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000
FXUS63 KMQT 301958
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
258 PM EST SAT NOV 30 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EST SAT NOV 30 2013

LARGE AND STRONG 30.8IN/1044MB/ SFC HIGH IS SET UP OVER THE NEW
ENGLAND STATES...WITH ANOTHER AREA OF HIGH PRESSURE OVER MT/W
ND/SASKATCHEWAN. IN BETWEEN...AN ELONGATED AREA OF HIGH PRESSURE
STRETCHED FROM MANITOBA THROUGH ND AND W MN...THROUGH SD. TAKING A
LOOK ALOFT THE WV IMAGERY HELPS PICK OUT THE NEXT SHORTWAVE NEARING
FROM S MANITOBA.

AFTER VIEWING THE 00Z/30 SOUNDING FROM GRB IT LOOKS LIKE A LOT OF
DRY AIR WILL NEED TO BE MOISTENED UP BEFORE WE CAN GET ANY
SIGNIFICANT SNOWFALL. VIS AT CMX HAS BEEN ABLE TO FALL TO AROUND 3SM
OFF AND ON THIS MORNING. HOWEVER...AREA WEB CAMERAS ARE NOT
INDICATING THAT MUCH OF A REDUCTION IN VIS AS A WHOLE. CONTINUE TO
MONITOR THE CONVERGENT S WINDS OFF LAKE MI FOR ENHANCED SNOW. WITH
SFC TEMPS NEAR FREEZING AND PAVEMENT TEMPS OF 29-31F...DO NOT EXPECT
SIGNIFICANT TRAVEL PROBLEMS. IN FACT ISQ IS STILL UNDER A 5KFT
CEILING. WATCHING INITIAL BAND OF SNOW STRETCHING FROM NEAR IWD
THROUGH THE KEWEENAW PENINSULA AND OVER S CENTRAL LAKE SUPERIOR
SLOWLY PUSH E THIS MORNING. EXPECT SOME BETTER ENHANCEMENT OVER THE
KEWEENAW STARTING AROUND 18Z...AS THE SFC TROUGH PUSHES THROUGH.

THE SFC LOW SHOULD BE EXITING E UPPER MI BY 00Z SUNDAY. KEPT THE
MENTION IN THE FCST WITH CLOUDS LOWERING TO A NEARLY 1.5-2KFT CLOUD
DECK OVER THE N HALF OF UPPER MI OVERNIGHT UNDER ONSHORE FLOW OFF.
THE TIMING LOOKS TO BE SET UP FOR MAINLY 01-07Z SUNDAY OVER N
CENTRAL AREAS. THE DGZ WILL REMAIN WAY UP BETWEEN 700 AND
600MB...VOID OF MOISTURE OVERNIGHT. FZDZ...DZ /MAINLY OVER LAKE
SUPERIOR AND NEAR THE SHORELINE/...OR LIGHT SNOW SHOWERS WILL BE
POSSIBLE. ACCUMULATIONS WILL BE LIGHT...WITH TOTAL QPF OVERNIGHT
TOPPING OUT LESS THAN 0.05IN MOST PLACES.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 PM EST SAT NOV 30 2013

WITH SUBTLE FEATURES AND RELATIVELY LIGHT PRECIP POSSIBLE MON/MON
NIGHT...AND A VERY UNCERTAIN TUE-THU PERIOD DUE TO MODEL VARIABILITY
WITH A LOW MOVING SOMEWHERE NEAR THE CWA...THE HIGHEST CONFIDENCE IN
THE LONG TERM PORTION OF THE FORECAST IS ACTUALLY FRI AND NEXT SAT
AS MUCH COLDER AIR MOVES OVER THE REGION WITH GENERALLY W WINDS
LEADING TO LES.

MON AND MON NIGHT WILL NOT HAVE ANY SIGNIFICANT FEATURES MOVING
THROUGH...BUT WITH 850MB TEMPS AROUND -10C AND GENERALLY E LOW LEVEL
WINDS...COULD SEE SOME LIGHT LAKE EFFECT/UPSLOPE PRECIP. LOOKING AT
NAM AND GFS MODEL SOUNDINGS FOR THE PERIOD...THINK THAT LOW LEVEL
MOISTURE WILL EXTEND UPWARD INTO COLD ENOUGH TEMPS TO KEEP PRECIP AS
ALL SNOW. THUS...MENTIONS OF DRIZZLE AND FREEZING DRIZZLE WERE
REMOVED FROM THE FORECAST.

UNCERTAINTY IS GREATLY INCREASED TUE THROUGH MUCH OF THU AS MODEL
EXHIBIT UNUSUALLY HIGH AMOUNTS OF DISAGREEMENT AND RUN TO RUN
DISCONTINUITY FOR THIS FAR OUT. THE SYSTEM...AS IT STANDS NOW...IS
OVER THE SRN BORDER OF MAINLAND AK AND CANADA IN AN AREA WITH A
LOWER CONCENTRATION OF UPPER AIR OBSERVATIONS. THINK THAT MOST OF
THE DISAGREEMENT COMES NOT SO MUCH FROM DIFFERENT INITIALIZATIONS
DUE TO FEWER OBSERVATIONS...BUT RATHER FROM MODELS HANDLING THE
UPPER ENERGY OF THE SYSTEM AFTER ITO MOVES TOWARD THE PACIFIC NW
CONUS ON MON. WHILE THE 00Z/30 ECMWF KEEPS THE UPPER ENERGY BUNDLED
MORE IN A SINGLE DEEP UPPER TROUGH /MATCHED BY THE LAST 2 RUNS OVER
12 HOURS/...THE LAST 3 RUNS /OVER 12 HOURS/ OF THE GFS EJECTS SOME
OF THE ENERGY OUT AHEAD OF THE UPPER TROUGH...RESULTING IN MUCH
FASTER ARRIVAL OF A LOW PRESSURE SYSTEM THAN FROM THE ECMWF. WITH
BOTH OF THE MAIN MODELS AT THIS RANGE SHOWING DECENT RUN TO RUN
CONTINUITY /OVER THE LAST 12 HOURS ANYWAY...BEFORE THAT IT WAS VERY
POOR/...HAD TO CHOOSE ONE OR THE OTHER...HENCE THE LOW CONFIDENCE.
FOR SPECIFICS ON EACH...THE 12Z/30 GFS BRINGS A CLOSED...STACKED LOW
TO NR WI BY 00Z WED AND MOVES IT TO JUST NE OF LAKE SUPERIOR BY 18Z
WED...WITH TEMP PROFILES SUPPORTIVE OF RAIN OVER SCENTRAL AND SERN
UPPER MI. THE 00Z/30 ECMWF BEING SLOWER AND FARTHER NW HAS A SFC LOW
OVER NW MN BY 00Z THU THAT MOVES NNE TO NEAR THE CENTRAL
MANITOBA/ONTARIO BORDER BY 18Z THU. THERMAL PROFILES FROM THE ECMWF
WOULD SUPPORT PREDOMINANTLY RAIN /AND POSSIBLY FREEZING RAIN/ OVER
THE CWA WITH THE EVENT...AND BOTH MODELS SHOW SIGNIFICANT QPF ON THE
E/NE TO NW FLANKS OF THE SFC LOW AND ASSOCIATED NEGATIVELY TILTED
UPPER TROUGH. TO COMPARE ANOTHER MODEL...THE 12Z/30 GLOBAL GEM
BRINGS A WEAKER SFC LOW TO FAR WRN LAKE SUPERIOR AT 06Z THU...THEN
TO NE OF LAKE SUPERIOR BY 18Z FRI...WHICH IS SIMILAR TO THE TRACK OF
THE GFS AND THE TIMING OF THE ECMWF. THINK THAT THE GFS MAY BE TOO
FAST AND THE ECMWF TOO SLOW...SO WILL ESSENTIALLY TRY TO REPRESENT A
CONSENSUS OF THESE TWO MODELS IN THE FORECAST...BUT THAT WILL NOT BE
EASY SINCE THEY ARE SO DIFFERENT ON TIMING.

FOR FRI AND SAT...CONFIDENCE ACTUALLY INCREASES SOME AS MODELS AGREE
ON MUCH COLDER AIR ARRIVING FRI INTO SAT. THE LATEST GFS RUN
INTRODUCED SOME DISCREPANCIES IN THE WIND FIELDS AS IT TIES WIND
FIELDS TO A TROUGH FROM A SFC LOW OFF THE ERN SEABOARD INSTEAD OF
THE DEPARTING LOW...RESULTING IN NLY WINDS ON FRI INSTEAD OF THE
PREVIOUS INDICATED WLY WINDS THAT AGREED BETTER WITH THE ECMWF.
HOWEVER...BY FRI NIGHT AND INTO SAT...MODELS AGREE WELL ON GENERALLY
WLY LOW LEVEL WINDS OVER LAKE SUPERIOR. THE ECMWF BRINGS THE COLDER
AIR IN FASTER THAN THE GFS SINCE IT HAS A DEEP UPPER LOW WITH THE
EARLIER SYSTEM INSTEAD OF A WEAKER OPEN WAVE ALOFT LIKE THE GFS. THE
ECMWF SHOWS -20C 850MB TEMPS OVER FAR WRN LAKE SUPERIOR BY 00Z
FRI...WITH ANOTHER TEMP DROP OF 2-4C BY FRI MORNING. THESE COLDER
THE GFS MOVES THE -20C 850MB AIR OVER WRN LAKE SUPERIOR BY 00Z SAT.
THESE COLDER TEMPS STICK AROUND THROUGH SAT. OF COURSE...THESE TEMPS
WOULD PROVIDE SUBSTANTIAL LAKE INDUCED INSTABILITY SUPPORTIVE OF
LES...BUT WITH THE DGZ BEING SO LOW IN THOSE TEMPS THE SNOW TO
LIQUID RATIO WOULD NOT BE AS HIGH AS IT COULD BE. WITH THE W WINDS
/AND POSSIBLE WSW WINDS/ THE KEWEENAW AND POSSIBLY NERN U.P. WOULD
BE FAVORED FOR THE BEST SNOWFALL CHANCES. WITH THE LOWER SNOW TO
LIQUID RATIOS...HAVE A HARD TIME SEEING WIDESPREAD WARNING
AMOUNTS...BUT AN EXTENDED ADVISORY MAY BE NEEDED...BUT OF COURSE IT
IS VERY FAR OUT TO GET TOO SPECIFIC.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1252 PM EST SAT NOV 30 2013

AS COOLER AIR DROPS SOUTHEAST ACROSS LAKE SUPERIOR THIS AFTERNOON
BEHIND A LOW PRESSURE SYSTEM THE POTENTIAL FOR LAKE EFFECT SNOW
INCREASES AT ALL THREE TAF SITES THROUGH THIS EVENING. CURRENT
EXPECTATION IS THAT THE SNOW WILL BE LIMITED IN INTENSITY...BUT
LOWER CEILINGS UPSTREAM WOULD SUPPORT CEILINGS FALLING TO MUST FILE
ALTERNATE VALUES AND POTENTIALLY EVEN IFR AT KCMX TOWARDS LATE
EVENING AND EARLY OVERNIGHT HOURS. A HIGH PRESSURE RIDGE MOVING
OVER LAKE SUPERIOR OVERNIGHT WILL VEER THE WINDS TO THE
NORTH-NORTHEAST AND LEAD TO LESS FAVORABLE WIND DIRECTIONS FOR
KCMX/KIWD AND HAVE TRIED TO SHOW A DIMINISHING TREND IN SNOW SHOWERS
AND ALSO RAISED CEILINGS SOMEWHAT. CONFIDENCE IN SNOW SHOWER
LOCATION/STRENGTH GROWS LATE TONIGHT INTO SUNDAY...DUE TO WINDS
BECOMING LIGHT AND VARIABLE THROUGH THE DAY.

ONE FINAL NOTE...WITH THE AMOUNT OF ICE CRYSTALS IN THE CLOUD AWAY
FROM THE SNOW SHOWERS...THERE IS THE POTENTIAL FOR SOME VERY LIGHT
FREEZING DRIZZLE AT ALL THREE SITES. THINK THE BEST OPPORTUNITY
WOULD BE AT KIWD...BUT OPTED TO LEAVE OUT DUE TO THE VERY PATCHY
NATURE.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 346 AM EST SAT NOV 30 2013

A FEW SOUTHERLY GALE FORCE GUSTS TO 35KTS OVER EASTERN LAKE SUPERIOR
WILL QUICKLY DIMINISH THIS MORNING AS LOW PRESSURE OVER WESTERN LAKE
SUPERIOR PUSHES EAST ACROSS THE LAKE AND TO FAR SOUTHEASTERN ONTARIO
AND THE LOWER GREAT LAKES SUNDAY. EXPECT HIGH PRESSURE ACROSS
NORTHERN MANITOBA TODAY TO SWEEP OVER MANITOBA SUNDAY THROUGH SUNDAY
NIGHT...BUILDING A RIDGE ACROSS LAKE SUPERIOR LATE TONIGHT THROUGH
SUNDAY. EXPECT LOW PRESSURE STRETCHED ACROSS THE U.S. AND CANADIAN
BORDER FROM WASHINGTON THROUGH MONTANA SUNDAY NIGHT TO SINK ACROSS
THE PLAINS STATES MONDAY AND TUESDAY. CLOSER TO HOME...AN ADDITIONAL
AREA OF HIGH PRESSURE PUSHING ACROSS ONTARIO WILL STRENGTHEN THE
RIDGE ACROSS LAKE SUPERIOR TUESDAY NIGHT INTO EARLY WEDNESDAY. THE
LOW OVER THE PLAINS STATES SHOULD SHIFT NORTHWARD TO MINNESOTA AND
WISCONSIN BY WEDNESDAY EVENING. TAKING A LOOK FARTHER OUT...ANOTHER
PERIOD OF GALES OR NEAR GALES WILL BE POSSIBLE THURSDAY NIGHT
THROUGH FRIDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KF
LONG TERM...TITUS
AVIATION...SRF
MARINE...KF