Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 281640
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1240 PM EDT SUN SEP 28 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 AM EDT SUN SEP 28 2014

ANOTHER WARM DAY IS EXPECTED WITH HIGHS REACHING THE 70S IN ALL
AREAS. NORMAL HIGHS FOR THIS TIME OF YEAR ARE MORE IN THE UPPER 60S
TO AROUND 70. QUIET WEATHER WILL CONTINUE TONIGHT AND INTO MONDAY AS
HIGH PRESSURE BEGINS TO RETREAT FINALLY FROM THE GREAT LAKES. THIS
WILL ALLOW A COLD FRONT TO DROP SOUTH THROUGH THE AREA MONDAY
AFTERNOON AND MONDAY NIGHT. THE FRONT WILL BE ACCOMPANIED BY RAIN
SHOWERS...THAT WILL BE MOST PREVALENT MONDAY EVENING. COOLER AIR
WILL FILTER IN BEHIND THE FRONT FOR TUESDAY WHERE HIGHS WILL ONLY
REACH THE LOWER TO MIDDLE 60S.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 329 AM EDT SUN SEP 28 2014

MAIN SHORT TERM FORECAST CHALLENGE IS HOW MUCH RAIN WILL BE
GENERATED BY THE FRONTAL BOUNDARY MONDAY AFTERNOON INTO TUESDAY
MORNING. THE FRONT WILL BE PUSHED THROUGH THE REGION BY A POTENT
500MB SHORTWAVE. THE ISSUE IS THE MOISTURE IS NOT ALL THAT DEEP.
1000-700MB RH DOES REACH THE 90PCT RANGE IN A NARROW RIBBON MONDAY
AFTERNOON THROUGH TUESDAY MORNING AS IT SAGS SOUTH THROUGH THE AREA.
AT THIS POINT HAVE CHANCE POPS (30-40 PCT) AS THE FRONT MOVES SOUTH.
EXPECTING AMOUNTS TO BE QUITE LIGHT. THE FRONT DOES HAVE A DECENT
PUSH OF COOLER AIR AND WE MAY NEED TO KNOCK DOWN TUESDAY/S HIGHS
EVEN A BIT MORE. TAPERED THEM BACK TO THE 60S AT THIS POINT. SOME
GUIDANCE IS SUGGESTING WE MAY HOLD AROUND 60 WITH LOW CLOUDS BEHIND
THE FRONT.

OTHERWISE FAIRLY QUIET WEATHER TO CONTINUE UP UNTIL MONDAY AFTERNOON
WITH A LITTLE BIT OF FOG THIS MORNING AND AGAIN MONDAY MORNING.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 329 AM EDT SUN SEP 28 2014

THE MAIN FOCUS OF THE LONG TERM IS THE APPROACH OF A COLD FRONT
THURSDAY/FRIDAY. HIGH PRESSURE WILL BE OVER LOWER MICHIGAN PRIOR TO
THAT AND WE/LL HAVE MILD TEMPERATURES WITH HIGHS IN THE MID 70S.

THURSDAY INTO FRIDAY LOOKS WET. A STRONG COLD FRONT WILL MOVE TOWARD
THE GREAT LAKES. THE MAIN DIFFERENCE BETWEEN THE GFS AND ECMWF IS
THE FORMATION OF A STRONG LOW ON THE SOUTHERN END OF THE COLD FRONT
ON THE GFS. THIS LOW THEN RIDES NORTHEAST ALONG THE FRONTAL BOUNDARY
THROUGH EASTERN WISCONSIN THURSDAY NIGHT/FRIDAY. THE GFS SHOWS QUITE
A BIT OF WIND WITH THIS SYSTEM DUE TO IT/S DEEPENING AS IT MOVES BY.
THE ECMWF ON THE OTHER HAND DOESN/T DEVELOP THE WAVE AND THEREFORE
IS A BIT QUICKER IN PUSHING THE COLD FRONT THROUGH LOWER MICHIGAN
THURSDAY NIGHT. CONFIDENCE IS HIGH THAT WE/LL SEE SHOWERS AND
POSSIBLY THUNDERSTORMS WITH THE COLD FRONT...BUT CONFIDENCE IS
LOWER  ON THE TIMING ASPECT.

SHOWERS ARE EXPECTED FRIDAY WITH THE TRAILING UPPER LOW MOVES OVER
LOWER MICHIGAN. STRONG COLD ADVECTION BEHIND THE FRONT AS H8 TEMPS
FALL FROM 14C TO -2C BY SATURDAY. HIGHS NEXT WEEKEND WILL LIKELY BE
IN THE 50S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1239 PM EDT SUN SEP 28 2014

JUST ONE MORE DAY OF THIS SORT OF WEATHER PATTERN. THAT IS VFR
DURING THE DAY THEN FOG AT NIGHT...LOCALLY LIFR BUT MOSTLY MVFR
TYPE FOG.

I EXPECT NEAR CALM WINDS AND NEARLY CLEAR SKIES TONIGHT SO FOG
SHOULD REDEVELOP LIKE THIS MORNING ONLY IT SHOULD BE MORE
EXTENSIVE AS THERE WILL NOT BE THE HIGH CLOUDS TO LIMIT COOLING.
AS A RESULT I BROUGHT THE MORE TYPICAL SITES LIKE AZO AND JXN TO
LIFR IN FOG TOWARD MORNING MONDAY. THE NAMDNG5 HAS BEEN DOING
NICELY WITH THE THICKNESS FOG OF LATE AND I HAVE USED THAT TO HELP
ME FIGURE OUT WHERE THE FOG WOULD BE THICKNESS. ALL OF THIS WILL
BURN OFF QUICKLY MONDAY AFTER SUNRISE. SKIES SHOULD BE NEARLY
CLEAR UNTIL LATE AFTERNOON SO VFR RETURNS TO ALL SITES BY 14Z OR
SO.

&&

.MARINE...
ISSUED AT 329 AM EDT SUN SEP 28 2014

WINDS AND WAVES WILL BE LIMITED THROUGH MONDAY. HIGH PRESSURE WILL
CONTINUE TO PROVIDE LIGHT WINDS AND LIMITED WAVE ACTION INTO MIDDAY
ON MONDAY. A FAIRLY SHARP FRONT WILL PROGRESS SOUTH THROUGH THE AREA
MONDAY AFTERNOON INTO MONDAY NIGHT WHICH WILL PROVIDE FOR A DECENT
SURGE OF NORTHERLY WINDS. WAVES MONDAY NIGHT MAY JUMP INTO THE 3 TO
6 FOOT RANGE.


&&

.HYDROLOGY...
ISSUED AT 329 AM EDT SUN SEP 28 2014

NO HYDRO CONCERNS IN THE NEXT SEVERAL DAY WITH RIVERS AT LOW LEVELS
AND INCONSEQUENTIAL RAINFALL EXPECTED. A FRONTAL BOUNDARY WILL
TRAVERSE THE AREA MONDAY AFTERNOON AND MONDAY NIGHT...BUT RAINFALL
TOTALS WILL BE LIMITED. AT THIS POINT EXPECTING RAINFALL TOTALS ON
THE ORDER OF A TENTH OF AN INCH OR LESS.

&&

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

$$

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





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