Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 030203
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
903 PM EST TUE FEB 2 2016

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 330 PM EST TUE FEB 2 2016

LOW PRESSURE WILL BRING RAIN AND MIXED PRECIPITATION TO LOWER
MICHIGAN TONIGHT. THE LOW MOVES AWAY ON WEDNESDAY BUT LINGERING
RAIN AND SNOW SHOWERS WILL REMAIN. COLDER AIR FOLLOWS FOR WEDNESDAY
NIGHT AND THURSDAY WITH SOME LAKE EFFECT SNOW SHOWERS.

&&

.UPDATE...
ISSUED AT 903 PM EST TUE FEB 2 2016

WE HAVE CONTINUED THE WINTER WEATHER ADVISORY UP NORTH FOR THE
TIME BEING THIS EVENING. WE ANTICIPATE THAT IT WILL BE ABLE TO
EXPIRE ON TIME OR EVEN EARLY BASED ON OUR LATEST THINKING.

MANY AWOS SITES CONTINUE TO REPORT -SN THIS EVENING ACROSS THE
AREA...WHICH IS LIKELY IN ERROR DUE TO THE HAIL AND/OR WIND DRIVEN
RAIN AT THESE SITES. WE HAVE CONFIRMED THIS AT MAINLY LOCATIONS
FROM REPORTS ON THE GROUND THAT RAIN IS THE PREDOMINATE PCPN TYPE
AT THIS TIME.

MOST ALL SITES ARE ABOVE FREEZING ALONG U.S.-10...EXCEPT FOR
LEOTA WHICH WAS 31 DEGREES AT AROUND 0030Z. SOME OF THESE LOCALES
COULD SEE A LITTLE MORE FREEZING RAIN UNTIL THEY COME ABOVE
FREEZING...WHICH SHOULD BE IN THE NEXT COUPLE OF HOURS AS THE SFC
LOW APPROACHES.

OTHERWISE...THE RAIN AND STORMS WILL DIMINISH AS THE DRY SLOT
SPREADS ACROSS THE AREA OVER THE NEXT FEW HOURS. WE SHOULD THEN
SEE ONLY SOME DRIZZLE AND FOG THE REMAINDER OF THE NIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM EST TUE FEB 2 2016

NO SIGNIFICANT CHANGES MADE TO GOING FORECAST AS THE STORM APPEARS
TO BE ON TRACK. A STRONG DRY WEDGE AROUND 850 MB SEEN ON LAPS
SOUNDINGS THIS AFTERNOON RESULTED IN PLENTY OF VIRGA EARLIER
BEFORE IT MOISTENED UP AND SOME SNOW AND SLEET REACHED THE GROUND.
THE PRECIP HAS GONE OVER TO RAIN AS OF 20Z AT GRR...MKG AND POINTS
SOUTH. THE MIX WILL CONTINUE ACROSS THE NORTHERN TIER THROUGH THE
EVENING WITH A COUPLE INCHES OF WET SNOW EXPECTED ACROSS THE
HIGHER GROUND OF NORTHERN OSCEOLA AND CLARE COUNTIES.

THE DRY SLOT MOVES IN AFTER MIDNIGHT AND PRECIPITATION SHOULD
TAPER OFF TO DRIZZLE. THERE IS A BREAK IN THE STEADIER PRECIP
UNTIL LATER WED MORNING WHEN THE NORTHWEST FORECAST AREA MAY BE
CLIPPED BY THE DEFORMATION ZONE SHOWERS RAIN SHOWERS MIZ WITH SNOW
DURING THE AFTERNOON AS COLD AIR WRAPS BACK IN. LAKE EFFECT SNOW
SHOWERS EXPECTED TO BRING LIGHT ACCUMS WEDNESDAY NIGHT IN
CYCLONIC FLOW WITH INVERSION HEIGHTS AROUND 5 KFT.

THERMAL TROUGH AXIS MOVES EAST ON THURSDAY BUT A WEAK CLIPPER WILL
MOVE IN THURSDAY NIGHT AND INVERSION HEIGHTS GO BACK UP TO AROUND
10 KFT...ALLOWING MORE SNOW ACCUMS.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 PM EST TUE FEB 2 2016

A WEAK COLD FRONT SHOULD BE PASSING THROUGH THE AREA FRIDAY MORNING.
WITH THIS AND H8 TEMPS OF -10C TO -12C...IT SHOULD BE ENOUGH TO
SUPPORT LIGHT LAKE ENHANCED SNOW SHOWERS.  ADDED THESE TO THE
FORECAST.

THEN WE SHOULD MOVE INTO A QUIETER PERIOD AS HIGH PRESSURE AND WARM
ADVECTION ARRIVES FRIDAY NIGHT INTO THE WEEKEND.  A WEAK FRONT DOES
TRY TO PUSH DOWN FROM THE NORTH SATURDAY WHICH MAY SUPPORT SOME
LIGHT...INSIGNIFICANT SNOW.

BETTER CHANCES OF SNOW MOVES IN WITH A CLIPPER SYSTEM BY SUNDAY
NIGHT.  AT THIS POINT IT DOES NOT APPEAR TO BE THE TYPICAL CLIPPER
THAT SWEEPS QUICKLY THROUGH.  INSTEAD IT IS ASSOCIATED WITH AN UPPER
LOW THAT RESULTS IN A MUCH SLOWER MOVING SYSTEM.  WHILE IT ENTERS
THE GREAT LAKES SUNDAY NIGHT...IT ONLY MOVES ACROSS CENTRAL LOWER
MICHIGAN LATE MONDAY.  SO THIS COULD PRODUCE A PROLONG PERIOD OF
SNOW.  AS A SIDE NOTE...THE MODELS ARE A BIT COOLER WITH THIS SYSTEM
AND I REMOVED ANY MENTION OF RAIN ...KEEPING PCPN TYPE ALL SNOW.
COLDER AIR SWEEPS IN BEHIND THE SYSTEM FOR MONDAY NIGHT AND TUESDAY
WHICH SHOULD HELP TO GET THE LAKE EFFECT GOING AGAIN.  SO AS IT
APPEARS NOW IT LOOKS MORE WINTRY AS WE GET INTO NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 736 PM EST TUE FEB 2 2016

VERY CHANGEABLE WEATHER IS EXPECTED THE NEXT 24 HOURS...AS A LOW
PRESSURE SYSTEM MOVES THROUGH THE GREAT LAKES REGION. STRONG
EASTERLY WINDS AND THUNDERSTORMS ARE EXPECTED THROUGH ABOUT
05Z...NORTH OF A WARM FRONT. CEILINGS AND VISIBILITIES WILL BE
TRENDING DOWN STEADILY THROUGH THE EVENING AND HEAD FOR IFR AND
LIFR CONDITIONS AFTER 07Z...WHEN THE LOW WILL BE MOVING RIGHT
THROUGH THE AREA. AS THE LOW MOVES THROUGH...THE WINDS WILL BECOME
MUCH LIGHTER...LESS THAN 10 KNOTS...AND THE CEILINGS AND
VISIBILITIES WILL DROP BELOW 1000FT AND BELOW 3 MILES.

WINDS WILL RAMP UP ONCE AGAIN WEDNESDAY MORNING BETWEEN 12Z AND
15Z OUT OF THE SOUTHWEST. WINDS OF 12-28 KNOTS ARE EXPECTED
WEDNESDAY FROM 220-250 DEGREES. CONDITIONS SHOULD IMPROVE TO MVFR
WEDNESDAY AFTERNOON.

REGARDING PRECIPITATION...THE RAIN WILL END FOR THE MOST PART
AFTER 07Z OR SO. WE SHOULD BE MAINLY DRY OVERNIGHT AND THROUGH
WEDNESDAY MORNING...WITH SOME RAIN AND SNOW POSSIBLE WEDNESDAY
AFTERNOON.


&&

.MARINE...
ISSUED AT 330 PM EST TUE FEB 2 2016

THE GALE WARNING IS DOWNGRADED TO A SMALL CRAFT ADVISORY AS WINDS
ARE EXPECTED TO CONTINUE TO REMAIN BLO 34 KNOTS. WINDS AND WAVES
WILL DIMINISH AFTER MIDNIGHT.


&&

.HYDROLOGY...
ISSUED AT 235 PM EST TUE FEB 2 2016

MINOR FLOODING IS POSSIBLE LATER THIS WEEK... ESPECIALLY IN
LOWLAND AREAS NEAR RIVERS. SOME RIVERS MAY EXCEED BANKFULL DUE TO
SNOW MELT AND PRECIPITATION FROM A STORM TODAY AND TONIGHT. STORM
TOTAL PRECIPITATION OF 0.50-1.00 INCHES IS POSSIBLE. PRECIPITATION
IS STILL EXPECTED TO BE A WINTRY MIX OR PLAIN RAIN. RIVER LEVEL
RISES ARE ESPECIALLY LIKELY FROM MIDWEEK THROUGH THE WEEKEND. RIVER
FLOOD ADVISORIES HAVE BEEN ISSUED FOR SYCAMORE CREEK AT HOLT...
MAPLE RIVER AT MAPLE RAPIDS AND GRAND RIVER AT IONIA.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ037>040.

LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR LMZ844>849.

&&

$$

UPDATE...NJJ
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...JK
AVIATION...DUKE
HYDROLOGY...63
MARINE...OSTUNO


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