Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 100500
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1200 AM EST WED FEB 10 2016

.UPDATE...
ISSUED AT 1026 PM EST TUE FEB 9 2016

WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW TROF DEEPENING INTO THE
UPPER GREAT LAKES THIS EVENING. WITH TROF CONTINUING TO DEEPEN...
MODELS SHOW 12HR 500MB HEIGHT FALLS OF 20-80M ACROSS LAKE
SUPERIOR/UPPER MI DURING THE NIGHT...GREATEST OVER THE E HALF OF THE
AREA. UPSTREAM...12Z CWPL SOUNDING SHOWED A SHARP INVERSION AT ABOUT
875MB WHERE TEMP WAS -28C. 00Z CWPL SOUNDING SHOWED THAT THE
INVERSION HAD WEAKENED WITH A DEEP ISOTHERMAL LAYER NOW PRESENT FROM
AROUND 900MB TO AROUND 760MB. MOISTURE DEPTH HAS ALSO INCREASED TO
AROUND 760MB/6300FT. THERE HAS BEEN RATHER PERSISTENT 28+DBZ RETURNS
IN THE ONGOING SNOW BANDS EAST OF MARQUETTE...INDICATING 1+IN/HR
SNOW RATES. SINCE DEEPENING TROF AND UPSTREAM 00Z CWPL SOUNDING
SUPPORT AN INCREASE IN LES INTENSITY OVERNIGHT INTO WED MORNING...
LES WARNING HAS BEEN HOISTED FOR MARQUETTE/ALGER COUNTIES. SEEMS
REASONABLE THAT SOME AREAS WILL REACH/EXCEED 8IN/12HR OR 12IN/24HR
WARNING CRITERIA FOR HIGH SLR SNOWFALL.

18Z MODEL GUIDANCE AND HOURLY HRRR/RAP RUNS INDICATE SLIGHT VEERING
OF WINDS DURING THE NIGHT/WED MORNING WHICH WOULD SHIFT MDT/HVY SNOW
WESTWARD INTO MORE OF THE HIGH TERRAIN OF MARQUETTE COUNTY. WIND
FIELDS ACTUALLY LOOK QUITE FAVORABLE FOR DECENT SNOW AS N WIND OVER
THE LAKE ENCOUNTERS BACKED WIND OVER THE LAND. HAVE PAINTED 24HR
SNOW AMOUNTS ENDING 00Z THU OF 8 TO LOCALLY 12IN IN THAT AREA...BUT
GIVEN THE PERSISTENCE OF HVY SNOW SO FAR THIS EVENING IN EASTERN
MARQUETTE COUNTY...THE AREA AROUND SKANDIA/CARLSHEND WILL PROBABLY
END UP WITH THE MOST SNOW...14IN OR MORE DEPENDING ON HOW LONG THE
BAND LINGERS BEFORE SHIFTING W. IN ALGER COUNTY...RAN WARNING THRU
PREVIOUS ADVY TIMEFRAME....THOUGH SNOWFALL AFTER WED MORNING
PROBABLY WON`T REQUIRE ANYTHING MORE THAN ADVY. EXPECT GREATEST SNOW
TOTALS IN ALGER COUNTY TO BE IN THE WRN PORTION OF THE COUNTY.
FINALLY...WITH BLSN...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR...
THERE WILL NO DOUBT BE BRIEF WHITE-OUTS IN THE BANDS OF HVY SNOW.

OUT W...ENHANCING FACTORS INFLUENCING THE SNOW INTENSITY INTO NCNTRL
UPPER MI WILL BE WEAKER OVER WRN UPPER MI...SO NO MEANINGFUL CHANGES
WERE MADE TO FCST THERE.
&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 243 PM EST TUE FEB 9 2016

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE IN THE WESTERN U.S. AND
A CLOSED 500 MB LOW IN SOUTHERN ONTARIO WITH A TROUGH IN THE GREAT
LAKES REGION. THIS TROUGH CONTINUES TO MOVE SLOWLY EAST INTO THE
LOWER GREAT LAKES TONIGHT AS THE RIDGE MOVES INTO THE ROCKIES. NAM
SHOWS DEEPER MOISTURE AND 850-500 MB Q-VECTOR CONVERGENCE MOVING
OUT OF THE ERN CWA TONIGHT.

WINDS DO NOT CHANGE MUCH AND NEITHER DOES THE COLD AIR AMOUNT
THROUGH THIS FORECAST PERIOD...SO PERSISTENCE IS THE WAY TO GO WITH
THIS FORECAST. LOOKED AT 950 MB CONVERGENCE WINDS AND THEY STAY
STRONG UNTIL WED AFTERNOON ACROSS THE WESTERN CWA ALONG LAKE
SUPERIOR AND ACROSS MARQUETTE AND ALGER COUNTIES AND FOR THIS
REASON...EXTENDED THE ADVISORY FOR ALGER AND MARQUETTE COUNTIES
UNTIL 00Z WED AND WILL GO WITH AN ADVISORY FOR ONTONAGON AND GOGEBIC
COUNTIES AND KEEP NORTHERN HOUGHTON AND KEWEENAW COUNTIES IN AN
ADVISORY THROUGH THEN. LOOKING AT BUFKIT SOUNDINGS...INVERSION
HEIGHTS REMAIN BELOW 500 FEET THROUGH THIS WHOLE FORECAST PERIOD AS
WELL. OVERALL...DID NOT MAKE MANY BIG CHANGES TO THE GOING FORECAST
EXCEPT DID BUMP UP SNOW AND QPF AMOUNTS A BIT IN NORTHERLY LAKE
EFFECT SNOW BELTS AND HAVE CATEGORICAL POPS IN THOSE AREAS.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 348 PM EST TUE FEB 9 2016

NNW WINDS WILL CONTINUE WEDNESDAY NIGHT...BEFORE SHIFTING OUT OF THE
NW THURSDAY MORNING AND REMAINING OUT OF A MAINLY NW DIRECTION
THROUGH THE DAY FRIDAY. 850MB TEMPS STARTING OUT AROUND -22C...AND
ONLY BRIEFLY MODERATE SLIGHTLY TO AROUND -10C THURSDAY NIGHT BEFORE
MUCH COOLER AIR SLIDES BACK IN FOR FRIDAY. THE OVERALL PATTERN WILL
CONSIST OF A TROUGH LINGERING ACROSS LAKE SUPERIOR AS COLD/STRONG
CANADIAN HIGH PRESSURE SLOWLY SINKS ACROSS MANITOBA AND THE E
DAKOTAS/MN.

SUBTLE UPPER-LEVEL TROUGHING DIGGING SSE ACROSS THE CWA WEDNESDAY
NIGHT WILL VEER LOW-LEVEL WINDS ENOUGH TO SUPPORT ENHANCED LOW-LEVEL
CONVERGENCE BETWEEN MARQUETTE AND AU TRAIN. WITH GUSTY NNW WINDS AND
THERMO PROFILES STILL SUPPORTIVE OF MODEST LES...HAVE OPTED TO
EXTENDED THE LES ADVISORY FOR AT LEAST ALGER COUNTY THROUGH WED
NIGHT.

ENHANCING THE CONTINUED LAKE EFFECT SNOW SHOWERS WILL BE A TROUGH
SET UP ACROSS THE NW ONTARIO BORDER WITH MANITOBA AT 18Z THURSDAY.
EXPECT THE TROUGH TO SINK ACROSS LAKE SUPERIOR THURSDAY
NIGHT...BEFORE THE SFC TROUGH ITSELF PUSHES OVER FAR SE PORTIONS OF
ONTARIO FRIDAY AFTERNOON. A LINGERING THERMALLY-INDUCED TROUGH OVER
EASTERN LAKE SUPERIOR WILL AGAIN ENHANCE LOW-LEVEL CONVERGENCE AND
FOCUS LES INTO ALGER COUNTY FRI NIGHT INTO SAT. WITH A STRENGTHENING
PRESSURE GRADIENT DUE TO THE IMPINGING HIGH PRES...WINDS LOOKS TO BE
QUITE GUSTY THUR NIGHT INTO SAT. WHILE SPECIFICS ARE A BIT MUDDLED
AT THIS TIME...LES ADVISORY CONDITIONS MAY BE PRESENT AGAIN WITH THE
COMBINATION OF THE WIND AND FOCUSED LES BANDS.

A RATHER COLD 850MB CORE OF -30C WILL BRUSH THE CWA FRIDAY AFTERNOON
INTO SATURDAY MORNING. HAVE TRENDED TEMPS DOWNWARD A FEW DEGREES
DURING THIS PERIOD. WITH COLD TEMPS AND GUSTY WINDS...WIND CHILLS
WILL NEAR ADVISORY CRITERIA FOR MUCH OF THE CWA FRIDAY NIGHT.

LES QUICKLY SHIFTS TO THE EAST AS A SFC RIDGE CROSSES THE CWA SAT
NIGHT. CONDITIONS ARE SETTING UP FOR QUITE A CHILLY NIGHT WITH LIGHT
WINDS AND DRY CONDITIONS. THE ONE CAVEAT FOR VERY COLD CONDITION
WILL BE THE POSSIBILITY OF HIGH CLOUDS FILTERING ACROSS THE AREA
AHEAD OF LOW PRESSURE OVER THE NORTHERN PLAINS. HAVE TRENDED TEMPS
DOWNWARD...WITH TEENS BELOW ZERO INTERIOR WEST. AFTER DRY CONDITIONS
ON SUNDAY...TROUGHING WILL BRING LIGHT SNOW ACROSS THE REGION SUNDAY
NIGHT INTO MONDAY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1159 PM EST TUE FEB 9 2016

UNDER A NNW FLOW OF ARCTIC AIR ACROSS LAKE SUPERIOR...LAKE EFFECT
SNOW SHOWERS WILL BE THE RULE AT KIWD/KCMX/KSAW THRU THIS FCST
PERIOD...AND TYPICAL FOR LAKE EFFECT SNOW...CONDITIONS WILL BE
HIGHLY VARIABLE. PREVAILING CONDITIONS WILL LIKELY BE IFR...BUT
EXPECT PERIODS OF LIFR AND MVFR. LIFR CONDITIONS SHOULD BE MORE
LIKELY TO OCCUR AT KSAW LATE OVERNIGHT/EARLY THIS MORNING AS SLIGHTLY
VEERING WINDS SHIFT HEAVIER SNOW SHOWERS WESTWARD TO KSAW. SOMEWHAT
DRIER AIR AND A FALLING INVERSION SHOULD LEAD TO IMPROVING CONDITIONS
THIS AFTN WITH A TREND TO PREVAILING MVFR.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 243 PM EST TUE FEB 9 2016

GALE FORCE GUSTS WILL CONTINUE INTO THIS EVENING OVER NORTH CENTRAL
LAKE SUPERIOR. NEXT GALES LOOK TO BE THU NIGHT AND FRI ACROSS LAKE
SUPERIOR AS NEXT SHOT OF COLD AIR MOVE IN AND PRESSURE GRADIENT
TIGHTENS UP AGAIN. FREEZING SPRAY WILL ALSO INCREASE WITH THE
HEAVIEST FREEZING SPRAY INTO WED.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
     FOR MIZ001>003-009.

  LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005.

  LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ006.

LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST THURSDAY FOR
     LSZ265>267.

  HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST /3 PM CST/ WEDNESDAY
     FOR LSZ162-263-264.

  GALE WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ264.

LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...ROLFSON
SHORT TERM...07
LONG TERM...KF/KLUBER
AVIATION...ROLFSON
MARINE...07


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