Marine Weather and Tide Forecast for Sebewaing, MI

SHORT TERM /THROUGH TONIGHT/
Issued at 253 AM EDT Fri Oct 11 2024

Pattern Synopsis/Forecast: Low amplitude mid-level ridging continues to fold across the western Great Lakes early this morning in advance of upstream troughing set to cross the area later today. Attendant surface low pressure expected to shift over Hudson Bay with a cold front crossing northwest to southeast across the forecast area this afternoon and early evening. Cold/dry advection behind this boundary with higher surface pressures oozing back into the region tonight.

Forecast Details: High clouds continue to gradually increase across northern Michigan at this early hour, likely resulting in some filtered sunshine after sunrise this morning. Increasingly gusty southwest winds will aid to boost high temperatures some 15-20 degrees above mid-October normals -- spanning the 70s area-wide with even some 80 degree readings attainable across northeast lower.
Those gusty winds and warm temperatures will combine with near- critical relative humidity values and very dry fuels from a lack of recent rainfall -- all enough to warrant a Red Flag Warning across northern lower today.

The wrench thrown in arrives this afternoon in association with that cold front arriving from the northwest. Front is expected to clear the eastern U.P. and far northwest lower by mid-late afternoon and through the remainder of the forecast area by mid-evening. While a lack of moisture in anticipated (hence the dry RHs mentioned above), isolated to scattered showers may develop ahead of/along this boundary. Suppose if this activity does manage to develop, that a few thunderstorms can't be ruled out as well given elevated instability progged as high as ~750 J/kg. Modest deep layer shear in excess of 40 kts and steep mid-level lapse rates could, in theory, contribute to a stronger storm, but a stable boundary layer should prevent higher end wind gust potential. Best guess at timing based on latest trends suggests those low end shower/storm chances arrive across northwest lower between 18-21z and over northeast lower between 21-01z. All this said, the expectation is that the vast majority of the forecast area remains rain-free this afternoon amidst more numerous clouds.

Cold/dry advection to follow area-wide as winds turn out of the northwest post-fropa. Winds eventually diminish during the second half of the night ahead with lows expected to fall into the mid-30s to mid-40s.



LONG TERM /SATURDAY THROUGH THURSDAY/
Issued at 253 AM EDT Fri Oct 11 2024

Pattern Synopsis and Forecast:

Current midlevel pattern over the CONUS consists of longwave ridging spanned across the majority of the U.S with troughing over the Northern Pacific. Any active weather will be generated from a few shortwaves progressing through the Great Lakes region next week beginning early Sunday.

The first shortwave will begin to lower heights this Sunday along with returning shower and storms chances. Cold air building behind the frontal passage will generate some pretty chilly overnight lows along with generating some potential lake enhanced showers into early Tuesday. Midlevel heights begin to build towards the end of the long term, allowing for temperatures to warm at or above average for mid October along with building surface high pressure later next week.

Primary forecast concerns/key messages:

Shower and storm chances return Sunday: Shortwave troughing currently over the Arctic Circle will settle into the Great Lakes region this Sunday. Surface low pressure will develop over southern Hudson Bay along with directly over the CWA, draping a frontal boundary to provide enough lift for scattered showers and storms to persist. While SPC has no severe risk next week, moderate amounts of elevated shear advecting into the region will keep thunderstorm chances in the forecast along with a general quarter inch of precipitation expected.

Cold overnight temperatures next week along with a few chances of snow: Cold, polar air will settle into the CWA as northern branch midlevel flow will drop into the Ohio Vally Sunday night through Tuesday. Northerly flow combined with a Delta T value of over 20 degrees will continue lake enhanced showers into Tuesday as troughing continues to pivot through the region.
Showers will continue to be scattered and mainly impacting areas that experience northerly flow, but cold overnight temperatures and with 850mb temperatures well below freezing might introduce the season's first batch of mixed precipitation to interior northern Michigan. Guidance tends towards light amounts of QPF this Monday and Tuesday due to such dry air aloft, but pattern recognition leads to suggest occasional showers along with overnight snowflakes may mix into interior northern lower/eastern upper for the first half of next week.



AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
Issued at 1145 PM EDT Thu Oct 10 2024

Large area of strong high pressure will drop SE out of the Great Lakes and into the Appalachians overnight...as a moisture- starved cold front swings out of Central Canada and into Western Lake Superior by daybreak Friday. This cold front will drive thru Northern Michigan on Friday...resulting in some increase in cloud cover and only small chances of showers during the afternoon/early evening. Conditions will remain VFR for the next 24 hours. Southerly surface winds under 10 kts overnight will become SE at around 10 kts Friday morning...and will then shift to the W/NW and increase to 15 to 25 kts with some higher gusts Friday afternoon/evening behind the cold front.

APX WATCHES/WARNINGS/ADVISORIES
MI...Red Flag Warning from 8 AM this morning to 8 PM EDT this evening for MIZ016>018-020>036-041-042-099.
MARINE...Small Craft Advisory from 6 AM this morning to 6 AM EDT Saturday for LHZ345>349.
Small Craft Advisory from 8 AM this morning to 2 AM EDT Saturday for LMZ323-346.
Small Craft Advisory until 2 AM EDT Saturday for LMZ341-342- 344-345.
Small Craft Advisory from 11 AM this morning to 6 AM EDT Saturday for LSZ321-322.