Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 251905
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
305 PM EDT TUE AUG 25 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM EDT TUE AUG 25 2015

00Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW UNSEASONABLY DEEP
CLOSED LO IN ONTARIO JUST NE OF LK SUP DRIFTING SLOWLY TO THE E...
WITH SHARP CYC FLOW ARND THIS FEATURE DOMINATING THE GREAT LKS.
LOCAL RAOBS INDICATE THE SFC-H7 LYR IS QUITE MOIST WITH H925...H85
AND H7 DEWPT DEPRESSIONS AT INL AND E NO MORE THAN A FEW DEGREES C.
THERE ARE ALSO TWO SHRTWVS OF NOTE ROTATING ARND THE LARGER SCALE
FEATURE. THE FIRST OF THESE IS NOW HEADING INTO NRN LK MI AT THE
BEGINNING OF THE SHIFT AND TAKING THE MORE WIDESPREAD SHOWERS THAT
HAD IMPACTED THE ERN CWA LAST EVNG TO THE SE WITH IT. IN THE WAKE OF
THIS DISTURBANCE...SFC OBS AND THE MQT 88D INDICATE RELATIVELY FEW
SHOWERS...MAINLY JUST SOME DRIZZLE...LINGER OVER UPR MI EARLY THIS
MRNG DESPITE THE MOIST LLVLS AND SHARP CYC NW FLOW. THE CULPRITS
APPEAR TO BE LARGER SCALE QVECTOR DVGC TO THE W OF THE CLOSED LO AND
BEHIND THE DEPARTING SHRTWV AND RATHER SHARP H875-85 INVRN SHOWN ON
THE 00Z INL/YPL RAOBS ASSOCIATED WITH THESE NEGATIVE DYNAMICS/HGT
RISES THAT IS LIMITING THE LK EFFECT COMPONENT TO THE NE OF H85
THERMAL TROF CENTERED ON AN AXIS FM INL TO GRB. 00Z H85 TEMPS WERE
3C AT INL AND GRB...BUT 10C AT YPL. WV IMAGERY/RAP ANALYSIS INDICATE
ANOTHER SHRTWV ROTATING SWD TO THE W OF THE CLOSED LO IS DROPPING
THRU NW ONTARIO. THE LATEST THUNDER BAY RADAR SHOWS AN AREA OF MORE
NMRS SHOWERS OVER LK NIPIGON MOVING INTO NRN LK SUP.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS ASSOCIATED SHRTWV
ROTATING SWD ARND SLOWLY DEPARTING CLOSED LO.

TODAY...WHILE ONTARIO SHRTWV MOVING TO THE S IS ON TRACK TO MOVE
INTO NRN LK SUP THIS MRNG...MODELS INDICATE DEEP LYR QVECTOR DVGC
AND HGT RISES...FCST TO BE ABOUT 50M BTWN 12Z-24Z TODAY...LEFT IN
THE WAKE OF THE CLOSED LO WL DOMINATE. SO ALTHOUGH FCST PROFILES
INDICATE SOME DEEPENING MSTR THRU THIS MRNG...THEY ALSO SHOW A NEAR
ABSENCE OF ANY UVV...IN FACT MAINLY LARGE SCALE SUBSIDENCE THAT WL
MAINTAIN THE INVRN NEAR H85 AND LIMIT POPS. THE ERN CWA HAS A BETTER
CHC TO SEE THE HIER POPS...AS THIS AREA WL BE CLOSER TO THE
DEPARTING DISTURBANCE/WEAKER SUBSIDENCE WITH AT LEAST SOME UVV/
SHARPER CYC FLOW AND DOWNSTREAM OF LK SUP IN PERSISTENT NW FLOW THAT
WL ACCENTUATE LLVL CNVGC. GIVEN THESE NEGATIVES...TENDED TO LOWER
GOING POPS. PLENTY OF LO CLDS WL LIMIT THE DIURNAL TEMP RECOVERY
AGAIN DESPITE SLOWLY MODERATING H85 TEMPS THAT WL ALLOW FOR A WARMER
DAY THAN YDAY. THE STEADY/GUSTY NW WINDS WL CONTINUE TO WHIP UP HI
WAVES ON LAKE SUP...RESULTING IN A HI SWIM RISK FOR MARQUETTE AND
ALGER COUNTIES.

TNGT...WITH CONTINUED SLOW HGT RISES/DEEP LYR QVECTOR DVGC/WEAKENING
LLVL CYC FLOW TO THE W OF WEAKENING CLOSED LO THAT IS FCST TO LIFT
NE TOWARD THE S END OF JAMES BAY BY 12Z WED...EXPECT DIMINISHING
POPS. THIS TREND WL BE MOST PRONOUNCED OVER THE W...WHERE THE LLVL
FLOW WL BECOME MORE ACYC CLOSER TO APRCHG SFC HI PRES MOVING INTO
MN. LINGERING LO CLDS WL LIMIT THE DIURNAL TEMP FALL. EXPECT THE
COOLEST OVERNGT LOWS TOWARD THE MID 40S OVER THE INTERIOR W...WHERE
THERE COULD BE SOME PARTIAL CLRG LATE WITH THE APRCH OF THE SFC HI
PRES.

.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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 128 PM EDT TUE AUG 25 2015

A NW FLOW OF COOL...MOIST AIR AROUND LOW PRES NE OF LAKE SUPERIOR
WILL BRING PREVAILING MVFR CONDITIONS TO KIWD/KCMX/KSAW THRU THE
AFTN. WINDS THIS AFTN WILL STILL BE GUSTY TO 20KT AT KSAW AND TO
25KT AT KCMX. OCNL -RA AND -DZ ARE POSSIBLE AT KCMX AND ESPECIALLY
KSAW THIS AFTN...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 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 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 AM EDT TUE AUG 25 2015

SHARP PRES GRADIENT ON THE WESTERN FLANK OF DEEP LO PRES MOVING THRU
ONTARIO TO THE E OF LAKE SUPERIOR WILL MAINTAIN NW WINDS UP TO 30
KTS TODAY. THE PASSAGE OF A DISTURBANCE THIS MORNING MAY CAUSE SOME
GALE FORCE GUSTS IN A CORRIDOR OVER THE CENTRAL LAKE. BUT AS THE LO
TO THE E WEAKENS AND MOVES TOWARD JAMES BAY TONIGHT...APPROACHING HI
PRES/WEAKENING PRES GRADIENT WILL CAUSE WINDS TO DIMINISH W-E. AS
THE HI MOVES OVER THE UPPER LAKES LATE WED/WED NIGHT...EXPECT WINDS
TO FALL UNDER 20 KTS. A RELATIVELY FLAT PRES GRADIENT WILL DOMINATE
LATE WEEK INTO THE WEEKEND...SO WINDS FOR THE MOST PART SHOULD BE
UNDER 20 KTS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...BEACH HAZARDS STATEMENT INTO THIS EVENING FOR
                 MIZ005-006.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.

&&

$$

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


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