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000
FXUS63 KGRR 282335
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
635 PM EST FRI FEB 28 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 PM EST FRI FEB 28 2014

MORE LIGHT SNOW IS EXPECTED OVER THE WEEKEND AND IT WILL REMAIN
COLD... BUT NOT QUITE AS BITTER AS THE LAST COUPLE DAYS.

NEW SNOWFALL OF 2 TO 4 INCHES IS EXPECTED TONIGHT AND SATURDAY
MORNING NORTH AND WEST OF GRAND RAPIDS... WITH AN INCH OR LESS FOR
GRAND RAPIDS AND AREAS TO THE SOUTH AND EAST.

ON SATURDAY NIGHT 1 TO 4 INCHES OF NEW SNOW IS FORECAST FOR AREAS
ALONG AND SOUTH OF A LINE FROM MUSKEGON TO ALMA... WITH AN INCH OR
LESS TO THE NORTH.

GRADUALLY MODERATING TEMPERATURES ARE EXPECTED NEXT WEEK AND HIGHS
ABOVE FREEZING ARE POSSIBLE BY THE END OF NEXT WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 329 PM EST FRI FEB 28 2014

THIS WEEKEND WILL FEATURE A COUPLE OF LIGHT SNOW EVENTS... HIGHLY
INFLUENCED BY MID LEVEL FRONTOGENETICAL FORCING. THE FGEN FORCING IS
BEING DRIVEN BY AN ELONGATED WEST TO EAST UPPER LEVEL JET STREAK
ALONG THE U.S./CANADIAN BORDER ON THE SRN PERIPHERY OF THE HUDSON
BAY VORTEX. STRONGER/SMALLER JETLETS WITHIN THIS BELT OF STRONGER
WINDS WILL BRING PERIODS OF ENHANCED UPPER LEVEL DIVERGENCE AND FGEN
FORCING.

THE FIRST EVENT IS TONIGHT INTO SATURDAY MORNING AS THE BAND OF
LOCALLY HEAVY SNOW CURRENTLY BREAKING OUT ACROSS SE MN AND CENTRAL
WI EXPANDS/SPREADS E/NE INTO NRN LWR MI.  THIS ACTIVITY IS ALSO
BEING AIDED BY DECENT LOW LEVEL CONVERGENCE ASSOCIATED WITH AN
INVERTED SFC TROUGH.

AS THIS INCOMING SNOW IMPACTS AREAS NORTH AND WEST OF GRR TONIGHT...
SOUTHWEST FLOW LAKE ENHANCEMENT WILL ALSO COME INTO TO PLAY AND WE
MAY LOOKING AT SOME LOCALIZED 4-5 INCH AMOUNTS AROUND LUDINGTON AND
PENTWATER. WAS NOT CONFIDENT ENOUGH TO GO WITH AN ADVISORY BUT THIS
WILL NEED TO BE CLOSELY MONITORED THIS EVENING.

THE LOW LEVEL SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL
BOUNDARY WILL LEAD TO RISING TEMPERATURES TONIGHT WITH MANY AREAS
CLIMBING INTO THE LOWER 20S BY DAYBREAK.

SNOW DIMINISHES SATURDAY MORNING AS THE FRONTAL BOUNDARY MOVES SOUTH
AND EAST OF GRR AND AS THE FIRST BOUT OF FGEN FORCING WEAKENS IN
FAVOR OF NEW DEVELOPMENT OVER IOWA. IT IS THIS PRECIP WHICH SPREADS
EAST INTO SRN LWR MI SATURDAY NIGHT.

THE SATURDAY NIGHT EVENT IS TRICKY BECAUSE BANDED PRECIP IS LIKELY
IN THE FGEN REGIME RATHER THAN BEING EVENLY DISTRIBUTED ACROSS A
BROAD AREA AS SOME OF THE GUIDANCE QPF PROGS MAY SUGGEST. THE NAM
MEANWHILE TYPICALLY OVERDOES QPF IN THESE STRONG FGEN SITUATIONS...
SO SHIED AWAY FROM ITS HEAVIER QPF AMOUNTS. BELIEVE A BROAD RANGE OF
1-4 IS THE MOST LIKELY SCENARIO ALTHOUGH WHERE THE 3-4 AMOUNTS SET
UP IS LOW CONFIDENCE ATTM.

TURNING QUIET BUT COLD SUNDAY AND SUNDAY NIGHT WITH WEAK NORTHERLY
LOW LEVEL FLOW AND SFC RIDGING. THE BIG SYSTEM OVER THE TN VALLEY
REGION STAYS SOUTH OF MI FOR THE MOST PART.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 329 PM EST FRI FEB 28 2014

THE LONG TERM WILL FEATURE A MODERATING TREND IN TEMPERATURES
THROUGH THE PERIOD WITH A COUPLE OF CHANCES OF SOME PCPN AS THE
UPPER JET ACROSS THE NRN U.S. BECOMES MORE ZONAL. IT LOOKS LIKE AT
THIS TIME THAT WE SHOULD NOT SEE ANY MAJOR STORM SYSTEMS AFFECT
LOWER MICHIGAN THROUGH THE PERIOD.

WE WILL START OUT THE LONG TERM WITH A FAIRLY STRONG RIDGE OF HIGH
PRESSURE IN CONTROL OF THE WX. THE RIDGE SHOULD BE WEST OF THE AREA
ON MON MORNING. THIS WILL PROVIDE THE AREA WITH A MAINLY NRLY FLOW.
LAKE EFFECT SHOULD BE OFFSHORE AND WE SHOULD SEE GENERALLY DRY
CONDITIONS. WE CAN EXPECT A FAIRLY COLD DAY ON MON WITH HIGHS LUCKY
TO MAKE THE MID TEENS. MON NIGHT LOOKS TO BE A COLD ONE WITH LIGHT
FLOW OVER THE AREA AND A LACK OF CLOUD COVER EXPECTED. ANOTHER NIGHT
OF BELOW ZERO TEMPS LOOKS VERY POSSIBLE.

IT DOES LOOK LIKE THE AREA HAS A CHC OF SOME LIGHT SNOW FOR MAINLY
THE DAY ON TUE. WE WILL SEE A SHORT WAVE DIVE SE ACROSS THE REGION.
THIS WAVE LOOKS TO BE RATHER WEAK AND WILL BE MOISTURE STARVED AS IT
WILL NOT HAVE ANY GULF MOISTURE TO WORK WITH. IT WILL REINFORCE THE
COOLER AIR FOR ONE MORE DAY...BUT NOT BE TOO BRUTAL.

THE REMAINDER OF THE WEEK LOOKS LIKE WE WILL SEE A MILDER TREND TAKE
PLACE FOR THE AREA. THIS WILL ESPECIALLY BE THE CASE FOR THU AND
FRI. HIGH PRESSURE OVER THE AREA ON WED WILL KEEP TEMP ADVECTION
RATHER NEUTRAL. WE WILL SEE THE HIGH SLIP EAST ON THU...AND ALLOW
FOR BETTER SW FLOW TO KICK IN. THE LEADING EDGE OF THIS TEMP ADV
COULD BRING SOME LIGHT SNOW TO THE AREA. ANY SNOW LOOKS TO BE A
QUICK BURST. TEMPS AT H850 THEN GO ABOVE FREEZING BY FRI. THIS
SHOULD ALLOW TEMPS TO WARM AT LEAST INTO THE 30S...IF NOT INTO THE
40S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 635 PM EST FRI FEB 28 2014

DID NOT CHANGE INHERITED TAFS SIGNIFICANTLY EXCEPT TO BRING WINDS
AROUND TO THE NORTHWEST A LITTLE STRONGER AND EARLIER ON SATURDAY
MORNING. TIMING FOR PRECIPITATION STILL LOOKS GOOD. VISIBILITIES
COULD DROP BELOW A MILE AT MKG IN THE 06Z TIME FRAME AS FORECAST
MODELS INDICATE AN INTENSE SNOWBAND POSSIBLY SETTING UP NEAR THE
LAKESHORE. AFTERWARDS...VISIBILITIES SHOULD IMPROVE RATHER QUICKLY
WITH THE WIND SHIFT TO THE NORTHWEST. CEILINGS DURING THE DAY
SATURDAY ARE A BIT UNCERTAIN. A POSSIBLE CHANGE TO THE UPCOMING
06Z TAF UPDATES WOULD BE TO LOWER CIGS TO FUEL ALTERNATE LEVELS
/BELOW 2000 FT AGL/ IF FORECAST MODELS CONTINUE TO ADVERTISE THIS.

&&

.HYDROLOGY...
ISSUED AT 329 PM EST FRI FEB 28 2014

STABLE ICE DEVELOPMENT WILL CONTINUE DUE TO COLD WEATHER. THE ICE
JAM THREAT IS LOW AND THERE IS NO CURRENT INDICATIONS OF ANY ICE
JAMS ON THE RIVER NETWORK. RIVERS LEVELS ARE STEADY ACROSS THE AREA.

AT SOME STATIONS... THE SYSTEMS USED TO SENSE WATER STAGE ARE
SUSCEPTIBLE TO ERRONEOUS READINGS DURING PERIODS OF EXTREME COLD
TEMPERATURES.  STAGE HYDROGRAPHS DURING SUCH TIMES SHOW RAPID
FLUCTUATIONS IN WATER LEVELS AND SUBSEQUENT RAPID RETURN TO PREVIOUS
LEVELS WHEN SLIGHTLY WARMER TEMPERATURES RETURN.

&&

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

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...TJT
HYDROLOGY...63