Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 271140
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
740 AM EDT SAT SEP 27 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EDT SAT SEP 27 2014

...ANOTHER UNSEASONABLY WARM LATE SEPT DAY IS ON THE WAY TODAY...

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A STRONG RIDGE OVER MUCH
OF THE E HALF OF THE CONUS. CORE OF THE POSITIVE ANOMALIES WITH THE
RIDGE IS OVER NRN ONTARIO WHERE ANOMALIES ARE 2.5 STANDARD
DEVIATIONS ABOVE THE LONG TERM LATE SEPT AVG. WITHIN THE RIDGE...A
WEAK MID LEVEL LOW CENTERED ROUGHLY ALONG THE IA/MO BORDER IS
GENERATING ISOLD SHRA/TSRA OVER IA INTO SW MN. CLOSER TO HOME...THE
WEATHER REMAINS QUIET. TYPICAL FOR THIS TIME OF YEAR WITH THIS TYPE
OF WEATHER PATTERN THAT FEATURES QUIET/CLEAR NIGHTS...SHALLOW FOG
HAS AGAIN FORMED...MAINLY OVER SCNTRL AND ERN UPPER MI AND
ESPECIALLY NEAR RIVERS/LAKES/STREAMS.

WITH LITTLE OVERALL CHANGE IN AIR MASS TODAY COMPARED TO YESTEDAY...
TODAY WILL BE A CARBON COPY OF YESTERDAYS WEATHER. MIXING TO
AROUND 850MB SUPPORTS MAX TEMPS WELL INTO THE 70S TO THE LWR 80S
AWAY FROM LAKE MODERATION WHICH SHOULD BE CONFINED MAINLY TO AREAS
NEAR LAKE MICHIGAN. GIVEN THE SIMILAR AIR MASS CHARACTERISTICS...
SIMPLY USED YESTERDAYS OBSERVED MAX TEMPS FOR TODAYS FCST WITH A FEW
MINOR ADJUSTMENTS. DIURNAL TEMP RISE SHOULD BE NEARLY IDENTICAL TO
YESTERDAYS AS WELL...SO UTILIZED YESTERDAYS DIURNAL TEMP CURVE FOR
HOURLY TEMPS. SHALLOW FOG WILL QUICKLY DISSIPATE AFTER SUNRISE.

ANOTHER QUIET/CLEAR NIGHT IS EXPECTED TONIGHT. MIN TEMPS SHOULD BE A
LITTLE HIGHER THAN THIS MORNINGS MINS DUE TO SOME INCREASE IN
PRECIPITABLE WATER. SHALLOW FOG SHOULD MAKE ANOTHER APPEARANCE IN
GENERALLY THE SAME AREAS THAT IT HAS APPEARED IN RECENT NIGHTS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 354 AM EDT SAT SEP 27 2014

GOOD AGREEMENT IN OVERALL LOOK OF LARGER SCALE PATTERN INTO NEXT
WEEK. MAIN ISSUE REMAINS TIMING OF FRONT ON SUNDAY NIGHT INTO
MONDAY. ECMWF HAS STEADILY TRENDED TOWARD QUICKER FROPA ON SUNDAY
NIGHT WITH NNE WINDS OVER ALL OF UPR MICHIGAN BY 12Z MONDAY. NAM AND
GFS NOT AS AGGRESSIVE AND TREND FROM GFS IS MAINLY SLOWER...THOUGH
00Z RUN IS FARTHER SOUTH WITH FRONT BUT KEEPS MOST RAIN OUT OF CWA
UNTIL AFTER 12Z MONDAY. DIFFERENCES IN TIMING OF FROPA IS TIED TO
HOW MUCH JET ENERGY DIGS INTO BACKSIDE OF SHORTWAVE TROUGH CROSSING
NORTHERN ONTARIO. ECMWF SHOWS STRONGER JET/MORE AMPLFIED TROUGH
WHILE GFS AND GEM-NH SHOW MORE OF THE JET ENERGY AHEAD OF THE TROUGH
AND THUS A FLATTER MORE PROGRESSIVE TROUGH ALOFT. TOUGH TO SAY WHICH
IDEA IS RIGHT. MORE AMPLIED IDEA SEEMS GOOD AS MAIN SHORTWAVE
CURRENTLY OVER NORTHERN ALBERTA IS QUITE SHARP PER WV LOOP AND 00Z
RAOBS...BUT A MORE STRUNG OUT SHORTWAVE COULD ALSO OCCUR AS THE
RIDGE IT WILL BE DROPPING TOWARDS IS UNSEASONABLY STRONG WITH
590DAM HEIGHTS FM DAKOTAS OVER NORTHERN ONTARIO AND OVER SOUTHERN
QUEBEC AND LOWER GREAT LAKES.

CONSENSUS OF ALL MODELS AND THE CURRENT FORECAST POINTS TO FROPA LATE
SUNDAY NIGHT INTO MONDAY MORNING. WILL HEAD THIS WAY AS WELL. RESULT
WILL BE INCREASING RAIN CHANCES INTO MONDAY...LIKELY TURNING INTO
MORE OF A STRATIFORM RAIN BOOSTED BY H7-H5 Q-VECTOR CONVERGENCE WITH
THE SHORTWAVE AND ADDITIONAL LIFT WITHIN RIGHT ENTRANCE REGION OF JET
STREAK FM NORTHERN ONTARIO TO QUEBEC. SHALLOW COOL/MOIST FLOW
UPSLOPING INTO HIGHER TERRAIN NEAR LK SUPERIOR ONLY ADDS TO THE RAIN
CHANCES. TEMPS WILL EXHIBIT SHARP GRADIENT BTWN WHERE THE SUB H9 FLOW
IS STIFF ONSHORE AND WHERE MIXING TO H9 AND OFFSHORE WINDS WILL ALLOW
FOR TEMPS TO REACH NEAR 70 OVER THE SCNTRL. RAIN SHOULD DIMINISH TO
PROBABLY AREAS OF DRIZZLE LATER MONDAY NIGHT AS HIGH
PRESSURE/ANTICYCLONIC FLOW ADVANCES FURTHER INTO THE AREA. COOL TEMPS
PERSIST INTO TUESDAY...ESPECIALLY NEAR LK SUPERIOR WHERE WINDS STAY
ONSHORE ALL DAY.

RIDGING BUILDS BACK ALOFT BY WEDNESDAY AS TROUGHING EXPANDS OVER
WESTERN CONUS. WEDNESDAY WILL BE AN IN BTWN DAY AND COULD SEE AT
LEAST SOME SUNSHINE...AT LEAST IN THE EAST HALF. HIGH TEMPS WARMING
BACK INTO THE 60S AND POSSIBLY...WITH ENOUGH SUNSHINE...TOUCHING 70
DEGREES. LEADING SHORTWAVE EMERGING FM WEST CONUS TROUGH COULD BRING
SOME SHOWERS TO PARTS OF CWA BY WEDNESDAY EVENING. GREATEST CHANCES
OF RAIN LIKELY HOLD OFF TIL THURSDAY AS STRONGER FORCING ALOFT
COMBINES WITH MORE OF A LOW-LEVEL FRONTAL BOUNDARY. MODEL CONSISTENCY
IS SHAKY SO WILL NOT ALTER THE CONSENSUS POPS. INCLUDED SMALL CHANCES
FOR THUNDER ON THURSDAY AS THERE IS AT LEAST A BRIEF INTERLUDE OF
INSTABILITY WORKING ACROSS THE REGION AHEAD OF THE FRONT.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 739 AM EDT SAT SEP 27 2014

DRY AIR ASSOCIATED WITH HIGH PRES CENTERED NEAR LAKE HURON WILL
CONTINUE TO BRING PREVAILING VFR CONDITIONS TO KIWD/KCMX/KSAW THRU
THIS FCST PERIOD. HOWEVER...AS HAS BEEN THE CASE THE LAST FEW
NIGHTS...SHALLOW RADIATIONAL FOG WILL DEVELOP AT NIGHT AND AFFECT
KSAW. LIFR CONDITIONS EARLY THIS MORNING AT KSAW WILL QUICKLY
IMPROVE TO VFR WITHIN AN HR OR TWO OF SUNRISE. LOW-LEVEL WINDS
TONIGHT WILL HAVE MORE OF A DOWNSLOPE WESTERLY COMPONENT...SO AT
THIS POINT...NOT ANTICIPATING KSAW TO DROP BLO MVFR LATE TONIGHT.
THIS AFTN...GUSTY SSW WINDS WILL DEVELOP AT KIWD AND PERHAPS KSAW
WITH DAYTIME HEATING/MIXING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 AM 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.

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...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA





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