Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 030501
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1201 AM EST TUE MAR 3 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 PM EST MON MAR 2 2015

A QUICK MOVING SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO
SOUTHWEST LOWER MICHIGAN ON TUESDAY. SNOW WILL SPREAD INTO THE
AREA AROUND OR SHORTLY AFTER DAYBREAK ON TUESDAY. THE SNOW WILL
MIX WITH SLEET AND THEN CHANGE OVER TO RAIN AND FREEZING RAIN FOR
LOCATIONS ALONG AND SOUTH OF THE INTERSTATE 96 CORRIDOR. SNOW
ACCUMULATIONS WILL RANGE FROM 2-4 INCHES TOWARDS U.S. 10 TO 1-2
INCHES TOWARDS INTERSTATE 94. ICE ACCUMULATIONS OF ONE TO TWO
TENTHS OF AN INCH FROM FREEZING RAIN WILL BE POSSIBLE ALONG AND
SOUTH OF INTERSTATE 96. THE PRECIPITATION WILL WIND DOWN QUICKLY
IN THE AFTERNOON AND EVENING WITH FREEZING DRIZZLE PERSISTING
AFTER SUNSET POTENTIALLY. COLDER AIR WILL SWEEP INTO THE AREA FOR
WEDNESDAY AND THURSDAY WITH LAKE EFFECT SNOW SHOWERS.

&&

.UPDATE...
ISSUED AT 902 PM EST MON MAR 2 2015

THE GOING FORECAST IS ON TRACK. NO CHANGE TO THE HEADLINES. CLOUDS
WILL CONTINUE TO OVERSPREAD THE CWA TONIGHT WITH PCPN DEVELOPING
TOWARD MORNING.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 329 PM EST MON MAR 2 2015

FOCUS IS SQUARELY ON THE SYSTEM FOR TOMORROW AS IT WILL BRING A
MIX OF PRECIPITATION TO THE AREA. WINTER WEATHER ADVISORY WILL BE
ISSUED FOR THE ENTIRE AREA FROM 700 AM THROUGH 800 PM ON TUESDAY.

SYSTEM IS A QUICK HITTING BURST OF WARM AIR ADVECTION
PRECIPITATION ASSOCIATED WITH A SHORTWAVE THAT IS JUST STARTING TO
COME ASHORE IN SOUTHERN CALIFORNIA. THE SHORTWAVE IS BEING BOOTED
OUT FROM AN UPSTREAM KICKER DROPPING DOWN THE WEST COAST OF THE
U.S. THE SHORTWAVE WILL RIDE A 150-170KT JET NORTHEAST TOWARD THE
GREAT LAKES TONIGHT.

SNOW SHOULD SPREAD IN AROUND OR JUST AFTER 12Z ACROSS THE AREA. A
LLJ ON THE ORDER OF 45-60KTS WILL BRING A BURST OF PRECIPITATION
TO THE AREA DURING THE DAY ON TUESDAY. STRONG ISENTROPIC LIFT IS
SEEN ON THE 290K SURFACE. THE PRECIP WILL CONTAIN CONVECTIVE
POCKETS GIVEN THE STRONG WARM AIR ADVECTION. FEEL THE BULK OF THE
PRECIP WILL FALL BETWEEN 700 AM AND 400 PM. THE PRECIP WILL BECOME
SCATTERED AND TAPER OFF AFTER 400 PM...TRENDING TOWARDS DRIZZLE
AND FREEZING DRIZZLE DURING THE EVENING HOURS. THE ADVISORY MAY
NEED TO BE EXTENDED FURTHER INTO THE EVENING HOURS OF TUESDAY
DEPENDING ON THE EXTENT OF THE FREEZING DRIZZLE TOMORROW EVENING.

FEEL WE ARE LOOKING AT SNOWFALL ACCUMULATIONS OF 2-4 ACROSS
CENTRAL LOWER...1-3 ACROSS THE I-96 CORRIDOR AND AREAS JUST NORTH
OF THERE AND AROUND AN INCH OR SO IN THE SOUTH. IN TERMS OF
ICING...THINKING A TENTH OF AN INCH IS POSSIBLE FROM I-96 OFF TO
THE SOUTH. FEEL THERE MAY BE A FEW POCKETS OF 0.10 TO 0.20 IN
AREAS THAT RECEIVE CONVECTIVE BURSTS OF PRECIP.

MAIN IMPACT TO KEEP AN EYE ON IS THE ICING REALLY...AS THE SNOW
TOTALS ARE NOT GOING TO BE IMPRESSIVE. THERE IS SOME QUESTION JUST
HOW WARM WE GET TOMORROW GIVEN A DROP IN TEMPS TONIGHT BEFORE
THICK CLOUDS ROLL IN. THE BULK OF THE PRECIP WILL FALL BEFORE THE
STRONG SURFACE WARM AIR ADVECTION TAKES HOLD IN THE MID AFTERNOON
THROUGH EVENING HOURS. ICING ON SECONDARY ROADS THAT ARE COVERED
WITH SNOW AND ICE ALREADY IS A CONCERN. FEEL WE COULD SEE SOME
MIXY PRECIP ALL THE WAY NORTH TO THE OCEANA TO ISABELLA ROW OF
COUNTIES.

WINDS WILL RAMP UP TOMORROW AFTERNOON AS WELL WITH GUSTS IN THE
AFTERNOON AND EVENING TO 30-40 MPH POTENTIALLY. THIS WIND WITH
ICING OF A TENTH OF AN INCH OR SO COULD RESULT IN SOME ISOLATED
POWER OUTAGES GIVEN ICY BRANCHES FALLING ONTO POWER LINES.

BEYOND THE TUESDAY SYSTEM COLD AIR WRAPS BACK INTO THE AREA WITH
THE -20C 850MB ISOTHERM PLUNGING THROUGH FOR WEDNESDAY
AND THURSDAY. LAKE SNOW SHOWERS ARE POSSIBLE FROM WEDNESDAY INTO
WEDNESDAY NIGHT. WEDNESDAY NIGHT WE SHOULD SEE SOME LIGHT ACCUMS
TOWARDS THE COAST WITH A DGZ THAT IS JUST OFF THE GROUND AND SOME
DECENT MOISTURE BELOW 850MB/S.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 329 PM EST MON MAR 2 2015

UNSEASONABLY COLD WEATHER WILL CONTINUE THURSDAY WHEN MAX TEMPS WILL
ONCE AGAIN ONLY REACH THE TEENS. SCATTERED LAKE EFFECT SNOW SHOWERS
WILL LINGER WITH H8 TEMPS STILL DOWN AROUND -20 TO -22 C. SOME LIGHT
SNOW ACCUMULATIONS ARE POSSIBLE MAINLY WEST OF US-131.

TEMPS WILL UNDERGO A GRADUAL MODERATING TREND FRIDAY THROUGH
SATURDAY AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL. BEYOND THAT
SOME OF OUR LATEST MEDIUM RANGE GUIDANCE INCLUDING THE 12Z GFS
CONTINUES THAT ANOTHER CLIPPER SYSTEM WILL BRING COLDER AIR AND A
CHANCE OF SNOW SHOWERS SATURDAY NIGHT AND SUNDAY.

ANOTHER CLIPPER SYSTEM WILL POTENTIALLY MOVE IN FROM THE NW EARLY
NEXT WEEK BRINGING ANOTHER CHANCE FOR SNOW SHOWERS AND COLDER TEMPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1201 AM EST TUE MAR 3 2015

VFR CONDITIONS OVERNIGHT WILL SUDDENLY DROP TO IFR AROUND 14Z AS
SNOW MOVES IN. THE SNOW WILL MIX WITH FREEZING RAIN ACROSS
SOUTHERN LOWER MICHIGAN BY 15Z. CONDITIONS ARE EXPECTED TO REMAIN
IFR THROUGH THE AFTERNOON WITH SOME LIFR AS WELL. WINDS WILL BE SOUTH
TONIGHT LESS THAN 10 KNOTS AND INCREASE TO 15 KNOTS FROM THE
SOUTHEAST DURING THE MORNING...THEN SOUTHWEST IN THE AFTERNOON
WITH GUSTS TO 20 KNOTS.

&&

.HYDROLOGY...
ISSUED AT 1205 AM EST MON MAR 2 2015

AREA STREAMS AND RIVERS REMAIN STABLE WITH NO NOTABLE VARIATIONS
TO RAISE CONCERNS. THE OVERALL THINKING WITH THE FORECAST IS
CONSISTENT WITH PRIOR STATEMENTS IN THE LAST 48 HOURS.

SEE-SAW TEMPERATURES ARE EXPECTED OVER THE NEXT SEVERAL DAYS WITH
30S TUESDAY...RETURNING TO THE TEENS AND 20S WEDNESDAY THROUGH
FRIDAY. THE STORM SYSTEM TUESDAY BRINGS THE BULK OF THE MOISTURE
BEFORE CONDITIONS BECOME RELATIVELY TAME FOR THE REMAINDER OF THE
WEEK. QPF IS EXPECTED TO BE AROUND ONE-HALF AN INCH OR LESS AS THE
STORM EXITS LATE TUESDAY. MILDER TEMPERATURES ARE SHORT-LIVED AND
ARE ONLY BEING CONSIDERED MILD IN RELATIVE TERMS. SNOW ALREADY ON
THE GROUND SHOULD SOAK UP MUCH OF WHAT FALLS AS RAIN OR FREEZING
RAIN. ANY RIVER RESPONSE SHOULD HOLD OFF UNTIL WE GET A MORE
SUSTAINED AND ROBUST WARM PERIOD. FOR THAT...IT MAY NOT BE UNTIL
NEXT WEEK. THAT WILL BE SOMETHING TO CONSIDER IN DETAIL AS THE
WEEK PROGRESSES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 AM TO 8 PM EST TUESDAY FOR
     MIZ037>040-043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

AVIATION...OSTUNO





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