912 AM CDT...RADAR INDICATED STRONG THUNDERSTORMS WERE LOCATED
ALONG A LINE EXTENDING FROM 5 MILES EAST OF TRIPOLI TO NEAR COUNCIL
GROUNDS STATE PARK. MOVEMENT WAS EAST AT 45 MPH.

WINDS IN EXCESS OF 30 MPH ARE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
RHINELANDER...MERRILL...TOMAHAWK...WOODBORO...PARRISH...PEARSON...
COUNCIL GROUNDS STATE PARK...BRADLEY...ELCHO AND NEVA.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THESE STORMS...AND MAY
CAUSE LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

LAT...LON 4561 8998 4578 8915 4552 8904 4547 8905
      4546 8902 4519 8891 4517 8980
TIME...MOT...LOC 1412Z 260DEG 49KT 4556 8988 4525 8975

RDM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
1014 AM CDT TUE SEP 06 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1012 AM     HEAVY RAIN       1 S LAKE TOMAHAWK       45.80N 89.59W
09/06/2016  E2.24 INCH       ONEIDA             WI   TRAINED SPOTTER

            RECEIVED BETWEEN 2.00-2.24 INCHES OF RAIN IN 4 HOURS.

&&

AK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
1048 AM CDT TUE SEP 06 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1012 AM     HEAVY RAIN       THREE LAKES             45.79N 89.16W
09/06/2016  M1.95 INCH       ONEIDA             WI   TRAINED SPOTTER

            1.95 INCHES OF RAIN FELL IN A 5-HOUR PERIOD THIS MORNING.
            LOCALIZED STREET FLOODING IN THREE LAKES.

&&

AK

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREEN BAY WI
302 PM CDT TUE SEP 6 2016

WIZ031-037>039-062100-
WAUPACA WI-BROWN WI-SHAWANO WI-OUTAGAMIE WI-
302 PM CDT TUE SEP 6 2016

...STRONG THUNDERSTORMS MOVING ACROSS EAST-CENTRAL WISCONSIN...

AT 300 PM CDT...DOPPLER RADAR WAS TRACKING A SMALL LINE OF STRONG
THUNDERSTORMS FROM NEAR NAVARINO WILDLIFE AREA TO 7 MILES NORTHWEST
OF NEW LONDON TO NEAR WAUPACA. MOVEMENT WAS EAST AT 30 MPH.

HALF INCH HAIL, WINDS IN EXCESS OF 30 MPH AND TORRENTIAL
DOWNPOURS WILL BE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
GREEN BAY...APPLETON...WAUPACA...NEW LONDON...BLACK CREEK...ONEIDA...
HOWARD...ASHWAUBENON...SUAMICO AND GREENVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THESE STORMS...AND MAY
LEAD TO LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH
FLOODED ROADWAYS.

&&

LAT...LON 4428 8911 4447 8885 4465 8850 4465 8793
      4463 8793 4465 8788 4465 8784 4444 8819
      4425 8848
TIME...MOT...LOC 2000Z 274DEG 26KT 4462 8855 4448 8882 4437 8898

AK