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000
FXUS63 KGRR 251644
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1245 PM EDT SAT MAY 25 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 AM EDT SAT MAY 25 2013

THE REGION WILL SEE COOL AND DRY WEATHER FOR THE WEEKEND WITH HIGH
PRESSURE OVERHEAD.  THERE COULD BE A FEW SHOWERS OR ISOLATED
THUNDERSTORMS THAT DEVELOP BY LATE SUNDAY NIGHT INTO MEMORIAL DAY...
ESPECIALLY OVER THE FAR SOUTHWEST PORTION OF THE STATE.

MORE SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE FROM MONDAY NIGHT
INTO WEDNESDAY.  MORE SHOWERS AND STORMS MAY RETURN BY FRIDAY.
TEMPERATURES WILL WARM TO 80 TO 85 FROM TUESDAY THROUGH FRIDAY.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 329 AM EDT SAT MAY 25 2013

CI CLOUDS FROM OVERNIGHT STORMS OVER MN AND IA HAVE SPREAD INTO
LOWER MI.  THESE SHOULD BE THICKEST THROUGH MID MORNING THEN THEY
SHOULD THIN AND ERODE AS THE SURFACE AND UPPER RIDGE TAKES OVER.  SO
BOTTOM LINE...MORE SUN FOR THE AFTERNOON THAN THE MORNING.  A BIT
WARMER TODAY WITH HIGHS IN THE 60S.

IT LOOKS LIKE THE MID LEVEL DRY AIR FROM CENTRAL CANADA WILL KEEP SW
MI MOSTLY CLEAR TONIGHT AND THROUGH MUCH OF SUNDAY.  HOWEVER BROKEN
CLOUDS MAY TRY TO MOVE BACK INTO THE SW CORNER OF THE STATE LATE
SUNDAY WITH MORE UPSTREAM DEBRIS CLOUDS.  A FEW DEGREES WARMER
SUNDAY...65 TO 70.

THE FORECAST BECOMES MORE COMPLICATED INTO THE SUNDAY NIGHT AND
MEMORIAL DAY PERIOD.  A WARM FRONT IS TO DEVELOP TO OUR SOUTH AND
THE MODELS ARE NOT IN GOOD AGREEMENT AS TO WHERE THIS FRONT WILL
BE...ANYWHERE FROM FAR SOUTHERN INDIANA TO NEAR THE MI/IN BORDER.
THE MORE NORTHERN SOLUTIONS HAVE ELEVATED CONVECTION INTO FAR SW
LOWER MI LATE SUNDAY NIGHT...THAN SPREADS THAT INTO MUCH OF WESTERN
MI MONDAY AFTERNOON.  HAVE DECIDED TO ADD LOW CHANCE POPS TO MUCH OF
THE AREA MONDAY AFTERNOON.  AND AS MENTIONED THE FAR SW CWA MAY SEE
A FEW SHOWERS AS EARLY AS LATE SUNDAY NIGHT.  THIS WILL HAVE TO BE
FINE TUNED WITH TIME...BUT THERE IS AT LEAST A CHANCE THAT MONDAY
DOES NOT REMAIN TOTALLY DRY.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 337 AM EDT SAT MAY 25 2013

TIMING OF CONVECTION WITH THE WARM FRONT LIFTING THROUGH LOWER
MICHIGAN NEXT WEEK IS THE PRIMARY FORECAST PROBLEM IN THE
EXTENDED. AS IN MANY OF THESE SITUATIONS...THE EFFECT OF CONVECTION
TRAINING ALONG THE FRONT COULD IMPEDE ITS NORTHWARD PROGRESS...SO
WILL SPREAD POPS THROUGH TUESDAY AND WEDNESDAY...WITH THE HIGHEST
POPS ON TUESDAY NIGHT. ONCE AGAIN THE GFS IS QUICKER THAN THE ECMWF
IN BRINGING THE FRONT THROUGH...SO POPS ARE ALSO SHADED A BIT HIGHER
ON TUESDAY TO ACCOUNT FOR THIS.

UPPER RIDGING SHOULD HOLD SWAY FROM LATE WEDNESDAY INTO FRIDAY...SO
DROPPED POPS FOR WED NIGHT THROUGH THURSDAY NIGHT. SFC LOW MOVING
INTO MINNESOTA ON FRIDAY ALONG WITH HEIGHT FALLS AS UPPER RIDGING
SHIFTS EAST BRINGS THREAT OF SHOWERS AND THUNDERSTORMS ACROSS
NORTHWEST ZONES.

OVERALL IT LOOKS LIKE A POTENTIALLY WET PERIOD TUESDAY INTO
WEDNESDAY AND POPS WILL PROBABLY BE INCREASED ONCE TIMING OF THE
CONVECTION IS BETTER DEFINED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1245 PM EDT SAT MAY 25 2013

VFR CONDITIONS WILL CONTINUE THROUGH SUNDAY WITH NOTHING MORE THAN
SOME HIGH CLOUD COVER AND WIND SPEEDS BELOW 10 KTS.

&&

.MARINE...
ISSUED AT 329 AM EDT SAT MAY 25 2013

A RATHER FLAT LAKE IS EXPECTED THROUGH SUNDAY NIGHT.  MONDAY SHOULD
BRING A BIT CHOPPIER CONDITIONS WITH AN INCREASING SE WIND.
HOWEVER...BEING THAT THE WINDS WILL BE OFFSHORE...THE CHOPPIEST
CONDITIONS WILL BE A MILE OR TWO OFFSHORE.  MOST LIKELY WAVES WILL
STAY BELOW SCA CRITERIA THROUGH THE THREE DAY HOLIDAY PERIOD.


&&

.FIRE WEATHER...
ISSUED AT 329 AM EDT SAT MAY 25 2013

A PERIOD OF DRY WEATHER WILL HELP THE REMAINING OLD FUELS BECOME
MORE PARCHED.  DAYTIME RH VALUES OVER THE WEEKEND WILL DROP TO
AROUND 30 PERCENT...BUT WINDS ARE LARGELY EXPECTED TO REMAIN 10 MPH
OR LESS.  A BIT MORE MOISTURE MOVES IN FOR MONDAY SO RH VALUES
SHOULD ONLY DROP TO AROUND 45 PERCENT AND THERE WILL BE THE CHANCE
FOR WIDELY SCATTERED SHOWERS/STORMS MAINLY INTO THE AFTERNOON.

&&

.HYDROLOGY...
ISSUED AT 329 AM EDT SAT MAY 25 2013

ANY PCPN OVER THE SHORT TERM WILL BE LIGHT AND SCATTERED.  THIS WILL
ALLOW HIGH RIVER LEVELS TO SUBSIDE.  AN ADVISORY IS STILL OUT FOR
THE CHIPPEWA RIVER BUT THE RIVER SHOULD FALL BACK WITHIN IT/S BANKS
OVER THE NEXT DAY OR TWO.

&&

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

&&

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...LAURENS
AVIATION...LAURENS
FIRE WEATHER...JK
HYDROLOGY...JK
MARINE...JK