Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 280524
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
124 AM EDT SUN SEP 28 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 347 PM EDT SAT SEP 27 2014

...ONE MORE UNSEASONABLY WARM DAY IN STORE FOR SUNDAY...

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A STRONG RIDGE OVER MUCH
OF THE E HALF OF THE CONUS. 585-588 DECAMETER 5H HIGHS OVER THE UPPER
GREAT LAKES HAVE RESULTED IN INLAND HIGH TEMPS IN THE UPPER 70S TO
LOWER 80S ACROSS MUCH OF THE FORECAST AREA THIS AFTERNOON UNDER
MOSTLY SUNNY SKIES.

ANOTHER QUIET/CLEAR NIGHT IS EXPECTED TONIGHT UNDER THE INFLUENCE OF
THE HIGH PRESSURE RIDGE. MIN TEMPS SHOULD BE A LITTLE BIT HIGHER
THAN SATURDAY MORNINGS MINS DUE TO SOME INCREASE IN PRECIPITABLE
WATER. EXPECT MORE SHALLOW FOG FORMATION MAINLY WELL INLAND FROM
LAKE SUPERIOR. DOWNSLOPING SOUTHERLY WIND AND ASSOC MIXING SHOULD
GENERALLY PROHIBIT FOG FORMATION NEAR LAKE SUPERIOR.

EXPECT ONE MORE UNSEASONABLY WARM DAY ON SUNDAY. MIXING 850 MB OF
13-14C TO SFC SHOULD AGAIN YIELD HIGH TEMPS MAINLY IN THE UPPER 70S
AND LOWER 80S. ONSHORE SOUTH WINDS WILL RESULT IN COOLER TEMPS
AROUND 70S ALONG THE LAKE MI SHORELINE. KEPT IN SLIGHT CHC POPS FOR
SHRA OVER THE NCNTRL FCST AREA WHERE MODELS HINT THAT DEVELOPMENT OF
LAKE BREEZE OFF LAKE BREEZE COULD PROVIDE FOCUS FOR ISOLD
CONVECTION. MODIFIED NAM SOUNDINGS FOR 78/58 YIELD SBCAPE 200-300
J/KG WITH MINIMAL CIN.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 347 PM EDT SAT SEP 27 2014

A MORE ACTIVE AND TYPICAL FALL PATTERN WILL AFFECT THE AREA THROUGH
THE UPCOMING WEEK...WITH SIGNIFICANTLY COOLER WEATHER FOR MONDAY AND
EARLY NEXT WEEKEND.

SUNDAY NIGHT AND MONDAY...A SHORTWAVE TROUGH OVER MANITOBA WILL BE
INTERACTING WITH A RESIDUAL SFC TROUGH/COLD FRONT STRETCHING FROM
NORTH DAKOTA TO JUST NORTH OF LAKE SUPERIOR SUNDAY EVENING. MODEL
GUIDANCE HAD BEEN RATHER INCONSISTENT WITH THE STRENGTH AND TIMING
OF THE FRONT OVER THE PAST COUPLE DAYS...BUT SOME OF THE 12Z RUNS
TODAY APPEAR TO BE CONVERGING ON A SOLUTION. THE RECENT NAM AND GEM
RUNS ARE ADVERTISING A SHARPER TROUGH AXIS AND QUICKER PASSAGE MORE
IN LINE WITH THE ECMWF OVER THE PAST COUPLE DAYS. HAD ORIGINALLY
THOUGHT GUIDANCE WAS TRENDING SLOWER WITH YESTERDAYS RUNS...BUT AM
NOW MORE CONVINCED OF THE FASTER SOLUTION GIVEN THE ECMWF
PERSISTENCE. FRONTAL PASSAGE TIME LOOKS TO BE AROUND 00Z MONDAY
ALONG LAKE SUPERIOR. THE FRONT WILL CONTINUE SOUTHWARD THROUGH THE
NIGHT...CLEARING THE SOUTH CENTRAL AND EAST CWA SHORTLY AFTER 12Z
MONDAY.

ACTIVE LOW-LEVEL FGEN COMBINED WITH THE SHARP TROUGH AXIS WILL ALLOW
FOR DECENT PRECIP COVERAGE ALONG THE FRONT. THE ONE LIMITING FACTOR
TO MORE WIDESPREAD COVERAGE WILL BE LESSENING UPPER-LEVEL SUPPORT AS
THE RIGHT-ENTRANCE OF THE JET SHIFTS EASTWARD. THIS WILL KEEP THE
BEST COVERAGE ACROSS EASTERN LAKE SUPERIOR AND UPPER MI. ONLY MADE
SOME SMALL CHANGES TO THE POPS FOR MONDAY...KEEPING LIKELY POPS
CONFINED TO MAINLY THE NORTHEAST HALF OF THE CWA. IN THE MORNING AND
ALONG NE UPSLOPE AREAS OF LAKE SUPERIOR. BLUSTERY NE WINDS WILL
COMMENCE BEHIND THE FRONT ACROSS THE NORTH HALF. HIGHS TEMPS MONDAY
WILL BE IN THE MORNING FOR MUCH OF THE CWA....WITH TEMPS NORTHWEST
IN THE 40S AND SOUTHEST IN THE 50S BY THE AFTERNOON.

MONDAY NIGHT THROUGH TUESDAY NIGHT...THE FRONTAL PRECIP WILL CLEAR
THE CWA BY MONDAY EVENING WHILE MID-LEVEL RIDHING SHIFT ACROSS THE
UPPER GREAT LAKES AND A SFC HIGH BUILDS ACROSS NORTHERN ONTARIO AND
QUEBEC. THE AREA SHOULD REMAIN SOCKED IN WITH LOW CLOUDS THROUGH THE
NIGHT GIVEN PLENTY OF RESIDUAL LOW-LEVEL MOISTURE AND A DECENT
SUBSIDENCE INVERSION. CONTINUED NE UPSLOPE FLOW COMBINED WITH THE
MOISTURE WILL RESULT IN LINGER SHOWERS/DRIZZLE CENTRAL AND EAST
ALONG LAKE SUPERIOR THROUGH THE NIGHT. HOW LONG IT TAKES TO RID
THESE CLOUDS ON TUESDAY IS IN QUESTION. MORNING INVERSION
HEIGHTS OF 2-3KFT WILL TRAP REMAINING LOW-LEVEL MOISTURE BEFORE
MIXING AND THE ARRIVAL OF SOMEWHAT DRIER LOW-LEVEL AIR HELP ERODE
CLOUDS THROUGHOUT THE DAY. CLOUDS WOULD LIKELY REMAIN ACROSS THE
EAST LONGER GIVEN THE CLOSER PROXIMITY TO MOIST NE FLOW FROM THE
MOISTURE POOL.

WEDNESDAY THROUGH THURSDAY...DEEP TROUGHING OVER THE ROCKIES WILL BE
SHIFTING NORTHEASTWARD ACROSS THE NORTHERN PLAINS BY WEDNESDAY. A
LEAD SHORTWAVE WILL BE TRACKING ACROSS MANITOBA AS AN ASSOCIATED SFC
LOW SEND A COLD FRONT EASTWARD ACROSS THE UPPER MS VALLEY. THE FRONT
WILL BE ON THE DOORSTEP OF THE WESTERN CWA 12Z WEDNESDAY. WITH THE
MID-LEVEL RIDGE STILL OVER THE LOWER GREAT LAKES...INITIAL MID AND
UPPER-LEVEL SUPPORT WILL BE MARGINAL. THEREFORE...PRECIP COVERAGE
SHOULD BE MINIMAL WITH THE FRONT ON WEDNESDAY.

A QUICK-MOVING SHORTWAVE OVER BRITISH COLUMBIA WEDNESDAY WILL
REINFORCE THE DEEP TROUGH OVER THE NORTHERN PLAINS. COMBINED WITH
THE APPROACH OF THE RIGHT ENTRANCE OF AN UPPER JET AND INCREASING
LOW TO MID-LEVEL FGEN...THIS SHOULD ALLOW FOR A SUBSTANTIAL INCREASE
IN PRECIP COVERAGE ON THURSDAY AND THURSDAY NIGHT. THE ECMWF IS A
TOUCH SLOWER WITH THE TROUGH AND MORE WIDESPREAD WITH PRECIP THAN
THE GFS...BUT CONFIDENCE IS HIGH ENOUGH TO INTRODUCE LIKELY POPS
ACROSS THE WEST HALF THURSDAY AND THE EAST HALF THURSDAY NIGHT.

THURSDAY NIGHT THROUGH SATURDAY...MODEL SOLUTIONS DIVERGE AFTER
THURSDAY NIGHT AS THE GFS FORMS A STRONG LOW OVER LAKE HURON WHILE
THE ECMWF FORMS THE LOW CLOSER TO HUDSON BAY. EITHER WAY...THE
OVERALL PICTURE IS A SERIES OF RAW...CHILLY FALL DAYS BEGINNING ON
FRIDAY WITH BLUSTERY NW WINDS AND PLENTY OF WRAP-AROUND MOISTURE
BEHIND THE SYSTEM TO THE EAST. IN ADDITION...THE MID-LEVEL TROUGH
AXIS WILL REMAIN WEST OF THE AREA THROUGH FRIDAY...SO HAVE INCREASED
PRECIP CHANCES FOR FRIDAY. THIS IS ESPECIALLY TRUE ALONG LAKE
SUPERIOR WITH INCREASED LAKE MOISTURE AND UPSLOPE SUPPORT. THE
ARRIVAL OF 850 HPA TEMPS OF -3 TO -1C WILL SUPPORT SOME LAKE EFFECT
RAIN SHOWERS AS SFC-H8 DELTA T VALUES INCREASE TO AROUND 10C. THE
COOLEST WIDESPREAD TEMPS OF THE SEASON ARE ALSO EXPECTED AS HIGHS
STRUGGLE TO GET OUT OF THE 40S...A STARK DIFFERENCE FROM HIGHS IN
THE 70S THIS SATURDAY/TODAY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 122 AM EDT SUN SEP 28 2014

DRY AIR ASSOCIATED WITH HIGH PRES CENTERED OVER THE EASTERN GREAT
LAKES WILL CONTINUE TO BRING VFR CONDITIONS TO KIWD/KCMX/KSAW UNTIL
THIS EVENING. AS HAS BEEN THE CASE THE LAST FEW NIGHTS...SHALLOW
RADIATION FOG WILL DEVELOP AT NIGHT AND AFFECT KSAW. LOW-LEVEL WINDS
OVERNIGHT WILL HAVE MORE OF A DOWNSLOPE WESTERLY COMPONENT...SO AT THIS
POINT...NOT ANTICIPATING KSAW TO DROP BLO MVFR TOWARD DAYBREAK. A
COLD FRONT BOOSTED BY THE LAKE BREEZE WILL BRING VEERING WINDS LATE
THIS AFTERNOON AT CMX AND THIS EVENING AT SAW AND IWD. THERE IS SOME
UNCERTAINTY ON HOW QUICKLY THE FRONT WILL MOVE IN WITH LOWER MVFR
CLOUDS IN ITS WAKE. SOME SHOWERS MAY ALSO BE POSSIBLE ALONG THE LAKE
BREEZE BOUNDARY INTO N CNTRL UPPER MI LATE THIS AFTERNOON...BUT
CONFIDENCE ON ITS IMPACT AT SAW IS TOO LOW TO MENTION IN THE TAF.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 347 PM EDT SAT SEP 27 2014

LIGHT WINDS PERSIST THROUGH SUNDAY...THEN CHANGES ARE EXPECTED BY
MONDAY MORNING AS A FRONT WORKS NORTH TO SOUTH ACROSS LK SUPERIOR.
EXPECT WINDS TO SHIFT TO THE NORTHEAST AND QUICKLY RAMP UP TO 25-30
KTS AFTER MIDNIGHT SUNDAY NIGHT WITH STRONGER WINDS CONTINUING INTO
MIDDAY MONDAY. WINDS WILL DIMINISH MONDAY NIGHT INTO TUESDAY AS HIGH
PRESSURE SETTLES OVERHEAD. SOUTHEAST TO SOUTH WINDS INCREASE
WEDNESDAY INTO THURSDAY AHEAD OF THE NEXT LOW PRESSURE SYSTEM. WINDS
WILL BE STRONGEST OVER EASTERN HALF OF LK SUPERIOR. WHILE THERE IS
STILL UNCERTAINTY IN TIMING...AN EXTENDED NW GALE EVENT WILL BE
POSSIBLE SOMETIME FRIDAY INTO SATURDAY MORNING.

WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE SUPERIOR...
THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER MAINLY NORTHERN
PORTIONS OF LAKE SUPERIOR LATER TONIGHT THROUGH SUNDAY.
&&

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

$$

SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...JLB
MARINE...VOSS





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