938  
FXUS63 KMQT 122341  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
741 PM EDT WED AUG 12 2020  
   
SHORT TERM
 
(THIS EVENING THROUGH THURSDAY)  
ISSUED AT 328 PM EDT WED AUG 12 2020  
 
OUTSIDE OF A FEW PASSING MID-LEVEL CLOUDS, UPPER MICHIGAN REMAINS  
MOSTLY CLEAR THIS AFTERNOON WITH TEMPERATURES CLIMBING INTO THE 80S  
FOR MOST. A DEVELOPING LAKE SUPERIOR LAKE BREEZE CONTINUES TO  
DEVELOP AND PUSH INLAND, AS TEMPERATURES BEHIND THIS BREEZE HAVE  
FALLEN BACK INTO THE 70S. REMNANT CONVECTION ACROSS MN IS THROWING  
SOME CONVECTIVE-INDUCED CIRROSTRATUS CLOUDS ACROSS THE FAR WESTERN  
HALF OF THE CWA OVER THE LAST FEW HOURS, AND WILL CONTINUE TO MOVE  
EASTWARD INTO THIS EVENING.  
 
TONIGHT, A LITTLE BIT OF A CHANGE FROM THE GOING FORECAST AS LATEST  
RUN OF CAMS AND MODELS SUGGEST A CONVECTIVELY-INDUCED PASSING SHRTWV  
WILL BRING A ROUND OF SHRA AND ISO TSRA ACROSS WESTERN LAKE SUPERIOR  
AND FAR WESTERN UPPER MICHIGAN. WAS A LITTLE SKEPTICAL ON COVERAGE  
AND EASTERN EXTENT GIVEN DRIER AIR AND HIGH PRESSURE AHEAD OF  
SHRTWV, BUT THROUGH IN SOME SLIGHT TO CHANCE POPS, MAINLY WEST OF A  
LINE FROM BIG BAY TO WATERSMEET. ADDITIONALLY, MODELS SUGGEST THIS  
WAVE TO OUTRUN SUPPORTING INSTABILITY AND FORCING THAT LINGERS  
BEHIND IT ACROSS MN. WITH THESE INCREASING CLOUDS, INCREASED LOWS  
TONIGHT A FEW DEGREES FROM GOING FCST, FALLING TO EITHER SIDE OF  
60...60S ALONG LAKE SUPERIOR AND UPPER 50S INLAND.  
 
TOMORROW, WEAK WAA AND INCREASING THETA-E ACROSS THE FAR WEST WILL  
HELP INCREASE MOISTURE AND DEWPOINTS ACROSS THE WESTERN HALF OF THE  
UP. HIGH PRESSURE RIDGING EXTENDING WESTWARD FROM CANADA WILL ALLOW  
THE EAST HALF OF THE UP TO REMAIN A LITTLE DRIER, WHILE MODEL  
SOUNDINGS SUPPORT THIS IDEA AS WELL. CONVECTION OVER MN IS EXPECTED  
TO DIMINISH AS IT ADVECTED EASTWARD OVER LAKE SUPERIOR. HIGHS WILL  
CLIMB INTO THE 80S AGAIN, SIMILAR TO THIS AFTERNOON.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 343 PM EDT WED AUG 12 2020  
 
A SHRTWV RIDGE WILL MOVE OUT TO OUR EAST THURSDAY NIGHT AND FRIDAY  
AS A LONGWV TROUGH MOVES THROUGH THE AREA FROM FRIDAY TO SUNDAY,  
BRINGING SHOWERS AND THUNDERSTORMS TO UPPER MICHIGAN AS IT SLOWLY  
PASSES. BEHIND THE LONGWV, TEMPERATURES WILL DROP FROM ABOVE  
NORMAL TO NEAR OR BELOW NORMAL AS CAA BRINGS IN COOLER, DRIER  
CANADIAN AIR. MORE DETAILS FOR THE FORECAST FOLLOW BELOW.  
 
THURSDAY NIGHT AND FRIDAY, THE HUDSON BAY HIGH BEGINS TO MOVE OUT  
EAST AS A LONGWV TROUGH SLOWLY FOLLOWS BEHIND IT, DRAGGING A SHRTWV  
TROUGH THROUGH NE MINNESOTA. PWATS HAVE 2 STD ANOMALIES OVER NE  
MINNESOTA/N ONTARIO, AND IVTS SHOW MOISTURE FROM THE PACNW AND  
STRAINED MOISTURE FROM GULF (DUE TO THE GULF MOISTURE BEING  
PARTIALLY BLOCKED BY A LOW OVER THE OHIO RIVER VALLEY) ENHANCING  
CONVECTION NEAR NE MINNESOTA. CAPE AND WIND SHEAR VALUES SEEM TO  
SUPPORT THE IDEA OF SOME STRONG STORMS BEING POSSIBLE OVER NE  
MINNESOTA THURSDAY NIGHT INTO FRIDAY, WITH CAPE VALUES GETTING TO  
2500 J/KG AND WIND SHEAR REACHING 30+ KNOTS. HOWEVER, THESE VALUES  
DROP OFF QUICKLY NEAR LAKE SUPERIOR. THEREFORE, ALTHOUGH SOME  
STORMS, WITH A FEW POSSIBLY BECOMING STRONG, WILL PROBABLY FORM  
OVER FAR WESTERN LAKE SUPERIOR, THERE SHOULDN'T BE A CONCERN FOR  
SEVERE WEATHER THURSDAY NIGHT AND FRIDAY FOR UPPER MICHIGAN AS  
CONVECTION SHOULD BE SUPPRESSED BY THE ANOMALOUS HIGH PRESSURE  
SHRTWV OVER OUR AREA. THERE MAY BE A STRAY SHOWER OR THUNDERSTORM  
OVER THE WEST, BUT THAT SHOULD BE ABOUT IT IF CONVECTION WAS TO  
OCCUR OVER UPPER MICHIGAN. SO, SAVE FOR THE POSSIBLY STRONG  
THUNDERSTORMS OVER THE FAR WESTERN LAKE THURSDAY NIGHT AND  
FRIDAY, THERE SHOULDN'T BE ANY HAZARDOUS WEATHER THAT NEEDS TO BE  
CONSIDERED. THIS HIGH PRESSURE RIDGE WILL ALSO KEEP TEMPERATURES  
ABOVE NORMAL AS IT WILL KEEP WARM AIR (15-20 C AT 850MB) NEAR THE  
UPPER PENINSULA.  
 
FRIDAY NIGHT INTO SUNDAY, THE LONGWV TROUGH WILL BRING A COLD FRONT  
THROUGH THE AREA. THIS FRONT SHOULD DROP THE TEMPERATURES EACH DAY  
AS THE FRONT SLOWLY MOVES THROUGH THE AREA FROM WEST TO EAST. A  
DECREASE IN THE PWAT ANOMALIES SHOW THAT THE AMOUNT OF MOISTURE FROM  
THE PACNW AND GULF FOR THIS SYSTEM IS DECREASING WITH TIME. ALSO,  
CAPE VALUES ARE ALSO NOT AS NEARLY AS IMPRESSIVE WHEN COMPARED TO NE  
MINNESOTA THURSDAY NIGHT AND FRIDAY; MODEL GUIDANCE HAS CAPE ONLY  
GETTING TO 2000 J/KG AT MOST IN A FEW SPOTS, MOSTLY DURING THE  
AFTERNOON SATURDAY. WIND SHEAR SHOULDN'T BE HINDERED THOUGH, AS  
VALUES LOOK TO REMAIN NEAR 30 KNOTS. THEREFORE, IT SEEMS THAT AS THE  
FRONT TRAVELS THROUGH THE UPPER PENINSULA OVER THE WEEKEND, SHOWERS  
AND THUNDERSTORMS WILL DIMINISH AND WEAKEN AS THE FRONT MAKES ITS  
WAY EAST, MAKING SEVERE WEATHER UNLIKELY. TEMPERATURES SHOULD  
DROP CLOSER TO NORMAL WITH EACH PASSING DAY, AS THE SMALL  
POSITIVE TEMPERATURE ANOMALY VANISHES AS THE FRONT MOVES THROUGH.  
 
THE EARLY PART OF THE WORKWEEK NEXT WEEK SHOULD SEE DRIER AND COOLER  
CONDITIONS AS A CANADIAN AIRMASS MAKES ITS WAY OVER THE UPPER  
PENINSULA. A STRAY SHOWER OR TWO IS NOT OUT OF THE REALM OF  
POSSIBILITY, ESPECIALLY IF THE FRONT MOVES SLOWER THAN EXPECTED OVER  
THE WEEKEND. HOWEVER, THE BEGINNING OF THE WORKWEEK SHOULD BE  
RELATIVELY DRY AS A HIGH PRESSURE RIDGE MOVES OVER THE WESTERN  
PLAINS; CAA WILL ALSO HELP TO KEEP THINGS DRY, AS IT WILL SUPPRESS  
CONVECTION THROUGH SUBSIDENCE. TEMPERATURES MAY GET ANOMALOUSLY  
COOL, ESPECIALLY MONDAY AND TUESDAY, AS THAT IS WHEN THE CAA LOOKS  
TO BE STRONGEST (HINTED AT BY THE ENS AND NAEFS). TEMPERATURES  
APPEAR TO BE NEAR NORMAL FOR WEDNESDAY.  

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)  
ISSUED AT 740 PM EDT WED AUG 12 2020  
 
WITH RELATIVELY DRY LOW-LEVEL AIR MASS TO REMAIN OVER THE AREA,  
EXPECT VFR CONDITIONS TO PREVAIL AT KIWD/KCMX/KSAW THRU THIS FCST  
PERIOD. A DISTURBANCE MOVING ACROSS THE AREA TONIGHT, MAY GENERATE A  
SOME SHRA THAT WILL AFFECT KIWD AND PERHAPS KCMX. NOT EXPECTING  
CONDITIONS TO FALL OUT OF VFR IF A SHRA OCCURS.  

 
   
MARINE
 
(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)  
ISSUED AT 328 PM EDT WED AUG 12 2020  
 
CONVECTION ONGOING ACROSS MN THIS AFTERNOON WILL PASS OVER WESTERN  
LAKE SUPERIOR TONIGHT, AS WINDS GUST UP TO AROUND 20 KNOTS FROM THE  
SE. WINDS FALL BLO 20 KNOTS AGAIN FOR FRIDAY BEFORE INCREASING UP TO  
20 KNOTS AGAIN ON SATURDAY FROM THE SOUTH AHEAD OF AN APPROACHING  
TROUGH AND COLD FRONT. ANOTHER COLD FRONT IS PROGGED TO MOVE OVER  
THE LAKE DURING THE START OF NEXT WEEK, WHICH MAY BRING WINDS TO  
AROUND 25 KNOTS FROM THE NW.  

 
   
MQT WATCHES/WARNINGS/ADVISORIES
 
 
UPPER MICHIGAN...  
NONE.  
LAKE SUPERIOR...  
NONE.  
LAKE MICHIGAN...  
NONE.  

 
 

 
 
SHORT TERM...JAW  
LONG TERM...TAP  
AVIATION...ROLFSON  
MARINE...JAW  
 
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