Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 020343
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1145 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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1145 PM EDT MON SEP 1 2014

PRIMARILY VFR CONDITIONS ARE ANTICIPATED OVERNIGHT WITH ISOLATED
LINGERING LIGHT RAIN SHOWERS. PATCHY MVFR OR IFR VISBYS/CIGS MAY
DEVELOP DURING THE EARLY MORNING HOURS TUESDAY SOUTHEAST OF GRR.

THERE IS ALSO POTENTIAL FOR SOME LOWER CIGS/VISBYS AND A FEW SHOWERS
TO CLIP MAINLY KJXN DURING THE EARLY TO MID MORNING HOURS TUESDAY.
HOWEVER MOST OF THE SHOWERS SHOULD STAY FURTHER SOUTH TO SOUTHEAST
OF SOUTHERN LWR MI.

VFR CONDITIONS ARE ANTICIPATED TUESDAY AT ALL THE TERMINALS AFTER
ANY PATCHY MORNING FOG AND LOW CLOUDS MIX OUT. SKIES WILL CLEAR WITH
VFR CONDITIONS CONTINUING TUESDAY NIGHT.

&&

.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...NONE.

LM...NONE.

&&

$$

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







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