Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 041740
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1240 PM EST THU FEB 4 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EST THU FEB 4 2016

GENERALLY LIGHT LES CONTINUES TO SLOWLY DIMINISH EARLY THIS MORNING
AS A SFC RIDGE IS PUSHING IN FROM THE W...AND IS ALREADY OVER WRN
LAKE SUPERIOR. MEANWHILE...A SHORTWAVE/SFC TROUGH IS OVER NWRN
MN...WITH VERY LIGHT SNOW OVER THE DLH CWA RIGHT NOW.

SHOULD SEE THE VERY LIGHT SNOW TO THE W MOVE THROUGH UPPER MI TODAY
INTO TONIGHT...ALTHOUGH SOME AREAS MAY NOT SEE ANY PRECIP. HAVE A
HALF INCH OR LESS FROM THE SYNOPTIC SNOW. THE SHORTWAVE LOOKS TO
LEAD TO A COMPACT SFC LOW THAT DEVELOPS OVER WRN LAKE SUPERIOR THIS
AFTERNOON AND MOVES TO FAR ERN LAKE SUPERIOR BY 12Z FRI. SHOULD SEE
NW WIND LAKE EFFECT DEVELOP ON THE BACK SIDE OF THE LOW...AND EVEN
SOME HEAVIER SNOWFALL POSSIBLE IN BANDS RESULTING FROM CONVERGENCE
AROUND THE LOW.

HAVE SNOWFALL AMOUNTS OF LESS THAN AN INCH THROUGH TONIGHT
INLAND...WITH 2-3 INCHES EXPECTED IN SOME OF THE NW WIND SNOWBELTS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 535 AM EST THU FEB 4 2016

A MEAN TROF IS CURRENTLY IN THE PROCESS OF BECOMING ESTABLISHED OVER
THE E HALF OF N AMERICA DONWSTREAM OF A MEAN RIDGE POSITION
BASICALLY ALONG THE W COAST OF N AMERICA. ONE SHORTWAVE TROF WILL
SHIFT ACROSS THE MISSISSIPPI VALLEY/GREAT LAKES EARLY IN THE
WEEKEND. RAPID BUILDING OF POSITIVE HEIGHT ANOMALIES IN THE WRN
RIDGE LATE IN THE WEEKEND WILL THEN LEAD TO SHARP AMPLIFICATION OF
THE TROF OVER THE ERN CONUS EARLY NEXT WEEK. THIS WILL SPELL THE
ONSET OF A COLD/BLO NORMAL TEMP REGIME FOR THE UPPER GREAT LAKES.
THERE ARE STILL SOME INDICATIONS OF A BITTERLY COLD AIR MASS DIVING
INTO THE UPPER LAKES IN THE FEB 11 TO FEB 13 TIME FRAME. HOWEVER...
HOW FAR S THE BUILDING BITTER COLD AIR MASS SPREADS WILL DEPEND ON
THE AMPLITUDE OF THE WRN RIDGE. INCLUDING RECENT OPERATIONAL GFS
RUNS...THERE ARE STILL SOME CANADIAN ENSEMBLES MAINTAINING A STRONG
WRN RIDGE WHICH WOULD FORCE THE BITTER COLD AIR INTO THE UPPER GREAT
LAKES. ON THE OTHER HAND...THERE APPEARS TO SOME OVERALL TRENDING
TOWARD A LESS AMPLIFIED WRN RIDGE WHICH DIMINISHES THE POTENTIAL FOR
AN UNUSUALLY COLD AIR MASS TO DESCEND INTO THE UPPER GREAT LAKES.
WILL BE SOMETHING TO MONITOR OVER THE COMING WEEK. WHATEVER
HAPPENS...THE UPCOMING COLD PATTERN SHOULD BE FAIRLY SHORT LIVED
WITH INDICATIONS OF A RETURN TO ABOVE NORMAL TEMPS DURING THE LAST
HALF OF FEB. AS FOR PCPN...THE DEVELOPING COLD PATTERN WILL
OBVIOUSLY MEAN NEXT WEEK WILL BE AN ACTIVE PERIOD FOR LAKE EFFECT
SNOW OFF LAKE SUPERIOR. PRIOR TO THAT...THERE WILL BE SOME LIGHTER
LES INTO THE EARLY PART OF THE WEEKEND THAT WILL BRIEFLY BE ENHANCED
BY PASSING SHORTWAVE TROF FRI NIGHT/SAT MORNING. SHARP TROF
AMPLIFICATION EARLY NEXT WEEK SHOULD YIELD AT LEAST A WIDESPREAD -SN
ACROSS UPPER MI AS WELL AS LAKE ENHANCEMENT. THERE HAS BEEN A FAIRLY
STRONG SIGNAL FOR MDT TO PERHAPS HVY LES OFF LAKE SUPERIOR TO FOLLOW
THIS SYSTEM INTO TUE AND PERHAPS WED.

BEGINNING FRI...IN THE WAKE OF THE SHORTWAVE THAT PASSES TONIGHT...
LINGERING LES IN THE NW WIND FAVORED SNOW BELTS E OF MARQUETTE FRI
MORNING WILL DIMINISH AS INVERSION FALLS FROM 7-8KFT EARLY TO 4KFT
IN THE AFTN. INITIAL HIGH INVERSION MAY SUPPORT A COUPLE OF INCHES
OF SNOW LOCALLY. WITH INVERSION ALREADY FALLING OUT W BY 12Z...LES
WILL BE LIGHTER. SFC HIGH PRES RIDGE WILL DRIFT ACROSS THE AREA
DURING THE DAY...RESULTING IN THE LINGERING/DIMINISHING LES SHIFTING
OFFSHORE FROM W TO E. WILL BE CLOSE TO 00Z SAT BEFORE ENDING E OF
GRAND MARAIS. WITH THE BACKING WINDS...SHOULD SEE SOME SUNSHINE
WHERE LAKE CLOUDS DEPART...THOUGH INCREASING HIGH CLOUDS AHEAD OF
NEXT SHORTWAVE TROF WILL PREVENT THE DAY FROM BECOMING SUNNY.

AFOREMENTIONED SHORTWAVE TROF AND ASSOCIATED COLD FRONT WILL CROSS
THE UPPER GREAT LAKES LATE FRI NIGHT/SAT MORNING. WHILE MOISTURE
INFLOW WILL BE LACKING...MODELS INDICATE DEEP MOISTENING OF THE
COLUMN/MODEST DEEP LAYER FORCING PER QVECTORS AND WEAK ISENTROPIC
ASCENT THAT SHOULD LEAD TO RELATIVELY HIGH POPS...BUT LOW QPF FRI
NIGHT. WITH 850MB TEMPS AROUND -12C ALONG COLD FRONT WHEN IT PASSES
ACROSS LAKE SUPERIOR...EXPECT A BRIEF BURST OF LAKE ENHANCED SNOW TO
ACCOMPANY ITS ARRIVAL IN UPPER MI LATE FRI NIGHT/SAT MORNING...
ESPECIALLY ACROSS THE NW FCST AREA AND ALSO MOSTLY E OF KMQT AS
WINDS SHIFT NNW. MIGHT SEE 2-3 INCHES OF SNOW WITH THE LAKE
ENHANCEMENT. LES WILL THEN DIMINISH DURING THE DAY SAT UNDER FALLING
INVERSION AND ARRIVAL OF SOME LOW-LEVEL DRYING.

SUN/MON...DOWNSTREAM OF THE AMPLIFYING WRN RIDGE...NEXT SHORTWAVE
WILL DROP MORE SHARPLY INTO THE CNTRL CONUS. RECENT ENSEMBLE AND
OPERATIONAL MEDIUM RANGE MODEL TRENDS ARE FOR THE LOW PRES RESPONSE
AT THE SFC TO BE FARTHER N WHICH WOULD PUSH THE MORE PERSISTENT
SYNOPTIC SNOW SHIELD MOSTLY N OF THE AREA...BUT THAT REMAINS TO BE
SEEN WITH SYSTEM STILL SEVERAL DAYS OUT IN THE MODEL RUNS. IN ANY
EVENT...STILL EXPECT ALL AREAS TO SEE SOME -SN AT TIMES SUN/MON.
LAKE ENHANCEMENT WILL ALSO OCCUR NEAR LAKE SUPERIOR...BUT
TIMING/LOCATION WILL REMAIN UNCERTAIN UNTIL MODELS NARROW IN ON THE
SFC LOW PRES/WIND FIELDS. RIGHT NOW...IT APPEARS SNOW WILL REALLY
BEGIN TO PICK UP NEAR LAKE SUPERIOR OVER THE W ON MON AS WINDS BACK
NORTHERLY AND CAA BEGINS. SNOW WILL THEN INCREASE EASTWARD ACROSS
NCNTRL UPPER MI MON NIGHT/TUE. GFS CONTINUES BE MOST PERSISTENT
HANGING ON TO DEEP MOISTURE ACROSS THE AREA THRU TUE AND THUS IS
MUCH MORE SUPPORTIVE OF A MDT/HVY LES REGIME ACROSS THE N WIND
FAVORED SNOW BELTS THRU TUE. EVEN IF THE DEEP MOISTURE THINS
OUT...850MB TEMPS FALLING INTO THE -15 TO -20C RANGE SUPPORTS GOING
WELL ABOVE CONSENSUS POPS NEAR LAKE SUPERIOR. POPS WERE BUMPED UP
INTO THE CATEGORICAL RANGE W ON MON...THEN ACROSS MOST AREAS NEAR
LAKE SUPERIOR MON NIGHT/TUE. CONTINUED HIGHER THAN CONSENSUS POPS
INTO WED AS WELL.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1239 PM EST THU FEB 4 2016

A WEAK UPPER DISURBANCE AND SURFACE LOW WILL MOVE THROUGH THE AREA
THIS EVENING. SOME LIGHT SNOW IS POSSIBLE WITH MVFR CIGS/VSBYS AT
ALL SITES THIS AFTN INTO THIS EVENING. BEHIND THE LOW...THE WINDS
WILL TURN W-NW WITH SOME LIGHT LAKE EFFECT SNOW POSSIBLE MAINLY AT
CMX/IWD. VSBYS COULD TURN IFR AT CMX FOR A PERIOD OVERNIGHT...BUT AM
NOT EXPECTING ANY LIFR CONDITIONS AT THIS TIME. IMPROVING CONDITIONS
ON FRIDAY WITH HIGH PRES BUILDING INTO THE AREA.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EST THU FEB 4 2016

EXPECT SOME N GALE FORCE GUSTS TO 35 KTS THIS EVENING OVER MAINLY
THE E HALF OF LAKE SUPERIOR UNDER THE TIGHTER PRES GRADIENT ON THE
WESTERN FLANK OF DEPARTING SFC LO PRES. THERE WILL THEN BE A PERIOD
OF RELATIVELY LIGHT...BUT SHIFTING WINDS UNDER 25 KTS THRU THE
WEEKEND AS SEVERAL DISTURBANCES/SURFACE TROFS AND RIDGES PASS THE
WESTERN GREAT LAKES. STRONGER N WINDS THAT COULD REACH GALE FORCE
ARE THEN LIKELY TO DEVELOP NEXT MON AS A DEEPER LO PRES DEVELOPS IN
THE GREAT LAKES AHEAD OF A STRONGER DISTURBANCE.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...ROLFSON
AVIATION...MRD
MARINE...TITUS


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