Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 241228
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
728 AM EST MON NOV 24 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 537 AM EST MON NOV 24 2014

WV IMAGERY AND RUC ANALYSIS SHOWS A MID-UPR LEVEL TROUGH OVER THE
NRN/CENTRAL PLAINS WITH A COUPLE OF STRONG SHORTWAVES OUT AHEAD OF
THIS TROUGH IN A SW FLOW. ONE SHORTWAVE WAS MOVING ACROSS LAKE HURON
NEARLY CO-LOCATED WITH THE 980 MB SFC LOW WHILE ANOTHER SHORTWAVE
WAS TRIGGERING THUNDERSTORMS AS IT LIFTED THROUGH SRN IL AND SRN IN.
DEFORMATION PCPN SHIELD IN COMMA HEAD OF LAKE HURON SHORTWAVE HAS
BEEN RESPONSIBLE FOR THE LIGHT PCPN OVER MUCH OF WEST AND CENTRAL
UPPER MI THIS MORNING WITH SOME MODERATE RAIN OVER ERN UPPER MI. THE
RAIN OVER THE EXISTING SNOW PACK CONTINUES TO SUPPORT AREAS OF FOG
BUT VSBYS OVER MOST AREAS HAVE RISEN ENOUGH TO CANCEL DENSE FOG
ADVISORY.

TODAY...MODELS AND REGIONAL RADAR IMAGERY SUGGEST THAT THERE MAY BE
A LULL IN THE PCPN BETWEEN THE EXITING NRN LAKE SHRTWV AND THE MID
LEVEL TROUGH MOVING IN FROM THE UPPER MS VALLEY/NRN PLAINS. AS THE
DEEPENING SFC LOW OVER LAKE HURON LIFTS QUICKLY NE THE COLDER AIR
WILL ALSO SLIDE QUICKLY THROUGH UPPER MI WITH THE RAIN CHANGING OVER
TO SNOW FROM 12Z-21Z FROM W TO EAST PER MODEL SNDGS AND 1000-850 MB
LOW-LVL LEVEL THICKNESS. WITH THE LOSS OF THE STRONGER LARGE SCALE
FORCING/DEEP LAYER Q-VECT CONVERGENCE TIL AFTERNOON EXPECT MAINLY
JUST LIGHT TO MODERATE LAKE ENHANCED SNOW OVER THE WEST HALF FOR NNW
FLOW FAVORED LOCATIONS AS 850 MB TEMPS FALL TO NEAR -8C WEST BY 18Z
AND TO AROUND -12C ACROSS WEST AND NCNTRL LOCATIONS BY 00Z. EXPECT
SNOWFALL AMOUNTS IN THE 2 TO 3 RANGE OVER THE WEST WITH GENERALLY
1-2 INCHES NCNTRL...EXCEPT UP TO 3 INCHES POSSIBLE OVER THE HURON
MOUNTAIN AREA. A TIGHT GRADIENT BEHIND THE LOW WILL BRING STRONG
NRLY WINDS WITH GUSTS TO 30-40 MPH PRODUCING SOME BLOWING AND
DRIFTING SNOW.

TONIGHT...MODELS CONTINUE TO SHOW DEEP MOISTURE/Q-VECTOR CONVERGENCE
AS MID-LVL TROUGH LINGERS OVER THE AREA. ALSO MODEL SOUNDINGS
SUGGEST THE POTENTIAL FOR GOOD SNOW GROWTH AT LEAST THIS EVENING AS
BEST MODEL OMEGA/LIFT INTERSECTS DGZ. CONVERGENT NNW FLOW WILL FAVOR
3-5 INCH ACCUMULATIONS OVER THE HIGHER TERRAIN OF THE WEST AND
NCNTRL COUNTIES WITH PERHAPS ISOLATED 6 INCH AMOUNTS POSSIBLE OVER
THE HURON MOUNTAINS. LAKE ENHANCED SNOW MAY TAPER OFF OVER THE WRN
COUNTIES LATE TONIGHT AS BEST FORCING/Q-VECT CONV BEGINS TO SHIFT
EAST.

CURRENT LAKE EFFECT SNOW ADVISORIES STILL ON TRACK FOR ALL OF WEST
AND NORTH CENTRAL UPPER MI WITH THE GREATEST SNOW TOTAL
ACCUMULATIONS OF 5 TO 9 INCHES EXPECTED OVER HIGHER TERRAIN
LOCATIONS NEAR LAKE SUPERIOR INTO TUESDAY. SOME ISOLATED 10" AMOUNTS
MAY BE POSSIBLE OVER THE HURON MOUNTAINS AIDED BY UPSLOPE FM THE
HIGHER TERRAIN THERE.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 413 AM EST MON NOV 24 2014

LIGHT TO MODERATE LAKE EFFECT WILL BE ONGOING TO START TUESDAY MORNING
WITH DELTA T/S OVER 15C AND NNW LOW-LEVEL WINDS IN WAKE OF THE
DEPARTING SFC LOW PRESSURE TROUGH. INVERSIONS UP TO 5KFT DOES PUT MOST
OF THE CLOUD BEARING LAYER IN THE DGZ...BUT WITH INCREASING DRYING
AND SUBSIDENCE ALOFT AS MAIN SHORTWAVE MOVES EAST...EXPECT THE LAKE EFFECT
TO DIMINISH THROUGH THE DAY AS LOW-LEVEL WINDS BECOME ANTICYCLONIC
AS RIDGE MOVES IN. ENDING TIMES FOR CURRENT LAKE EFFECT ADVISORIES
SEEM GOOD BASED ON THE DIMINISHING TRENDS IN SNOW SHOWERS AND WINDS/BLSN.

TUESDAY NIGHT INTO WEDNESDAY ONE SHORTWAVE AND A LOW PRESSURE SYSTEM
IS EXPECTED TO DIP ESE FM THE NORTHERN PLAINS TOWARD THE MIDDLE
MISSISSIPPI RIVER VALLEY. SWATH OF SNOW SHOULD ACCOMPANY THIS LOW
PRESSURE AREA AND THAT SHOULD STAY MAINLY SOUTH OF UPPER MICHIGAN.
INVERTED SFC TROUGH WILL BE PRESENT TO THE NORTH OF THE MAIN SFC LOW
AND THAT WOULD EXTEND INTO UPR MICHIGAN. SHORTWAVE LIKELY TO BE THE
MAIN FOCUS FOR THE WEATHER OVR CWA ON WEDNESDAY INTO THANKSGIVING IS
IN THE NORTHERN STREAM AND SLIDES OVER THE AREA FM SOUTHERN MANITOBA
AND NORTHWEST ONTARIO IN THE AFTN. OVERALL...PREFER THE OVERALL IDEA
OFFERED BY THE NAM/GFS/ECMWF COMPARED TO THE GEM-NH AS THAT MODEL
SEEMS TOO PHASED WITH THE NORTHERN STREAM AND SOUTHERN STREAM
SHORTWAVES WITH THE RESULT THAT THE THE MAIN SFC LOW IS TOO FAR
NORTH. ECMWF CONTINUES TO SHOW SHARPER TROUGH/CONVERGENCE AND LAKE
ENHANCED SNOW FOR NORTHWEST CWA NOT UNTIL WED NIGHT THEN OVER NCNTRL
CWA ON THANKSGIVING DAY. GFS CONTINUES TO INDICATE WEAKER OVERALL
SYSTEM BUT DOES BRING THE NORTH WIND LAKE EFFECT SNOW SHOWERS IN
EARLIER...MORE SO ON WEDNESDAY AFTN INTO WEDNESDAY NIGHT. GIVEN COLD
POOL OF AIR TO NORTH OF THE SFC TROUGH WITH H85 TEMPS DOWN TO AS LOW
AS -20C THERE WILL BE CERTAINLY BE SOME LAKE EFFECT SNOW SHOWERS
WEDNESDAY INTO THANKSGIVING. IN ADDITION...WILL NEED TO WATCH LAKE
EFFECT OFF LK MICHIGAN IN THE S/SE WINDS AHEAD OF THE SFC TROUGH.
WINDS BACK STEADILY FROM LATE TUESDAY NIGHT INTO WEDNESDAY OVER
NORTHERN LK MICHIGAN. FORECAST SOUNDINGS POINT TO SCT LAKE EFFECT TO
EXPAND OVER MUCH OF THE EASTERN CWA BY LATE WEDNESDAY AS THE ONSHORE
FLOW IS ENHANCED BY THE LARGER SCALE LIFT AND MOISTURE FM THE NEARING
NORTHERN STREAM SHORTWAVE.

SHARPNESS OF SFC TROUGH AND EXTENT OF CONVERGENCE STILL UNCERTAIN
THOUGH WHICH AFFECTS INTENSITY/EXTENT OF THE LES BOTH OFF LK
SUPERIOR AND LK MICHIGAN AND ALSO THE STRENGTH OF WINDS/BLSN NEAR LK
SUPERIOR IN WAKE OF TROUGH. LATEST RUNS OF GFS AND ECMWF KEEP WITH
CONTINUITY COMPARED TO THEIR PREVIOUS RUNS...GIVING NO TREND TO
LATCH ON. THOSE THAT HAVE TRAVEL PLANS WEDNESDAY INTO THANKSGIVING
NEAR LK SUPERIOR AND ALSO OVER MOST OF THE EAST HALF OF UPR MICHIGAN
SHOULD BE AWARE THAT DURING THIS TIME FRAME THERE COULD AT LEAST
LOCALIZED HIGHER IMPACT WEATHER.

HIGH PRESSURE DIVING OVER THE PLAINS WITH RIDGING OVER NORTHERN
ONTARIO EVENTUALLY SHOULD WIN OUT LATER ON THANKSGIVING. THOUGH IF
THE STRONGER TROUGH FM ECMWF IS CORRECT...DIMINISHING TREND IN THE
LAKE EFFECT WOULD BE MORE ON THURSDAY NIGHT. ONCE THE SFC RIDGE
SLIDES EAST ON FRIDAY...UPPER FLOW FLATTENS OUT ALLOWING FOR WARM
AIR ADVECTION TO RAMP UP OVER THE PLAINS. INDICATIONS THAT AT LEAST
ONE SHORTWAVE WILL ALSO BE PROPELLING FROM THE NORTHERN PLAINS
TOWARD THE WESTERN GREAT LAKES. DECENT JET STREAK ALSO FCST OVER THE
PLAINS WHICH SHOULD ENHANCED LIFT ALONG THE TIGHT LOW-LEVEL
BAROCLINIC ZONE. SWATH OF AT LEAST LIGHT SNOW SHOULD RESULT
SOMEWHERE VCNTY OF NORTHERN PLAINS TO THE WESTERN GREAT LAKES.
CONSIDERING THE WAVE THAT WILL GENERATE THE SNOW IS STILL TO EMERGE
FROM UPPER TROUGH OVER NORTHERN PACIFIC VCNTY OF 40N/155W...GFS IS
CONSISTENT IN SHOWING THIS AND GEM-NH IS THERE AS WELL. ECMWF JUST
TRENDED THIS WAY WITH THE 23NOV/12Z RUN. PLENTY OF TIME TO LOOK AT
THE DETAILS BUT DOES APPEAR THAT PTYPE WILL STAY ONLY SNOW AS WARM
AIR AT H85 IS FORECAST TO REMAIN SOUTHWEST OF UPPER LAKES.

MIXED SIGNALS THAT COULD SEE SOME LGT MIXED PRECIP FRIDAY NIGHT INTO
SATURDAY AS THE H9-H8 WARM LAYER ARRIVES. COULD SEE SOME DRIZZLE AND
FOG ISSUES TOO THOUGH AT LEAST RIGHT NOW...GFS/ECMWF ARE NOT SHOWING
DWPNTS AS HIGH AS ARE CURRENTLY OCCURRING OVER AREA. REAL MODEL
DIFFERENCES TO CLOSE THE LONG TERM...WITH 23NOV/12Z ECMWF KEEPING
THE WARM SECTOR OVER THE AREA INTO SUNDAY...WHILE THE GFS SHOVES
SHARPER COLD FRONT OVER THE UPPER GREAT LAKES BY SUNDAY. AT 12Z
SUNDAY...H85 TEMPS VARY FROM -5C OFF THAT RUN OF ECMWF TO -24C
OFF THE GFS. LATEST ECMWF TRENDED TOWARD GFS AS IT NOW SHOWS H85
TEMP THAT SAME TIME OF -16C. USED A CONSENSUS OF THE MODELS UNTIL
THE DIFFERENCES ARE RESOLVED...BUT GIVEN THE TREND FM THE LATEST
ECMWF...WENT WITH A BIT HIGHER POPS AND LOWERED TEMPS SLIGHTLY.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 721 AM EST MON NOV 24 2014

EXPECT LIFR CIGS TO PERSIST THROUGH THIS MORNING. AS A DEEP LOW
PRESSURE SYSTEM MOVES NORTHEAST OF THE AREA THIS MORNING WINDS WILL
BECOME NNW AND QUICKLY STRENGTHEN WITH ANY RAIN CHANGING TO SNOW.
CIGS MAY IMPROVE SOME THRU PD WITH INCREASED MIXING FROM INFLUX OF
COLDER AIR AND STRONGER WINDS. EXPECT LOWER IFR VSBY ONCE HEAVIER SNOW
SETS UP THIS AFTERNOON INTO THIS EVENING WITH IMPROVEMENT LATE
TONIGHT FROM WEST AS RIDGE BEGINS TO BUILD IN AND SNOW TAPERS OFF.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 537 AM EST MON NOV 24 2014

A DEEPENING LOW WILL MOVE TO EAST OF LAKE SUPERIOR TODAY. NORTHERLY
WINDS WILL INCREASE TO GALES 35-45 KTS BY THIS MORNING INTO MONDAY
NIGHT. EXPECT WINDS TO DIMINISH TO 25 KTS OR LESS TUESDAY INTO
WEDNESDAY...THEN INCREASE TO 30 KTS WED NIGHT INTO THURSDAY AS COLD
AIR POURS ACROSS LAKE SUPERIOR BETWEEN HIGH PRESSURE BUILDING OVER
THE NORTHERN PLAINS AND LOW PRESSURE CROSSING THE LOWER GREAT LAKES.
THERE MAY BE A BRIEF PD OF GALES TO 35 KNOTS OVER NCNTRL LAKE
SUPERIOR WED NIGHT. WINDS WILL DECREASE TO LESS THAN 25 KNOTS THU
NIGHT INTO FRI AS A HIGH PRES RIDGE MOVES OVER THE UPPER LAKES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM EST
     TUESDAY FOR MIZ006-007-085.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST /6 AM CST/ TUESDAY FOR
     MIZ001>003-009.

  LAKESHORE FLOOD ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST
     TUESDAY FOR MIZ001-003-005>007.

  LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST
     TUESDAY FOR MIZ004-005.

LAKE SUPERIOR...
  GALE WARNING FROM 3 PM THIS AFTERNOON TO 4 AM EST TUESDAY FOR
     LSZ251-267.

  GALE WARNING UNTIL 4 AM EST TUESDAY FOR LSZ246>250-265-266.

  GALE WARNING UNTIL 2 AM EST TUESDAY FOR LSZ242>245-263-264.

  GALE WARNING FROM NOON EST /11 AM CST/ TODAY TO 9 PM EST /8 PM
     CST/ THIS EVENING FOR LSZ162.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...VOSS
MARINE...VOSS





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