Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 301146
AFDMQT

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

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 601 AM EDT THU OCT 30 2014

MAIN CONCERN FOCUSES ON POTENTIAL MODERATE LAKE EFFECT SNOW EVENT
FOR WEST AND NORTH CENTRAL UPPER MI TONIGHT INTO FRIDAY MORNING AS
VIGOROUS SHORTWAVE WEST OF HUDSON BAY DIGS SOUTH ACROSS THE UPPER
GREAT LAKES TONIGHT.

LATEST 09Z WATER VAPOR LOOP SHOWS A WEAKER SHORTWAVE MOVING SE
THROUGH ERN SD WHILE THE SHORTWAVE OF BIGGER CONCERN FOR OUR AREA IS
NOW LOCATED WEST OF HUDSON BAY. MAIN FORCING FROM SHORTWAVE OVER ERN
SD IS EXPECTED TO PASS WELL SOUTH OF THE AREA TODAY WITH ONLY WEAK
FORCING EXPECTED OVER OUR AREA FROM WEAK MID-LVL TROF OVERHEAD. AS A
RESULT EXPECT ONLY ISOLD SHRA...POSSIBLY A SNOW FLURRY THIS MORNING
ACROSS MUCH OF THE FCST AREA. FORCING WITH MODERATE TO STRONG Q-VECT
CONV WILL INCREASE THIS AFTERNOON ESPECIALLY LATE IN DAY AHEAD OF
HUDSON BAY SHORTWAVE WHICH WILL BE RAPIDLY DIVING SOUTH TOWARD THE
UPPER LAKES. COMBINATION OF FORCING AND ARRIVAL OF COLDER 8H TEMPS
OF -5 TO -6C IN WAKE OF FRONTAL PASSAGE WILL ALLOW SHRA/LAKE
ENAHNCED SHRA TO BECOME NUMEROUS OVER NW AND NCNTRL COUNTIES LATE IN
DAY AS WINDS SHIFT FM W TO NW.

TONIGHT...CONTINUED CAA IN WAKE OF FRONTAL PASSAGE WILL LOWER 8H
TEMPS TO -11C TO -12C AS NOTED ON MODELS. MODEL WET BULB ZERO
HEIGHTS AND CRITICAL 1000-850 MB THICKNESSES SUGGEST A QUICK
TRANSITION FM RAIN/SNOW MIX TO ALL SNOW BY EARLY EVENING IN
WEST...LATE EVENING CENTRAL AND EARLY OVERNIGHT EAST. MESOSCALE
MODEL AVERAGED QPF FROM .2-.4 IN WEST TO .3-.6 IN NCNTRL AND A
GENERAL 10-12/1 SNOW/WATER RATIO SHOULD YIELD 2-4 INCHES OVER THE
HIGHER TERRAIN OF WRN COUNTIES AND COULD YIELD 3 TO POSSIBLY 8
INCHES OVER THE HIGHER TERRAIN OF NCNTRL COUNTIES. MODERATE SNOW
SHOULD TAPER OFF QUICKER WEST AS FLOW BECOMES MORE ANTICYCLONIC LATE
TONIGHT BEHIND SHORTWAVE AND INVERSION HGTS BEGIN TO LOWER. THIS
SHOULD LIMIT ACCUMS IN WEST TO MARGINAL ADVISORY AMTS. FEEL MORE
CONFIDENT WITH ADVISORY AMOUNTS OVER BARAGA-MQT WHERE CYCLONIC
CONVERGENT LOW-LVL FLOW WILL LINGER LONGER AND FAVORABLE NRLY FETCH
SHOULD YIELD INLAND TOTAL SNOW AMTS SOLIDLY IN ADVISORY CATEGORY 4-7
BEFORE SNOW TAPER OFF FRI MORNING. WRN ALGER SHOULD ALSO SHOULD ALSO
SEE ADVISORY AMTS OF 4-5 INCHES ALTHOUGH SNOW WON`T LIKELY START
ACCUMULATING THERE UNTIL LATE TONIGHT. NRN DELTA COULD ALSO PUSH
ADVISORY AMTS DURING THE EVENT BUT DID NOT INCLUDE THEM IN AN
ADVISORY AT THIS TIME. HAVE ALL WEST AND NORTH CENTRAL COUNTIES
BORDERING LAKE SUPERIOR IN LAKE EFFECT SNOW ADVISORY TONIGHT INTO
FRIDAY MIDDAY.

NORTH WINDS GUSTING TO 45 MPH OR HIGHER ESPECIALLY ALONG THE LAKE
SUPERIOR SHORE MAY CAUSE SOME FLOODING OF LOW-LYING AREAS SO HAVE
ALSO ISSUED A LAKESHORE FLOOD ADVISORY LATE TONIGHT INTO EARLY
FRIDAY AFTERNOON FOR WEST AND NORTH CENTRAL UPPER MI. NORTH WINDS
GUSTING AT OR ABOVE 30 MPH JUST INLAND FM THE LAKE COULD ALSO CAUSE
SOME BLOWING OF SNOW AS WELL AND THIS IS MENTIONED IN THE WSW
STATEMENT.

.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 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 742 AM EDT THU OCT 30 2014

CIGS WILL REMAIN MVFR THROUGH MUCH OF TODAY WITH ISOLATED TO SCATTERED
RAIN SHOWERS AS AN UPPER DISTURBANCE MOVES THROUGH THE AREA. 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 THIS AFTN AND CONTINUE THROUGH TONIGHT.
THE AIR WILL BECOME COLD ENOUGH FOR THE PCPN TO CHANGE TO ALL SNOW BY
THIS EVENING. WHEN THIS OCCURS...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.

  LAKESHORE FLOOD ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 2 PM EDT /1
     PM CDT/ FRIDAY FOR MIZ001>006-009.

  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...VOSS
LONG TERM...07
AVIATION...VOSS
MARINE...07






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