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LMZ366 Expires:202312081015;;088084 Fzus63 Kmkx 080312 Glflm
open lake forecast for lake michigan national weather service milwaukee/sullivan wi 912 pm cst Thu dec 7 2023
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..
following some modest southerly gusts to around 20 knots over most of the lake through midnight central standard time, south to southwest winds with gusts up to 30 kts will gradually rebuild going into early Friday morning and last into the mid afternoon hours as low pressure of 29.3 inches moves eastward into southern ontario. Another area of low pressure will develop over illinois Friday night and move northeastward across lake michigan on Saturday. South winds will shift to the west Saturday afternoon and to the northwest on Sunday as the low exits to the northeast. Wind gusts may reach gale force for the southern half of lake michigan Saturday morning.
lmz261-362-364-366-563-565-567-868-081015- lake michigan from seul choix point to rock island passage 5 nm 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 5 nm offshore- lake michigan from charlevoix to point betsie mi 5 nm offshore to mid lake- lake michigan from point betsie to manistee mi 5 nm offshore to mid lake- lake michigan from rock island passage to sturgeon bay wi- lake michigan from sturgeon bay to two rivers wi 5 nm offshore to mid lake- lake michigan from two rivers to sheboygan wi 5 nm offshore to mid lake- lake michigan from pentwater to manistee mi 5 nm offshore to mid lake- 912 pm cst Thu dec 7 2023
sheboygan wi to pentwater mi north...
Rest of tonight..Southeast winds 10 to 20 kt increasing to 30 kt. Waves 2 to 4 ft building to 4 to 6 ft occasionally to 8 ft.
Friday..South winds to 30 kt becoming southwest 15 to 25 kt. Waves 5 to 8 ft occasionally to 10 ft.
Friday night..Southwest winds 15 to 25 kt becoming south 10 to 20 kt. Chance of rain overnight. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft.
Saturday..South winds to 30 kt becoming southwest. Rain likely in the morning, then chance of rain in the afternoon. Waves 4 to 7 ft occasionally to 9 ft.
Saturday night..West winds 15 to 25 kt becoming northwest 10 to 20 kt. Chance of rain in the evening. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft.
Sunday..Northwest winds 15 to 25 kt. Waves 4 to 6 ft occasionally to 8 ft.
Sunday night..Northwest winds 15 to 25 kt diminishing to 10 to 20 kt. Waves 3 to 5 ft subsiding to 2 to 4 ft.
Monday..West winds 10 to 20 kt becoming southwest 15 to 25 kt. Waves 1 to 3 ft building to 3 to 5 ft.
Tuesday..West winds to 30 kt. Waves 4 to 7 ft occasionally to 9 ft subsiding to 4 to 6 ft occasionally to 8 ft.

LMZ300
No data

FXUS63 KGRB 072254 AFDGRB

Area Forecast Discussion National Weather Service Green Bay WI 454 PM CST Thu Dec 7 2023

Updated aviation portion for 00Z TAF issuance

DISCUSSION
Issued at 313 PM CST Thu Dec 7 2023

SHORT TERM...Tonight and Friday

Main forecast concerns to be on small chance for drizzle or freezing drizzle to develop over northern WI later tonight, followed by extent of clouds and temperatures for Friday.

The 19Z MSAS surface analysis showed an area of low pressure over western ND with a cold front extended southward into the central Plains and a warm front extended east-southeast through southern sections of MN and WI. Visible satellite imagery indicated patches of mid-level clouds over northeast WI with clear skies farther to the west and south.

The warm front is forecast to slowly lift north tonight with eventual south winds beginning to tap gulf moisture. As temperatures slowly drop and dew points rise, expect low clouds to develop along with patchy fog after midnight. The question then becomes whether any precipitation will develop. Forecast soundings still show dry air aloft, thus drizzle/freezing drizzle would be the precipitation type if it does form at all. Most models stay dry, but feel that northern WI may see this mixed precipitation so have added this potential to the forecast. Min temperatures are forecast to bottom out in the lower 30s north, middle to upper 30s south late this evening, then slowly rise overnight as cloud cover develops. As temperatures do moderate toward daybreak, any freezing drizzle would become drizzle.

Any drizzle should end by mid-morning Friday as the warm front lifts farther north through Upper MI. Patchy fog could also linger until mid-morning before mixing out. Southwest winds and warmer air will continue over the area on Friday, however forecast soundings show a pretty stout inversion that be tough to break. If clouds hang tough, it will be hard for temperatures to significantly warm. Even if the low clouds mix out, middle and high clouds are forecast to arrive in the afternoon. For now, have max temperatures ranging from the lower to middle 40s over north- central WI, to around 50 degrees across east-central WI.

LONG TERM...Friday Night Through Thursday

The main focus remains on the system to impact the area Friday night through Saturday night, bringing a mix of rain and snow.

There has been some back and forth on whether there will be one main wave, or two separate waves which generate precip Friday night through Saturday night. Latest runs are on the two wave scenario. Lift generated from the first approaching shortwave Friday night into Saturday morning, along with proximity to the LFQ of the upper jet, will allow precipitation to begin.
Temperatures Friday night will initially be in the middle 30s to lower 40s, resulting in nearly all rain at precip onset as it spreads in from the south. Temperatures cool Saturday morning starting in the north. This will lead to a transition to snow as the second shortwave moves through mid-morning through Saturday night. QPF amounts during the snow portion of the event have lowered, which has resulted in slightly lower snow totals in this most recent forecast update. The potential for 2 inches or more is highest across far north-central Wisconsin, but these percentages are down to 10 to 30 percent. Potential for 4 inches or more is now zero. Across the rest of the area, a trace to 1 inch is the most likely scenario.

Cooler air will filter in behind this system; however, readings will still be near normal for early December. High temps from Sunday through Wednesday will range from the middle 20s to middle 30s, low temps will be in the teens and 20s.

Precipitation chances look low through the rest of the long term forecast. A clipper system moves across Canada Wednesday and Thursday. Right now, any associated precipitation remains north of the Wisconsin border, but will need to monitor in case the track drifts any farther south.

AVIATION
for 00Z TAF Issuance Issued at 438 PM CST Thu Dec 7 2023

VFR conditions are expected across the area this evening.
Overnight, the models are depicting low clouds in the MVFR or IFR category or lower to develop from 08z to 11z and linger into Friday morning. Along with the low clouds, there may be some patchy drizzle as well, possibly could be freezing drizzle from KRHI on northward. Low level wind shear will develop this evening and continue into Friday morning, generally from 200 to 220 degrees at 30 to 35 knots. CIGS should gradually improve late Friday morning and afternoon.

GRB WATCHES/WARNINGS/ADVISORIES
None.

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