Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 291659
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1259 PM EDT MON SEP 29 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 AM EDT MON SEP 29 2014

ANOTHER WARM DAY IS EXPECTED TODAY WITH TEMPERATURES RISING INTO THE
70S IN MOST AREAS. A COLD FRONT WILL SURGE SOUTH THROUGH THE AREA
THIS AFTERNOON AND EVENING BRINGING RAIN SHOWERS AND COOLER AIR.
TEMPERATURES ON TUESDAY WILL ONLY REACH HIGHS AROUND 60 DEGREES
BENEATH A MOSTLY CLOUDY SKY. TEMPERATURES WILL REBOUND WEDNESDAY AND
THURSDAY BEFORE ANOTHER COLD FRONT PUSHES THROUGH BRINGING SHOWERS
AND STORMS FOR THURSDAY AND THURSDAY NIGHT. COOLER WEATHER IS
EXPECTED FOR NEXT WEEKEND.

&&

.UPDATE...
ISSUED AT 1123 AM EDT MON SEP 29 2014

MINOR TWEAKS MADE TO THE FORECAST. FIRST OFF...DELAYED ANY POPS
OVER THE NORTHERN CWA UNTIL AFTER 20Z AS THE FRONT COMES DOWN.
ALSO ADDED THE SLIGHT CHANCE OF THUNDER TO THE FORECAST WITH
SURFACE BASED LI/S AROUND -1C LATER THIS AFTERNOON.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 329 AM EDT MON SEP 29 2014

MAIN FOCUS IN THE SHORT TERM PERTAINS TO THE COLD FRONTAL PASSAGE
THIS AFTERNOON AND EVENING. HAVE POPS RISING TO LIKELY ACROSS
CENTRAL LOWER MICHIGAN THIS AFTERNOON AND IN ALL AREAS THIS EVENING.
EXPECTING A BAND OF RAIN SHOWERS TO SAG SOUTH THROUGH THE
AREA...EXITING THE SOUTH OVERNIGHT. THERE IS A VERY SMALL CHANCE FOR
AN ISOLATED THUNDERSTORM ACROSS THE NORTHEAST CWA TOWARDS CLARE THIS
AFTERNOON AND EARLY EVENING...BUT THOUGHT THE CHANCES WERE TOO LOW
TO INCLUDE AT THIS TIME.

PREVALENT LOW CLOUDS LOOK TO BE IN PLACE FOR TUESDAY WHICH WILL HOLD
TEMPERATURES BELOW SEASONAL NORMALS. HIGHS SHOULD HOLD IN THE UPPER
50S AND LOWER 60S. THE AIRMASS BEHIND THIS FRONT IS COOL...WITH SOME
30S F TEMPS NORTH OF LAKE SUPERIOR AT THIS TIME.

QUIET WEATHER RETURNS FOR WEDNESDAY AS A RIDGE OF HIGH PRESSURE
SLIDES THROUGH THE GREAT LAKES. TEMPERATURES REBOUND QUICKLY ON
WEDNESDAY TOWARDS NORMALS IN THE UPPER 60S TO AROUND 70.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 329 AM EDT MON SEP 29 2014

DIDN`T MAKE TOO MANY CHANGES TO THE FORECAST. MODELS ARE STILL IN
AGREEMENT THAT A COLD FRONT WILL SWEEP THROUGH LOWER MICHIGAN
THURSDAY NIGHT. WE/LL HAVE TO WATCH FOR THE POTENTIAL FOR STRONG
STORMS THURSDAY NIGHT. INSTABILITY IS A BIT WEAK AHEAD OF THE FRONT
BUT OTHER DYNAMICS ARE FAIRLY STRONG. SHEAR NEAR 50 KTS COULD RESULT
IN SOME ORGANIZATION BUT OVERALL THE SEVERE THREAT IS MINIMIZED BY
THE LOW INSTABILITY.

THE UPPER LOW WILL SETTLE OVER THE GREAT LAKES SATURDAY AND RESULT
IN SCATTERED SHOWERS ACROSS THE CWA. TEMPS WILL REMAIN MOSTLY IN THE
MID 50S SATURDAY BEFORE CLIMBING TO AROUND 60 SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1258 PM EDT MON SEP 29 2014

VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON AT ALL TAF SITES.
WINDS SHOULD BECOME WEST SOUTHWEST AT ALL TAF SITES BY MID
AFTERNOON BUT STAY LESS THAN 10 KNOTS.

TONIGHT EXPECT SHOWERS WITH THE COLD FRONT... MOSTLY BEHIND THE
FRONT ACTUALLY. THERE WILL BE 3 HOUR WIDE RAIN BAND THAT WILL
CROSS MOST OF THE CWA. LOCATIONS NEAR I-69 MAY HAVE A LONGER
PERIOD OF SHOWERS. CIGS/VSBY SHOULD QUICKLY BECOME MVFR BEHIND THE
FRONT. ONCE THE RAIN ENDS...MVFR CIGS SHOULD CONTINUE THROUGH MOST
OF TUESDAY. TAF SITES NEAR I-69 SHOULD MAY ALSO SEE A PERIOD OF
IFR CIGS DURING THE EARLY MORNING HOURS OF TUESDAY.

IT IS POSSIBLE THERE COULD BE A FEW ISOLATED THUNDERSTORMS WITH
THE COLD FRONT THIS EVENING BUT AT THIS POINT THEY SEEM TO
ISOLATED TO PUT IN THE TAF FORECAST.

&&

.MARINE...
ISSUED AT 329 AM EDT MON SEP 29 2014

WILL BE HOISTING A SMALL CRAFT ADVISORY WITH THIS ISSUANCE OF THE
NEARSHORE AS STRONG NORTH WINDS RAMP UP THIS AFTERNOON AND EVENING
BEHIND THE FRONTAL PASSAGE. WAVES WILL REMAIN UP THROUGH TUESDAY
AFTERNOON. WINDS WILL PUSH TOWARDS 30 KNOTS AT TIMES OFF SHORE WITH
WAVES BUILDING TO 4 TO 7 FEET TONIGHT.


&&

.HYDROLOGY...
ISSUED AT 329 AM EDT MON SEP 29 2014

RAINFALL WITH THIS FRONTAL PASSAGE WILL BE LIGHT...FROM TRACE
AMOUNTS IN SOME AREAS TO A TENTH OR TWO IN A FEW SPOTS. RIVERS ARE
LOW AND WITH LIMITED RAINFALL WE HAVE NO HYDRO CONCERNS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 8 PM EDT
     TUESDAY FOR LMZ847>849.

     SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT TUESDAY
     FOR LMZ844>846.

&&

$$

UPDATE...JK
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...WDM
HYDROLOGY...DUKE
MARINE...DUKE





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