Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 170704
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
304 AM EDT WED SEP 17 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 409 PM EDT TUE SEP 16 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER WRN NAMERICA
AND A TROF OVER ERN NAMERICA. IN THE TROF...ONE SHORTWAVE IS MOVING
E OF JAMES BAY WITH SECOND JUST UPSTREAM IN FAR NRN ONTARIO. NW FLOW
ACROSS CNTRL CANADA IS SENDING THE NEXT SHORTWAVE SE INTO NRN
SASKATCHEWAN/NRN MANITOBA. AT THE SFC...COLD FRONT ASSOCIATED WITH
THE FIRST SHORTWAVE EXTENDS FROM SRN JAMES BAY TO JUST N OF LAKE
SUPERIOR TO FAR SRN MANITOBA. REGIONAL RADAR DISPLAY HAS SHOWN -SHRA
IN THE VCNTY OF THE COLD FRONT WITH PCPN AS FAR S AS NRN LAKE
SUPERIOR. PCPN HAS BEEN WEAKENING/DISSIPATING OVER THE LAST FEW HRS.
OVER UPPER MI...MOSTLY SUNNY SKIES HAVE ALLOWED TEMPS TO RISE TO 60
TO 70 THIS AFTN.

WHILE COLD FRONT TO THE N WILL CONTINUE TO DRIFT S AND THEN STALL
TONIGHT...IT WILL BE THE THIRD IN THE AFORMENTIONED TRIO OF
SHORTWAVES THAT WILL HELP PROPEL IT S THRU THE AREA ON WED. IN
RESPONSE TO THAT THIRD SHORTWAVE AND UNDER THE RIGHT ENTRANCE OF
UPPER JET OVER NRN ONTARIO/QUEBEC...A SUBTLE SFC WAVE IS ALSO
EXPECTED TO DEVELOP ALONG THE COLD FRONT AND TRACK ACROSS SOUTHERN
LAKE SUPERIOR OR UPPER MI VERY LATE TONIGHT THRU WED MORNING. A NICE
CORRESPONDING RIBBON OF LOW-LEVEL FRONTOGENESIS ALSO DEVELOPS.
SO...MODELS LOOK ON TRACK IN GENERATING A BAND OF -SHRA N OF COLD
FRONT AND PATH OF WEAK SFC WAVE TONIGHT/WED. UTILIZED A CONSENSUS OF
MODEL GUIDANCE IN PARTICULAR HIGHER RES MODELS TO CONSTRUCT PCPN
FCST FOR TONIGHT/WED IN ORDER TO MINIMIZE SLIGHT DIFFERENCES NOTED
IN COLD FRONT WHICH AFFECTS PCPN PLACEMENT. BASED ON LOCATION OF THE
STREAK OF FRONTOGENESIS...EXPECT MOST OF THE -SHRA TO PASS JUST N
AND E OF UPPER MI VERY LATE TONIGHT AND WED MORNING. SO...CHC POPS
WERE PAINTED ACROSS THE KEWEENAW AND ERN FCST AREA. OTHERWISE...
NOTHING MORE THAN SCHC POPS WERE USED.

TEMPS WED ARE TRICKY AS THERE WILL BE AN OPPORTUNITY FOR SOME
WARMING BEFORE FROPA. ACROSS THE N...FRONT SHOULD PASS EARLY ENOUGH
TO LIMIT MUCH WARMING. HIGHS OVER THE N SHOULD RANGE FROM THE UPPER
40S ACROSS THE TIP OF THE KEWEENAW TO MID 50S ELSEWHERE. AFTER
FROPA...TEMPS ACROSS THE N WILL LIKELY FALL INTO THE 40S IN THE
AFTN UNDER A BRISK NRLY WIND AND STRATUS DECK FOLLOWING FROPA.
ACROSS THE S...NUDGED HIGH TEMPS UP...TO AS HIGH AS THE UPPER 60S
FAR SCNTRL.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 303 AM EDT WED SEP 17 2014

NOT MUCH CHANGE IN THINKING FROM PREVIOUS SHIFT. THU WILL START WITH
LINGERING COLD AND FROST FROM WED NIGHT AS A 1025MB SFC HIGH WILL BE
CENTERED JUST NE OF THE CWA AT 12Z THU. THE HIGH WILL MOVE TO NEW
ENGLAND...WHILE STRENGTHENING TO 1030MB...BY 12Z FRI WHILE A SFC
TROUGH MOVES TO THE DAKOTAS. RETURN FLOW/WAA WILL JUST BE STARTING
LATE THU...SO DRY AIR LINGERING OVER THE REGION WILL MAKE FOR MOSTLY
SUNNY SKIES ON THU. TEMPS ON THU WILL TOP OUT IN THE MID TO UPPER
50S.

MOISTURE BEGINS TO INCREASE THU NIGHT AS THE RETURN FLOW
INCREASES...BUT MOST PRECIP LOOKS TO HOLD OFF UNTIL FRI WHEN AMPLE
MOISTURE WILL BE ESTABLISHED...A SERIES OF SHORTWAVE TROUGHS BEGINS
A TREK ACROSS THE AREA...AND THE PRESSURE GRADIENT/RETURN FLOW
INCREASES. MODELS ARE IN GOOD AGREEMENT ON THE START TIME OF PRECIP
FRI IN THE WAA REGIME...BUT HOW THINGS SHAPE UP ON FRIDAY AND
ESPECIALLY THE END TIME OF PRECIP ON SAT NIGHT OR SUN IS MORE
UNCERTAIN. EVEN THOUGH MODELS AGREE THAT THE STRONGEST SHORTWAVE
WILL ENTER THE REGION LATE SAT INTO SAT NIGHT...MODELS DISAGREE WITH
EACH OTHER AND FROM RUN TO RUN DUE TO THE COMPLEX NATURE OF PHASING
THE THREE WAVES OVER THE AREA. WILL LIKELY NOT HAVE GREATER
CERTAINTY ON END TIME OF PRECIP UNTIL CLOSER TO THE WEEKEND. HAVE
THE GREATEST POPS FROM LATE FRI THROUGH SAT. CONTINUED TO HAVE
CHANCES FOR THUNDERSTORMS LATE FRI INTO SAT NIGHT WHEN SOME ELEVATED
INSTABILITY IS EXPECTED...NO SEVERE WEATHER IS EXPECTED THOUGH.
850MB TEMPS WILL TOP OUT AROUND 15C FRI NIGHT INTO SAT...RESULTING
IN HIGH TEMPS IN THE MID 60S TO LOW 70S /WHICH IS AROUND AVERAGE/.
THE AIRMASS WILL BE COLDER SUN THROUGH TUE UNDER STRONGER NW FLOW
ALONG AND INCOMING SFC HIGH PRESSURE...RESULTING IN COOLER AND DRIER
CONDITIONS MON AND TUE.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 721 PM EDT TUE SEP 16 2014

VFR CONDITIONS WILL PREVAIL AT KIWD/KCMX/KSAW TONIGHT AS LOW LEVELS
REMAIN DRY. COLD FRONT CURRENTLY OVER ONTARIO WILL DROP S INTO
PORTIONS OF NRN UPPER MI TONIGHT BEFORE STALLING AS SUBTLE SFC LOW
PRES DEVELOPS AND TRACKS ESE ALONG FRONT TOWARD THE UPPER GREAT
LAKES. IT IS EXPECTED THAT LOW CLOUDS AND BAND OF RAIN THAT WILL
DEVELOP N OF FRONT WILL PASS JUST N OF KCMX LATE TONIGHT. AS THE
VERY WEAK SFC LOW PASSES WED MORNING...COLD FRONT WILL PUSH
S...BRINGING LOW MVFR CIGS TO ALL TERMINALS. IFR NOT OUT OF THE
QUESTION AT KCMX AND ESPECIALLY KSAW WHICH WILL SEE A MORE DIRECT
UPSLOPE WIND AFTER FROPA.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 PM EDT TUE SEP 16 2014

AHEAD OF AN APPROACHING COLD FRONT FROM THE N...SW WINDS AS HIGH AS
15-25KT THIS EVENING WILL FALL BACK TO GENERALLY 10-20KT TONIGHT AS
THE FRONT STALLS OVER THE AREA. FRONT WILL GET A PUSH S ON WED...AND
NE WINDS BEHIND THE FRONT WILL INCREASE TO 15-25KT FOR AT LEAST A
TIME. OVER FAR WRN LAKE SUPERIOR...COASTAL CONVERGENCE/FUNNELING
WILL PROBABLY RESULT IN WINDS AS HIGH AS 30KT LOCALLY. WINDS WILL
THEN DIMINISH TO UNDER 20KT WED NIGHT/THU AS HIGH PRES SETTLES OVER
NRN ONTARIO IN THE VCNTY OF LAKE SUPERIOR. AS THE HIGH THEN SHIFTS
TOWARD NEW ENGLAND AND A LOW PRES TROF APPROACHES FROM THE W...S
WINDS WILL INCREASE THU NIGHT/FRI. WITH S WINDS A MORE FAVORABLE
DIRECTION FOR STRONGER WINDS OVER ERN LAKE SUPERIOR THAN OVER THE
W...WINDS SHOULD REACH 20-30KT OVER THE ERN LAKE ON FRI. ALTHOUGH
WINDS WILL DIMINISH ON SAT AS THE TROF ARRIVES OVER THE UPPER
LAKES...W TO NW WINDS WILL AGAIN INCREASE TO AS HIGH AS 20-30KT
BEHIND THE TROF SAT NIGHT/SUN.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FROST ADVISORY FROM MIDNIGHT EDT /11 PM CDT/ TONIGHT TO 10 AM
     EDT /9 AM CDT/ THURSDAY FOR MIZ003-005>007-012>014-085.

  FREEZE WARNING FROM 11 PM EDT /10 PM CDT/ THIS EVENING TO 10 AM
     EDT /9 AM CDT/ THURSDAY FOR MIZ002-004-009>011-084.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...07
MARINE...ROLFSON





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