Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 260739
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
339 AM EDT WED AUG 26 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 411 PM EDT TUE AUG 25 2015

LATEST WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A DEEP MID LEVEL
LOW CENTERED N OF GEORGIAN BAY DRIFTING EASTWARD. TO THE W...A RIDGE
EXTENDS FROM THE SRN ROCKIES N INTO SASKATCHEWAN/MANITOBA. IN THE
LINGERING MOIST...CYCLONIC FLOW AROUND THE MID LEVEL LOW...SOME
-SHRA/-DZ HAVE PERSISTED ACROSS THE FCST AREA TODAY...AIDED BY NW
UPSLOPE FLOW. THERE HAS PROBABLY BEEN SOME LAKE COMPONENT TO THE
PCPN AS WELL. WITH CLOUD TOPS WARMING OVER THE LAST SEVERAL HRS PER
IR IMAGERY...RADAR HAS SHOWN PCPN COVERAGE/INTENSITY DIMINISHING.
UNDER AN OVC CLOUD COVER...IT HAS BEEN ANOTHER UNSEASONABLY COOL DAY
FOR LATE AUG. SO FAR...TEMPS HAVE ONLY RISEN TO THE LOW/MID 50S IN
THE HIGHER TERRAIN AND WHERE PCPN LINGERS TO AROUND 60 OVER THE FAR
SCNTRL. BACK EDGE OF THE CLOUD COVER EXTENDS ROUGHLY FROM DULUTH TO
INTERNATIONAL FALLS AND NORTHWARD.

AS MID LEVEL LOW AND UPSTREAM RIDGE DRIFT E...EXPECT IMPROVING
CONDITIONS DURING THE SHORT TERM PORTION OF THE FCST. MAIN FCST
ISSUES WILL BE TIMING THE ENDING OF PCPN AND THE CLEARING TREND.
UNDER SLOW HEIGHT RISES/DEEP LAYER QVECTOR DIVERGENCE AND WEAKENING
CYCLONIC FLOW...LINGERING -SHRA/-DZ WILL CONTINUE TO DIMINISH
TONIGHT. THIS TREND WILL BE MOST PRONOUNCED OVER THE W...WHERE THE
LOW-LEVEL FLOW BECOMES MORE ANTICYCLONIC CLOSER TO APPROACHING SFC
HIGH PRES SETTLING OVER MN. LINGERING LOW CLOUDS WILL LIMIT TEMP
FALL TONIGHT. EXPECT THE LOWEST MINS (TOWARD THE MID 40S) OVER THE
INTERIOR W...WHERE THERE COULD BE SOME PARTIAL CLEARING LATE. IF
THERE IS SOME CLEARING...PATCHY FOG COULD DEVELOP.

A FEW -SHRA/PATCHY -DZ MAY CONTINUE TO LINGER INTO THE NCNTRL/ERN
FCST AREA WED MORNING UNDER ABUNDANT LOW-LEVEL MOISTURE. WITH
NEUTRAL TO VERY WEAKLY CYCLONIC LOW-LEVEL FLOW AND AIR MASS TOO WARM
FOR LAKE EFFECT PROCESSES...ANY PCPN WILL BE VERY LIGHT.
OTHERWISE...APPROACHING HIGH PRES WILL SETTLE OVER UPPER MI BY WED
EVENING. MODELS SUGGEST CLEARING WILL ONLY SLOWLY PUSH E ACROSS THE
FCST AREA AS THE HIGH ARRIVES AND THERMAL TROF DEPARTS. LARGELY
UTILIZED A MODEL CONSENSUS TO CONSTRUCT THE SKY COVER AND THE W TO E
CLEARING TREND ON WED. IT MAY NOT BE UNTIL TOWARD SUNSET THAT THE
LAST OF THE CLOUDS CLEAR THE ERN FCST AREA. UNDER INCREASING
SUNSHINE AND DEPARTURE OF THERMAL TROF...TEMPS WILL BEGIN TO
REBOUND. EXPECT HIGHS AROUND 60/LWR 60S E WHERE CLOUDS LINGER
LONGEST TO THE UPPER 60S TOWARD THE MI/WI BORDER.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 336 AM EDT WED AUG 26 2015

AFTER A PERIOD OF VERY COOL WX...LOOKS LIKE A RETURN OF MORE
SEASONABLE WX TO END THE WEEK. ALTHOUGH THERE MAY BE SOME SHOWERS
LATE THU NGT INTO SAT...PCPN CHCS APPEAR LIMITED BY THE PLACEMENT OF
UPR MI BTWN DISTURBANCES PASSING TO THE N AND S OF THE UPR LKS. A
RETURN OF SUMMER-LIKE WX APPEARS ON TAP NEXT WEEK AS AN UPR RDG IS
FCST TO BUILD OVER THE GREAT LKS DOWNSTREAM OF A DEEPENING TROF
ACROSS THE W.

THU...EXPECT A MOSUNNY AND WARMER DAY ON THU WITH HI PRES/ACYC SW
FLOW/DRY AIRMASS DOMINATING. H85 TEMPS REBOUNDING TO 12-14C BY LATE
IN THE DAY WL SUPPORT MAX TEMPS RISING WELL INTO THE 70S OVER MOST
OF THE CWA AWAY FM LK MI MODERATION.

THU NGT...UPR MI IS FCST TO BE SITUATED BTWN FAST WNW FLOW OVER SRN
CANADA AND A WEAKER SRN STREAM OVER THE CENTRAL CONUS. A DISTURBANCE
IN THE NRN STREAM IS FCST TO SLIDE ESEWD THRU ONTARIO DURING THE NGT
WITH ATTENDANT COLD FNT APRCHG NW LK SUP LATE. AT THE SAME TIME...A
SHRTWV IN THE SRN BRANCH WL BE DRIFTING SLOWLY ESEWD THRU THE MID/
UPR MS RIVER VALLEY. ALTHOUGH THE 12Z ECMWF GENERATED SOME SPOTTY
LGT PCPN OVER THE NW HALF OF UPR MI LATE AT NGT WITH THE RETURN OF
SOME HIER H85 THETA E AIR IN THE WLY FLOW TO THE S OF DISTURBANCE
PASSING THRU ONTARIO...AXIS OF WEAK FORCING/LINGERING LLVL ACYC FLOW
OVER UPR MI BTWN AREAS OF SHARPER DYNAMIC FORCING/CYC FLOW PASSING
TO THE S AND THE N AS WELL AS NOCTURNAL COOLING FAVOR THE DRIER
MODELS. SO CUT POPS TO NO HIER THAN LO CHC NEAR ISLE ROYALE CLOSER
TO APRCHG COLD FNT.

FRI THRU SAT...RECENT MODEL GUIDANCE HAS SHOWN SOME UNCERTAINTY ON
HOW FAR S COLD FNT ASSOCIATED WITH EXITING NRN BRANCH SHRTWV WL
REACH/BECOME STNRY AND ALSO ON TRACK OF SRN BRANCH DISTURBANCE/NRN
EDGE OF ACCOMPANYING PCPN SHIELD. GIVEN THE BLDG UPR RDG IN THE
PLAINS THAT WL FAVOR A MORE WNW FLOW ALOFT OVER THE UPR LKS...
SUSPECT THE 00Z ECMWF/18Z GFS SHOWING A FARTHER N PCPN AREA ARE OFF
THE MARK AND THAT THE FARTHER S TRACK OF THE SRN BRANCH DISTURBANCE
IS CORRECT WITH ACCOMPANYING PCPN REMAINING TO THE S OF UPR MI.
SEEMS THE BEST CHC FOR PCPN WL BE IF ANOTHER SHRTWV IN THE NRN
BRANCH FLOW OVER SCENTRAL CANADA DRIFTS CLOSE ENUF TO THE STNRY FNT
ALIGNED W-E SOMEWHERE IN THE UPR LKS TO TRIGGER SOME SHOWERS/PERHAPS
A TS OVER UPR MI. SINCE THE BULK OF THE MODELS SHOW THE SFC FNT
POSITIONED TO THE N OF THE CWA WITH LINGERING AXIS OF LLVL ACYC FLOW
OVER UPR MI...TENDED TO GO NO HIER THAN LO CHC POPS. WITH H85 TEMPS
WITHIN A FEW DEGREES OF 14C...EXPECT TEMPS TO AVG A BIT ABOVE NORMAL.

SAT NGT THRU TUE...BLDG UPR RDG DOWNSTREAM OF AMPLIFYING TROF OVER
WRN NAMERICA IS FCST TO DOMINATE THE GREAT LKS...BRINGING A PERIOD
OF DRY AND WARMER WX AS A LLVL ACYC SW FLOW ARND SFC HI PRES
CENTERED OVER THE MID ATLANTIC STATES PREVAILS. H85 TEMPS FCST TO
REACH 16-20C ON SUN AND THEN AOA 20C ON MON WL SUPPORT MAX TEMPS
WELL INTO THE 80S. ALTHOUGH SOME OF THE LONGER RANGE GUIDANCE HINTS
A COLD FNT ASSOCIATED WITH A SHRTWV RIDING OVER THE UPR RDG MAY
APRCH OR PASS NEXT TUE AND BRING SOME SHOWERS/TS AS EARLY AS LATE
MON...WL GO NO HIER THAN LO CHC POPS GIVEN THE EXPECTED STRENGTH OF
THE UPR RDG.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 121 AM EDT WED AUG 26 2015

A CONTINUED NW FLOW OF MOIST COOL AIR AROUND LOW PRES NE OF LAKE
SUPERIOR WILL ALLOW MVFR CONDITIONS TO PERSIST AT KIWD/KCMX/KSAW
THRU AT LEAST THE OVERNIGHT. EXPECT PATCHY -DZ AT KSAW INTO THE
MORNING HOURS...BUT SHOULDN`T REDUCE VIS BLO VFR. AS HIGH PRES
CONTINUES TO BUILD INTO THE AREA TODAY...MVFR CIGS WILL SCATTER OUT
AT KIWD/KCMX IN THE MORNING WHILE CLEARING WILL OCCUR LATER IN THE
AFTN AT KSAW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 411 PM EDT TUE AUG 25 2015

WITH LOW PRES NEAR JAMES BAY CONTINUING TO MOVE AWAY FROM THE AREA
AND HIGH PRES OVER THE PLAINS APPROACHING...WINDS WILL CONTINUE TO
DIMINISH ACROSS LAKE SUPERIOR FROM W TO E TONIGHT AND WED. WINDS
TONIGHT WILL GENERALLY RANGE FROM 10-20KT W TO 15-30KT E. WINDS ON
WED WILL DIMINISH TO UNDER 15KT W AND UNDER 20KT E BY THE END OF THE
AFTN. AS THE HIGH MOVES OVER THE UPPER LAKES WED NIGHT...WINDS WILL
BE UNDER 15KT ACROSS LAKE SUPERIOR. WINDS WILL BE MOSTLY UNDER 20KT
THU THRU SUN.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...KC
AVIATION...VOSS
MARINE...ROLFSON



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