000
FXUS63 KMQT 062349
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
649 PM EST MON FEB 6 2012

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 432 PM EST MON FEB 6 2012

FOCUS IN THE SHORT TERM IS ON INCOMING COLD AIR MASS FOLLOWING COLD
FRONT WHICH IS CURRENTLY BISECTING THE UPPER PENINSULA.
STRATUS/STRATOCU HAS BEEN PUSHING S WITH THE FRONT INTO UPPER MI...
BUT SO FAR...THERE APPARENTLY HAS BEEN NO PCPN YET. ALTHOUGH OBS TO
THE N OF THE LAKE HAVE INDICATED SOME -SN/FLURRIES TODAY...DON`T
HAVE TO GO TOO MUCH FARTHER N OF THE LAKE BEFORE CLOUDS CLEAR
OUT...SUGGESTING AIR MASS DRIES OUT FAIRLY QUICKLY.

OVERALL...INHERITED FCST APPEARED TO HAVE A GOOD HANDLE ON THE
SCENARIO TONIGHT INTO TUE. THERE ARE SEVERAL FACTORS WHICH WILL KEEP
THIS PERIOD OF LES FROM BEING A HEADLINE EVENT. FIRST...INVERSIONS
INITIALLY ONLY AROUND 4-5KFT FALL TO 3KFT OR LWR BY 12Z TUE.
UPSTREAM 12Z RAOBS AT CWPL/CYQD SUGGEST INITIAL INVERSION COULD
ACTUALLY BE A LITTLE LWR THAN INDICATED BY MODELS. SECOND...AIR MASS
DRIES OUT QUICKLY...AND AFTN SATELLITE IMAGERY SUGGESTS THAT WILL IN
FACT BE THE CASE. THIRD...LARGE SCALE FLOW WHICH IS NEVER MUCH
CYCLONIC BECOMES MUCH MORE ANTICYCLONIC TUE MORNING. ONLY REAL
POSITIVE IS THAT THE DENDRITIC SNOW GROWTH TEMP LAYER WILL FALL INTO
THE TERRAIN ENHANCED UPWARD MOTION LAYER OVERNIGHT INTO TUE MORNING
TO HELP FLUFF UP THE SNOW/INCREASE SNOW TO WATER RATIOS. GIVEN THE
NEGATIVES...DO NOT EXPECT ACCUMULATIONS TO REACH ADVY CRITERIA EVEN
OVER THE NCNTRL HIGHER TERRAIN WHICH WILL BE MOST FAVORED FOR
GREATEST ACCUMULATIONS UNDER NNE LOW-LEVEL WINDS. IN GENERAL...
ACCUMULATIONS TONIGHT SHOULD BE ON THE ORDER OF 1-4 INCHES OVER THE
FAR W AND NCNTRL AND 1-2 INCHES OVER THE KEWEENAW AND FOR AREAS E OF
MUNISING. MIGHT SEE A 5 INCH AMOUNT OVER THE HURON MTNS. OVER THE
W...LOW-LEVEL FLOW IS MORE DIFFLUENT (MORE NE CLOSE TO THE LAKE AND
MORE N INLAND)...SO MAIN LES SHOULD BE CONFINED CLOSER THE SHORE
WITH ONLY OCNL -SHSN/FLURRIES FARTHER INLAND.

LES WILL WIND DOWN QUICKLY W TO E TUE AS INVERSION FALLS TO 3KFT AND
AIR MASS CONTINUES TO DRY. PROBABLY STARTING TO GET INTO THE TIME OF
YEAR WHERE INCREASING SUN ANGLE BEGINS TO HAVE A DISRUPTING AFFECT
ON LES AS WELL. SO...WITH AREAS UPWIND OF THE LAKE SUNNY...DAYTIME
HEATING WILL PROBABLY ASSIST IN DISRUPTING/WEAKENING LES THRU THE
DAY. ADDITIONAL SNOW ACCUMULATIONS TUE MORNING SHOULD BE ON THE
ORDER OF AN INCH TO POSSIBLY 2 IN A FEW SPOTS.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 432 PM EST MON FEB 6 2012

FCST MODELS ARE IN GOOD AGREEMENT WITH THE LARGE 500MB LOW CURRENTLY
SPINNING OVER FAR NORTHERN HUDSON BAY TO DIP SOUTHWARD AND ROTATE
ACROSS CENTRAL QUEBEC THROUGH AT LEAST FRIDAY. AT THE SFC...HIGH
PRESSURE CENTERED OVER THE DAKOTAS AT 00Z WEDNESDAY WILL CONTINUE TO
DIVE DUE SOUTH...AS THE MAIN SFC TO 500MB LOW SINKS ACROSS QUEBEC.
AS A RESULT...SFC WINDS WILL REMAIN IN THE 270 TO 360 DEGREE
QUADRANT...WITH THE BEST POTENTIAL FOR LAKE EFFECT SNOW SHOWERS
LINGERING NEAR LAKE SUPERIOR. THEY DO HIGHLIGHT A COLD FRONT SET UP
ACROSS NORTHERN LAKE SUPERIOR THURSDAY MORNING.

THE HANDLING OF THE SMALLER SCALE FEATURES BEYOND THURSDAY MORNING
BECOME TRICKIER AS FCST MODELS BEGIN TO DIVERGE. THIS LEADS TO A
HIGHER CONFIDENCE IN THE ONGOING FORECAST DIMINISHING TO LESS THAN
AVERAGE BY THURSDAY AFTERNOON. THE 06/12Z RUN OF THE CANADIAN LOOKS
TO BE ON THE SLOW SIDE OF SOLUTIONS...WITH THE GFS/NAM/ECMWF
BRINGING THE OLD FRONT ACROSS CENTRAL UPPER MICHIGAN THURSDAY
AFTERNOON. THE CANADIAN WOULD HAVE IT JUST PUSHING ACROSS THE
KEWEENAW PENINSULA AND THROUGH FAR WESTERN UPPER MICHIGAN. LIKE THE
CURRENT COLD FRONT DIPPING SOUTH ACROSS THE REGION...THERE IS NOT
MUCH TO GET TOO IMPRESSED ABOUT SNOW WISE. THE LAKE EFFECT SNOW
PARAMETER OFF BOTH THE ECMWF AND GFS DO NOT LOOK TOO IMPRESSIVE WITH
THE COLD AIR AND FAVORABLE WINDS SLIDING IN ON NW WINDS THURSDAY
AFTERNOON...WHICH SHOULD SLOWLY BECOME NORTHERLY BY DAYBREAK FRIDAY.
850MB TEMPS FALL FROM -12C NEAR THE LAKE SUPERIOR SHORELINE...TO
-21C BY 12Z FRIDAY. THE MAIN CONCERNS TO MODERATE SNOW ACCUMULATIONS
LOOK TO BE THE CHANGING WINDS OVER LAKE SUPERIOR...LIMITING FETCH
AND INCREASING THE DISRUPTION OF CONSISTENT BANDS OF LAKE EFFECT
SNOW SHOWERS. WHILE SNOW SHOWERS WILL PERSIST...THEY SHOULD BE
MOVING ENOUGH TO LIMIT SIGNIFICANT ACCUMULATIONS. HAVE KEPT THE
MENTION OF LIGHT TO MODERATE SNOW SHOWERS IN THE HWO FOR N-NW
FAVORED WIND AREAS...BUT CONTINUED TO KEEP IT OUT OF THE EHWO
GRAPHICS AT THIS TIME. GIVEN ALL THE COLD AIR SLIDING IN...HIGH
TEMPS ON FRIDAY WILL BE DOWN RIGHT CHILLY COMPARED TO THE LAST WEEK
OR SO...TOPPING OUT IN THE TEENS...BEFORE MODERATING SLIGHTLY TO
NEAR NORMAL VALUES SUNDAY...AND REBOUNDING TO ABOVE NORMAL AGAIN
/AROUND 30F/ MONDAY.

YET ANOTHER SIGNIFICANT SFC HIGH OVER CENTRAL CANADA WILL SHIFT
SOUTHWARD ACROSS MANITOBA DURING THE DAY FRIDAY...ALLOWING THE SFC
TROUGH OVER MI TO CONTINUE ITS SOUTHWARD PROGRESSION. ANOTHER BLAST
OF COLD AIR BELOW -25C MAY SLIDE INTO THE REGION SATURDAY NIGHT INTO
SUNDAY...WITH ACCUMULATING SNOW ON NORTHERLY WINDS SUNDAY.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 648 PM EST MON FEB 6 2012

NORTHERLY WINDS BEHIND A COLD FRONT...HAVE BROUGHT IN MVFR CIGS
ACROSS THE AREA AND THE BEGINNINGS OF SOME LAKE EFFECT SNOW SHOWERS.
UPSLOPE NRLY FLOW WILL FAVOR KIWD AND KSAW FOR THE LOWEST VSBYS IN
LES...POSSIBLY AS LOW AS IFR ONCE THE COLDEST AIR AND GREATEST
OVERWATER INSTABILITY OCCURS LATE THIS EVENING AND OVERNIGHT.
DIMINISHING OF LAKE EFFECT SHSN/IMPROVEMENT EXPECTED AT ALL SITES
TUE MORNING AS FLOW BECOMES INCREASINGLY ANTICYCLONIC...THE
SUBSIDENCE INVERSION LOWERS AND DRIER AIR ARRIVES. EXPECT CLEARING
FROM THE WEST BY MID-LATE TUE AFTERNOON AS FLOW BACKS MORE NW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EST MON FEB 6 2012

IN THE WAKE OF A PASSING COLD FRONT...EXPECT NORTHERLY WINDS OF
20-30KT TONIGHT ACROSS MUCH OF LAKE SUPERIOR. INCOMING COLDER
AIR/GUSTY WINDS/HIGHER WAVES WILL BRING FREEZING SPRAY AS WELL
TONGIHT...WITH HVY FREEZING SPRAY OVER PORTIONS OF W AND CNTRL LAKE
SUPERIOR. CONDITIONS WILL IMPROVE TUE WITH THE ARRIVAL OF A HIGH
PRES RIDGE/LIGHTER WINDS IN THE AFTERNOON. WINDS WILL THEN INCREASE
QUICKLY TUE NIGHT TO UPWARDS OF 30KT AS RIDGE SLIPS S AND THE NEXT
COLD FRONT DROPS S TOWARD NRN ONTARIO. THERE MAY BE A FEW GALE FORCE
GUSTS TO 35 KTS TUE NIGHT/WED...BUT MODERATING AIR MASS/DIMINISHING
OVERLAKE INSTABILITY SHOULD KEEP GALE GUSTS ON THE LIMITED SIDE.
BRISK WINDS GENERALLY IN THE 20-30KT RANGE WILL CONTINUE THRU THU AS
ARCTIC COLD FRONT PASSES. BEHIND THE FRONT...MUCH COLDER AIR WILL
RAISE POTENTIAL FOR HVY FREEZING SPRAY LATER THU INTO EARLY FRI.
ARRIVAL OF A HIGH PRES RIDGE WILL BRING DIMINISHING WINDS FOR
FRI/SAT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS
     EVENING TO 10 AM EST /9 AM CST/ TUESDAY FOR LSZ241>244-263-
     264.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...ROLFSON

NWS MQT Office Area Forecast Discussion

Courtesy National Weather Service