Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 231154
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
654 AM EST FRI JAN 23 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 AM EST FRI JAN 23 2015

FAIR WEATHER WILL CONTINUE TODAY THROUGH SATURDAY BEFORE AN
ALBERTA CLIPPER BRINGS SOME SNOW FOR SUNDAY. COLDER AIR WILL MOVE
IN BEHIND THE CLIPPER SYSTEM FOR EARLY NEXT WEEK WHEN HIGH
TEMPERATURES WILL STRUGGLE TO REACH THE LOWER 20S MONDAY AND TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 300 AM EST FRI JAN 23 2015

A CONSENSUS OF LATEST 00Z GUIDANCE CONTINUES TO INDICATE THAT A
CLIPPER SYSTEM WILL MOVE THROUGH SUNDAY AND BRING POTENTIAL FOR
AROUND 2 TO 4 INCHES OF SNOW TO OUR SOUTHERN FCST AREA (MAINLY SOUTH
OF I-96). MOST OF THE SNOW WILL FALL FROM 12Z SUN THROUGH 00Z MON.

IT IS NOTED THAT THE 00Z ECMWF HAS TRENDED FURTHER SOUTH SUGGESTING
THAT VERY LITTLE SNOW WOULD FALL NORTH OF I-96. AN OVERALL SHORT
RANGE GUIDANCE CONSENSUS ALSO FAVORS OUR SOUTHERN FCST AREA FOR
ACCUMULATING SNOW GIVEN THE LOW TRACK. THEREFORE WE HAVE LOWERED
POPS AND FCST SNOW ACCUMS NEAR TO NORTH OF I-96 FOR SUNDAY
ACCORDINGLY.

IN THE NEARER TERM TRANQUIL WX WILL CONTINUE TODAY WITH PARTLY
SUNNY SKIES. THE COMBINATION OF A LITTLE SUN AND SW FLOW WILL HELP
TO BOOST MAX TEMPS INTO THE MID 30S. A FEW VERY LIGHT SNOW SHOWERS
OR FLURRIES ARE EXPECTED LATE TONIGHT INTO SATURDAY BUT WITH VERY
LITTLE TO NO SNOW ACCUMULATION.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM EST FRI JAN 23 2015

TO START THE PERIOD...THE BACK EDGE OF THE DEPARTING STORM MAY
SUPPORT A RISK FOR SNOW SUNDAY NIGHT ESPECIALLY TOWARD THE JACKSON
AREA.  WILL KEEP POPS RELATIVELY HIGH FOR THAT REGION. I DID TREND
TEMPERATURES LOWER FOR SUNDAY NIGHT WITH SOME FRESH SNOW AND THE LOW
LEVEL THERMAL TROUGH BUILDING IN FROM THE NORTH.

SHOULD BE A COLD PERIOD MONDAY INTO TUESDAY AS THE ARCTIC AIRMASS
PREVAILS.  WILL KEEP TEMPERATURES BELOW NORMAL FOR THIS PERIOD.
WARM AIR ADVECTION SHOWS UP BY THE END OF TUESDAY.  LOW POPS FOR
THIS TIMEFRAME AS THE DRY AIRMASS PREVAILS AND THE LIMITED LAKE
EFFECT POTENTIAL WITH OFFSHORE FLOW.  TUESDAY NIGHT THE WIND TURNS
SOUTHWEST AND THAT COULD SUPPORT LAKE EFFECT ESPECIALLY WEST OF
GRAND RAPIDS. HOWEVER THE INVERSION HIGHS ARE SHOWN TO BE LOW.  THUS
WILL NOT FEATURE HIGH POPS AT THIS TIME.

OVERALL THE ARCTIC AIR IS SHOWN TO DEPART SOONER AS WE GO THROUGH
WEDNESDAY.  I WILL BUMP UP TEMPERATURES SLIGHTLY CONSIDERING THIS
TREND.  WITH MID  LEVEL RIDGING...IT LOOKS LIKE GENERALLY DRY
WEATHER WILL PREVAIL.  A WEAKENING SURFACE TROUGH ARRIVES THURSDAY.
WITH LIMITED MOISTURE AND LIFT...THE RISK FOR ACCUMULATING SNOW
APPEARS LOW AT THIS TIME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM EST FRI JAN 23 2015

THIS SET OF TAFS FEATURES MORE PESSIMISTIC CEILINGS AND
VISIBILITIES. LOW CLOUDS WITH MVFR CEILINGS UNDER 2000 FT HAVE
SETTLED IN. WATCHING SATELLITE TRENDS...THE LOW CLOUDS WILL LIKELY
PERSIST THROUGH THE AFTERNOON. I ADDED IFR TO KMKG AS THE LOW
LEVEL WINDS MAY LOWER THE CEILINGS THERE.

A WEAKENING AREA OF SNOW WILL MOVE IN FROM THE NORTHWEST LATER IN
THE DAY. KMKG SHOULD SEE SOME SNOW RESTRICTING THE
VISIBILITY...HOWEVER BY THE TIME IT REACHES KJXN...PERHAPS ONLY
SOME FLURRIES CAN BE EXPECTED. SOMETIME FREEZING DRIZZLE OCCURS IN
THESE SCENARIOS. WHILE NOT IN THE FORECAST...THIS IS SOMETHING
THAT SHOULD BE MONITORED CLOSELY. ICING IS LIKELY IN THE
CLOUDS...ESPECIALLY AFTER MIDNIGHT TONIGHT.

IFR CEILINGS COULD BECOME MORE WIDESPREAD TONIGHT AS A COLD FRONT
TRACKS IN WHICH SUPPORTS LOWER CEILINGS.

&&

.HYDROLOGY...
ISSUED AT 321 PM EST THU JAN 22 2015

ALL GAUGES SHOW RIVER LEVELS BELOW BANKFULL. WILL CONTINUE
MONITORING FOR POTENTIAL ICE JAMS WHICH CAN CAUSE WATER LEVEL RISE
AT ANY TIME. SIGNIFICANT ICE JAM FLOODING IS UNLIKELY FOR THE TIME
BEING. A SMALL AMOUNT OF ICE MELT MAY OCCUR WITH MILDER TEMPERATURES
FRIDAY AND SATURDAY BEFORE COLDER AIR ARRIVES NEXT WEEK.

&&

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

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MJS
AVIATION...MJS
HYDROLOGY...CAS






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