Sunrise 5:22 AM   Sunset 8:13 PM Moonrise 5:30 PM   Moonset 3:42 AM

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LMZ878 Expires:202405201515;;527510 Fzus63 Kmkx 200750 Glflm
open lake forecast for lake michigan national weather service milwaukee/sullivan wi 250 am cdt Mon may 20 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 -
southeast winds this morning will become more southerly by this afternoon as a weak area of low pressure around 29.7 inches tracks over wi and lake michigan. Expect to see more west to southwesterly component of the winds briefly overnight tonight. Winds will turn more south to southeasterly again Tuesday. Breezy southerly winds are expected as a deepening low pressure around 29.4 inches approaches the upper great lakes region and tracks northeast into Wednesday. There looks to be periods of Thunderstorms over the lake, especially southern portions Monday through Wednesday morning.
lmz080-669-671-673-675-777-779-870-872-874-876-878-201515- 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- 250 am cdt Mon may 20 2024
sheboygan wi to pentwater mi south - .
Today - Southeast winds 10 to 15 kt becoming south 10 to 20 kt. Slight chance of showers and Thunderstorms this morning, then chance of showers and Thunderstorms this afternoon. Waves 1 to 3 ft. Tonight - Southwest winds 10 to 20 kt diminishing to 5 to 10 kt. Chance of showers and Thunderstorms in the evening, then slight chance of showers and Thunderstorms overnight. Waves 1 to 3 ft. Tuesday - Southeast winds 5 to 10 kt increasing to 10 to 20 kt. Chance of showers in the morning. Waves 1 to 3 ft. Tuesday night - South winds to 30 kt. Showers likely with a chance of Thunderstorms in the evening, then chance of showers and Thunderstorms overnight. Waves 3 to 5 ft building to 6 to 9 ft occasionally to 12 ft. Wednesday - Southwest winds to 30 kt diminishing to 15 to 25 kt. Waves 5 to 8 ft occasionally to 10 ft subsiding to 4 to 7 ft occasionally to 9 ft. Wednesday night - West winds 10 to 20 kt. Waves 3 to 5 ft. Thursday - West winds 10 to 20 kt becoming southwest. Waves 2 to 4 ft. Friday - East winds 10 to 20 kt. Waves 1 to 3 ft.

LMZ800
No data

FXUS63 KIWX 200959 AFDIWX

Area Forecast Discussion National Weather Service Northern Indiana 559 AM EDT Mon May 20 2024

KEY MESSAGES

- Chance of storms this afternoon into tonight. Widespread severe weather is not expected, but an isolated storm may have a hail or wind threat especially from northwest Indiana into southwest Lower Michigan.

- Strong to possibly severe thunderstorms still appear possible late Tuesday night and possibly again Wednesday afternoon or evening. Both of these periods are marked by low confidence in severe weather. Best chance of severe weather across northwest Indiana into southwest Lower Michigan late Tuesday evening into the overnight hours.

- High temperatures well into the 80s today and Tuesday, cooling back into the mid and upper 70s for Thursday and Friday.

- Lull in precip chances for Thursday, but additional chances of showers and thunderstorms next weekend.

DISCUSSION
Issued at 407 AM EDT Mon May 20 2024

Challenging convective forecast through midweek, with several potential rounds of convection, but all of relatively low confidence in terms of extent and severe potential.

An upper level ridge axis will begin to shift off to the east today allowing some return southerly low level flow. This southerly flow will allow the narrow southwest-northeast oriented low level theta-e maximum to migrate northward into Lower Michigan today. A few showers or isolated thunderstorms could accompany the northward retreat of this weak theta-e gradient later this morning or into the mid afternoon hours. Of greater concern will be monitoring a compact mid level short wave which is being enhanced largely by ongoing central Plains/Corn Belt convection. This convectively enhanced vort appears to be positioned across northwest Missouri as of 0730Z and will continue to track north northeast into southern Wisconsin. Background shear will be on the marginal side today with the exception of near this diabatically enhanced short wave which should be accompanied by small area of better deep layer shear. Near term guidance is exhibiting some fairly big differences in near sfc/sfc moisture quality and low level mixing depths today, partly in response to sensitivity in nailing down the exact track of this small scale vort max.

Best chances of scattered showers and storms today appear to be across west-northwest locations by late afternoon/early evening on the southern periphery of this vort max. Best low level moisture transport downstream of this vort max still appears to reside across northern Illinois where a Slight Risk of severe storms persists today (Marginal Risk for NW Indiana to south central Lower MI).
While instability may be a bit more tempered into Lower Michigan/northern Indiana, fairly large low level dew point depressions and steep low level lapse rates could yield some isolated strong to near severe wind gusts across the northwest late this afternoon into early this evening. Some hail is also possible but will be dependent on the extent of low level mixing and instability magnitudes. Threat for isolated severe weather today should reside in the 20Z-03Z timeframe. Otherwise today a continuation of the much above normal temperatures is expected with low level thermal progs supporting highs in the mid 80s to around 90. The biggest change from yesterday will be warmer conditions across NW Indiana and SW Lower Michigan where offshore flow will promote warmer temperatures closer to Lake Michigan.

For tonight, low/mid level flow on southern periphery of departing small scale short wave could briefly become frontogenetic in nature helping to extend scattered showers and isolated storms into the late evening and early overnight hours before diminishing. Mild temps for tonight with lows only dropping into the mid 60s.

For Tuesday, mid level ridge will begin to shift across eastern Great Lakes with northward retreat of developing low level warm front as more substantial large scale upper level trough digs across the northern Rockies. Fairly steep mid level lapse rates and some low level convergence with warm front could promote a few isolated stronger cells north of US Route 30 during the late morning/afternoon hours. A weak small scale short wave may also be progressing through the ridge during the day Tuesday. Given rather nebulous forcing signals, will continue with 20-30% PoPs through much of the day. Very warm conditions continue Tuesday with highs in mid-upper 80s.

Tuesday night will feature the greatest risk of severe weather this forecast cycle, but uncertainty remains for this period.
Cyclogenesis across southern MN should be ongoing Tuesday evening with a robust 50+ knot low level jet nosing into eastern Iowa/northern Illinois/southern Wisconsin during the afternoon and early evening hours. Storms are likely to develop along cold front and in pre-frontal forced zone across the Mid MS Valley Tuesday afternoon/evening with focus for this convection shifting into western Great Lakes late in the evening. Shear profiles will increase from west to east locally as the mid/upper level height evolution occurs Tuesday, but development of some convective inhibition for surface/near surface parcels given late timing of this forcing offers some uncertainty as to the longevity of this convective line into the local area.
Stronger upper forcing may also be lifting northeast across the Upper Midwest which will keep strongest height falls northwest of the local area. Steep mid level lapse rates and outflow boundary from better organized upstream convection could be compensating factors to allow some convective organization to persist into northwest half of the area late Tuesday night.
Scattered damaging wind gusts appears to be the main threat, but cannot completely rule out an isolated tornado far west with a spin-up possible along potential convective line given strengthening 0-3km westerly shear.

Surface cold front will be slow to move across the area on Wednesday as first stronger vort lifts northeast and secondary vort max approaches from the central Plains. Some moderate instability is expected to develop along a corridor from southern Missouri into northwest Ohio by late Wednesday afternoon with 35-45 knots of deep layer shear. Some question as to timing of initiation as large scale lift from secondary vort max could provide for favorable initiation after peak heating leading to some lower confidence in severe weather coverage. The southeast half of the area remains in Day 3 Slight Risk of severe storms for wind/hail threat.

Low level anticyclone shifts across the area on Thursday with dry conditions, but quick return to southerly flow Friday in advance of additional eastern Pacific waves in low amplitude flow will promote more chances of showers and storms into next weekend.
Temps will cool back into the 70s for Thursday and Friday with much lower dew points by this time.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
Issued at 556 AM EDT Mon May 20 2024

VFR conditions prevail through the first half of the day, with operationally insignificant clouds at or above 15 kft. Southerly winds will start to pick up after 15Z this morning, with gusts up to 15 to 20 knots possible. Have added in a low chance for a shower or storm into the KSBN TAF starting at 23Z, as a potent upper level shortwave moves through the area this afternoon/evening and may spark scattered showers and storms. A few storms may have small hail and gusty winds. Opted to keep a mention for a shower or storm out of the KFWA TAF for now, but it may be needed in subsequent TAF updates. Main shower/storm activity will be between 21-03Z.

IWX WATCHES/WARNINGS/ADVISORIES
IN...None.
OH...None.
MI...None.
MARINE...None.

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