Area Forecast Discussion


809 
FXUS63 KGRR 130717
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
318 AM EDT TUE AUG 13 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 318 AM EDT TUE AUG 13 2013
COOL CANADIAN HIGH PRESSURE IS BUILDING INTO LOWER MICHIGAN AND WILL 
SERVE UP A COUPLE OF DAYS WITH HIGHS NEAR 70. AFTER THAT A WARMUP 
WILL CONTINUE INTO THE WEEKEND WHERE WE/LL SEE NEAR NORMAL HIGHS IN 
THE LOWER 80S. A DRY PATTERN IS DEVELOPING AND VERY LITTLE IF ANY 
RAINFALL IS EXPECTED FOR THE NEXT SEVERAL DAYS. 
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 318 AM EDT TUE AUG 13 2013
FORECAST CONCERNS ARE MINIMAL THIS MORNING. LITTLE CHANGE TO THE 
GRIDS WERE NEEDED. 
A COLD FRONT HAS MOVED THROUGH THE CWA AND SFC DEWPOINTS ARE FALLING 
RAPIDLY FROM THE MID 60S ACROSS THE SRN CWA TO MID 40S IN THE NRN 
CWA. LATEST IR LOOP SHOWS SOME STRATOCU MOVING SOUTH ACROSS NRN LWR. 
THIS SHOULD CLIP THE NE CWA AND WE BOOSTED THE CLOUD GRIDS AS A 
RESULT.
WATER VAPOR LOOP SHOWS A SHORT WAVE DROPPING SOUTH OVER FAR WRN 
ONTARIO. THIS WILL CONTINUE TO MOVE SEWD AND CLIP THE NE CWA TODAY. 
AS A RESULT WE/LL RUN WITH ISOLD SHOWERS ACROSS THE NE CWA. STEEP 
LOW LEVEL LAPSE RATES WILL MAKE UP FOR SOME OF THE DRY AIR NOTED IN 
FORECAST SOUNDINGS. BUT THERE IS QUITE A BIT OF DRY AIR AND SO NOT 
MUCH IN THE WAY OF PCPN IS ANTICIPATED. 
AS HIGH PRESSURE SETTLES IN AND WINDS DECREASE... A COOL NIGHT IS 
EXPECTED TONIGHT WITH LOWS IN THE 40S ACROSS MUCH OF THE CWA. 
WOULDN/T BE SURPRISED TO SEE A FEW 30S EITHER ESPECIALLY IN LOW 
LYING AREAS. 
FAIR WX IS EXPECTED FOR THE REMAINDER OF THE SHORT TERM. ANOTHER 
COOL DAY IS EXPECTED WEDNESDAY WITH HIGHS AROUND 70 BEFORE THE 
WARMUP BEGINS THURSDAY WITH HIGHS IN THE MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 318 AM EDT TUE AUG 13 2013
SURFACE HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER THROUGH 
MONDAY.  AS A RESULT THE CHANCES FOR WILL RAIN REMAIN RELATIVELY 
LOW.  ALOFT THERE IS SOMEWHAT OF A CYCLONIC FLOW OVER THE 
WEEKEND...LITTLE IF ANY MOISTURE WILL EXIST. ON MONDAY SOME RETURN 
OF 850 MB MOISTURE IS SHOWN ALONG WITH AFTERNOON INSTABILITY.  
SOUNDINGS FROM THE 00Z GFS AND 12Z HIGH RES EURO ARE NOT SUPPORTIVE 
OF RAIN GIVEN THE LIMITED PROFILE MOISTURE AND VERY THIN CAPE.  AS A 
RESULT..I AM NOT CONFIDENT ENOUGH TO ADD PRECIPITATION TO THE 
FORECAST AT THIS TIME.
ALONG WITH THE RETURNING MOISTURE WILL BE MODERATING TEMPERATURES 
EARLY NEXT WEEK.  SO AFTER A COOLER THAN NORMAL END OF THE WEEK...WE 
MAY START TO SEE ABOVE NORMAL TEMPS BY MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1136 PM EDT MON AUG 12 2013
FOG HAS DEVELOPED IN THE AREA OF CALM WINDS JUST AHEAD OF THE COLD
FRONT IN THE I-94 TAF SITE GROUP AS OF 03Z. THIS FOG SHOULD BE
LIFTED BY THE TIME THE 06Z TAFS ARE ISSUED. WHAT CLEARS THIS OUT
IS THE PASSAGE OF THE COLD FRONT. NORTHWEST WINDS WILL INCREASE
IN SPEED BY 06Z BEHIND THE COLD FRONT TO MIX THE FOG OUT. 
THERE IS A LARGE AREA OF MVFR CIGS OVER NORTHERN LOWER MICHIGAN
MOVING SOUTH WITH THE COLDER AIR. THIS SHOULD OVERSPREAD THE TAF
SITES BY 09Z OR SO ONLY TO MIX OUT BY 14Z. MVFR TO EVEN IFR CIGS
ARE POSSIBLE TOWARD SUNRISE TUESDAY MORNING. DURING TUESDAY
AFTERNOON EXPECT GUSTY NORTH WINDS WITH CUMULUS CLOUDS AS THE
COLD AIR CONTINUES TO COME IN TUESDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 318 AM EDT TUE AUG 13 2013
NORTHWEST WINDS ARE ALREADY GUSTING TO 25KTS AT THE BUOYS AND WAVES 
ARE BEGINNING TO RAMP UP. WE SHOULD GET CLOSE TO 30KTS TODAY. NO 
ADJUSTMENTS TO THE SCA NOR BHS ARE NEEDED THIS MORNING. 
NORTHWEST FLOW WILL MOSTLY AFFECT NORTH FACING BREAKWALLS AND PIERS 
TODAY VIA LONGSHORE/STRUCTURAL/RIP CURRENTS. 
&&
.HYDROLOGY...
ISSUED AT 318 AM EDT TUE AUG 13 2013
A DRY PATTERN IS DEVELOPING WHICH WILL ALLOW RIVERS AND STREAMS 
ACROSS THE SRN CWA TO SLOWLY FALL WITH TIME. ISOLATED SHOWERS ARE 
POSSIBLE ACROSS THE NE CWA BUT QPF IS LESS THAN A TENTH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM 7 AM EDT THIS MORNING THROUGH THIS 
     EVENING FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR LMZ848-849.
     SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 5 AM EDT 
     WEDNESDAY FOR LMZ844>847.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...93
MARINE...93