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000
FXUS63 KGRR 300501
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1201 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 915 PM EST THU JAN 29 2015

FAIRLY STRONG SHORT WAVE SEEN ON WV IMAGERY OVER NRN WISCONSIN HAS
CAUSED A FLARE UP OF SHSN ACTIVITY ACROSS THE WESTERN CWA THIS
EVENING. VSBYS HAVE FALLEN TO NEAR A MILE AT SOME LOCATIONS AS
SNOW BANDS MOVE SOUTH FROM LAKE SUPERIOR. SHSN SHOULD DIMINISH
SOME AFTER 06Z AS THE WAVE MOVES EAST. UPDATED GRIDS OVER THE
WESTERN CWA TO REFLECT HIGHER POPS THIS EVENING.

UPDATE ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1159 PM EST THU JAN 29 2015

THE TREND OVERNIGHT WILL BE FOR VFR CONDITIONS TO BECOME MORE
WIDESPREAD DUE TO THE ARRIVAL OF A DRIER (AND MUCH COLDER) AIR
MASS FROM THE NORTH. HOWEVER MKG MAY SEE OCNL IFR VSBYS CONTINUE AS
LAKE EFFECT SNOW SHOWERS CLIP THE COAST.

SNOW SHOWERS INLAND FROM LAKE MICHIGAN AT MIDNIGHT ARE EXPECTED
TO END BY 4 AM OR SO AND SEVERAL TERMINALS MAY ACTUALLY SEE SKIES
BECOME SCATTERED BEFORE DAYBREAK. ANY CLEARING THAT TAKES PLACE
LATE TONIGHT AND FRIDAY MORNING WILL PROBABLY FILL BACK IN ON
FRIDAY AFTERNOON. HOWEVER CLOUD BASES SHOULD BE MOSTLY VFR.

GUSTY NORTH-NORTHWEST WINDS FOR A FEW MORE HOURS WILL RESULT IN
CONTINUED LOW LEVEL TURBULENCE... BUT THE WINDS WILL DIMINISH TO
AROUND 10 KTS VERY LATE TONIGHT INTO FRIDAY.

&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

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

$$

UPDATE...93
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM