300  
FXUS63 KMQT 190521  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
121 AM EDT SAT AUG 19 2017  
   
SHORT TERM
 
(THIS EVENING THROUGH SATURDAY)  
ISSUED AT 349 PM EDT FRI AUG 18 2017  
 
TONIGHT: WRAP-AROUND MOISTURE WILL CONTINUE TO FLOW INTO MUCH OF THE  
CENTRAL AND EASTERN PORTIONS OF THE U.P. THIS EVENING, BEFORE SLOWLY  
EXITING OFF TO THE FAR EASTERN PORTIONS OF THE AREA OVERNIGHT. IN  
ADDITION TO THE WRAP-AROUND MOISTURE, ANOTHER SHORWAVE ROUNDING THE  
BASE OF THE OVERALL TROUGHING PATTERN WILL SLIDE ACROSS THE U.P.  
THIS MAY TOUCH OFF SOME EARLY EVENING SHOWERS OVER THE FAR WESTERN  
U.P.; HOWEVER, INSTABILITY IS FAIRLY MINIMAL DUE TO THE CONTINUED  
CLOUD COVER ACROSS THE AREA, SO THIS WOULD LIKELY BE LIMITED TO ANY  
SHOWERS THAT FORM OVER MN AND SLIDE INTO THE FAR WEST. OTHERWISE, AS  
THE SHORTWAVE SHIFTS EASTWARD TONIGHT, SKIES SHOULD BEGIN TO CLEAR  
OVER THE WEST HALF. IF THE CLEARING OCCURS EARLY ENOUGH, RADIATIONAL  
COOLING MAY ALLOW SOME PATCHY FOG TO FOR OVERNIGHT OVER THE WEST  
HALF. TEMPERATURES WILL BE KEPT A BIT WARMER OVER THE EAST WHERE  
CLOUD COVER IS LIKELY TO LINGER THROUGH MUCH OF THE NIGHT.  
 
SATURDAY: THE MAIN TROUGH AXIS WILL CONTINUE TO SHIFT EASTWARD  
THROUGH THE DAY SATURDAY ALLOWING FOR A STEADY WARMING TREND ACROSS  
THE AREA. THIS WILL ESPECIALLY BE TRUE ACROSS THE WEST HALF UNDER  
THE APPROACHING RIDGE. THE EAST HALF, STILL REMAIN UNDER THE  
INFLUENCE OF THE DEPARTING TROUGH, WILL SEE SOME ISOLATED TO  
SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS DEVELOP ALONG LAKE  
BREEZE BOUNDARIES. THERE WILL BE SOME ADDITIONAL SUPPORT, STEEPER  
LAPSE RATES, FROM YET ANOTHER SHORTWAVE PROGGED TO SLIDE ACROSS THE  
EAST HALF DURING PEAK HEATING. AGAIN, THE MAIN FOCUSING MECHANISM  
WILL BE THE LAKE BREEZE BOUNDARIES OVER THE EAST HALF, SO THE  
SHOWERS AND THUNDERSTORMS SHOULD BE LIMITED TO THOSE AREAS. CAPE  
VALUES ARE EXPECTED TO BE IN THE 500-800J/KG RANGE ACROSS THE SOUTH  
CENTRAL AND EAST ALONG WITH SHEAR VALUES IN THE 25 TO 35 KNOT RANGE.  
THIS MAY ALLOW FOR A COUPLE STRONGER STORMS TO DEVELOP ALONG THE  
BOUNDARIES, ESPECIALLY AT THE ONSET OF THUNDERSTORM DEVELOPMENT. THE  
MAIN THREAT WOULD BE HAIL AND GUSTY WINDS. THE REST OF THE U.P. MAY  
ONLY END UP SEEING SOME AFTERNOON CU. HIGH TEMPERATURES WILL WARM  
INTO THE MID TO UPPER 70S ACROSS MOST OF THE AREA WITH A FEW 80  
DEGREE READINGS POSSIBLE.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 346 PM EDT FRI AUG 18 2017  
 
SATURDAY NIGHT AND SUNDAY: WEAK UPPER LEVEL RIDGING AND A SURFACE  
HIGH PRESSURE RIDGE ARE EXPECTED TO BUILD ACROSS THE UPPER GREAT  
LAKES REGION FOR SATURDAY NIGHT INTO SUNDAY MORNING. THIS WILL ALLOW  
WINDS TO DIMINISH ACROSS THE AREA AND ALLOW SKIES TO BECOME CLEAR TO  
PARTLY CLOUDY THROUGH SUNDAY MORNING. SUNDAY AFTERNOON A WEAK  
SURFACE TROUGH IS EXPECTED TO SLIDE IN FROM THE WEST IN RESPONSE TO  
A SHORTWAVE MOVING THROUGH NW ONTARIO, WHICH WILL SPREAD SCATTERED  
SHOWERS AND THUNDERSTORMS INTO THE WEST HALF OF THE U.P. MAINLY LATE  
AFTERNOON THROUGH THE EVENING HOURS. SUNDAY AFTERNOON WILL BE VERY  
WARM AHEAD OF THE SURFACE TROUGH WITH MIXING OF AROUND 18C TEMPS  
FROM H85 THERMAL RIDGE OVERHEAD TO SFC RESULTING IN MANY LOCATIONS  
WARMING INTO THE MID 80S.  
 
MONDAY INTO TUESDAY: THE NEXT AREA OF BROADER MID-LEVEL TROUGHING  
WILL SHIFT EASTWARD TOWARD THE UPPER GREAT LAKES FOR THIS TIME  
PERIOD. AS THIS HAPPENS, A COLD FRONT IS EXPECTED TO SHIFT INTO THE  
AREA MONDAY AFTERNOON AND THEN SLOWLY SHIFT EASTWARD INTO TUESDAY  
AFTERNOON. AS MOISTURE, FORCING AND INSTABILITY (MLCAPES APPROACH  
1000 J/KG) INCREASE ALONG AND AHEAD OF THE FRONT, EXPECT SHOWERS,  
THUNDERSTORMS AND CLOUD COVER TO INCREASE ACROSS THE AREA MONDAY  
AFTERNOON INTO TUESDAY. ALSO NOT OUT OF THE QUESTION THERE COULD BE  
SOME ISOLATED SEVERE STORMS MON AFTERNOON INTO EVENING GIVEN  
INSTABILITY AND DEEP LAYER SHEAR INCREASING TO 30-35 KNOTS.  
 
WEDNESDAY: WITH THE BROAD MID-LEVEL TROUGH STILL LINGERING OVER THE  
AREA AND THE MODELS HINTING AT ANOTHER SHORTWAVE MOVING DOWN FROM  
ONTARIO, SCATTERED SHOWERS COULD PERSIST INTO WED. THE 12Z ECMWF AND  
CMC MODELS ALSO SUGGEST THE POTENTIAL FOR SOME LAKE ENHANCEMENT TO  
SHOWERS ON WEDNESDAY AS H85 TEMPS FALL NEAR 7C WED AFTERNOON. GIVEN  
MID-LAKE SUPERIOR TEMPS 15-16C THIS WOULD CREATE A LAKE-H85 DELTA-T  
OF AROUND 8C. WITH A POSSIBLE SHORTWAVE MOVING THROUGH THE AREA  
COULD SEE A HYBRID OF LAKE ENHANCED AND DIURNAL INSTABILITY SHOWERS.  
 
THURSDAY AND FRIDAY: SHOULD SEE A DRYING TREND TOWARD THE END OF  
NEXT WEEK AS BROAD SFC RIDGING BUILDS IN FM NORTHWEST OF THE LAKE.  
TEMPERATURES WILL LIKELY BE BELOW NORMAL FOR THE LATTER HALF OF THE  
WORK WEEK.  

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)  
ISSUED AT 120 AM EDT SAT AUG 19 2017  
 
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. THERE IS SOME  
FOG DEVELOPING OVER THE WESTERN U.P. BUT THAT IS EXPECTED TO STAY  
OUT OF KIWD.  

 
   
MARINE
 
(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)  
ISSUED AT 349 PM EDT FRI AUG 18 2017  
 
NORTHWEST WINDS WILL GUST TO 20 TO 30 KNOTS OVER THE EASTER PORTIONS  
OF LAKE SUPERIOR THROUGH EARLY THIS EVENING AS THE PRESSURE GRADIENT  
SLOWLY RELAXES ACROSS THE AREA. WINDS WILL THEN REMAIN AT OR BELOW  
20 KNOTS THROUGH THE FIRST HALF OF THE WORK WEEK.  

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

 
 

 
 
SHORT TERM...KEC  
LONG TERM...VOSS  
AVIATION...TITUS  
MARINE...KEC  
 
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