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000
FXUS63 KGRR 271731
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1231 PM EST TUE JAN 27 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 322 AM EST TUE JAN 27 2015

IT WILL REMAIN QUIET AND COOL TODAY THROUGH WEDNESDAY.  HIGHS WILL
BE IN THE 20S TODAY...THEN WARM TO AROUND 30 ON WEDNESDAY.  LOWS
TONIGHT WILL RANGE FROM THE SINGLE DIGITS ABOVE ZERO FOR INLAND
AREAS...TO THE TEENS ALONG THE LAKESHORE.

SNOW IS EXPECTED TO MOVE INTO THE REGION LATE WEDNESDAY NIGHT
THROUGH THURSDAY MORNING.  MOST AREAS SHOULD PICK AN INCH OR TWO OF
SNOW ACCUMULATION.  HOWEVER SOME AREAS SOUTH OF I-96 COULD SEE A
WINTRY MIX OF RAIN... SNOW...FREEZING RAIN AND SLEET.

THE REST OF THE WEEK AND INTO THE WEEKEND LOOKS RATHER QUIET AGAIN.
IT SHOULD REMAIN COLD...WITH HIGHS MAINLY IN THE 20S...ALTHOUGH
MONDAY COULD COOL FURTHER...WITH HIGHS ONLY IN THE TEENS.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 322 AM EST TUE JAN 27 2015

MAINLY FOCUS WAS ON THE CLIPPER SYSTEM FOR WEDNESDAY NIGHT AND
THURSDAY.  THIS SHOULD GIVE MOST OF THE CWA SNOW...BUT PCPN TYPE
ISSUES ARISE MAINLY SOUTH OF I-96.

THE CLIPPER REMAINS AN OPEN WAVE AS IT CROSSES OUR REGION....SO THE
PCPN WILL NOT LINGER...THEREFORE SIGNIFICANT ACCUMULATIONS ARE NOT
EXPECTED.  MUCH OF THE PCPN WILL OCCUR FROM MIDNIGHT WEDNESDAY NIGHT
THROUGH ABOUT NOON ON THURSDAY.  HOWEVER THE MAIN ISSUE IS HOW MUCH
WARM AIR ALOFT MOVES IN AHEAD OF THE SYSTEM...POSSIBLY PRODUCING A
WINTRY MIX.

DECENT AGREEMENT IN THE MODELS NOW SHOWING AROUND +2C H8 AIR MOVING
INTO AREAS SOUTH OF I-96 WEDNESDAY NIGHT.  THIS GRADUALLY GETS
PINCHED OFF THURSDAY MORNING AS THE SYSTEM OCCLUDES.  SO WILL
INTRODUCE MORE OF A MIX FOR THIS AREA.  SHOULD BE ENOUGH SHALLOW
COLD AIR NEAR THE SURFACE TO SUPPORT MOSTLY FREEZING RAIN WEDNESDAY
NIGHT...THEN SWITCHING TO AND RAIN/SNOW MIX THURSDAY MORNING...
BEFORE GOING BACK TO SNOW THURSDAY AFTERNOON AS THE SYSTEM EXITS.
FOR AREAS ALONG AND NORTH OF I-96 IT LOOKS LIKE MOSTLY SNOW WITH 1
TO 2 INCHES OF ACCUMULATION.  WE WILL NEED TO WATCH TRENDS FOR
POSSIBLE ADJUSTMENT TO PCPN TYPE ACROSS THE CWA AS THE SYSTEM WAS
ONLY JUST COMING ONTO THE BRITISH COLOMBIAN COAST EARLY THIS
MORNING.

PRIOR TO WEDNESDAY NIGHT IT WILL REMAIN QUIET AND COOL.  WE WILL SEE
INCREASING AMOUNTS OF SUNSHINE BY LATE THIS MORNING AS THE SYSTEM
TO OUR WEST CONTINUES TO SHEAR OUT.  CLEAR SKIES AND LIGHT WINDS
WILL PRODUCE SOME SINGLE DIGITS READINGS TONIGHT.  WEDNESDAY WILL
SEE MORE MID/HI CLOUDS...BUT SOME SUN SHOULD COME THROUGH AND WITH
WINDS TURNING TO THE SOUTH IT WILL BE A BIT WARMER.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 AM EST TUE JAN 27 2015

MAIN IMPACT WEATHER IN THE LONG TERM CENTERS ON CHANCES FOR SNOW
SATURDAY NIGHT AND SUNDAY...WITH COLDER AIR IN STORE FOR MONDAY...
ALBEIT NOTHING EXCESSIVE FOR THIS TIME OF YEAR. NO SIGNIFICANT
SNOWFALL IS EXPECTED IN THE EXTENDED PERIOD AT THIS TIME
ALTHOUGH A FEW INCHES ARE POSSIBLE LATE IN THE WEEKEND.

00Z GFS AND ECMWF ARE IN DECENT AGREEMENT REGARDING ARRIVAL OF A
VORT MAX BY SUNDAY NIGHT ALONG AN APPROACHING LONGWAVE TROUGH AS
SEEN AT H500. AHEAD OF THIS FEATURE...A BAROCLINIC ZONE IS FORECAST
TO MOVE THROUGH THE GREAT LAKES AS A WEAK LOW EVENTUALLY DEVELOPS
ALONG THE OHIO VALLEY. BEING ON THE NORTHERN PERIPHERY OF THIS
FEATURE WOULD YIELD LIGHT SNOW FOR THE REGION...PERHAPS A FEW INCHES
ON SUNDAY. WILL HAVE TO WATCH MODEL TRENDS WITH THIS SYSTEM AS A
WEAKER LOW/BAROCLINIC ZONE WOULD TEND TO KEEP MORE PRECIP SOUTH OF
OUR AREA WHEREAS A SHARPER H500 TROUGH WOULD HELP DEEPEN THE LOW A
BIT MORE...AND BRING IT FURTHER NW. FOR NOW WE HAVE GENERALLY 40-50%
POPS ACROSS THE AREA FOR SUNDAY WITH LIGHT ACCUMS POSSIBLE.

BEHIND THIS SYSTEM...H850 CAA IS SHOWN BY THE GFS AND ECMWF AS BOTH
MODELS SEEM TO BE CONVERGING ON A QUICK ARRIVAL AND DEPARTURE TO
ARCTIC AIR. COULD SEE H850 READINGS BETWEEN -20C AND -24C FOR MONDAY
WHICH WOULD YIELD HIGHS GENERALLY IN THE TEENS TO NEAR 20...COLD FOR
SURE BUT NOTHING REMARKABLE. THERE IS AT LEAST A CHANCE FOR LAKE
EFFECT SNOW SHOWERS MONDAY AND TUESDAY.

OUTSIDE OF THESE SYSTEMS...THERE IS A DECENT CHANCE FOR NW FLOW
LIGHT LAKE EFFECT SNOW SHOWERS FRIDAY IN SPITE OF A VERY SHALLOW
INVERSION OF AROUND 4K FT. THE DGZ IS SHOWN TO BE SATURATED AT MKG
AND LDM ALONG WITH SOME MARGINAL LIFT. ACCUMS WOULD BE MINOR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1231 PM EST TUE JAN 27 2015

LIMITED IMPACTS ARE EXPECTED TO AVIATION INTERESTS OVER THE NEXT
24 HOURS WITH MAINLY VFR CONDITIONS EXPECTED THROUGH 18Z WED. AREA
OF CIGS OF AROUND 6-8K FT THAT WAS OVER THE AREA EARLIER HAS MOVED
OUT/DISSIPATED...LEAVING MAINLY CLEAR SKIES AROUND THE AREA. SOME
LOCAL CIGS AROUND 2000-2500 FT FROM CLOUDS OFF OF LAKE HURON HAVE
AFFECTED KLAN AT TIMES. WE EXPECT THESE 2500 FT CLOUDS TO MOVE OUT
AS THE LOW LEVEL FLOW BACKS TO THE NORTH THIS AFTERNOON.

HIGH CLOUDS WILL MOVE IN OVERNIGHT TONIGHT. IT IS POSSIBLE FOR
SOME 2500 FT CLOUD COVER TO MOVE INTO KMKG LATE TONIGHT AS THE
FLOW BECOMES ONSHORE OFF OF LAKE MICHIGAN. CLOUD HEIGHTS WILL
GRADUALLY LOWER ON WED...BUT MAINLY VFR IS EXPECTED THROUGH 18Z.

&&

.HYDROLOGY...
ISSUED AT 1215 PM EST TUE JAN 27 2015

A FEW AREA RIVERS SHOWED MINOR FLUCTUATIONS OVER THE PAST 48 HOURS.
NONE OF THIS WAS TOO CONCERNING. THE ACTIVITY HAS SEEMED TO LEVEL
OFF AND STABILIZE FOR THE MOST PART. COLDER TEMPERATURES WILL HOLD
ON THROUGH MUCH OF THE WEEK WITH THE WARMEST CONDITIONS BEING FELT
THURSDAY...TO THE TUNE OF LOW TO MID 30S.

A COUPLE ROUNDS OF WINTRY PRECIPITATION ARE POSSIBLE. THE TWO MAIN
EVENTS ANTICIPATED ARE LATE WEDNESDAY INTO THURSDAY AND AGAIN BY
SUNDAY. MOISTURE WILL BE SPREAD OUT OVER TIME AND COLDER TEMPERATURES
DO NOT LOOK TO BE CAUSE FOR CONCERN. RIVERS WILL CONTINUE TO BE
MONITORED IN THE CASE THAT ANY FLUCTUATION DOES OCCUR.

&&

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

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...HOVING
AVIATION...NJJ
HYDROLOGY...JAM