971  
FXUS63 KGRR 021936  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
336 PM EDT MON OCT 2 2023  
 
LATEST UPDATE...  
SHORT TERM/LONG TERM/MARINE/CLIMATE  
   
SHORT TERM  
(THIS EVENING THROUGH TUESDAY NIGHT)  
ISSUED AT 335 PM EDT MON OCT 2 2023  
 
NOT MUCH TO TALK ABOUT IN THE SHORT TERM. BIG UPPER RIDGE  
OVERHEAD WITH 588 DAM HEIGHTS CONTINUES TO SUPPORT WELL ABOVE  
NORMAL TEMPS AND MOSTLY CLEAR SKIES. HIGHS ON TUESDAY SHOULD BE A  
COUPLE DEGREES WARMER THAN TODAY AS SOUTHERLY RETURN FLOW  
STRENGTHENS A BIT AND SLIGHTLY DEEPER MIXING OCCURS. MOST  
LOCATIONS FALLING JUST SHY OF RECORDS FOR THE DAY THOUGH (SEE  
CLIMATE SECTION BELOW FOR DETAILS). SOME INCREASE IN HIGH LEVEL  
CLOUDS IS EXPECTED ON TUESDAY NIGHT AS THE UPPER RIDGE AXIS  
SHIFTS EAST.  
 
   
LONG TERM  
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 335 PM EDT MON OCT 2 2023  
 
THERE REMAINS MEDIUM TO GOOD CONFIDENCE IN THE LARGE-SCALE PATTERN  
DRIVING A COOL DOWN THURSDAY THROUGH THE WEEKEND, FOLLOWED BY THE  
START OF A MODERATING TREND NEXT MONDAY. THIS WILL HAPPEN AS A  
CONSEQUENCE OF A ROSSBY WAVE TROUGH IN THE NORTHERN JET STREAM  
AMPLIFYING AS IT SLOWLY PROGRESSES FROM CENTRAL NORTH AMERICA  
MIDWEEK TOWARD THE NORTHEAST BY LATE WEEKEND. SOME NUANCE IN THE  
DETAILS AND A FEW OUTLIER SOLUTIONS FOR TEMPERATURES AND RAIN  
AMOUNTS THIS WEEKEND STILL LINGER.  
 
RAIN SHOWERS ARE LIKELY WEDNESDAY NIGHT INTO THURSDAY, ALONG WITH A  
CHANCE OF THUNDER, AHEAD OF THE FIRST COLD FRONT. THE MOST LIKELY  
RANGE OF RAIN TOTALS FROM THIS RANGES BETWEEN 0.25 AND 0.50 INCH,  
THOUGH TOTALS LEAN CLOSER TO 0.75 INCH IN SOUTHERN MICH. THE  
ENSEMBLE SPREAD IN THE HIGH TEMPS FOR FRIDAY IS RELATIVELY WIDE  
DEPENDENT ON THE TIME OF ARRIVAL OF THE SECOND COLD FRONT, WITH THE  
MIDDLE 50 PERCENT OF ECE MEMBERS RANGING ANYWHERE IN THE 60S (THIS  
IMPLIES AT LEAST SOME CHANCE OF HIGHS IN THE 50S OR 70S ALSO). WHILE  
HIGH TEMPERATURES IN THE 50S WITH LAKE-EFFECT SHOWERS ARE THE MOST  
LIKELY SCENARIO OVER THE WEEKEND, SOME OUTLIER SOLUTIONS IN THE  
EVOLUTION OF THE UPPER-LEVEL WAVE LEAVE THE DOOR OPEN FOR MILDER  
TEMPERATURES IN THE 60S. THERE HAS ALSO BEEN AN INCREASE IN THE  
NUMBER OF MEMBERS AMONG THE EURO, GFS, AND CANADIAN ENSEMBLES  
SHOWING HIGHER-END RAIN AMOUNTS GREATER THAN AN INCH POSSIBLE ON  
SATURDAY, THOUGH THIS IS NOT THE FAVORED OUTCOME AT THIS TIME.  
 
 
   
AVIATION  
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)  
ISSUED AT 128 PM EDT MON OCT 2 2023  
 
HIGH PRESSURE CENTERED JUST EAST OF MICHIGAN WILL PROVIDE  
PREDOMINANTLY CLEAR SKIES WITH WEAK WINDS BETWEEN SE AND SW. ONLY  
CHANCE FOR MVFR TO IFR VISIBILITY LATE TONIGHT WILL COME FROM  
PATCHES OF FOG/MIST, SIMILAR TO LAST NIGHT.  
 
 
   
MARINE  
 
ISSUED AT 335 PM EDT MON OCT 2 2023  
 
SOUTHERLY WINDS WILL BE GRADUALLY RAMPING UP THE NEXT COUPLE  
DAYS, ESPECIALLY NORTH OF HOLLAND. CONDITIONS REMAINING BELOW  
SMALL CRAFT ADVISORY CRITERIA THROUGH TUESDAY NIGHT, BUT A  
HEADLINE MAY BE NEEDED BY WEDNESDAY OVER MAINLY THE NORTHERN  
MARINE ZONES. A MORE ACTIVE PERIOD ON THE LAKE IS EXPECTED FOR THE  
END OF THE WEEK AND NEXT WEEKEND AS COLD AIR/MORE FALL-LIKE  
PATTERN ARRIVES.  
 
 
   
CLIMATE  
 
ISSUED AT 335 PM EDT MON OCT 2 2023  
 
RECORD HIGHS THROUGH WEDNESDAY:  
 
MON TUE WED  
 
GRAND RAPIDS 87 - 1971 85 - 1953,'19,'00 87 - 1951  
MUSKEGON 83 - 1971, '53 83 - 2018 83 - 1951  
LANSING 86 - 1922 90 - 1898 86 - 1951,'00  
KALAMAZOO 89 - 1897 88 - 1953 90 - 1951  
BATTLE CREEK 88 - 1971 88 - 1953 87 - 1951  
JACKSON 87 - 1971 89 - 1953 90 - 1951  
HOLLAND 86 - 1971 86 - 1919 89 - 1951  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
LM...NONE.  
 
 
 
 
SHORT TERM...MEADE  
LONG TERM...CAS  
AVIATION...CAS  
CLIMATE...NJJ  
MARINE...MEADE  
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