095
FXUS63 KMQT 311732
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
132 PM EDT SUN AUG 31 2025
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE (20 TO 40%
CHANCE) THIS AND LABOR DAY AFTERNOONS, MAINLY OVER THE WEST
HALF.
- A COLD FRONT WILL MOVE THROUGH THE REGION TUESDAY NIGHT AND
WEDNESDAY. THIS WILL BRING WIDESPREAD RAIN TO UPPER MICHIGAN
AND STRONG WINDS TO THE KEWEENAW.
- A COOL AIRMASS WILL BUILD OVER THE UPPER GREAT LAKES LATE THIS
WEEK.
- THERE IS A 20-40% CHANCE FOR NORTHWEST GALES TUESDAY NIGHT
INTO WEDNESDAY, MAINLY WEST AND NORTH OF THE KEWEENAW
PENINSULA.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 132 PM EDT SUN AUG 31 2025
HIGH PRESSURE OVER THE AREA SUPPORTED A MOSTLY CLEAR MORNING. THIS
ALLOWED TEMPERATURES TO WARM INTO THE LOW TO MID 70S FOR MOST OF THE
REGION WITH LIGHT WINDS. DAYTIME HEATING IS RESULTING IN SOME
INSTABILITY; THIS AND A VERY WEAK WAVE ALOFT ARE SUPPORTING
SCATTERED CLOUDS OVER CENTRAL AND WESTERN UPPER MICHIGAN IN THE PAST
HOUR OR TWO AND MORE PERSISTENT BROKEN TO OVERCAST SKIES FAR EAST.
AS THE AFTERNOON PROGRESSES, A LAKE BREEZE OFF SUPERIOR MAY BE THE
FOCUS FOR ISOLATED OR SCATTERED SHOWER OR THUNDERSTORM ACTIVITY.
VERTICAL SHEAR IS VERY SMALL OR NONEXISTENT, SO ANYTHING THAT
DEVELOPS ISN'T EXPECTED TO BE STRONG OR SEVERE. INSTEAD, THESE WOULD
BE EXPECTED TO RIDE THE LAKE BREEZE BRIEFLY OR SLOWLY DIMINISH AS
THEY MOVE OFF THE BOUNDARY.
ANY CONVECTIVE ACTIVITY SHOULD WANE WITH THE SETTING SUN.
AFTERWARDS, A MIX OF CLEAR CONDITIONS AND MID-HIGH CLOUDS ARE MOSTLY
EXPECTED OVERNIGHT. WE SHOULD COOL TO NEAR 50 INTERIOR AND 50S OR
NEAR 60 LAKESIDE. IF RAIN DOES OCCUR, COOLING MAY SUPPORT POCKETS OF
FOG WHERE IT RAINED. MONDAY, SIMILAR CONDITIONS ARE EXPECTED, WITH
THE POTENTIAL FOR AFTERNOON SHOWERS AND STORMS ACROSS THE WEST WITH
DAYTIME TEMPERATURES CLIMBING INTO THE 70S.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 337 AM EDT SUN AUG 31 2025
AN EXPANSIVE MID-UPPER LEVEL RIDGE CONTINUES TO STRETCH ACROSS THE
UPPER GREAT LAKES LABOR DAY TO AT LEAST TUESDAY. WITH 1020-1025MB
RIDGING OVER THE REGION THANKS TO A SURFACE HIGH SLOWLY STRETCHING
EASTWARD THROUGH THE GREAT LAKES INTO NEW ENGLAND, MOSTLY DRY
CONDITIONS ARE EXPECTED IN UPPER MICHIGAN. THE EXCEPTION TO THIS IS
LABOR DAY AFTERNOON, HOWEVER, AS A WEAK RETROGRADING VORT MAX
ALONGSIDE DAYTIME INSTABILITY GROWS TO ~1000J/KG, POTENTIALLY
YIELDING ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ALONG THE
LAKE BREEZE BOUNDARIES OF NORTH-CENTRAL AND WESTERN UPPER MICHIGAN.
DEEP LAYER SHEAR OVERALL LOOKS TO BE WEAK, SO STRONG OR SEVERE
STORMS ARE NOT ANTICIPATED SHOULD CONVECTION DEVELOP. STEADY 850MB
TEMPS OF 11-13C LABOR DAY AND TUESDAY WILL PRODUCE TEMPERATURES IN
THE MID TO UPPER 70S FOR MOST OF THE REGION. ALTHOUGH INCREASING
CLOUDS ON TUESDAY MAY RESULT IN HIGHS ONLY PEAKING IN THE LOW 70S IN
SOME LOCATIONS ACROSS THE WEST HALF. OVERNIGHT LOWS MONDAY NIGHT
WILL FALL INTO THE MID TO UPPER 50S NEAR THE LAKESHORES AND IN THE
KEWEENAW AND THEN TO NEAR 50F AWAY FROM THE LAKESHORES.
A PRONOUNCED UPPER LEVEL LOW IS EXPECTED TO DIVE SOUTHEAST THROUGH
MANITOBA AND ONTARIO LATE TUESDAY AND WEDNESDAY. 0Z AND 12Z
DETERMINISTIC GUIDANCE SUGGESTS THIS FEATURE WILL PARK OVER THE
UPPER GREAT LAKES WEDNESDAY NIGHT INTO THURSDAY AS IT TAKES ON A
NEGATIVE TILT, THEN LIFT NORTH AND EAST INTO HUDSON BAY THROUGH
FRIDAY NIGHT. THERE'S MORE AMBIGUITY IN THE SURFACE FEATURES, BUT
THE OVERALL CONSENSUS IS A DEEPENING LOW WILL DEVELOP ALONG A
DESCENDING COLD FRONT LATE TUESDAY. THE LOW, OR A SECONDARY SURFACE
LOW, WILL MOVE THROUGH OR NEAR UPPER MICHIGAN/LAKE SUPERIOR
WEDNESDAY OR WEDNESDAY NIGHT BEFORE BEING PUSHED NORTHWARD WEDNESDAY
NIGHT, POTENTIALLY RETROGRADING THURSDAY OVER NORTHERN ONTARIO, THEN
FINALLY EXITING NORTHEAST INTO HUDSON BAY FRIDAY NIGHT. DESPITE
BEING 4+ DAYS OUT, THIS GENERAL EVOLUTION IS HANDLED WELL BY THE
DETERMINISTIC AND ENSEMBLE GUIDANCE SUITES. THIS INCLUDES THE COLD
FRONT MOVING THROUGH UPPER MICHIGAN WEDNESDAY, RESULTING IN A LARGE
SWATH OF PRECIP SPREADING ACROSS THE AREA AHEAD OF THE BOUNDARY, AND
THE STRONGER WIND SIGNAL FOR THE KEWEENAW, WHICH MAY RESULT IN 30-40
MPH WIND GUSTS WEDNESDAY. ADDITIONALLY, MODEL RUN TO RUN CONSISTENCY
INCLUDES A SURGE OF COOLER AIR FILLING IN BEHIND THE FRONT,
RESULTING IN BELOW NORMAL TEMPERATURES TO FINISH OFF THE WORK WEEK.
EXACTLY WHERE THE COLDEST AIR ENDS UP IS STILL A QUESTION, BUT THE
GENERAL IDEA IS FOR 850MB TEMPS TO FALL TO +1 TO -3C. THIS WILL
YIELD DAYTIME HIGHS IN THE 50S OR LOW 60S AND OVERNIGHT LOWS IN THE
40S BY THE LAKES AND 30S INTERIOR. SUSPECT FROST COULD BE A CONCERN
TOWARD THE LATTER HALF OF THE WEEK, ALTHOUGH THE COOLER TEMPS ALOFT,
CONTINUED CYCLONIC MID-LEVEL FLOW, POTENTIAL FOR A SECONDARY SURFACE
TROUGH, AND LAKE EFFECT/ENHANCED RAIN, MAY WORK AGAINST SIGNIFICANT
OVERNIGHT COOLING IN SOME LOCATIONS.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 132 PM EDT SUN AUG 31 2025
VFR CONDITIONS WILL PREVAIL IN THIS TAF PERIOD AT ALL SITES. A
SHOWER OR STORM MAY POP UP THIS AFTERNOON AND IMPACT KIWD, BUT
CONFIDENCE ISN'T HIGH ENOUGH TO WARRANT A LINE IN THE TAF.
MARINE
ISSUED AT 337 AM EDT SUN AUG 31 2025
HIGH PRESSURE RIDGING OVER THE REGION WILL, OVERALL, RESULT IN WINDS
BELOW 20KTS FOR A MAJORITY OF THE PERIOD THROUGH TUESDAY MORNING. BY
AFTERNOON ON TUESDAY, INCREASING PRESSURE GRADIENT WILL ALLOW FOR
INCREASING SOUTHWESTERLY WINDS ACROSS THE WESTERN AND NORTHERN
PORTIONS TO BUILD TO NEAR 20KTS. A COLD FRONT WILL MOVE MOVE THROUGH
THE REGION LATE TUESDAY/TUESDAY NIGHT INTO WEDNESDAY. BEHIND THE
FRONT, WINDS WILL QUICKLY BECOME NORTHWEST AND INCREASE AS COOLER
AIR BUILDS OVER LAKE SUPERIOR. GUIDANCE CONTINUES TO SUGGEST THE
POTENTIAL FOR GALES WEDNESDAY. LATEST ENSEMBLE GUIDANCE PACKAGES
VARY, BUT GENERALLY SUGGEST 20-40% CHANCE OF NNW OR NW GALES TUESDAY
NIGHT AND WEDNESDAY. HIGHEST PROBABILITIES ARE LOCATED WEST OF THE
KEWEENAW BETWEEN THE PENINSULA AND ISLE ROYALE AND LESSER AMOUNTS
NORTHEAST AND EAST OF THE KEWEENAW PENINSULA. NORTHWEST TO WESTERLY
FLOW WILL PERSIST OVER THE LAKE FOR THE REMAINDER OF THE WEEK,
SLOWLY FALLING BELOW 20KTS BY LATE FRIDAY.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...JTP
LONG TERM...JTP/TAP
AVIATION...JTP
MARINE...JTP/TAP
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