941  
FXUS63 KGRR 140719  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
319 AM EDT MON OCT 14 2019  
 
LATEST UPDATE...  
SYNOPSIS/DISCUSSION/MARINE  
   
SYNOPSIS
 
 
ISSUED AT 308 AM EDT MON OCT 14 2019  
 
-AREAS OF FROST TUESDAY MORNING WITH RAIN ARRIVING DURING THE DAY  
 
-BLUSTERY WITH LAKE EFFECT RAIN SHOWERS WEDNESDAY  
 
-DRY PERIOD FROM THURSDAY INTO AT LEAST FRIDAY  
 
-UNSETTLED WEATHER POSSIBLE ESPECIALLY TOWARD THE END OF THE  
WEEKEND INTO EARLY NEXT WEEK  
 

 
   
DISCUSSION
 
(TODAY THROUGH NEXT SUNDAY)  
ISSUED AT 308 AM EDT MON OCT 14 2019  
 
OUR NEXT RISK FOR RAIN WILL ARRIVE ON TUESDAY AS AN AREA OF LOW  
PRESSURE STEADILY DEEPENS AS IT MOVES FROM CENTRAL WI TO LAKE HURON.  
THE MORE FAVORABLE UPPER LEVEL JET DIVERGENCE WILL BE LOCATED ACROSS  
THE U.P. AND NORTHERN LOWER MI WITH THIS SYSTEM. WITH THE H850 LOW  
MOVING ACROSS NORTHERN WI/NORTHERN LOWER MI IT MAKES SENSE THAT THE  
HEAVIER PRECIPITATION WILL BE NORTH OF OUR REGION. THERE IS A SMALL  
WINDOW WHERE WE COULD GET SOME RUMBLES OF THUNDER 18Z TUE THROUGH  
00Z WED AS SHOWN BY PROJECTED MUCAPE BY THE MEDIUM RANGE GUIDANCE.  
OTHERWISE, RAIN SHOWERS CAN BE EXPECTED AT TIMES TUESDAY AFTERNOON  
AND EVENING ESPECIALLY. WRAP-AROUND LAKE EFFECT RAIN SHOWERS AND  
BLUSTERY CONDITIONS ARE EXPECTED WEDNESDAY AS THE LOW DEEPENS INTO  
THE MID 990S OVER LAKE HURON. IN OTHER WORDS, VERY OCTOBER-LIKE.  
 
PRIOR TO THIS SYSTEM'S ARRIVAL, FROST IS LOOKING LIKE A POSSIBILITY  
TUESDAY MORNING AWAY FROM THE LAKESHORE. SOME SUBFREEZING  
TEMPERATURES ARE NOT OUT OF THE QUESTION ACROSS INTERIOR CENTRAL  
LOWER MI. THE NEXT THREAT FOR FROST WOULD OCCUR FRIDAY MORNING.  
 
MEDIUM RANGE DETERMINISTIC GUIDANCE AND RESPECTIVE ENSEMBLE MEMBERS  
(ECM/GEFS/GEPS) SUGGEST A MILD AND WET PATTERN IS POSSIBLE ACROSS  
THE GREAT LAKES TOWARD THE END OF THIS WEEKEND AND INTO EARLY NEXT  
WEEK. TOO SOON TO TALK SPECIFIC AMOUNTS OF RAIN BUT THE UPPER LEVEL  
PATTERN (DEEP SOUTHWEST FLOW WITH AN OPEN FEED OF GULF MOISTURE  
POTENTIALLY) WOULD SUPPORT ANOMALOUSLY HIGH PRECIPITABLE WATER  
VALUES.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)  
ISSUED AT 127 AM EDT MON OCT 14 2019  
 
NO REAL AVIATION HAZARDS EXPECTED FOR THE NEXT 24 HOURS WITH VFR  
HOLDING IN PLACE. NOT IMPOSSIBLE THAT SOME CEILINGS COULD  
OCCASIONALLY COME DOWN TO NEAR 3000 FT AS HAS BEEN OBSERVED ACROSS  
NORTHERN LOWER MICHIGAN, BUT WOULD NOT EXPECT THIS TO BE A  
DOMINANT CONDITION, AND THE MAIN THREAT WOULD BE INTO THE EARLY  
MONDAY MORNING HOURS.  
 

 
   
MARINE
 
 
ISSUED AT 308 AM EDT MON OCT 14 2019  
 
WILL CONTINUE THE SCA AS IS, BUT THERE IS POTENTIAL FOR AN EARLIER  
CANCELLATION DEPENDING ON HOW QUICKLY THE WINDS/WAVES SETTLE DOWN.  
THE REPRIEVE WILL BE BRIEF, HOWEVER, WITH WINDS PICKING UP TUESDAY  
(S/SW FLOW EVENT) AND WAVES REACHING 4 TO 7 FT MAINLY NORTH OF  
GRAND HAVEN. CONDITIONS WORSEN WEDNESDAY (NW FLOW EVENT) WITH  
LAKESHORE-ERODING WAVES OF 7 TO 11 FT ONCE AGAIN BATTERING MUCH  
OF OUR COASTLINE.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR MIZ037>040-  
043>046-050>052-056>059-064>067-071>074.  
 
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR  
LMZ844>849.  
 

 
 

 
 
SYNOPSIS...HOVING  
DISCUSSION...HOVING  
AVIATION...HOVING  
MARINE...HOVING  
 
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