839
FXUS63 KMQT 220740
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
340 AM EDT TUE SEP 22 2026
KEY MESSAGES
- THIS MORNING, FROST AND FREEZE HEADLINES ARE IN EFFECT UNTIL 9 AM.
WIDESPREAD FROST IS LIKELY (50-80%) IN THE WESTERN UP, AND PATCHY
FROST (20-40%) IS POSSIBLE ELSEWHERE AWAY FROM SHORELINES.
- WEDNESDAY MORNING, AREAS OF FROST ARE LIKELY (60-90%) IN THE
WESTERN UP AND PATCHY FROST IS POSSIBLE (20-40%) ELSEWHERE AWAY FROM
SHORELINES.
- DRY PATTERN WITH PERSISTENT HIGH PRESSURE SETS UP THROUGH MUCH OF
THIS WEEK. BELOW-AVERAGE TEMPERATURES THROUGH TOMORROW GIVES WAY TO
ABOVE-NORMAL TEMPERATURES LATE WEEK.
DISCUSSION
ISSUED AT 340 AM EDT TUE SEP 22 2026
AS OF 06Z THIS MORNING, RAP SURFACE ANALYSIS SHOWS A HIGH PRESSURE
CENTER OCCUPYING THE WESTERN PORTION OF QUEBEC AT 1030 MB, WITH
TRAILING 1027-28 MB OVER THE UP. FROM GOES NIGHTTIME MICROPHYSICS,
THE MORE SUBSTANTIAL CLOUD COVER HAS MOVED SOUTH THROUGHOUT THE
NIGHT, LEAVING ONLY HIGH, THIN CLOUDS ATOP SOME PARTS OF THE CWA.
WITH OVER FIVE HOURS YET TO BEFORE SUNRISE, SURFACE TEMPERATURE
OBSERVATIONS ARE STARTING TO DIP INTO THE LOW 30S, WITH MOST
REMAINING IN THE HIGH 30S OR LOW 40S (EXCEPTING THOSE WITHIN
LAKESHORE VICINITY, WHICH SIT CLOSER TO 50F). FROST AND FREEZE
HEADLINES ARE CURRENTLY IN EFFECT, AND TEMPERATURES ARE CURRENTLY ON
TRACK TO ACHIEVE WIDESPREAD FROST IN INTERIOR LOCATIONS. OVER LAND,
WINDS HAVE GONE LARGELY CALM FOR THE NIGHT EXCEPT FOR SOME COASTAL
LOCATIONS WHICH SHOW WINDS MOSTLY LESS THAN 10 MPH IN A LAND BREEZE
PATTERN.
THE ROBUST QUEBEC HIGH SLOWLY PROPAGATES EAST THROUGH THE DAY TODAY
WHILE PERSISTENT RIDGING REMAINS OVER THE UPPER GREAT LAKES. LIGHT,
EASTERLY FLOW CONTINUES AS THE DEEPENING CANADIAN HIGH PRESSURE
DEFLECTS A COMPACT LOW SPINNING TOWARD THE SOUTHERN GREAT LAKES.
WITH HIGHS IN THE LOW TO MID 60S TODAY, A SLIGHTLY WARMER LOW-LEVEL
TEMPERATURE PROFILE IN THE LATTER HALF OF THE DAY WILL CAUSE FROST
FORMATION TO STRUGGLE A BIT MORE DESPITE EFFICIENT (CLEAR SKY)
COOLING. THE NBM SHOWS A SIMILAR BUT SLIGHTLY SMALLER FOOTPRINT FOR
FROST TOMORROW MORNING, WITH THE AREAS OF WIDESPREAD FROST
RESTRICTED RELATIVE TO THE ONGOING FROST EVENT. THAT SAID, AREAS OF
FROST ARE LIKELY IN SOME PORTIONS OF INTERIOR WEST (50-90%) AND
PATCHY FROST IS POSSIBLE ELSEWHERE (20-60%). LATER THIS WEEK, AS
SURFACE FLOW TURNS SOUTHERLY, OVERNIGHT LOWS ON WEDS NIGHT/THURS
MORNING ARE UNLIKELY TO CATALYZE FROST FORMATION.
WITH DRY AIR IN PLACE ALOFT, WIDESPREAD RELATIVE HUMIDITIES OF 30-
35% ARE LIKELY TUESDAY LATE AFTERNOON. GAYLORD'S 00Z SOUNDING SHOWS
DEEP-LAYER DRY AIR BETWEEN 850 AND 500 MB; MODELED SOUNDINGS
CONTINUE TO PREDICT DEWPOINT DEPRESSIONS IN EXCESS OF 20C FOR THIS
AFTERNOON. HOWEVER, GIVEN LIGHT WINDS AND HIGHS IN THE 60S,
CONDITIONS DO NOT MEET CRITERIA FOR EVEN BORDERLINE OR LIMITED FIRE
WEATHER CONCERNS. EASTERLY FLOW PERSISTS TOMORROW BEFORE BEGINNING
TO VEER SOUTHERLY, LEADING TO INCREASING LOW-LEVEL MOISTURE
WEDNESDAY AND THURSDAY, WITH MINIMUM RHS IN THE 35-40% RANGE ON
WEDNESDAY AND OVER 50% ON THURSDAY.
FURTHER OUT, THOUGH SOME LOW CHANCES OF PRECIP BRUSH THE WESTERN
EDGE OF THE CWA IN THE THURS-FRI TIMEFRAME, THE REMAINDER OF THE
WEEK IS SETUP TO REMAIN DRY, WITH GOOD LARGE-SCALE AGREEMENT AMONGST
ENSEMBLES INTO SATURDAY. THE NEXT CHANCE FOR POTENTIALLY MEANINGFUL
PRECIPITATION AT THIS TIME IS LATE ON SATURDAY INTO SUNDAY, IN
CONJUNCTION WITH A MID-LEVEL TROUGH ENTERING THE PNW LATER THIS WEEK.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 103 AM EDT TUE SEP 22 2026
VFR CONDITIONS PREVAIL THROUGHOUT THE FORECAST AS HIGH PRESSURE TO
THE NORTH AND NORTHEAST OF THE REGION SUPPRESSES CHANCES OF FOG
FORMATION BELOW 10%. WINDS WILL BE LIGHT AND VARIABLE DURING
OVERNIGHT PERIODS, INCREASING TO 5-10 KT DURING THE AFTERNOON HOURS
OUT OF THE EAST TO SOUTHEAST BEFORE DECREASING AGAIN IN THE
EVENING.
MARINE
ISSUED AT 340 AM EDT TUE SEP 22 2026
LIGHT, EASTERLY WINDS CONTINUE THROUGH THIS AFTERNOON AS THE ROBUST
QUEBEC (FORMERLY ONTARIO) HIGH PROGRESSES SLOWLY EAST. REGIONAL HIGH
PRESSURE PERSISTS THROUGH THE WEEK WHILE WINDS VEER SLOWLY TO
SOUTHERLY BY THURSDAY. PERIODS OF HIGHER WIND SPEEDS WILL OCCUR AS
THE PRESSURE GRADIENT TIGHTENS AT TIMES. FRIDAY, WINDS GO VERY LIGHT
(GUSTS < 10 KNOTS) AND WAVES DIMINISH TO LESS THAN 1 FOOT.
FOR LAKE SUPERIOR: LIGHT, EASTERLY WINDS PICK UP TO AROUND 20KTS IN
THE LATE AFTERNOON AND EVENING HOURS TUESDAY AND WEDNESDAY PRIOR TO
LAYING DOWN BEFORE SUNRISE THE FOLLOWING DAY. CORRESPONDINGLY, WAVE
HEIGHTS INCREASE TO 1-2FT AS WINDS INCREASE DURING THE AFTERNOON AND
EVENING HOURS. THURSDAY AND FRIDAY, WINDS COME IN GENERALLY FROM THE
SOUTH TO SOUTHEAST, AND WHILE GUSTS TO AROUND 20KTS WILL BE POSSIBLE
OVER THE EAST-CENTRAL PORTIONS OF THE LAKE THURSDAY (WITH WAVES TO
2-3 FEET), WINDS FALL BELOW 10KTS ACROSS THE ENTIRE LAKE FRIDAY.
FOR THE BAY OF GREEN BAY AND NORTHERN LAKE MICHIGAN: EASTERLY FLOW
FILLS IN STARTING THIS MORNING AND THROUGHOUT THE DAY TODAY, WITH
WIDESPREAD GUSTS TO 20 KNOTS BY NOON AND GUSTS TO 25 BECOMING MORE
COMMON THIS EVENING. WINDS LAY DOWN SLIGHTLY (GUSTS TO 15 KNOTS) FOR
A BRIEF PERIOD WEDNESDAY MORNING BEFORE INCREASING AGAIN IN SIMILAR
FASHION FOR WEDNESDAY AFTERNOON AND NIGHT. WINDS SHIFT OVER TO THE
E/SE THURSDAY AND FRIDAY, FALLING BELOW 15KTS. WAVES INCREASE FROM 2-
3 FEET IN LAKE MICHIGAN THIS MORNING TO 4-5 FEET THIS EVENING BEFORE
SUBSIDING TO 3 FEET WEDNESDAY MORNING.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR
MIZ002-005>007-009-011-013-014-085.
FREEZE WARNING UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR
MIZ004-010-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
DISCUSSION...RE
AVIATION...GS
MARINE...RE/LC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page