613  
FXUS63 KGRR 241135  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
735 AM EDT FRI OCT 24 2014  
 
LATEST UPDATE...  
AVIATION  
   
SYNOPSIS
 
 
ISSUED AT 330 AM EDT FRI OCT 24 2014  
 
FAIRLY BENIGN WEATHER WILL CONTINUE THROUGH THE WEEKEND WITH DRY  
WEATHER CURRENTLY FORECAST THROUGH SUNDAY. A COLD FRONT WILL SWEEP  
THROUGH THE REGION SATURDAY MORNING...BUT IT SHOULD PASS THROUGH  
DRY. HIGH TEMPERATURES FRIDAY THROUGH SUNDAY WILL BE SLIGHTLY ABOVE  
NORMAL TOPPING OUT AROUND 60 DEGREES EACH DAY. NORMAL HIGHS FOR THIS  
TIME OF YEAR ARE IN THE MIDDLE TO UPPER 50S. A LOW PRESSURE SYSTEM  
MOVING THROUGH THE GREAT LAKES EARLY NEXT WEEK WILL BRING CHANCES  
FOR SHOWERS AND THUNDERSTORMS ALONG WITH WARM AIR. HIGHS MONDAY AND  
TUESDAY WILL PUSH TOWARDS 70 DEGREES...ESPECIALLY ACROSS SOUTHERN  
LOWER MICHIGAN.  
 

 
   
SHORT TERM
 
(TODAY THROUGH SUNDAY)  
ISSUED AT 330 AM EDT FRI OCT 24 2014  
 
NO REAL CONCERNS IN THE SHORT TERM WITH DRY WEATHER FORECAST THROUGH  
THE PERIOD. THE MAIN ISSUE WILL BE CLOUDS.  
 
WIDESPREAD STRATUS AND STRATOCUMULUS LOCATED UPSTREAM WILL MOVE INTO  
LOWER MICHIGAN TODAY AND SHOULD PROVIDE A MOSTLY CLOUDY DAY. THERE  
IS SOME INDICATION THAT THE CLOUDS MAY BE TRYING TO EXIT THE EASTERN  
CWA LATE IN THE DAY WITH CLEARING IN THE WEST...BUT THINKING WE WILL  
LIKELY HANG ON TO CLOUDS MUCH OF THE DAY.  
 
CLEARING WILL OCCUR TONIGHT FOR A TIME...BEFORE MOISTURE STREAMS  
BACK IN AHEAD OF THE COLD FRONT APPROACHING FROM THE WEST. SO...IN  
GENERAL A PARTLY CLOUDY NIGHT...BUT WE SHOULD TURN MOSTLY CLOUDY IN  
MOST AREAS BY DAYBREAK SATURDAY.  
 
THE FRONT ON SATURDAY STILL LOOKS TO TRAVERSE THE AREA DRY. MOISTURE  
IS NOT ALL THAT IMPRESSIVE IN THE 1000-700MB LAYER AND MOST OF THE  
DYNAMICS REMAIN TO THE NORTH. THE ASSOCIATED UPPER WAVE IS LOCATED  
IN THE NORTHERN GREAT LAKES WITH LITTLE IF ANY VERTICAL MOTION DOWN  
OUR WAY. CLOUDS SHOULD BE THE MAIN IMPACT WITH THIS SYSTEM.  
 
THE CLOUDS WILL EXIT THE EAST SATURDAY AFTERNOON...WITH CLEARING  
TAKING PLACE FROM WEST TO EAST THROUGH THE DAY. HIGH PRESSURE  
SETTLES INTO THE AREA FOR SATURDAY NIGHT AND SUNDAY WITH MOSTLY  
CLEAR SKIES.  
   
LONG TERM
 
(SUNDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 330 AM EDT FRI OCT 24 2014  
 
THE MODELS HAVE TRENDED INTO VERY GOOD AGREEMENT THROUGH MUCH OF THE  
LONG TERM PERIOD. MUCH WARMER AIR ARRIVES AT THE BEGINNING OF THE  
LONG TERM AS A LONG WAVE UPPER TROUGH DEVELOPS OVER THE ROCKIES.  
THIS PUMPS THE WARMER AND MORE MOIST AIR INTO THE REGION. A WARM  
FRONT SHOULD COME THROUGH MONDAY MORNING. ALL THE MODELS SHOW SOME  
CONVECTION NORTH OF THE FRONT LATE SUNDAY NIGHT INTO MONDAY ALONG  
AND NORTH OF I-96. I INCREASED POPS SLIGHTLY OVER THE NORTHERN CWA  
WITH THIS FRONT. BY MONDAY AFTERNOON H8 TEMPS SURGE TO +14C WHICH  
SHOULD SUPPORT MAX TEMPS OF 65 TO 70 ACROSS MUCH OF THE CWA...  
POSSIBLY HIGHER...DEPENDENT ON IF ANY SUN COMES THROUGH BEHIND THE  
FRONT.  
 
THE MODELS HAVE TRENDED QUICKER WITH A COLD FRONT THAT APPEARS TO  
COME THROUGH TUESDAY MORNING NOW. WE SHOULD SEE A LINE OF SHOWERS  
AND A FEW THUNDERSTORMS WITH IT. THEN...IF THE TIMING VERIFIES WE  
SHOULD SEE FALLING TEMPS TUESDAY AFTERNOON AS H8 TEMPS CRASH. IN  
FACT THE MODELS HAVE ALSO TRENDED COLDER BEHIND THIS FRONT WITH H8  
TEMPS PLUNGING TO AROUND -1C BY TUESDAY NIGHT. HAVE LOW POPS FOR  
TUESDAY NIGHT...BUT IF THE COLDER TREND CONTINUES WE MAY NEED TO  
INCREASE POPS AS SOME LAKE EFFECT SHOWERS COULD BE POSSIBLE THEN.  
 
THE MID WEEK PERIOD LOOKS MAINLY DRY AND SEASONABLY COOL AS THE LONG  
WAVE UPPER TROUGH EXITS AND ZONAL FLOW DEVELOPS.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)  
ISSUED AT 735 AM EDT FRI OCT 24 2014  
 
MAIN AVIATION CONCERN THE NEXT 24 HOURS IS MVFR  
CONDITIONS...MAINLY FROM CEILINGS TODAY AND AGAIN LATE TONIGHT.  
POOR AVIATION CONDITIONS ARE CURRENTLY LOCATED UPSTREAM ACROSS  
WISCONSIN AND THEY WILL TRY TO MOVE INTO THE LOWER PENINSULA  
TODAY. NOT EXPECTING IFR AT THIS POINT...BUT MVFR CONDITIONS ARE  
LIKELY FOR KAZO...KGRR AND KMKG. TO THE EAST...AT KLAN AND KJXN  
NOT THINKING THE LOWER CEILINGS WILL MAKE IT THAT FAR EAST AND  
KEPT THEM VFR. THE CLOUDS SHOULD SCATTER OUT FROM WEST TO EAST  
THIS EVENING...FROM 20Z TO 00Z. MAINLY CLEAR SKIES ARE EXPECTED  
FOR A TIME AFTER 00Z...WITH MVFR CEILINGS SPREADING BACK IN LATE  
TONIGHT...AFTER 09Z OR SO. WINDS WILL GENERALLY BE SOUTHWEST AT 5  
TO 10 KNOTS.  
 

 
   
MARINE
 
 
ISSUED AT 330 AM EDT FRI OCT 24 2014  
 
LIGHT SOUTHERLY FLOW TODAY WILL KEEP WAVE HEIGHTS IN CHECK. SOUTH  
WINDS BEGIN TO INCREASE TONIGHT AHEAD OF A COLD FRONT BUT SHOULD  
STAY JUST BELOW SMALL CRAFT ADVISORY CRITERIA. THE NEXT TIME FRAME  
OF CONCERN WILL BE SATURDAY BEHIND A COLD FRONT WHERE WEST AND  
NORTHWEST WINDS WILL LIKELY RAMP INTO THE 15 TO 25 KNOT RANGE. WAVES  
SHOULD BUILD INTO THE 3 TO 6 FOOT RANGE. AT THIS POINT WILL HOLD OFF  
ON A PERIOD 3 SMALL CRAFT ADVISORY. ONE WILL LIKELY BE NEED THOUGH.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 330 AM EDT FRI OCT 24 2014  
 
HYDRO CONCERNS ARE LIMITED THROUGH THIS WEEKEND WITH LOW RIVER  
LEVELS AND NO PRECIPITATION FORECAST. THE NEXT CHANCE FOR SOLID RAIN  
COMES SUNDAY NIGHT INTO EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM  
TRAVERSES THE AREA. PWAT VALUES INCREASE TO AROUND 1.25 INCHES WHICH  
IS ABOVE THE 75 PERCENTILE FOR THIS TIME OF YEAR. THE AMOUNT OF RAIN  
EXPECTED THOUGH SHOULD BE ABLE TO BE ABSORBED WITHOUT ISSUE GIVEN  
LOW FLOWS.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LM...NONE.  

 
 

 
 
SYNOPSIS...DUKE  
SHORT TERM...DUKE  
LONG TERM...JK  
AVIATION...DUKE  
HYDROLOGY...DUKE  
MARINE...DUKE  
 
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