Area Forecast Discussion

KEY MESSAGES

-Rain coverage generally diminishing into the afternoon with increasingly humid conditions. Residual shower development possible this afternoon across NW lower into far NE lower.

-Breezy to windy conditions this morning will slowly taper through the afternoon.

-Largely dry Wednesday through Friday with potential for another round of appreciable rainfall this upcoming weekend.

DISCUSSION

Issued at 241 AM EDT Tue Sep 15 2026

Pattern / Forecast Synopsis:

Strong corridor of isentropic lift being drawn into the region at this late hour as northern Michigan finds itself sandwiched between a mature 993mb surface low in Manitoba and departing strong 1026mb surface high currently making a run at the St. Lawrence River Valley / northern New England. Result is the complete overwhelming of the dry layer from Monday as deep moisture is drawn into the region amid an active 40kt low level jet nosing into the region, with copious lift / f-gen aloft providing more than enough support for rain showers to continue through the morning hours across the region once the associated surface warm front passes through... which will in turn lead to quite the humid afternoon across the region. In addition, pressure gradient most pinched overhead this morning will likely lead to quite a wind-driven rain for the most part... with some gusts pushing 40mph on the lakeshores and the highest of interior terrain, generally 25-35mph elsewhere. Once the warm front clears, winds should be on a downward trend as the pressure gradient slackens, but will still be a touch breezy through sunset.

Decaying precipitation shield looks to really keep cloud cover intact through the day, and surface temperatures likely struggle to break 70 across the Au Sable River Valley where current trends indicate that clouds / showers should linger longest. Elsewhere, temps spike into the 73-77 range as peeks of sun filter through and the warm nose moves firmly overhead, and dewpoints spike well into the 60s across the board. As such, this may be just enough for residual shower / thunder development in the afternoon as the surface cold front passes through northern Michigan. These should be on a localized scale and quite transient when considering the flow, but with the zenith of moisture concentration overhead, an isolated downpour is possible... primarily favoring spots along and NORTH of a Cadillac to Alpena line. Current trends do not support enough instability to drum up additional shower activity in eastern upper this afternoon.

The cold front will surge through in the evening, flipping winds more northwest, and commencing the intrusion of cooler and drier air as surface high pressure builds by Wednesday. Surface cold front associated with the ongoing system looks to turn stationary over the lower Great Lakes west into the Corn Belt (just north of an impressive late summer thermal ridge over the southeast CONUS), which should serve as the focus for additional low level jet driven rain / storms through midweek, likely keeping us dry through the rest of the week (aside from an isolated shower chance along / south of M-55 tonight, but guidance is trending quite bearish to this idea... front should be way too far south to support this anyways). As such, tentative thoughts at this juncture are that we hold dry and seasonable through Friday with highs in the 65-75 range and lows in the 40-55 range.

Looking at next weekend, long term guidance is warming up to the idea of another potent Pacific borne, southern stream wave ejecting into the Plains... coupled with another deep surge in moisture to boot. Still a bit early to make the call, but this pattern has basically started holding up a sign that says "HEAVY RAIN: PASS THROUGH HERE" with a giant, neon green arrow pointing at the Corn Belt into the entirety of the Great Lakes. Will have to see how amplified this wave is, as a far enough northward surge in moisture could certainly put us in play for another round of efficient to even heavy rainfall this upcoming weekend.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 1153 PM EDT Mon Sep 14 2026

Worsening conditions as rain moves in overnight. Heavy rain at times at all sites. Best chance of thunder MBL and perhaps TVC. MVFR to IFR cigs/vsbys overnight. On Tuesday, rain gradually departs. IFR cigs linger thru midday at CIU, and for a few hours at PLN. MVFR cigs in the morning elsewhere, becoming VFR in the afternoon. Gusty southerly winds increase tonight, becoming sw Tue afternoon.

APX WATCHES / WARNINGS / ADVISORIES

MI...Beach Hazards Statement from 6 AM EDT this morning through this evening for MIZ016-018-020-024-025-030-031-036-042- 088-095-096-098-099. MARINE...Gale Warning until 5 PM EDT this afternoon for LHZ345. Gale Warning until 5 PM EDT this afternoon for LHZ346>349. Gale Warning until 5 PM EDT this afternoon for LMZ323-341-342- 344>346. Gale Warning until 11 AM EDT this morning for LSZ321. Small Craft Advisory until 8 PM EDT this evening for LSZ322.