Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 172344
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
744 PM EDT FRI OCT 17 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 349 PM EDT FRI OCT 17 2014

...A COOL WET AND WINDY EVENING WITH GRADUAL IMPROVEMENT LATER
TONIGHT INTO SATURDAY...

WV LOOP AND IR SATELLITE AND NWS REGIONAL RADAR AND CANADIAN RADAR
LOOPS SHOWING AN EXPANDED AREA OF RAIN SWEEPING NORTH TO SOUTH OVER
UPPER GREAT LAKES. BASED ON SFC OBS...APPEARS BACK EDGE OF RAIN IS
OVR CENTRAL LK SUPERIOR ENE INTO ADJACENT AREAS OF ONTARIO. PRIMARY
SFC LOW IS NOW JUST SOUTH OF JAMES BAY AT AROUND 990MB. NORTH WINDS
OVER THE REGION ARE GUSTING OVER 30 MPH OVER MUCH OF LK SUPERIOR AND
OVER PARTS OF NORTHERN UPR MICHIGAN...WITH 20-30 MPH GUSTS FARTHER
INLAND AND TOWARD LK MICHIGAN. BASED ON UPSTREAM TRENDS...SHORT
TERM MODEL FORECASTS FM NAM/GEM-REGIONAL SEEM IN GOOD SHAPE..AND
HAVE LEANED ON THOSE ALONG WITH THE HRRR FOR DETAILS IN THE NEXT
12-15 HRS. EXPECT A PERIOD OF RAIN AND STRONG WINDS THROUGH AT LEAST
THE EARLY EVENING BEFORE PRECIP DIMINISHES THROUGH THE OVERNIGHT AS
MOISTURE ABOVE H9 DIMINISHES SHARPLY. EVEN WITH THE DECREASE IN
MID-UPPER LEVEL MOISTURE...ABUNDANT LOW-LEVEL MOISTURE WILL REMAIN
INTO MUCH OF SATURDAY ALONG WITH A NNW LOW-LEVEL FLOW BTWN DEPARTING
LOW AND APPROACHING SFC HIGH. LAKE ENHANCED PRECIP THIS EVENING
/DELTA T/S AROUND 8C GIVEN SUFFICIENT LARGE SCALE MOISTURE AND LIFT/
SHOULD TRANSITION TO PURE LAKE EFFECT SINCE THERE IS JUST ENOUGH
OVER-WATER INSTABILITY PRESENT AS TEMPS AT INVERSION TOP 900-875MB
FALL TO -5C AFTER 09Z WHILE WATER TEMPS ON AVERAGE ARE AROUND +8C
/PROVIDING DELTA T/S OF 13C/.

BASED ON SOUNDINGS...ANY SNOW POTENTIAL IS BASED ON EXTENT OF
WARMING IN LOWEST PARTS OF THE BLYR. THUS CONTINUED TO USE WBZERO
HEIGHTS TO DETERMINE THE POTENTIAL FOR SNOW. APPEARS THAT HIGHER
TERRAIN AREAS OF WEST AND CNTRL CWA SEE THE BEST CHANCES FOR SOME
SNOW...BUT WITHOUT DEEPER MOISTURE/LIFTING OCCURRING...SEEMS THAT
TEMPS IN MOIST LAYER MAY NOT BE AS LOW AS -8C OR -10C...SUGGESTING
THERE MAY NOT BE ICE CRYSTALS INTRODUCED FM ALOFT TO LEAD TO BETTER
CHANCES OF SNOW. A WEAK WAVE ALOFT CURRENTLY DROPPING SE OVER CNTRL
MANITOBA MAY PUSH ACROSS WEST CWA LATER TONIGHT RESULTING IN A BIT OF
ADDITIONAL H7-H5 Q-VECTOR CONVERGENCE AND LIFT TO HELP OUT THE CAUSE.
EVEN IMPACT FM THAT APPEARS MINIMAL ATTM. OVERALL...CHANCES OF
MEASURABLE SNOW APPEAR MINIMAL WITH THIS SYSTEM.

SOUNDINGS CONTINUE TO SHOW MOISTURE TRAPPED BENEATH INVERSION AT
H85-H8 ON SATURDAY. KEPT IN SMALL POPS FOR LAKE EFFECT AS SETUP IS
NOT ALL THAT DIFFERENT FM LATE TONIGHT. GRADUALLY...AS HIGH PRESSURE
RIDGING BUILDS OVER THE AREA...EXPECT BLYR TO DRY OUT BLO CLOUD BASE
ENOUGH TO RESULT IN ANY LGT PRECIP COMING TO AN END. TEMPS WILL BE
CHILLY AS LOW-LEVEL THERMAL TROUGH IS OVERHEAD. EXPECT MAX TEMPS
MAINLY IN THE 30S...EXCEPT SOME LOW 40S OVER SCNTRL CWA. ADDED TO
THE CHILL WILL BE CONTINUING GUSTY NORTH TO NORTHWEST WINDS...
STRONGEST NEAR LK SUPERIOR OVER THE EAST CWA IN THE MORNING.

LIKELY THE BIGGEST POTENTIAL IMPACT FM THIS SYSTEM WILL BE WINDS AND
WAVE ACTION ALONG LK SUPERIOR. GIVEN THE HIGH WATER LEVELS ON LAKE
SUPERIOR WHICH ARE THE HIGHEST SINCE THE MID 1990S AND WAVES
BUILDING TO 8-12 FEET INTO THIS EVENING AND THROUGH TONIGHT (HIGHEST
E OF THE KEWEENAW)...MINOR BEACH EROSION AND LOCALIZED FLOODING IS
POSSIBLE...ESPECIALLY ON THE BEACHES FROM AROUND MARQUETTE TO GRAND
MARAIS. THIS WILL CONTINUE TO BE MENTIONED IN HAZARDOUS WEATHER
OUTLOOK AND THE GRAPHICAL EHWO.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 307 PM EDT FRI OCT 17 2014

NAM SHOWS A 500 MB TROUGH OVER THE EASTERN U.S. 00Z SUN. THERE IS A
SHORTWAVE OVER THE CANADIAN PRAIRIES 00Z SUN THAT AFFECTS THE UPPER
GREAT LAKES LATE ON SUN. A 500 MB RIDGE THEN BUILDS INTO THE PLAINS
ON MON. NAM SHOWS SOME DEEPER MOISTURE AND 850-500 MB Q-VECTOR
CONVERGENCE MOVING INTO THE AREA LATE SUN AND THEN MOVING OUT ON
MON. NAM SHOWS SOME ISENTROPIC LIFT AND MOISTURE ON I290K-I305K
SURFACES MOVING INTO THE AREA SUN AFTERNOON AND EVENING BEFORE
MOVING OUT ON MON. WILL KEEP SOME LOW CHANCE POPS SUN MORNING
GRADUALLY SPREADING ACROSS THE AREA SUN AFTERNOON INTO EVENING AND
THEN DRYING OUT LATE MONDAY. DID NOT MAKE TOO MANY CHANGES TO THE
TEMPERATURES OR THE WEATHER AS THE FORECAST HAD THINGS WELL IN HAND.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH ON THE WEST
COAST 12Z TUE WITH A RIDGE OVER THE PLAINS AND A TROUGH IN THE ERN
U.S. THE RIDGE BUILDS INTO THE UPPER GREAT LAKES 12Z WED INTO 12Z
THU WITH RIDGING STAYING IN PLACE INTO FRI. THIS FORECAST PERIOD
WILL BE DRY WITH A WARMING TREND WITH TEMPERATURES GOING ABOVE
NORMAL.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 744 PM EDT FRI OCT 17 2014

STRONG NORTHERLY UPSLOPE WINDS AND PCPN WILL RESULT IN LOWER END MVFR
THROUGH THE EVENING. THE STRENGTHENING NORTHERLY WINDS WILL BE
STRONGEST AT SAW THIS AFTN/EVENING WITH GUSTS APPROACHING 30KT. AS
DRIER AIR BEGINS TO FLOW INTO THE AREA TONIGHT...ESPECIALLY
OVERNIGHT...CIGS SHOULD LIFT AOA 2K FT AT ALL TERMINALS WITH
PCPN DIMINISHING OR ENDING. IMPROVEMENT WILL OCCUR FIRST AT KCMX AND
LAST AT SAW AS MOISTURE THINS OUT THERE LATEST. ALTHOUGH LAKE
MOISTURE WILL DELAY CLEARING...EXPECT VFR CONDITOINS BY LATE MORNING
AT IWD AND CMX AND BY LATE AFTERNOON AT SAW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 PM EDT FRI OCT 17 2014

GALES 35-40 KTS REMAIN ON TRACK OVER LK SUPERIOR THROUGH TONIGHT AS
LOW PRESSURE DEEPENS SOUTHEAST OF JAMES BAY. WINDS JUST STARTING TO
INCREASE ON BAY OF GREEN BAY AND LK MICHIGAN AND EXPECT FREQUENT
GALE GUSTS THROUGH MUCH OF THE NIGHT THERE. AS A HIGH PRES RIDGE
BUILDS OVER THE AREA ON SATURDAY AFTN...STRONG WINDS WILL DIMINISH
WEST TO EAST. ALTHOUGH ANOTHER DISTURBANCE/SURFACE LOW PRESSURE WILL
TRACK ACROSS THE UPPER LAKES EARLY NEXT WEEK...NO STRONG WINDS ARE
EXPECTED.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WARNING UNTIL 11 AM EDT SATURDAY FOR LSZ266-267.

  GALE WARNING UNTIL 6 AM EDT SATURDAY FOR LSZ244-245-248>251-264-
     265.

  GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR LSZ242-243-246-247-
     263.

LAKE MICHIGAN...
  GALE WARNING UNTIL 8 AM EDT SATURDAY FOR LMZ221-248-250.

&&

$$

SHORT TERM...JLA
LONG TERM...07
AVIATION...JLB
MARINE...JLA






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