Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 280812
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
310 AM EST FRI NOV 28 2014

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE

.SYNOPSIS...
ISSUED AT 310 AM EST FRI NOV 28 2014

COLD WEATHER WILL CONTINUE TODAY WITH WIDESPREAD LIGHT SNOW AND
ACCUMULATIONS OF 1 TO 3 INCHES THAT COULD RESULT IN SLICK SPOTS
ON AREA ROADS. TEMPERATURES WILL MODERATE THIS WEEKEND WITH SOME
LIGHT RAIN SHOWERS AND DRIZZLE BEFORE A MUCH COLDER AIRMASS MOVES
BACK INTO LOWER MICHIGAN MONDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 310 AM EST FRI NOV 28 2014

LIGHT SNOW WILL DEVELOP ACROSS OUR FORECAST AREA TODAY IN AN AREA
OF ISENTROPIC UPGLIDE WELL TO THE NE OF THE WARM FRONT THAT WILL
LIFT SLOWLY NE INTO ILLINOIS. SNOW ACCUMULATIONS FROM MID TO LATE
MORNING THROUGH THIS EVENING WILL RANGE FROM ONE TO THREE INCHES.
HIGHEST ACCUMULATIONS WITHIN THAT RANGE CONTINUE TO LOOK MOST
PROBABLE NW OF KGRR FROM NEAR KMKG NORTHWARD TO KLDM WITH HELP FROM
SSW FLOW LAKE ENHANCED MOISTURE AND AS SUGGESTED BY 00Z ECMWF
GUIDANCE.

PCPN TYPE MAY CHANGE TO A VERY BRIEF PERIOD OF LIGHT FREEZING
DRIZZLE/LIGHT FREEZING RAIN OR SLEET LATE TONIGHT BEFORE ENOUGH
WARM AIR MOVES IN TO CHANGE PCPN TYPE TO PLAIN LIGHT RAIN SHOWERS
AND DRIZZLE SATURDAY THROUGH SUNDAY. MAX TEMPS SATURDAY WILL REACH
THE UPPER 30S TO LOWER 40S AND WILL BE WELL INTO THE 40S FOR SUNDAY.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EST FRI NOV 28 2014

EXTENDED PERIOD WILL START OFF WITH A COLD FRONT MOVING THROUGH
SUNDAY NIGHT...WHICH MAY BE ABLE TO FOCUS SOME LIGHT SNOW OR MIXED
PRECIPITATION. THEN DRIER AND COLDER AIR MOVES IN WITH SOME LIGHT
LAKE EFFECT SNOW SHOWERS POSSIBLE EARLY MONDAY. INVERSION HEIGHTS
CRASH AS AN ARCTIC HIGH BEGINS TO BUILD IN LATER IN THE DAY AND THE
SFC HIGH SHOULD BRING DRY WEATHER THROUGH TUESDAY.

WARM ADVECTION BEGINS TUESDAY NIGHT WITH SOME LIGHT SNOW OR MIXED
PRECIPITATION POSSIBLE BEFORE ANOTHER COLD FRONT MOVES THROUGH
WEDNESDAY AND THINGS DRY OUT AGAIN.

THURSDAY IS A QUESTION MARK AS SEVERAL RUNS OF THE GFS HAVE SHOWN
PRECIPITATION IN AN AREA OF ISENTROPIC UPGLIDE NORTH OF A SFC WARM
FRONT ACROSS THE OHIO VALLEY REACHING THE SOUTHERN FORECAST AREA.
THE ECWMF IS ABOUT 24 HOURS SLOWER WITH THE PROGRESSION OF THIS.
KEPT LOW CHANCE POPS IN THE FORECAST FOR NOW. PRECIP TYPE IS ALSO A
PROBLEM WITH GFS SOUNDINGS SHOWING POTENTIAL FOR MIXED PRECIP ACROSS
THE SOUTHERN HALF OF THE FORECAST AREA...WHILE THE ECWMF WOULD BE
MOSTLY LIQUID...AND NOT ARRIVING UNTIL AFTER THURSDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1128 PM EST THU NOV 27 2014

SNOW FLURRIES OR LIGHT SNOW ARE EXPECTED INTO EARLY FRIDAY
MORNING...BUT IMPACTS ARE FORECASTED TO BE MINIMAL. THE POTENTIAL
EXISTS FOR A BAND OF STEADIER SNOW TO MOVE IN FROM THE WEST AS WE
PROGRESS THROUGH FRIDAY MORNING LEADING TO IFR OR LOWER
CONDITIONS. TAF SITES KMKG...KGRR AND KLAN APPEAR TO BE AT THE
GREATEST RISK FOR THIS SNOW. FURTHER SOUTH THE SETUP FOR IMPACT
CONDITIONS IS LESS CERTAIN. THE RISK FOR SNOW WILL THEN EXIST INTO
THE EVENING.

A WARM LAYER IS SHOWN TO POTENTIALLY MOVE IN FROM THE WEST AFTER
03Z SAT AT AROUND 6000 FT. IF THIS HAPPENS WE WILL SEE THE
PRECIPITATION MIX WITH OR CHANGE TO SLEET.


&&

.MARINE...
ISSUED AT 310 AM EST FRI NOV 28 2014

A NEW SMALL CRAFT ADVISORY WILL GO INTO EFFECT FROM MID AFTERNOON
TODAY THROUGH SATURDAY AS INCREASING SOUTHERLY WINDS WILL CAUSE
WAVE HEIGHTS TO RAMP BACK UP AFTER A BRIEF LULL THIS MORNING AND
EARLY AFTERNOON.

&&

.HYDROLOGY...
ISSUED AT 310 AM EST FRI NOV 28 2014

NO HYDRO ISSUES ARE ANTICIPATED THIS WEEKEND INTO NEXT WEEK.
PRECIPITATION TODAY THROUGH THE WEEKEND INTO NEXT WEEK WILL BE
LIGHT AND NOT SIGNIFICANT ENOUGH TO CAUSE ANY HYDRO ISSUES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON THROUGH
     SATURDAY AFTERNOON FOR LMZ844>849.

&&

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...MJS
HYDROLOGY...LAURENS
MARINE...LAURENS







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