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000
FXUS63 KGRR 141142
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
742 AM EDT FRI JUN 14 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 331 AM EDT FRI JUN 14 2013

HIGH PRESSURE WILL BRING DRY CONDITIONS AND COMFORTABLE TEMPERATURES
TO THE AREA THROUGH MOST OF THE DAY ON SATURDAY. THE CHANCES OF RAIN
WILL INCREASE LATER ON SATURDAY...AND WILL BE THE HIGHEST ON
SATURDAY NIGHT AS A WAVE OF LOW PRESSURE MOVES BY. MOST LOCATIONS
SHOULD SEE A ROUND OF SHOWERS AND STORMS SATURDAY NIGHT. CONDITIONS
SHOULD DRY OUT AND REMAIN MILD ON SUNDAY...BEFORE ANOTHER WAVE MOVES
THROUGH ON MONDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 331 AM EDT FRI JUN 14 2013

THE MAIN FOCUS OF THE SHORT TERM IS THE CONVECTIVE CHANCES AND
SEVERE WX THREAT FROM LATE SAT INTO EARLY SUN WITH A WAVE OF LOW
PRESSURE EXPECTED TO MOVE THROUGH. THE MAIN ADJUSTMENT TO THE FCST
WAS TO INCREASE THE RAIN CHCS FOR SAT NIGHT TO LIKELY FOR MOST OF
THE AREA...AND THEN DRY SUN OUT A BIT MORE.

NOT MUCH WEATHER TO SPEAK ABOUT FOR THE FIRST 24-30 HOURS OF THE
FCST. THE TROUGH THAT WAS RESPONSIBLE FOR ALL OF THE ACTIVE WX HERE
WED NIGHT AND THEN EAST OF HERE ON THU IS MOVING OFFSHORE ACROSS THE
MID ATLANTIC THIS MORNING. FAIRLY STRONG UPPER RIDGING MOVING OUT OF
THE PLAINS WILL CONTROL THE WEATHER THROUGH AT LEAST EARLY SAT WITH
PLENTY OF SUBSIDENCE. H850 TEMPS OF THE LOWER TEENS WILL SUPPORT
HIGHS TODAY WELL INTO THE 70S.

THE THREAT OF RAIN WILL SLOWLY INCREASE DURING THE DAY ON
SATURDAY...HOWEVER WE STILL EXPECT THAT MOST OF THE AREA WILL STAY
MOSTLY DRY THROUGH THE AFTERNOON HOURS. THIS OCCURS AS THE UPPER
RIDGE AXIS WILL SHIFT EAST OF THE CWFA SAT AFTERNOON. WE WILL THEN
SEE THE UPPER LOW ACROSS ALBERTA THIS MORNING HELP TO FLATTEN THE
UPPER RIDGE LATE SAT. AT THE SAME TIME...A SHORT WAVE RIDING ENE
FROM THE ROCKIES WILL MOVE INTO THE WRN GREAT LAKES LATE IN THE
AFTERNOON.

THE LEADING EDGE OF THE LOW LEVEL MOISTURE TRANSPORT WILL APPROACH
AROUND 00Z SUN FROM THE WSW. ENOUGH MOISTURE COULD HELP TOUCH OFF A
SHOWER SAT AFTERNOON...HOWEVER THERE DOES NOT REALLY LOOK TO BE MUCH
INSTABILITY SAT AFTERNOON.

THE SHORT WAVE WILL THEN MOVE INTO THE AREA SAT NIGHT WITH THE LLJ
PRECEDING ITS ARRIVAL. WE EXPECT SHOWERS AND SOME STORMS TO DEVELOP
JUST WEST OF THE AREA SAT EVENING AND MOVE IN OVERNIGHT SAT NIGHT.
RIGHT NOW...WE ARE NOT EXPECTING MUCH OF A SEVERE THREAT. FCST
SOUNDINGS INDICATE THAT THE INSTABILITY WILL BE MOSTLY ELEVATED.
CAPES ARE ONLY A FEW HUNDRED JOULES WITH A THIN APPEARANCE. THE FAST
MID LEVEL FLOW WOULD HELP THE SHEAR OUT...BUT GOOD INSTABILITY
SHOULD BE LACKING.

SOME SHOWERS/STORMS WILL BE POSSIBLE EARLY SUN DOWN SOUTH AS THE LLJ
AND SHORT WAVE ARE EXITING THE AREA. WOULD SHOULD SEE CLEARING SKIES
AND DRY CONDITIONS IN THE WAKE OF THE SAT NIGHT WAVE AND AHEAD OF
THE MON WAVE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 331 AM EDT FRI JUN 14 2013

HAVE OPTED TO GO WITH A DRY FCST ON SUNDAY NIGHT SINCE THERE IS A
LACK OF MOISTURE AND THE SHORTWAVE DROPPING DOWN FROM THE NORTHWEST
DOES NOT ARRIVE UNTIL AROUND 18Z MONDAY. MEDIUM RANGE GUIDANCE HAS
BEEN PRETTY CONSISTENT AND IN GOOD AGREEMENT ON THE TIMING OF THIS
SHORTWAVE AND ASSOCIATED COLD FRONT... ALTHOUGH ONLY SCATTERED
COVERAGE OF SHOWERS AND TSTMS IS EXPECTED ON MONDAY AND MONDAY
EVENING SO ONLY CHANCE POPS AT THIS TIME. BEHIND THE MONDAY
SYSTEM... THE REST OF NEXT WEEK LOOKS VERY QUIET WITH A DRY AND
PLEASANT STRETCH OF WEATHER AS SFC HIGH PRESSURE AND DRY AIR MASS
DOMINATES THE GREAT LAKES REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 742 AM EDT FRI JUN 14 2013

WIDESPREAD VFR CONDITIONS FOR SURE TODAY AND TONIGHT. THERE MAY BE
A BRIEF PERIOD OF 10 TO 20 KT WINDS FROM THE NORTHWEST THIS
AFTERNOON AT MKG DUE TO A LAKE BREEZE. OTHERWISE WINDS WILL BE
UNDER 10 KTS TODAY AND TONIGHT.

&&

.MARINE...
ISSUED AT 331 AM EDT FRI JUN 14 2013

WE ARE CANCELLING ALL MARINE HEADLINES WITH THIS MORNING/S FCST
PACKAGE. WINDS HAVE ALL COME DOWN BELOW 15 KNOTS ALONG THE COAST AND
WAVES HAVE COME DOWN TO OR BELOW 2 FEET AT THE BUOYS OFF THE COAST.
WE SHOULD REMAIN HEADLINE FREE THROUGH THE WEEKEND. THERE WILL BE
SOME INCREASE WITH THE WIND SAT NIGHT AHEAD OF THE INCOMING SYSTEM.
WE EXPECT THE WINDS TO REMAIN AT OR BELOW 20 KNOTS.


&&

.HYDROLOGY...
ISSUED AT 331 AM EDT FRI JUN 14 2013

CONDITIONS HAVE STABILIZED ACROSS THE AREA AFTER THE FLOODING THAT
OCCURRED WED NIGHT ACROSS THE SRN HALF OF THE AREA. EIGHT ADVISORIES
ARE OUT...ALL OF WHICH ARE IN THE GRAND RIVER BASIN NEAR THE AREAS
OF HEAVIEST RAINFALL WED NIGHT. WE EXPECT THAT MOST OF THE AREA WILL
SEE ANOTHER HALF TO ONE INCH OF RAINFALL CENTERED ON SATURDAY NIGHT
WITH THE WAVE EXPECTED TO MOVE BY. SOME LOCALLY HEAVIER AMOUNTS WILL
BE POSSIBLE. THIS WILL BUMP THE RIVER LEVELS UP A BIT MORE AND WE
WILL HAVE TO WATCH THE CURRENT ADVISORY AREAS FOR POSSIBLE WARNINGS.
WE EXPECT THIS WAVE WILL BE PROGRESSIVE IN NATURE...AND SHOULD NOT
CAUSE MUCH IN THE WAY OF FLASH FLOODING.

&&

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

$$

SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...NJJ
MARINE...NJJ