Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 252333
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
733 PM EDT TUE AUG 25 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...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE AUG 25 2015

GOOD AGREEMENT IN OVERALL LOOK OF LARGE SCALE PATTERN INTO NEXT
WEEK. UPPER TROUGHING WITH SLOW MOVING SFC LOW REORGANIZES INTO
UPPER LOW OVER HUDSON BAY AND NUNAVUT CANADA BY END OF THE WEEK.
EXPECT UPPER RIDGE OVER PACIFIC NORTHWEST TO THE ROCKIES EARLY THIS
WEEK TO MOVE ACROSS THE PLAINS TO THE WESTERN GREAT LAKES BY THIS
WEEKEND AS TROUGHING DEEPENS AND SETTLES ACROSS WESTERN CANADA AND
THE PACIFIC NORTHWEST. CHANCES FOR MUCH RAINFALL IN THIS PATTERN ARE
SLIM.

STARTING WITH WEDNESDAY NIGHT...HIGH PRESSURE RIDGE SETTLES ACROSS
THE AREA SO WINDS WILL BECOME LIGHT. THE LIGHT WINDS AND PWATS DOWN
BLO 0.5 INCH SHOULD LEAD TO GOOD RADIATIONAL COOLING. LOWERED MINS
INTO THE MIDDLE 30S FOR TYPICAL COLD SPOTS OVER INTERIOR. SOUNDINGS
SHOW LOW-LEVEL MOISTENING AS WELL SO THERE MAY BE FOG. ALSO ADDED
MENTION OF FROST FOR COLDEST SPOTS. THIS NIGHT APPEARS TO BE TAIL
END OF THE FALL LIKE CONDITIONS BEFORE WARMING TREND STARTS UP ON
THURSDAY.

ONLY NOTABLE CHANCES OF RAIN WOULD BE LATE THURSDAY NIGHT INTO
FRIDAY AS WEAK COLD FRONT MAKES BRIEF PUSH ACROSS NORTHWEST ONTARIO
AND THE UPPER GREAT LAKES. LARGER SCALE SUPPORT NOT VERY STRONG FOR
RAIN OVER UPR MICHIGAN AS UPPER LEVEL SHORTWAVE ENERGY IS GENERALLY
DISPLACED OF UPPER LAKES WITH ONE STRONGER SHORTWAVE CROSSING WELL
TO THE NORTH OVER NORTHERN MANITOBA AND NORTHERN ONTARIO AND OTHER
STRONGER SHORTWAVE SLIDING FM WYOMING/NEBRASKA TO IOWA/NORTHERN
ILLINOIS. RESULT IS STRONGEST Q-VECTOR CONVERGENCE/LIFT STAYING OVER
NORTHERN ONTARIO AND FM SOUTHERN MINNESOTA TO WISCONSIN AND LOWER
MICHIGAN. APPEARS THAT GREATEST MOISTURE INFLOW IN FORM OF H85
THETA-E ADVECTION IS INTERCEPTED BY SOUTHERN SHORTWAVE. NO HELP FM
INSTABILITY WITH STRONGER MUCAPE STAYING OVER THE NORTHERN PLAINS
THURSDAY NIGHT INTO FRIDAY. BETTER SIGNAL FOR CONVECTION RUNS FM
SOUTHERN MINNESOTA TO SOUTHERN WISCONSIN CLOSER TO H85 MOISTURE
TRANSPORT. LOWER RANGE CHANCE POPS IS ALL THAT THIS FRONTAL BOUNDARY
WARRANTS ATTM FOR THURSDAY NIGHT INTO FRIDAY.

WEAKNESS IN THE UPPER LEVEL FLOW...VERY WEAK TROUGHING...LINGERS
OVER THE WESTERN GREAT LAKES ON SATURDAY. GFS SOUNDINGS SHOW NARROW
LAYER OF LOW-LEVEL MOISTURE BUT THIS IS PROBABLY NOT ENOUGH TO
SUPPORT SHOWERS. PROBABLY WILL BE SOME SORT OF ONSHORE COMPONENT TO
THE WINDS OVER THE EAST HALF OF CWA CLOSER TO HIGH PRESSURE OVER
MUCH OF THE GREAT LAKES. WEST HALF OF CWA SHOULD START TO SEE MORE
S/SW WINDS AHEAD OF DEVELOPING TROUGHING IN THE PLAINS. H85 TEMPS
COOL A FEW DEGREES COMPARED TO FRIDAY. WARMEST TEMPS ON SATURDAY IN
THE LOW-MID 70S SHOULD BE OVER THE WEST WITH LESS INFLUENCE OF GREAT
LAKES COOLING AND BETTER CHANCES OF SEEING SOME SUNSHINE. UPPER
LEVEL RIDGING TAKES BETTER HOLD ON SUNDAY. SFC WINDS REMAIN LIGHT AS
SFC RIDGE IS STILL CLOSE BY TO THE EAST. WITH H85 TEMPS WARMING TO
13-15C...SHOULD SEE READINGS MOST AREAS AT LEAST INTO THE UPPER 70S.
LOWER 80S OVER THE WEST WITH LESS LAKE INFLUENCE AND WARMER TEMPS
ALOFT.

RIDGING ALOFT FIRMLY OVERHEAD ON MONDAY WITH GRADIENT S WIND BTWN
HIGH PRESSURE OVER LOWER GREAT LAKES AND NEW ENGLAND AND A LOW
PRESSURE TROUGH OVER THE NORTHERN PLAINS. H85 TEMPS VARY WILDLY
THOUGH WITH THE ECMWF PUSHING BULK OF WARMTH CLOSER TO THE SFC
TROUGH AND OVER NORTHERN ONTARIO /H85 TEMPS UP TO 15C OVER UPR
MICHIGAN/ WHILE GFS SHOWS H85 TEMPS PUSHING PAST 22C ACROSS UPR
MICHIGAN. BLEND OF GUIDANCE AND SYNOPTIC SETUP ALONE JUSTIFIES
CONSENSUS TEMPS TO AT LEAST LOWER 80S. NOT A LOT OF CHANGE FOR
FIRST DAY OF SEPTEMBER WITH LINGERING UPPER RIDGE AND APPROACHING
SFC FRONT. GFS BRINGS FRONT THROUGH UPPER LAKES QUICKER...BUT EXPECT
SLOWER IDEA FM ECMWF GIVEN THE UPPER RIDGE IT WILL BE RUNNING UP
AGAINST. DRY WEATHER AND WARMING TEMPS ALOFT AHEAD OF FRONT WITH
STRONGER S/SW WINDS WILL GIVE MOST AREAS AWAY FM LK MICHIGAN SHORE A
GOOD CHANCE OF SEEING HIGHS INTO MIDDLE OR POSSIBLY UPPER 80S. LOWER TO
MIDDLE 80S WITH ONLY SLIGHT CHANCE POPS WILL DO FOR NOW.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 720 PM EDT TUE AUG 25 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 TONIGHT. PATCHY -DZ AND KSAW TONIGHT INTO EARLY WED...BUT
SHOULDN`T REDUCE VIS BLO VFR. APPROACHING HIGH PRES AND INFLUX OF
DRIER AIR MAY ALLOW CIGS TO RISE TO VFR AT KIWD FOR A BRIEF TIME
THIS EVENING BEFORE LOWERING SUBSIDENCE INVERSION BRINGS CIGS BACK TO
MVFR OVERNIGHT. AS HIGH PRES CONTINUES TO BUILD INTO THE AREA
WED...MVFR CIGS WILL SCATTER OUT AT KIWD/KCMX IN THE MORNING.
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...JLA
AVIATION...VOSS
MARINE...ROLFSON


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