Marine Weather and Tide Forecast for Alpena, MI

SHORT TERM /THROUGH TONIGHT/
Issued at 252 AM EDT Tue May 20 2025

Surface high pressure continues overall quiet weather driven by midlevel riding currently over the Upper Midwest. 500mb pattern is a trough over the northeastern CONUS, ridging moving across the Great Lakes, followed by another upstream trough depicting a poorly dawn omega. Not a whole lot of active weather tonight as subsidence leads to subsequent clear skies and chilly overnight lows. Current light winds from the north along with radiational cooling processes will lead to quickly dropping temperatures across the CWA 00Z sounding along with ASOS data depicts dew points in the low 20s and 30s. This in theory would drop interior northern lower into widespread frost/hard freeze territory, but overnight lows are expected to remain in the mid to upper 30s thanks to the upstream trough advecting surface low pressure into Iowa and increasing pressure gradient force winds.

Conditions today will look pretty similar to Monday as another day of surface high pressure continues relatively quiet conditions before closed low pressure moves eastward. PGF winds driven by warm air advection will continue to keep breezy westerly winds across northern Michigan with afternoon gusts as high as 25 kts. Cloud cover will remain pretty clear for most parts during the day but is expected to increase in the afternoon/evening hours along with returning chances of precip Tuesday night. Some showers may be possible after 00z Wednesday (7pm Tues) for southwest parts of the CWA Biggest struggle for rain Tuesday night will be rain trying to overcome top-down saturation. Radar will definitely pick up showers spreading, but liquid amounts reaching the surface will likely be less than a tenth and only be enough the wet surfaces along counties south and west of Traverse Bay.

LONG TERM /WEDNESDAY THROUGH MONDAY/
Issued at 252 AM EDT Tue May 20 2025

Midlevel troughing with closed low pressure will be centered over the Dakotas at the start of the long term. Troughing quickly travels across the Ohio Valley Wednesday then circulates around the Great Lakes region for the remainder of the week. Subtropical jet over the mid Atlantic will cut off efficient moisture advection into the region... thus keeping precipitation pretty light and disorganized.
Best chance of rain will be Wednesday and Thursday depending on where you live across the CWA The southern tier of counties will likely see less than a tenth of an in of QPF as the low pressure moves eastward. Troughing then sets up over Great Lakes region and delivers wrap around moisture to Lake Huron... favoring areas east of I-75. Otherwise the majority of the CWA remains cloudy and cooler than normal for late May.

Troughing finally begins to move northeast and returns subsequent high pressure to the Great Lake around the Saturday/Sunday timeframe. Some lingering nuisance showers remain possible, but and overall drying pattern is supported for Memorial Day weekend.
Temperatures will slightly climb into the 60s and maybe even low 70s for a few areas, which is just in time for the holiday weekend to actually feel like summer.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
Issued at 616 AM EDT Tue May 20 2025

VFR conditions expected through the period. Skies becoming SCT- BKN250 through today for most areas. Winds 060-090 10-15G25KTs much of the day today. Chance for -SHRA/-RA late in the TAF cycle for KMBL and KTVC with CIGs dropping to OVC050 for these locations.

APX WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...Small Craft Advisory until midnight EDT tonight for LHZ345.
Small Craft Advisory until midnight EDT tonight for LHZ349.
Small Craft Advisory until midnight EDT tonight for LMZ323-341- 342-344>346.