Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 181138
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
738 AM EDT SAT OCT 18 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 443 AM EDT SAT OCT 18 2014

WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW AN UPPER TROUGH OVER THE
GREAT LAKES REGION...WITH MUCH OF THE MOISTURE ON WV IMAGERY
BEGINNING TO DIVE SOUTHEAST AND AWAY FROM THE AREA. AT THE
SURFACE...A 988MB LOW CENTERED OVER CENTRAL QUEBEC IS STRETCHING A
COLD FRONT SOUTHWEST INTO THE CENTRAL GREAT LAKES REGION. BEHIND
THIS COLD FRONT...STRONG NORTH-NORTHWEST WINDS ARE IN PLACE OVER
THE UPPER GREAT LAKES REGION WITH GUSTS TO 35KTS SEEN AT 2AM OVER
EASTERN LAKE SUPERIOR. THESE GUSTY WINDS HAVE HELPED AID UPSLOPE
ENHANCEMENT OF THE RAINFALL OVER THE AREA IN THE HIGHER TERRAIN OF
NORTH CENTRAL UPPER MICHIGAN. 24HR RAINFALL AMOUNT AT OUR OFFICE WAS
1.43 INCHES THROUGH 2AM...WHILE LOCATIONS NEAR THE LAKE SHORE IN
MARQUETTE COUNTY HAVE ONLY SEEN AROUND 0.9 INCHES. DID SEE SOME
SNOW MIX IN AT OUR OFFICE (STARTED SHORTLY AFTER 2AM) AND ALSO ON
SOME OF THE WESTERN U.P. WEBCAMS...WHICH MATCHES UP WITH MODEL
WETBULB0 VALUES. BUT...WITH DRIER AIR ALOFT ALREADY SURGING INTO
THE AREA...SEEN IN THE QUICK DIMINISHMENT OF RADAR RETURNS OVER THE
LAST 1-1.5HRS...DO HAVE SOME CONCERN WITH HOW MUCH SNOW WILL
CONTINUE TO MIX IN. THIS IS DUE TO THE STRENGTHENING INVERSION
AROUND 850MB BOTH TRAPPING IN MOISTURE BELOW IT AND ALSO LIMITING
THE TOP OF THE CLOUD TO AROUND -5 TO -7C. THIS IS MARGINAL FOR ICE
CRYSTALS TO BE IN THE CLOUDS AND ALTHOUGH THE WETBULB0 VALUES WOULD
SUPPORT MAINLY SNOW...WILL GO WITH A RAIN/SNOW MIX TO ACCOUNT FOR
THE UNCERTAINTY OF ICE CRYSTALS. HAVE BEEN IMPRESSED AT HOW QUICKLY
THE SHOWERS HAVE DIMINISHED WITH THE DEPARTING DEEP MOISTURE AND
THAT LEADS TO LIMITED CONFIDENCE ON HOW LONG THE
SCATTERED/ISOLATED SHOWERS WILL LINGER TODAY. WITH THE DEEP
MOISTURE GONE...FORCING COMES FROM LAKE SUPERIOR AND UPSLOPE. WITH
THE LAKE INFLUENCE LIMITED DUE TO LAKE SUPERIOR TEMPS AROUND 7C
(CREATING MARGINAL DELTA-T VALUES FOR PURE LAKE EFFECT)...WILL
FOCUS THE BEST POPS WHERE THE ADDED UPSLOPE INFLUENCE IS OVER
THE NORTH CENTRAL U.P. WILL DIMINISH PRECIPITATION CHANCES THROUGH
THE DAY AND HAVE THEM DONE BY MID/LATE AFTERNOON. ELSEWHERE...WILL
HOLD ON TO SOME CLOUD COVER INTO THE AFTERNOON WITH THAT MOISTURE
TRAPPED BELOW THE INVERSION...BUT EXPECT DIURNAL MIXING AND
INCREASING LOW LEVEL DRY AIR (FROM THE APPROACHING HIGH PRESSURE
RIDGE) TO HELP SCATTER THE CLOUDS OUT DURING THE AFTERNOON AWAY FROM
THE PERSISTENT NORTH-NORTHWESTERLY FLOW OFF LAKE SUPERIOR. THE
CLOUDS COMBINED WITH THE THERMAL TROUGH MOVING THROUGH THE AREA
WILL LEAD TO A COOL DAY TODAY AND HAVE HIGHS IN THE UPPER 30S AND
LOWER 40S.

WITH DECREASING CLOUDS AND THE CENTER OF THE HIGH MOVING DIRECTLY
OVER THE AREA TONIGHT...EXPECT A GOOD RADIATIONAL COOLING PERIOD
THIS EVENING AND FOR MUCH OF THE NIGHT OVER CENTRAL/EASTERN UPPER
MICHIGAN. THAT WILL LEAD TO A COLD AND FROSTY NIGHT FOR THE U.P.
AND WILL CONTINUE TO FOLLOW THE LOW END OF GUIDANCE FOR LOWS
TONIGHT. ONE THING TO KEEP AN EYE ON IS THE CLOUDS FOR THE NORTH
CENTRAL AND NORTHEAST CWA THIS EVENING AND INTO THE EARLY OVERNIGHT
HOURS. WITH THE NORTH-NORTHWEST WINDS CONTINUING TO PRODUCE SOME
LAKE INFLUENCE WITH THE MOISTURE TRAPPED BELOW THE
INVERSION...COULD SEE THE CLOUDS IN THOSE AREAS HANGING ON FOR MUCH
OF THE NIGHT. THUS...DID KEEP TEMPS A LITTLE HIGHER IN SOME OF
THOSE LOCATIONS FOR TONIGHT. FINALLY...HIGH CLOUDS WILL BE ON THE
INCREASE DURING THE OVERNIGHT HOURS AHEAD OF THE NEXT LOW MOVING
THROUGH ON SUNDAY NIGHT. THOSE HIGH CLOUDS AND RETURN FLOW
DEVELOPING BEHIND THE DEPARTING SURFACE HIGH MAY LEAD TO TEMPS
WARMING SLIGHTLY OVER THE WEST TOWARDS DAY BREAK.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 443 AM EDT SAT OCT 18 2014

SURFACE RIDGE AXIS OVER THE AREA EARLY SUNDAY WILL SHIFT INTO THE
EASTERN LAKES ON SUNDAY AS NEXT SHORTWAVE DROPS SOUTHEASTWARD OUT OF
CANADA INTO THE MEAN UPPER TROUGH POSITION OVER THE NORTHEAST U.S.
NOT AS MUCH MOISTURE IS AVAILABLE THIS TIME AROUND AND ONLY EXPECT
SCATTERED SHOWERS TO ACCOMPANY THE SURFACE/UPPER TROUGH PASSAGE LATE
SUNDAY INTO EARLY MONDAY.

BEYOND MONDAY...A MUCH NEEDED BREAK FROM THE WET WEATHER IS ON THE
WAY. UPPER RIDGING OVER THE CENTRAL PLAINS WILL NUDGE JUST FAR
ENOUGH EAST INTO THE UPPER GREAT LAKES ALLOWING FOR A STRING OF DRY
AND MILD DAYS FOR THE TUESDAY THROUGH THE END OF THE WORK WEEK
PERIOD.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 738 AM EDT SAT OCT 18 2014

COLD AIR AND ABUNDANT LOW LEVEL MOISTURE BEHIND THE SYSTEM THAT
MOVED THROUGH THE AREA YESTERDAY WILL CONTINUE TO BRING MVFR
CEILINGS TO THE THREE TAF SITES FOR THE FIRST HALF OF THE DAY.
THEN...DRIER AIR FROM A HIGH PRESSURE RIDGE MOVING INTO THE AREA
WILL LEAD TO DECREASING CLOUDS THIS AFTERNOON/EVENING AND A MOSTLY
CLEAR NIGHT TONIGHT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT SAT OCT 18 2014

A LOW SPINNING OVER CENTRAL QUEBEC WILL CONTINUE TO SLIDE A COLD
FRONT EAST ACROSS THE CENTRAL AND LOWER GREAT LAKES THIS MORNING.
AS THIS OCCURS...AN AREA OF HIGH PRESSURE WILL MOVE OVER THE UPPER
GREAT LAKES TODAY AND LEAD TO QUICKLY DIMINISHING WINDS ACROSS LAKE
SUPERIOR. WILL CONTINUE THE GALE WARNINGS OVER THE EASTERN LAKE
WITH STILL A FEW GALE FORCE GUSTS OCCURRING...BUT IT SHOULD
DIMINISH BELOW GALES AFTER SUNRISE. EXPECT WINDS TO STAY BELOW 25KTS
FOR THE REST OF THE FORECAST PERIOD.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ249>251-266-267.

LAKE MICHIGAN...
  GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LMZ221-248-250.

&&

$$

SHORT TERM...SRF
LONG TERM...MZ
AVIATION...SRF
MARINE...SRF






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