Sunrise 5:42 AM   Sunset 7:56 PM Moonrise 1:21 AM   Moonset 9:24 AM

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LMZ522 Green Bay South Of Line From Oconto Wi To Little Sturgeon Bay Wi- 401 Am Cdt Mon Apr 29 2024
.dense fog advisory in effect until 1 pm cdt this afternoon - .
Early in the morning - E wind 5 to 10 kts. Patchy dense fog. A chance of rain showers. Waves 2 ft or less. Today - E wind 5 to 10 kts. Patchy dense fog in the morning. A chance of rain showers. A slight chance of Thunderstorms in the afternoon. Waves 2 ft or less. Tonight - SW wind 5 to 10 kts. Mostly cloudy in the evening then becoming partly cloudy. Waves 2 ft or less. Tuesday - W wind 5 to 10 kts. Partly cloudy in the morning then clearing. Waves 2 ft or less. Tuesday night - S wind 10 to 20 kts. Light rain showers likely after midnight. Waves 2 ft or less.

LMZ500
No data

FXUS63 KGRB 290904 AFDGRB

Area Forecast Discussion National Weather Service Green Bay WI 404 AM CDT Mon Apr 29 2024

Forecast discussion for routine morning forecast issuance

KEY MESSAGES

- Scattered showers will continue through late today before ending this evening. There is a small chance for thunderstorms this afternoon over east-central and northeast Wisconsin.

- Due to recent rainfall, rivers and streams will be on the rise through midweek, with a few of them possibly reaching bankfull stage.

- Lingering higher waves will result in conditions hazardous to small craft this morning on the central Bay and also on the Lake from Sturgeon Bay to Washington Island. Dense fog is possible over all the waters into this afternoon.

- There is a chance of showers and a few thunderstorms Tuesday night. Additional rain and thunderstorm chances are possible at times from late Wednesday night through Friday.

DISCUSSION
Issued at 403 AM CDT Mon Apr 29 2024

Short Term
Today
Tonight...and Tuesday

Shower, thunder chances and temps today are main forecast issues.

Sharp shortwave trough is lifting across the northern Plains while sfc low is over southwest Minnesota. Warm front tied to the low is just beginning to lift into southern Wisconsin. Otherwise, the NE flow enhanced by cool Lake Michigan and the rain that has occurred at times since midday on Sunday has resulted in very stable low- levels over much of Wisconsin. Thus, no thunder has occurred in the cwa into early this morning. Rain being more off than on early this morning has led to some patchy dense fog. The fog is more widespread across the bay and lake and right along adjacent shorelines.

Shortwave trough reaches northern Minnesota late today with occluding sfc low making its slow trek to western Upper Michigan. Scattered showers forming due to isentropic ascent/moist low-level advection moving toward central Wisconsin should expand as they lift northward as the forcing links up with weak elevated instability over the area.
Highest pops this morning will be north and northeast. Chancy pops otherwise. Warm front will move northward across the badger state through the day, but given occluding low and wealth of cool/moist air on east/southeast winds ahead of the front think the push northward will be sluggish, only getting into northeast Wisconsin mid to late afternoon. High temps will be *highly* dependent on frontal position this afternoon. Just take a look at wide varying MOS guidance at GRB which ranges from a high of 55 on the NAM MOS to a high of 66 on GFS MOS. Think the front makes it past GRB so went toward the GFS MOS, but realize there is higher than normal bust potential for highs today with the sharp front in the vcnty.
Farther southwest toward ISW and OSH, readings will close in on 70. North-central will see highs into the mid 50s as will Door County where cool east flow ends latest.

Cold front south of the low will swing into east-central and northeast Wisconsin mid to late afternoon. MLCAPEs of at least 500j/kg and effective shear well over 40 kts makes it prudent to continue to include and slightly bump up TS mention. An isolated strong storm is not out of question, though extent of shear and dry air in mid levels may be too much given the forecast CAPE.
Will be something to watch though.

Rest of short term more straight forward. Lingering smallish pops near the U.P. border early tonight as the occluded low moves past, but otherwise dry as the system gradually pulls away. Tuesday is dry as high pressure crosses. Unmodified W/SW low-level flow means all areas will have a shot of seeing highs well into the 60s with some more readings near 70 ISW to OSH.

Long Term...Tuesday Night Through Sunday

An upper level disturbance moving with the zonal flow will bring a chance of showers and a few thunderstorms Tuesday night. Latest trends is to slow the precipitation down and have trended this way with 3 hourly pop grids to reflect the slower arrival time of the rain. I may still be too quick with the precipitation as the 00z ECMWF doesn't get the precipitation here until 06z Wednesday.
Best forcing will be across northern Wisconsin with the shortwave energy. Of concern is the precipitation totals of the ECMWF are pretty skimpy across east-central Wisconsin, thus there is concern on the amount of coverage of precipitation across east-central and portions of northeast Wisconsin. The shortwave should exit the area late Tuesday night into early Wednesday morning. Kept a small pop just in case the timing if even slower on the next few model runs.

Will need to watch Wednesday for some fire weather concerns as mild temperatures and humidity readings plunge across northern Wisconsin. Humidity readings will be in the 30s percent, but could go a little bit lower over the next day or two. Winds are expected to be in the 10 to 20 mph range with gusts around 25 mph. On Wednesday into Thursday, a 500mb trough will begin to deepen across the Rockies into the central plains with ridging across the mid- Atlantic states. A warm front is going to set up well south of the area, from central Iowa into northern Illinois by 12z Thursday. This is a tad bit further south than yesterday. Based on the ECMWF, central and east-central Wisconsin will be on the northern edge of the precipitation shield. By Thursday afternoon, the ECMWF has the warm front pushing northward into southern Wisconsin, bringing showers and increasing chances for thunderstorms during the day. We will still be in the cool sector, thus there could be a trend for slightly cooler high temperatures in the coming days. There are some considerable differences between the GFS/ECMWF/Canadian on the track of the surface low and placement and timing of the heaviest QPF totals. There is plenty of time to sort out the details, but heavy rain may be a possibility Thursday and Thursday night. Model differences continue this weekend, thus hard to discern this far out what day would have the highest probability of rain, if any?

Temperatures will be seasonable for the most part, with Wednesday possibly the warmest day while cooler temperatures are possible over the weekend.

AVIATION
for 06Z TAF Issuance Issued at 1054 PM CDT Sun Apr 28 2024

A low pressure system will move slowly from Southern Minnesota to Upper Michigan by Monday evening. There will be scattered showers and isolated thunderstorms late tonight through midday Monday.

IFR ceilings are expected tonight through at least midday Monday, with some improvement in east central Wisconsin in the afternoon.
Visibility will fall to around one mile over much of the area overnight as a warm front lifts north. The visibility will improve Monday afternoon as a weak cold front moves through.

GRB WATCHES/WARNINGS/ADVISORIES
None.

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