Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 310225
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1025 PM EDT THU OCT 30 2014

LATEST UPDATE...
UPDATE/MARINE

.SYNOPSIS...
ISSUED AT 338 PM EDT THU OCT 30 2014

ACTIVE WEATHER WILL BE MOVING INTO SOUTHWEST MICHIGAN LATER TONIGHT
AND INTO FRIDAY.  RAIN WILL BECOME WIDESPREAD AFTER MIDNIGHT
TONIGHT.  THEN AS COLDER AIR ARRIVES FRIDAY MORNING THE RAIN IS
EXPECTED TO CHANGE TO SNOW FROM NORTHWEST TO SOUTHEAST THROUGH THE
DAY.  BY FRIDAY EVENING MOST AREAS WILL ONLY SEE AN INCH OR LESS OF
SNOW ON GRASSY AREAS.  WINDS WILL ALSO BECOME QUITE STRONG INTO
FRIDAY WITH GUSTS AS HIGH AS 50 MPH ALONG THE LAKE SHORE...AND 45
MPH INLAND.  THE WINDS WILL DIMINISH FRIDAY EVENING.

THE WEEKEND LOOKS DRY BUT COOL WITH HIGHS ONLY 40 TO 45.  ANOTHER
PERIOD OF RAIN IS EXPECTED MONDAY NIGHT INTO MID WEEK.  TEMPERATURES
SHOULD WARM SLIGHTLY...INTO THE UPPER 40S TO MID 50S.

&&

.UPDATE...
ISSUED AT 1019 PM EDT THU OCT 30 2014

BASED ON RADAR AND MODEL TRENDS...THE STEADIER PRECIPITATION WILL
BE DELAYED A FEW HOURS TONIGHT. HIGH POPS STILL WARRANTED.
INCOMING GUIDANCE SUPPORTS AT LEAST ADVISORY LEVEL WINDS FOR MUCH
OF THE REGION. CLOSE CALL FOR WARNING CRITERIA WINDS ON THE LAKESHORE.
UPDATED FORECAST REFLECTS LOWER POPS FOR THE FIRST HALF OF THE NIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 338 PM EDT THU OCT 30 2014

STRONG NORTH WINDS WILL BE COMING INTO THE REGION BY FRIDAY MORNING
AS COLD ADVECTION POURS IN BEHIND AN EXITING COLD FRONT.  WILL BE
HOISTING A WIND ADVISORY FOR THIS AS TREE LIMBS COULD COME DOWN
ALONG WITH ISOLATED POWER OUTAGES.  RAIN WILL SPREAD IN WITH THE
FRONT LATE TONIGHT AND AS THE COLDER AIR ARRIVES...THE RAIN WILL
CHANGE TO SNOW FROM NW TO SE ON FRIDAY.

THE COLD FRONT WILL CUT ACROSS THE AREA TONIGHT BRINGING
RAIN...ESPECIALLY AFTER MIDNIGHT.  THIS WILL BECOME INCREASINGLY
ENHANCED BY THE LAKE THROUGH THE NIGHT AS H8 TEMPS DIP TO AROUND -4C
BY 12Z FRI.

EXPECT A GRADUAL TRANSITION TO SNOW FROM NORTHWEST TO SOUTHEAST
THROUGH FRIDAY AS H8 TEMPS CONTINUE DOWNWARD TOWARD -8C BY FRIDAY
EVENING.  THE MODELS...ESPECIALLY THE GFS...CONTINUES TO SHOW A
DEFORMATION ZONE COMING THROUGH DURING THE AFTERNOON.  THIS SHOULD
COME IN AS A RAIN/SNOW MIX...BUT AS THE PCPN INTENSIFIES EXPECT IT
TO CHANGE TO ALL SNOW.  LAKE ENHANCEMENT WILL DIMINISH THROUGH THE
DAY HOWEVER AS WINDS PIVOT TO THE NORTH NORTHEAST.  A QUICK BURST OF
SNOW WITH THE DEFORMATION ZONE MAY PUT DOWN UP TO AN INCH OF SNOW.
THE FAVORED AREAS SHOULD BE ACROSS THE HIGHWAY 10 REGION.  AND ALSO
OVER THE SE CWA AS THE SURFACE LOW CONTINUES TO INTENSIFY.  THE SE
CWA MAY ALSO SEE SOME LAKE ENHANCEMENT COMING OFF OF LAKE HURON
FRIDAY NIGHT.

AS FOR THE WIND...MIXING SHOULD NOT BE A PROBLEM BEHIND THE COLD
FRONT FRIDAY.  WINDS ARE PROGGED TO BE SUSTAINED AROUND 30
MPH...WITH GUSTS NEAR 50 MPH ALONG THE LAKE SHORE.  IT SHOULD BE
SLIGHTLY LOWER INLAND...BUT IT WILL BE ENOUGH TO PUSH US INTO
ADVISORY LEVELS.  THE HIGHEST WINDS SHOULD OCCUR FRIDAY AFTERNOON.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 338 PM EDT THU OCT 30 2014

UPPER RIDGING WILL PUSH THROUGH THE GREAT LAKES OVER THE WEEKEND
BRINGING A REPRIEVE FROM FRIDAY/S ACTIVE WEATHER. A SURFACE RIDGE OF
HIGH PRESSURE SATURDAY NIGHT WILL AID IN A COLD NIGHT...WHERE LOWS
WILL DIP INTO THE 20S IN MANY AREAS. THE FAR NORTHEAST UP TOWARDS
CLARE WILL SEE LOWS AROUND 20.

AN UPPER SHORTWAVE TROUGH WILL CREST THE RIDGE ACROSS CANADA EARLY
NEXT WEEK...PUSHING A SURFACE FRONTAL SYSTEM THROUGH THE GREAT
LAKES. CHANCES FOR RAIN ARE IN THE FORECAST MONDAY THROUGH
WEDNESDAY. THE BEST CHANCES FOR PRECIPITATION WILL COME MONDAY
NIGHT AND TUESDAY WHEN THE COLD FRONT IS PROGRESSING THROUGH THE
AREA. SOME SCATTERED SHOWERS WILL REMAIN POSSIBLE WEDNESDAY INTO
THURSDAY AS A WEAK SECONDARY LOW MOVES THROUGH THE REGION.

TEMPERATURES WILL MODERATE FROM SATURDAY INTO EARLY NEXT WEEK. HIGHS
ON SATURDAY WILL ONLY REACH AROUND 40 DEGREES WHICH WILL BE 15
DEGREES BELOW NORMAL. READINGS WILL PUSH BACK TO NORMAL FOR NEXT
WEEK WITH HIGHS IN THE LOWER TO MIDDLE 50S EACH DAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 713 PM EDT THU OCT 30 2014

IMPACTS TO AVIATORS WILL INCREASE THROUGH THE PERIOD IN SOUTHWEST
MICHIGAN.

CLOUD BASES WILL LOWER INTO THE MVFR LEVEL...MAINLY
AFTER 06Z WITH RAIN MOVING IN. THERE IS A RISK FOR IFR AFTER
06Z...BUT I WAS NOT CONFIDENT ENOUGH TO ADD IT TO THE 06Z TO 12Z
PERIOD. AFTER 12Z...THERE IS SOME IFR IN THE FORECAST WITH
VISIBILITIES LOWERING. CLOUD BASES COULD LOWER INTO THAT CATEGORY
AS WELL. THE RAIN WILL MIX WITH AND CHANGE TO A PERIOD OF SNOW
DURING THE DAY AS WINDS INCREASE CONSIDERABLY. GUSTS OVER 40 KT
ARE LIKELY FOR LAKESHORE AIRPORTS WITH INLAND VALUES OVER 32 KNOTS
EXPECTED.

THERE IS A RISK FOR THUNDERSTORMS OVER LAKE MICHIGAN DURING THE
DAY ON FRIDAY. AT THIS POINT THE RISK IS TOO LOW FOR KMKG TO ADD
IT TO THE FORECAST.

I DID DECREASE THE PRECIPITATION LATER FRIDAY AFTERNOON INTO THE
EVENING. THERE COULD BE SOME LINGERING AREAS OF SNOW SHOWERS.


&&

.MARINE...
ISSUED AT 1019 PM EDT THU OCT 30 2014

CLOSE CALL FOR STORM CRITERIA WINDS. STILL A LOT OF GUIDANCE
COMING IN. THIS SYSTEM STRENGTHENS AS IT TRACKS THROUGH THE
REGION...WHICH MAKES ADDS TO THE COMPLEXITY OF THE FORECAST. WILL
MAINTAIN THE HIGH END GALE. AS FOR THE TIMING....STILL LOOKS LIKE
CLOSE TO 8 AM FOR THE START OF THE GALE FORCE WINDS.

&&

.HYDROLOGY...
ISSUED AT 338 PM EDT THU OCT 30 2014

NO HYDRO ISSUES EXPECTED...THE PERIOD OF PCPN FROM TONIGHT THROUGH
FRIDAY NIGHT SHOULD ONLY AMOUNT TO AROUND A QUARTER INCH.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY FROM 10 AM FRIDAY TO 2 AM EDT SATURDAY FOR
     MIZ037>040-043>046-050>052-056>059-064>067-071>074.

LM...GALE WARNING FROM 8 AM FRIDAY TO 5 AM EDT SATURDAY FOR
     LMZ844>849.

&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...MJS
HYDROLOGY...JK
MARINE...MJS






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