Area Forecast Discussion
Issued by NWS Marquette, MI

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922
FXUS63 KMQT 062043
AFDMQT

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

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST SAT FEB 6 2016

...LAKE EFFECT SNOW ADVISORY ISSUED FOR THE KEWEENAW PENINSULA
THROUGH MID AFTERNOON...

IR SATELITTE IMAGERY THIS MORNING IS SHOWING EXTENSIVE CLOUD COVER
ACROSS THE AREA WITH COLDER CLOUD TOPS SLIDING TOWARD THE THE
KEWEENAW PENINSULA. THIS IS ALONG AND AHEAD OF THE NEXT SHORTWAVE
SLIDING INTO THE UPPER GREAT LAKES REGION AS SHOWN BY ANALYZING WV
IMAGERY. RADAR IS SHOWING THE INITIAL WAVE OF PRECIPITATION SLIDING
OFF OVER THE EASTERN U.P. WITH A FEW RETURNS SHOWING UP OVER CENTRAL
LAKE SUPERIOR.

TODAY...A WEAK LOW PRESSURE SYSTEM CENTERED JUST TO THE SOUTHWEST OF
JAMES BAY THIS MORNING WILL SLOWLY SLIDE EASTWARD THROUGH THE
DAY...REACHING WESTERN QUEBEC BY LATE THIS AFTERNOON INTO THIS
EVENING. AS THIS HAPPENS...A BRIEF RIDGE OF HIGH PRESSURE WILL SLIDE
JUST NORTH OF THE CWA...WITH ANOTHER LOW PRESSURE SYSTEM DIRECTLY
BEHIND THE RIDGE...SLIDING INTO SASKATCHEWAN AND SOUTHERN MANITOBA.
THE FLOW AROUND THESE PRESSURE SYSTEMS ALONG WITH FLOW AROUND
ANOTHER HIGH PRESSURE CENTER TO THE SOUTH AND EAST OF THE AREA WILL
PUT THE CWA SORT OF IN THE SADDLE POINT OR COL...WHICH TENDS TO BE
FRONTOGENETIC IN THE LOW LEVELS. RIGHT NOW THE MOST LIKELY
CONVERGENT AREA ALONG THE FRONT WOULD BE ACROSS WESTERN LAKE
SUPERIOR...THE KEWEENAW PENINSULA AND EASTERN LAKE SUPERIOR. THAT IS
WHERE THE GENERAL FOCUS FOR INCREASED SNOW CHANCES WILL BE THROUGH
THE DAY. ALOFT...BROAD TROUGHING REMAINS IN PLACE ACROSS THE U.P.
AND MUCH OF THE EASTERN CONUS...WITH A COUPLE SHORTWAVES SLIDING
THROUGH THE AREA. ONE OF THOSE WILL BE SLIDING THROUGH THIS MORNING
HELPING TO INCREASE SNOW INTENSITY OVER THE KEWEENAW. THE MAIN AREA
OF CONCERN TODAY WILL BE ACROSS THE KEWEENAW PENINSULA...WHERE THE
AFOREMENTIONED CONVERGENT ZONE WILL BE...ALONG WITH WEST WINDS. THE
COMBINATION OF FORCING...UPSLOPE FLOW AND POTENTIAL LAKE ENHANCEMENT
WITH 850MB TEMPS PROGGED TO BE AROUND -12C TO -13C WILL HELP TO
PRODUCE MODERATE SNOWFALL OVER THE KEWEENAW PENINSULA. EQ HEIGHTS
ARE PROGGED TO BE AROUND 7KFT THROUGH THE LATE MORNING EARLY
AFTERNOON HOURS. HI-RES MODELS ARE POINTING AT A FAIRLY DOMINANT
BAND BETWEEN CALUMET AND DELAWARE THAT WOULD HELP PRODUCE SNOW
TOTALS IN ADVISORY RANGE AROUND 4 INCHES OR MORE IN A 12 HOUR
PERIOD. THE MAIN IMPACT FOR THE REMAINDER OF THE AREA WILL BE
INCREASED CLOUD COVER ALONG WITH SLIGHTLY WARMER TEMPERATURES TO THE
SOUTH OF THE FRONT.

TONIGHT...AFTER THE BRIEF RIDGE SLIDES EAST OF THE AREA THE NEXT LOW
PRESSURE SYSTEM WILL SLIDE FROM SOUTHERN MANITOBA AROUND 00Z/07 TO
NORTH CENTRAL MN BY 09Z/07. THIS WILL ALLOW THE FRONT DRAPED ACROSS
THE KEWEENAW PENINSULA TO SHIFT SLIGHTLY NORTHWARD AS A WARM
FRONT...PLACING MORE OF THE FOCUS OVER LAKE SUPERIOR. THIS WOULD
ALLOW ANY LAKE ENHANCEMENT TO DIMINISH PRETTY QUICKLY OVER THE
KEWEENAW AS WINDS WILL QUICKLY BECOME SOUTHERLY BETWEEN 00Z/07 AND
06Z/07 EFFECTIVELY DIMINISHING ANY MODERATE SNOW THAT MAY HAVE BEEN
FALLING THROUGH THE DAY. 850MB TEMPERATURES WILL ALSO BE WARMING TO
THE -6 TO -8 RANGE THROUGH THIS TIME PERIOD ALSO WORKING AGAINST ANY
LAKE ENHANCEMENT. THIS DOES NOT MEAN THAT THE CWA WILL BE DRY AS
THERE WILL BE PLENTY OF MOISTURE AROUND ALONG WITH WEAK ISENTROPIC
UPGLIDE ON WAA INTO THE AREA...HELPING TO PRODUCE VERY LIGHT SNOW
ACROSS THE CWA. MOST LOCATIONS WILL NOT SEE MUCH MORE THAN AN INCH
OR SO OUT OF THIS DURING THE NIGHT...HOWEVER...LOCATIONS OVER THE
KEWEENAW MAY END UP SEEING BETWEEN 1 AND 2 INCHES TONIGHT. OVERNIGHT
LOWS WILL BE KEPT A LITTLE WARMER WITH WAA AND INCREASED CLOUD COVER
OVER THE AREA AS WELL. GENERALLY EXPECTING LOWS TO BE IN THE MID 20S.

.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...KEC
LONG TERM...KC
AVIATION...KF
MARINE...KC



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