Marine Weather and Tide Forecast for Copper City, MI

SHORT TERM /THROUGH THIS AFTERNOON/
Issued at 251 AM EDT Wed Apr 30 2025

Expect a brief period of quiet and dry weather for our Wednesday with high pressure currently analyzed directly over the UP.
Northerly flow off of Superior in the north-central and eastern UP is keeping in some low stratus early this morning. Where skies remain cloudy, temperatures are only expected to fall back as far as the upper 20s to around 30F. Elsewhere (mainly the south-central and western UP) expect lows a couple degrees cooler, generally in the mid and upper 20s.

As we head into the daytime hours, the surface high begins to shift eastward. Southerly winds on the backside of the ridge will bring in much warmer temperatures than yesterday, with highs in the central and western UP ranging well into the 50s and low 60s. The eastern UP should stay cooler with flow off of Lake Michigan; there, expect highs to range in the 40s. As daytime mixing kicks off, soundings support a good drop in dewpoints this afternoon, as low as the upper 20s in the western UP and the low 20s in the eastern UP. This would support minimum RH as low as 30%, or potentially lower in the eastern UP, while at the same time southerly wind gusts pick up to around 20mph throughout the western half of the UP. However, fire weather concerns will be limited somewhat by recent widespread rainfall and relatively cool temperatures. Meanwhile, low cloud cover should lift as winds shift southerly, but expect high clouds to begin to work in during the afternoon in advance of a shortwave currently analyzed over the Southern Plains and another over the Canadian Prairies. These heads towards the Great Lakes Thursday while phasing, eventually bringing us our next chances for precipitation. More on that below.

LONG TERM /TONIGHT THROUGH TUESDAY/
Issued at 253 AM EDT Wed Apr 30 2025

Upper air pattern consists of a 500 mb trough with two branches over the plains 00z Thu. Northern branch has a shortwave in the northern plains and the southern branch has a shortwave over the southern plains 00z Thu. Both shortwaves affect the upper Great Lakes and combine and make a deeper trough over the area 00z Fri which moves into the lower Great Lakes by 12z Sat. Appears area will now be split between the two shortwaves with the southern one affecting the southern and eastern cwa and the northern one affecting the north and west. Previous forecasts looked like widespread rainfall would be possible, but with easterly low level flow, dry air will cut into the amounts of qpf a bit and this is the one change made to the forecast was to lower pops a bit.

In the extended, GFS and ECMWF 500 mb trough on the west coast, a ridge over the Rockies and a trough over the eastern U.S. and lower Great Lakes 12z Sat. By 12z Sun, a closed low is in the desert sw with troughing over the eastern U.S. 12z Sun with a ridge over the plains. The closed low moves into the Rockies 12z Mon and Tue with a shortwave over the northern plains 12z Tue. Ridging then moves into the Mississippi Valley 12z Wed. Temperatures stay above normal for this forecast period.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
Issued at 718 AM EDT Wed Apr 30 2025

Lingering low level cloud cover and MVFR ceilings at KSAW clears out by mid-morning, with VFR expected through the rest of the forecast period. Meanwhile, VFR prevails at IWD and CMX. Winds at KIWD/KSAW and possibly KCMX should also gust near 20kts during the daytime hours.

MARINE
Issued at 253 AM EDT Wed Apr 30 2025

Winds veer to the S/SE this afternoon as low pressure skirts across the MS River Valley and Northern Ontario, briefly tightening the pressure gradient across the region. Gusts will increase to 15-25 kts in the east and central lake and lessen below 20 kts Thursday.
Winds back to the N along a passing cold front Friday morning, increasing gusts back around 25 knots before tapering down into Saturday, where mostly light winds are expected this weekend.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.