Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 020522
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
122 AM EDT TUE SEP 2 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 308 PM EDT MON SEP 1 2014

UPPER AIR PATTERN CONSISTS OF A BROAD 500 MB TROUGH OVER THE
NORTHERN ROCKIES TO THE UPPER GREAT LAKES WITH A NEGATIVE TILTED
SHORTWAVE OVER THE UPPER MISSISSIPPI RIVER VALLEY. THE SHORTWAVE
PASSES THROUGH THIS AFTERNOON AND THE UPPER TROUGH PASSES THROUGH ON
TUE. DEEPER MOISTURE AND DYNAMICS LEAVE THE AREA TONIGHT.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT SPED UP
EXIT OF POPS FOR LATE THIS AFTERNOON AND TONIGHT AND DELAYED POPS
FOR EARLY TUE MORNING UNTIL THE MID MORNING. LOOKED LIKE THERE BE
ENOUGH INSTABILITY WITH SOME HEATING AND STILL BEING IN THE UPPER
TROUGH TO HAVE SOME POPS FOR LATE TUE MORNING INTO TUE AFTERNOON
WITH SOME DIURNAL INSTABILITY SHOWERS POSSIBLE.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 338 PM EDT MON SEP 1 2014

AN ACTIVE MID-RANGE FORECAST AHEAD WITH A STRONG EARLY-FALL SYSTEM
TRACKING ACROSS THE REGION WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.
HEAVY RAINFALL IS POSSIBLE FOR WESTERN UPPER MI WEDNESDAY
NIGHT...FOLLOWED BY A VERY CONDITIONAL CHANCE FOR STRONG STORMS
THURSDAY AFTERNOON. SEASONABLY COOL TEMPS THEN ARRIVE BY THE END OF
THE WEEK.

TUESDAY NIGHT AND WEDNESDAY MORNING...A WEAK MID-LEVEL SHORTWAVE
TROUGH WILL BE EXITING TO THE EAST AT THE BEGINNING OF THE
PERIOD...WITH ZONAL FLOW DEVELOPING ACROSS THE NORTH CENTRAL CONUS.
A WEAK SHORTWAVE TROUGH CURRENTLY OVER NORTHWEST ALBERTA IS PROGGED
TO TRACK ACROSS NORTHERN ONTARIO LATE TUESDAY NIGHT INTO
WEDNESDAY...CLIPPING THE CWA. MEANWHILE...A DEEP TROUGH DEVELOPING
OVER ALBERTA WEDNESDAY WILL BE INDUCING A BROAD SFC LOW OVER THE
NORTHERN AND CENTRAL HIGH PLAINS. LOW-LEVEL MOISTURE WILL BE SURGING
NORTHWARD AHEAD OF THIS TROUGH. HOWEVER...THE ARRIVAL OF THIS
MOISTURE ALONG A WARM FRONT SOUTHWEST OF THE REGION WEDNESDAY DOES
NOT LINE UP WELL WITH THE WEAK TROUGH PASSAGE. ISOLATED SHOWERS ARE
POSSIBLE ACROSS LAKE SUPERIOR LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING...BUT A RATHER DRY SUB-CLOUD LAYER OVER LAND SHOULD RESULT
IN NOTHING MORE THAN SOME VIRGA ACROSS THE NORTHWEST CWA.

WEDNESDAY AFTERNOON AND NIGHT...WEAK MID-LEVEL RIDGING WILL DEVELOP
OVER THE UPPER GREAT LAKES IN RESPONSE TO ABUNDANT LOW-LEVEL WAA.
WITH INCREASING 850 HPA TEMPS TO 14 TO 16C AND SOME CLEARING ACROSS
THE CWA WEDNESDAY AFTERNOON...TEMPS SHOULD RISE WELL INTO THE 70S TO
LOW 80S. WHILE A COUPLE LIGHT SHOWERS CANNOT BE RULED OUT WITH THE
WAA IN THE AFTERNOON...POPS WERE CUT BACK FOR WEDNESDAY GIVEN
MINIMAL OVERALL SUPPORT IN THE REGION. THE SFC WARM FRONT WILL PUSH
NORTHWARD ACROSS THE CWA WEDNESDAY NIGHT. THE COMBINATION OF PWATS
SURPASSING 1.7 INCHES...THE PRESENCE OF A 45KT LLJ...AND IMPRESSIVE
ISENTROPIC LIFT ON THE 300-310K THETA SFCS ALL POINT TO HEAVY RAIN
ACROSS THE WESTERN CWA OVERNIGHT. MUCAPE OF AROUND 1000 J/KG ALSO
SUPPORTS THIS NOTION. BEST CHANCES FOR HEAVY RAIN LOOK TO BE FROM
THE ARROWHEAD OF MN TO THE WESTERN COUNTIES OF UPPER MI. GREATER
THAN 1 INCH AMOUNTS WILL BE POSSIBLE WHEREVER EMBEDDED THUNDERSTORMS
TRAIN OVER AN AREA. WHILE 0-6KM SHEAR WILL BE AN IMPRESSIVE
50KTS...FREEZING LEVELS WILL BE FAIRLY HIGH...AOA 13KFT.  THIS WILL
RESULT IN JUST A MARGINAL HAIL THREAT WITH ANY STRONGER ELEVATED
STORMS.

SOME GUIDANCE SHOWS THE WARM FRONT STALLING ALONG LAKE SUPERIOR LATE
WEDNESDAY NIGHT. WITH A STRONGER SFC LOW AT THIS POINT TRACKING
EASTWARD ALONG THE INTERNATIONAL BORDER...WOULD EXPECT THE FRONT TO
LIFT FARTHER NORTHWARD. HOWEVER...EXPERIENCE LEANS TO THE FORMER
IDEA. WITH THAT SAID...LAKE TEMPS WELL INTO THE 50S TO LOW 60S AT
THIS POINT SUPPORT A COMPLETE FRONTAL PASSAGE ACROSS THE WESTERN
LAKE.

THURSDAY...THE FORECAST AT THIS POINT WILL BE HIGHLY CONDITIONAL
UPON ON THE MOVEMENT OF THE WARM FRONT AND APPROACHING COLD FRONT.
THURSDAY MORNING LOOKS TO HAVE SOME RESIDUAL SHOWERS AND STORMS
ASSOCIATED WITH THE WARM FRONT AND CONTINUED LOW-LEVEL MOISTURE
TRANSPORT. THINK THINGS WILL CLEAR OUT A DECENT AMOUNT FROM LATE
MORNING THROUGH THE AFTERNOON ACROSS THE CENTRAL CWA. THE EAST IS A
LITTLE MORE QUESTIONABLE IF THE WARM FRONT STALLS ON THE COOLER
EASTERN LAKE SUPERIOR WATERS. THE MID-RANGE MODEL SUITE...EXCLUDING
THE GEM...IS IN GOOD AGREEMENT OF THE FRONTS PROGRESSION...WITH IT
REACHING THE FAR WESTERN CWA AROUND 18Z.

A FAIRLY STOUT CAP AROUND 5KFT WILL SETTLE ACROSS THE AREA BEHIND
THE WARM FRONT...SO ANY CONVECTION WILL BE TIED TO THE STRONGEST
FORCING ALONG THE COLD FRONT. CONDITIONAL UPON ANY
DEVELOPMENT...CONVECTIVE PARAMETERS ARE WORTH A CLOSE LOOK. A POOL
OF MUCAPE VALUES OF UP TO 2000 J/KG ASSOCIATED WITH THE INCREASING
LOW-LEVEL MOISTURE SHOULD REACH THE INTERIOR WESTERN CWA BY LATE
AFTERNOON. 0-6KM SHEAR VECTORS OF 50KTS FROM MAINLY SPEED SHEAR WILL
LIE NEARLY PERPENDICULAR TO THE SFC FRONT. THIS WOULD SUPPORT
DISCRETE STRUCTURES ALONG THE FRONT. THE MAIN FOCUS ATTM IS ACROSS
THE CENTRAL CWA WHERE CLEARING CAN HELP WEAKEN THE CAP AHEAD OF THE
SFC FRONT. ONCE AGAIN...ALL OF THIS IS HIGHLY CONDITIONAL UPON ANY
DEVELOPMENT ALONG THE FRONT.

ANY CONVECTION SHOULD WEAKEN THURSDAY EVEN ACROSS THE EASTERN CWA AS
IT ENTERS A LESS-FAVORABLE ENVIRONMENT IN TERMS OF INSTABILITY.
COMPLETE FRONTAL PASSAGE IS EXPECTED BY LATE THURSDAY NIGHT.

FRIDAY THROUGH MONDAY...WRAP-AROUND MOISTURE WITH THE DEPARTING
SYSTEM MAY BRING DRIZZLE/LIGHT SHOWERS TO MAINLY WEST TO
NORTHWESTERLY FAVORED UPSLOPE REGIONS FRIDAY MORNING. OVERALL DEEPER
MOISTURE WILL BE LIMITED IN THE DRY SLOT BEHIND THE COLD FRONT...SO
CLOUDS SHOULD MIX OUT A DECENT AMOUNT BY THE AFTERNOON. SFC HIGH
PRESSURE OVER THE NORTHERN PLAINS IMPINGING ON A LINGERING SFC
TROUGH OVER LAKE SUPERIOR ON FRIDAY SHOULD RESULT IN GUSTY NW WINDS
ACROSS MUCH OF THE CWA ON FRIDAY. 850 HPA TEMPS FALL TO 1 TO 4C
ACROSS THE CWA ON FRIDAY...LEADING TO SEASONABLY COOL HIGH TEMPS IN
THE LOW TO MID 60S.

REMAINING MOISTURE WILL THEN DEPART THE REGION FRIDAY NIGHT AS A
MID-LEVEL RIDGE AND SFC HIGH PRESSURE BUILD IN FROM THE UPPER MS
VALLEY. LOW PWATS OF UNDER 0.4 INCH AND WEAKENING WINDS WILL ALLOW
FOR SOME COOL TEMPS FRIDAY NIGHT ACROSS AT LEAST THE INTERIOR WEST.
FAVORED GUIDANCE AT THIS POINT IS INDICATING LOW 40S. GIVEN THE
SET-UP...HAVE FOLLOWED THE LOW END OF GUIDANCE. IN FACT...WOULD NOT
BE SURPRISED TO SEE TEMPS FALL WELL INTO THE 30S FOR THE COLDER
LOCATIONS.

A WEAK...MOISTURE-STARVED TROUGH IS PROGGED TO PASS ACROSS THE UPPER
GREAT LAKES SATURDAY NIGHT. WITH MOST OF THE LIMITED FORCING
REMAINING NORTH OF LAKE SUPERIOR...NOTHING MORE THAN SOME MID TO
HIGH CLOUDS ARE EXPECTED. TEMPS SATURDAY NIGHT WILL BE DEPENDENT ON
THESE CLOUDS...SO DID NOT LOWER TEMPS AS MUCH AS FRIDAY NIGHT.
HOWEVER...IN THE ABSENCE OF CLOUDS...CONDITIONS WILL BE FAVORABLE
FOR MORE TEMPS AROUND 40 FOR COLDER LOCATIONS. HIGH PRESSURE WILL
REMAIN IN CONTROL THROUGH SUNDAY AS BROAD LOW PRESSURE FORMS ACROSS
THE NORTHERN AND CENTRAL PLAINS. MODEL SOLUTIONS DIVERGE BY THIS
POINT...BUT CONDITIONS LOOK DRY THROUGH AT LEAST THE FIRST HALF OF
MONDAY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 122 AM EDT TUE SEP 2 2014

EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD WITH
RELATIVELY DRY LLVL AIR SHOWN ON UPSTREAM RAOBS DOMINATING. AN
APRCHG UPR DISTURBANCE/DAYTIME HEATING AND DESTABILIZATION COULD
CAUSE SOME -SHRA AT SAW AND PERHAPS IWD THIS AFTN...BUT THE DRY LLVL
AIR SHOULD MAINTAIN PREDOMINANT VFR WX EVEN IF THE -SHRA OCCUR.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 308 PM EDT MON SEP 1 2014

WINDS WILL BE 20 KNOTS OR LESS THROUGH MOST OF THIS FORECAST PERIOD
EXCEPT FOR THU NIGHT INTO FRIDAY WHERE WEST TO NORTHWEST WINDS
BEHIND A STRONG COLD FRONT WILL APPROACH 30 KNOTS. THIS WILL BE THE
WHEN THE STRONGEST WINDS OCCUR WITH NO GALES EXPECTED AT THIS TIME.
&&

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

$$

SHORT TERM...07
LONG TERM...KLUBER
AVIATION...KC
MARINE...07






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