Area Forecast Discussion
Issued by NWS Marquette, MI

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141
FXUS63 KMQT 082006
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
306 PM EST MON FEB 8 2016

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 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...(TUESDAY THROUGH SUNDAY)
ISSUED AT 501 AM EST MON FEB 8 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 TEMPERATURES BY
FRIDAY AND SATURDAY.

TUESDAY AND TUESDAY NIGHT...THE UPPER LEVEL TROUGHING WILL REMAIN IN
PLACE ACROSS THE EASTERN CONUS THROUGH THIS TIME PERIOD WHILE THE
SURFACE LOW SLIDES SLOWLY EAST TO NEAR LAKE HURON BY LATE TUESDAY
NIGHT. THIS WILL KEEP ALL OF THE U.P. IN NORTH TO NORTH-NORTHWEST
WIND FLOW. 850MB TEMPERATURES WILL STEADILY COOL ON CAA INTO THE
AREA WITH 850MB TEMPERATURES DROPPING TO AROUND -22C/-25C BY TUESDAY
EVENING INTO TUESDAY NIGHT. THIS WILL HAPPEN AS A SHORTWAVE AND
ASSOCIATED SHOT OF COLD AIR SLIDE INTO THE AREA. THIS WILL KEEP LAKE
EFFECT SNOW IN THE FORECAST...HEAVIEST IN THE NORTH TO NORTH-
NORTHWEST WIND FAVORED LOCATIONS. THE BEST SNOWFALL
POTENTIAL/HIGHEST SNOW TO LIQUID RATIOS DURING THIS TIME PERIOD
WOULD BE EARLY TUESDAY MORNING OVER THE FAR WEST AND THE KEWEENAW
PENINSULA AND THROUGH MUCH OF THE DAY OVER THE CENTRAL AND EAST.
THIS TRANSITION WILL FOLLOW THE DEEPER MOISTURE AND MUCH COLDER AIR
WORKING IN DURING THE AFTERNOON FROM THE WEST. MOISTURE WILL BE IN A
DEEPER LAYER OF THE DGZ EARLY IN THE MORNING OVER THE WEST WITH
INVERSION HEIGHTS PROGGED TO BE AROUND 4-6KFT. MOST OF THE MOISTURE
LATE MORNING INTO THE  AFTERNOON WILL BE BELOW 3-4KFT WITH MUCH
DRIER AIR SLIDING IN ALOFT OVER THE WEST. THE DGZ WILL BECOME MUCH
SHALLOWER THROUGH THE DAY OVER THE FAR WEST AS THE VERY CHILLY AIR
SLIDES IN ALOFT. NORTH CENTRAL AND EASTERN AREAS OF THE U.P. WILL
SEE THE DEEP MOISTURE LINGERING AROUND THROUGH THE DAY WITH
INVERSION HEIGHTS STAYING AROUND 5-7KFT AND A DEEPER CONVECTIVE
CLOUD LAYER IN THE DGZ. THIS SHOULD HELP TO PRODUCE MODERATE SNOW
SHOWERS THROUGHOUT THE DAY IN THESE AREA GIVEN THE POTENTIAL FOR
LARGER SNOWFLAKE SIZES. TUESDAY EVENING INTO TUESDAY NIGHT...THE
MUCH COLDER AIR SLIDING IN ALOFT WILL PLACE MUCH OF THE CONVECTIVE
CLOUD LAYER ACROSS THE U.P. COLDER THAN THE IDEAL DGZ...WHICH WILL
PROVIDE MUCH SMALLER SNOWFLAKES AND LOWER SNOW TO LIQUID RATIOS. THE
WESTERN HIGH TERRAIN COULD SEE ANOTHER 1 TO 4 INCHES TUESDAY INTO
TUESDAY NIGHT WHILE NORTH CENTRAL 3 TO 6 INCHES WITH THE HIGHEST
TOTALS EXPECTED OVER THE HIGH TERRAIN OF MARQUETTE AND BARAGA
COUNTIES. LATER SHIFTS WILL PROBABLY NEED TO EXPAND THE ADVISORIES
EASTWARD INTO BARAGA...MARQUETTE AND ALGER COUNTIES FOR THE TUESDAY
AND TUESDAY NIGHT TIME FRAME.

WEDNESDAY THROUGH THURSDAY...THE 500MB TROUGH WILL REMAIN DUG IN
OVER THE EASTERN CONUS WITH CONTINUED RIDGING OVER THE WESTERN
CONUS. 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 CHILLY AIR AT 850MB WILL STILL
BE IN PLACE KEEPING SLR VALUES LOWER THAN WHAT THEY WOULD BE IF THE
MOISTURE AND CONVECTIVE LAYER WERE IN THE PREFERRED DGZ. 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 INTO THURSDAY.

THURSDAY NIGHT THROUGH SATURDAY...AS THE TROUGH AXIS SLIDES FARTHER
TO THE EAST...THE UPPER PENINSULA WILL BE ON 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. 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 NORTHWEST WIND FAVORED AREAS.
AGAIN...WITH THE BETTER MOISTURE SLIDING OVER THE EAST HALF OF THE
U.P. PLACED THE BETTER CHANCES OF LAKE EFFECT SNOW IN THOSE AREAS
NEAR LAKE SUPERIOR. THIS SNOW SHOULD NOT AMOUNT TO MUCH THOUGH AS
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.

SATURDAY NIGHT INTO SUNDAY...MODELS BEGIN TO DIVERGE A BIT WHICH IS
NOT UNCOMMON FOR THE LATTER PART OF THE EXTENDED FORECAST. THE GFS
TRIES TO BRING A COLD FRONT AND SHORTWAVE THROUGH THE UPPER GREAT
LAKES REGION DURING THIS TIME PERIOD WHILE THE EC PUSHES A SURFACE
RIDGE AND BRIEF UPPER LEVEL 500MB RIDGE INTO THE AREA THROUGH THIS
TIME PERIOD. AT THIS POINT WENT WITH A CONSENSUS OF THE MODELS
GIVING ONLY SMALL CHANCES FOR LIGHT SNOW LATE IN THE WEEKEND.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1151 AM EST MON FEB 8 2016

AS A CYCLONIC NNW FLOW OF COLD AIR PERSISTS ACROSS WRN UPPER MI
THROUGH TONIGHT...EXPECT SN AND MAINLY IFR/LIFR CONDITIONS TO
PREDOMINATE. THERE MAY BE A FEW PERIODS WITH MVFR
CONDITIONS...ESPECIALLY AT SAW WHERE THE NNW WINDS WILL BE LESS
FAVORABLE FOR THE STRONGER LAKE ENHANCED OR LAKE EFFECT SNOW.
&&

.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...
  WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ TUESDAY FOR
     MIZ001>003-009.

LAKE SUPERIOR...
  GALE WARNING FROM 7 PM THIS EVENING TO 10 PM EST TUESDAY FOR
     LSZ264.

LAKE MICHIGAN...
NONE.
&&

$$

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



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