978  
FXUS63 KGRR 281144  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
744 AM EDT MON JUL 28 2014  
 
LATEST UPDATE...  
AVIATION  
   
SYNOPSIS
 
 
ISSUED AT 327 AM EDT MON JUL 28 2014  
 
COOLER AND DRIER AIR IS FLOWING SOUTH FROM CANADA. HIGH TEMPERATURES  
WILL STRUGGLE TO REACH 70 TODAY. GENERALLY DRY WEATHER IS EXPECTED  
TODAY. BY TUESDAY...SHOWERS AND THUNDERSTORMS ARE POSSIBLE  
ESPECIALLY DURING THE AFTERNOON. A FEW OF THE STORMS COULD PRODUCE  
SOME SOME SMALL HAIL. A SLOW WARMING TREND WILL TAKE HIGHS TO THE  
UPPER 70S BY THE END OF THE WEEK...WHICH IS STILL WELL BELOW NORMAL.  
 

 
   
SHORT TERM
 
(TODAY THROUGH WEDNESDAY)  
ISSUED AT 327 AM EDT MON JUL 28 2014  
 
FORECAST CONCERNS DEAL WITH THE CONVECTIVE POTENTIAL TUESDAY. SFC  
HIGH PRESSURE WILL MOVE OVER THE GREAT LAKES TUESDAY. THAT WILL  
LIKELY GIVE US SOME SUNSHINE. AT THE SAME TIME MUCH COOLER AIR  
ALOFT...H5 TEMPS FALLING TO -17C WILL CREATE STEEP LAPSE RATES. LI'S  
NEAR -1C AND MUCAPE AROUND 700 J/KG COUPLED WITH THE COMBINATION OF  
THE HEATING AND INSTABILITY ALOFT WILL PROBABLY RESULT IN  
THUNDERSTORM DEVELOPMENT...ESPECIALLY DURING THE AFTERNOON. AND SOME  
OF THE STORMS THAT DEVELOP WILL PROBABLY PRODUCE SOME SMALL HAIL.  
 
COOL TEMPS ALOFT ON WEDNESDAY MAY RESULT IN SOME SHRA/TSRA  
DEVELOPMENT TOO. HOWEVER THE DYNAMICS WEDNESDAY ARE NOT AS STRONG AS  
TUESDAY SO OUR POPS ARE LOWER.  
 
FOR TODAY WE/LL SEE SOME SUNSHINE. RADAR TRENDS CONTINUE TO SHOW A  
DECREASE IN SHOWER ACTIVITY AND DRY WX IS EXPECTED BY 12Z. LATEST IR  
LOOP SHOWS CLOUDS DISSIPATING FROM NORTH TO SOUTH AND SO WE EXPECT  
SOME SUNSHINE TODAY. VERY COOL WEATHER FOR LATE JULY THOUGH WITH  
HIGHS AROUND 70.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH SUNDAY)  
ISSUED AT 327 AM EDT MON JUL 28 2014  
 
NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST THIS MORNING AS IT  
STILL LOOKS ON TRACK. 00Z MODEL RUNS CONTINUE THE THEME OF UPPER  
TROUGHING THROUGH THE LONG TERM. TOWARDS THE END OF THE WEEK AND  
INTO NEXT WEEKEND THE UPPER TROUGH IS BEGINNING TO LIFT OUT TO THE  
NORTHEAST ACROSS CANADA...BUT THERE IS STILL SOME TROUGHING THAT  
PERSISTS. AT THE SURFACE FEATURES REMAIN RELATIVELY WEAK...THERE  
ISN/T MUCH TO KEY ON. EXPECT SOME WEAK TROUGHS TO MOVE THROUGH  
ASSOCIATED WITH MID LEVEL SHORTWAVES PIVOTING AROUND THE UPPER LOW.  
 
EXPECT SOME DIURNAL SHOWERS AND A FEW STORMS EACH AFTERNOON AND  
EVENING AROUND THE TIME OF MAX HEATING. HAVE POPS NEAR 30 PCT EACH  
DAY DURING THE THURS-SAT TIME FRAME. HAVE SUNDAY DRY AT THIS POINT  
BUT IT MAY BE ANOTHER DAY WITH SOME DIURNAL PRECIP AS WELL.  
 
HIGH TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW NORMAL THROUGH THE  
PERIOD. EXPECTING HIGHS IN THE UPPER 70S TO AROUND 80 EACH DAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 744 AM EDT MON JUL 28 2014  
 
SOME MVFR CLOUDS WILL LINGER ACROSS THE AREA THROUGH 15Z OR  
SO...WITH VFR CONDITIONS EXPECTED THERE AFTER. CEILINGS IN THE  
1000-3000FT RANGE THIS MORNING SHOULD LIFT INTO THE 3500-5000FT  
RANGE FOR THIS AFTERNOON. TONIGHT...BROKEN CEILINGS AROUND 5000FT  
ARE EXPECTED TO SWEEP THROUGH THE AREA FROM OF THE NORTH.  
CONDITIONS WILL BE RELATIVELY DRY TODAY WITH A GUSTY NORTH-  
NORTHWEST WIND OF 10-22 KNOTS. WINDS WILL TURN LIGHT TONIGHT.  
 

 
   
MARINE
 
 
ISSUED AT 327 AM EDT MON JUL 28 2014  
 
NO CHANGES TO THE MARINE HEADLINES. SCA AND BEACH HAZARDS STATEMENT  
REMAIN IN EFFECT. NORTH WINDS 15 TO 25 KNOTS WITH GUSTS TO 30 KNOTS  
ARE EXPECTED. HIGHEST WAVES WILL BE IN THE SOUTHERN NEARSHORE ZONES  
IN THE 5 TO 8 FOOT RANGE. HAZARDOUS SWIMMING CONDITIONS EXPECTED  
TODAY.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 314 PM EDT SUN JUL 27 2014  
 
STORMS SHOULD KEEP MOVING ALONG THIS EVENING...SO WIDESPREAD HEAVY  
BASIN RAINFALLS ARE NOT EXPECTED. LOCAL DOWNPOURS COULD LEAD TO  
MORE THAN AN INCH OF RAIN IN AN HOURS TIME. THUS THE MAIN HYDRO  
RISK FROM THIS SITUATION WILL BE URBAN AND POOR DRAINAGE FLOODING  
THIS EVENING.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ037-043-050-  
056-064-071.  
 
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR LMZ844>849.  
 

 
 

 
 
SYNOPSIS...93  
SHORT TERM...93  
LONG TERM...DUKE  
AVIATION...DUKE  
HYDROLOGY...MJS  
MARINE...93  
 
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