Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 152012
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
312 PM EST MON DEC 15 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 311 PM EST MON DEC 15 2014

UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER THE CENTRAL
PLAINS AND A NORTHERN TROUGH OVER SOUTH CENTRAL CANADA THIS MORNING.
THERE IS ALSO RIDGING OVER THE ERN U.S. AND THE ROCKIES. THE CLOSED
LOW AND THE TROUGH TRY TO MERGE INTO ONE SYSTEM AS THE LOW HEADS
NORTHEAST AND THE TROUGH DIGS SOUTHEAST TODAY. THE NORTHERN STREAM
SYSTEM TAKES OVER AS THE STRONGER SYSTEM TUE AFTERNOON. NAM...GFS
AND ECMWF SHOW 850-500 MB Q-VECTOR CONVERGENCE REMAINING OVER THE
AREA THROUGH TUE AFTERNOON.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. COLDER AIR
COMES IN TONIGHT WHICH WILL START TO GET RID OF THE FOG...SO WILL
LET DENSE FOG ADVISORY EXPIRE AT 8 PM. FOLLOWED A BLEND OF THE
ECMWF...GFS AND NAM FOR THIS FORECAST FOR PCPN TYPES AND WAS NOT
MUCH DIFFERENT FROM GOING FORECAST AND SNOW DOES NOT REALLY GET
STARTED ACROSS THE WEST UNTIL AFTER MIDNIGHT. DID NOT WORRY TOO MUCH
ABOUT SLEET OR FREEZING RAIN AS THIS DID NOT LOOK LIKE IT WOULD LAST
VERY LONG AT ALL AND KEPT THE PCPN GOING FROM RAIN TO SNOW FOR THIS
FORECAST. BROUGHT THE COLD AIR IN A LITTLE SLOWER THAN PREVIOUS
FORECAST AND DID NOT MAKE TOO MANY CHANGES TO THE GOING TEMPERATURES
AND DID NOT MAKE TOO MANY CHANGES TO POPS OR QPF AMOUNTS EITHER.
SNOW AMOUNTS LOOK TO BE 1-4 INCHES ON TUESDAY WITH THE SNOW REALLY
STARTING UP LATE IN THE AFTERNOON. AMOUNTS LOOK TO BE LIGHT UNTIL
THEN AND WILL NOT GO WITH ANY ADVISORIES AT THIS TIME.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 305 AM EST MON DEC 15 2014

THE LONG TERM PART OF THE FORECAST WILL MARK A RETURN TO WEATHER
MORE LIKE EARLY-MID DECEMBER THAN WHAT WAS SEEN OVER THE PAST COUPLE
DAYS. MUCH OF THE FOCUS ON THE FORECAST WILL LIE WITH THE SNOWFALL
FORECAST FOR TUESDAY INTO WEDNESDAY NIGHT...BEFORE HIGH PRESSURE
BUILDS BACK INTO THE AREA FOR THE END OF THE WORK WEEK AND THE
FIRST PART OF NEXT WEEKEND.

AT 12Z TUESDAY...THERE WILL BE TWO SHORTWAVES NEAR THE GREAT LAKES
REGION...WITH THE FIRST WAVE LOCATED OVER THE LOWER GREAT LAKES AND
THE SECOND WAVE FARTHER TO THE NORTHWEST AND STRETCHING FROM
SOUTHERN HUDSON BAY THROUGH NORTHERN MINNESOTA. WHILE THERE ARE
STILL SOME SUBTLE DIFFERENCES IN THE MODELS AND HOW THEY HANDLE THE
INTERACTION OF THESE TWO FEATURES...IN GENERAL THEY ARE PRETTY
SIMILAR IN THE EVOLUTION THROUGH THURSDAY. AT THE SURFACE AT 12Z ON
TUESDAY...THERE WILL BE A 1004MB LOW OVER SOUTHERN LAKE MICHIGAN
WITH A 1009MB TROUGH STRETCHING NORTH THROUGH NORTHERN LOWER
MICHIGAN AND INTO EASTERN ONTARIO. MEANWHILE...THE 850MB TROUGH
WILL BE SLIGHTLY BACK TO THE WEST AND WORKING ITS WAY ACROSS UPPER
MICHIGAN AND LOCATED OVER THE EAST CENTRAL U.P.. EXPECT LIGHT
PRECIPITATION TO BE OCCURRING ACROSS THE CWA WITH SNOW BEHIND THE
FRONT AND RAIN/FOG EAST OF A LINE FROM GRAND MARAIS TO RAPID RIVER.
WITH THE COLD AIR CONTINUING TO PUSH EAST THROUGH THE REST OF
EASTERN UPPER MICHIGAN ON TUESDAY...EXPECT A CHANGE TO SNOW TO
OCCUR THERE. FOR TUESDAY INTO TUESDAY NIGHT...THE LOW WILL MOVE
NORTHEAST TO SOUTHWEST QUEBEC BY WEDNESDAY MORNING...WHILE LEAVING
A MID LEVEL AND SURFACE TROUGH BACK WEST OVER THE UPPER GREAT LAKES
REGION AND TIED TO THE SECONDARY SHORTWAVE SLOWLY DROPPING
SOUTH-SOUTHEAST INTO NORTHERN WISCONSIN BY WEDNESDAY MORNING. AS
THAT OCCURS...THE DEEPER MOISTURE WILL MOVE EAST OUT OF THE
WESTERN U.P. AND FOCUS OVER THE NORTHEASTERN U.P. AND EASTERN LAKE
SUPERIOR AS THE LOW LEVEL TROUGH PIVOTS THERE. THUS...WOULD EXPECT
THE POTENTIAL FOR LIGHT TO OCCASIONALLY MODERATE SNOW TO CONTINUE
THERE TUESDAY NIGHT AND EVEN INTO WEDNESDAY UNTIL THE TROUGH
PULLS OUT WEDNESDAY NIGHT.

FARTHER WEST...THE COLDER AIR SURGING INTO THE AREA (850MB TEMPS
FALLING TO -15C BY 00Z WEDNESDAY) WILL LEAD TO LAKE ENHANCED SNOW
INITIALLY AND THEN TRANSITIONING TO LAKE EFFECT AS THE DEEPER
MOISTURE PIVOTS OUT. LOW LEVEL WINDS WILL GENERALLY BE OUT OF THE
NORTH-NORTHWEST (AROUND 340 DEGREES) AS THE SURFACE-850MB TROUGH
PIVOTS OVER EASTERN LAKE SUPERIOR. WITH THE 850MB TEMPS BEING NEAR
THE TOP OF THE CLOUD LAYER...LIFT WITHIN THE DGZ WILL BE LIMITED AND
EXPECT SNOW RATIOS TO BE IN THE 12 TO 1 RANGE INITIALLY OVER THE FAR
WEST AND RISING TO THE MID TEENS. BUT HEADING CLOSER TO THE
TROUGH AND MORE INTO THE LAKE ENHANCED PRECIPITATION (FROM THE
KEWEENAW THROUGH NORTHERN CENTRAL UPPER MICHIGAN) WOULD THINK THAT
RATIOS WOULD BE A LITTLE HIGHER (UPPER TEENS) DUE TO THE LARGER AREA
THE CLOUD WILL BE IN THE DGZ. WILL CONTINUE TO SHOW DEFINITE POPS
OVER THE NORTH-NORTHWEST WIND FAVORED LOCATIONS TUESDAY AFTERNOON
THROUGH WEDNESDAY MORNING. SNOWFALL AMOUNTS FROM SYNOPTIC AND LAKE
ENHANCED/EFFECT GENERALLY AMOUNT TO 1-2 INCHES EVERY 6 HOURS OVER
THE NORTHERN TIER OR COUNTIES AND ALSO SCHOOLCRAFT AND NORTHEAST
DELTA COUNTIES. WOULD EXPECT THE HIGHEST AMOUNTS TO OCCUR OVER THE
KEWEENAW AND THEN SOUTHEAST THROUGH THE HURON MOUNTAINS TO CHATHAM
AND NEWBERRY. WHILE THE RATES DON/T LOOK TO BE THAT HIGH...THE
PERSISTENT NATURE OF THE SNOW WOULD LEAD TO AMOUNTS FROM TUESDAY
MORNING THROUGH WEDNESDAY NIGHT TO BE IN THE 5-10 INCH RANGE IN
THE HIGHEST AREAS. THEREFORE...WILL CONTINUE TO MENTION THE SNOW
POTENTIAL IN THE HWO WITH A LONG DURATION ADVISORY LIKELY
NEEDED IN THE FUTURE.

MODELS ARE CONSISTENT ON THE SURFACE-850MB TROUGH DROPPING
SOUTHEAST AND WEAKENING WEDNESDAY AFTERNOON/NIGHT...ALLOWING DRIER
AND WARMER AIR TO MOVE INTO THE AREA ON THE EAST SIDE OF THE HIGH
NEAR KINL. THIS WILL LEAD TO A VERY QUICK END TO THE LAKE
EFFECT/ENHANCED SNOW LATE WEDNESDAY NIGHT INTO THURSDAY MORNING AND
WILL FOLLOW THAT IDEA FOR THE POPS. THAT HIGH PRESSURE WILL LEAD TO
DRY AND MOSTLY CLEAR CONDITIONS FOR THE REST OF THE WORK WEEK.
MODELS DIVERGE HEADING INTO THE WEEKEND...BUT THE GENERAL IDEA IS
FOR A SHORTWAVE AND WEAK SURFACE TROUGH TO SLIDE THROUGH THE AREA AT
SOME POINT DURING THE WEEKEND. THEREFORE...WILL SHOW INCREASING
CLOUDS ON SATURDAY AND SLIGHT CHANCE POPS FOR SATURDAY NIGHT INTO
SUNDAY. HIGHS ON WEDNESDAY LOOK TO BE A TOUCH BELOW NORMAL
(LOW-MID 20S)...BUT THEN EXPECT A GRADUAL WARM UP TO ABOVE NORMAL
VALUES BY SATURDAY (UPPER 20S AND LOWER 30S) WITH THE RELATIVELY
WARM NORTHERLY FLOW.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1208 PM EST MON DEC 15 2014

CONTINUED LOW VIS/LOW CIG EVENT THROUGH THIS FORECAST PERIOD AT ALL
SITES WITH CONDITIONS REMAINING IN LIFR/VLIFR THROUGH LATE TONIGHT
BEFORE COLDER AIR CHANGES THE LIQUID PRECIPITATION OVER TO SNOW.
WILL GET GUSTY WITH NORTH WINDS WITH THE COLD AIR AND ONCE COLD AIR
ARRIVES...CONDITIONS WILL SLOWLY IMPROVE TO IFR/LIFR.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 311 PM EST MON DEC 15 2014

COLDER AIR WILL MOVE INTO THE AREA THIS EVENING REDUCING THE FOG.
EXPECT N-NW WINDS OF 20-30KTS LATE THIS EVENING INTO EARLY TUESDAY
EVENING. A FEW GALE FORCE GUSTS TO 35KTS WILL BE POSSIBLE AND THIS
WILL BE THE STRONGEST WIND FORECAST FOR THE ENTIRE FORECAST. NO
GALES SEEN ANYTIME SOON OTHERWISE.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  DENSE FOG ADVISORY UNTIL 8 PM EST /7 PM CST/ THIS EVENING FOR
     MIZ001>007-009>014-084-085.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
  DENSE FOG ADVISORY UNTIL 8 PM EST THIS EVENING FOR LMZ221-248-
     250.

&&

$$

SHORT TERM...07
LONG TERM...SRF
AVIATION...07
MARINE...07





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