Severe Thunderstorm Warning 38, NWS Milwaukee, WI

794 
WWUS53 KMKX 171932
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
232 PM CDT WED MAY 17 2017

WIC021-025-111-171945-
/O.CON.KMKX.SV.W.0038.000000T0000Z-170517T1945Z/
Columbia WI-Dane WI-Sauk WI-
232 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM CDT
FOR SOUTHWESTERN COLUMBIA...NORTHWESTERN DANE AND EASTERN SAUK
COUNTIES...

At 232 PM CDT, a severe thunderstorm was located over Prairie Du Sac,
moving northeast at 50 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

Locations impacted include...
Baraboo, Prairie Du Sac, Sauk City, Lake Wisconsin, West Baraboo,
Merrimac, Harmony Grove, Interstate 90/94 Interchange, Okee and
Devils Lake St Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4360 8972 4345 8939 4322 8977 4320 8982
      4321 8984 4321 8985 4328 8988
TIME...MOT...LOC 1932Z 214DEG 36KT 4330 8977 

HAIL...1.00IN
WIND...<50MPH
 
$$

SPM

749 
WWUS53 KMKX 171940
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
240 PM CDT WED MAY 17 2017

WIC025-171946-
/O.CAN.KMKX.SV.W.0038.000000T0000Z-170517T1945Z/
Dane WI-
240 PM CDT WED MAY 17 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN DANE COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4360 8972 4345 8939 4327 8977 4326 8982
      4329 8985
TIME...MOT...LOC 1936Z 214DEG 36KT 4334 8974 

$$

WIC021-111-171945-
/O.CON.KMKX.SV.W.0038.000000T0000Z-170517T1945Z/
Columbia WI-Sauk WI-
240 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM CDT
FOR SOUTHWESTERN COLUMBIA AND EASTERN SAUK COUNTIES...

At 236 PM CDT, a severe thunderstorm was located near Prairie Du Sac,
moving northeast at 40 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

Locations impacted include...
Baraboo, Prairie Du Sac, Lake Wisconsin, West Baraboo, Merrimac,
Interstate 90/94 Interchange and Devils Lake St Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4360 8972 4345 8939 4327 8977 4326 8982
      4329 8985
TIME...MOT...LOC 1936Z 214DEG 36KT 4334 8974 

HAIL...1.00IN
WIND...<50MPH
 
$$

SPM

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1249 PM CDT Wed May 17 2017

.UPDATE...

It is quiet right now, but that should change over the next couple
hours as more storms develop across the area. No changes to the
severe potential for the afternoon and evening hours.

&&

.AVIATION(18Z TAFS)...

A couple more rounds of storms are expected this afternoon and
evening ahead of approaching low pressure. Some of the storms may
be severe. A few showers may linger past midnight, with another
round of showers possible tomorrow as the cold front slides
through. The showers tomorrow will be on the light side.

Low level wind shear looks possible again tonight...from around
mid/late evening through late tonight.

Outside of lower visibilities in thunderstorms, mainly VFR
conditions are expected into tonight. Will likely see lower
ceilings tomorrow near and behind the advancing cold front.

&&

.PREV DISCUSSION... (Issued 1001 AM CDT Wed May 17 2017)

UPDATE...

The first round of showers is currently moving thought the
western forecast area, with a little embedded thunder. After this
round exits by late morning, will keep an eye on upstream
development for the afternoon hours. Multiple rounds of storms are
still expected this afternoon into the evening. Should be enough
time after this first round of showers/storms exit for
temperatures and instability to recover. Wind fields still look
pretty strong for the afternoon and evening hours. SPC expanded
the Slight Risk for severe storms all the way to Lake Michigan
with the 8 am update, leaving the Enhanced Risk area in the west.
This looks reasonable given the environment and meso model output
for the afternoon/evening.

MARINE...

Southerly winds will remain gusty through Thursday, veering to the
southwest by Thursday morning. With little to no onshore
component to the winds, waves should generally stay in the 3 to 5
foot range through Thursday afternoon.

After a brief break, could see winds/waves pick back up Thursday
night into Friday.

PREV DISCUSSION... (Issued 741 AM CDT Wed May 17 2017)

UPDATE...

HRRR still shows several bands of showers and thunderstorms to
rotate through from southwest to northeast starting late morning
southwest of Madison, continuing into early evening.

Severe thunderstorms still expected this afternoon and early
evening. Tornado threat best south central Wisconsin, with a
lesser threat southeast. several bands of showers and
thunderstorms to move through starting late morning southwest of
Madison.

AVIATION(12Z TAFS)...

Expect several bands of showers and thunderstorms to move through
starting late morning southwest of Madison. MVFR/IFR conditions
in the showers/thunderstorms. Otherwise VFR. Then MVFR cigs spread
in from the northwest late tonight/Thursday.

Gusty south winds by afternoon. Wind shear again tonight.

PREV DISCUSSION... (Issued 241 AM CDT Wed May 17 2017)

DISCUSSION...

Today and Tonight...Forecast Confidence is Medium...

Focus will be on the potential for a round of severe storms
including the potential for tornadoes. In our area, the tornado
risk will be greatest across southwest and south central Wisconsin
this afternoon and early evening.

Low pressure will exit eastern nebraska this morning to far
southeast Minnesota just before midnight., then across central
and northeast Wisconsin during the early morning hours Thursday. A
warm and moist airmass will remain in place across southern
Wisconsin during this period with zero to 1 km CAPE values around
1200 Joules/kg.

In addition, the low level 850 mb jet of 50 knots associated with
the low will nose into the area from the south during the late
afternoon. meanwhile the upper levels are diffluent into the
afternoon as the upper shortwave lifts northeast and closes off.
This should lead to several rounds of storms moving southwest to
northeast from late afternoon into the evening hours. SPC has
upgraded most of south central Wisconsin into an enhanced risk
with a slight risk over most of the rest of the area.  This
certainly seems reasonable given the instability and strong wind
sheer.

Temperatures will likely be warmest in the east where there
should be less clouds, and somewhat warmer temps aloft. Less
certainty in the west given the cloud/precipitation potential in
the morning and then redevelopment in the afternoon. It won't take
much sunshine though to push temps up to 80 even with the clouds.

By tonight mid level drying occurs late tonight as the mid level
low lifts toward the U.P. of Michigan.

THURSDAY - Confidence...Medium
Mid level trough lifts off to the northeast of WI. A surface low
will shift northeast with a trailing cold front coming through
from during the afternoon. 925 temps will be collapsing with time
as winds shift northerly and bring in a chillier airmass. Both the
NAM and GFS Bufkit soundings show an inversion around 700
millibars which is limiting any instability so appears that precip
would be mainly shra with little thunder potential.

FRIDAY - Confidence...Medium
Cool surface high will be dominant. 925 temps well down in the
single digits celsius. There is a mid level wave that swings
through however Bufkit soundings show a dry layer of considerable
depth that most likely will not be overcome despite the passage of
this feature in the mid/upper levels. So will go with the
consensus of the NAM/GFS MOS and steer clear of the GEM solution
at this time.

FRIDAY NIGHT AND SATURDAY - Confidence...Medium
Pronounced mid level trough in the Plains will eject energy
northeast and this leads to cyclogenesis which then allows for LLJ
to advect moisture northward into the cwa, so expect forcing and
moisture parameters to become favorable for precip this period.
Bufkit shows a fairly substantial low level inversion with some
elevated instability, so will retain the mention of thunder for
Saturday. Nice bounce back in the 925 temps but with the
clouds/precip and lack of deep mixing not likely to realize the
full potential of this modified airmass.

SUNDAY - Confidence...Medium
Low pressure and associated cold front shifts east. best rain
chances look to be in the morning. The GEM is again an outlier
with a very strong low moving northeast into the area late Sunday
and Sunday night, but will follow consensus of the ECMWF and GFS
with a progressive front.

MONDAY - Confidence...Medium
The GFS and ECMWF show the mid level flow becoming more zonal
with little in the way of disturbances in the flow meanwhile the
GEM remains an outlier with strong cyclonic influence of the wave
lifting northeast. However there is a surface/850 trough that may
generate a few showers into Monday night.

TUESDAY - Confidence...Medium
The mid level flow continues to show the potential for more
shortwave activity so no reason to deviate from the Superblend
pops. there is a low level thermal trough in place so 925 temps
and a northerly wind will keep it cool.

AVIATION(06Z TAFS)...Wind shear tonight and again Wednesday night.
Gusty southerly winds Wed afternoon. There is a lot of uncertainty
regarding timing of showers and thunderstorms on Wednesday. Keep
up with the latest TAFs and forecasts.

MARINE...South winds will increase this afternoon, remaining gusty
through mid-week as low pressure exits the central plains, moves
across central Wisconsin tonight, and over lake Huron Thursday. A
Small Craft Advisory is in effect through Thursday afternoon.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory until 4 PM CDT Thursday for LMZ643>646.

&&

Update...DDV
Today/Tonight and Aviation/Marine...Hentz
Thursday THROUGH Tuesday...Collar

Hazardous Weather Outlook
National Weather Service Milwaukee/Sullivan WI
340 AM CDT Wed May 17 2017

WIZ046-047-051-052-056>060-062>072-180845-
Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
340 AM CDT Wed May 17 2017

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

.DAY ONE...Today and Tonight

Thunderstorms are likely across south central Wisconsin with a
chance of thunderstorms southeast today into this evening. The
period of greatest concern for severe thunderstorms is late
afternoon into the early evening especially across south central
Wisconsin where there is a greater risk of a few tornadoes, large
hail and damaging winds.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

There is a chance of thunderstorms again on Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

LMZ643>646-180845-
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-
340 AM CDT Wed May 17 2017

This Hazardous Weather Outlook is for portions of Lake Michigan.

.DAY ONE...Today and Tonight

A small craft advisory is in effect for breezy southerly winds.

There is a chance of thunderstorms this afternoon and evening.
There is a marginal risk of severe thunderstorms.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

A small craft advisory is in effect through Thursday afternoon
for breezy southerly winds.

There is a chance of thunderstorms again on Saturday.

Collar
www.weather.gov/mkx

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
216 PM CDT WED MAY 17 2017

WIZ056-057-062-063-171945-
Columbia-Iowa-Sauk-Dane-
216 PM CDT WED MAY 17 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN IOWA...SOUTHWESTERN
COLUMBIA...NORTHWESTERN DANE AND EASTERN SAUK COUNTIES...

At 215 PM CDT, a strong thunderstorm was located near Mazomanie, or
11 miles southwest of Sauk City, moving northeast at 40 mph.

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

Locations impacted include...
Baraboo, Prairie Du Sac, Sauk City, Lake Wisconsin, Lodi, Mazomanie,
West Baraboo, Black Earth, Arena, Merrimac, Harmony Grove, Okee and
Devils Lake St Park.

LAT...LON 4305 8986 4315 9006 4357 8974 4341 8943
TIME...MOT...LOC 1915Z 214DEG 37KT 4317 8990

SPM