Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 261906
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
306 PM EDT TUE AUG 26 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 305 PM EDT TUE AUG 26 2014

WV LOOP AND 12Z RAOBS INDICATE WSW FLOW ALOFT OVER THE UPPER GREAT
LAKES DOWNSTREAM OF TROUGH OVER THE WESTERN CONUS. PRIMARY COLD
FRONT SETTLING TO THE SOUTH AND EAST OF CWA IS ALLOWING FOR A MUCH
COOLER CANADIAN AIRMASS TO ADVECT OVER THE UPPER GREAT LAKES. H85
THERMAL TROUGH WITH TEMPS DOWN TO +5C ALONG WITH GUSTY ONSHORE WINDS
ARE KEEPING TEMPS NEAR LK SUPERIOR AROUND 60 DEGREES THIS AFTN WITH
READINGS TO NEAR 70 DEGREES FARTHER INLAND AND TOWARD DOWNSLOPING
NEAR LK MICHIGAN. A LOT OF LOW-MID CLOUDS DUE TO THE THERMAL TROUGH
HAVE ALSO HELD DOWN DAYTIME TEMPS SOME 15-20 DEGREES LOWER THAN WHAT
WAS OBSERVED ON MONDAY AFTN. PLAN FOR A PERSISTENCE FORECAST INTO
EARLY THIS EVENING...WITH DIMINISHING TREND FOR BOTH WINDS AND
CLOUDS.

UPSTREAM...WV LOOP SHOWS SHORTWAVE WITH DECENT DRYING IN ITS WAKE
OVER SOUTHERN SASKATCHEWAN. AS THIS WAVE MOVES EAST ACROSS LK
SUPERIOR LATER TONIGHT IT SHOULD DEEPEN SLIGHTLY. THE LIFT FM THE
WAVE ALONG WITH AN AREA OF MID-LEVEL CLOUDS TIED TO RIGHT ENTRANCE
REGION OF H3 JET STREAK FM ND TO LK SUPERIOR ARE FORECAST TO SYNC UP
OVERNIGHT TO POSSIBLY PRODUCE A FEW SHOWERS. PRIME NEGATIVE FACTOR
AS HIGHLIGHTED BY PREVIOUS SHIFT WILL BE DRY AIR BLO H9 THANKS TO
SFC RIDGE CENTERED OVER MINNESOTA. NAM/GFS AND GEM-REGIONAL SHOW
BEST MID-LEVEL MOISTURE MAINLY OVER WEST HALF OF CWA 06Z-12Z. GIVEN
DECENT UVM IN THE MOIST LAYER ALOFT...PUT A MENTION OF SPRINKLES IN
OVERNIGHT. SIGNIFICANT DRYING BEHIND SHORTWAVE PUTS KABOSH ON ANY
MOISTURE AND WEAK LIFT TOWARD 12Z OVER NW CWA AND BY 15Z ACROSS REST
OF CWA SO REALLY DECREASED CLOUD COVER INTO WEDNESDAY MORNING.
DESPITE SUNSHINE...PERSISTENT THERMAL TROUGHING WITH H85 TEMPS AS
LOW AS +4C OVER LK SUPERIOR SHOULD KEEP TEMPS IN THE 60S NORTH HALF
AND INTO THE LOWER 70S OVER THE SOUTH. LOWEST TEMPS...AROUND THE 60
DEGREE MARK...NEAR LK SUPERIOR FROM MUNISING TO GRAND MARAIS WITH
NORTH TO NORTHWEST ONSHORE WINDS.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 AM EDT TUE AUG 26 2014

LOWS WEDNESDAY NIGHT COULD GET CHILLY WITH THE LIGHT WINDS...CLEAR
SKIES...AND PWAT VALUES ABOUT 50 PERCENT OF NORMAL. TRENDED LOWS DOWN
INTO THE LOWER 40S OVER THE INTERIOR LOCATIONS...AND EVEN HAVE SOME
UPPER 30S FOR THE TRADITIONAL COLD RAWS SITES.

THE AREA OF HIGH PRESSURE WILL DRIFT TO THE EAST ON THURSDAY AS THE
FIRST OF A SERIES OF SHORTWAVES LIFTS NORTHEAST OUT OF THE CENTRAL
ROCKIES/PLAINS THURSDAY AFTERNOON INTO THURSDAY NIGHT. AS HAS BEEN
THE CASE FOR THE LAST COUPLE DAYS...SEEMS LIKE BEST OPPORTUNITY FOR
RAIN WILL BE OVER THE SOUTHEAST HALF OF THE CWA. THESE SHOWERS
COULD LINGER INTO FRIDAY OVER THE SAME AREA BEFORE THE NEXT WAVE
SLIDES NORTHEAST TOWARDS THE AREA ON FRIDAY NIGHT. ONCE
AGAIN...BEST CHANCES WILL BE OVER THE SOUTHEAST PART OF THE
AREA...BUT LIKELY MORE CONFINED TO NEAR THE LAKE MICHIGAN
SHORELINE. WHILE THAT WAVE IS MOVING THROUGH...A WEAK SURFACE
TROUGH WILL SLOWLY DROP SOUTHEAST ACROSS THE CWA ON SATURDAY. THINK
PRECIP CHANCES WITH THIS PASSING TROUGH WILL BE LIMITED DUE TO
SHALLOW MOISTURE AND LIMITED UPPER LEVEL SUPPORT...THUS WILL KEEP
POPS FOR MOST AREAS IN THE SLIGHT CHANCE CATEGORY. BEHIND THAT
TROUGH...A HIGH PRESSURE RIDGE WILL MOVE OVER THE CWA SATURDAY
NIGHT AND REMAIN THROUGH SUNDAY NIGHT...AS THE PARENT HIGH SLIDES
SOUTHEAST ACROSS NORTHERN ONTARIO.

A STRONGER UPPER TROUGH WILL APPROACH THE AREA FOR THE FIRST PART
OF NEXT WEEK. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS UPPER
TROUGH WILL BE MOVING THROUGH SOUTHERN CANADA AND ALLOW SOUTHERLY
FLOW TO INCREASE OVER THE AREA SUNDAY NIGHT INTO MONDAY. THIS WILL
LEAD TO ABOVE NORMAL TEMPERATURES ON MONDAY AHEAD OF THE COLD FRONT
THAT MOVES THROUGH MONDAY NIGHT INTO TUESDAY MORNING. WILL SHOW
INCREASING CHANCES FOR RAIN MONDAY INTO MONDAY NIGHT AS THE COLD
FRONT PASSES THROUGH.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 122 PM EDT TUE AUG 26 2014

THERMAL TROUGH ALOFT RESULTS IN BKN MVFR TO LOWER VFR CLOUDS THIS
AFTN AT KCMX AND KSAW. PLAN ON THESE CLOUDS TO SCATTER OUT BY THE
EVENING AS RIDGING TRIES TO WORK INTO THE AREA. MID-LEVEL CLOUDS
WILL INCREASE FOR A TIME OVERNIGHT UNTIL AROUND DAYBREAK ON WEDNESDAY
AS DISTURBANCE CROSSES THE REGION. GUSTY WEST WINDS AT KCMX SHOULD
DIMINISH QUICKLY BY LATE THIS AFTN. OTHERWISE...EXPECT LIGHT WINDS
REST OF THE TAF PERIOD AT ALL TERMINALS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EDT TUE AUG 26 2014

EXPECT WESTERLY WINDS AS HIGH AS 15-25KT OVER MUCH OF LAKE SUPERIOR
TODAY...RESULTING FROM PRES GRADIENT BTWN LOW PRES WELL OFF TO THE
NE AND HIGH PRES APPROACHING FROM THE W. AS THE HIGH SETTLES OVER
THE UPPER GREAT LAKES LATER TONIGHT THRU EARLY THU...WINDS WILL DROP
OFF TO MOSTLY UNDER 15KT. ALTHOUGH THE HIGH PRES DEPARTS THU...WINDS
SHOULD REMAIN UNDER 20KT FRI/SAT EVEN WITH TROF DROPPING ACROSS THE
AREA EARLY SAT.
&&

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

$$

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







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