Sunrise 5:38 AM   Sunset 7:49 PM Moonrise 3:29 AM   Moonset 2:36 PM

  Print   HELP   Reset   Save   Recall

LMZ779 Expires:202405040330;;564137 Fzus63 Kmkx 031953 Glflm
open lake forecast for lake michigan national weather service milwaukee/sullivan wi 253 pm cdt Fri may 3 2024
for waters beyond five nautical miles of shore on lake michigan.
waves are provided as a range of significant wave heights, which is the average of the highest 1/3 of the wave, along with the average height of the highest 10% of the waves which will occasionally be encountered.
Synopsis -
high pressure of 30.1 inches with variable light winds will turn more easterly through this evening and overnight. Moisture will increase heading into tomorrow ahead of a frontal passage tomorrow afternoon. Some showers and storms are possible in the afternoon with the passage of the front. Following the cold front, winds will turn westerly and could become breezy Saturday night into Sunday as a 30.05 high pressure moves into the area. Sunday will start on the breezy side before the winds slowly subside heading into the afternoon and evening.
lmz080-669-671-673-675-777-779-870-872-874-876-878-040330- lake michigan from michigan city in to st. Joseph mi 5 nm offshore to mid lake- lake michigan from sheboygan to port washington wi 5 nm offshore to mid lake- lake michigan from port washington to north point light wi 5 nm offshore to mid lake- lake michigan from north point light to wind point wi 5 nm offshore to mid lake- lake michigan from wind point wi to winthrop harbor il 5 nm offshore to mid lake- lake michigan from winthrop harbor to wilmette harbor il 5 nm offshore to mid lake- lake michigan from wilmette harbor il to michigan city in 5 nm offshore to mid lake- lake michigan from whitehall to pentwater mi 5 nm offshore to mid lake- lake michigan from grand haven to whitehall mi 5 nm offshore to mid lake- lake michigan from holland to grand haven mi 5 nm offshore to mid lake- lake michigan from south haven to holland mi 5 nm offshore to mid lake- lake michigan from st. Joseph to south haven mi 5 nm offshore to mid lake- 253 pm cdt Fri may 3 2024
sheboygan wi to pentwater mi south - .
Tonight - Northeast winds 10 to 15 kt becoming east. Waves 1 to 2 ft. Saturday - East winds 10 to 15 kt becoming southeast 10 to 20 kt. Waves 1 to 3 ft. Saturday night - South winds 10 to 15 kt veering to north 10 to 20 kt. Showers likely in the evening. Waves 1 to 3 ft.Sunday - North winds 10 to 20 kt. Waves 2 to 4 ft. Sunday night - North winds 10 to 20 kt becoming northeast 10 to 15 kt. Waves 2 to 4 ft subsiding to 1 to 3 ft. Monday - East winds 10 to 15 kt increasing to 10 to 20 kt. Waves 1 to 3 ft. Monday night - East winds 10 to 20 kt becoming southeast 15 to 25 kt. Waves 1 to 3 ft building to 2 to 4 ft. Tuesday - Southeast winds 15 to 25 kt becoming south. Showers with a chance of Thunderstorms. Waves 3 to 5 ft. Wednesday - Southwest winds 10 to 20 kt becoming south. Waves 2 to 4 ft.

LMZ700
No data

FXUS63 KLOT 032342 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 642 PM CDT Fri May 3 2024

KEY MESSAGES

- A dry and cool night is in store with overnight lows in the mid to upper 40s.

- Tomorrow (Saturday) will be warm with highs in the upper 70s to lower 80s, and increasing chances (60 to 70%) for showers and thunderstorms in the evening especially across northern Illinois.

- Periodic shower and thunderstorm chances next week, with some potential for strong to severe storms Tuesday.

DISCUSSION
Issued at 200 PM CDT Fri May 3 2024

Through Saturday night:

A surface high pressure system continues to meander through the Lower Great Lakes region and is leading to mostly sunny skies, light north to northeasterly winds, and generally pleasant temperatures (at least away from Lake Michigan).

With our area on the western flank of the surface high tonight, quiet conditions will prevail. Light winds, clear skies, and a dry airmass will facilitate efficient radiational cooling and allow for overnight lows to fall into the mid to upper 40s.

Tomorrow, low-level flow will turn southeasterly and eventually southwesterly as the surface high pulls further away to the east and an upper-level short-wavelength trough approaches from the west. Low- level moisture advection will allow for humid air across central Illinois and Indiana to quickly return northward and into our area by mid-afternoon. Even with filtered sunshine, the advection of a plume of seasonably warm 850mb temperatures near +13C (into which the boundary layer will build) will help boost afternoon highs into the upper 70s to lower 80s.

Chances for showers and thunderstorms will increase during the afternoon hours in two apparent waves. The first will be with an axis of remnant convection (originating from the Plains tonight), due to arrive sometime in our area early tomorrow afternoon. An ensemble of CAM guidance suggests the leading axis of showers and storms may outrun the best forcing provided by the upper-level shortwave and an associated cold front lagging to the west, and fight a pocket of dry mid-level air in place across the Lower Great Lakes. As a result, chances for showers and storms appear higher later in the afternoon and toward evening along the cold front as it moves across the area (50 to 70% chance from west to east ahead of the cold front). With the upper-level shortwave and associated jet streak expected to lift northeastward toward the Upper Peninsula of Michigan (e.g.
remain somewhat displaced from the instability axis further to the south across our area), any convective cell tomorrow afternoon and evening should behave in a "pulse" like fashion with overall limited storm-scale organization. As a result, the main threats with any storm tomorrow will be locally gusty winds, small hail, downpours, and lightning strikes, similar to yesterday (and consistent with a level 1/5 threat for severe weather). In all, tomorrow looks like another quintessential spring-like day.

Coverage of showers and storms will decrease after sunset as the cold front approaches northwestern Indiana. Temperatures behind the front will fall into the upper 40s (northwest) to mid 50s (southeast) early Sunday morning as northwesterly winds become predominant.

Borchardt

Sunday through Friday:

Next week is shaping up to be a fairly wet and active pattern.

Starting Sunday, as an upper level low drops southward into Northern California from the Bay of Alaska (more on this later), a surface low over Hudson Bay is forecasted to continue to move east drawing the cold front east out of the forecast area. There may be some lingering showers on Sunday morning, particularly over northwest Indiana, but potentially extending as far back to I-55. However, improving and drier conditions are expected through Sunday. Temperatures are expected in the upper 60s and 70s away from the lake, but with cooler northerly air over Lake Michigan, the immediate shoreline may remain in the 50s.

On Monday, the low over Northern California is expected to weaken slightly and passes over the Rocky Mountains. Ahead of of it, another upper level wave will pass over Northern Illinois. Models are disagreeing on the overall strength of the wave. The GFS is leaning deeper with an brief closed low aloft developing, where the Euro and the Canadian depict broader waves. Moisture availability seems limited though over most of the area north of I-80. With some weak lobes of vorticity that pass over, there is a chance for some light showers to pass over, but confidence remains low as it should mostly stay south of the area as temperatures warm back into the 70s, with low 60s on the shoreline.

There is fairly good model agreement that the upper level low will eject out of the Rockies over west central Montana overnight Monday into Tuesday morning while deepening. Strong surface cyclogenesis is expected to take place in the Northern Plains on Tuesday; however, where and how the low develops will largely drive what unfolds on Tuesday, and models are wildly disagreeing on that. There is a strong 300 mb jet that will develop just to the south of the upper level low, with its left exit region around or just north of northeastern Illinois, which will could assist in providing additional synoptic lift, though the exact placement of the jet will have to be monitored over time. But even models are disagreeing with the strength of the jet in addition to its exact placement. Regardless, strong mid level steering flow will draw up anomalously large precipitable water values into Illinois with dew points temperatures expected in the low to mid 60s.

After a weak boundary pushes through Tuesday morning providing the first chance for rain, temperatures are projected to increase behind the front into the upper 70s and 80s. With better instability, showers and thunderstorms are expected Tuesday afternoon and evening. While models are suggesting the strongest shear and instability a little farther south in Central Illinois and the Ohio River basin, there is the potential for strong to even severe storms locally on Tuesday.

By Wednesday, the upper level low over the Northern Plains is projected to eventually start to weaken; however, a positively tilted trough axis will remain over Plains. With persistent southerly warm air advection, there is a risk for another round of showers and storms on Wednesday. Once again though, models are still keeping higher moisture content and stronger instability to the south over the Ohio River Valley as the jet core aloft shifts slightly over Southern Wisconsin. Perhaps the risk for stronger to severe storms will remain south of I-80 on Wednesday, but it will be close enough to be monitored.

Beyond Thursday, there is much more uncertainty on exact timing of showery activity. However, both Euro and GFS ensembles are suggesting the upper level trough to continue to broaden and trudge eastward from Thursday through Sunday. With lingering moisture in the area and lobes of vorticity passing around the upper level trough, there could be periods of showers from Thursday through Saturday. It is not expected to be a complete wash out as there should be breaks from the rain at times, but it remains too far out for complete understanding on timing, so the forecast maintained a 20 to 40 percent chance for rain through Saturday morning.

DK

AVIATION /00Z TAFS THROUGH 06Z SATURDAY/
Issued at 642 PM CDT Fri May 3 2024

Forecast concerns for the terminals...

- Low chance for shallow fog tonight into Saturday morning

- Scattered showers and thunderstorms Saturday afternoon and evening, a few of which could produce gusty winds and hail

High pressure will remain overhead tonight which will promote mostly to completely clear skies and light easterly winds generally under 5 kts. However, there is a small chance (<10%)
for some shallow fog to develop late tonight into early Saturday morning as low-level moisture begins to increase, primarily outside of the Chicago terminals. Furthermore, there is a signal amongst some guidance that low stratus may develop over southern Lake Michigan and advect into northeast IL Saturday morning, but given lake temperatures in the low to mid-50s and the warmer airmass forecast to move over the lake confidence is very low on these clouds occurring.

Winds will become southeasterly Saturday morning and then southwesterly Saturday afternoon ahead of a cold front which will allow for the development of scattered showers and thunderstorms late Saturday afternoon and evening. Widespread severe weather is not expected, but conditions do look at least modestly favorable for a few stronger storms which may produce locally gusty winds and/or hail. While confidence on showers/storms is relatively high, forecast soundings do show some capping in place which may limit storm coverage. Therefore, have decided to handle this potential with PROB30s at ORD, MDW, and RFD for now. It should be noted that while I do expect showers and storms to be a concern for DPA and GYY, the arrival of storms is forecast to be after the conclusion of their respective TAF periods. Thus, have maintained dry forecasts at DPA and GYY but will need to add showers/storms with the 06z issuance.

Yack

LOT WATCHES/WARNINGS/ADVISORIES
IL...None.
IN...None.
LM...None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Chicago, IL,