502  
FXUS63 KMQT 211027  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
627 AM EDT MON OCT 21 2019  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 307 AM EDT MON OCT 21 2019  
 
BUSY FORECAST IS BEGINNING AS THE CALM BEFORE THE STORM OCCURS.  
UPPER AIR PATTERN CONSISTS OF A DEEP 500 MB TROUGH IN THE CENTRAL  
U.S. WITH A CLOSED LOW OVER THE CENTRAL PLAINS. THIS CLOSED LOW WILL  
HEAD SLOWLY NORTHEAST INTO THE WESTERN U.P. BY 12Z TUE. NAM BRINGS  
IN SOME DEEPER MOISTURE AND 850-500 MB Q-VECTOR CONVERGENCE THIS  
MORNING WITH A DRY SLOT MOVING IN TONIGHT. ECMWF AND GFS SHOW ABOUT  
THE SAME THING. LOOKS LIKE RAIN WILL SPREAD INTO THE AREA DURING THE  
MORNING WITH A PERIOD OF RAIN IN THE AFTERNOON BEFORE THE DRY SLOT  
MOVES IN BY EVENING AND THE WRAPAROUND PART OF THE STORM COMES IN  
LATE TONIGHT. KEPT SOME THUNDER IN THIS EVENING ACROSS THE FAR  
SOUTHERN CWA IN THE DRY SLOT...OTHERWISE DID NOT MAKE TOO MANY  
CHANGES TO THE GOING FORECAST EXCEPT CONTINUED THE TREND OF DELAYING  
THE POPS MOVING IN FOR THIS MORNING. EVERYTHING STILL LOOKS ON TRACK  
FOR LAKESHORE FLOOD ADVISORY AND WILL BE UPDATING THE STATEMENTS FOR  
THAT.  
   
LONG TERM
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 417 AM EDT MON OCT 21 2019  
 
THE WEATHER IN THE MEDIUM RANGE CONTINUES TO BE FOCUSED ON THE  
STRONG FALL LOW PRESSURE SYSTEM CAUSING WIND AND WATER ISSUES.  
MODELS ARE IN GOOD AGREEMENT IN DEPICTING A SLOWLY FILLING ~986-990  
MB LOW OVER FAR NORTHERN WISCONSIN BY TUESDAY MORNING, WITH THE  
STRONG SURFACE PRESSURE GRADIENT/40+ KT LLJ ORIENTED MORE OR LESS S  
TO N OVER LAKE MICHIGAN, THE EASTERN U.P., AND FAR EASTERN LAKE  
SUPERIOR. DESPITE THIS BEING SOUTHERLY FLOW, THE SYSTEM WILL BE  
WRAPPED UP ENOUGH BY THIS POINT THAT COLDER AIR WILL BE ADVECTING IN  
ALOFT, STEEPENING LAPSE RATES AND AIDING IN THE MIXING OF HIGHER  
GUSTS DOWN TO THE SURFACE. GOING OFF MODEL PROGS OF PRESSURE FALLS  
AND THE IMPLIED ISALLOBARIC RESPONSE, THE STRONGEST WINDS WOULD BE  
TUESDAY MORNING, ABOUT 12Z-15Z. THINK 40-45 KT GUSTS ON LAKE  
MICHIGAN AND THE BAY OF GREEN BAY ARE LIKELY DURING THIS PERIOD,  
WITH 30-40 MPH GUSTS MAKE IT INTO ESCANABA, MANISTIQUE, AND  
SURROUNDING AREAS AS WELL. THIS LONG SOUTHERLY FETCH ALSO MEANS  
LAKESHORE FLOOD CONCERNS CONTINUE. WITH THE WIND AND WAVE DIRECTION  
NOW FROM THE SW, THIS NOT AS MUCH OF A CONCERN FOR THE M-35  
SHORELINE SOUTH OF ESC, BUT IT IS A CONCERN FOR ISQ. CURRENT WAVE  
FORECASTS EXCEED WARNING CRITERIA FOR LAKESHORE FLOOD (12 FEET) SO  
THE POTENTIAL FOR LAKESHORE FLOODING IN ISQ ON TUESDAY IS SOMETHING  
THAT NEEDS TO BE WATCHED CLOSELY.  
 
GUSTY WINDS CONTINUE ON LAND AS  
WELL, ESPECIALLY TUESDAY AFTERNOON AS THE LOW PULLS AWAY TO THE  
NORTH, THOUGH 25-30 MPH SHOULD BE ABOUT AS HIGH AS THEY GET AWAY  
FROM THE IMMEDIATE SHORELINES. THERE WILL ALSO BE NUMEROUS WRAP-  
AROUND SHOWERS AROUND ON TUESDAY, WITH PERHAPS SOME LAKE ENHANCEMENT  
OVER THE EAST (USING A LAKE SURFACE TEMP OF 50 F, WE'D HAVE ABOUT A  
9 C SFC-850 MB DELTA T) AS WELL AS UPSLOPE/LAKE-ENHANCEMENT OVER THE  
WEST AND KEWEENAW. PRECIP AMOUNTS THROUGH WEDNESDAY MORNING  
GENERALLY TOTAL 0.1-0.25", EXCEPT 0.25-0.5" IN THOSE AFOREMENTIONED  
AREAS.  
 
THE LOW CONTINUES TO SLOWLY DRIFT NORTHWARD AWAY FROM US ON  
WEDNESDAY, BUT LEAVE BEHIND PLENTY OF WRAP-AROUND MOISTURE FOR  
CLOUDS AND SCATTERED SHOWERS. WITH FLOW OUT OF THE WEST, WEDNESDAY  
LOOKS LIKE AN ALL-DAY SUPERMARKET DRIZZLE FOR THE HIGHER TERRAIN  
FROM MQT ON WEST WHERE UPSLOPE FLOW WILL BE LAKE-ENHANCED UNDER 850  
MB TEMPS FALLING TO ABOUT -5 C BY LATE AFTERNOON. TEMPS ALOFT DROP  
EVEN MORE WED NIGHT INTO THURSDAY MORNING, SO THIS BECOMES THE  
WINDOW FOR SOME BONA FIDE LAKE-EFFECT RAIN/SNOW. WITH LOWS RIGHT  
AROUND FREEZING OVER THE KEWEENAW, AND IN THE UPPER 20S TO AROUND 30  
OVER THE INTERIOR WEST, THIS WOULD PROBABLY BE SOME LIGHT  
ACCUMULATING SNOW. RIGHT NOW AMOUNTS LOOK LIKE LESS THAN AN INCH,  
BUT AS WE GET CLOSER WE'LL SEE IF ANY OF THE HI-RES GUIDANCE PICKS  
UP ON ANY AREAS OF MORE ENHANCED QPF. THE DEEPER MOISTURE IS PROGGED  
TO EXIT BY ABOUT 15Z-18Z THURSDAY, BRINGING AN END TO LAKE-EFFECT  
PRECIP EXCEPT OVER FAR EASTERN LAKE SUPERIOR.  
 
SURFACE HIGH PRESSURE THEN BUILDS IN TO THE UPPER MISSISSIPPI VALLEY  
LATE THURSDAY, PASSING BY TO OUR SOUTH THROUGH WISCONSIN ON FRIDAY.  
WITH 850 MB TEMPS AT THEIR COLDEST IN THE LONG-TERM, AROUND -8 C,  
AND LIGHT WINDS AND CLEARING SKIES AWAY FROM LAKE SUPERIOR, FRIDAY  
MORING LOOKS QUITE CHILLY. DROPPED MINT'S SEVERAL DEGREES BELOW NBM  
GUIDANCE, RELYING ON MOS AND THE BIAS-CORRECTED CMC WHICH USUALLY  
HANDLES CHILLY MORNING LOWS WELL. THIS GIVES SOME LOW 20S IN THE  
NOTORIOUSLY COLD SPOTS, AND AS WE GET CLOSER, WOULD NOT BE SURPRISED  
TO END UP SEEING TEENS IN A FEW SPOTS. DITTO FOR SATURDAY MORNING.  
THE TRADE-OFF IS THAT, AS OF RIGHT NOW, THE WEEKEND LOOKS MOSTLY DRY.  

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 626 AM EDT MON OCT 21 2019  
 
TRANSIENT UPSLOPE FOG WILL CONTINUE AT CMX THIS MORNING AND  
CONDITIONS WILL BE VLIFR AT TIMES. RAIN MOVES IN BY AFTERNOON AND  
CONDITIONS AT ALL SITES WILL DETERIORATE QUICKLY TO VLIFR AT SAW AND  
CMX AND MVFR AT IWD. WINDS WILL STRENGTHEN, GUSTING TO 25-35KT IN  
THE AFTN, STRONGEST AT KCMX. CONDITIONS WILL BEGIN TO IMPROVE THIS  
EVENING AS THE RAIN MOVES OUT.  

 
   
MARINE
 
(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)  
ISSUED AT 307 AM EDT MON OCT 21 2019  
 
THE 00Z MODEL RUNS CAME IN WITH STRONGER WINDS THAN PREVIOUS  
FORECAST, BUT STILL LOOKS LIKE A STRONG GALE EVENT OUT OF THIS  
INCOMING DEEPENING LOW PRESSURE SYSTEM. THERE WILL BE TWO STRONG  
WIND EVENTS WITH THIS LOW PRESSURE SYSTEM. THE WIND WILL INCREASE  
QUICKLY LATE THIS MORNING AND GO TO A STRONG GALE THIS AFTERNOON AND  
EVENING ON LAKE SUPERIOR. COULD BE A FEW STORM FORCE WIND GUSTS IN  
THE WESTERN PART OF LAKE SUPERIOR WITH THE FUNNELING TAKING PLACE IN  
A NORTHEAST WIND REGIME. AS THE LOW APPROACHES, THE STRONGEST WINDS  
MOVE OUT OVERNIGHT TONIGHT. THE WINDS THEN GET UP CLOSE TO GALE  
FORCE ON TUE INTO WED AS THE LOW MOVES AWAY AND THIS WOULD BE THE  
SECOND STRONG WIND EVENT FOR THIS FORECAST PERIOD. HARD TO SAY RIGHT  
NOW IF GALE FORCE WINDS WILL BE MET WITH THIS SECOND EVENT AS THE  
LOW PRESSURE SYSTEM IS WEAKENING IN THE TUE TO WED TIME FRAME AND IS  
MOVING AWAY FROM THE AREA. WILL KEEP THE GALE WARNINGS GOING.  

 
   
MQT WATCHES/WARNINGS/ADVISORIES
 
 
UPPER MICHIGAN...  
LAKESHORE FLOOD WARNING FROM 5 PM THIS AFTERNOON TO MIDNIGHT EDT  
TONIGHT FOR MIZ001-003.  
 
LAKESHORE FLOOD ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM EDT  
THIS EVENING FOR MIZ013-014.  
 
LAKE SUPERIOR...  
GALE WARNING FROM 2 PM THIS AFTERNOON TO 1 AM EDT TUESDAY FOR  
LSZ263-264-266-267.  
 
GALE WARNING FROM 2 PM THIS AFTERNOON TO MIDNIGHT EDT TONIGHT  
FOR LSZ265.  
 
GALE WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT EDT TONIGHT  
FOR LSZ243>245-249>251.  
 
GALE WARNING FROM 3 PM THIS AFTERNOON TO 11 PM EDT THIS EVENING  
FOR LSZ246>248.  
 
GALE WARNING FROM 10 AM EDT /9 AM CDT/ THIS MORNING TO 10 PM EDT  
/9 PM CDT/ THIS EVENING FOR LSZ162.  
 
LAKE MICHIGAN...  
GALE WARNING FROM NOON TODAY TO 11 PM EDT THIS EVENING FOR  
LMZ221-248-250.  
 

 
 

 
 
SHORT TERM...07  
LONG TERM...RJC  
AVIATION...07  
MARINE...07  
 
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