Marine Forecasts

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7 Day Forecast for Marine Location Near Reedsville, WI

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Area Discussion for - Green Bay, WI

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FXUS63 KGRB 241737 AFDGRB

Area Forecast Discussion National Weather Service Green Bay WI 1137 AM CST Wed Feb 24 2021

Updated aviation portion for 18Z TAF issuance

UPDATE. Issued at 538 AM CST Wed Feb 24 2021

There's just a little too much snow still left to come through to allow the advisory for N-C WI expire at 12Z. Will extend it a couple hours. That will also get through the morning commute. Will leave the 15Z expiration time in the far eastern part of the area unchanged.

SYNOPSIS. Issued at 409 AM CST Wed Feb 24 2021

Wintry precipitation ending this morning, but another round is likely Friday night into early Saturday. Temperatures remaining above seasonal normals through the weekend.

The upper pattern across North America will maintain low to moderate amplitude throughout the period. It is also likely to trend back toward at least a somewhat split nature. That's the pattern that dominated this winter up until the recent cold snap.

The lower amplitude/splitting flow will result in the forecast area primarily being affected by Pacific air masses that have downsloped the Rockies. That will keep temperatures AOA normal at least through the weekend. After that, there is considerable disagreement among the models on whether or not a quick-hitting but more significant shot of cold air will reach the area early next week. The pattern will be fairly energetic but moisture will be limited. So precipitation during the 7-day period will probably end up a little below normal.

SHORT TERM. Today . Tonight . and Thursday Issued at 409 AM CST Wed Feb 24 2021

The bulk of the effort spent on the short-term period this morning was in re-aligning the forecast details with the ongoing system. There is currently a bit of a lull in the precipitation across north-central Wisconsin as the primary area of isentropic lift was now off to the east. That was resulting in lighter snows along with FZDZ, as UP was noted on several obs in the past couple hours. FGen forcing along with QC forcing with the main mid-level shortwave were approaching from the west. The second area of forcing was accompanied by colder cloud tops and some higher returns spreading ESE on the KDLH radar. So a transition back to mainly snow is anticipated, with a couple hours of steadier snows before things begin to wind down for good. The advisory expires at 12Z across N-C WI. Will continue to monitor the situation, and may need to extend the advisory for a couple hours if it looks like snow will keep accumulating past 12Z. The 15Z expiration time in the east is probably okay.

Otherwise, temperatures tonight are a concern. Skycon guidance products are pretty aggressive in clearing things out late today. If that happens, there could be a period of clear skies and light winds right after sunset. Given the fresh snowcover, it's easy to see how temps across the north could crash to below zero. On the other hand, there is quite a bit of middle and high clouds out to the west on early morning satellite imagery. And those clouds will overspread the area at some point. So timing will be critical to the temperature forecast. Opted to trim mins 3-5 degrees across the north. Further reduction will probably be necessary if it becomes apparent the clouds won't arrive quickly enough.

The weak shortwave that was forecast to cross the area late tonight/early Thursday looks weaker than it did yesterday. Pulled back a little on PoPs, and now have just a trace event (flurries) for most areas.

LONG TERM. Thursday Night Through Tuesday Issued at 326 AM CST Wed Feb 24 2021

The arctic air will remain up in Canada through the weekend. Significant differences between the GFS (much colder) and the ECMWF for the brief arctic intrusion early next week.

For Thursday night and Friday, tranquil conditions are expected. Clear to partly cloudy skies should allow low temperatures to fall into the 10 to 20 degree range Thursday night. A few of the typical cold spots could drop into the single digits above zero. On Friday, high temperatures will rebound into the 30s thanks to the late February sunshine. Light snow is still looking pretty good Friday night. Some difference in the timing of the arrival of the snow. Most locations should see an inch or two. If the slower timing does come true, later shifts may need to add a chance of light snow for a few hours on Saturday morning.

The Saturday night and Sunday periods are more perplexing tonight. Based on the qpf output of the GFS and Canadian models, it appears an fgen band develops across the forecast. The GFS model has this feature developing late Saturday night into Sunday morning across central/north-central into northeast Wisconsin. The Canadian model has this feature across central into east- central Wisconsin during the day Sunday. The ECMWF has does not have this feature, thus extremely low confidence in adding a chance of precipitation for the Saturday night and Sunday period. Will see if this feature shows up over the next few days. Otherwise, the main story for early next week will be how cold it gets on Monday. At Green Bay, the GFS guidance has a high of 17F while the ECMWF guidance suggested 37F. Will let these differences work themselves out over the next several days. If the GFS is correct, the arctic blast will be nothing like the last one as 850mb temperatures rebound considerably by Tuesday.

AVIATION. for 18Z TAF Issuance Issued at 1135 AM CST Wed Feb 24 2021

Cloud cover was extensive for the beginning of the TAF period; however, clouds were beginning to mix out and becoming broken. This trend will continue over the next hour or two with most sites scattering out for the afternoon and evening. Otherwise, improving conditions will continue with high to mid clouds filtering back in overnight into Thursday.

GRB WATCHES/WARNINGS/ADVISORIES. NONE.

UPDATE . Skowronski SYNOPSIS . Skowronski SHORT TERM . Skowronski LONG TERM . Eckberg AVIATION . Cooley

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Weather Reporting Stations

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Stations	Dist	Age	Wind	Air Temp	Water Temp	Waves	Pressure	DewPt
GBWW3	25 mi	53 min	N 12 G 15	34°F			1009 hPa (+4.9)
KWNW3 - 9087069- Kewaunee, WI	33 mi	53 min	N 12 G 18	34°F			1008.2 hPa (+4.9)
SGNW3 - Sheboygan, WI	34 mi	53 min	NW 13 G 15	36°F

Wind History for Kewaunee MET, WI

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Airport Reports

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Airport	Dist	Age	Wind kt	Visibility	Sky/Weather	Temp	DewPt	Humidity	Pressure
Manitowoc, Manitowoc County Airport, WI	18 mi	57 min	NNW 15 G 21	10.00 mi	Light Rain	34°F	31°F	89%	1009.4 hPa
Green Bay, Austin Straubel International Airport, WI	22 mi	60 min	N 13	10.00 mi	Overcast	36°F	29°F	76%	1010.1 hPa

Link to 5 minute data for KMTW

Wind History from MTW (wind in knots)

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Tide / Current Tables for

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Tide / Current Tables for

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Weather Map

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