Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 211755
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1255 PM EST FRI NOV 21 2014

LATEST UPDATE...
SYNOPSIS/SHORT TERM/MARINE

.SYNOPSIS...
ISSUED AT 1255 PM EST FRI NOV 21 2014

FREEZING RAIN SATURDAY MORNING WILL GRADUALLY TRANSITION TO RAIN IN
THE AFTERNOON WITH WARMING TEMPERATURES. ON SATURDAY NIGHT AND SUNDAY
OCCASIONAL RAIN...DRIZZLE...AND FOG CAN BE EXPECTED ALONG WITH TEMPERATURES
WELL INTO THE 40S AND APPROACHING 50. COOLER AIR WILL RETURN EARLY NEXT
WEEK ALONG WITH CHANCES OF SNOW SHOWERS.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY EVENING)
ISSUED AT 1255 PM EST FRI NOV 21 2014

HAVE ISSUED A FREEZING RAIN ADVISORY FOR SATURDAY MORNING BASED ON INCREASING
CONFIDENCE. FORECAST SOUNDINGS CONTINUE TO SHOW STRONG ELEVATED THETA-E
ADVECTION FROM THE SOUTHWEST OVERSPREADING THE SIGNIFICANT SNOW PACK
OVER MUCH OF WESTERN LOWER MICHIGAN. ROADWAY SURFACES ARE BEING
EXPOSED THIS AFTERNOON WITH ABUNDANT SUNSHINE...SO SOME ICE ACCUMULATION
ON THEM SATURDAY MORNING SEEMS LIKELY. CALIBRATED SPC SREF GUIDANCE
SUPPORTS THIS WITH VERY HIGH CONDITIONAL PROBABILITY FOR FREEZING
RAIN PRIMARILY BETWEEN 1 AM AND 10 AM.

BASED ON THE EXPECTED CONVECTIVE NATURE OF PRECIPITATION SATURDAY AFTERNOON
THROUGH SUNDAY...WE HAVE GONE ABOVE WPC GUIDANCE. PLEASE SEE THE HYDROLOGY
SECTION BELOW FOR FURTHER DETAILS AND POSSIBLE IMPACTS.

DEWPOINTS WELL ABOVE FREEZING SPREADING ACROSS THE SNOW PACK WILL MAKE
FOG A LIKELY ISSUE SATURDAY NIGHT THROUGH SUNDAY. FOG IN THESE SITUATIONS
CAN BE ESPECIALLY HAZARDOUS AS VISIBILITIES CAN CHANGE VERY RAPIDLY
OVER SHORT DISTANCES DUE TO AREAS OF SNOW PACK OVER OPEN AREAS.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 326 AM EST FRI NOV 21 2014

WIDESPREAD RAIN AND MILD TEMPERATURES SUNDAY NIGHT WILL BE FOLLOWED
BY FALLING TEMPERATURES AND SNOW SHOWERS BY LATE MONDAY AS A
DEEPENING LOW PRESSURE SYSTEM LIFTS NORTH THROUGH THE GREAT LAKES
REGION.

IMPACT WEATHER APPEARS LIKELY FOR LATE MONDAY NIGHT AND TUESDAY
FEATURING SLIPPERY ROADS AND REDUCED VISIBILITIES. TEMPERATURES FOR
THE MORNING COMMUTE TIME ARE EXPECTED TO BE BELOW FREEZING WITH LAKE
SNOWS IN PROGRESS. ANY STANDING WATER FROM THE PREVIOUS RAIN AND
MELTING SNOW SHOULD FREEZE UP WITH SOME NEW SNOW ACCUMULATIONS
LIKELY ON TOP OF THAT. BRISK WESTERLY LOW LEVEL FLOW SHOULD SEND
HEAVIER SNOW BANDS WELL INLAND WITH AN I-96 OR I-94 CONVERGENCE BAND
POSSIBLE.

FORECAST CONFIDENCE IS CURRENTLY LOW FOR NEXT WEDNESDAY AND THURSDAY
AND THE PEAK HOLIDAY TRAVEL PERIOD. MODEL SOLUTIONS HAVE NOT BEEN
CONSISTENT FOR THIS PERIOD ALTHOUGH IT DOES LOOKS LIKE H5 TROUGHING
ALOFT WILL PROBABLY PERSIST. THIS IMPLIES A CONTINUED THREAT OF COLD
AIR INTRUSIONS FROM THE NORTHWEST WITH MORE BOUTS OF LAKE EFFECT
SNOWS POSSIBLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 659 AM EST FRI NOV 21 2014

WIDESPREAD CIGS OF 3000-4000 FT THIS MORNING WILL SCATTER OUT THIS
AFTERNOON. HOWEVER CLOUDS WILL RETURN QUICKLY LATER TONIGHT WITH
LIGHT FREEZING RAIN AND MVFR CONDITIONS BECOMING LIKELY AFTER 08Z.
SFC WINDS WILL INCREASE OUT OF THE SOUTH TO 10 TO 20 KTS TONIGHT.
MKG MAY ESCAPE THE FREEZING RAIN/ICING THREAT DUE TO A STRONG WIND
OFF THE WARMER WATERS OF LAKE MICHIGAN.


&&

.MARINE...
ISSUED AT 1255 PM EST FRI NOV 21 2014

HAVE ISSUED A GALE WARNING FOR TONIGHT FOR THE NORTHERN THIRD OF
OUR MARINE AREA BASED ON EXPECTED FREQUENT GUSTS ABOVE 35 KNOTS
IN STRENGTHENING WINDS FROM THE SOUTHWEST. THIS WOULD BE A LOW END
GALE EVENT...ESPECIALLY SINCE GUSTS MIGHT BE LIMITED BY LIMITED
WIND MOMENTUM TRANSFER IN STRONG WARM ADVECTION. NONETHELESS...WINDS
WILL BE STRONG ENOUGH TO QUICKLY BUILD WAVES OVERNIGHT. ISSUED A
SMALL CRAFT ADVISORY FOR THE SOUTHERN TWO THIRDS DURING THIS TIME.
A RESIDUAL SMALL CRAFT ADVISORY WILL BE IN EFFECT AREAWIDE FROM
SATURDAY MORNING THROUGH SUNDAY MORNING AS WINDS AND WAVES
GRADUALLY SUBSIDE.

MARINE FOG MAY ALSO BE AN ISSUE FROM SATURDAY NIGHT THROUGH
SUNDAY.

&&

.HYDROLOGY...
ISSUED AT 321 PM EST THU NOV 20 2014

WE ARE STILL MONITORING THE FLOOD THREAT OVER THE WEEKEND AS
AROUND A INCH OF RAIN IS EXPECTED TO FALL OVER OUR CURRENT SNOW
PACK. THE LATEST GUIDANCE FROM THE NCRFC INDICATES NONE OF OUR
RIVERS WILL RISE TO OR ABOVE FLOOD STAGE BUT WE MAY WELL HAVE SOME
MINOR URBAN AND SMALL STREAM FLOODING NONE THE LESS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST SATURDAY FOR
     MIZ037>040-043>046-050>052-056>059-064>067-071>074.

LM...SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 4 AM EST SUNDAY FOR
     LMZ848-849.

     GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST SATURDAY FOR
     LMZ848-849.

     SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 AM EST SUNDAY
     FOR LMZ844>847.

&&

$$

SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...WDM
MARINE...TJT





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