Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 300829
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
429 AM EDT THU OCT 30 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 324 PM EDT WED OCT 29 2014

A 991MB SURFACE LOW TO THE NORTHEAST OF JAMES BAY IN NORTHERN
QUEBEC SWEPT A SURFACE TROUGH ACROSS THE UPPER GREAT LAKES REGION
LAST NIGHT. THIS HAS LED TO A POCKET OF COLD AIR AT 850MB (AROUND
-5C) TO HELP PRODUCE SOME LAKE EFFECT RAIN/SNOW SHOWERS THIS PAST
MORNING. ALTHOUGH ABUNDANT LOW LEVEL MOISTURE CAN BE SEEN WITH THE
LOW CLOUDS OVER MUCH OF THE UPPER GREAT LAKES REGION...DRYING ALOFT
IN ASSOCIATED WITH THE APPROACHING UPPER/SURFACE RIDGE HAS LED TO
THE CLOUDS TOPS QUICKLY LOWERING THIS MORNING FROM 8KFT TO 5KFT BY
14Z. THIS HAS STAYED STEADY THROUGH THE AFTERNOON AND IS HELPING TO
LIMIT THE STRENGTH OF THE SHOWERS OVER NORTHCENTRAL AND NORTHEAST
UPPER MICHIGAN UNDER THE NORTHWESTERLY FLOW OFF LAKE SUPERIOR. WILL
CONTINUE TO SHOW A GRADUAL DIMINISHING TREND IN THAT AREA THIS
EVENING WITH THE TEMPERATURES ALOFT SLIGHTLY WARMING AND REDUCING
THE OVER LAKE INSTABILITY. OVER THE WEST...THE BACKING WINDS WITH
THE HIGH PRESSURE RIDGE (FROM A HIGH MOVING OUT OF THE MID
MISSISSIPPI VALLEY) AND THE INCREASED SUBSIDENCE HAS DIMINISHED THE
SHOWERS (WEBCAMS INDICATING PAVEMENT DRYING)...BUT ANOTHER AREA OF
LOW CLOUDS MOVING EAST INTO THE AREA WILL KEEP MUCH OF THAT AREA
CLOUDY TONIGHT. OVER THE CENTRAL AND EAST AWAY FROM LAKE
SUPERIOR...THERE IS THE POTENTIAL OF THE CLOUD COVER SCATTERING OR
EVEN CLEARING OUT FOR A PERIOD AFTER DIURNAL HEATING IS LOST. DID
TRY TO SHOW A QUICK PERIOD OF PARTLY-MOSTLY CLOUDY SKIES IN THAT
AREA THIS EVENING BEFORE THE LOW CLOUDS SLIDE BACK IN.

FOR THE REST OF TONIGHT INTO THURSDAY...THERE ARE A COUPLE
SHORTWAVES THAT WILL BE APPROACHING THE NORTH CENTRAL CONUS. THE
FIRST ONE IS CURRENTLY ROUNDING THE WEAK UPPER RIDGE IN THE DAKOTAS
AND WILL DIVE SOUTHEAST OF THE AREA. A WEAK SURFACE LOW DEVELOPING
ALONG THIS SHORTWAVE WILL STRETCH A WEAK TROUGH NORTH ACROSS THE
UPPER GREAT LAKES LATE TONIGHT AND INTO THURSDAY. WHILE THERE WILL
BE PLENTY OF MOISTURE AS THIS WEAK UPPER TROUGH SLIDES THROUGH THE
AREA...THE FORCING IS FAIRLY LIMITED AND LIQUID AMOUNTS SHOULD
GENERALLY STAY BELOW 0.20 INCH. THE GREATEST AMOUNTS WILL BE OVER
THE NORTHWEST PART OF UPPER MICHIGAN...WHERE THE COMBINATION OF
BACKING WESTERLY TO NORTHWESTERLY FLOW OFF THE LAKE AND INCREASING
LOW LEVEL CONVERGENCE BEHIND THE TROUGH/LOW IN THE AFTERNOON WILL
SUPPORT HIGHER AMOUNTS AND A LITTLE BETTER COVERAGE IN THE SHOWERS.
ALTHOUGH THE LOWERING OF THE CLOUD TOPS CREATES SOME CONCERN ON THE
POTENTIAL FOR ICE CRYSTALS IN THE CLOUD THIS AFTERNOON AND
EVENING...WILL CONTINUE TO MENTION SOME POTENTIAL OF SNOW DUE TO THE
STRONGER SHOWERS LIKELY RISING A LITTLE HIGHER AND INTO COLDER
TEMPERATURES. OTHERWISE...ONCE THE DEEP MOISTURE ARRIVES LATE
TONIGHT WITH THE WEAK SHORTWAVE EXPECT PLENTY OF ICE CRYSTALS IN THE
CLOUD AND THE PRECIP TYPE DEPENDS ON THE NEAR SURFACE TEMPERATURES.
WETBULB0 VALUES HAVE BEEN HANDLING THESE EVENTS WELL OVER THE LAST
MONTH AND WILL CONTINUE TO LEAN ON THAT FOR THE RAIN/SNOW FORECAST
THROUGH TOMORROW. MODELS INDICATING WETBULB0 VALUES BETWEEN
900-2100FT SO WILL GO WITH RAIN/SNOW (OVER THE HIGHER TERRAIN) TO
MAINLY RAIN OVER THE AREA TONIGHT INTO THURSDAY AFTERNOON. THEN AS
THE COLDER AIR STARTS SURGING IN LATE IN THE AFTERNOON INTO
THURSDAY EVENING...SHOULD SEE A QUICK TRANSITION TO ALL SNOW. A
SECONDARY AND STRONGER SHORTWAVE DIVING SOUTH-SOUTHEAST ACROSS
MANITOBA AND NORTHWEST ONTARIO ON THURSDAY WILL BE JUST TO THE
NORTHWEST OF LAKE SUPERIOR AT 00Z ON FRIDAY. THIS FEATURES WILL
DRIVE THE WINTER-LIKE WEATHER FOR THURSDAY NIGHT INTO FRIDAY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 429 AM EDT THU OCT 30 2014

NAM SHOWS A DEEP TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A
STRONG 500 MB RIDGE OVER THE ROCKIES. THE TROUGH DIGS INTO THE
EASTERN U.S. ON FRI WHILE THE RIDGE MOVES INTO THE PLAINS. THE RIDGE
THEN REMAINS IN THE PLAINS THROUGH SAT NIGHT WITH THE DEEP TROUGH
MOVING TO THE ERN SEABOARD.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST THIS PERIOD.
TEMPERATURES SEEMED REASONABLE AND LEFT THEM ALONE. NAM AND GFS SHOW
850MB TEMPERATURES DOWN TO -10C TO -12C 12Z FRI WARMING TO -2C TO
-6C BY 12Z SAT AND WITH LAKE SUPERIOR TEMPERATURES FROM 6C TO
8C...THIS IS ENOUGH ON FRI AND FRI EVENING TO GET LAKE EFFECT SNOW
SHOWERS. NORTHERLY LAKE EFFECT SNOW BELTS WILL SEE UP TO 2 INCHES OF
SNOW ON FRIDAY. SFC HIGH PRESSURE WILL BUILD IN QUICKLY AND LAKE
EFFECT SNOW SHOWERS LOOK TO HANG ON INTO FRI NIGHT WITH SLOWLY
DIMINISHING POPS FRI AND FRI NIGHT. SAT AND SAT NIGHT LOOK DRY FOR
NOW WITH FURTHER MODIFICATION IN THE AIRMASS AND TEMPERATURES
WARMING ENOUGH TO GET RID OF LAKE EFFECT CLOUDS...SO SHOULD SEE
DECREASING CLOUDS SAT AND SAT NIGHT.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
WESTERN U.S. AND A RIDGE OVER THE CENTRAL U.S. 12Z SUN. THE RIDGE
MOVES TO THE LOWER GREAT LAKES ON MON. THE TROUGH PUSHES INTO THE
UPPER GREAT LAKES LATE MON INTO TUE MORNING. MORE UPPER TROUGHING
COMES IN FOR WED. IT WILL START OFF DRY FOR SUN AND SUN NIGHT AND
THEN WET THROUGH WED WITH THE BEST CHANCE FOR PCPN MON NIGHT AND
TUE. TEMPERATURES WILL STAY NEAR NORMAL THIS FORECAST PERIOD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1256 AM EDT THU OCT 30 2014

CIGS WILL GENERALLY REMAIN MVFR OVERNIGHT. SCATTERED RAIN SHOWERS
WILL MOVE INTO THE AREA LATER TONIGHT INTO THU MORNING AS AN UPPER
DISTURBANCE MOVES THROUGH THE AREA...BUT CIGS/VSBYS SHOULD REMAIN
MVFR. HOWEVER...BEHIND THIS DISTURBANCE...MUCH COLDER AIR WILL
GRADUALLY FILTER INTO THE AREA. MEANWHILE...ANOTHER LOW PRESSURE
SYSTEM WILL DEVELOP SOUTHEAST OF THE AREA ALLOWING WINDS TO TURN
NORTHERLY OFF THE LAKE. THE COMBINATION OF THE COLD AIR AND
NORTHERLY WINDS WILL ALLOW LAKE EFFECT PCPN TO DEVELOP LATE THU AFTN
AND CONTINUE INTO THU NIGHT. THE AIR WILL BECOME COLD ENOUGH FOR THE
PCPN TO CHANGE TO ALL SNOW. WHEN THIS OCCURS /MOST LIKELY AFTER 03Z
FRI/...EXPECT VSBYS TO DROP TO IFR FOR AT LEAST SAW AND POSSIBLY
IWD AND CMX. LOOKS LIKE THE SNOW WILL CONTINUE INTO FRI MORNING AT
LEAST AND THE NORTHERLY WINDS WILL GRADUALLY BECOME STRONGER INTO
FRIDAY MORNING WITH GUSTS ABOVE 30 KT NOT OUT OF THE QUESTION.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 AM EDT THU OCT 30 2014

A WEAK LOW PRESSURE SYSTEM MOVING ACROSS UPPER MICHIGAN THURSDAY
AFTERNOON WILL STRENGTHEN AS IT MOVES SOUTHEAST THROUGH THE REST OF
THE GREAT LAKES TONIGHT INTO FRIDAY. THAT LOW...IN COMBINATION WITH
A STRONG HIGH IN CENTRAL CANADA AND THE NORTHERN PLAINS WILL LEAD TO
STRONG NORTHERLY FLOW ACROSS LAKE SUPERIOR. AT THE PRESENT
TIME...EXPECT GALES UP TO 45KTS TONIGHT INTO FRIDAY MORNING AND WILL
UPGRADE TO A GALE WARNING FOR ALL OF LAKE SUPERIOR. THE GALES WILL
COME TO AN END ON FRIDAY AFTERNOON AS THE HIGH PRESSURE RIDGE BUILDS
OVER THE AREA. THIS WILL LEAD TO WINDS DIMINISHING BELOW 20KTS ON
FRIDAY NIGHT AND CONTINUING INTO SATURDAY EVENING. AS THE HIGH
DEPARTS AND ANOTHER LOW DEVELOPS IN THE NORTHERN PLAINS...SOUTHERLY
FLOW WILL DEVELOP OVER LAKE SUPERIOR ON SATURDAY NIGHT (WINDS UP TO
25KTS) AND CONTINUE INTO MONDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY FROM 8 PM EDT /7 PM CDT/ THIS EVENING
     TO NOON EDT /11 AM CDT/ FRIDAY FOR MIZ001>003-009-084.

  LAKE EFFECT SNOW ADVISORY FROM 8 PM THIS EVENING TO 2 PM EDT
     FRIDAY FOR MIZ004>006.

LAKE SUPERIOR...
  GALE WARNING FROM 11 PM THIS EVENING TO 2 PM EDT FRIDAY FOR
     LSZ249>251-266-267.

  GALE WARNING FROM 10 PM THIS EVENING TO 11 AM EDT FRIDAY FOR
     LSZ243>248-264-265.

  GALE WARNING FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO 8 AM EDT
     /7 AM CDT/ FRIDAY FOR LSZ162-240>242-263.

LAKE MICHIGAN...
  GALE WARNING FROM 4 AM TO 5 PM EDT FRIDAY FOR LMZ221-248-250.

&&

$$

SHORT TERM...SRF
LONG TERM...07
AVIATION...MRD
MARINE...07






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