Special Weather Statement, NWS Milwaukee, WI

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
358 PM CDT Wed Jul 5 2017

.SHORT TERM...
Tonight through Thursday Night...Forecast Confidence is Medium.

Showers and thunderstorms that developed over central WI along an
outflow boundary continue to expand south and east this afternoon.
There are even some storms along the western periphery of the
outflow as well. They are weakening as the outflow gets out ahead
of the convection. We are watching a few showers pop up along the
lake breeze/outflow boundary now. The better instability is over
southwest/south central WI where there are higher dewpoints. Surface-
based CAPE 2500-3000 j/kg. This is where the storms continue to
develop. The bulk shear is very low. The environment is favorable
for pulse thunderstorms to produce gusty winds and small hail,
but very heavy rain.

We are still in an area of enhanced risk for severe storms on
Thursday. This seems reasonable given high instability, moderate
shear, and a low-level trough moving through Thu evening. Given
the projected location of the low level jet nosing into northern
WI, a probable scenario is that the better supercells would
develop up there and then develop into a more linear complex as it
expands southeast. Southern WI would have the better threat for
damaging winds and large hail due to lines of thunderstorms. This
all may change by tomorrow, but this is the current thinking.

.LONG TERM...
.Friday through Wednesday...Forecast confidence is medium to low

After the cold front moves through late Thursday night, cooler and
drier conditions will come in with a ridge of high pressure
settling in down around the Mid-Mississippi River Valley region
into the weekend. There is a hint of some weak low level moisture
return on Saturday night into Sunday which angles up into
southwest Wisconsin and could provide some focus for convection.

Beyond that going into next week, there are timing differences
between the GFS and ECMWF with the next cold front arrival with
the GFS being a quicker solution than the ECMWF which pushes it
back until mid week. Regardless, the cooler northwest flow aloft
pattern appears to hold on through next week. Just a matter of
when the next system comes in.

&&

.AVIATION(18Z TAFS)...
Scattered showers and thunderstorms into the early evening
across south central WI and potentially east central/ southeast
WI. This is due to very moist and unstable air over the area.
Pea-sized hail and gusty winds are possible, but no severe storms
are expected.

There is a chance for thunderstorms Thu early afternoon, but the
better chance is late Thu afternoon through late Thu evening just
ahead of a cold front. Some of these storms could be severe.

&&

.MARINE...
Southerly winds will continue through Thu evening. Thunderstorms
are likely Thu evening along a cold front.

Look for northerly winds behind the front on Friday. Winds and waves
are expected to remain below small craft advisory criteria.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

Tonight/Thursday Night and Aviation/Marine...Cronce
Friday through Wednesday...Halbach

Hazardous Weather Outlook
National Weather Service Milwaukee/Sullivan WI
347 PM CDT Wed Jul 5 2017

WIZ046-047-051-052-056>060-062>072-062100-
Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
347 PM CDT Wed Jul 5 2017

This Hazardous Weather Outlook is for portions of east central
Wisconsin, south central Wisconsin, and southeast Wisconsin.

.DAY ONE...Tonight

Thunderstorms are possible late this afternoon into the evening
hours. Gusty winds to 40 mph, small hail to the size of pennies
and heavy rainfall are possible with these storms.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

Severe thunderstorms are expected for late Thursday afternoon into
Thursday night. The primary threats will be damaging wind to 70
mph and large hail to the size of golf balls. A tornado or two can
not be ruled out as well.

There also is a chance of thunderstorms on Sunday night.

.SPOTTER INFORMATION STATEMENT...

Spotter reports of heavy rainfall, small hail and gusty winds are
appreciated into tonight. Spotter activation will likely be
needed Thursday afternoon and evening.

LMZ643>646-062100-
Sheboygan to Port Washington WI-
Port Washington to North Point Light WI-
North Point Light to Wind Point WI-
Wind Point WI to Winthrop Harbor IL-
347 PM CDT Wed Jul 5 2017

This Hazardous Weather Outlook is for portions of Lake Michigan.

.DAY ONE...Tonight

Thunderstorms are possible with gusty winds to 40 mph occurring
ahead of the storms.

.DAYS TWO THROUGH SEVEN...Thursday through Wednesday

Severe thunderstorms are expected for late Thursday afternoon into
Thursday night. The primary threats will be damaging wind and
large hail.

There also is a chance of thunderstorms on Sunday.

Halbach

www.weather.gov/mkx

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
445 PM CDT WED JUL 5 2017

WIZ062-067-052215-
Lafayette-Iowa-
445 PM CDT WED JUL 5 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN LAFAYETTE AND SOUTHERN
IOWA COUNTIES...

At 444 PM CDT, a strong thunderstorm was located 8 miles southeast of
Mineral Point, moving east at 10 mph.

Winds in excess of 30 mph and nickel size hail are possible with this
storm.

Locations impacted include...
Mineral Point, Darlington, Belmont, Argyle, Blanchardville, Linden,
Cobb, Lamont, Rewey, Hollandale, Platte Mounds, Yellowstone Lake St
Park, London and Leslie.

LAT...LON 4301 9043 4285 8984 4268 8984 4270 9043
TIME...MOT...LOC 2144Z 275DEG 7KT 4280 9005

MRC

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
447 PM CDT WED JUL 5 2017

WIZ065-066-071-052200-
Waukesha-Milwaukee-Racine-
447 PM CDT WED JUL 5 2017

...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL MILWAUKEE...NORTH
CENTRAL RACINE AND SOUTHEASTERN WAUKESHA COUNTIES...

At 447 PM CDT, a strong thunderstorm was located over Big Bend, or
near Muskego, moving southeast at 20 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm.

Locations impacted include...
Milwaukee, Waukesha, West Allis, New Berlin, Brookfield, Greenfield,
Muskego, Greendale, Hales Corners, Mukwonago, West Milwaukee, Wind
Lake, Big Bend, Waterford North, State Fair Park and Mitchell Park
Domes.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 4287 8836 4302 8825 4303 8793 4279 8813
TIME...MOT...LOC 2147Z 300DEG 18KT 4291 8821

HENTZ

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
457 PM CDT WED JUL 5 2017

WIZ065-066-070-071-052215-
Walworth-Waukesha-Milwaukee-Racine-
457 PM CDT WED JUL 5 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN WALWORTH...
NORTHWESTERN RACINE AND SOUTHEASTERN WAUKESHA COUNTIES...

At 457 PM CDT, a strong thunderstorm was located over Big Bend, or
near Mukwonago, moving south at 10 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm.

Locations impacted include...
New Berlin, Muskego, Mukwonago, Wind Lake, Big Bend, Waterford North,
Potter Lake, Waterford and Honey Creek.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 4291 8839 4300 8810 4282 8804 4272 8831
TIME...MOT...LOC 2157Z 343DEG 11KT 4287 8824

HENTZ

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
515 PM CDT WED JUL 5 2017

WIZ065-066-071-052245-
Waukesha-Milwaukee-Racine-
515 PM CDT WED JUL 5 2017

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN MILWAUKEE...
NORTHWESTERN RACINE AND SOUTHEASTERN WAUKESHA COUNTIES...

At 515 PM CDT, a strong thunderstorm was located over New Berlin,
moving south at 10 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm.

Locations impacted include...
Milwaukee, Waukesha, West Allis, Wauwatosa, New Berlin, Brookfield,
Greenfield, Oak Creek, Muskego, Greendale, Hales Corners, Elm Grove,
Wind Lake, Big Bend, Waterford North and Milwaukee Co Zoo.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4301 8827 4306 8804 4289 8794 4278 8824
TIME...MOT...LOC 2215Z 343DEG 10KT 4297 8813

HENTZ

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
530 PM CDT WED JUL 5 2017

WIZ071-052300-
Racine-
530 PM CDT WED JUL 5 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN RACINE COUNTY...

At 530 PM CDT, a strong thunderstorm was located over Waterford
North, or near Wind Lake. the storm is nearly stationary.

Winds in excess of 30 mph and half inch hail are possible with this
storm.

Locations impacted include...
Wind Lake, Rochester, Waterford North, Eagle Lake, Waterford and
Honey Creek.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4284 8831 4284 8814 4270 8808 4270 8831
TIME...MOT...LOC 2230Z 336DEG 4KT 4280 8824

MRC

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
557 PM CDT WED JUL 5 2017

WIZ070>072-052330-
Walworth-Racine-Kenosha-
557 PM CDT WED JUL 5 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTHERN WALWORTH...
WESTERN RACINE AND WESTERN KENOSHA COUNTIES...

At 556 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Rochester to near Lake Geneva to
Walworth. Movement was south at 10 mph.

Winds in excess of 30 mph are possible with these storms.

Locations impacted include...
Elkhorn, Delavan, Lake Geneva, Twin Lakes, Union Grove, Paddock Lake,
Williams Bay, Camp Lake, Rochester, Genoa City, Walworth, Silver
Lake, Richmond, Fontana-On-Geneva Lake, Sharon, Darien, Powers Lake,
Browns Lake, Como and Pell Lake.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4260 8872 4268 8837 4282 8812 4265 8799
      4249 8820 4249 8873
TIME...MOT...LOC 2256Z 352DEG 10KT 4276 8817 4262 8837 4255 8862

HENTZ