Marine Weather and Tide Forecast for Finlayson, MN

DISCUSSION
Issued at 323 PM CDT Mon May 12 2025

SHORT TERM (Today Through Tuesday Night):

Critical fire weather conditions are expected to continue this afternoon and early evening, with a Red Flag Warning in effect. Very dry conditions with relative humidity below 20% have been observed this afternoon as deep diurnal mixing has occurred. In addition to the dry conditions, strong southerly winds have been gusting up to 30 mph. Expect clear skies tonight with warm temperatures as WAA continues and high pressure persists.

Another day of critical to near-critical fire weather conditions are expected tomorrow as a moderately strong pressure gradient develops ahead of approaching low pressure. A Fire Weather Watch has been issued for much of the CWA, excluding Ashland, Iron, and Price Counties in WI. Those 3 counties will likely (60% chance) see winds remain at or below 10 mph tomorrow, limiting the concern for critical fire weather conditions. However, across the remainder of the CWA, an upgrade to a Red Flag Warning will likely be needed for tomorrow as min RH once again drops to 25% or lower and southerly to southeasterly winds increase. As winds begin to ease late Tuesday afternoon, a lake breeze moving inland will be possible. The inland extent of this lake breeze will be dependent on how fast southerly winds can ease, but the best timeframe will be around 1800-1900 CDT.

LONG TERM (Wednesday Through Next Monday Night):

Continued warmth on Wednesday with southerly flow ahead of low pressure across the Plains. However, moisture levels are expected to be on the rise with dewpoints in the 50s, which is expected to equate to afternoon minimum relative humidity levels in the 30 to 40 percent range for most areas. Widespread high temperatures in the 80s are once again favored across the Northland. Southeasterly winds will be strongest across northeast Minnesota, at 10 to 15 mph. Given fuels across the region, this will have to be monitored for one more day of fire weather concerns. Isolated to scattered rain showers and a few thunderstorms are expected Wednesday afternoon through sunset, especially across northwest Wisconsin and into the I-35 corridor with a couple impulses aloft in the weak flow. Severe weather is not expected.

On Thursday, the concern changes from fire weather to severe convection. A negatively tiled mid level trough is forecast to propagate into the upper Mississippi Valley Thursday afternoon, with an arc of buoyancy on the order of 1500-2000j/kg developing across northwest Wisconsin and into the I-35 corridor, and potentially into the Iron Range away from the influence of Lake Superior. This arc of buoyancy will be in association with a rapidly deepening surface low across central Minnesota, with a cold front intersecting an west- east warm front across Lake Superior, and then occluding into the interior portions of northeast Minnesota. Shear will be strong with a 70+ kt mid level jet above a 45kt low level jet. Veering will be most substantial in the low levels, especially across northwest Wisconsin between the warm and cold fronts, with shear rather unidirectional aloft. Given strong forcing and the depth of the negatively trough and surface low, convection is expected across most of the Northland Thursday afternoon and into the evening. AI probabilities align with the conceptual model of the setup for a severe threat across most of the area, with the greatest risk across northwest Wisconsin where buoyancy will be greatest. The usual uncertainty sources of mid level cloud cover and some capping are shown on the soundings. The primary threats at this time appear to be damaging winds with fast moving linear segments, followed by the tornadic threat across northwest Wisconsin where low level shear will be greatest with both supercellular and QLCS tornadic threats in play.

For Thursday night into Friday, wrap around precipitation will spread across the Northland as the deep low propagates northeast towards western Lake Superior and southwest Ontario. There is a non- trivial spread in the placement of the low Thursday into Friday across southern Ontario. Despite this, the story will be relatively the same of deformation zone and wrap around precipitation with increasing westerly winds Thursday night into Saturday. Some snow may mix in Friday night into Saturday morning across the Borderlands as 850mb temperatures fall below freezing.

Overall, very much needed rainfall is expected Thursday into Saturday. The most significant rainfall will be across the Brainerd Lakes area into Koochiching county with strong deformation zone banded rainfall to start off the event. Rainfall amounts in excess of 1 inch are most favored, a 40 to 60 percent chance, for these areas. Elsewhere across the Northland, rainfall totals will range from one half to three quarters of an inch, with locally higher pockets with stronger thunderstorms.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
Issued at 610 PM CDT Mon May 12 2025

VFR conditions and breezy south to southeasterly winds prevail the entire TAF period. The exception is for terminals in eastern St. Louis County and across the inland Arrowhead where wildfire smoke is bringing smoke and reductions in visibility to those locations. Smoke is forecast to linger at those areas tonight and possibly through tomorrow.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 323 PM CDT Mon May 12 2025

A Small Craft Advisory is in effect for the South Shore of Lake Superior until 7 pm tonight with strong northeast winds. The next hazardous weather event is expected to be on Thursday, which will bring in northeast wind gusts of 25-30 knots with waves building to 4 to 6 feet. As this system moves north on Friday, winds will shift to the southwest.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.

CLIMATE
Issued at 423 PM CDT Mon May 12 2025

Record High Temperatures: Forecast Current May 13: KINL: 88 87/1977

May 14: KINL: 87 89/1991

Record Warm Low Temperatures:

May 13: KDLH: 56 54/1991 KINL: 61 55/1987 KHIB: 52 52/1987 KASX: 57 58/1987

May 14: KINL: 61 58/1977 KBRD: 61 62/1998 KHIB: 54 54/1998

May 15: KINL: 59 60/1998

DLH WATCHES/WARNINGS/ADVISORIES
MN...Red Flag Warning until 9 PM CDT this evening for MNZ010>012- 018-019-025-026-033>038.
Fire Weather Watch from Tuesday morning through Tuesday evening for MNZ010>012-018-019-025-026-033>038.
WI...Red Flag Warning until 9 PM CDT this evening for WIZ001>004- 006>009.
Fire Weather Watch from Tuesday morning through Tuesday evening for WIZ001-002-006>008.
MARINE...Small Craft Advisory until 7 PM CDT this evening for LSZ121- 145>148.