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000
FXUS63 KGRR 082356
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
656 PM EST SAT MAR 8 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 230 PM EST SAT MAR 8 2014

AN AREA OF HIGH PRESSURE OVER THE CENTRAL PLAINS WILL BUILD EAST
THROUGH SUNDAY. THIS SYSTEM WILL PROVIDE FAIR WEATHER TO THE
GREAT LAKES REGION. WEAK LOW PRESSURE WILL TRACK EASTWARD THROUGH
THE NORTHERN GREAT LAKES REGION MONDAY. A COOLER AIRMASS WILL
FILTER IN BEHIND THIS SYSTEM FOR TUESDAY INTO WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 230 PM EST SAT MAR 8 2014

THE MAIN FORECAST CHALLENGE DEALS WITH THE RISK FOR PRECIPITATION.
CHANCES OVERALL REMAIN LOW AND NO MAJOR CHANGES TO THE FORECAST
WITH THIS ISSUANCE. SUNDAY NIGHT ONE MID LEVEL SHORTWAVE TRACKS
RAPIDLY SOUTHEASTWARD THROUGH LAKE SUPERIOR. THERE IS SOME
MOISTENING OF THE DGZ...AND LIFT FROM THE WAVE HERE IN SW LOWER MI.
GIVEN THE TRACK OF THIS SYSTEM...I WILL FEATURE LOW POPS FOR THE
REGION NORTH OF A HART TO MOUNT PLEASANT LINE. FURTHER SOUTH...AT
THIS POINT LITTLE OR NO LIFT AROUND TO SUPPORT ADDING POPS.

WE WILL NEED TO MONITOR MONDAY NIGHT FOR POSSIBLY ADDING
PRECIPITATION TO THE FORECAST. NAM AND HIGH RES EURO KEEP IT
DRY...BUT THE GFS IS SHOWING THE DGZ BECOMING MOIST. THIS IS
RELATED TO MID LEVEL FGEN WITH IS STRONGER WITH THE GFS. I HELD
OFF ON MENTIONING PRECIPITATION GIVEN THE GFS SEEMS TO BE AN OUTLIER.

WITH SKIES CLEARING OUT THIS EVENING...DEWPOINTS ARE ELEVATED
COMPARED TO FORECASTED LOW TEMPERATURES. AS A RESULT WE MAY SEE
SOME FOG/STRATUS TRYING TO DEVELOP VERY LATE. NAM AND HRRR MODELS
ARE SHOWING THIS. I ADDED IT TO THE FORECAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 230 PM EST SAT MAR 8 2014

IT STILL APPEARS THE MID WEEK SYSTEM WILL TRACK ALONG THE OHIO RIVER
VALLEY...LEAVING SOUTHERN LOWER MICHIGAN ON THE NORTHERN FRINGES OF
THIS SYSTEM.  THE PCPN COULD START TUESDAY AFTERNOON ALONG AND SOUTH
OF I-96 ALONG A REGION OF FGEN.  THEN THE PCPN SHOULD EXPAND AND
CONTINUE INTO TUESDAY NIGHT AND WEDNESDAY AS THE LOW PASSES TO OUR
SOUTH.  THROUGH MIDNIGHT TUESDAY NIGHT RAIN AND/OR SNOW COULD
OCCUR...WITH MAINLY SNOW FROM MIDNIGHT TUESDAY NIGHT ONWARD.  BEING
THE NORTHERN FRINGE SHOULD GIVE THE AREA MOSTLY LIGHT SNOW...WITH
LESS THAN AN INCH EXPECTED FOR I-96...UP TO TWO INCHES OVER THE FAR
SE CWA...TOWARD JXN.

ONCE THIS SYSTEM GOES BY THE REST OF THE LONG TERM APPEARS TO BE
QUIET.  A CLIPPER SYSTEM GOES BY TO OUR NORTH ON FRIDAY...BUT THE
BEST MOISTURE REMAINS NORTH...SO IT MAY GO BY DRY.

AFTER A NEAR NORMAL START TO TEMPS ON TUESDAY WITH HIGHS AROUND
40...WE WILL SEE MUCH COOLER AIR ARRIVE BEHIND THE MID WEEK SYSTEM.
HIGHS IN THE UPPER 20S TO AROUND 30 ARE EXPECTED WED AND THU.  TEMPS
SHOULD BE BRIEFLY WARMER FRIDAY AHEAD OF THE CLIPPER...THEN COOLER
AGAIN FOR SATURDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 656 PM EST SAT MAR 8 2014

MVFR CIGS CONTINUE TO CLEAR FROM NORTH TO SOUTH THIS EVENING WITH
THE EDGE JUST COMING THROUGH GRR AS OF 2230Z. THE REST OF THE
AREA SOUTH AND EAST OF GRR SHOULD SCATTER OUT OVER THE NEXT FEW
HOURS BUT IT MAY TAKE UNTIL ALMOST MIDNIGHT FOR THE CLEARING TO
REACH JXN.

FOG/STRATUS FORMATION IS A CONCERN FOR THE LATE NIGHT PERIOD BUT
WAS NOT CONFIDENT ENOUGH TO PUT THIS THREAT IN THE TAFS. GUIDANCE
SHOWS NORTH WINDS OF 10-15 KNOTS JUST ABOVE THE SFC WHICH SHOULD
MITIGATE THE THREAT.

VFR CONDITIONS ARE LIKELY ON SUNDAY WITH CLOUD BASES AOA 12K FEET.
SOUTHWEST WINDS WILL INCREASE AND BECOME RATHER STRONG/GUSTY
DURING THE AFTERNOON WITH GUSTS TO 30KTS POSSIBLE ESPECIALLY AT
KMKG.

&&

.HYDROLOGY...
ISSUED AT 230 PM EST SAT MAR 8 2014

NO MAJOR PRECIPITATION SYSTEMS SEEN THROUGH THE FORECAST PERIOD. A
MODERATING TREND IN THE TEMPERATURES IS PREDICTED FOR MONDAY INTO
TUESDAY. THIS WILL LEAD TO GRADUAL MELTING. TEMPERATURES DO COOL
DOWN FOR THE MIDDLE PART OF THE WEEK WHICH WILL SLOWLY DOWN OR
STOP ANY MELTING. TEMPERATURES THEN TRY TO MODERATE FOR THE END OF
THE WEEK. AS A RESULT...THE SNOWPACK WILL ONLY SLOWLY RELEASE SOME
OF ITS WATER THROUGH THE PERIOD. WITH LIMITED RUNOFF WATER LEVELS
SHOULD STAY FAIRLY STABLE THIS WEEK.

&&

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

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...JK
AVIATION...MEADE
HYDROLOGY...MJS