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000
FXUS63 KGRR 131715
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
115 PM EDT THU JUN 13 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 AM EDT THU JUN 13 2013

LOW PRESSURE THAT PRODUCED THUNDERSTORMS LATE WEDNESDAY WILL
CONTINUE TO MOVE AWAY FROM LOWER MICHIGAN TODAY. A WEAK UPPER LOW
WILL DROP SOUTH AND RESULT IN A LOW CHANCE OF SHOWERS ACROSS MID
MICHIGAN BUT MOST OF THE REGION WILL BE DRY TODAY. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AGAIN SATURDAY AHEAD OF A COLD FRONT
MOVING TOWARD THE WESTERN GREAT LAKES.

&&

.UPDATE...
ISSUED AT 1056 AM EDT THU JUN 13 2013

ADDED MASON COUNTY TO THE BEACH HAZARDS BASED ON THE NORTHERLY
FLOW OVER 15 KNOTS. FEATURED LESS IN THE WAY OF CLOUDS FOR THE
AFTERNOON WESTERN PARTS OF THE FORECAST AREA. FROM FORECAST
SOUNDINGS DIURNAL CU WILL BE FORMING. SOME CAPE NOTED AROUND LAN
UP THROUGH THE FREEZING LEVEL. AS A RESULT I KEPT THE VERY SMALL
CHANCE FOR A SHOWER GOING.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM EDT THU JUN 13 2013

FORECAST CONCERNS DEAL WITH PCPN CHANCES LATER TODAY AND AGAIN
SATURDAY.

RADAR SHOWS LIGHT RAIN FALLING OVER THE CWA BUT THE TREND IS A
DECREASE IN INTENSITY AND AREAL COVERAGE. PCPN SHOULD BE CLOSE TO
ENDING BY 8 AM. THIS MORNING SHOULD BE MOSTLY DRY. HOWEVER...ANOTHER
SHORT WAVE DROPPING SOUTH FROM ONTARIO MAY PRODUCE SOME LIGHT
SHOWERS THIS AFTERNOON ACROSS THE ERN 1/2 OF THE CWA.

AFTER A DRY NIGHT AND FRIDAY THE NEXT CHC OF RAIN WILL COME SATURDAY
WHEN HIGH PRESSURE OVER THE GREAT LAKES WILL DRIFT EAST ALLOWING A
COLD FRONT TO APPROACH. THE NAM IS QUICKER MOVING THE FRONT EAST
THAN THE GFS AND TO SOME DEGREE THE ECMWF. HOWEVER INSTABILITY WILL
INCREASE DURING THE AFTERNOON AND A SHOWER/STORM CAN/T BE RULED OUT.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 AM EDT THU JUN 13 2013

THE UPPER RIDGE OVER THE REGION ON SATURDAY IS PROGGED TO BREAK DOWN
AND A MORE ZONAL FLOW REGIME SETS UP FROM SATURDAY NIGHT THROUGH
MONDAY. RETURNING WARM ADVECTION PATTERN SHOULD RESULT IN OCCASIONAL
MCS ACTIVITY ACROSS THE UPPER MIDWEST... BUT CONFIDENCE IS LOW AS TO
HOW MUCH TSTM ACTIVITY WILL IMPACT SW LWR MI. CURRENT GUIDANCE
SUGGESTS THAT WE WILL ONLY BE CLIPPED BY THE NRN FRINGES OF STRONGER
MCS/S ROLLING FROM IOWA EASTWARD ACROSS NRN IL/IN.

OUR BEST CHANCE OF SHOWERS AND TSTMS LOOKS TO COME ON MONDAY INTO
MONDAY EVENING WHEN THE UPPER LOW NOW OVER THE PACIFIC NORTHWEST
PASSES THROUGH THE GREAT LAKES REGION. HIGH PRESSURE BUILDS IN AGAIN
BEHIND THAT FEATURE AND BRINGS DRY WEATHER FOR TUESDAY AND WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 115 PM EDT THU JUN 13 2013

VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. HOWEVER THERE
WAS A BAND OF CLOUDS EXTENDING FROM EASTERN LAKE SUPERIOR...
THROUGH THE U.P. AND INTO NE WISCONSIN. THESE CLOUDS WILL SLIDE SE
THROUGH LOWER MI...IMPACTING THE TAF SITES BY EARLY/MID EVENING.
CEILINGS SHOULD RANGE FROM 3-5K FT. THE CLOUDS SHOULD HANG AROUND
INTO FRIDAY MORNING...BUT SHOULD CLEAR FROM NORTH TO SOUTH LATE
FRIDAY MORNING.

&&

.MARINE...
ISSUED AT 1056 AM EDT THU JUN 13 2013

CURRENT FORECAST LOOKED GOOD WITH A SMALL CRAFT ADVISORY. GUSTY
NORTHERLY FLOW AND COLD AIR ADVECTION WILL RESULT IN BUILDING
WAVES TODAY.


&&

.HYDROLOGY...
ISSUED AT 328 AM EDT THU JUN 13 2013

RADAR INDICATED 4-5 INCHES OF RAIN FELL EARLIER FROM ALLEGAN TO
INGHAM COUNTIES. THIS HAS RESULTED IN FLOODING IN SEVERAL LOCATIONS
WITH THE WORST IN EATON COUNTY WHERE I-69 IS FLOODED NEAR
POTTERVILLE. LIGHT RAIN IS POSSIBLE THIS AFTERNOON OVER THE ERN HALF
OF THE CWA BUT QPF SHOULD BE LESS THAN A QUARTER INCH.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY MORNING FOR MIZ037-043-
     050-056-064-071.

LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR LMZ844>849.

&&

$$

UPDATE...MJS
SYNOPSIS...93
SHORT TERM...93
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...93
MARINE...MJS