985  
FXUS63 KGRR 290723  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
323 AM EDT THU SEP 29 2016  
 
LATEST UPDATE...  
SYNOPSIS/SHORT TERM/LONG TERM/MARINE  
   
SYNOPSIS
 
 
ISSUED AT 323 AM EDT THU SEP 29 2016  
 
LOW PRESSURE WILL CONTINUE TO SPIN NEAR AND OVER LOWER MICHIGAN  
THROUGH THE WEEK AND INTO THE WEEKEND. THIS WILL BRING MOSTLY  
CLOUDY WEATHER WITH PERIODS OF SHOWERS AND A FEW THUNDERSTORMS.  
 

 
   
SHORT TERM
 
(TODAY THROUGH SATURDAY)  
ISSUED AT 323 AM EDT THU SEP 29 2016  
 
UPPER CUTOFF LOW SPINS ACROSS THE OHIO VALLEY THEN MOVES NORTH  
BACK INTO LOWER MICHIGAN BY THE END OF THE PERIOD. STRONG EASTERLY  
FLOW INCLUDING LOW LEVEL JET WILL TAP INTO TROPICAL MOISTURE  
PLUME MOVING UP THE EAST COAST BY THURSDAY NIGHT. SHOWERS WILL  
BECOME MORE WIDESPREAD AND PERSIST INTO FRIDAY BEFORE BEGINNING TO  
TAPER OFF AS THE OCCLUDED LOW MOVES INTO THE FORECAST AREA.  
 
MARGINALLY STEEP LAPSE RATES LATE THURSDAY INTO SATURDAY MAKE  
DIURNAL ENHANCEMENT OF THUNDERSTORMS POSSIBLE EACH DAY. THE  
PERSISTENT NATURE OF THE FLOW REGIME AND THE PRESENCE OF TROPICAL  
MOISTURE FEEDING IN WILL MEAN THAT EXCESSIVE RAINS ARE POSSIBLE  
AND THIS WILL HAVE TO BE MONITORED CLOSELY.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 323 AM EDT THU SEP 29 2016  
 
THE UPPER LOW WILL CONTINUE TO LINGER OVER OUR REGION SATURDAY NIGHT  
THROUGH SUNDAY AND BRING EXTENSIVE CLOUD COVER AND SCATTERED  
SHOWERS.  
 
THE PATTERN SHOULD FINALLY BECOME MORE PROGRESSIVE SUNDAY NIGHT  
INTO EARLY NEXT WEEK WHEN THE UPPER LEVEL LOW WILL FINALLY  
MOVE EAST OF OUR REGION AS UPPER RIDGING BUILDS IN FROM THE  
WEST.  
 
AS A RESULT FAIR WEATHER WILL FINALLY RETURN EARLY NEXT WEEK  
WITH SEASONABLY MILD TEMPERATURES REACHING THE LOWER TO PERHAPS  
MIDDLE 70'S BY NEXT MON/TUE.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)  
ISSUED AT 1202 AM EDT THU SEP 29 2016  
 
A MIX OF MVFR AND VFR CONDITIONS WILL CONTINUE OVERNIGHT WITH MVFR  
CONDITIONS AT TIMES DUE TO LOW CLOUDS AND SHOWERS. CONDITIONS WILL  
GRADUALLY DETERIORATE TO PRIMARILY MVFR THURSDAY DUE TO LOW CLOUDS  
AND SHOWERS THROUGH THE DAY. NORTHEAST WINDS WILL INCREASE TO  
10-15 KTS WITH GUSTS TO AROUND 20 KTS FROM MID MORNING THROUGH THE  
AFTERNOON. CONDITIONS MAY DETERIORATE FURTHER TO IFR THURSDAY  
EVENING DUE TO LOW CLOUDS/LOWERING CIGS AND SHOWERS.  
 

 
   
MARINE
 
 
ISSUED AT 323 AM EDT THU SEP 29 2016  
 
WINDS AND WAVES WILL CONTINUE TO BE HAZARDOUS TO SMALL CRAFT INTO  
FRIDAY. STRONG OFFSHORE WINDS WITH GUSTS OVER 25 KNOTS CAN BE  
EXPECTED. WAVE HEIGHTS WILL BE GREATEST FURTHER FROM SHORE IN THE  
EASTERLY FLOW.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 140 PM EDT TUE SEP 27 2016  
 
RIVER LEVELS ARE AROUND NORMAL FOR THIS TIME OF YEAR. LAKE ENHANCED  
RAIN SHOWERS ARE POSSIBLE THROUGH WEDNESDAY. RAIN SHOWERS CONTINUE  
TO BE POSSIBLE INTO SUNDAY. RAINFALL TOTALS INTO THE WEEKEND WILL  
RANGE FROM A HALF INCH UP TO AN INCH AND A HALF. RIVERS AND STREAMS  
SHOULD REMAIN BELOW BANKFULL THROUGH THE WEEKEND.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR LMZ844>849.  
 

 
 

 
 
SYNOPSIS...OSTUNO  
SHORT TERM...OSTUNO  
LONG TERM...LAURENS  
AVIATION...LAURENS  
HYDROLOGY...63  
MARINE...OSTUNO  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MI Page
The Nexlab IN Page Main Text Page