748  
FXUS63 KMQT 192010  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
310 PM EST WED FEB 19 2020  
   
SHORT TERM
 
(THIS EVENING THROUGH THURSDAY)  
ISSUED AT 252 PM EST WED FEB 19 2020  
 
UPPER MICHIGAN REMAINS UNDERNEATH BROAD TROUGHING THIS AFTERNOON  
WITH PREDOMINANTLY NW FLOW IN THE LOW TO MID LEVELS BACKING TO W  
ALOFT AS CAA CONTINUES. IN THE ABSENCE OF DEEPER FORCING OR  
MOISTURE, INVERSION HEIGHTS HAVE COME DOWN TO ABOUT 4-5 KFT PER NAM,  
NAM HI-RES, GFS SOUNDINGS. MODEL SOUNDINGS SHOW MOISTURE DEEPENING  
AGAIN BRIEFLY THIS EVENING ABOUT 00Z-06Z AS ANOTHER SHORT WAVE,  
THOUGH MUCH WEAKER THAN LAST NIGHT'S, DROPS SOUTHEASTWARD ACROSS  
LAKE SUPERIOR. STILL, THIS ADDITIONAL MOISTURE AND LIFT SHOULD GIVE  
A BOOST TO THE LES BANDS THIS EVENING. WENT WITH THE HI-RES MODELS  
FOR POPS AND LEANING TOWARDS THE CONSSHORT FOR QPF, AND ASSUMED SLRS  
REMAINING AROUND 20:1 (WHICH WORKED WELL YESTERDAY BASED ON THIS  
MORNING'S COOP REPORTS). THE RESULT IS ANOTHER 2-4" IN THE AREA EAST  
OF SHINGLETON AND MELSTRAND OVER TO GRAND MARAIS AND CRISP POINT,  
AND NORTH OF NEWBERRY, WITH UP TO 2" POSSIBLE IN THE PARTS OF THE  
ADVISORY AREA THAT ARE OUTSIDE OF THAT AREA. THEREFORE, WILL EXTEND  
THE WINTER WEATHER ADVISORY FOR THE EASTERN HALF OF THE NW WIND SNOW  
BELTS UNTIL 09Z. SOME LIGHT LES WILL CONTINUE AFTER 09Z UNTIL ABOUT  
15Z OR SO BUT AS INVERSION HEIGHTS DROP AND THE LOW LEVELS BEGIN TO  
DRY OUT MORE THE SNOW WILL BECOME LIGHT ENOUGH THAT IT WON'T NEED  
THE HEADLINE AT THAT POINT.  
 
THE OTHER AREA TO WATCH WILL BE THE KEWEENAW AND WESTERN HALF OF THE  
W WIND SNOW BELTS. THERE MAY BE A STRONGER CONVERGENCE BAND SETTING  
UP IN THIS AREA AS THE W OR SLIGHT S OF W FLOW INTERIOR MEETS THE  
WNW FLOW OVER THE KEWEENAW. WENT ABOUT 0.01-0.03" HIGHER IN QPF THAN  
ANY MODEL BLEND IN THAT AREA BUT THAT STILL ONLY GIVES 1-2" OF NEW  
SNOW TONIGHT. CAN'T REALLY JUSTIFY GOING ANY HIGHER THAN THAT GIVEN  
HOW FAR OUTSIDE OF THE GUIDANCE ENVELOPE IT WOULD BE BUT AT THE SAME  
TIME IT WOULDN'T SHOCK ME IF SOMEONE FROM PAINESDALE TO ONTONAGON  
ENDS UP WITH A FEW INCHES OF MORE SNOW OVERNIGHT.  
 
THE OTHER STORY THIS SHORT-TERM PERIOD WILL BE THE COLD TONIGHT INTO  
TOMORROW MORNING. AS HIGH PRESSURE SETTLES SOUTH INTO THE  
MISSISSIPPI VALLEY AND SKIES CONTINUE TO CLEAR OUTSIDE OF THE LAKE-  
EFFECT BELTS, SHOULD SEE TEMPS DROP OFF QUICKLY OVERNIGHT. THE BIAS-  
CORRECTED GUIDANCE ALL HAS A STRONG SIGNAL FOR SUBZERO LOWS SO WENT  
WITH THE 25TH PERCENTILE OF GUIDANCE, THEN ADJUSTED BACK UPWARDS  
TOWARDS THE WARMER CONSRAW WHERE CLOUD COVER WILL PERSIST. LOWS  
SHOULD FALL TO ABOUT -15 TO -20 IN THE VERY COLDEST SPOTS OF GOGEBIC  
COUNTY NEAR THE WISCONSIN LINE, -5 TO -15 OVER THE REST OF THE  
WESTERN HALF OF THE INTERIOR, AND AROUND 0 OVER THE KEWEENAW, EAST,  
AND ALONG THE LAKE SUPERIOR SHORELINE. WITH THE CENTER OF THE HIGH  
WELL TO THE SOUTH, THERE WILL BE SOME PRESSURE GRADIENT REMAINING -  
ENOUGH TO MAINTAIN ABOUT 3-5 KTS OF WIND THROUGH THE NIGHT. THIS  
COULD BE ENOUGH TO GET WIND CHILLS DOWN INTO ADVISORY-CRITERIA OVER  
GOGEBIC COUNTY TONIGHT BUT GIVEN HOW MARGINAL IT LOOKS AND HOW THE  
COLDEST TEMPS AND STRONGER BREEZES RARELY OCCUR CONCURRENTLY, WILL  
HOLD OFF ON ANY WIND CHILL ADVISORY. SUNNY SKIES TOMORROW SHOULD  
HELP PUSH TEMPS BACK TOWARDS THE UPPER TEENS TO LOW 20S BY TOMORROW  
AFTERNOON. WITH A BREEZY SW WIND DEVELOPING IN THE AFTERNOON IT MAY  
STILL FEEL CHILLY DESPITE THE SUNSHINE.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 129 PM EST WED FEB 19 2020  
 
UPPER AIR PATTERN WILL CONSIST OF A 500 MB RIDGE ACROSS THE ROCKIES  
WITH A TROUGH OFF THE WEST COAST AND ANOTHER IN THE ERN U.S. 00Z  
FRI. THE RIDGE GETS FLATTENED A BIT 00Z SAT OVER THE ROCKIES AND  
THEN MOVES OUT INTO THE PLAINS 00Z SUN AS A TROUGH MOVES INTO THE  
WESTERN U.S. QUIET WEATHER WILL CONTINUE FOR THIS FORECAST PERIOD.  
 
IN THE EXTENDED, THE GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE  
SOUTHERN ROCKIES WITH A SHORTWAVE OVER THE CANADIAN PRAIRIES 12Z  
SUN. THE NORTHERN SHORTWAVE MOVES INTO THE UPPER GREAT LAKES REGION  
12Z MON WITH THE SOUTHERN ONE MOVING INTO THE SOUTHERN MISSISSIPPI  
RIVER VALLEY. MORE ENERGY MOVES INTO THE ROCKIES 12Z TUE WHICH DIGS  
OUT AN AMPLIFIED TROUGH OVER THE ROCKIES. THIS AMPLIFIED TROUGH  
MOVES INTO THE CENTRAL U.S. 12Z WED. ABOVE NORMAL TEMPERATURES WILL  
COOL TO NEAR NORMAL FOR THIS FORECAST PERIOD. STORMY PATTERN WILL  
CONTINUE WELL TO THE SOUTH OF THE AREA.  

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)  
ISSUED AT 1231 PM EST WED FEB 19 2020  
 
LAKE-EFFECT CLOUDS CONTINUE AT THE TERMINALS THIS AFTERNOON WITH  
PERIODS OF MODERATE TO HEAVY LAKE-EFFECT SNOW AT CMX AS WELL.  
HOWEVER IWD IS RIGHT ON THE EDGE OF THE CLOUD SHIELD AND SAW HAS  
BEEN OSCILLATING BETWEEN VFR AND MVFR WITH INDICATIONS ON SATELLITE  
THAT THE CIG IS STARTING TO BREAK UP. SO CONDITIONS WILL BE  
IMPROVING TO VFR THROUGH THE AFTERNOON AT THOSE TWO SITES. CMX  
SHOULD HOPEFULLY SEE A MINOR IMPROVEMENT TO IFR VIS LATE AFTERNOON  
BEFORE LAKE-EFFECT SNOW BANDS RESTRENGTHEN THIS EVENING. MORE LIFR  
VIS IS POSSIBLE WHEN THIS HAPPENS BUT SINCE THEY COULD WOBBLE BACK  
AND FORTH HAVE JUST GONE WITH LOWER-END IFR AND TEMPO LIFR FOR THAT  
PERIOD. CONDITIONS BEGIN TO IMPROVE AT CMX AFTER MIDNIGHT BUT EXPECT  
THE MVFR CIG WILL HOLD ON THROUGH THE END OF THE TAF PERIOD.  

 
   
MARINE
 
(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)  
ISSUED AT 310 PM EST WED FEB 19 2020  
 
STIFF NW WINDS 25-30 KTS CONTINUE TONIGHT BEFORE BACKING TO W  
THURSDAY MORNING. WSW GALES TO 40 KTS DEVELOP ON THE WESTERN HALF OF  
THE LAKE THURSDAY AFTERNOON THROUGH FRIDAY MORNING. WINDS RELAX TO  
20 KTS BY SATURDAY MORNING WITH NO OTHER PERIOD OF STRONG WINDS  
ANTICIPATED THROUGH AT LEAST THE BEGINNING OF NEXT WEEK. HEAVY  
FREEZING SPRAY WILL REMAIN A CONCERN THROUGH THURSDAY AFTERNOON AS  
WELL.  

 
   
MQT WATCHES/WARNINGS/ADVISORIES
 
 
UPPER MICHIGAN...  
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR MIZ006-007-  
085.  
 
LAKE SUPERIOR...  
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY  
FOR LSZ162-240>251-263>267.  
 
GALE WARNING FROM 1 PM EST /NOON CST/ THURSDAY TO 4 AM EST /3 AM  
CST/ FRIDAY FOR LSZ162-240>244-249-250-263-264-266.  
 
LAKE MICHIGAN...  
NONE.  

 
 

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