Sunrise 5:59 AM   Sunset 7:42 PM Moonrise 2:28 PM   Moonset 4:12 AM

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LMZ522 Expires:202404181300;;940045 Fzus53 Kgrb 180636 Nshgrb
nearshore marine forecast national weather service green bay wi 136 am cdt Thu apr 18 2024
for waters within five nautical miles of the shore on lake michigan
lmz521-522-181300- green bay south of line from cedar river to rock island passage and north of a line from oconto wi to little sturgeon bay wi- green bay south of line from oconto wi to little sturgeon bay wi- 136 am cdt Thu apr 18 2024
Overnight - W wind 10 to 15 kts. Mostly cloudy. Waves 1 to 3 ft.Today - W wind 5 to 10 kts backing sw in the afternoon. A chance of rain showers. Waves 2 ft or less. Tonight - SW wind 5 to 10 kts veering W 10 to 20 kts after midnight. Mostly cloudy in the evening then clearing. Waves 1 to 3 ft. Friday - W wind 10 to 20 kts with gusts to around 30 kts. Partly cloudy. Waves 1 to 3 ft building to 2 to 4 ft in the late morning and afternoon. A small craft advisory may be needed.

LMZ500
No data

FXUS63 KGRB 180351 AFDGRB

Area Forecast Discussion National Weather Service Green Bay WI 1051 PM CDT Wed Apr 17 2024

Updated aviation portion for 06Z TAF issuance

KEY MESSAGES

- Showers and a few thunderstorms this afternoon. Stronger showers and storms could produce wind gusts over 40 mph. Locally heavy rain is possible in any of the stronger thunderstorms.

- Break in rain by late this evening, but more showers return late tonight into Thursday, mainly south of Highway 29.

- Friday looking windy with westerly winds gusting to 30 to 40 mph, especially central and southern areas.

DISCUSSION
Issued at 249 PM CDT Wed Apr 17 2024

Short Term...Tonight and Thursday

Radar and water vapor imagery are showing a low pressure system slowly tracking northeast across northeast WI this afternoon keeping scattered rain showers across the region. These light to moderate showers will continue through the rest of this afternoon. Mesoanalysis shows an area of weak surface CAPE (100- 400 J/kg) and increasing surface to 1.5 km lapse rates of 7- 7.5 C/km across the Fox Valley that may support a few weak surface based thunderstorms later this afternoon, but severe weather is not anticipated.

As the aforementioned low pressure system tracks northeast out of the region this evening expect rain shower activity to come to an end shortly after sunset. Gusty northwest winds will be possible this evening on the backside of the low with a few gusts to 25- 35 mph possible, strongest across central WI. A weak ridge moving across the area overnight should keep conditions dry. Dry air aloft may lead to some brief clearing early Thursday morning, but skies are expected to quickly fill back in ahead of a compact mid- level low developing across the Northern Plains. Low temperatures tonight are expected to drop into the mid 30s to low 40s region wide.

Another round of rain is expected to arrive Thursday morning as the previously mentioned mid-level low and a 100-110kt upper level jet track into the western Great Lakes. Don't expect much in the way of thunderstorms Thursday with almost no instability and meager mid-level lapse rates. High temperatures Thursday are expected to reach the low to mid 50s in most location.

Long Term...Thursday Night Through Wednesday

Precipitation...A few showers may clip east-central WI on Thursday evening. These will be occurring along southern edge of upper level jet and to the north of weak low pressure wave crossing the western Ohio Valley. Majority of deeper moisture shifts east overnight as a leading cold front moves through, taking any lingering showers out of the area. Upstream is a large deep upper trough that will be settling east- southeast by Friday morning. Main sfc low tied to the trough will be well to the north of Lake Superior, if not to James Bay, so in general ascent for precip over our area Friday will be limited. May be just enough low-level moisture and cold air advection for a few rain and snow showers over far northern WI, though westerly flow will not be favorable for much precip. Winds veering to northwest Friday night with continued cold air advection in the deeper trough may result in increasing snow showers, especially for Vilas County. A touch of late season snow accumulation could result, though the somewhat higher probabilities from the NBM of 0.5 inch or more of snow along the WI/Upper MI border seen overnight have come down some compared to previous runs. NW flow persists on Saturday and Saturday morning is when the lowest H85 temps of -8c to -10c are seen into northern WI. Net result will be continued chance of some light snow showers Saturday morning along with good deal of lingering clouds, even away from northern WI.

Otherwise, the weekend will be mainly dry as high pressure slides across. The next chance for precip looks to arrive late Monday into Tuesday. Temps look warm enough for just rain this time around. Still have to nail down details though.

Winds...Westerly winds will increase on Friday due to strong winds (35 to 45 kts) in the low to mid levels to the south of the main low pressure system. Soundings show steep low-level lapse rates, deep mixing will tap into these stronger winds. Good landing point now is west wind gusts 30-40 mph over especially central and southern areas. If cloud cover is not as robust on Friday for these southern areas, could even see a few locations reaching near advisory level gusts of 45-50 mph. Weakening low-level lapse rates will allow the winds/gusts to diminish on Friday night.

Temperatures...Following a lead cold front that moves through on Thursday night, below normal temperatures are expected Friday and Saturday. The largest departures for high temps will be from central to north-central WI with readings 7-10 degrees below normal. Departures will not be as significant from the Fox Valley to the lakeshore.
Temps will then rise to normal or slightly above normal for Sunday into early next week, with highs mainly in the 50s, though some readings in the 60s will make an appearance on Monday.

AVIATION
for 06Z TAF Issuance Issued at 1050 PM CDT Wed Apr 17 2024

A mix of mainly MVFR/IFR conditions will continue through the late evening hours, with a few VFR beginning to push into central WI.
Any lingering drizzle or light rain over far northeast WI and northern Door County will exit by midnight as low pressure pushes away from the area. Some fog is possible over far northern WI through the late evening and early overnight hours. Ceilings are expected to lift to VFR late tonight into very early Thursday, but lower clouds (mainly MVFR), along with areas of light rain, will return from the southwest Thursday morning as an upper level disturbance and frontal boundary approach.

W/WNW winds will continue to slowly ease overnight, but a few gusts to 20 kts will remain possible. W/WSW winds are expected on Thursday with gusts to around 20 kts in the afternoon.

GRB WATCHES/WARNINGS/ADVISORIES
None.

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