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000
FXUS63 KAPX 160604
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
104 AM EST MON DEC 16 2013

.SYNOPSIS...
ISSUED AT 423 PM EST SUN DEC 15 2013

N AXIS OF LOW PRESSURE WILL SLIP DOWN THROUGH THE REGION THIS
EVENING...MAINTAINING HEAVIER LAKE EFFECT SNOWS FOR A GOOD PORTION
OF NORTHERN MICHIGAN. HOWEVER...SNOW SHOWERS WILL DIMINISH OVERNIGHT
AS DRIER AIR OVERSPREADS THE REGION. ADDITIONAL SNOW WILL FALL LATER
MONDAY AND MONDAY NIGHT AS A WARM FRONT MAKES ITS WAY INTO THE GREAT
LAKES. COLD TEMPERATURES WILL LAST THROUGH MONDAY...BUT SOMEWHAT
MILDER CONDITIONS WILL ARRIVE TUESDAY.

&&

.UPDATE...
ISSUED AT 102 AM EST MON DEC 16 2013

NORTH FLOW LAKE EFFECT SNOW SHOWERS CONTINUE...ALBEIT AT A MUCH
LESSER INTENSITY. NO DOUBT SOME LIGHT ACCUMULATIONS CONTINUE. WILL
LET INHERITED HEADLINES RIDE FOR NOW AND REEVALUATE AT MAIN FORECAST
PACKAGE.

UPDATE ISSUED AT 1100 PM EST SUN DEC 15 2013

LATEST MESO-LOW IS NOW MOVING THRU NRN LWR MICHIGAN LATE THIS
EVENING...PRODUCING ANOTHER (QUICK) BURST OF HEAVY SNOW FOR
PORTIONS OF FAR NW/N CENTRAL LWR MICHIGAN OVER THE PAST FEW HOURS.
ANOTHER 1 TO 3 INCHES OF SNOW HAS FALLEN ACROSS THAT AREA AS A
RESULT...BUT BANDS OF SNOW HAVE BEEN QUITE TRANSIENT...AND ARE NOW
ON THEIR WAY OUT OF LOCATIONS EAST OF US-131. WINDS HAVE ABRUPTLY
SHIFTED TO THE NORTH ACROSS FAR NW LWR MICHIGAN BEHIND THIS MESO-
LOW...SHIFTING FOCUS OF HEAVIEST AND MOST PERSISTENT SNOW BANDS TO
LOCATIONS WEST OF US-131. HAVE DROPPED ALL HEADLINES EAST OF
US-131...AND HAVE EXTENDED HEADLINES WEST OF US-131 THRU 12Z AS
NORTHERLY LOW LEVEL FLOW CONTINUES TO AIM RESIDUAL LAKE EFFECT
SNOW BANDS INTO THIS AREA. EXPECT ANOTHER 1 TO 3 INCHES OF
ADDITIONAL SNOW FOR THESE AREAS OVERNIGHT.

UPDATE ISSUED AT 700 PM EST SUN DEC 15 2013

AFTERNOON MESO-LOW HAS EXITED OUR CWA...ONLY TO BE REPLACED BY
ANOTHER MESO-LOW THAT DROPPED SOUTH OUT OF LAKE SUPERIOR AND INTO
FAR NRN LAKE MICHIGAN OVER THE PAST FEW HOURS. THIS LOW IS IN THE
VCNTY OF LITTLE TRAVERSE BAY ATTM...AND WILL LIKELY CONTINUE
SOUTHWARD THRU THE REST OF NW LWR MICHIGAN OVER THE NEXT FEW
HOURS. THIS LOW WILL REINFORCE SHARP LOW LEVEL CONVERGENCE THAT
BROUGHT SOME LOCATIONS OF NW LWR MICHIGAN HEAVY SNOW THIS
AFTERNOON AND EARLY EVENING (WE HAVE RECEIVED AROUND 10 INCHES OF
NEW SNOW AT THE OFFICE DURING THE AFTERNOON AND EARLY EVENING!).
STILL NOT OUT OF THE WOODS JUST YET AS PORTIONS OF NW LWR MICHIGAN
WILL SEE ANOTHER QUICK BOUT OF HEAVY SNOW OVER THE NEXT COUPLE OF
HOURS AS THIS FEATURES MOVES THRU. WILL CERTAINLY KEEP ALL
HEADLINES IN TACT...AND WILL CLOSELY WATCH THE TIMING OF THE MESO-
LOW AND SNOWFALL COVERAGE AND INTENSITY AS THIS FEATURE MOVES
THRU. WILL LIKELY NEED TO MAKE ADDITIONAL SNOWFALL ADJUSTMENTS
BASED ON SHORT TERM RADAR TRENDS THROUGHOUT THE NIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 423 PM EST SUN DEC 15 2013

MAIN FOCUS FOR THE SHORT TERM WILL BE THE FINER MESOSCALE DETAILS
ASSOCIATED WITH ONGOING LAKE EFFECT EVENT OVER NORTHERN LOWER.
SURFACE ANALYSIS CONTINUES TO SHOW BROAD INVERTED TROUGHING OVER
NORTHERN MICHIGAN...WITH THE TROUGH AXIS CENTERED OVER NORTHEAST
LOWER EXTENDING NORTHWESTWARD BACK INTO THE EASTERN U.P. THE FIRST
OF TWO LAKE ENHANCED VORTICES IS NOW PIN WHEELING ITS WAY ACROSS
NORTHEAST LOWER AT THIS TIME...WHICH HAS IMPACTED THE BL WIND
FIELDS...AND HAS LED TO TWO DISTINCT AREAS OF CONVERGENT LAKE EFFECT
BANDING. THE FIRST REGION HAS BEEN CENTERED OVER
CHARLEVOIX...ANTRIM...OTSEGO AND LEELANAU COUNTIES. THE COMBINATION
OF VERY FAVORABLE DELTA T`S...EXCELLENT INVERSION HEIGHTS /WITH THE
BULK OF THE CLOUD BEARING LAYER CENTERED IN THE DENDRITIC GROWTH
ZONE/...AND SUFFICIENT MID LEVEL MOISTURE ASSOCIATED PASSING LARGER
SCALE SHORT WAVE HAS LED TO LOCALLY INTENSE LAKE EFFECT SNOW BANDS.
VISIBILITIES HAVE BEEN DOWN TO JUST SEVERAL HUNDRED FEET IN THE MOST
INTENSE BANDS. INHERITED ADVISORIES WERE UPGRADED TO WARNINGS
RUNNING THROUGH THIS EVENING...AS THE COMBINATION OF RADAR ESTIMATES
AND SNOWFALL REPORTS SUGGEST AMOUNTS IN EXCESS OF 8 INCHES OVER THIS
AREA.

MEANWHILE...FIRST MESO-VORTEX HAS ALSO BEEN RESPONSIBLE FOR
CONVERGENT FLOW ALONG THE LAKE HURON COAST LINE OVER NORTHEAST
LOWER...SPECIFICALLY AROUND THE M-23 CORRIDOR. A BAND OF LOCALLY
HEAVY LES HAS SET UP FROM JUST EAST OF ALPENA UP TO AROUND
CHEBOYGAN...WITH AREAS THERE PICKING UP AN ESTIMATED 3 TO 6 INCHES
OF SNOWFALL SINCE THIS MORNING. THIS BAND IS GRADUALLY GETTING
KICKED OUT OF THE REGION LATE THIS AFTERNOON WITH THE PASSAGE OF THE
FIRST VORTEX...WITH CONVERGENT WIND FIELDS EXPECTED TO MORPH INTO A
MORE UNIFORM NORTH TO NORTHWEST FLOW.

FOR TONIGHT...INTENSE LAKE EFFECT SNOW BANDS OVER NORTHWEST LOWER
WILL BEGIN TO IMPACT THE GRAND TRAVERSE BAY REGION...AS THE SECOND
LAKE ENHANCED MESOLOW DROPS DOWN FROM EASTERN LAKE SUPERIOR INTO
NORTHERN LAKE MICHIGAN THIS EVENING. THIS WILL FORCE THE 1000-850MB
WINDS TO BECOME MORE NORTHERLY...FOCUSING THE LES ALONG AND WEST OF
THE US-131 CORRIDOR THIS EVENING. INVERSION HEIGHTS...THE STRENGTH
OF THE BL FLOW AND OMEGA IN THE DGZ STILL REMAIN VERY FAVORABLE FOR
RAPID FLUFFY ACCUMULATIONS THIS EVENING...AND HAVE HOISTED LES
ADVISORIES FOR COUNTIES SOUTH OF THE GTV BAY REGION ALONG AND WEST
OF US-131...AS WELL AS FOR KALKASKA AND CRAWFORD COUNTIES UNTIL LATE
THIS EVENING. IT WON`T TAKE MUCH TO REACH ADVISORY LEVEL SNOWFALL AS
THE BANDS MORPH FROM BEING NW/SE ORIENTED TO A MORE NNW/SSE ORIENTED
REGIME /SNOWFALL REPORTS WITH THE STRONGEST BANDS HAVE EXCEEDED ONE
INCH PER HOUR/.

THE OTHER STORY FOR TONIGHT WILL BE A POTENTIALLY CHILLY NIGHT FOR
EASTERN UPPER...EXTENDING POSSIBLY INTO NORTH CENTRAL LOWER AS THE
MODEL CONSENSUS DEPICTS A NORTH TO NNE DRAINAGE FLOW OFF THE ONTARIO
PLATEAU. SHOULD SUFFICIENT CLEARING BE REALIZED DUE TO SUBSIDENCE
WITH THE DEPARTING SHORT WAVE TROUGH...EASTERN UPPER SHOULD FALL
WELL BELOW ZERO...WITH NEAR ZERO READINGS FOR INTERIOR PORTIONS OF
NORTHERN LOWER. MAIN UNCERTAINTY WILL BE THE IMPACT OF LAKE EFFECT
CLOUD COVER...AS MESOLOWS COULD THROW A WRENCH IN THINGS AND KEEP
CLOUDS AROUND FOR MOST OF THE AREA TONIGHT. OPTED FOR A CLEARER
APPROACH TO SKY COVER FOR NOW...BUT TRENDS WILL CERTAINLY HAVE TO BE
MONITORED.

SUNDAY...WIND FIELDS WILL RELAX AND BECOME SOUTHWESTERLY LATE
TONIGHT INTO MONDAY...AS UPPER LEVEL INVERTED TROUGH PUSHES OFF TO
THE EAST AND THE NEXT SHORTWAVE COMES DOWN THE WINTER EXPRESS RAIL
ROAD TRACK. DELTA T`S AND INVERSION HEIGHTS STILL LOOK VERY
FAVORABLE FOR THIS NEXT SOUTHWEST FLOW LAKE ENHANCED EVENT...WHICH
SHOULD RAMP UP LATE MONDAY MORNING AND CONTINUE THROUGH MONDAY
AFTERNOON AS SYNOPTIC FORCING AND MID LEVEL MOISTURE INCREASE WITH
THE APPROACHING WAVE. GIVEN RECENT LES TRENDS AROUND HERE
LATELY...WOULD NOT BE SURPRISED IF SOME TYPE OF HEADLINE WAS NEEDED
FOR MACKINAC COUNTY FOR AT LEAST ADVISORY LEVEL SNOWS OVER THE US-2
CORRIDOR. LIKED THE INHERITED SNOW AMOUNTS OF 3 TO 4 INCHES UP THERE
FOR NOW AS A MORE WIDESPREAD TOTAL...WITH LOCALLY HIGHER AMOUNTS
CERTAINLY POSSIBLE. GENERAL LIGHT SNOW IS EXPECTED FOR OTHER AREAS
AWAY FROM THE US-2 CORRIDOR AND OVER NW LOWER NEAR LM...AWAY FROM
THE INFLUENCE OF LAKE ENHANCEMENT. HIGHS MONDAY LOOK TO REMAIN
COLD...STUCK IN THE TEENS TO AROUND 20.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 423 PM EST SUN DEC 15 2013

(12/16)MONDAY NIGHT...A WEAK WARM FRONT MOVES INTO THE FORECAST AREA
DURING THE EVENING. THIS SHIFTS THE WINDS FROM SW TO WSW BY 06Z AND
WITH THE 850 MB TEMPERATURES AROUND -13 TO -12C THROUGH THE EVENING
AND THE MOISTURE IN THE 850-700 MB LAYER OF BETTER THAN 80% WE WILL
SEE GOOD LAKE ENHANCEMENT WITH THE SFC TROUGH AS IT GOES THROUGH. SO
UPPED THE AMOUNTS BASED ON THE WIND DIRECTION FOR THE LES OVER TOP
OF WHAT HPC HAD FOR THE SYNOPTIC SYSTEM. THE NAM TRIES TO DRY THINGS
OUT IN THE SW COUNTIES AFTER 06Z, BY THE GFS AND ECMWF CONTINUE THE
MOISTURE. SO HAVE MINOR TO LIGHT SNOW AMOUNTS IN THE SECOND HALF OF
THE NIGHT AFTER THE FRONTAL PASSAGE. THIS WILL HAVE TO BE REFINED,
BUT FIGURE THAT WE WILL NUDGE THINGS IN THAT DIRECTION. SO THE EARLY
GUESSES FOR THE WHOLE NIGHT IS THAT WE WILL GET MODERATE AMOUNTS
AROUND THE STRAITS, AND LIGHT AMOUNTS OUT SIDE OF THAT AREA.

(12/17)TUESDAY...THE SFC LOW DROPS INTO UPPER GREAT LAKES WHICH WILL
BRING MORE SNOW TO THE REGION. HOWEVER, THE MODELS HAVE NW WINDS
WITH 850 MB TEMPERATURES AROUND -12C ALL DAY. MOISTURE REMAINS
AROUND 80% AS WELL, SO AGAIN TRIED TO INCREASE THE AMOUNTS MODESTLY
FROM THE HPC IDEA OF THE SYNOPTIC QPF. FOR THE WHOLE DAY, THINK THAT
WE GET LIGHT TO MODERATE SNOW AMOUNTS IN MOST OF THE NW FLOW ZONES
FOR E UPPER AND NW LOWER. THE REST OF THE FORECAST WILL SEE MINOR TO
LIGHT SNOW AMOUNTS.

TUESDAY NIGHT...AGAIN THE NAM TRIES TO DRY THINGS OUT EARLIER THAN
ANY OF THE OTHER MODELS. SO AM GOING WITH THE NW FLOW THAT THE GFS
AND ECMWF HAVE WITH 80% RH IN THE 850-700 MB LAYER AND 850 MB
TEMPERATURES AROUND -15C. WE MAY SEE SOME DECENT SNOW IN THE
EVENING. OVERNIGHT, THE SNOW WILL START TO DIMINISH AS THE SYNOPTIC
MOISTURE BEGINS TO DRY OUT SOME, HOWEVER, IT WILL PROBABLY BE AT THE
LEAST MODERATE AMOUNTS IN THE NW FLOW REGIONS.

(12/18)WEDNESDAY...WE GET INTO A DISAGREEMENT BETWEEN THE MODELS AS
THE NEXT SYSTEM GETS READY TO START THE NEXT ROUND OF SNOW IN THE
UPPER GREAT LAKES. IT LOOKS LIKE THE WARM FRONT BEGINS TO FORM UP
ACROSS WISCONSIN AND S LOWER. THE GFS SPUN UP A SECONDARY SFC LOW IN
THE BOUNDARY WATERS, THAT KEEPS WARM FRONT FROM PRODUCING ANY
PRECIPITATION, AS WELL AS WARMS THE FORECAST AREA UP A BIT. HOWEVER,
WE ALSO GET INTO THE WARM SECTOR, OVERNIGHT, THE WE DRY OUT AND MOST
OF THE PRECIPITATION WILL BE MAINLY IN CANADA. THE ECMWF HAS NO
SECONDARY LOW, AND KEEP THE WARM FRONT SOUTH OF US, WITH MOISTURE IN
THE UPPER GREAT LAKES. SO THIS ALLOWS FOR SOME SNOW DURING THE DAY
AND OVERNIGHT.

EXTENDED (THURSDAY THROUGH SUNDAY)...

(12/19)THURSDAY...THE ECMWF KEEPS US IN THE COLD AIR AND STILL HAS
THE MOISTURE ASSOCIATE WITH THE FRONT. IT LOOKS LIKE THAT THE
PRECIPITATION WILL BE IN THE FROM OF SNOW THROUGH THE AFTERNOON AND
INTO THE NIGHT. THE GFS IS DRY IN THE MORNING AND BLAST THE COLD AIR
INTO THE REGION THEN SNOWS BY THE AFTERNOON. SO WILL JUST GO WITH
THE CHANCE OF SNOW.

(12/20)FRIDAY...WILL LEAVE THE SNOW IN THE FORECAST AREA FOR NOW.
HOWEVER, THE ECMWF IS BLASTING A SFC RIDGE INTO THE FORECAST AREA BY
THE AFTERNOON DRYING EVERYTHING OUT. THE GFS LEAVES ENOUGH MOISTURE
AND NW FLOW FOR LAKE EFFECT. HOWEVER, BY THE EVENING, THE HIGH MOVES
THROUGH THE FORECAST AREA. SO CHANCE OF SNOW DURING THE DAY, AND DRY
AT NIGHT.

(12/21)SATURDAY...ANOTHER SLUG OF MOISTURE MOVES INTO THE FORECAST
AREA, SO THAT IT SNOWS OVER THE REGION. THE QUESTION IS DOES THE SFC
LOW DROP INTO N LOWER LATE IN THE DAY AND AT NIGHT, OR DOES IT RIDE
UP THE OHIO VALLEY. TWO SOLUTIONS, ONE ANSWER, SNOW.

(12/22)SUNDAY...WHILE THE GFS DRIES US OUT, THAT MAY BE ON THE FAST
SIDE AS BOTH THE ECMWF AND THE GFS HAVE CYCLONIC FLOW WITH THE STORM
LEAVING THE REGION. IT SEEMS THAT THE MOISTURE SHOULD FLOW ON THE
BACKSIDE OF THE LOW AND STILL BE IN THE FORECAST AREA, SO WILL HAVE
CHANCE POPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM EST SUN DEC 15 2013

HEAVIEST SNOWFALL AND IFR CONDITIONS WILL PERSIST OVERNIGHT FOR AREAS
WEST OF US-131 OVERNIGHT THANKS TO LOW LEVEL NORTHERLY FLOW BEHIND
THE DEPARTING MESO-LOW...IMPACTING MAINLY TVC AND MBL. LOW LEVEL
WINDS WILL QUICKLY SHIFT TO THE S/SW ON MONDAY AS A WARM FRONT
LIFTS THRU THE REGION...BRINGING MORE WIDESPREAD SYNOPTIC SNOWFALL
AND MVFR/IFR CONDITIONS TO THE REGION FOR MONDAY INTO MONDAY NIGHT.


&&

.MARINE...
ISSUED AT 423 PM EST SUN DEC 15 2013

SCA WILL CONTINUE FOR THE NEARSHORE MARINE ZONES OVER NW LOWER
THROUGH THIS EVENING WITH GUSTY NORTH TO NNW WINDS AND WAVE
HEIGHTS OF 5 TO 8 FEET...ESPECIALLY FROM GRAND TRAVERSE LIGHT
SOUTH. WINDS AND WAVES WILL SUBSIDE BELOW SCA CRITERIA SHORTLY
AFTER MIDNIGHT TONIGHT...AS THE PRESSURE GRADIENT RELAXES WITH A
DEPARTING SURFACE TROUGH. SCA WILL BE NEEDED BY MONDAY AFTERNOON
ONCE AGAIN AS SOUTHWESTERLY WINDS INCREASE AHEAD OF THE NEXT
CLIPPER SYSTEM...WITH SCA CONDITIONS CONTINUING INTO MONDAY NIGHT.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ020.
     LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ025-
     026-031-032.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ323-
     344>346.
LS...NONE.

&&

$$

UPDATE...MB
SYNOPSIS...BA
SHORT TERM...NS
LONG TERM...JL
AVIATION...MR
MARINE...NS