Area Forecast Discussion
Issued by NWS Marquette, MI

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579
FXUS63 KMQT 091000
AFDMQT

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

.UPDATE...
ISSUED AT 956 PM EST MON FEB 8 2016

RECENTLY RECEIVED SOME REPORTS OF UP TO 9 INCHES OF SN IN THE
IRONWOOD AREA...WITH SN FALLING AT AN INCH OR TWO PER HR. GIVEN THE
FAVORABLE CYC UPSLOPE NNW FLOW/SHARP LLVL CNVGC FCST TO PERSIST IN
THIS AREA THRU THE NGT BY SEVERAL HI RES MODELS...LINGERING DEEP
MSTR INDICATED ON WV IMAGERY...FALLING H85 TEMPS TOWARD -20C BY 12Z
TUE...AND FAVORABLE SN/WATER RATIOS WITH DGZ IN THE LOWEST COUPLE
THOUSAND FEET AGL THAT COINCIDES WITH SHARP LLVL UVV MAX...OPTED TO
UPGRADE THE WINTER WX ADVY TO AN LES WARNING FOR GOGEBIC AND
ONTONAGON COUNTIES DESPITE RATHER LO INVRN BASE NEAR H9 SHOWN ON 00Z
INL RAOB AND FCST SDNGS FOR THE WRN CWA AS WELL AS LLVL DRY AIR OVER
THE MN ARROWHEAD UPWIND OF LK SUP. EXPECT STORM TOTAL SN TO APRCH 18
INCHES IN SOME PLACES. THE NNW FLOW WL NOT BE AS FVRBL FOR THE
KEWEENAW...SO HELD ON TO AN ADVY FOR THAT AREA.
&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 710 PM EST MON FEB 8 2016

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE ON THE WEST COAST AND A
CLOSED 500 MB TROUGH OVER THE CENTRAL U.S. AND UPPER GREAT LAKES
REGION. THE CLOSED 500 MB LOW MOVES FROM CENTRAL LAKE MICHIGAN THIS
MORNING TO SW LOWER MICHIGAN BY THIS EVENING AND TO SE OF DTW BY 12Z
TUE AND TO NE OF CLE BY 00Z WED.

NAM HAS SOME WEAK 850-500 MB Q-VECTOR CONVERGENCE AND SOME DEEPER
MOISTURE MOVING THROUGH THE CWA THROUGH TUE. GFS AND ECMWF ARE
FAIRLY SIMILAR AS WELL AND USED A BLEND OF THESE MODELS FOR THIS
FORECAST. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST. CONVERGENCE IN THE LOW LEVELS WILL CONTINUE IN NORTH WIND
LAKE EFFECT SNOW BELTS THROUGH THIS FORECAST PERIOD...BUT INVERSION
HEIGHTS DO FALL BY 21Z TUE DOWN TO ABOUT 6000 FEET IN THE WESTERN
CWA. 850 MB TEMPERATURES DO FALL TO -20C TO -22C BY 00Z WED AND ARE
AT -8C TO -16C BY 00Z TONIGHT WITH THE WARMEST READINGS OVER ERN
LAKE SUPERIOR. LAKE-850 MB DELTA-T WOULD BE FROM 11C TO 19C BY 00Z
TONIGHT WHICH IS ENOUGH FOR LAKE EFFECT SNOW. LOOKED AT BUFKIT
SOUNDINGS OFF THE NAM AND THERE IS IN BOTH THE 12Z CYPL AND 12Z KINL
SOUNDING SOME DRIER AIR IN THE LOWER LEVELS WITH A SMALL INVERTED-V
SOUNDING AT THE LOWEST LEVELS AND NAM BUFKIT CONTINUES TO SHOW THIS
DRY AIR IN THE LOW LEVELS THIS FORECAST PERIOD WITH INVERSION
HEIGHTS FALLING TUE AFTERNOON. WITH THE INVERTED-V LOOK AND COOLING
ALOFT WITH TIME...LAKE EFFECT SNOW WILL CONTINUE TO BE FAIRLY
PERSISTENT AND DECIDED TO CONTINUE THE WINTER WEATHER ADVISORIES
ALONG LAKE SUPERIOR FROM THE LAKE SUPERIOR SHORELINE COUNTIES UP
THROUGH THE KEWEENAW PENINSULA. EAST OF THERE...THE LOW LEVEL
CONVERGENCE IS NOT AS STRONG. OVERALL...DID NOT MAKE TOO MANY
CHANGES TO THE GOING FORECAST.

.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 146 AM EST TUE FEB 9 2016

A CYC NNW FLOW OF COLD AIR WL PERSIST THIS FCST PERIOD. WITH DEEP
MSTR ALSO LINGERING OVER THE W INTO THIS AFTN...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 IN THE AFTN FOLLOWING EXIT OF DEEPER MSTR. BUT IFR CONDITIONS
ARE POSSIBLE AT TIMES. FOR SAW...VFR/MVFR WX EARLY WL GIVE WAY TO
IFR CONDITIONS LASTER THIS MRNG AS THE LLVL FLOW VEERS TO A MORE
FAVORABLE DUE N DIRECTION IN THE PRESENCE OF MORE PERSISTENT DEEPER
MSTR.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 305 PM EST MON FEB 8 2016

THE SLOW MOVING LOW PRESSURE SYSTEM WILL MOVE OVER N LOWER MI
TODAY...AND EXIT ACROSS LAKE HURON AND THE LOWER GREAT LAKES ON
TUESDAY. THE RESULT MARINE WILL BE INCREASING N WINDS TO 20 TO
30KNOTS WITH AND GALES TO 35KTS OVER N CENTRAL LAKE SUPERIOR TODAY-
TUESDAY EVENING...WITH A FEW GALE FORCE GUSTS OVER PORTIONS OF THE E
HALF TUESDAY-TUESDAY EVENING. FREEZING SPRAY WILL ALSO INCREASE WITH
THE HEAVIEST FREEZING SPRAY FROM LATE TONIGHT 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.
&&

$$

UPDATE...KC
SHORT TERM...07
LONG TERM...KEC
AVIATION...KC
MARINE...07



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