Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 012359
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
759 PM EDT MON SEP 1 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 301 PM EDT MON SEP 1 2014

ISOLATED SHOWERS ARE EXPECTED TONIGHT AS A WEAK COLD FRONT PUSHES
THROUGH. MAINLY FAIR...WARM...AND DRIER WEATHER RETURNS FOR
TUESDAY AND WEDNESDAY BEFORE MUGGY AIR RETURNS WITH A CHANCE OF
THUNDERSTORMS THURSDAY INTO FRIDAY.

&&

.UPDATE...
ISSUED AT 610 PM EDT MON SEP 1 2014

UPDATED THE GRIDS TO REFLECT LOWER POPS. STILL A CHANCE THAT SOME
CONVECTION FROM WISCONSIN MAY MOVE OVER THE CWA THIS EVENING. THEN
LATE TONIGHT SOME PCPN MAY MOVE NWD INTO THE FAR SE CWA AS IT
MOVES ACROSS INDIANA/OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 301 PM EDT MON SEP 1 2014

ISOLATED SEVERE WEATHER THREAT WILL CONTINUE ALONG AND EAST OF
U.S. ROUTE 127 THROUGH THE LATE AFTERNOON HOURS AS THE LEADING
EDGE OF DRIER AND SLIGHTLY COOLER AIR WORKS IN FROM THE WEST.
ALTHOUGH THE CONVECTION HAS REMAINED SOMEWHAT SHALLOW DUE TO A
LACK OF DEEPER UPPER DIVERGENCE...INSTANTANEOUS RAINFALL RATES
HAVE BEEN IMPRESSIVE WITH NEAR ZERO VISIBILITIES WITH THE LINE OF
SHOWERS.

STILL A FAIR AMOUNT OF INSTABILITY AHEAD OF THE LINE FOR KLAN DOWN
TOWARDS KJXN WITH CAPE OF ~1000 J/KG AND 0-6 KM BULK SHEAR OF
35-40 KTS...BUT THE DEEPER LIFT ASSOCIATED WITH UPPER
SHORTWAVE/LF EXIT REGION OF ASSOCIATED JETLET ARE MOVING NORTHEAST
ACROSS NORTHERN LOWER. SO WHILE THERE IS STILL A THREAT...IT
SHOULD REMAIN FAIRLY ISOLATED.

ALTHOUGH LOW LEVELS DRY OUT SOMEWHAT OVERNIGHT COULD NOT RULE OUT
A FEW ISOLATED SHOWERS ON TUESDAY MORNING AS THERE WILL BE A
COUPLE OF WEAK SHORTWAVES/UPPER DIVERGENCE MOVING THROUGH BETWEEN
12Z AND 18Z. OTHERWISE PRETTY FAIR AND SEASONABLE WEATHER THROUGH
WEDNESDAY.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 301 PM EDT MON SEP 1 2014

NEXT SYSTEM ALSO PASSES WELL NORTH OF THE REGION LATE THU INTO FRI
WITH MUGGY AIRMASS RETURNING LATE ON THU. COULD SEE SOME
SHOWERS/T-STORMS EARLY THU ASSOCIATED WITH WARM FRONT AND
LOW LEVEL JET. NEXT CHANCE WOULD THEN FOLLOW FRI MORNING WITH THE
TRAILING COLD FRONT.

OVERALL THIS SYSTEM IS LOOKING SIMILAR TO THE PRESENT
ONE WITH AN ISOLATED SEVERE THREAT...THERE WILL BE ABUNDANT
MOISTURE...CAPE OF 1000J/KG+ AND MARGINALLY HIGH BULK SHEAR BUT
THE DEEPER LIFT WILL PASS NORTH OF US ONCE AGAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 758 PM EDT MON SEP 1 2014

PRIMARILY VFR CONDITIONS AND ISOLATED RAIN SHOWERS ARE EXPECTED
THIS EVENING. CANT COMPLETELY RULE OUT A TSTM BUT THE RISK IS TOO
LOW TO HAVE IN THE TAFS.

IT IS POSSIBLE THAT MVFR OR EVEN IFR VSBYS/CIGS WILL DEVELOP AFTER
06Z ESPECIALLY SOUTH AND EAST OF GRR WHERE DEW PTS SHOULD STAY IN
THE MID TO UPPER 60S OVERNIGHT. HOWEVER GOING AGAINST THE FORMATION
OF LATE NIGHT STRATUS AND FOG IS THAT THERE SHOULD BE FAIRLY
EXTENSIVE MID LEVEL CLOUDINESS MOVING OVER SRN LWR MI 06Z-12Z
RELATED TO CONVECTION PASSING SOUTH OF THE STATE. THIS WILL LIMIT
RADIATIONAL EFFECTS.

THE OTHER QUESTION FOR LATE TONIGHT IS WHETHER OR NOT SE LWR MI
GETS CLIPPED BY THE RAIN PASSING BY TO THE SOUTH. DECIDED TO GO
WITH A PERIOD OF LOWER CIGS/VSBYS AT JXN 11Z-15Z BASED ON CONSENSUS
OF LATEST GUIDANCE.

VFR IS LIKELY ON TUESDAY ONCE ANY MORNING FOG/STRATUS MIXES OUT.

&&

.MARINE...
ISSUED AT 301 PM EDT MON SEP 1 2014

HEADLINES WILL EXPIRE THIS EVENING.  WINDS HAVE SHIFTED ONSHORE AT
THIS TIME AND WILL BEGIN TO DIMINISH THIS EVENING. BUOYS CONTINUE
TO SHOW WAVES OF 3 TO 4 FT WITH OCCASIONAL 5 TO 6 FOOTERS. ALL
SHOULD SUBSIDE BELOW 3 FT BY LATE EVENING. WE`LL LIKELY SEE A
REPEAT OF WIND/WAVES WITH NEXT SYSTEM THU INTO FRI.


&&

.HYDROLOGY...
ISSUED AT 1237 PM EDT MON SEP 1 2014

RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW
BANK FULL. PRECIPITATION THROUGH THIS EVENING IS EXPECTED TO TOTAL
AROUND A QUARTER OF AN INCH WITH ISOLATED LOCATIONS NORTHWEST OF
GRAND RAPIDS RECEIVING NEARLY AN INCH. THIS SHOULD LEAD TO SMALL
RISES ON AREA RIVERS WITH PEAK LEVELS BELOW BANK FULL BY MID WEEK.
ADDITIONAL PRECIPITATION IS POSSIBLE WEDNESDAY INTO FRIDAY NIGHT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ037-
     043-050-056-064-071.

LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849.

&&

$$

UPDATE...93
SYNOPSIS...COBB
SHORT TERM...COBB
LONG TERM...COBB
AVIATION...MEADE
HYDROLOGY...63
MARINE...COBB






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