Sunrise 5:21 AM   Sunset 8:14 PM Moonrise 5:34 PM   Moonset 3:45 AM

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LMZ645 North Point Light To Wind Point Wi- 106 Pm Cdt Mon May 20 2024
.severe Thunderstorm watch 267 in effect until 5 pm cdt this afternoon - .
Rest of today - Southeast wind 10 to 15 knots veering south late in the afternoon. Rain showers likely early in the afternoon. Chance of Thunderstorms through the day. Rain showers late in the afternoon. Waves around 1 foot. Tonight - West wind 5 to 10 knots with gusts to around 20 knots becoming west 5 to 10 knots late in the evening, then veering northwest after midnight veering east early in the morning. Chance of showers and Thunderstorms through around midnight. Waves around 1 foot. Tuesday - East wind 5 to 10 knots veering southeast late in the morning, then rising to 10 to 15 knots in the afternoon. Slight chance of showers and Thunderstorms through the day. Waves around 1 foot. Tuesday night - Southeast wind 15 to 20 knots veering south late in the evening, then becoming 15 to 25 knots after midnight veering southwest early in the morning. Rain showers and a chance of Thunderstorms through the night. Waves 3 to 4 feet.

LMZ600
No data

FXUS63 KMKX 201801 CCA AFDMKX

Area Forecast Discussion...CORRECTED National Weather Service Milwaukee/Sullivan WI 101 PM CDT Mon May 20 2024

KEY MESSAGES

- Confidence in strong to severe storms has increased this afternoon. A Severe Thunderstorm Watch is in effect for portions of the area until 5 PM.

- Large hail and damaging winds are the primary concerns in this afternoon's storms, though a few spin-up tornadoes can't be ruled out.

- While there remains uncertainty on the exact specifics of the severe weather threat Tuesday, there remains a higher chance (risk 3 out of 5) for severe weather on Tuesday with all modes of severe weather (large hail, damaging winds, and tornadoes)
possible. Overnight storms Monday into Tuesday and how they track/evolve over IA/IL will impact the development and environment Tuesday afternoon and evening.

UPDATE
Issued 1245 PM CDT Mon May 20 2024

.SEVERE THUNDERSTORM WATCH 267 IN EFFECT UNTIL 5 PM THIS EVENING FOR PORTIONS OF SOUTHEASTERN WISCONSIN...

In coordination with the Storm Prediction Center & neighboring offices, a severe thunderstorm watch has been issued for the southeastern corner of the area until 5:00 PM this evening. This watch includes the entirety of the Milwaukee metro. Madison & Dane County are not included in the watch. Developing along & ahead of an MCV approaching from the west, scattered thunderstorm development is anticipated through early to mid afternoon, particularly within within an area of clearing skies that has materialized from Janesville to Watertown & points east to the lakeshore. Satellite & radar trends have shown multiple attempts at initiation over the last 45-60 minutes, with preliminary storms struggling to maintain intensity. Expect that strength will steadily increase with continued surface heating over the watch area, with large hail and damaging wind gusts being the primary concerns. Despite the primary wind/hail hazards, low level shear is supportive for isolated tornadoes, with the MKX VWP depicting clockwise-turning hodographs and 200+ m2/s2 of storm-relative helicity in the lowest kilometer. Any persistent cells will thus need to be monitored for this isolated potential, particularly in any locations where winds are backed out of the southeast. Have multiple ways to receive warning information through this afternoon over southeastern Wisconsin.

Quigley

SHORT TERM
Issued 423 AM CDT Mon May 20 2024

Today through Tuesday night:

Early this morning a band of rain/storms is moving through southern Wisconsin. This initial band of showers is expected to be on the weaker side and will continue to diminish/weaken as it traverses east away from the LLJ and shortwave trough. This line of showers is currently supporting this thought process well as it has been very outflow dominate over the last few hours.
Behind this band, further up stream, is the MCV feature that brings our concern for severe weather today. The lull between the ongoing rain the MCV will be a big determining factor in how much sfc instability we will have. The MCV is currently being supported by the LLJ and shortwave trough approaching the state.
The best chances for strong to severe storms late this morning into the afternoon will likely be across southeastern and eastern Wisconsin where conditions are currently dry. The ongoing line is likely to weaken significantly early this morning. This should keep the environment primed for when the MCV rolls through. Overall the biggest threat from any stronger storms will be hail. Can't rule out some gusty winds, but thats going be more likely from towering storms that fall apart quickly than anything else.

Tuesday brings the next chance for rain and storms as the next upper level shortwave moves through. This next system will be more robust than the previous provide southern Wisconsin with a greater chance for severe weather. There are two "rounds" of rain/storms expected Tuesday, one along the warm front and a second along the cold front. The cold front will be the main driver for our severe potential. Overall the environmental setup will have decent moisture, great low level instability and some upper level synoptic support. 0-3km shear will be high and hodographs are taking on that nice curved feature. This allows all storm modes to be possible with the main hazard concerns being winds and tornadoes. Tornadic potential at this point leans toward the short-lived quick spin up type.

Now the bigger issues with the amount of synoptic support with this shortwave and the warm front. Uncertainty in how far north the warm front will move north and the timing this will occur are the biggest factors. If these two "rounds" run together then it would be hard for the environment to recover and it would reduce the severe potential. On the other hand, if the warm front surges northward with a significant break between it and that cold front. Then the door opens up for more supercellular like behavior along and ahead of the cold front. Behind the front, quieter weather is expected to return.

Patterson

LONG TERM
Issued 423 AM CDT Mon May 20 2024

Wednesday through Sunday:

The cold front and dry slot will be clear of southern WI by Wednesday morning, per the majority of models and ensembles. There may be a few strato-cu showers toward central WI with any wrap- around precip from the exiting upper low. Otherwise, expect gusty westerly winds and cooler temperatures around 70.

Thursday through Sunday high temps will also be in the lower to mid 70s, with lows in the lower 50s, much more seasonal for this time of year. The next chance for showers and thunderstorms will arrive Friday afternoon or night to kick off Memorial Day Weekend.
This is associated with an upper low tracking across southern Canada and remnant vorticity advection over southern WI. As the case has been lately, the GFS goes crazy with the QPF and also brings the front through WI earlier than the ECMWF (by at least 12 hours). The low level jet, warm air advection, and a weak shortwave justify our small chances for showers and storms Fri evening.

One more shortwave digging through the Plains is expected to swing across WI on Saturday. The ECMWF came in with a similar idea to the GFS for the 00z run. While there is still plenty of time to work out the details, the risk of showers and storms sometime Saturday-Sat nt is there. Weak ridging moves in Sunday, so precip chances are much lower for that period.

Cronce

AVIATION
Issued 917 AM CDT Mon May 20 2024

Convection will impact the terminals at times today, with the highest chance for stronger storms occuring this afternoon at Janesville, Kenosha, and Milwaukee. MVFR/IFR will be possible in and around any convection, with VFR otherwise prevailing. Winds will briefly become gusty from the southwest over southeastern Wisconsin this afternoon as well.

Limited shower/thunderstorm coverage is expected this evening and overnight. Winds will be light from the west, trending light and variable at times overnight.

Boxell

MARINE
Issued 423 AM CDT Mon May 20 2024

Light and variable winds over Lake Michigan will continue early this morning before shifting to southeasterly. Winds will become southwest to westerly by this afternoon as a weak low pressure system traverses the Great Lakes Region. Monday night into Tuesday southeast winds return as another stronger low pressure system advances from the Central Plains. This low pressure system will deepen as it moves into the Great Lakes Region causing southerly winds to increase. A Small Craft Advisory will likely be needed Tuesday night into Wednesday for the breezy southwest winds.

Patterson

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

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