787
FXUS63 KMQT 201904
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
304 PM EDT THU AUG 20 2026
KEY MESSAGES
- SCATTERED SHOWERS AND A FEW THUNDERSTORMS MOVE WEST TO EAST THIS
EVENING INTO TONIGHT. RAINFALL AMOUNTS WILL BE LIGHT, GENERALLY
AROUND 0.1" OR LESS, THOUGH SOME HIGHER AMOUNTS ARE POSSIBLE IN
STORMS.
- SHOWERS AND STORMS RE-DEVELOP ALONG THE COLD FRONT OVER THE
CENTRAL UP FRIDAY AFTERNOON, THEN MOVE EASTWARD INTO THE EVENING.
ADDITIONAL RAINFALL TOTALS ARE EXPECTED TO BE 0.1" OR LESS, THOUGH
HIGHER AMOUNTS ARE POSSIBLE IN STORMS.
DISCUSSION
ISSUED AT 304 PM EDT THU AUG 20 2026
AFTERNOON WATER VAPOR IMAGERY SHOWS NICELY THE MIDLEVEL SHORTWAVE
OVER NORTH DAKOTA, WITH RAP ANALYSIS SHOWING SURFACE LOW PRESSURE
OVER THE ND/MN BORDER REGION. WAA OUT AHEAD OF THIS, COINCIDENT WITH
A 30-40KT LLJ, HAS TOUCHED OFF CONVECTION OVER EASTERN MN AND
WESTERN LAKE SUPERIOR. ASSOCIATED MIDLEVEL CLOUD COVER CONTINUES TO
WORK EASTWARD INTO THE UP, AND THOUGH SOME WEAK RADAR RETURNS HAVE
DRIFTED OVER THE WESTERN UP AT TIMES, DRY AIR IS WINNING OUT SO FAR
(DEWPOINT DEPRESSIONS ON THE ORDER OF 20 DEGREES) AND PREVENTING
ANYTHING FROM REACHING THE GROUND. WITH THAT, HAVE PULLED BACK THE
ONSET TIMING OF CONVECTION OVER THE WESTERN UP CLOSER TO 00Z. BY
THEN, A FEW HUNDRED J/KG OF CAPE INDICATE THAT SOME THUNDER WILL BE
POSSIBLE, AND THIS CONTINUES OVERNIGHT AS THE INITIAL BATCH OF
SHOWERS AND STORMS WORKS EASTWARD. HEAVY RAINFALL IS NOT EXPECTED,
WITH MOST SPOTS SEEING A TENTH OF AN INCH OR LESS. HOWEVER, HIGHER
TOTALS OF A QUARTER-INCH WOULD BE POSSIBLE IN STORMS (HREF SHOWING
EMBEDDED 30-50% PROBABILITY OF SUCH TOTALS PER 6-HOURLY PERIOD
TONIGHT). OTHERWISE, EXPECT TEMPERATURES, RISING COMFORTABLY THROUGH
THE 70S THIS AFTERNOON, TO FALL BACK INTO THE 50S TO NEAR 60
OVERNIGHT.
FRIDAY, THE SURFACE LOW OFF TO OUR WEST TRACKS THROUGH THE UP
(PERHAPS OPENING UP INTO A SURFACE TROUGH). THIS BRINGS A COLD FRONT
THROUGH THE AREA, WHICH LOOKS TO BE DRAPED SOMEWHERE ACROSS THE
CENTRAL UP BY MID-MORNING. DESTABILIZATION AHEAD OF THE FRONT OVER
THE CENTRAL AND EASTERN UP WILL ALLOW SHOWERS AND STORMS TO
REDEVELOP INTO THE AFTERNOON, BUT WITH VERY LIMITED SHEAR AND MUCAPE
BELOW 1000J/KG, STRONG TO SEVERE STORMS ARE NOT EXPECTED. THIS
SHOULD NOT BE A WASHOUT, AGAIN WITH MOST AREAS RECEIVING ADDITIONAL
RAINFALL TOTALS OF A TENTH OF AN INCH OR LESS. HOWEVER, ENSEMBLES
SHOW AS MUCH AS A 50% CHANCE FOR HIGHER EMBEDDED TOTALS IN EXCESS OF
A QUARTER-INCH IN HEAVIER DOWNPOURS. FRIDAY IS LOOKING OTHERWISE
BREEZY AHEAD OF THE FRONT, WITH SOUTHERLY WIND GUSTS TO AROUND 20MPH
OVER THE EASTERN UP. TEMPERATURES PEAK IN THE LOWER TO MID 70S
BEHIND THE FRONT, AND THE MID TO UPPER 70S AHEAD OF IT.
ADDITIONAL CHANCES FOR SHOWERS AND STORMS RETURN FOR SATURDAY AS A
MIDLEVEL LOW DROPS INTO NORTHERN ONTARIO, SENDING ADDITIONAL
SHORTWAVES AND A SHOT OF COLD AIR ADVECTION INTO THE GREAT LAKES.
THAT SAID, THE MAIN STORY WILL BE MARINE HAZARDS AND GUSTY NORTHERLY
WINDS SATURDAY/SUNDAY. MODEST PRESSURE RISES COUPLED WITH COLD AIR
ADVECTION (850 MB TEMPS BETWEEN 3-6C SUNDAY) WILL CREATE NORTHERLY
GUSTS 20-30 KTS WITH A 40-50% CHANCE OF GALES TO 35 KTS OVER THE
EASTERN PORTIONS OF THE LAKE.
MODEL DISCREPANCIES FOLLOW INTO NEXT WEEK, THOUGH SUNDAY AND MONDAY
LOOKS MAINLY DRY, FOLLOWED BY ON AND OFF RAIN CHANCES THE REST OF
THE FORECAST PERIOD AS A SERIES OF SHORTWAVES DROP THROUGH THE GREAT
LAKES.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 214 PM EDT THU AUG 20 2026
MOSTLY VFR CONDITIONS ARE EXPECTED DURING THE 18Z TAF PERIOD, BUT
THE DRY AIRMASS IN PLACE EVENTUALLY GIVES WAY TO -SHRA AND
POTENTIALLY (20-40% CHANCE) A FEW -TSRA (HIGHEST CHANCE AT IWD).
PRECIP ARRIVES AT IWD AND CMX FIRST LATE THIS AFTERNOON, CONTINUING
INTO THE EARLY OVERNIGHT HOURS. -SHRA ARRIVES AT SAW TONIGHT,
HOLDING ON AND OFF INTO FRIDAY MORNING BEFORE DRY WEATHER RETURNS.
THE EXCEPTION TO VFR CONDITIONS ARRIVES BEHIND THE COLD FRONT EARLY
FRIDAY MORNING WHEN CIGS LOWER TO IFR AT IWD AND POSSIBLY MVFR AT
CMX (30-50% CHANCE).
OTHERWISE SOUTHERLY WINDS GENERALLY HOLD AROUND 5 TO 10 KTS THROUGH
THE PERIOD, BECOMING NORTHWEST BEHIND THE COLD FRONT FRIDAY
MORNING. SLIGHT DEVIATIONS TO THAT ARE WHERE LAKE BREEZE INFLUENCES
YIELD AN EAST WIND AT CMX IN THE NEXT 1 TO 2 HOURS AND SOME VARIABLE
CONDITIONS AT SAW THIS AFTERNOON.
MARINE
ISSUED AT 304 PM EDT THU AUG 20 2026
LAKE SUPERIOR - ESE WIND GUSTS PICK UP TO AROUND 20KTS OVER THE EAST-
CENTRAL PORTIONS OF THE LAKE TONIGHT, THEN GUSTS FALL BACK BELOW
20KTS FRIDAY AFTERNOON WHILE A PASSING COLD FRONT CAUSES WINDS TO
SHIFT OVER TO THE NW. THE MAIN MARINE HAZARDS RETURN SATURDAY AND
SUNDAY AS A PAIR OF SYSTEMS BRING MODEST PRESSURE RISES AND COLD AIR
ADVECTION OVER THE LAKE RESULTING IN GUSTY N TO NW WINDS UPWARDS OF
20-30 KTS BEGINNING SATURDAY MORNING THROUGH SUNDAY NIGHT. AT THIS
TIME, THERE IS A LOW CHANCE (30-50%) FOR A FEW GALES TO 35 KTS
MAINLY BETWEEN MARQUETTE AND WHITEFISH POINT. WINDS FALL BACK BELOW
20KTS SUNDAY NIGHT, AND STAY MAINLY BELOW 20KTS THROUGH EARLY NEXT
WEEK.
NORTHERN BAY OF GREEN BAY AND NORTHERN LAKE MICHIGAN - SOUTHERLY
WIND GUSTS UP TO 15-20KTS WILL BE POSSIBLE OVER THE BAY BEGINNING
LATER THIS EVENING, BUT BECOME MORE COMMON OVER THE BAY AND NORTHERN
LAKE MICHIGAN LATE TONIGHT AND LINGER THROUGH FRIDAY AS LOW PRESSURE
TRAVERSES THE AREA. THIS RESULTS IN WAVES BUILDING BETWEEN 1-3 FT
(GREATEST IN THE OPEN WATERS CLOSER TO LAKE MICHIGAN). A BRIEF
REPRIEVE IN WINDS COMES FRIDAY NIGHT BEHIND A WEAK COLD FRONT,
HOWEVER, TWO SYSTEMS THEN DIVE INTO THE AREA SATURDAY AND SUNDAY,
RESULTING IN GUSTY NORTH TO NORTHWEST WINDS 15-25 KTS THROUGH SUNDAY
NIGHT. WIND GUSTS BRIEFLY FALL BACK BELOW 20KTS FOR MONDAY BEFORE
POTENTIALLY INCREASING AGAIN INTO THE MIDWEEK PERIOD.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
DISCUSSION...LC
AVIATION...77
MARINE...LC
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