FXUS63 KMQT 050934
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
434 AM EST SUN FEB 5 2012

.SYNOPSIS...

00Z RAOBS SHOW DECAYING UPR LOW OVR KS/MO WHILE LARGER SCALE RIDGE
IS LOCATED FM WEST CONUS INTO WESTERN CANADA. PRIMARY TROUGHING IS
ORIENTED FM NORTHERN CANADA INTO QUEBEC AND NEW BRUNSWICK. COLDEST
AIR BY FAR IS LOCATED OVR FAR NORTHERN SECTIONS OF CANADA IN VCNTY
OF POLAR VORTEX. OTHERWISE...MOST OF CANADA AND THE CONUS FOR THAT
MATTER IS AWASH IN CONTINUAL FLOW OF MILD PACIFIC AIR. THIS WEEK
RIDGE IS EXPECTED TO BECOME MORE MERIDIONAL FM WESTERN CONUS INTO
ALASKA. RESULT IS EASTERN CANADA TROUGH TO SETTLE TOWARD GREAT LAKES
AND NORTHEAST CONUS. FIRST PUSH OF COOLER AIR ARRIVES ACROSS UPR
LAKES LATE MONDAY INTO TUESDAY. ANOTHER SHOT OF MUCH COLDER AIR IS
POSSIBLE LATE THIS WEEK INTO FIRST PART OF NEXT WEEKEND AS PORTION
OF POLAR VORTEX TRIES TO DISLODGE AND COME INTO THE CONUS. PATTERN
DOES NOT SUGGEST MUCH IN WAY OF OPPORTUNITY FOR LARGE SCALE WINTER
SYSTEMS. MAIN SNOWFALL THROUGH PERIOD WILL COME VIA LK EFFECT.
&&

.SHORT TERM /TODAY THROUGH MONDAY NIGHT/...

IN THE NEAR TERM...SFC RIDGE OVR PLAINS BEGINS TO EXPAND INTO UPR
LAKES. RUC13 HAS MUCH BETTER HANDLE ON CURRENT STRATUS THAN 00Z
NAM. PER RUC13 OUTPUT AND RAOBS...MOISTURE ADVECTION IN THE CLOUD
BEARING LAYER IS NEUTRAL SO EXPECT STRATUS BASED AROUND 925MB TO
PERSIST OVR CNTRL AND EASTERN CWA. TEMPS WILL REMAIN IN THE UPR 20S
TO LOWER 30S...EXCEPT STAYING IN THE TEENS OVR FAR WEST.

TODAY AND TONIGHT...EXPECT STRATUS TO CLEAR FM WEST TO EAST THIS
MORNING AS 925MB WINDS TURN WESTERLY ALLOWING LOWER 925MB DWPNTS TO
ADVECT INTO UPR LAKES. ONCE LOW CLOUDS DEPART...MIXING HEIGHTS BUILD
BENEATH MOSTLY SUNNY SKIES /THOUGH MAY SEE SCT-BKN MID CLOUDS INTO
EARLY AFTN NCNTRL AND EAST BASED ON CURRENT TRAJECTORIES OF CLOUDS
DROPPING ACROSS ONTARIO/. MODEL PROFILES FM BUFKIT INDICATE MIXING
ONLY TO 925MB BUT GIVEN EXPECTED INSOLATION...AND SEEING THAT LOW-
LEVELS MIXED AOA 900MB ON SATURDAY PER KGRB 00Z SOUNDING...WILL OPT
FOR MORE MIXING AND HIGHER TEMPS. BLEND OF 900MB-850MB MIXING HEIGHT
SUPPORTS HIGHS WELL INTO THE 40S AND MAYBE EVEN NEAR 50 DEGREES...
ESPECIALLY IN DOWNSLOPE AREAS OF CNTRL CWA /BARAGA TO MARQUETTE AND
SOUTH TO ESCANABA AND MENOMINEE/. BASED ON HOW WARM TEMPS WERE
YDY...MAY COME CLOSE TO THE RECORD HIGH OF 50 DEGREES FOR WFO
MARQUETTE /2005/. THE WARM DAY WILL TRANSLATE TO WELL ABOVE NORMAL
TEMPS FOR TONIGHT. WARMING WILL BE MOST PRONOUNCED NEAR LK SUPERIOR
SHORE WITH WEST WINDS STIRRING ALL NIGHT AHEAD OF COLD FRONT
APPROACHING FM THE NORTH. BASED ON UPSTREAM READINGS THIS MORNING
AHEAD OF COLD FRONT...WINDS MAY STILL BECOME LIGHT IN THE INTERIOR SO
KEPT LOWS AROUND 20F INLAND WEST.

MONDAY...COLD FRONT REACHES KEWEENAW BTWN 15-18Z...THEN SWINGS
THROUGH FM NORTH TO SOUTH THROUGH THE DAY OVR REST OF CWA. RETAINED
FALLING TEMP IDEA FM PREVIOUS SHIFT...ESPECIALLY OVER THE NORTH HALF
OF THE CWA IN THE AFTN. WEST FLOW AND H9 TEMPS NEAR 0C AHEAD OF FRONT
SHOULD ALLOW TEMPS OVR FAR SCNTRL TO CLIMB INTO THE LOW 40S AT KMNM...
BEFORE FALLING OFF INTO THE LOWER 30S LATE. TEMPS WILL FALL FM THE
LOWER 30S INTO THE LOWER 20S BY SUNSET OVR REST OF THE CWA. SEEMS
THAT PCPN CHANCES WILL BE FAIRLY LIMITED UNTIL MONDAY NIGHT. FCST
SOUNDINGS FM NAM/GFS SUGGEST INCREASING STRATOCU CLOUDS MORE THAN
ANYTHING ELSE. MOIST LAYER FCST TO REACH -10C LATE AFTN INTO EARLY
EVENING SO COULD SEE SNOW GRAINS OR FLURRIES LATE IN THE DAY OVR
HIGHER TERRAIN OF NW CWA.

MONDAY NIGHT...COOLING CONTINUES AT 925-850MB WITH FCST SOUNDINGS
INDICATING MOISTURE THROUGH AROUND 5KFT BY 06Z-12Z IN A WEAKLY
CYCLONIC NORTHERLY FLOW REGIME. UNIDIRECTIONAL FLOW THROUGH
850MB/5KFT WITH WIND SPEEDS LESS THAN 20 KTS SHOULD HELP LK EFFECT
ORGANIZE LATE EVENING INTO OVERNIGHT HOURS. DESPITE SUBSIDENCE/DRYING
ABOVE INVERSION AT H85...MAJORITY OF LAKE CONVECTIVE LAYER IS WITHIN
MOST IDEAL SNOW DENDRITIC GROWTH ZONE WITH TEMPS -12C TO -18C. ECMWF
IS ON THE WARM END WHILE CANADIAN INDICATES H85 TEMPS DOWN NEAR -20C
BY LATE MONDAY NIGHT. CERTAINLY HAVE SEEN MORE IMPRESSIVE LK EFFECT
SETUP BUT DOES SEEM THAT NRLY WINDS...LOW-LEVEL CONVERGENCE...AND
FAVORABLE MOISTURE WITHIN THE DGZ JUSTIFIES INCREASING POPS OVR FAR
WEST AND ALSO OVR MUCH OF MARQUETTE AND ALGER COUNTIES. A FEW INCHES
OF SNOW IS NOT OUT OF QUESTION MONDAY NIGHT AIDED BY HIGH SLR/S AND
INCREASING FLUFFINESS TO THE SNOW. EXPECT MINS INTO THE SINGLE
DIGITS OVR THE INTERIOR WEST WITH READINGS IN THE TEENS FOR OTHER
AREAS.

.LONG TERM /12Z TUE THRU SAT/...

TUE...ALTHOUGH A SHRTWV WL BE PUSHING THRU THE UPR GRT LKS ON TUE
MRNG FOLLOWING THE SHARP COLD FROPA MON NGT...LATEST MODELS RUNS
HAVE CONTINUED TREND TOWARD RISING HGTS SHARPLY IN THE AFTN WITH
VIGOROUS DNVA/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE WAKE OF THE
SHRTWV PASSAGE RESULTING IN SHARP ACYC FLOW BY 00Z WED. ONGOING LES
OVER MAINLY THE N WIND SN BELTS IN THE MRNG WITH H85 TEMPS FCST BTWN
-14C BY THE ECMWF TO AS LO AS -20C BY THE CNDN MODEL WL SUPPORT
LIKELY POPS IN THE FAVORED SN BELTS WITH INVRN HGTS ARND 4K FT AGL
AT 12Z. BUT THE SHSN WL TEND TO DIMINISH STEADILY THRU THE DAY
ESPECIALLY OVER THE W AS H85 TEMPS ARE FCST TO RISE UP AS HI AS -10C
BY THE ECMWF BY 00Z WED. THE 00Z GFS INDICATES THE STRONG SUBSIDENCE
WL CAUSE THE INVRN BASE TO SINK TO 2K FT AGL BY 00Z WED...ENDING ANY
SGNFT SHSN BY LATE IN THE DAY AS PWAT SINKS BLO 0.10 INCH.

TUE NGT...UNDER RISING HGTS...SHRTWV RDG IS PROGGED TO BLD SLOWLY
THRU THE UPR GRT LKS. WITH PWAT FCST AS LO AS 0.10 INCH/MOCLR SKIES
AND LGT WINDS...EXPECT TEMPS OVER THE INTERIOR SCNTRL TO SINK AOB
THE LO END OF GUIDANCE. READINGS NEAR LK SUP WL BE BUOYED A BIT BY A
STRONGER W WIND TO THE N OF THE SFC RDG AXIS ORIENTED THRU NRN WI
INTO NRN LWR MI.

EXTENDED...HI PRES RDG WL DROP INTO THE OH VALLEY ON WED WITH A DRY
WLY FLOW DOMINATING AND TEMPS A BIT ABV NORMAL. NEXT SHRTWV WL
IMPACT THE UPR LKS ON THU. THE 00Z GFS/CNDN MODELS ARE IN FAIRLY
GOOD AGREEMENT SHOWING A STRONGER DISTURBANCE/SFC LO MOVING THRU THE
UPR LKS. WHILE THE 12Z ECMWF RUN SHOWED A SIMILAR SCENARIO...THE 00Z
RUN HAS BACKED OFF ON THE INTENSITY OF THIS DISTURBANCE...CONTINUING
A TREND OF MODEL INCONSISTENCIES ON THE HANDLING OF THIS SHRTWV. SO
WENT NO HIER THAN CHC POPS FOR SN ON THU. WITH THE ARRIVAL OF COLDER
AIR IN THE WAKE OF THE SHRTWV PASSAGE /H85 TEMPS AS LO AS -26C PER
THE 00Z GFS BUT ONLY -20C PER THE ECMWF/... EXPECT LES MAINLY IN THE
NW WIND SN BELTS INTO FRI NGT. THE ARRIVAL OF HI PRES ON SAT WL
CAUSE THE LES TO DIMINISH. EXPECT TEMPS TO RUN AOB NORMAL THU NGT
INTO SAT.
&&

.AVIATION /FOR THE 06Z TAF ISSUANCE/...

MVFR CLOUDS AT ALL THE TAF SITES SHOULD LIFT AND DECREASE BY LATE
MORNING AS A HIGH PRESSURE RIDGE MOVES ACROSS THE AREA AND NRLY
WINDS BACK TO THE WEST. SCT-BKN MID CLOUDS THEN SLIDE THROUGH INTO
MID AFTN. CONDITIONS WILL BE VFR AFTER THE LOWER CLOUDS CLEAR THIS
MORNING.
&&

.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...

NORTHERLY WINDS TURN WEST AND INCREASE TO 30 KTS THIS AFTERNOON AND
EVENING AHEAD OF COLD FRONT DROPPING SOUTH ACROSS ONTARIO. MAY SEE
GALE GUSTS TO 35 KTS DUE TO COASTAL CONVERGENCE ALONG TIP OF
KEWEENAW PENINSULA. WINDS BECOME NORTHERLY ON MONDAY AFTERNOON IN
WAKE OF COLD FRONT. GALE GUSTS TO 35 KTS POSSIBLE MONDAY EVENING
OVER NORTH AND EAST...BUT THEN WINDS DIMINISH TO LESS THAN 25 KTS
LATER MONDAY NIGHT AS HIGH PRESSURE RIDGE QUICKLY BUILDS INTO UPR
LAKES REGION. A RISK OF HEAVY FREEZING SPRAY MONDAY NIGHT OVR
NORTHERN SECTIONS AS TEMPS DROP TOWARD ZERO.

THE ARRIVAL OF THE HI PRES RDG WILL CAUSE DIMINISING WINDS ON
TUE/TUE NIGHT...BUT A STRONGER WSW FLOW UP TO 25-30 KTS WILL DEVELOP
ON WED AS THIS RDG SINKS TO THE S. THE HIGHEST WINDS ARE MOST LIKELY
BETWEEN THE KEWEENAW AND ISLE ROYALE WHERE TERRAIN INFLUENCES TEND
TO ENHANCE THIS FLOW. FOLLOWING THE PASSAGE OF A LO PRES ON THU...
PLAN ON A STRONGER NNW FLOW OF COLDER AIR. THERE ARE MODEL
DIFFERENCES ON THE FORECAST INTENSITY OF THIS LO...AND GALES WOULD
NOT BE OUT OF THE QUESTION IF THE DEEPER SCENARIO VERIFIES. WITH THE
POTENTIAL ARRIVAL OF MUCH COLDER AIR...HEAVY FREEZING SPRAY MAY
IMPACT PORTIONS OF THE LAKE ON THU...ESPECIALLY THE NCENTRAL.
&&

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

$$

SYNOPSIS...JLA
SHORT TERM...JLA
LONG TERM...KC
AVIATION...JLA
MARINE...JLA/KC



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