488  
FXUS63 KMQT 221134  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
734 AM EDT THU AUG 22 2019  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 417 AM EDT THU AUG 22 2019  
   
..A BRIEF TASTE OF FALL HAS ARRIVED
 
 
CHILLY PREDAWN TEMPERATURES WERE OBSERVED INLAND FROM LAKE SUPERIOR,  
AS LOWS DROPPED INTO THE 40S FOR MANY LOCATIONS. CLOSER TO THE BIG  
LAKE, NORTHERLY FLOW COMING ONSHORE KEPT LOWS IN THE 50S AND  
LOWER 60S FOR MOST LOCATIONS. SATELLITE TRENDS THIS MORNING SHOW MID-  
LEVEL CLOUDS SPREADING TO THE SOUTHEAST AS ANOTHER SHORTWAVE DIGS  
SOUTH TOWARDS THE REGION. HOWEVER, MUCH OF THE UPPER PENINSULA  
REMAINED CLOUD-FREE THIS MORNING, OUTSIDE OF THE WEST.  
 
TODAY WILL BE COOLER COMPARED TO YESTERDAY, WITH PREDOMINATELY  
NORTHERLY WIND ACROSS THE AREA. CLOUDS CURRENTLY OFF TO OUR NORTH  
AND WEST WILL GRADUALLY WORK INTO THE AREA, AND INCREASE IN  
COVERAGE AS DIURNAL HEAT AND COLD AIR ALOFT FAVOR THE DEVELOPMENT OF  
STRATOCU LATER TODAY. CLOUD COVER LOOKS MORE WIDESPREAD ACROSS THE  
WEST HALF OF UPPER MICHIGAN, WHERE DIURNAL HEATING WILL ALLOW FOR  
LOCAL DESTABILIZATION WITHIN THE BOUNDARY LAYER. THE DESTABILIZATION  
ACROSS THE WEST AND CENTRAL THIS AFTERNOON DOES LOOK TO FAVOR THE  
DEVELOPMENT OF DIURNALLY DRIVEN RAIN SHOWERS. CONFIDENCE ISN'T HIGH  
IN REGARDS TO HOW WIDESPREAD THESE RAIN SHOWERS WILL GET, BUT GIVEN  
THE COLD AIR ALOFT AND A NARROW POCKET OF UNSTABLE AIR TOWARDS THE  
TOP OF THE BOUNDARY LAYER, CERTAINLY LOOKS LIKE A DAY FOR CONVECTIVE  
RAIN SHOWERS. OUT EAST, NORTHERLY FLOW OFF OF LAKE SUPERIOR  
FUNNELING DOWN INTO LAKE MICHIGAN SHOULD KEEP CONDITIONS  
MORE STABLE, WITH LESS CLOUDS. THESE STABLE CONDITIONS WILL INHIBIT  
THE DEVELOPMENT OF AFTERNOON SHOWERS. HOWEVER, OUT EAST, WINDS OFF  
OF LAKE SUPERIOR, AND REMNANT STRONGER WINDS ALOFT WILL MAKE FOR  
GUSTIER WINDS AT TIMES LATE THIS MORNING AND AFTERNOON. THE  
LINGERING DRY CONDITIONS ACROSS THE AREA, BUT COOLER TEMPERATURE ARE  
EXPECTED TO KEEP RHS IN THE 40-55% RANGE, LOCALLY DRIEST ACROSS THE  
SOUTHERN PARTS OF UPPER MICHIGAN ACROSS THE SOUTH CENTRAL AND EAST,  
WHERE DOWNSLOPING NORTHERLY WINDS HELP DRY THINGS OUT FURTHER.  
 
TONIGHT, HIGH PRESSURE STARTS TO DROP SOUTH INTO THE WESTERN PARTS  
OF UPPER MICHIGAN. THIS INCREASED SUBSIDENCE AND LOCALLY VEERING OF  
THE WINDS ACROSS THE INTERIOR PARTS OF UPPER MICHIGAN DOES LOOK LIKE  
IT WILL FAVOR CLEARING SKIES. GIVEN THE ALREADY DRY AIR MASS  
EXPECTED TO BE IN PLACE, WITH AMPLE RADIATIONAL COOLING AND  
DECOUPLING OF THE NOCTURNAL BOUNDARY LAYER, OVERNIGHT LOWS LOOK TO  
TANK INTO THE LOW 30S TO AROUND 40 INLAND FROM THE GREAT LAKES. THE  
AREAS ACROSS THE INTERIOR WEST CERTAINLY LOOK TO BE THE COLD SPOTS  
FRIDAY MORNING, MEANING WE COULD SEE SOME EARLY-SEASON FROST  
DEVELOP. USING THE MODEL CERTAINTY TOOL THIS MORNING, IT APPEARS  
THAT THE CURRENT FORECAST LOWS FALL RIGHT AROUND THE 25TH  
PERCENTILE, SO TOWARDS THE LOWER END OF THE DISTRIBUTION AMONG THE  
MODEL GUIDANCE. THAT BEING SAID, WILL LET THE DAY SHIFT RE-EVALUATE  
LATER TODAY AS TO WHETHER OR NOT A FROST ADVISORY WILL BE NEEDED.  
   
LONG TERM
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 443 AM EDT THU AUG 22 2019  
 
OVER THE LAST 24HRS, NO MAJOR CHANGES HAVE APPEARED IN MEDIUM RANGE  
GUIDANCE/ENSEMBLES WITH RESPECT TO THE PATTERN THRU THE WEEKEND AND  
NEXT WEEK. THE NEXT COUPLE OF DAYS WILL BE A PREVIEW OF FALL AS A  
TROF SWINGS THRU THE GREAT LAKES IN RESPONSE TO A SHARP RIDGE  
EXTENDING FROM S CENTRAL CANADA ACROSS HUDSON BAY. THEN, AS TROFFING  
PUSHES ACROSS WESTERN CANADA THRU THE WEEKEND, THE RIDGE WILL SHIFT  
ACROSS THE GREAT LAKES REGION SAT/SUN, RESULTING IN TEMPS RISING  
BACK TO NORMAL TO A LITTLE ABOVE NORMAL. DURING NEXT WEEK, MEAN  
TROFFING WILL SHIFT FROM WESTERN CANADA TO THE GREAT LAKES REGION AS  
A RIDGE BUILDS OVER WESTERN N AMERICA. THIS PROGRESSION OF THE  
PATTERN SHOULD RESULT IN ABOVE NORMAL TEMPS EARLY NEXT WEEK FALLING  
BACK TO MOSTLY BLO NORMAL MID AND LATE WEEK INTO LABOR DAY WEEKEND.  
WILL LIKELY SEE A PERIOD OF FALL-LIKE COOL WEATHER AGAIN LATE NEXT  
WEEK AS THE MEAN TROF REACHES THE GREAT LAKES. ALTHOUGH IT'S OVER A  
WEEK OUT, EARLY INDICATIONS SUGGEST COOL WEATHER MAY HOLD ON FOR  
MUCH, IF NOT ALL, OF THE LABOR DAY WEEKEND. AS FOR PCPN, PATTERN FOR  
THE NEXT SEVERAL DAYS WILL NOT BE FAVORABLE FOR ANY MEANINGFUL PCPN.  
SOME SPRINKLES/ISOLD -SHRA ARE EXPECTED TODAY UNDER THERMAL TROF.  
COULD SEE A REPEAT ON FRI, THOUGH WITH LESS COVERAGE. DRY WEATHER  
WILL THEN PREVAIL SAT/SUN AS SHARP RIDGING MOVES ACROSS THE WESTERN  
GREAT LAKES. AS THE WESTERN CANADA TROF GRADUALLY SHIFTS E AND  
AMPLIFIES INTO THE N CENTRAL CONUS, A SERIES OF SHORTWAVES WILL BE  
TRACKING OFF THE N PACIFIC AND INTO/THRU THE TROF. IT'S LIKELY THAT  
IT WON'T BE UNTIL SUN NIGHT/MON THAT ONE OF THOSE SHORTWAVES WILL  
PROGRESS FAR ENOUGH DOWNSTREAM TO BRING THE NEXT CHC OF SHRA TO THE  
FCST AREA. AS THE MEAN TROF APPROACHES AND THEN REACHES THE GREAT  
LAKES, EXPECT ADDITIONAL OPPORTUNITIES FOR SHRA THRU THE MID AND  
LATE WEEK PERIOD, BUT AS WAS THE CASE 24HRS AGO, MODELS DON'T  
SUGGEST ANY SIGNIFICANT OR PERSISTENT PCPN EPISODES.  
 
BEGINNING FRI, SFC HIGH PRES RIDGE WILL BE DRIFTING OVER THE AREA  
WITH SFC HIGH PRES CENTER LIKELY DEVELOPING OVER NORTHERN LAKE  
SUPERIOR DURING THE AFTN. WITH 850MB THERMAL TROF STILL OVER THE  
AREA, AT LEAST THRU THE MORNING, WILL LIKELY SEE QUITE A BIT OF  
STRATOCU DEVELOPMENT IN THE MORNING. THESE CLOUDS WILL THEN PROBABLY  
ERODE FROM THE W AND N DURING THE AFTN. NOT OUT OF THE QUESTION THAT  
THERE COULD BE SOME SPRINKLES, BUT WITH LOW-LEVEL FLOW MORE  
ANTICYCLONIC AND A LOWERING SUBSIDENCE INVERSION, POTENTIAL SEEMS  
QUITE LOW. THUS, FCST WILL HAVE NO MENTION OF PCPN. WILL BE ANOTHER  
COOL DAY WITH HIGHS IN THE 60S F. TEMPS MAY REACH 70F IN A FEW SPOTS  
S CENTRAL INTO FAR WESTERN UPPER MI.  
 
SFC HIGH PRES WILL ONLY SLOWLY DRIFT E FRI NIGHT, WITH RIDGING  
LIKELY LINGERING ACROSS CENTRAL AND EASTERN UPPER MI THRU THE NIGHT.  
WITH PRECIPITABLE WATER DOWN AROUND 0.5 INCHES E AND 0.4 INCHES  
CENTRAL, ROUGHLY 50PCT OF NORMAL, EXPECT AN EXCELLENT RADIATIONAL  
COOLING NIGHT. LOWERED MIN TEMPS TO THE LOW END OF AVBL GUIDANCE,  
GENERALLY MID/UPPER 30S IN THE INTERIOR. TRADITIONAL COLD SPOTS  
COULD VERY WELL END UP BLO FREEZING. SO, EXPECT SOME FROST ACROSS  
THE INTERIOR CENTRAL AND E.  
 
RECENT DAYS STRONG MODEL TRENDS FOR A SLOWER PROGRESSION OF BOTH THE  
MID-LEVEL TROF FROM WESTERN CANADA AND THE SHARP RIDGING OVER THE  
GREAT LAKES REGION HAS COME TO AN END. OVER THE LAST 24HRS, MODELS  
HAVE LARGELY STABILIZED ON THE EXPECTED PATTERN PROGRESSION. SO, AT  
THIS POINT, THE WEEKEND STILL LOOKS TO BE DRY AND WARMER. HIGH TEMPS  
SAT/SUN WILL RETURN TO THE 70S UNDER MOSTLY SUNNY SKIES, AND WITH  
DWPTS GENERALLY IN THE UPPER 40S TO MID 50S F, IT WILL BE A PLEASANT  
LATE SUMMER WEEKEND FOR UPPER MI. THERE WILL BE SOME INCREASE IN  
CLOUDS DURING THE DAY SUN. SUN WILL ALSO TURN A BIT BREEZY UNDER  
TIGHTENING PRES GRADIENT BTWN HIGH PRES TO THE E AND COLD FRONT  
MOVING ACROSS THE PLAINS.  
 
PROGRESSION OF SHORTWAVES THRU THE WESTERN TROF WILL PROBABLY SHIFT  
FAR ENOUGH E TO PUSH A COLD FRONT TOWARD UPPER MI MON WITH PASSAGE  
MON NIGHT. THUS, CHC OF OF SHRA/MAYBE THUNDER WILL RETURN FROM W TO  
E SUN NIGHT/MON. LOOKS LIKE A DECENT POTENTIAL OF A WIDESPREAD  
RAINFALL AS TROF BEGINS TO TAKE ON A BIT OF A NEGATIVE TILT AS IT  
ARRIVES. IN ADDITION, IF SOME OF THE GUIDANCE OVER THE LAST 24HRS IS  
CORRECT IN A CENTRAL PLAINS SHORTWAVE BEING CAPTURED AND FORCED NE  
BY THE APPROACHING TROF, PCPN WOULD GET AN ADDITIONAL BOOST. THEN,  
WITH THE MEAN TROF SHIFTING TO THE GREAT LAKES DURING THE REMAINDER  
OF THE WEEK, THERE SHOULD BE ADDITIONAL OPPORTUNITIES FOR SOME PCPN,  
BUT RIGHT NOW, MEDIUM RANGE GUIDANCE DOES NOT SUGGEST ANYTHING  
SIGNIFICANT OR PERSISTENT.  

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)  
ISSUED AT 734 AM EDT THU AUG 22 2019  
 
ONSHORE FLOW AT KSAW COULD RESULT IN A BRIEF WINDOW OF MVFR CEILINGS  
THIS MORNING, BUT OVERALL EXPECT VFR TO PREVAIL TODAY ACROSS ALL  
TERMINALS. RAIN SHOWERS ARE POSSIBLE TODAY ACROSS ALL TERMINALS.  
COVERAGE REMAINS UNCERTAIN, SO ONLY HAVE INCLUDED VCSH IN THE TAFS  
FOR NOW. NORTH WINDS WILL PERSIST TODAY, BEFORE RELAXING AND  
BECOMING VARIABLE OVERNIGHT. A FEW MODELS ARE HINTING AT THE  
POTENTIAL FOR FOG DEVELOPMENT TONIGHT. GIVEN HOW DRY THE AIR MASS IS  
EXPECTED TO BE, OPTED TO HOLD OFF ON MENTIONS FOR NOW.  

 
   
MARINE
 
(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)  
ISSUED AT 417 AM EDT THU AUG 22 2019  
 
NORTHERLY WINDS BETWEEN 10 AND 20 KNOTS ARE EXPECTED TODAY. THE  
STRONGEST WINDS ARE EXPECTED TO BE ACROSS THE SOUTH HALF OF THE LAKE  
NEAR THE SHORELINES DURING THE DAY, ESPECIALLY WITH SOME FUNNELING  
INTO THE DULUTH HARBOR AND WHITEFISH BAY IN THE AFTERNOON. HIGH  
PRESSURE THEN TAKES OVER FOR THE END OF THE WEEK INTO THE FIRST  
HALF OF THE WEEKEND, REDUCING WINDS TO SPEEDS BELOW 15 KNOTS.  
TOWARDS THE END OF THE WEEKEND, HIGH PRESSURE MOVES EAST OF THE  
REGION, AND SOUTHERLY FLOW WILL START TO RAMP UP ACROSS THE LAKE,  
WITH WINDS 15 TO 20 KNOTS SATURDAY NIGHT THROUGH MONDAY. LATE IN THE  
DAY MONDAY THROUGH MONDAY NIGHT, SOUTH WINDS OVER THE EAST HALF OF  
THE LAKE COULD GUST UPWARDS OF 30 KNOTS AHEAD OF AN APPROACHING  
FRONT FROM THE WEST.  

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

 
 

 
 
SHORT TERM...RITZMAN  
LONG TERM...ROLFSON  
AVIATION...RITZMAN  
MARINE...RITZMAN  
 
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