Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 011142
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
642 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 326 AM EST SUN FEB 1 2015

A STRENGTHENING WINTER STORM WILL DUMP QUITE A BIT OF SNOW ON
SOUTHWEST LOWER MICHIGAN TODAY INTO TONIGHT. IN ADDITION...WINDS
WILL INCREASE AND CREATE NEAR BLIZZARD CONDITIONS AT TIMES FROM 1 PM
THROUGH 1 AM. THE HEAVIEST SNOW WILL FALL ALONG/SOUTH OF I-94 WHERE
OVER A FOOT OF SNOW IS EXPECTED. SNOW ACCUMULATIONS WILL TAPER OFF
THE FARTHER NORTH YOU GO BUT EVEN IN GRAND RAPIDS AND LANSING
SNOWFALL TOTALS WILL BE CLOSE TO 10 INCHES. REALIZE THOUGH THAT
THESE TOTALS WILL BE SPREAD OUT OVER 24 HOURS. SIGNIFICANT IMPACTS
ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT SO THOSE PLANNING
TO TRAVEL SHOULD ALLOW PLENTY OF TIME TO REACH THEIR DESTINATION.

HIGHS WILL REMAIN BELOW FREEZING THIS WEEK WITH TEMPERATURES IN THE
TEENS MONDAY AND THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

FORECAST CONCERNS DEAL WITH THE DEVELOPING WINTER STORM.

WE MADE A FEW CHANGES TO THE GOING HEADLINES. BASICALLY WE NUDGED
THE HEADLINES NORTH A ROW OF COUNTIES AND NOW INCLUDE GRAND RAPIDS
IN THE WINTER STORM WARNING.

THERE IS A LOT GOING FOR THIS STORM. FIRST IT/S A SLOW MOVING LOW
THAT IS STRENGTHENING AS IT MOVES ACROSS THE NORTHERN OHIO VALLEY.
SECOND...THERE IS A 60KT LLJ AHEAD OF THE LOW THAT BRINGS IN
ABUNDANT MOISTURE FROM THE GULF. THIRD...THE TROWAL NOW WORKS INTO
FAR SOUTHERN LOWER MICHIGAN PLACING A SWEET SPOT FOR HEAVY SNOW
ACROSS THE SOUTHERN CWA. FOURTH...THE DGZ...WHILE FAIRLY HIGH UP
INITIALLY...IS RATHER LARGE AND MORE IMPORTANTLY NEARLY ISOTHERMAL.
THAT/S SHOWN TO BE CONDUCIVE FOR SNOWFALL PRODUCTION. QPF OF 2/3 TO
3/4 OF AN INCH COUPLED WITH MIXING RATIOS NEAR 18:1 WOULD YIELD
SNOWFALL ACCUMULATIONS NORTH OF A FOOT OVER THE SOUTHERN CWA AND
CLOSE TO 10 INCHES ALONG I-96. EVEN THOUGH THIS IS A LONG DURATION
EVENT...AT LEAST 30 HOURS...WE FELT THIS JUSTIFIED ADDING ANOTHER
ROW OF COUNTIES TO THE WARNING. ADDITIONALLY...TRAVEL THIS EVENING
MAY BE GREATER THAN NORMAL DUE TO SUPER BOWL RELATED EVENTS.
ALSO...THE SLOWER NATURE OF THIS SYSTEM MEANS IT WILL LIKELY DRAG ON
INTO MONDAY MORNING AND AFFECT THE MONDAY MORNING COMMUTE.

COMPOUNDING THE SNOW WILL BE THE DEVELOPMENT OF STRONG WINDS THIS
AFTERNOON. BUFKIT WIND PROFILES SUGGEST WE/LL TAP INTO 35 KNOT WINDS
AS THE COLDER AIR WORKS INTO THE SYSTEM. THIS SHOULD RESULT IN
CONSIDERABLE BLOWING AND DRIFTING...AND MAYBE NEAR BLIZZARD
CONDITIONS AT TIMES. THE WINDS WILL DIE DOWN AFTER MIDNIGHT TONIGHT
BUT CLEANUP OF THE STORM WILL LAST WELL INTO MONDAY.

SNOW WILL DIMINISH MONDAY MORNING BUT MORE LIGHT SNOW IS POSSIBLE
TUESDAY AS A TROUGH MOVES THROUGH LOWER MICHIGAN.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

THE ARCTIC COLD FRONT WITH THE LONG ADVERTISED UPPER LEVEL PV
ANOMALY PUSH THROUGH THE AREA WEDNESDAY...WITH CHANCES FOR SNOW
WINDING DOWN WEDNESDAY EVENING. ESTIMATED SNOW TOTALS ENDING
WEDNESDAY EVENING THAT INCLUDE TUESDAY ARE STILL LOOKING AROUND 1-3
INCHES WITH LOCALLY HIGHER LAKESHORE AMOUNTS...SO LITTLE IMPACT
EXPECTED WITH THIS ROUND OF SNOW.

WIDESPREAD LOWS BELOW ZERO THURSDAY MORNING SEEM QUITE POSSIBLE
GIVEN LIGHT WINDS...A DRY AIRMASS...AND LIKELY SNOWPACK. MINIMAL
LAKE EFFECT SNOW SHOWER CONCERNS THURSDAY/FRIDAY WITH VERY DRY AND
COLD AIR IN PLACE. FAVORED ECMWF SHOWS THE NEXT COLD FRONT WITH
RESPECTABLE ATTENDANT MOISTURE PUSHING INTO THE AREA SATURDAY...SO
PROSPECTS FOR SNOW NEXT WEEKEND ARE INCREASING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 642 AM EST SUN FEB 1 2015

A SNOWSTORM WILL COMMENCE THIS MORNING AND LAST WELL INTO SUNDAY
NIGHT. PERSISTENT IFR/LIFR CATEGORIES IN SNOW AND BLOWING SNOW ARE
EXPECTED...ESPECIALLY BETWEEN 18Z TODAY AND 03Z MONDAY AT THE
AZO/BTL/JXN TERMINALS ALONG THE I-94 CORRIDOR. WIND GUSTS FROM
THE NORTHEAST TO 30 KNOTS WILL BECOME MORE LIKELY BY AFTERNOON
WHICH WILL FURTHER REDUCE VISIBILITIES IN BLOWING SNOW. LIGHT RIME
ICING WILL BE POSSIBLE GENERALLY BELOW 2000 FT AGL.

&&

.HYDROLOGY...
ISSUED AT 326 AM EST SUN FEB 1 2015

WE`RE LIKELY TO SEE ICE FORMATION THIS WEEK WITH BELOW FREEZING
TEMPERATURES EXPECTED THROUGHOUT THE WEEK. RIVER LEVEL FLUCTUATIONS
MAY DEVELOP AS A RESULT OF ICE BUILDUP.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ056>059-
     064>067-071>074.

     WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ037>040-
     043>046-050>052.

LM...NONE.
&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...04





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