Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 261942
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
342 PM EDT SUN OCT 26 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM EDT SUN OCT 26 2014

UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW SOUTH OF JAMES BAY
WITH A RIDGE OVER THE CENTRAL U.S. THIS MORNING. THE RIDGE MOVES
INTO THE UPPER GREAT LAKES BY THIS EVENING. THE TROUGH IN THE
PACIFIC NW THIS MORNING WILL HEAD EAST INTO THE NORTHERN ROCKIES
LATE TONIGHT. NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE AND
DEEPER MOISTURE LATE TONIGHT ACROSS THE CWA. NAM SHOWS SOME
ISENTROPIC LIFT AND MOISTURE ON I290K-I305K SURFACES LATE TONIGHT
OVERSPREADING MOST OF THE CWA WITH DRY LOW LEVEL AIR REMAINING OVER
THE EAST.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. DRY AIR OVER
THE EAST IS A CONCERN AND HELD OFF ON POPS OVER THE EASTERN CWA
TONIGHT AND WENT DRY. KEPT IN CHANCE POPS OVER THE WEST HALF TONIGHT
WITH DRY AIR IN THE LOW LEVELS REMAINING INTO THIS EVENING. KEPT IN
THUNDER POSSIBILITY FOR LATE TONIGHT AS THERE IS SOME INSTABILITY
ALOFT.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM EDT SUN OCT 26 2014

THE FORECAST FOR MON NIGHT/TUE REMAINS SOMEWHAT UNCERTAIN DUE TO
MODEL DISAGREEMENT WITH SHORTWAVE ENERGY /AND RESULTING
CYCLOGENESIS/ ROTATING AROUND AN UPPER TROUGH MOVING THROUGH THE
REGION. THE REAL DIFFERENCES ARE DUE TO THE PLACEMENT OF THE
SHORTWAVE. THE GFS KEEPS THE BEST ENERGY FARTHER N...RESULTING IN
THE DRY SLOT BEING OVER THE CWA MUCH OF MON NIGHT AND TUE. ON THE
OTHER HAND...THE NAM IS MUCH FARTHER S...RESULTING IN A DEEPER SFC
LOW THAT MOVES FROM CENTRAL LAKE MICHIGAN TO ERN UPPER MI...WHICH
MEAN MORE RAIN. THE ECMWF IS BETWEEN THE NAM AND GFS AND ONLY BRINGS
THE DRY SLOT INTO FAR SRN PORTIONS OF THE CWA...RESULTING IN A
WETTER FORECAST THAN THE GFS. VERY DIFFICULT TO LEAN TOO FAR ONE WAY
OR ANOTHER AT THIS POINT GIVEN UNCERTAINTIES WITH SHORTWAVE ENERGY
AND SFC CYCLOGENESIS...SO WILL GO WITH A CONSENSUS BLEND.
ADDITIONALLY...TUE WILL END UP BEING GUSTY...BUT THE EXTENT OF SUCH
DEPENDS LARGELY ON THE TRACK/STRENGTH OF THE SFC LOW...SO HARD TO
GET TOO SPECIFIC ON EXPECTED GUSTS AT THIS POINT. THE KEWEENAW
SHOULD SEE THE STRONGEST WINDS OVER UPPER MI DUE TO THE FAVORABLE
WLY WINDS DIRECTION.

TUE NIGHT INTO THU NIGHT...THE SYSTEM THAT MOVED THROUGH ON TUE WILL
MOVE INTO NRN QUEBEC BY LATE WED AS A SFC RIDGE MOVES TO THE WRN
CWA. FORECAST CONFIDENCE IMPROVES DURING THIS TIME AS CONDITIONS
TRANSITION TO A MORE FAVORABLE LAKE EFFECT/ENHANCED RAIN/SNOW
SETUP...WHICH ENTAILS LESS MODEL VARIABILITY IN THIS CASE. BOUNDARY
LAYER WINDS WILL BE FROM THE NW...BUT WILL START TO BACK TO THE W
/FROM W TO E/ ON WED AFTERNOON AS THE RIDGE MOVES IN. THERE WILL BE
AMPLE LOW LEVEL MOISTURE WRAPPING AROUND THE BACK SIDE OF THE
PREVIOUS SYSTEM INTO WED MORNING...BUT DRIER AIR WILL START TO
BECOME MORE DOMINANT ON WED. AS FOR TEMPS...850MB TEMPS WILL FALL
FROM AROUND -2C AT 00Z WED TO AROUND -6C AT 12Z WED. DURING THE DAY
ON WED...850MB TEMPS WILL FALL A COUPLE OF DEGREES OVER ERN LAKE
SUPERIOR WHILE WARMING A COUPLE OF DEGREES OVER THE WRN LAKE.
OVERALL...LOOKS LIKE A GOOD SETUP FOR LAKE EFFECT RAIN...WITH SNOW
BECOMING MORE LIKELY IN OVER THE HIGHER TERRAIN LATE TUE NIGHT AND
TO A LESSER EXTENT ON WED. SHOULD SEE A DIMINISHING TREND TO PRECIP
ON WED...ESPECIALLY OVER THE WRN CWA. DO NOT EXPECT TO SEE ANY
SIGNIFICANT SNOW ACCUMULATIONS.

STILL A LOT OF UNCERTAINTY FOR LATE IN THE WEEK GIVEN POOR MODEL RUN
TO RUN CONTINUITY AND MODEL DISAGREEMENT...COMBINED WITH THE USUAL
CAVEATS WITH SHORTWAVES 5 DAYS OUT. THE GFS BRINGS THE SHORTWAVE
RIGHT ACROSS THE CWA...WHILE THE ECMWF MOVES THE SHORTWAVE FARTHER
SW. IN ANY CASE...MODELS HAVE SHOWN POOR RUN TO RUN CONTINUITY WITH
THE SHORTWAVE ITSELF...SO SYNOPTIC PRECIP IS HIGHLY UNCERTAIN.
THANKFULLY...THERE IS HIGHER CONFIDENCE WITH LAKE EFFECT SNOW DUE TO
MODEL AGREEMENT ON NNW LOW LEVEL WINDS AND 850MB TEMPS AOB -10C FOR
MUCH OF FRI AND POSSIBLY INTO FRI NIGHT. THE LES SHOULD RAMP UP THU
NIGHT WHEN THE COLDER AIR SURGES INTO THE AREA /DEPENDENT ON
SHORTWAVE TIMING AS WELL/ AND SHOULD DIMINISH FRI NIGHT INTO SAT AS
A SFC RIDGE MAY SHIFT ACROSS THE CWA. COULD SEE SOME LIGHT
ACCUMULATIONS IN NNW WIND SNOWBELTS EVEN IF THE SHORTWAVE DOES NOT
DIRECTLY IMPACT THE CWA...BUT WOULD BE GREATER IF THE SHORTWAVE DOES
IMPACT THE AREA. SHOULD ALSO BE WINDY FOR AT LEAST A SHORT PERIOD
THU NIGHT INTO FRI /DEPENDING ON THE TRACK AND STRENGTH OF THE
SHORTWAVE/ AS A 1030MB SFC HIGH MOVES FROM THE WNW FAIRLY QUICKLY
BEHIND THE SHORTWAVE. SHOULD SEE A QUICK PERIOD OF GALES FROM THE
EVENT...BUT WILL HAVE TO WAIT UNTIL THINGS BECOME MORE CERTAIN TO
GET TOO SPECIFIC ON WINDS SPEEDS.

SHOULD SEE ANY REMAINING LAKE EFFECT PRECIP DIE OUT/MOVE OUT ON SAT
AS MODELS SHOW THE SFC HIGH SHIFT E OF THE CWA. WILL RUN WITH A
CONSENSUS OF GUIDANCE FOR SAT NIGHT INTO SUN...WHICH WILL SHOW A
WARMING TREND AS AN UPPER RIDGE PUSHES IN FROM THE W.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 121 PM EDT SUN OCT 26 2014

ALTHOUGH HIER CLDS WL BE ON THE INCRS LATER THIS AFTN/THIS EVNG IN
ADVANCE OF AN APRCHG WARM FNT...EXPECT VFR CONDITIONS TO PREVAIL
WITH DRYNESS OF LLVL AIRMASS SHOWN ON LOCAL 12Z RAOBS. BUT AS THE
INCRSG SSE WIND AHEAD OF THE WARM FNT DRAWS MORE MSTR INTO THE UPR
LKS...SOME -SHRA WL DVLP LATE TNGT. CLD BASES WL LOWER...BUT
LINGERING NEAR SFC DRY LYR SHOULD MAINTAIN A VFR CIG. RETAINED
MENTION OF MARGINAL LLWS AT IWD WITH CLOSER APRCH OF THE WARM
FNT/INVRN AND EXPECTED STRONGER LLJ AT THAT LOCATION. AFTER 12Z
MON...THE LLVLS WL MOISTEN SUFFICIENTLY TO WARRANT FCST MVFR CIGS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 326 PM EDT SUN OCT 26 2014

HIGH PRESSURE MOVING INTO THE REGION WILL LEAD TO DECREASING WINDS
TODAY. AFTER A BRIEF PERIOD WITH WINDS LESS THAN 20 KTS WITH THE
HIGH PRESSURE...SE WINDS INCREASE TO 30 KTS OVER MAINLY EASTERN LAKE
SUPERIOR ON MONDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. ONCE
THIS LOW MOVES TO THE EAST OF LAKE SUPERIOR ON TUESDAY...WEST WINDS
TO 30 KTS AND POSSIBLY UP TO GALE FORCE OF 35 KTS WILL DEVELOP LATE
TUESDAY INTO TUESDAY NIGHT. WINDS WILL THEN SHIFT NORTHWEST AND STAY
UP TO 30 KTS INTO WEDNESDAY...BEFORE GRADUALLY DIMINISHING TO LESS
THAN 25 KTS BY WEDNESDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM MAY MOVE
THROUGH THE REGION LATE THIS WEEK...POSSIBLY LEADING TO GALES TO 35
KTS.
&&

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

$$

SHORT TERM...07
LONG TERM...TITUS
AVIATION...KC
MARINE...TITUS






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