Area Forecast Discussion
Issued by NWS Marquette, MI

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624
FXUS63 KMQT 091316
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
816 AM EST TUE FEB 9 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EST TUE FEB 9 2016

WV IMAGERY AND RAP ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A
PROMINENT MID/UPPER LEVEL RIGE OVER THE WRN CONUS AND A TROUGH FROM
HUDSON BAY THROUGH THE GREAT LAKES INTO THE SE CONUS. AT THE
SFC...STRONG NRLY FLOW PREVAILED THROUGH THE WRN LAKES BTWN A RIDGE
OVER THE PLAINS AND A LOW NEAR THE SRN END OF LAKE HURON. PLENTY OF
INSTABILITY OVER LAKE SUPERIOR WITH 850 MB TEMPS TO AROUND -22C AND
THE PRESENCE OF ABUNDANTY 850-500 MB MOISTURE SUPPORTED MODERATE TO
HEAVY LES INTO THE WRN CWA NEAR IWD WHERE THE LOW LEVEL CONV WAS
STRONGEST. LES ALSO CONTINUED OVER THE REST OF NRN UPPER MI BUT WAS
NOT AS HEAVY.

TODAY...THE MODELS WERE IN RELATIVELY GOOD AGREEMENT THAT THE
DEEPER MOISTURE WILL SLIDE TO THE EAST OF WRN LAKE SUPERIOR WITH
INVERSION HEIGHTS DROPPING TO AROUND 4K FT. SO...WITH DIMINISHING
SNOWFALL RATES EXPECTED...THE LES WARNING/ADVISORIES EXPIRATION OF
21Z LOOKS ON TRACK AFTER ADDITIONAL ACCUMULATONS OF 3 TO 6 INCHES.
HOWEVER...LIGHTER LES WILL CONTINUE INTO TONIGHT. EVEN WITH LESS
FAVORABLE LOW LEVEL CONV INTO N CNTRL UPPER MI...EXPECT LES WILL
INCREASE TODAY WITH SNOWFALL AMOUNTS MAINLY IN THE 2 TO 4 INCH RANGE.
IN ADDITION...THE GUSTY N WINDS ALONG THE LAKE WILL PRODUCE
CONSIDERABLE BLSN. AN ADVY WAS ISSUED FOR MARQUETTE/ALGER COUNTIES
WHICH WILL EXTEND INTO WED. TEMPS WILL REMAIN BLO NORMAL WITH HIGHS
FROM 10 TO 15 OVER THE WEST HALF TO THE LOW 20S AND EAST.

TONIGHT...A WEAK SHRTWV MOVING INTO THE NRN LAKES FROM NW ONTARIO
ALONG WITH SLIGHTLY COLDER AIR WILL HELP BOOST SNOWFALL
RATES...MAINLY OVER THE CNTRL AREAS DOWNSTREAM FROM THE LONGER
FETCHAND WHERE UPSTREAM LOW LEVEL DRYING WILL HAVE LESS INFLUENCE.
LAND BREEZES AND SLIGHTLY VEERING WINDS MAY HELP INCREASE LOW LEVEL
CONV INTO EASTERN MARQUETTE AND WRN ALGER COUNTIES WHERE ADDITIONAL
SNOWFALL AMOUNTS OF 3 TO 5 INCHES ARE POSSIBLE. WITH THE DGZ
LOWERING CLOSER TO THE SFC AND GREATER DRYING...EXPECT MAINLY 1 TO 4
INCH AMOUNTS OVER THE WEST. EVEN WITH THE VERY COLD AIRMASS OVER THE
AREA...THE LAKE INFLUENCE WILL KEEP TEMPS IN THE 0 TO 5F RANGE WEST
AND 5 TO 10 EAST.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 500 AM EST TUE FEB 9 2016

THE MAIN ISSUES FOR THE EXTENDED FORECAST PERIOD CONSISTS OF SEVERAL
PERIODS OF LIGHT TO MODERATE LAKE EFFECT SNOW THROUGH THE END OF THE
WORK WEEK ALONG WITH A TREND TOWARD MUCH COLDER THAN NORMAL
TEMPERATURES BY FRIDAY AND SATURDAY.

WEDNESDAY THROUGH THURSDAY...THE BROAD 500MB TROUGH WILL REMAIN IN
PLACE OVER THE EASTERN CONUS WITH CONTINUED RIDGING OVER THE WEST.
THE SHORTWAVE THAT SLID THROUGH TUESDAY NIGHT WILL CONTINUE TO BE
OVER THE CENTRAL AND EASTERN U.P. WEDNESDAY MORNING BEFORE SLIDING
EAST OF THE AREA BY WEDNESDAY EVENING. AT THE SURFACE...THE LOW
PRESSURE SYSTEM OVER LAKE HURON WILL BEGIN TO SLIDE TO THE
NORTHEASTERN U.S BY WEDNESDAY EVENING AND OFF THE COAST THURSDAY.
THIS WILL KEEP MOST OF THE U.P. IN THE CONTINUED NORTH TO NORTH-
NORTHWESTERLY FLOW. THE DEEPER MOISTURE WILL SLOWLY BEGIN TO EXIT TO
THE EAST OF THE AREA THROUGH THE DAY WEDNESDAY...EVEN THOUGH MOST OF
THE U.P. WILL STILL SEE LAKE EFFECT SNOW AND CONTINUED CLOUD COVER.
THE MORE FOCUSED SNOW WILL BE OVER THE EASTERN U.P. AS THE DEEPER
MOISTURE WILL LINGER THERE THE LONGEST AND THAT AREA WILL BE IN
CLOSER PROXIMITY TO THE SHORTWAVE AXIS INTO WEDNESDAY EVENING. THE
CHILLY AIR AT 850MB IN THE -20C TO -23C RANGE WILL STILL BE IN PLACE
KEEPING SLR VALUES LOWER THAN WHAT THEY WOULD BE IF THE MOISTURE AND
CONVECTIVE LAYER WERE DEEPER IN THE PREFERRED DGZ. INVERSION HEIGHTS
WILL BE AROUND 6-8KFT OVER THE CENTRAL AND EAST THROUGH WEDNESDAY
EVENING...HOWEVER...THE BETTER MOISTURE IS ONLY PROGGED TO BE IN
PLACE THROUGH ABOUT 5-6KFT. LATE WEDNESDAY NIGHT INTO
THURSDAY...MUCH DRIER AIR IS PROGGED TO SLIDE INTO THE AREA AS THE
UPPER LEVEL TROUGH AXIS SLIDES EVER SO SLOWLY TO THE EAST AND A
RIDGE OF HIGH PRESSURE APPROACHES FROM CENTRAL CANADA. WILL STILL
SEE SOME LAKE EFFECT SNOW ONGOING...ON A MUCH DIMINISHED RATE...FOR
MORE NORTHWESTERLY WIND FAVORED AREAS WEDNESDAY NIGHT TO WEST-
NORTHWESTERLY WIND FAVORED AREAS THURSDAY...ESPECIALLY OVER THE
EAST WITH THE INCREASED FETCH.

THURSDAY NIGHT THROUGH SATURDAY...AS THE TROUGH AXIS SLIDES FARTHER
TO THE EAST...THE UPPER PENINSULA WILL BE JUST EAST OF THE
INFLECTION POINT BETWEEN THE TROUGH TO THE EAST AND THE RIDGE TO THE
WEST. THE GFS/EC ARE SHOWING A 500MB CLOSED LOW SLIDING ACROSS
HUDSON BAY THURSDAY NIGHT TO CENTRAL QUEBEC THROUGH SATURDAY
AFTERNOON. AS THIS HAPPENS...EXPECT A COUPLE SHORTWAVES TO ROTATE
THROUGH THE AREA WITH INCREASED MOISTURE WRAPPING THROUGH THE EAST
HALF OF THE CWA. THE MORE PRONOUNCED SHORTWAVE LOOKS TO SLIDE
THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY MORNING. 850MB
TEMPERATURES ARE PROGGED TO FALL EVEN FURTHER DURING THIS TIME
PERIOD POSSIBLY REACHING -30C. THIS WILL ALLOW FOR COLDER THAN
NORMAL TEMPERATURES DURING THIS TIME PERIOD ALONG WITH LAKE EFFECT
SNOW POTENTIAL FOR NORTH TO NORTH-NORTHWEST WIND FAVORED AREAS.
AGAIN...WITH THE BETTER MOISTURE SLIDING OVER THE EAST HALF OF THE
U.P. PLACED THE LIKELY POPS FOR LAKE EFFECT SNOW IN THOSE AREAS NEAR
LAKE SUPERIOR. THE AFOREMENTIONED COLD AIR MOVING IN WILL PRESS THE
FAVORED DGZ DOWN TO THE LOWEST LEVELS OF THE ATMOSPHERE AND IT WILL
BE FAIRLY SHALLOW TOO. THIS WOULD KEEP SNOWFLAKE SIZE FAIRLY SMALL
AND SNOW TO LIQUID RATIOS A BIT LOWER. THE THINGS HINTING TOWARD
HEAVIER SNOWFALL INTENSITY/ MORE PERSISTENT SNOW OVER THE EAST IS
THE INVERSION HEIGHTS PROGGED TO JUMP UP TO NEAR 8KFT OR SO ALONG
WITH INCREASED FORCING IN THAT LAYER THURSDAY NIGHT THROUGH FRIDAY
EVENING.

SATURDAY NIGHT...THE GFS AND EC ARE IN A BIT BETTER AGREEMENT ON
ANTICYCLONIC FLOW SLIDING INTO THE AREA ASSOCIATED WITH A SURFACE
RIDGE MOVING FROM SOUTH-CENTRAL CANADA AND THE NORTHERN PLAINS
EASTWARD INTO THE CWA. THIS...ALONG WITH DRIER AIR AND THE SLOW
APPROACH OF THE UPPER LEVEL RIDGE...SHOULD HELP TO DIMINISH THE LAKE
EFFECT SNOW ACROSS MOST OF THE CWA SATURDAY NIGHT. IF THIS WORKS OUT
AND THE SURFACE RIDGE IS OVERHEAD SATURDAY NIGHT...THE LIGHT WINDS
AND CLEARING SKIES WILL ALLOW TEMPERATURES TO FALL OFF SUBSTANTIALLY
ACROSS THE CWA WITH LOWS POSSIBLY FALLING INTO THE TEENS BELOW ZERO.

SUNDAY THROUGH MONDAY...MODELS DIVERGE DURING THIS TIME PERIOD AS
THE GFS TRIES TO BRING A COLD FRONT AND SHORTWAVE THROUGH THE UPPER
GREAT LAKES REGION DURING THIS TIME PERIOD WHILE THE EC KEEPS A
SURFACE RIDGE...DRIER AIR AND UPPER LEVEL 500MB RIDGE IN THE AREA
THROUGH MOST OF THIS TIME PERIOD. AT THIS POINT WENT WITH A
CONSENSUS OF THE MODELS GIVING ONLY SMALL CHANCES FOR LIGHT SNOW
LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 816 AM EST TUE FEB 9 2016

A CYCLONIC NNW FLOW OF COLD AIR WILL PERSIST THIS FORECAST PERIOD.
WITH DEEP MOISTURE ALSO LINGERING OVER THE W INTO THIS
AFTERNOON..EXPECT IFR/LIFR CONDITIONS TO PREDOMINATE AT IWD AND CMX.
CONDITIONS ARE LIKELY IMPROVE TO MVFR FOR AT LEAST A GOOD PORTION OF
THE TIME AT THOSE SITES BY LATE AFTERNOON FOLLOWING EXIT OF THE
DEEPER MOISTURE. BUT IFR CONDITIONS ARE POSSIBLE AT TIMES. FOR
SAW...MVFR CONDITIONS EARLY WILL GIVE WAY TO IFR CONDITIONS THIS
AFTERNOON AS THE LOW LEVEL FLOW VEERS TO A MORE FAVORABLE NRLY
DIRECTION IN THE PRESENCE OF MORE PERSISTENT DEEPER MOISTURE.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EST TUE FEB 9 2016

 THE SLOW MOVING LOW PRESSURE OVER SRN LAKE HURON WILL EXIT THE
LOWER GREAT LAKES TODAY. THIS WILL RESULT IN CONTINUED N WINDS TO 20
TO 30KNOTS WITH AND GALES TO 35KTS OVER N CENTRAL LAKE SUPERIOR TODAY
INTO THIS EVENING...WITH A FEW GALE FORCE GUSTS OVER PORTIONS OF THE
E HALF. FREEZING SPRAY WILL ALSO INCREASE WITH THE HEAVIEST FREEZING
SPRAY INTO WED. THE PRESSURE GRADIENT WILL SLOWLY WEAKEN AS AN
ELONGATED AREA OF HIGH PRESSURE STRETCHING ACROSS CENTRAL CANADA
THROUGH THE N PLAINS TUESDAY SLOWLY GAINS STRENGTH. EXPECT THIS AREA
OF STRONG AND COLD HIGH PRESSURE TO SLIDE OVER THE UPPER GREAT LAKES
REGION BY THE START OF THE NEXT WEEKEND.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST WEDNESDAY FOR MIZ006.

  LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     MIZ001-003.

  LAKE EFFECT SNOW WARNING UNTIL 4 PM EST /3 PM CST/ THIS
     AFTERNOON FOR MIZ002-009.

  LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST WEDNESDAY FOR MIZ005.

LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST /3 PM CST/ WEDNESDAY
     FOR LSZ162-263>266.

  GALE WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ264.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...KEC
AVIATION...- NONE -
MARINE...JLB



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