760  
FXUS63 KGRR 240730  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
330 AM EDT SAT JUN 24 2017  
 
LATEST UPDATE...  
SYNOPSIS/SHORT TERM/LONG TERM/MARINE  
   
SYNOPSIS
 
 
ISSUED AT 330 AM EDT SAT JUN 24 2017  
 
A COOL AIRMASS WILL GRADUALLY CONTINUE TO FILTER INTO THE GREAT  
LAKES REGION OVER THE NEXT FEW DAYS. HIGHS TODAY WILL REACH THE  
LOWER 70S, BE NEAR 70 ON SUNDAY AND TOP OUT IN THE MIDDLE TO UPPER  
60S ON MONDAY. NORMAL HIGHS ARE IN THE LOWER 80S THIS TIME OF YEAR  
SO WE ARE WELL BELOW NORMAL. PARTLY TO OCCASIONALLY MOSTLY CLOUDY  
SKIES CAN BE EXPECTED THE NEXT FEW DAYS WITH ISOLATED SHOWERS. EACH  
AFTERNOON A THUNDERSTORM WILL BE POSSIBLE AS WELL.  
 

 
   
SHORT TERM
 
(TODAY THROUGH MONDAY)  
ISSUED AT 330 AM EDT SAT JUN 24 2017  
 
THIS TIME OF YEAR 850MB TEMPS AT TIMES SURGE PAST +20C, BUT NOT IN  
THE SHORT TERM. 850MB TEMPS ARE IN THE LOWER TEENS C THIS MORNING  
AND WILL CONTINUE TO SLIDE THROUGHOUT THE PERIOD. IT MAY BE OUT OF  
SEASON, BUT THE TALK OF DELTA T'S OVER LAKE MICHIGAN IS ON THE  
DOCKET. THE LAKE IS AROUND +17C RIGHT NOW, SO LAKE CLOUDS ARE  
POSSIBLE AS TEMPS DROP TO +7C, WITH LAKE GENERATED PRECIPITATION  
POSSIBLE AT +4C. WE FALL BELOW +7C THIS EVENING AND TO AROUND +4C ON  
MONDAY.  
 
SO, LAKE GENERATED CLOUDS ARE POSSIBLE TONIGHT THROUGH MONDAY, WITH  
RAIN SHOWERS OFF THE LAKE POSSIBLE ON MONDAY. THE AREA WILL BE IN A  
FALL-LIKE NORTHWEST FLOW WITH PERIODIC SHORTWAVES. THREE DISTINCT  
SHORTWAVES LOOK TO AFFECT THE AREA. ONE TODAY, ANOTHER TONIGHT AND  
YET ANOTHER ON MONDAY.  
 
WE HAVE ISOLATED TO SCATTERED SHOWERS IN THE SHORT TERM (20-40 PCT  
CHANCES FOR PRECIP). DURING THE AFTERNOON HOURS, DIURNAL INSTABILITY  
IS FORECAST TO BUILD INTO THE 600-1200 J/KG RANGE WHICH IS PLENTY  
FOR AN ISOLATED STORM. THUNDER WORDING IS THEREFORE CONFINED TO THE  
AFTERNOON HOURS. NOT EXPECTING SIGNIFICANT PRECIPITATION THIS  
WEEKEND, BUT MONDAY HAS THE POTENTIAL TO END UP BEING A BIT MORE ON  
THE RAINY SIDE AS THE LAKE COMPONENT KICKS IN WITH DELTA T'S AROUND  
13C. GIVEN THAT LEVEL OF INSTABILITY AND THE UPPER TROUGH IN PLACE,  
WATERSPOUTS ARE NOT OUT OF THE QUESTION ON MONDAY WITH ANY OF THE  
DEEPER SHOWERS/STORMS THAT DEVELOP.  
   
LONG TERM
 
(MONDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 330 AM EDT SAT JUN 24 2017  
 
SURFACE HIGH PRESSURE WILL MOVE BY TO THE SOUTH OF MICHIGAN TUESDAY  
INTO WEDNESDAY AND SHOULD RESULT IN DRY WEATHER FOR THE AREA. A LOW  
PRESSURE SYSTEM IS THEN EXPECTED TO PASS TO THE NORTHWEST OF LOWER  
MICHIGAN AND DRAPE A FRONT ACROSS THE REGION. WAVES OF LOW PRESSURE  
WILL THEN TRAIN FROM SOUTHWEST TO NORTHEAST ALONG THE FRONT. IF  
THESE WAVES MOVE ACROSS LOWER MICHIGAN, WE COULD SEE AREAL AND RIVER  
FLOODING BY THE END OF THE WEEK.  
 
TEMPERATURES WILL BE WARMING THROUGH THE LONG TERM. THEY WILL BE  
BELOW NORMAL INTO MID WEEK AND NEAR TO A LITTLE ABOVE NORMAL BY  
FRIDAY. NORMAL HIGHS ARE AROUND 80 DEGREES AND NORMAL LOWS ARE IN  
THE UPPER 50S.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)  
ISSUED AT 150 AM EDT SAT JUN 24 2017  
 
VFR CONDITIONS EXPECTED THROUGH SATURDAY NIGHT. A BRIEF SHOWER IS  
POSSIBLE TOMORROW AFTERNOON, BUT CHANCES TOO LOW TO INCLUDE IN THE  
TAFS. WINDS WILL BECOME LIGHT OVERNIGHT AND PICK BACK UP TOMORROW  
AFTERNOON OUT OF THE WEST. GUSTS TO 25 KTS EXPECTED.  
 

 
   
MARINE
 
 
ISSUED AT 330 AM EDT SAT JUN 24 2017  
 
HAVE MAINTAINED THE SMALL CRAFT ADVISORY AND BEACH HAZARDS STATEMENT  
FOR THE SOUTHERN THREE NEARSHORE ZONES/COUNTIES. ESSENTIALLY THEY  
ARE IN EFFECT FROM GRAND HAVEN SOUTHWARD THROUGH SUNDAY EVENING.  
 
THE WINDS AND WAVES ARE FAIRLY BORDERLINE FOR THIS EVENT HOWEVER  
WITH WESTERLY WINDS OF 15 TO 22 KNOTS MUCH OF THE TIME. THE WAVES  
TODAY ARE FORECAST TO BUILD TO NEAR 4 FEET, BUT IT IS NOT A SLAM  
DUNK. GIVEN WATER TEMPS ARE STILL IN THE 60S AND THERE WILL BE  
CLOUDS AND A FEW SHOWERS, THIS IS NOT A HIGH IMPACT EVENT.  
 
ON SUNDAY, WINDS LOOK JUST A BIT WEAKER, ALTHOUGH WE WILL BE COLD  
AIR ADVECTING, WHICH ALWAYS SEEMS TO OVERPERFORM. SO, LETTING THE  
HEADLINES RIDE FOR SUNDAY AS WELL. 4 TO 5 FOOTERS LOOK POSSIBLE ON  
SUNDAY. SUNDAY WILL BE EVEN COOLER, SO AGAIN IMPACT IS NOT HIGH.  
 
A SIMILAR SETUP APPEARS LIKELY FOR MONDAY, SO THE MARINE HEADLINES  
FOR BOATERS AND SWIMMERS MAY NEED TO BE EXTENDED.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 257 PM EDT FRI JUN 23 2017  
 
MAJOR FLOODING IS EXPECTED ALONG THE CHIPPEWA RIVER IN ISABELLA  
COUNTY AND SHARP RISES ARE ALSO OCCURRING ALONG THE MUSKEGON BASIN  
AND WILL CONTINUE THE NEXT COUPLE DAYS AS THE CREST MOVES DOWN  
THE RIVER. FROM 3 TO 5 INCHES OF RAIN FELL LAST NIGHT COMBINED  
WITH EARLIER HEAVY RAINS.  
 
THE GOOD NEWS IS THAT NO HEAVY RAIN IS EXPECTED THROUGH THE  
MIDDLE OF NEXT WEEK WHICH WILL ALLOW THOSE AREAS THAT ARE FLOODING  
TO RECOVER. THE NEXT CHANCE FOR SIGNIFICANT RAIN WILL BE THURSDAY  
OF NEXT WEEK.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...BEACH HAZARDS STATEMENT THROUGH SUNDAY EVENING FOR MIZ056-064-  
071.  
 
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR LMZ844>846.  
 

 
 

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

The Nexlab MI Page
The Nexlab IN Page Main Text Page