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Marine Weather and Tide Forecast for Bay City, MI

July 21, 2024 2:28 AM EDT (06:28 UTC) Change Location
Sunrise 6:12 AM   Sunset 9:11 PM
Moonrise 8:56 PM   Moonset 4:59 AM 
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NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.

Marine Forecasts
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LHZ422 Inner Saginaw Bay Sw Of Point Au Gres To Bay Port Mi- 937 Pm Edt Sat Jul 20 2024

Rest of tonight - West winds 10 to 15 knots veering to the northwest after midnight, then diminishing to 5 to 10 knots early in the morning. Partly cloudy. Waves 2 feet or less.

Sunday - North winds 5 to 10 knots becoming northeast 10 to 15 knots early in the afternoon. Partly cloudy. Isolated showers and Thunderstorms in the afternoon. Waves 2 feet or less.

Sunday night - Northeast winds 10 to 15 knots diminishing to 5 to 10 knots after midnight. Partly cloudy. Isolated showers and Thunderstorms in the evening. Waves 2 feet or less.

Monday - Northeast winds 5 to 10 knots. Mostly Sunny. Waves 2 feet or less.
see lake huron open lake forecast for days 3 through 5.

No data

7 Day Forecast for Marine Location Near Bay City, MI
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Area Discussion for - Detroit/Pontiac, MI
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Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1139 PM EDT Sat Jul 20 2024


* Low coverage of showers or thunderstorms both Sunday and Monday afternoon.

* Greater chances for showers and thunderstorms middle of next week.


A weak cold front will drop into Se Mi from the north on Sunday. Low level moisture pooling along this boundary will be supportive of the development of a broken cu field 4-6k feet by Sun afternoon. Weak to moderate instability will develop Sunday afternoon within the moisture pooling along the front, primarily affecting locations from PTK northward. The overall weak forcing should keep convection changes late Sun afternoon to 30% or less. The probabilities for thunderstorms are highest at mbS and will warrant the introduction of a PROB30 group for late afternoon convection.

For DTW/D21 Convection...Isolated to possibly scattered thunderstorms are forecast late Sunday afternoon. The chances are across the northern portions of the airspace in closer proximity to a frontal boundary.


* Low in ceilings aob 5000 feet Sunday afternoon.

* Low in thunderstorms Sunday afternoon and evening.

Issued at 315 PM EDT Sat Jul 20 2024


Seasonably high amplitude flow regime will hold in place across North America into early next week before going through one more episode of amplification during the midweek prior to transitioning to a more progressive state by week's end.

The main feature of note with the next little impulse of height falls is the ribbon of concentrated moisture along the lower tropospheric front settling south across the Northern Great Lakes region today. The shearing deformation within the overall weak geopotential field will stall out across Central Lower Michigan Sunday and Monday. There will be adequate moisture pooling within this zone to support weakly capped modest instability generation (~1.5 kJ/kg MLCAPE) across the Saginaw Valley and Thumb on Sunday.
Furthermore, this is the region that possesses the greatest CAPE depth, thereby the best opportunity for convective initiation.
Furthermore, slightly unbalanced flow aloft in the entrance zone to tropopause level jet and near surface focus near lake-breeze features should support isolated convection during the middle and late afternoon. Coverage should remain meager given the capping layer and insufficient forcing to adiabatically erase. Quick pulse nature to the convection is expected given the lack of shear, or any flow in the column for that matter.

Only minor changes to the overall setup on Monday. Mainly the decaying deformation axis will be perturbed by the meandering upper circulation, currently over the Mid-Mississippi Valley, as it wanders into the Southern Great Lakes Region. Some weak flow imbalance aloft near the leading flank of the wave should be enough to instigate isolated to scattered convective development once again. The instability axis will rotate cyclonically and recenter over interior portions of the Lower Peninsula. Greatest CAPE depth looks to exist across the Saginaw Valley south to along and west of the glacial ridge. Again, lack of shear and flow will support garden variety smaller scale pulse convection. More of the same can be expected Tuesday with continued general weak geopotential troughing and adequate diurnal destabilization.

A more substantial deep tropospheric wave will pivot around the Eastern North American trough into the Great Lakes region on Wednesday. Certainly better over all forcing and better instability density in the mid-levels to support a more vigorous convective response. The flow remains rather weak; however, deep layer shear does increase sufficiently to support organized convection.


Influence of surface high pressure wanes through the reminder of the day as said high weakens. A weak cold front gradually sags through the region this weekend into the beginning of next week offering scattered shower and thunderstorm chances focused in the afternoon- evening each day. Winds shift to N-NE behind this front though speeds remain light at or below 10kts. Wider spread shower/storm chances don't arrive until midweek when a trough dives out of Canada into the Great Lakes.

Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

Weather Reporting Stations
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Stations Dist Age Wind AirWater WavesinHgDewPt
SBLM4 - Saginaw Bay Light #1, MI 18 mi88 minNW 8G8.9 74°F 30.05
45163 32 mi48 minNNW 5.8G7.8 72°F 1 ft30.09
GSLM4 - Gravelly Shoals Light MI 35 mi48 minNW 8.9G9.9 73°F 30.07

Wind History for Harbor Beach, MI
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Detroit, MI,

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