697
FXUS63 KMQT 031118
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
718 AM EDT SAT MAY 3 2025
KEY MESSAGES
- WARMER AND DRIER THAN NORMAL PERIOD AHEAD. LIMITED FIRE WEATHER
CONCERNS AS RHS FALL TO THE 30 PERCENT RANGE ON CLEAR SKY DAYS,
THOUGH GENERALLY LIGHT WINDS AND MOIST FUELS LIMIT THE FIRE WEATHER
POTENTIAL.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 213 AM EDT SAT MAY 3 2025
ELONGATED TROUGH STRETCHING FROM HUDSON BAY SOUTHWARD TO NEAR THE
TEXAS/OKLAHOMA BORDER WITH MULTIPLE SHORTWAVES EMBEDDED WITHIN ARE
CURRENTLY ANALYZED USING GOES WATER VAPOR CHANNELS AND LATEST RAP.
AT THE SURFACE, HIGH PRESSURE IS BEGINNING TO STRETCH INTO THE UPPER
GREAT LAKES AHEAD OF STOUT MID-UPPER LEVEL RIDGING BUILDING UP THE
ROCKIES. THE INCREASING SUBSIDENCE AND DRY MID-LEVEL AIRMASS OVER
THE REGION HAS TRAPPED MOISTURE AT THE LOW LEVELS, WHICH IS
SUPPORTING POCKETS OF FOG IN THE KEWEENAW/LOWER SPINE THANKS TO SOME
COOLING. OTHERWISE, OUTGOING SHORTWAVE AND LINGERING LOW TO MID-
LEVEL MOISTURE HAS SUPPORTED WIDESPREAD OVERCAST SKIES, PER GOES IR
IMAGERY. THE BLANKET OVERHEAD HAS LIMITED COOLING; DESPITE THIS
THOUGH, WIDESPREAD 30S HAVE BEEN OBSERVED WITH SOME SITES ACROSS THE
SOUTH-CENTRAL STILL OBSERVING NEAR 40F AT THE TIME OF THIS
PUBLISHING.
TODAY, DRY CONDITIONS AND LIGHT WINDS WILL PREVAIL THANKS TO SURFACE
RIDGE AXIS SHIFTING EASTWARD THROUGH UPPER MICHIGAN. THIS WILL HELP
SKIES CLEAR FROM WEST THE EAST AND THE EVENTUAL DEVELOPMENT OF A
LAKE BREEZES OFF THE GREAT LAKES. DAYTIME MIXING IN THE WEST UNDER
THE CLEAR SKIES AND TEMPERATURES WARMING INTO THE LOW 60S MAY
SUPPORT RH VALUES DIPPING INTO THE LOWER 30S TO UPPER 20S.
ELSEWHERE, SLIGHTLY COOLER CONDITIONS IN THE 50S SHOULD SUPPORT MORE
MOIST CONDITIONS, WITH MINIMUM RH VALUES IN THE 40S AND 50S INTERIOR
AND 60S BY THE LAKESHORES.
LONG TERM /TONIGHT THROUGH FRIDAY/
ISSUED AT 348 AM EDT SAT MAY 3 2025
TONIGHT, THE CONUS 500MB PATTERN MUCH RESEMBLES AN OMEGA BLOCK, WITH
A DIGGING TROUGH CENTERED ON THE COAST OF CALIFORNIA, RIDGING OVER
THE HIGH PLAINS, AND A CUTOFF LOW OVER THE MIDDLE MISSISSIPPI
VALLEY. THE BLOCK IS NOT AS STUBBORN AS TYPICAL OMEGA BLOCKS, AS THE
FLOW OVER THE WEST COAST SPLITS, WITH THE SOUTHERN STREAM BECOMING A
FOUR CORNERS CUTOFF LOW WHILE THE NORTHERN STREAM TROUGH KICKS THE
PLAINS RIDGING OVER THE UPPER GREAT LAKES BY EARLY MONDAY MORNING,
ALLOWING THE WAVE PATTERN TO PROGRESS. THE AFOREMENTIONED NORTHERN
STREAM TROUGH PUSHES OVER NORTHERN ONTARIO BY MIDWEEK, AND WHILE THE
SURFACE FEATURES AS A RESULT ARE NOT PARTICULARLY IMPRESSIVE FOR
PRECIPITATION PURPOSES, IT WILL BE THE WINDIEST PERIOD OF THE
FORECAST. HEIGHT RISES IN THE WAKE OF THE TROUGH WILL REINTRODUCE
HIGH SURFACE PRESSURE TO THE REGION FOR THE LATEWEEK PERIOD INTO
NEXT WEEKEND.
BEGINNING TONIGHT, A WEAK CLIPPER LOW OF AROUND 1008-1010MB WILL
DISSIPATE OVER NORTHWESTERN ONTARIO AND WESTERN LAKE SUPERIOR IN THE
FACE OF LINGERING 1018 MB HIGH PRESSURE OVER THE UP. WHILE THIS LOW
POSES NO PRECIPITATION THREAT, THIS WILL BRIEFLY RAMP UP
NORTHEASTERLY WINDS OVER WESTERN LAKE SUPERIOR, PARTICULARLY TO THE
WEST AND SOUTHWEST OF ISLE ROYALE WHERE WIND FUNNELING CAN
OCCUR. SLIGHTLY ENHANCED SOUTHERLY FLOW OVER THE WEST HALF UP
WILL CREATE SOME DOWNSLOPING FLOW THAT WILL KEEP LOW
TEMPERATURES AROUND 40 FROM IRONWOOD TO ABOUT ONTONAGON AND ALSO
FROM BARAGA/L'ANSE TO MARQUETTE DESPITE CLEAR SKIES THAT WOULD
OTHERWISE SUPPORT EFFICIENT RADIATIONAL COOLING. OTHERWISE,
LOWS IN THE MID 30S ARE EXPECTED.
SUNDAY, WITH THE LOW PRESSURE DISSIPATED, A REINFORCING SURFACE HIGH
CAN SWING INTO NORTHERN ONTARIO UNRESTRICTED FROM NORTHERN MANITOBA.
CONCERN IN THE FORECAST YESTERDAY WAS WITH A TIGHTENING PRESSURE
GRADIENT BETWEEN THAT HIGH AND THE SURFACE LOW ASSOCIATED WITH
UPSTREAM TROUGHING. HOWEVER, SINCE THEN, MODEL TRENDS HAVE KEPT THAT
LOW FURTHER AWAY FROM THE GREAT LAKES, SO THE GRADIENT HAS SLACKENED
AND THUS WINDS ARE EXPECTED TO BE LOWER. WHILE THE MAGNITUDE OF
WINDS HAS FALLEN, CAMS DO SHOW THAT A LAKE BREEZE IS EXPECTED, WHICH
COULD CAUSE SOME WIND DIRECTION PREDICTABILITY ISSUES. THE RH
FORECAST HAS TRENDED UPWARDS, AS EVEN CONSIDERING THE NBM10TH
PERCENTILE TDS ONLY BRINGS RHS TO THE MID-30S PERCENT RANGE. STILL,
SOME ATTENTION SHOULD BE PAID TO THIS ASPECT OF THE FORECAST, AS IF
RHS FALL SIGNIFICANTLY TODAY, IT COULD INSPIRE A MORE AGGRESSIVE RH
FORECAST FOR THE TOMORROW PERIOD. FOR NOW, ONLY "LIMITED" FIRE
WEATHER CONCERNS ARE FORECAST, PARTICULARLY FOR THE INTERIOR WEST
AND INTERIOR FAR EAST AWAY FROM THE LAKE BREEZE'S COOLING EFFECTS.
MONDAY STILL KEEPS HIGH PRESSURE INFLUENCING THE REGION FOR THE MOST
PART, BUT SOME WOBBLE IN THE SURFACE LOW ASSOCIATED WITH THE EASTERN
CONUS CUTOFF LOW DOES BRING ABOUT 15% CHANCES OF LIGHT PRECIPITATION
TO THE EASTERN HALF OF THE UP. EVEN IF NO PRECIPITATION FALLS, THE
ADDITIONAL MOISTURE ALOFT WILL INTRODUCE SOME CLOUD COVER WHICH WILL
KEEP RHS FROM FALLING AS MUCH. NBM WINDS OF AROUND 5 MPH WOULD ALSO
SUGGEST ANOTHER LAKE BREEZE DAY, ESPECIALLY AS HIGHS SOAR TO NEAR 70
FOR THE INTERIOR UP.
UNCERTAINTY BEGINS TO GROW IN THE FORECAST GOING FORWARD FROM ABOUT
TUESDAY AS THE ENSEMBLES STRUGGLE TO AGREE ON EXACTLY HOW THE LARGE
CUTOFF LOWS WILL INTERACT. FOR NOW, EXPECTING ROUGHLY 15-30% CHANCES
THAT THE SURFACE TROUGH ASSOCIATED WITH THE NORTHERN STREAM
TROUGHING WILL BRING LIGHT PRECIPITATION TO THE LATE-TUESDAY/EARLY-
WEDNESDAY TIME FRAME. WEDNESDAY DOES LOOK TO BE THE WINDIEST DAY OF
THIS FORECAST PERIOD AS STOUT 1030S MB HIGH PRESSURE FILLS IN BEHIND
THE SURFACE TROUGH, TIGHTENING THE PRESSURE GRADIENT. EURO ENSEMBLE
MEAN GUSTS WEDNESDAY ARE AROUND 25 MPH WITH AROUND 20% CHANCES OF
GALES ON LAKE SUPERIOR. THE ROBUST NORTHERLY FLOW WILL ALSO MAKE IT
THE COOLEST DAY OF THE PERIOD, ESPECIALLY NEAR LAKE SUPERIOR WHERE
TEMPERATURES WILL STRUGGLE TO BREAK OUT OF THE MID-40S, THOUGH THE
INTERIOR WEST COULD STILL APPROACH 60. ABOVE AVERAGE TEMPERATURES,
LIGHT WINDS, AND CLEAR SKIES RETURN TO THE FORECAST LATE IN THE WEEK
INTO THE WEEKEND AS HIGH PRESSURE DOMINATES.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 718 AM EDT SAT MAY 3 2025
MVFR CEILINGS AT KCMX/KSAW THIS MORNING WILL IMPROVE TO VFR BY
AFTERNOON, THEN PERSIST OVERNIGHT. KSAW MAY SEE VISIBILITY
REDUCTIONS LATE TONIGHT; HOWEVER, HOW LOW IS UNCERTAIN. KIWD WILL
PREVAIL VFR THROUGH THE PERIOD. LIGHT WINDS ARE EXPECTED THROUGH THE
PERIOD.
MARINE
ISSUED AT 348 AM EDT SAT MAY 3 2025
UNDER A SURFACE HIGH PRESSURE, WINDS WILL BE GENERALLY 20 KT OR LESS
THIS MORNING. THIS AFTERNOON, AN APPROACHING WEAK CLIPPER LOW OVER
NORTHWEST ONTARIO WILL BRING 20-25 KT SOUTHWEST GUSTS TO THE NORTH-
CENTRAL PORTIONS OF THE LAKE, PARTICULARLY AROUND ISLE ROYALE WHERE
FUNNELING OF WINDS CAN OCCUR. AS HIGH PRESSURE PREVAILS AND THE
LOW DISSIPATES, EXPECT LIGHT AND VARIABLE WINDS UNTIL TUESDAY
NIGHT, WHERE A COLD FRONT CROSSING THE LAKE WILL BRING NORTHERLY
GUSTS TO 25 KT WITH 20% CHANCES OF GALES FOR LATE TUESDAY NIGHT
THROUGH WEDNESDAY MORNING. THE RETURN OF HIGH PRESSURE BEHIND
THE FRONT WILL ALSO BRING THE RETURN OF MOSTLY LIGHT AND
VARIABLE WINDS TO THE LAKE.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...JTP
LONG TERM...GS
AVIATION...JTP
MARINE...GS
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