Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 291014
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
614 AM EDT WED OCT 29 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 512 AM EDT WED OCT 29 2014

...LIGHT LAKE EFFECT RAIN AND SNOW SHOWERS INTO TONIGHT...

SHORTWAVE TROUGH SLIDING OVER NORTHERN ONTARIO AND THE UPPER GREAT
LAKES THIS MORNING. IR SATELLITE HAS SHOWN GRADUAL WARMING CLOUD
TOPS OVERNIGHT AS STRONGEST FORCING RIDES CLOSER TO 991MB SFC LOW
VCNTY OF JAMES BAY. COLD FRONT EXTENDS TO SOUTHWEST OF THAT LOW AND
IS COMING ASHORE TO THE EAST OF MARQUETTE AT 0830Z. 00Z KINL
SOUNDING SHOWED MOIST PROFILE TO H6 THOUGH LAPSE RATES WERE NOT AS
STEEP AS NAM/GFS INITIALIZED. H85 TEMPS FALL TO -5C BY MID MORNING
AND WILL STAY STEADY OR COOL SLIGHTLY THIS AFTN INTO THIS EVENING.
HAVE SEEN A SMATTERING OF RAIN AND SNOW SHOWERS OVERNIGHT...WITH
MOSTLY SNOW OVER WESTERN CWA PER AVAILABLE WEBCAMS. WAKEFIELD MDOT
CAM HAS SHOWN SNOW IN THE AIR MOST OF EARLY MORNING HOURS. CYCLONIC
NW FLOW IN WAKE OF COLD FRONT ALONG WITH DEEP MOISTURE AND H85 TEMPS
AROUND -4C IS LIKELY LEADING TO LAKE ENHANCEMENT FOR WESTERN CWA AS
DELTA T/S ARE AROUND 10C /8C IS NEEDED FOR LAKE ENHANCEMENT GIVEN
ADEQUATE LARGER SCALE MOISTURE AND FORCING/.

EXPECT THIS SETUP TO BECOME LESS FAVORABLE THROUGH THE MORNING IN
THE WEST AS THE DEEPER MOISTURE DECREASES /WARMING SEEN ON THE IR
SATELLITE/ AND THIS WILL LEAVE MOISTURE THROUGH H9-H85 AND TEMPS AT
4KFT INVERSION AROUND -5C. THIS WILL BE NOT ENOUGH INSTABILITY FOR
PURE LAKE EFFECT PROCESSES AS DELTA T/S STAY AROUND 10C. /TYPCIALLY
LIKE TO SEE DELTA T/S OF 13C OR HIGHER FOR ENOUGH INSTABILITY FOR
LAKE EFFECT/. OVER CNTRL AND EAST...SIMILAR FATE WILL OCCUR TO THE
LAKE ENHANCEMENT REGIME BUT IT WILL NOT BE UNTIL MID MORNING CNTRL
AND MORE IN THE AFTN FOR THE EASTERN CWA. WBZERO HEIGHTS 500-1000 FT
AGL RESULT IN MIXED RAIN AND SNOW...BUT IT SHOULD STAY MAINLY SNOW
OVER FAR WEST WITH LOWER WBZERO HEIGHTS. KEPT POPS HIGH OVR NCNTRL
IN THE MORNING AND INTO EARLY AFTN FOR AREAS FAVORED BY NW WINDS
MAINLY TO THE EAST OF MARQUETTE...INCLUDING MUNISING/SENEY/GRAND
MARAIS AND NEWBERRY. SINCE PRECIP RATES WILL BE LIGHT TODAY AND
TEMPS ARE STILL IN UPPER 30S...NO REAL SNOW ACCUMULATION IS EXPECTED
TODAY. CLOUDS AND GUSTY WINDS WILL MAKE IT FEEL PRETTY CHILLY. HIGHS
UPR 30S WEST/NORTHWEST/NCNTRL AND WELL INTO THE 40S SCNTRL WHERE
SOME CLEARING IS EXPECTED THIS AFTN.

SMALL POPS FOR LINGERING LAKE EFFECT NEAR LK SUPERIOR THIS EVENING
THOUGH WINDS WILL BE BECOMING LIGHT AND THERE IS MORE DRYING BENEATH
A LAKE EFFECT CLOUD DECK THAT WILL BE THINNING OVER TIME. LATE TONIGHT
SHORTWAVE ENERGY OVER THE PACIFIC NORTHWEST THIS MORNING WILL SLIDE
TO THE NORTHERN PLAINS IN THE WNW FLOW ALOFT. SOUNDINGS SHOW A LOT
OF MID-UPR LEVEL MOISTURE WITH LIFT IN THAT MOIST LAYER BUT ONLY
SHALLOW DRY LOW-LEVELS BLO H9...WHICH SHOULD BE QUICKLY OVERCOME
SINCE THERE IS NO PERSISTENT FEED OF DRY AIR ADVECTION. RAMPED UP
POPS TO HIGH CHANCE AFT 09Z IN THE FAR WEST...WITH LIKELY POPS
ARRIVING AROUND DAYBREAK. MOST OF SOUNDING IS BLO 0C AND WARM AIR
ADVECTION IN LOW-LEVELS IS MEAGER...SO PROBABLY MOSTLY SNOW FOR
PTYPE EXCEPT IN LOWEST ELEVATIONS WHERE FREEZING LEVEL HEIGHT WILL
BE HIGH ENOUGH TO HAVE A MIX OF RAIN/SNOW. LOWS TONIGHT WILL BE IN
THE LOWER TO MIDDLE 30S.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 404 AM EDT WED OCT 29 2014

NAM SHOWS 850-500 MB Q-VECTOR CONVERGENCE AND DEEP MOISTURE 12Z TUE
THAT MOVES ACROSS THE CWA ON TUE AND BOTH MOVE OUT ON FRI. LAKE
EFFECT PCPN WILL BE THE WEATHER MAKER THIS FORECAST PERIOD WITH
TEMPERATURES COLD ENOUGH FOR RAIN AND SNOW. WITH THE COLDER AIR
ARRIVING...BUMPED UP THE SNOW RATIOS AND BECAUSE OF THIS...STORM
TOTAL SNOWFALL AMOUNTS FROM THU AFTERNOON TO FRIDAY EVENING RANGE
FROM AROUND 0.5 INCH IN THE SOUTHERN CWA UP TO 6 INCHES IN THE HURON
MOUNTAINS WHICH IS AN INCREASE FROM THE PREVIOUS FORECAST AND THE
TOTALS SEEM REASONABLE BASED ON THE COLD AIR COMING ACROSS LAKE
SUPERIOR AND THE NORTH TO NORTHEAST WIND DIRECTION. GFS AND NAM ARE
SHOWING 850 MB TEMPERATURES DROPPING TO -10C TO -12C THU NIGHT AND
WITH LAKE SUPERIOR TEMPERATURES RANGING FROM 6C TO 8C...THAT IS
ENOUGH LAKE-850 MB DELTA-T FOR LAKE EFFECT PCPN AND SNOW. DID NOT
MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR TEMPERATURES.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB RIDGE OVER THE PLAINS
12Z SAT WITH A SFC RIDGE OF HIGH PRESSURE OVER THE AREA. THE UPPER
RIDGE MOVES INTO THE UPPER GREAT LAKES 12Z SUN. A 500 MB TROUGH
MOVES INTO THE NORTHERN PLAINS 12Z MON AND THIS TROUGH MOVES INTO
THE UPPER GREAT LAKES 12Z TUE. A SFC COLD FRONT MOVES THROUGH THE
AREA MON NIGHT INTO TUE. FORECAST WILL START OUT DRY SAT INTO SUNDAY
AND THEN WILL HAVE SLIGHT CHANCE POPS FOR MON INTO TUE AS AN UPPER
LEVEL TROUGH APPROACHES. TEMPERATURES WILL START A WARMING TREND
THIS FORECAST PERIOD WITH TEMPERATURES APPROACHING NORMAL BY THE END
OF THE FORECAST PERIOD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 141 AM EDT WED OCT 29 2014

MOIST...CYCLONIC FLOW AROUND DEPARTING LOW PRES WILL WORK TO
MAINTAIN MVFR CONDITIONS AND OCNL -SHRA OVERNIGHT...ESPECIALLY AT
KIWD/KCMX. AS COLDER AIR ARRIVES THRU THE NIGHT...-SHRA WILL BECOME
MIXED WITH SNOW. CONDITIONS AT ALL TERMINALS SHOULD IMPROVE TO MVFR
MID TO LATE AFTN WITH GRADUAL ARRIVAL OF DRIER AIR ASSOCIATED WITH
APPROACHING SFC HIGH PRES RIDGE. HOWEVER...THERE IS SOME CONCERN
THAT LOWERING INVERSION MAY TRAP LINGERING CLOUDS BLO 3KFT INTO THE
EVENING HRS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 613 AM EDT WED OCT 29 2014

NORTHWEST WINDS 20-30 KTS IN WAKE OF A COLD FRONT WILL DIMINISH
STEADILY THROUGH THE DAY. COULD BE A FEW GALE GUSTS TO 35 KTS OVER
EASTERN SECTIONS THIS MORNING. LIGHT WINDS LESS THAN 20 KTS TONIGHT
INTO THURSDAY...THEN A STRONG COLD FRONT PASSING ON THURSDAY NIGHT
WILL USHER IN STRONG N-NE GALES OVER MUCH OF LK SUPERIOR INTO MUCH OF
THE DAY ON FRIDAY...LAST TO DIMINISH OVER EASTERN SECTIONS. A GALE
WATCH HAS BEEN POSTED FOR ALL OF LK SUPERIOR. WINDS DIMINISH LESS
THAN GALES BY FRIDAY EVENING AS HIGH PRESSURE BUILDS ACROSS THE AREA.
WINDS WILL FURTHER DIMINISH TO 25 KTS OR LESS FOR THE WEEKEND INTO
EARLY NEXT WEEK AS THE HIGH CROSSES THE REGION AND MOVES TO THE LOWER
GREAT LAKES BY MONDAY. &&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY AFTERNOON FOR
     LSZ249>251-266-267.

  GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
     LSZ162-240>242-263.

  GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY AFTERNOON FOR
     LSZ243>248-264-265.

LAKE MICHIGAN...
NONE.
&&

$$

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





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