Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 062044
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
344 PM EST SAT FEB 6 2016

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 344 PM EST SAT FEB 6 2016

HAVE GONE AHEAD AND CANCELLED THE LAKE EFFECT SNOW ADVISORY ISSUED
FOR THE KEWEENAW PENINSULA A LITTLE EARLY. LATEST INDICATIONS FROM
SFC OBSERVATIONS SHOW LIMITED WIND CONVERGENCE...ALTHOUGH P59
CONTINUED TO SHOW N WINDS...THEY HAVE GONE CALM AT 19 AND 20Z. THIS
IS SUPPORTED BY SOCIAL MEDIA REPORTS AND WEBCAM IMAGES SHOWING
LITTLE ADDITIONAL SNOW.

MUCH OF OUR ATTENTION IN THE SHORT TERM WILL BE FOCUSED ON THE
PROGRESSION OF THE SFC LOW CURRENTLY SET UP ACROSS MUCH OF
SASKATCHEWAN...WITH IS BEING HELPED BY A 500MB WAVE SINKING ACROSS
SASKATCHEWAN AND E MT. BACK TO UPPER MI...A NEARLY STATIONARY FRONT
EXTENDING FROM SFC LOW WILL REMAIN ACROSS MAINLY THE S HALF OF LAKE
SUPERIOR THROUGH SUNDAY. THE MAIN RESULT OF THIS SYSTEM HAS BEEN
PLENTY OF MID TO HIGH CLOUDS ARE SPRAWLED ACROSS S CENTRAL
CANADA...AND N PLAINS...AND UPPER GREAT LAKES. CLOSER TO THE LOW
ITSELF...STRONG WINDS HAVE BEEN COMMON WITH SUSTAINED W WINDS AROUND
25-30KTS. AS THE SFC LOW SINKS ACROSS S MANITOBA LATE THIS
EVENING...AND TO W LAKE SUPERIOR BY THE END OF THE DAY SUNDAY...A
MAJORITY OF THE STRONGER WINDS WILL SPREAD WELL TO OUR S. STILL
EXPECT GUSTS NEARING 15-20KTS OVER THE W HALF LATE TONIGHT THROUGH
SUNDAY.

WARMER AIR WILL BE ABLE TO SURGE IN AHEAD OF THE LOW...WITH 850MB
TEMPS RISING FROM -4C W AND -11C E TO A CWA AVERAGED -3C BY DAYBREAK
ON 850MB WIND SW 35-45KTS. STILL LOOKS LIKE THE INITIAL ROUND OF
SNOW WILL BE EXITING CENTRAL-E UPPER MI BY EARLY MORNING...BEFORE
THE DRY SLOT SWEEPS IN. LOOK FOR SLIGHTLY COOLER AIR /850MB TEMPS
AROUND -5C/ AND W FLOW TO BRING IN THE LIKELY SNOW TO THE FAR W BY
THE END OF THE DAY. WAS INITIALLY CONCERNED THAT THERE COULD BE A
BRIEF MIX OF RAIN OR SNOW NEAR IWD AROUND 06Z BEFORE THE MOISTENING
OF THE LOWER LEVELS...AND THEN THROUGH THE DAY AS SFC TEMPS RISE
INTO THE MID TO UPPER 30S. GIVEN THE PROBABILITY...HAVE NOT INCLUDED
IT IN THE FCST...BUT WILL NEED TO KEEP AN EYE ON THE LATEST TRENDS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 PM EST SAT FEB 6 2016

THE MAIN WX STORY IN THE MEDIUM/EXTENDED RANGE WILL FOCUS ON THE
IMPACT OF AN AMPLIFYING UPR TROF OVER THE E HALF OF NAMERICA/
DEEPENING SFC LO PRES OVER THE CENTRAL GREAT LKS DOWNSTREAM OF A HI
AMPLITUDE RDG OVER THE W. AS H85 TEMPS TUMBLE AOB -20C BY TUE IN THE
STRONG NNW FLOW BTWN THIS LO AND CNDN HI PRES BLDG TOWARD THE NRN
PLAINS...EXPECT SOME PERSISTENT MDT LES AND BLSN TO IMPACT MAINLY
THE FAVORED SN BELTS ON MON INTO AT LEAST TUE AND PERHAPS WED. WELL
ABOVE NORMAL TEMPS ON SUN WL FALL BLO NORMAL THIS COMING WEEK WITH
THE INFLUX OF ARCTIC AIR.

SUN NGT/MON...AS A MID LVL CLOSED LO DROPS SSEWD FM NEAR WRN LK SUP
AT 00Z MON TO OVER LOWER MI BY MON AFTN...LLVL WINDS WL SHIFT FM THE
SW TO THE NNW W-E BY DAYBREAK ON MON EXCEPT PERHAPS OVER THE FAR ERN
CWA...WHERE THIS WSHFT MAY NOT OCCUR UNTIL CLOSER TO 18Z MON. WHILE
THERE MAY BE SOME LIGHT SN UNDER INCRSGLY DEEP MSTR ASSOCIATED WITH
THE FALLING HGTS AHEAD OF THE WSHFT...HEAVIER SN SHOWERS WL DVLP
MAINLY IN THE FAVORED SN BELTS NEAR LK SUP FOLLOWING THE WSHFT AS
THE CYC NNW FLOW DRAWS COLDER AIR INTO THE AREA AND DROPS H85 TEMPS
TO ARND -15C OVER THE FAR W LATE IN THE DAY. COMBINATION OF UPSLOPE
AND LK ENHANCEMENT WL LIKELY RESULT IN THE NEED FOR SOME ADVYS...
ESPECIALLY OVER THE W WHERE THE WSHFT/COLDER AIR WL ARRIVE EARLIER.
WL MAINTAIN HIER CATEGORICAL POPS AND SOME BLSN IN EXPOSED LOCATIONS
NEAR LK SUP AS H925 WINDS INCRS UP TO 30 KTS.

MON NGT THRU TUE NGT...A PERSISTENT CYC NNW FLOW IS PROGGED TO DRAW
H85 TEMPS AS LO AS -25C INTO THE UPR LKS ON TUE NGT. WHILE THE
MODELS ALL SHOW DEEP MSTR/QVECTOR CNVGC THAT WL FAVOR SOME MDT TO
PERHAPS HEAVY LES LINGERING THRU AT LEAST 12Z TUE...THE MEDIUM RANGE
GUIDANCE VARIES ON HOW QUICKLY THE UPR TROF AXIS AND THUS THE DEEPER
MSTR/SOME DEEP LYR QVECTOR CNVGC/CONTINUED LK ENHANCEMENT WL EXIT W-
E. CONSIDERING THE HI AMPLITUDE PATTERN THAT WL DOMINATE...SUSPECT
THE SLOWER GUIDANCE IS ON THE RIGHT TRACK. ON THE OTHER HAND...MODEL
TRENDS APPEAR TO SUPPORT A QUICKER EXIT OF THE DEEP MSTR...SO WL
BEGIN TO SHOW A DIMINISHING TREND TO THE SN SHOWER INTENSITY OVER
THE W ON TUE/TUE NGT WHILE HOLDING ON TO THE HIER CATEGORICAL POPS
GIVEN LLVL FACTORS THAT WL SUPPORT WDSPRD ALBEIT LIGHTER LES.

WED INTO THU...WHILE A PERSISTENT CYC N SLOWLY WEAKENING/BACKING TO
NW FLOW AS SFC HI PRES BECOMES ORIENTED FM NEAR LK WINNIPEG INTO WRN
WI WL BRING PURE LES DURING THIS PERIOD IN THE SHIFTING FAVORED SN
BELTS WITH H85 TEMPS STILL BLO -20C...MID LVL DRYING AND LARGER
SCALE SUBSIDENCE UNDER DNVA/DEEP LYR QVECTOR DVGC THAT IS FCST TO
FOLLOW THE EXIT OF THE UPR TROF AXIS TO THE E WL LIMIT THE INTENSITY
OF THE SN SHOWERS. BUT STILL MAINTAINED HIER POPS ABOVE THE
CONSENSUS FCST GIVEN THE FAVORABLE PARAMETERS FOR THE SHALLOWER LES.
IF THERE IS SOME CLRG NEAR THE WI BORDER/SCENTRAL ON WED NGT...LO
TEMPS THERE COULD FALL WELL BLO ZERO.

FRI/SAT...THE LONGER RANGE GUIDANCE HINTS ANOTHER SHRTWV EMBEDDED IN
THE NW FLOW BTWN THE DEEP ERN TROF/WRN RDG WL PASS NEAR THE UPR
GREAT LKS ON FRI. WHILE ABSENCE OF ANY MSTR INFLOW WL LIMIT THE CHC
FOR ANY LARGER SCALE PCPN...INFLUX OF COLDER AIR/H85 TEMPS FCST TO
AS LO AS -25 TO -30C WL BRING MORE LES AND WELL BLO NORMAL TEMPS.
BUMPED UP POPS ABOVE THE CONSENSUS FCST OVER THE EXPECTED FAVORED
SN BELTS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 109 PM EST SAT FEB 6 2016

VFR TO MVFR CEILINGS AND MAINLY VFR VIS WILL BE THE RULE AT IWD AND
SAW...BECOMING MVFR THIS EVENING. FARTHER N AT CMX...LAKE EFFECT
SNOW SHOWERS ARE STARTING TO SHIFT N OF THE SITE. STILL ANTICIPATE
MVFR CEILINGS TO REMAIN THERE THROUGH AT LEAST 18Z SUNDAY. NEARING
LOW PRESSURE FROM S CENTRAL CANADA WILL PUSH OVER FAR NW MN/FAR S
MANITOBA BY 06Z SUNDAY...ALLOWING SNOW TO SPREAD W-E ACROSS THE TAF
SITES. THE LOW PRESSURE SYSTEM WILL MOVE OVER NE MN/W LAKE SUPERIOR
BY 18Z SUNDAY..PUSHING MUCH OF THE INITIAL AREA OF SNOW NE. STEADIER
SNOW IS EXPECTED TO SWING IN AFTER 18Z SUNDAY.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 342 PM EST SAT FEB 6 2016

EXPECT SSE WINDS UP TO 25 KTS TONIGHT TO VEER TO THE SW ON
SUN AS A LO PRES APPROACHES THE UPPER LAKES. AFTER THIS LO SLIDES
INTO THE CENTRAL GREAT LKS BY MON...WINDS WILL SHIFT TO THE N AND
INCREASE TO 30-35KTS AS THE PRES GRADIENT TIGHTENS BETWEEN THIS LO
AND HI PRES BUILDING INTO SCENTRAL CANADA. DEPENDING ON HOW QUICKLY
THE LO SHIFTS TO THE E...THE MARGINAL N GALES MAY PERSIST INTO
WED...ESPECIALLY OVER THE E HALF OF THE LAKE. WITH THE INFLUX OF
COLDER AIR AND STRONG WINDS...HEAVY FREEZING SPRAY WILL IMPACT THE
AREA FROM MON NIGHT INTO WED AS WELL. THE WINDS AND HEAVY FREEZING
SPRAY WILL DIMINISH LATER ON WED/THU AS THE HI PRES EDGES CLOSER TO
THE WESTERN LAKES. THERE MAY BE ANOTHER ROUND OF HEAVY FREEZING
SPRAY ON FRI FOLLOWING ANOTHER COLD FRONTAL PASSAGE LATE IN THE WEEK.
&&

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

$$

SHORT TERM...KF
LONG TERM...KC
AVIATION...KF
MARINE...KC


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