Sunrise 5:49 AM   Sunset 7:46 PM Moonrise 12:00 AM   Moonset 7:41 AM

  Print   HELP   Reset   Save   Recall

LMZ779 Expires:202404272130;;468117 Fzus63 Kmkx 271501 Glflm
open lake forecast for lake michigan national weather service milwaukee/sullivan wi 1001 am cdt Sat apr 27 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 -
low pressure around 29.5 inches over northwest wisconsin will continue to gradually weaken as it moves northeast across lake superior into ontario this afternoon. Gusty south winds are expected across lake michigan today, with a few gusts approaching or reaching gale force, especially in the northeast portion of the lake.
winds will then gradually shift from southwest to northerly tonight as a cold front tracks south, but southerly winds will continue over far southern lake michigan as the front stalls. Brisk northeast winds will then prevail over central lake michigan on Sunday with lighter winds in the north, and variable winds in the south where the stalled front remains. Modest east to southeast winds will then develop over all of the lake Sunday night as the stalled front moves north as a warm front. Brisk east winds, possibly reaching gale force, are expected over the northern tip of the lake late Sunday night into Monday morning. Breezy south winds will develop over the remainder of the lake on Monday.
rounds of showers and Thunderstorms are expected tonight into Monday morning. A few of these storms could produce locally gusty winds and hail.
lmz080-669-671-673-675-777-779-870-872-874-876-878-272130- 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- 1001 am cdt Sat apr 27 2024
sheboygan wi to pentwater mi south - .
Rest of today - South winds 25 to 30 kt. Slight chance of rain showers and Thunderstorms this afternoon. Waves 6 to 9 ft occasionally to 12 ft. Tonight - South winds to 30 kt diminishing to 10 to 20 kt, then variable early morning Sunday. Chance of rain showers and slight chance of Thunderstorms in the evening, then chance of rain showers and Thunderstorms overnight. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft. Sunday - Variable winds becoming northeast 15 to 25 kt. Rain showers with a chance of Thunderstorms in the morning, then chance of rain showers in the afternoon. Waves 1 to 3 ft building to 4 to 6 ft occasionally to 8 ft. Sunday night - East winds 10 to 20 kt becoming southeast. Rain showers with a chance of Thunderstorms. Waves 3 to 5 ft. Monday - South winds 15 to 25 kt. Showers likely. Waves 4 to 7 ft occasionally to 9 ft. Monday night - Southwest winds 15 to 25 kt becoming west 10 to 15 kt. Waves 4 to 7 ft occasionally to 9 ft subsiding to 3 to 5 ft. Tuesday - West winds 10 to 15 kt backing to south 10 to 20 kt. Waves 1 to 3 ft. Wednesday - Southwest winds 10 to 20 kt becoming south. Waves 2 to 4 ft.

LMZ700
No data

FXUS63 KLOT 271445 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 945 AM CDT Sat Apr 27 2024

KEY MESSAGES

- Summer-like conditions today with high temperatures in the upper 70s to low 80s and increased humidity levels.

- Breezy today with wind gusts as high as 40-45 mph from mid- morning through the early afternoon.

- Isolated showers and thunderstorms expected to develop this afternoon with coverage increasing markedly tonight. There are lower-end chances for damaging wind gusts with this evening's storms and for localized flooding tonight.

- After a break Tuesday, an active weather pattern returns midweek with multiple periods of showers/storms expected through Friday.

UPDATE
Issued at 945 AM CDT Sat Apr 27 2024

A recent hand surface analysis shows a pair of low pressure systems, with the first near the Twin Cities and the second near the Texas panhandle. Between both lows, broad south to southwesterly flow is advecting moist and arguably humid air as well as unseasonably warm temperatures into our region with current temperatures already above the average for late April and in the upper 60s to around 70.

Earlier this morning, both the 12Z ILX and DVN RAOBs sampled a modest capping inversion based near 850mb. While continued low- level warm air advection and subtle height rises (between the parent upper-level shortwaves tied to each aforementioned surface low pressure system) should reinforce the capping throughout the day, aggressive low-level moisture advection in tandem with forecast high temperatures in the upper 70s to around 80 may nevertheless allow for free convection to develop by mid-afternoon. Indeed, modifying the 12Z DVN/ILX RAOBs with expected surface conditions this afternoon show little to no capping with some 1000-1500 J/kg of MLCAPE. For this reason, it appears prospects for at least isolated thunderstorms are increasing across our area this afternoon.

Now, just how many thunderstorms develop this afternoon will probably dictate the placement and coverage of thunderstorms overnight. In the scenario where the capping inversion holds, showers and storms would be poised to develop near a stationary front draped across eastern Iowa and southern Wisconsin this evening in tandem with the intensifying low-level jet. The result of upscale growth of a cluster or two would then be poised to move into northern Illinois and eventually northwestern Indiana after dark. Recent iterations of the NAM3 show this idea. However, if the cap erodes fully this afternoon, scattered to even widespread showers and storms may erupt near the axis of highest low-level moisture somewhere near US-24 as early as 3-4 pm, and continue more or less unabated overnight as the low-level jet intersects composite west-to-east oriented outflow. In this scenario, a localized threat for flash flooding would materialize owing to repeated rounds of thunderstorms over the same area. It's worth noting the 00Z (overnight) run of the HRRR depicted a narrow axis of 24-hour LPMM of 2-4" near US-24. While the 00Z WRF-ARW appeared to dominate the 00Z HRRR signal, the fresh 12Z HRRR and recent iterations of the experimental RRFS depict a strikingly similar evolution with training thunderstorms near or just south of US-24. Regardless of where thunderstorms do form, the strongest will be capable of producing locally damaging winds and damaging hail.

All things considered, opted to increase PoPs dramatically to the 50-60% range along and south of I-80 this afternoon to account for the threat that the cap breaks and coverage of showers and storms is much higher than originally anticipated.

Updated products have been sent.

Borchardt

DISCUSSION
Issued at 352 AM CDT Sat Apr 27 2024

Through Sunday:

After any lingering overnight convection clears the area this morning, the already breezy southerly winds will get even breezier by mid-morning as we begin to tap into 40 kt flow in the lower part of an overhead low-level jet. This will likely translate to 40-45 mph gusts being observed during a brief window of time between the mid-morning and early afternoon before the magnitude of the gusts lessens a bit as the low-level jet continues to gradually wane going into this afternoon. These southerly/south-southwesterly winds will also serve to advect in an unseasonably warm and moist air mass, characterized by summer-like dew points in the low to mid 60s and temperatures that will likely climb into the upper 70s to around 80F with the assistance of some filtered sunshine.

Height rises, large-scale subsidence on the backside of the departing upper-level trough, and the development of a capping inversion should ensure that most of our forecast area will remain dry through the daytime hours. However, by about the mid-afternoon, the capping inversion will likely be eroded as a result of surface heating, and some combination of broad isentropic ascent and low- level confluence should help isolated to scattered convection to sprout. Confidence is highest in this occurring in our southern counties, where high resolution models continue to suggest that there may be a zone of more focused ascent, but can't entirely rule out a stray shower/storm or two popping up elsewhere, so continue to carry slight chance PoPs across the entire CWA during the mid-late afternoon. There will be a plentiful amount of instability around come this afternoon (MLCAPE of up to around 2500 J/kg), so would not be surprised if a couple of storms managed to grow deep enough to support a threat for downbursts and/or hail, but the latest thinking is that the relatively broad and modest forcing for ascent should preclude the development of any overly rambunctious convection capable of making full use of the available instability.

Meanwhile, to our west and southwest, a frontal zone is expected to light up with convection during the afternoon and evening as large scale forcing for ascent increases in advance of another upper-level trough ejecting into the Great Plains. Convection that originates in Iowa and Missouri is likely to grow upscale with time and track in our general direction, with most of the latest CAM runs envisioning that at least a semi-organized multicell storm cluster will be knocking on the doorstep of our western CWA by mid-evening. While these storms are expected to lose steam with time and eastward extent, forecast soundings indicate that the degree of available buoyancy here this evening could still be adequate to support the development of new, deep updrafts along the storm cluster that would carry a threat to produce strong to severe downburst winds, particularly across our northwestern CWA This threat largely hinges upon this storm cluster developing a robust consolidated cold pool that would be able to overcome increasing nocturnal boundary layer stability, which does not appear to be a given at this time.

Of additional interest with tonight's thunderstorms is the potential for localized flash flooding. It does not have the look of an ideal flash flood setup by any means, but it does appear that storm orientation could somewhat align with storm motion vectors for a time and promote some potential for training convection. The nose of a strong low-level jet to our southwest will also pivot in our direction tonight and provide a continuous replenishment of moisture into the region, which will likely keep thunderstorms and heavy rainfall ongoing in at least part of our forecast area throughout the night. Thus, some potential for localized minor flooding does seem to exist in our forecast area tonight, and WPC's Marginal Risk in their Day 1 Excessive Rainfall Outlook continues to look appropriate for highlighting this possibility.

Shower and storm coverage is likely to diminish after daybreak on Sunday as the low-level jet diurnally weakens. However, with surface low pressure and an associated cold front still to our west, warm conveyor belt showers and storms will likely continue in some capacity in our forecast area during the day on Sunday, with the highest chances for precipitation remaining across our western counties through sunset.

Ogorek

Sunday Night through Friday:

Heading into Sunday evening upstream convection is likely across Iowa and Missouri and pushing east of the Mississippi River. This activity reaches the area by late evening. While instability will be on a weakening trend, the arrival of better forcing and a strengthening low-level jet would support a localized damaging wind and large hail threat, especially west of a McHenry to Kankakee, IL line.

A continued slower eastward progression of the surface cold front will likely allow for showers to persist into the day on Monday. Instability is much more muted compared to over the weekend, though a few thunderstorms can't be ruled out, potentially lingering into the afternoon and early evening hours east of I-57. Severe weather is not expected. Once showers exit to the east late Monday, skies clear out as weak mid-level ridging builds in allowing overnight lows Monday night to dip back into the upper 40s to lower 50s. Tuesday will be noticeably less humid as we remain between weather system. Ample sunshine and a return to southwest flow will still allow temperatures to warm well into the 70s again.

The break in the precipitation appears to be short lived as ensemble guidance continues to support a return to an active weather pattern midweek with multiple chances for showers and thunderstorms Tuesday night through Friday as multiple disturbances move within the broader northern stream quasi-zonal upper jet.

Petr

AVIATION /12Z TAFS THROUGH 18Z SUNDAY/
Issued at 640 AM CDT Sat Apr 27 2024

Key Aviation Messages: - SSW wind gusts over 30kt through early afternoon with sporadic gusts near 40kt - Patchy MVFR stratus this morning - SHRA/TSRA redevelops this evening through early Sunday AM

SSW winds will quickly increase this morning with gusts over 30kt expected through early afternoon. Sporadic gusts in the upper 30kt to near 40kt can't be ruled out. Winds ease toward sunset remaining SSW. Patches of MVFR stratus may move into the area this morning.

Isolated showers/storms may attempt to develop as early as this afternoon, especially near and south of I-80, though confidence remains too low for a formal TAF mention of TS during this period. The thunder potential increases mid-to-late evening, however, when model guidance continues to depict a complex of showers and thunderstorms expanding across the area. While confidence on the start time is on the lower side (and will be dependent upon where and when upstream convection develops), confidence in thunderstorms is high enough to prevail VCTS through the overnight hours with a targeted TEMPO groups overnight when the greatest coverage is anticipated along with any associated IFR/near-IFR vsby/cig reductions.

Petr

LOT WATCHES/WARNINGS/ADVISORIES
IL...None.
IN...None.
LM...Small Craft Advisory until 10 PM CDT this evening for the IL and IN nearshore waters.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


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

Chicago, IL,