Severe Thunderstorm Warning 74, NWS Milwaukee, WI

283 
WWUS53 KMKX 252042
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
342 PM CDT TUE SEP 25 2018

WIC021-027-039-047-252115-
/O.CON.KMKX.SV.W.0074.000000T0000Z-180925T2115Z/
Green Lake WI-Fond du Lac WI-Columbia WI-Dodge WI-
342 PM CDT TUE SEP 25 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM CDT
FOR GREEN LAKE...SOUTHWESTERN FOND DU LAC...NORTHEASTERN COLUMBIA AND
NORTHWESTERN DODGE COUNTIES...

At 342 PM CDT, severe thunderstorms were located along a line
extending from 6 miles west of Markesan to near Randolph, moving
northeast at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Waupun, Ripon, Randolph, Markesan, Green Lake, Brandon, Cambria, Fox
Lake, Alto, Manchester, Fairwater, Friesland, Kingston, Marquette and
Astico.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4390 8888 4390 8885 4360 8865 4350 8910
      4363 8918 4365 8920 4373 8919 4377 8917
      4380 8917 4392 8889
TIME...MOT...LOC 2042Z 246DEG 30KT 4371 8912 4354 8900 

HAIL...<.75IN
WIND...60MPH
 
$$

GEHRING

115 
WWUS53 KMKX 252048
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
348 PM CDT TUE SEP 25 2018

WIC021-027-039-047-252058-
/O.CAN.KMKX.SV.W.0074.000000T0000Z-180925T2115Z/
Green Lake WI-Fond du Lac WI-Columbia WI-Dodge WI-
348 PM CDT TUE SEP 25 2018

...THE SEVERE THUNDERSTORM WARNING FOR GREEN LAKE...SOUTHWESTERN FOND
DU LAC...NORTHEASTERN COLUMBIA AND NORTHWESTERN DODGE COUNTIES IS
CANCELLED...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southeastern Wisconsin.

LAT...LON 4390 8888 4390 8885 4360 8865 4350 8910
      4363 8918 4365 8920 4373 8919 4377 8917
      4380 8917 4392 8889
TIME...MOT...LOC 2047Z 239DEG 29KT 4373 8907 4356 8895 

$$

GEHRING

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
129 PM CDT Tue Sep 25 2018

.UPDATE...

We are growing more unstable early this afternoon as most of the
low clouds scattered out. SPC mesoanalysis shows surface-based
CAPE is up to 1500 j/kg over our southeast now. Thunderstorms are
expanding along the leading edge of the front over eastern Iowa
now. In southeast WI, there is stratus out ahead of the line, so
that area is not as unstable. The cirrus blow-off from upstream
storms may also cause a little drop in the instability.

Shear continues to be favorable for strong storms. Line segments
with damaging winds are the main threat, although we have the
right conditions for mesovortex (tornado) development within any
QLCS (quasi-linear convective system) line segments. We will have
strong 0-3 km shear of 30 to 40 kt in a favorable direction to
align perpendicular to any bowing line segments.

Severe Thunderstorm Watch #388 until 2Z/10pm will be issued soon
for portions of the MKX forecast area.

&&

.AVIATION(18Z TAFS)...

Low clouds scattered out and cloud bases are mostly VFR across
south central and southeast WI. Expect a period of MVFR with
intermittent IFR with a line of thunderstorms that crosses
southern Wisconsin along a cold front this afternoon and evening.
Damaging winds and possibly a tornado are possible with these
storms.

Gusty northwest winds are expected in the wake of the front
overnight. Low clouds will probably clear out late tonight and
then re-develop by mid Wednesday morning.

&&

.PREV DISCUSSION... (Issued 1112 AM CDT Tue Sep 25 2018)

UPDATE...

Low pressure will cross the Upper Midwest and Great Lakes region
this afternoon into the evening. A surface front currently extends
from central Iowa to northeast Wisconsin this morning. An
additional surge of moisture will slide northeast along the front
into south central WI around mid day, and this is coincident with
mid level vorticity advection. That surge of moisture features
precipitable water values of around 1.5 inches, so any storms we
get this afternoon can have brief heavy downpours.

We are closely watching our cloud cover today to help determine
how much instability we will get out ahead of the front crossing
southern Wisconsin this afternoon. The morning low clouds are
finally starting to break up which will help CAPE build to
700-1200 j/kg by early afternoon.

Regardless of instability, the shear will be strong over southern
WI this afternoon and having strong shear can overcome the lack
of instability in terms of getting severe storms. Bulk shear will
be in the 30 to 40 kt range. Damaging wind is the main threat in
any bowing line segments that could develop. However, we have the
right conditions for mesovortex (tornado) development within any
QLCS (quasi-linear convective system) line segments. We will have
strong 0-3 km shear of 30 to 40 kt in a favorable direction to
align perpendicular to any bowing line segments.

The latest few rounds of the HRRR model show heavier
thunderstorms arriving in the Dells/Mineral point area between 3
and 4 pm, Madison between 4 and 5 pm, and then weakening storms as
the line tracks farther east, reaching the lakeshore between 6 and
7 pm.

MARINE...

A cold front will slide through Wisconsin and Lake Michigan this
afternoon and evening. Gusty northwest winds are expected just
behind the front tonight. A few gale force gusts to 35 knots are
possible between midnight and 3 am over the open waters. A small
craft advisory is in effect for the nearshore waters for tonight.

Gusty southerly winds will develop ahead of a cold front over the
north half of Lake Michigan Thursday afternoon. Gale force winds
are expected over the north half of the lake, so a gale watch will
be needed.

PREV DISCUSSION... (Issued 545 AM CDT Tue Sep 25 2018)

UPDATE...

Areas of fog this morning has formed in areas of clear skies with
our higher dewpoints in place. This should burn off quickly with
sunrise and increasing surface winds. No changes to the impending
frontal passage later today and the accompanying showers and
storms. It does look like we'll get into some sunshine and
increasing destabilization for those storms this afternoon.

AVIATION(12Z TAFS)...

We're seeing quite a bit of low stratus and some fog around the
area this morning. It's a mix of MVFR and IFR CIGS/VSBYS. It
should mix out quickly after sunrise as surface winds begin to
increase. Then look for VFR conditions until a cold frontal
passage later this afternoon and evening. That front will push
into the area this afternoon, reaching KMSN around 22-23z today
and KMKE/KUES/KENW about 01-02z Wed. Expect a quick wind shift
from southwest to northwest with the frontal passage. In addition,
a line of showers and thunderstorms will accompany the front,
some of those storms could be strong to severe. A period of
MVFR/IFR CIGS will arrive in the cold air advection regime post
frontal tonight, clearing out by 10-12z Wednesday.

PREV DISCUSSION... (Issued 257 AM CDT Tue Sep 25 2018)

SHORT TERM...

Today and Tonight...Forecast confidence is medium.

A surface cold front stretches from the western basin of Lake
Superior, southwest to the Des Moines area early this morning. The
front is mostly quiet, with a few showers along it over northern
Wisconsin. It will drift slowly east southeast today. A strong mid
level trough and sharp h8 cold front will catch up to the surface
front this afternoon, likely resulting in a line of convection
developing west of Madison by early to mid afternoon, tracking
quickly east into the early evening.

We are outlooked with a slight risk of severe over far southern
Wisconsin, with the main threat being damaging wind. The main
uncertainty with storm strength will be the amount of
destabilization that occurs ahead of the front...and cloud cover
will dictate that. There is an axis of dry air ahead of the front
that looks like it will help to bring that clearing and
potentially raise MLCAPE into the 1000-1500J/KG range. Deep layer
shear either way will be 30-40kts. An axis of higher moisture will
sneak up into the area along and just ahead of the front with PW
values reaching 1.5in. So quick heavy rain is expected in some
spots.

The main line of storms should reach Madison by around 5-6 pm and
Milwaukee about 7-8 pm. Much cooler and drier air will push into
the area in the wake of the front tonight.

LONG TERM...

Wednesday and Thursday...Forecast confidence is high:

It will be much cooler behind the departed cold front Wednesday,
with dry weather expected under high pressure. Highs will only top
out in the low 60s.

Another low and cold front will move through Thursday into
Thursday night. Most of the moisture and lift will be to the
north, so best chance for any showers will be north of Madison and
Milwaukee. Temperatures will be closer to normal, though breezy
winds and cloudy skies will keep it feeling cool.

Friday through Monday...Forecast confidence is medium:

Models are suggesting an active pattern will setup for the weekend
into early next week. It likely won't rain every day during this
period, though ended up with precip chances every day due to the
timing/placement differences among models.

Most models keep southern Wisconsin on the cool side of the
systems Friday through the weekend, with below normal temperatures
likely. This will also cut down on any thunder chances. May see
temps warm up back toward normal early next week, with some
instability also returning to southern Wisconsin.

AVIATION(09Z TAFS)...

Mainly VFR CIGS are expected through the morning and into the
afternoon. Some fog will bring a mix of MVFR and IFR VSBYS until
shortly after sunrise. A strong cold front will push into the area
this afternoon, reaching KMSN around 23z today and KMKE/KUES/KENW
about 01-02z Wed. Expect a quick wind shift from southwest to
northwest with the frontal passage. In addition, a line of showers
and thunderstorms will accompany the front, some of those storms
could be strong to severe. A period of MVFR/IFR CIGS will arrive
in the cold air advection regime post frontal tonight, clearing
out by 10-12z Wednesday.

MARINE...

A trough of low pressure and associated cold front will approach
the western Great Lakes today. Low pressure will strengthen over
northern Lake Michigan by this evening, heading northeast by
Wednesday morning. Look for southerly winds ahead of the front
today, shifting to the northwest this evening and becoming quite
brisk overnight. We could see a few gale gusts to 35 knots between
about midnight and 6 am Wednesday in the open waters. High
pressure will then slide south of the Great Lakes Wednesday
bringing lighter westerly winds. Expect winds to back to the
southwest as the high pushes east and low pressure moves north of
Lake Superior. Those southwest winds could reach gale force levels
over the northern portion of the lake Thursday afternoon.

For the nearshore waters, will hoist a small craft advisory from
00z to 15z Wednesday due to the brisk northwest winds in the wake
of the passing cold front.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory from 7 PM this evening to 10 AM CDT
     Wednesday for LMZ643>646.

&&

Update...Cronce
Today/Tonight and Aviation/Marine...Davis
Wednesday THROUGH Monday...DDV

Hazardous Weather Outlook
National Weather Service Milwaukee/Sullivan WI
231 PM CDT Tue Sep 25 2018

WIZ046-047-051-052-056>060-062>072-261100-
Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
231 PM CDT Tue Sep 25 2018

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

.DAY ONE...Tonight

Thunderstorms are expected through early evening ahead of and
along a cold front. A Severe Thunderstorm Watch is in effect for
areas south of Port Washington and Madison. Damaging wind is the
primary threat. A tornado is possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is needed for the Watch area through early
evening.

LMZ643>646-261100-
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-
231 PM CDT Tue Sep 25 2018

This Hazardous Weather Outlook is for portions of Lake Michigan.

.DAY ONE...Tonight

Thunderstorms are expected toward evening. A Severe Thunderstorm
Watch is in effect for areas south of Port Washington with
damaging straight line winds the main threat.

A small craft advisory is in effect for tonight through Wednesday
morning for strong northwest winds developing in the wake of a
cold front.

.DAYS TWO THROUGH SEVEN...Wednesday through Tuesday

Another Small Craft Advisory may be needed on Thursday for gusty
southwest winds.

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-261100-
Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to
mid-line of lake.-
Lake Michigan from Seul Choix Point to Rock Island Passage 5NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and North of a line from Charlevoix MI to South
Fox Island 5NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to
mid lake-
Lake Michigan from Point Betsie to Manistee MI 5NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM
offshore to mid lake-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5NM offshore to Mid
Lake-
Lake Michigan from Sheboygan to Port Washington WI 5NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor to Michigan City in 5NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5NM offshore to Mid
lake-
Lake Michigan from St Joseph to South Haven MI 5NM offshore to
Mid Lake-
231 PM CDT Tue Sep 25 2018

This Hazardous Weather Outlook is for the open waters of Lake
Michigan.

.DAY ONE...Tonight

Thunderstorms are likely late this afternoon and evening. Some
storms may be severe south of Port Washington and Little Sable
Pt.

Breezy northwest winds and a few gale force gusts are possible
tonight in the wake of a cold front. High waves are expected over
the middle and eastern half of Lake Michigan through Wednesday
morning.

.DAYS TWO THROUGH SEVEN...Wednesday through Tuesday

Breezy southwest winds may reach gale force over the north half
of the lake on Thursday. High waves will develop over the north
half and continue into Thursday night.

Cronce

www.weather.gov/mkx