Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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336
FXUS63 KGRR 120825
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
325 AM EST FRI FEB 12 2016

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE

.SYNOPSIS...
ISSUED AT 325 AM EST FRI FEB 12 2016

AN ARCTIC COLD FRONT IS MOVING ACROSS THE UP AND WILL MOVE DOWN THE
LOWER PENINSULA THIS MORNING. A BAND OF SHOW WILL DEVELOP ALONG THIS
FRONT AS IT MOVES THROUGH. AFTER THAT LAKE EFFECT SNOW SHOWERS WILL
DEVELOP LATER TODAY AND CONTINUE TONIGHT. HEAVY SNOW IS POSSIBLE
ALONG THE LAKE SHORE SOUTH OF HOLLAND.

VERY COLD AIR RESULTING IN HIGHS IN THE TEENS WILL CONTINUE THROUGH
THE WEEKEND BEFORE WARMER AIR IN THE 30S ARRIVES MONDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 325 AM EST FRI FEB 12 2016

THE GOING FORECAST IS STILL MAINLY ON TRACK AND THE HEADLINES ARE
UNCHANGED. THE MAIN CHANGE TO THE FORECAST WAS TO BACK OFF ON ACCUMS
INLAND TODAY AND TONIGHT.

CURRENT SFC CHART SHOWS THE ARCTIC FRONT STRETCHING WEST ACROSS THE
UP. THIS FRONT WILL PASS THROUGH THE CWA BY LATE MORNING. LATEST
HRRR SHOWS A BAND OF SNOW DEVELOPING AHEAD OF THE FRONT ALONG I-96
BY 9 AM OR SO AND THEN MOVING SOUTH. THERE MAY BE A LULL IN THE PCPN
FROM MID TO LATE MORNING BEFORE LAKE EFFECT SNOWS DEVELOP. H8 TEMPS
FALL FROM -18C AROUND 18Z TO -26C BY 06Z TONIGHT. INSTABILITY OVER
THE LAKE WILL BE EXTREME BUT MOISTURE MAY BE LIMITED A BIT. WITH
THAT IN MIND WE BACKED OFF ACCUMS A BIT ESPECIALLY EAST OF US-131.
STILL THINK THE HEAVIEST SNOW WILL FALL SOUTH OF HOLLAND ALONG THE
LAKE SHORE.

WINDS WILL INCREASE THIS AFTERNOON AND CONTINUE THROUGH THE EVENING.
AS TEMPS FALL INTO THE SINGLE DIGITS...WIND CHILLS WILL FALL BELOW 0
TONIGHT AND CONTINUE BELOW 0 MUCH OF SATURDAY. HIGHS SATURDAY WILL
ONLY CLIMB TO THE MID TEENS. WE SHOULD SEE TEMPS BELOW 0 IN MANY
LOCATIONS SATURDAY NIGHT INLAND AS SKIES WILL CLEAR.

THE NEXT CLIPPER WILL SPREAD SNOW TOWARD THE CWA SUNDAY AFTERNOON
BUT MUCH OF IT WILL HOLD OFF UNTIL SUNDAY NIGHT.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM EST FRI FEB 12 2016

LONG TERM PERIOD STILL LOOKS FAIRLY UNEVENTFUL BY FEBRUARY
STANDARDS. THE FLOW IS ZONAL IN NATURE WITH NO MAJOR SYSTEMS
EXPECTED TO AFFECT SOUTHWEST LOWER MI. THERE IS A SURGE OF COLDER
AIR MID WEEK...ALTHOUGH IS IT NOT TERRIBLY COLD (850MB TEMPS MINUS
MID TEENS C). OTHERWISE TEMPS WILL BE FAIRLY CLOSE TO SEASONAL
NORMALS.

AS FOR THE DETAILS...THE MODELS ARE FAIRLY LOCKED IN ON AN UPPER
SHORTWAVE DIVING THROUGH THE AREA SUNDAY NIGHT AND MONDAY.
THERE IS A WEAK SURFACE REFLECTION DURING THIS TIME FRAME...MORE OF
A WEAK TROUGH. HAVE CHANCES FOR LIGHT SNOW IN THE FORECAST...30-50
PCT. COULD SEE SOME LIGHT ACCUMS...INCH OR LESS BUT NOT MUCH MORE
THAN THAT.

BEYOND THAT...AS HAS BEEN DISCUSSED IN PRIOR AFD/S...THERE ARE
MULTIPLE SHORTWAVES TRYING TO PHASE IN THE EASTERN THIRD OF THE
COUNTRY TUESDAY/WEDNESDAY. THE PHASING SEEMS TO BE TRENDING TOWARD
OCCURRING EAST OF THE GREAT LAKES WITH A STRONG LOW FORMING IN NEW
ENGLAND. THE AFFECTS ON OUR AREA SHOULD BE LIMITED. HAVE SOME SMALL
CHANCES FOR LIGHT SNOW IN THE FORECAST TUESDAY-THURSDAY ON THE ORDER
OF 20-30 PCT. THE COLD AIR THAT IS TUGGED INTO THE REGION FROM THE
NORTH MID WEEK IS DUE TO THE WRAPPED UP LOW ON THE EAST COAST. IT
APPEARS THERE IS A WINDOW FOR LAKE EFFECT WEDNESDAY AND WEDNESDAY
NIGHT. DRY AIR SHOULD KEEP THE LAKE EFFECT IN CHECK THOUGH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1152 PM EST THU FEB 11 2016

VFR WEATHER IS EXPECTED OVERNIGHT WITH PREDOMINANTLY MVFR AFTER
12Z FRIDAY. SNOW SHOWERS WILL FLARE UP ONCE AGAIN FRIDAY MORNING
AS AN ARCTIC FRONT DROPS SOUTH THROUGH LOWER MICHIGAN. SPOTTY IFR
IS NOT OUT OF THE QUESTION IN HEAVIER SNOW. THE EASTERN TAF
SITES...LAN...JXN...AND BTL SHOULD BE ABLE TO IMPROVE TO VFR
FRIDAY EVENING AS THE SNOW TRANSITIONS TO A NORTH NORTHWEST FLOW
LAKE EFFECT SCENARIO. MVFR WILL LINGER AT MKG.

WESTERLY WINDS WILL INCREASE TO 10-15 KTS THROUGH LATE MORNING
INTO THE AFTERNOON. GUSTS TO 25 KTS WILL BE POSSIBLE DURING THE
AFTERNOON AND EVENING AS WINDS GO NORTHWEST.


&&

.MARINE...
ISSUED AT 325 AM EST FRI FEB 12 2016

WINDS WILL INCREASE TODAY AS THE ARCTIC FRONT MOVES SOUTH ACROSS THE
LAKE. UPGRADED THE GALE WATCH TO A WARNING. GALES TO 40 KNOTS
EXPECTED THIS AFTERNOON AND TONIGHT. WINDS WILL DIMINISH AFTER
MIDNIGHT. THE COMBINATION OF THE STRONG WINDS AND VERY COLD AIR WILL
ALSO RESULT IN HEAVY FREEZING SPRAY THIS AFTERNOON AND TONIGHT.

&&

.HYDROLOGY...
ISSUED AT 1216 PM EST THU FEB 11 2016

NOT MUCH HAS CHANGED IN THE LAST 24 HOURS. THE DOWNWARD TREND
CONTINUES AT MAPLE RAPIDS...WHICH HAS ALLOWED US TO DROP THE
ADVISORY AT THAT LOCATION.

THIS MORNINGS OBSERVATIONS ON THE GRAND RIVER AT ROBINSON TWP SHOW
SMALL...THIN PIECES OF ICE FLOWING IN THE RIVER. A FEW RIVER
GAUGES THROUGHOUT SOUTHWEST LOWER MICHIGAN ARE BEGINNING TO SHOW
SIGNS OF BEING AFFECTED BY ICE. AT THIS POINT IT IS NOT AN ISSUE.
HOWEVER...TEMPERATURES WILL ONLY CONTINUE TO GET COLDER THROUGH
THE WEEKEND. THIS WILL SUPPORT ADDITIONAL ICE FORMATION THROUGH AT
LEAST SUNDAY MORNING WITH OVERNIGHT TEMPERATURES IN THE SINGLE
DIGITS. SOMETHING TO CONSIDER IS THAT WE ARE LATE IN THE WINTER
SEASON AND WATER TEMPERATURES ARE LOW ENOUGH THAT ICE DEVELOPMENT
COULD OCCUR FAIRLY QUICKLY WITH LONG PERIODS OF SUB-FREEZING AIR.

OVERALL PRECIPITATION AMOUNTS ARE STILL LOW THROUGH THE NEXT 7
DAYS. ASIDE FROM ANY LOCAL HEAVY LAKE EFFECT SNOWFALL THAT
OCCURS...OVERALL AMOUNTS WILL BE FAIRLY LIGHT. EVEN THIS WILL NOT
BE REALIZED UNTIL MELTING TAKES PLACE. THE MAIN CONCERN WILL BE
RIVER FLUCTUATION DUE TO ICE IN THE EVENT THAT THICK ICE DEVELOPS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 PM EST SATURDAY
     FOR MIZ064-071.

     WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
     EVENING FOR MIZ044-057-065.

     WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 4 PM EST
     SATURDAY FOR MIZ037-038-043-050-056-072.

LM...HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
     SATURDAY FOR LMZ844>849.

     SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
     LMZ844>849.

     GALE WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST SATURDAY FOR
     LMZ844>849.

&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...DUKE
AVIATION...EBW
HYDROLOGY...JAM
MARINE...04



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