Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 211106
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
706 AM EDT TUE APR 21 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 247 AM EDT TUE APR 21 2015

UPPER AIR PATTERN CONSISTS OF A 500 MB LOW OVER THE UPPER GREAT
LAKES EMBEDDED IN A TROUGH ACROSS THE GREAT LAKES REGION. THE 500 MB
LOW MOVES ACROSS THE U.P. AND LAKE SUPERIOR TODAY AND MOVES TO THE
EAST OF LAKE SUPERIOR TONIGHT.

NAM SHOWS SOME DEEPER MOISTURE AND 850-500 MB Q-VECTOR CONVERGENCE
MOVING THROUGH THE CWA TODAY AS THE 500 MB LOW MOVES PAST THE AREA.
THE MOISTURE REMAINS TONIGHT WHILE THE Q-VECTOR CONVERGENCE MOVES
OUT. GFS AND ECMWF SHOW THE SAME THING AS WELL.

BASICALLY...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST.
LOOKS LIKE THERE COULD BE SOME INSTABILITY SHOWERS TODAY WITH THE
UPPER LOW OVERHEAD AND ALSO A LAKE BREEZE CONTRIBUTION IN THE
EASTERN CWA WHICH WILL ENHANCE THE SHOWERS AND THIS WAS ALREADY
COVERED IN THE POPS. LOOKS LIKE A RAIN/SNOW MIX FOR TODAY AND THEN
SWITCHING OVER TO ALL SNOW TONIGHT. NORTHWEST LAKE EFFECT SNOW BELTS
WILL HAVE THE HIGHEST POPS FOR THIS FORECAST PERIOD AND THERE WILL
BE SOME ACCUMULATING SNOW ON THE GRASS THIS FORECAST PERIOD WITH 2
INCHES IN THE WEST FOR TODAY AND UP TO 3 INCHES TONIGHT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 429 AM EDT TUE APR 21 2015

COLD AIR WILL ALREADY LOCKED IN PLACE WILL NOT BE GOING FAR. AT 12Z
WEDNESDAY THE SFC LOW WILL BE SET UP FROM JAMES BAY THROUGH FAR E
ONTARIO...KEEPING NW WINDS OVER UPPER MI AND 850MB TEMPS HOVERING
AROUND -11C. THE 500MB LOW OVER THE E HALF OF ONTARIO WILL REMAIN IN
PLACE THROUGH AT LEAST THURSDAY MORNING. AS NOTED BY THE PREVIOUS
LONG TERM FORECASTER...WE WILL LIKELY BREAK THE RECORD LOW HIGH
TEMPERATURE AT NWS MQT ON WEDNESDAY (36 SET IN 1972).

THE 500MB LOW WILL BRIEFLY SHIFT OVER SE ONTARIO...CLOSER TO THE
STRENGTHENING SFC LOW OVER THE NEW ENGLAND STATES AND SE ONTARIO
THURSDAY AFTERNOON. LOOK FOR THE SFC/500MB LOW TO REMAIN IN PLACE
OVER S QUEBEC THROUGH EARLY SATURDAY. CLOSER TO HOME THIS WILL MEAN
THE CONTINUATION OF NW WINDS OFF THE NOW MOSTLY ICE FREE LAKE
SUPERIOR. 850MB TEMPS WILL RANGE FROM -8C TO -12C. SO DESPITE THE
LATE APRIL SUN...SNOW WILL BE THE DOMINANT WEATHER TYPE.

DIMINISHED THE CHANCE OF PRECIP A LITTLE QUICKER THAN WHAT WE
PREVIOUSLY HAD FOR THURSDAY NIGHT...SIDING MORE WITH THE LATEST
NAM/ECMWF. THE MAIN DISCREPANCY LOOKS TO BE RELATED TO THE EAST
COAST LOW THURSDAY. THE NAM/ECMWF KEEP THE LOW FARTHER TO THE
E...WHILE THE GFS SHIFTS IT MORE WESTWARD. THIS INHIBITS THE SFC
RIDGE AXIS FROM SET UP ACROSS CENTRAL CANADA FROM CROSSING INTO THE
UPPER GREAT LAKES THURSDAY NIGHT. THE ECMWF/NAM BRINGS THE RIDGE
IN...DISRUPTING THE NW WINDS NEAR THE SFC AND BRINGING WAA. WATCH
FOR LATER FCST CHANGES...AS THIS IS A LOWER CONFIDENCE PERIOD
THURSDAY EVENING INTO FRIDAY.

KEPT WITH A MAINLY DRY SOLUTION FRIDAY NIGHT THROUGH THE WEEKEND.
STILL A LITTLE CONCERNED ABOUT CONTINUING CLOUD COVER /IF NOT SNOW
SHOWERS/ E OF MUNISING ALONG LAKE SUPERIOR/. DID NOT FEEL CONFIDENT
ENOUGH TO GO HIGHER THAN SLIGHT CHANCE FOR POP E...AS THE 500MB
RIDGE BUILDS INTO THE UPPER GREAT LAKES AND THE SFC RIDGE CONTINUES
TO BUILD IN FROM CENTRAL CANADA. THE 21/00Z ECMWF EVEN SHOWS 850MB
TEMPS RETURNING TO 0C OR ABOVE SATURDAY NIGHT THROUGH THE END OF THE
FCST PERIOD...WHICH IS A BIT OPTIMISTIC COMPARED TO THE GFS. EITHER
WAY...SLOWLY MODERATING TEMPERATURES LOOK TO BE IN STORE FROM
SATURDAY /40S/ THROUGH MONDAY /MID 40S TO MID 50S/. THIS WILL STILL
BE BELOW NORMAL.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 706 AM EDT TUE APR 21 2015

IFR CONDITIONS WILL CONTINUE AT KIWD/KCMX THIS MORNING. AFTER THE
DISTURBANCE EXITS TO THE E...EXPECT MVFR CONDITIONS TO RETURN TO
KIWD/KCMX MID TO LATE MORNING. -SHSN WILL CONTINUE AT ALL TERMINALS
TODAY...AND IT`S CERTAINLY POSSIBLE THAT BRIEF IFR VIS COULD OCCUR
AT TIMES... ESPECIALLY AT KIWD/KSAW AS DAYTIME HEATING/INSTABILITY
AID -SHSN INTENSITY. WINDS WILL GENERALLY REMAIN
GUSTY...PARTICULARLY AT KCMX WHERE GUSTS OF 25-30KT SHOULD BE COMMON
FOR MUCH OF THE FCST PERIOD. MVFR CONDITIONS WILL CONTINUE
TONIGHT AT ALL TERMINALS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 247 AM EDT TUE APR 21 2015

A SHARP PRESSURE GRADIENT ON THE SW FLANK OF SLOW MOVING LOW
PRESSURE IN ONTARIO WILL CAUSE W TO NW WINDS UP TO 25-30 KTS INTO
THU. ALTHOUGH THERE COULD BE SOME GALE FORCE GUSTS AT
TIMES...WIDESPREAD GALES ARE NOT EXPECTED. THE CLOSER APPROACH OF HI
PRES LATER IN THE WEEK WILL RESULT IN LIGHTER WINDS FOR THE REST OF
THE FORECAST PERIOD.
&&

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

$$

SHORT TERM...07
LONG TERM...KF
AVIATION...07
MARINE...07


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