Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 220449
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1149 PM EST WED JAN 21 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 305 PM EST WED JAN 21 2015

SNOW WILL TAPER OFF THIS EVENING AS A CLIPPER MOVES AWAY. GENERALLY
FAIR WEATHER IS EXPECTED UNTIL SUNDAY WHEN ANOTHER CLIPPER WILL
BRING MORE LIGHT SNOW.

&&

.UPDATE...
ISSUED AT 535 PM EST WED JAN 21 2015

INCREASED POPS A BIT OVER THE NORTHERN CWA WHERE LIGHT SNOW
CONTINUES TO DEVELOP IN VICINITY OF SHEARING TROUGH. THE NORTH SIDE
OF THE PCPN SHIELD IS SLOWLY SINKING SOUTH AND THIS TREND SHOULD
CONTINUE OVERNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 305 PM EST WED JAN 21 2015

MESOSCALE SNOW BANDS ARE CURRENTLY WEAKENING AS THEY PIVOT ACROSS
CENTRAL LOWER MICHIGAN. ELONGATED SFC LOW IS CENTERED SOUTH OF THE
FORECAST AREA AND IS MOVING EAST. AN AREA OF MID LEVEL F-GEN
FORCING WILL ALSO BE TRANSLATING EAST THIS EVENING. SOME SNOW
SHOWERS ARE EXPECTED TO LINGER NEAR THE LAKE MICHIGAN COAST
OVERNIGHT AS LOW LEVEL FLOW GOES NORTHWEST AND LAKE ENHANCED BANDS
CURRENTLY OVER THE LAKE MOVE ONSHORE. THESE SHOULD NOT AMOUNT TO
MUCH AS INVERSION HEIGHTS FALL BLO 5 KFT WHEN THE SNOW MOVES
ONSHORE.

THE NEXT CLIPPER TRACKS NORTH OF MICHIGAN ON FRIDAY WITH A
TRAILING COLD FRONT ACROSS NORTHERN LOWER MICHIGAN FRIDAY NIGHT.
SOME LIGHT SNOW IS POSSIBLE ALONG THE FRONT BUT AT THIS POINT IT
LOOKS LIKE PRETTY INSIGNIFICANT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 305 PM EST WED JAN 21 2015

THE MAIN FOCUS DURING THE LONG TERM IS A CLIPPER THAT WILL AFFECT
SOUTHWEST LOWER MICHIGAN LATE SATURDAY NIGHT AND MUCH OF SUNDAY. IT
DOESN/T LOOK LIKE A HEAVY SNOW EVENT BUT MAY BE PLOWABLE WITH 2-4
INCHES ACCUMULATION.

A COLD FRONT WILL DROP SOUTH FROM NORTHERN LOWER SATURDAY NIGHT AND
THE CLIPPER WILL INTERACT WITH THE BAROCLINIC ZONE SUNDAY. IT/S
POSSIBLE THERE COULD BE LOCALIZED HIGHER ACCUMS WITH THAT SYSTEM BY
LATE SUNDAY.

WE/LL HAVE A COUPLE OF DAYS OF MAINLY DRY WX AFTER THAT BEFORE
ANOTHER WEAKER CLIPPER MOVES OVER THE CWA LATE TUESDAY. MODELS SHOW
THAT SYSTEM WEAKENING AS IT MOVES SOUTHEAST.

SATURDAY WILL BE THE WARMEST DAY WITH HIGHS IN THE MID 30S. AFTER
THE CLIPPER MOVES THROUGH WE/LL SEE HIGHS IN THE 25 TO 30 DEGREE
RANGE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1149 PM EST WED JAN 21 2015

ONE LAST BAND OF LIGHT SNOW WILL CONTINUE TO SPREAD ACROSS THE
WESTERN TAF SITES EARLY THIS MORNING AS A WEAK LAKE EFFECT EVENT
BEGINNING BUT DRY AIR COMING DOWN FROM THE NORTH SHOULD END THE SNOW
BY 09Z. IN FACT...THERE MAY EVEN BE A FEW HOURS WHERE THE LOW
CLOUDS ACTUALLY SCATTER OUT TOTALLY IN THE 09Z TO 15Z TIME FRAME
(CAN BE SEEN ON IR LOOP DROPPING SOUTH NEAR TVC AREA) BUT I WAS NOT
SURE ENOUGH ACTUALLY PUT THAT IN THE TAFS. MVFR CIGS WILL PREVAIL
THROUGH THE DAY TIME HOURS OF THURSDAY BUT WINDS WILL BE LIGHT.

&&

.HYDROLOGY...
ISSUED AT 328 PM EST WED JAN 21 2015

THE ONLY CONCERN AT THIS TIME IS THE ICE JAM POTENTIAL AROUND THE
AREA. MILD WEATHER OVER THE NEXT FEW DAYS COULD POTENTIALLY ALLOW
SOME ICE TO BREAK UP AND START TO MOVE. IT APPEARS ICE IS AFFECTING
THE GAGE AT EVART...BUT NO OTHER SPECIFIC CONCERNS AT THIS TIME.

OTHER THAN ICE JAMS...WE EXPECT NO SIGNIFICANT AMOUNT OF RUN OFF
INTO THE RIVERS OVER THE NEXT WEEK. WE COULD BE LOOKING AT A COLD
PERIOD LATE NEXT WEEK THAT COULD HELP TO INCREASE ICE FORMATION.

&&

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

$$

UPDATE...93
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...WDM
HYDROLOGY...NJJ






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