Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 020848
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
448 AM EDT THU OCT 2 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EDT THU OCT 2 2014

DESPITE THE SOUTHERLY FLOW IN LOW-LEVELS...MAIN WARM FRONT IS WELL
TO SOUTH OVER CNTRL MISSISSIPPI RIVER VALLEY. FRONT ESSENTIALLY IS
JUST TO SOUTH OF WHERE MULTIPLE CLUSTERS OF TSRA ARE CURRENTLY
OCCURRING. STRONG LOW PRESSURE OVER NORTHERN MANITOBA MOVING TOWARD
HUDSON BAY AND A NORTH-SOUTH ORIENTED FRONT FROM THE LOW TOWARD THE
UPPER MISSISSIPPI RIVER VALLEY IS REASON FOR THE SOUTH WINDS OVER UPR
LAKES REGION.

SHOWERS HAVE DEVELOPED OVER SOUTHERN AND EASTERN CWA THIS MORNING
OUT AHEAD OF SHORTWAVE AND ON NOSE OF JET STREAK OVER WISCONSIN AND
WITHIN AREA OF GREATER MOISTURE ADVECTION. THERE IS ALSO A TOUCH OF
MID-LEVEL INSTABILITY BUT NO TSRA HAVE BEEN OBSERVED THUS FAR.
EXPECT SHRA OVER MAINLY EASTERN CWA INTO AT LEAST EARLY AFTN WHILE
REST OF CWA SHOULD BE WITHIN A LULL AS MUCH STRONGER SYSTEM IN FORM
OF TWO MAIN SHORTWAVES...ONE OVER FOUR CORNERS AND THE OTHER STRONGER
ONE OVER WESTERN CANADA DIVING SOUTHEAST OVER SOUTHERN BRITISH
COLUMBIA AND ALBERTA...DOES NOT BEGIN TO AFFECT UPPER GREAT LAKES
UNTIL LATER THIS AFTN AND MORE EMPHATICALLY INTO TONIGHT. BACK TO
TODAY...EXPECT TEMPS TO END UP A BIT ABOVE NORMAL /NORMAL HIGHS UPR
50S TO LOW 60S/ AS 950-900MB TEMPS CONTINUE TO WARM AHEAD OF LARGER
SCALE UPPER TROUGH OVER WESTERN CANADA AND ROCKIES AND CLOUD COVER BY
AFTN SHOULD THIN OUT SOME. EXPECT MAX TEMPS INTO THE 60S...WITH SHOT
AT EVEN SOME UPPER 60S FOR SOME LOCATIONS OVER WEST HALF OF CWA.

INTO THIS EVENING THE WESTERN CANADA SHORTWAVE DIVES ACROSS NORTHERN
PLAINS WHILE THE FOUR CORNERS WAVE HEADS ACROSS KS INTO WESTERN
MO. OVERNIGHT THE NORTHERN PLAINS SHORTWAVE WILL BECOME THE MAIN
SHORTWAVE AS IT PHASES WITH THE SOUTHERN PLAINS WAVE. LIFT WILL
INCREASE DUE TO DEEPENING OF LARGER SCALE TROUGH FROM SCNTRL CANADA
TO SOUTHERN PLAINS/12 HR HEIGHT FALLS UP TO 150DAM SPREADING TOWARD
UPPER GREAT LAKES AND BROAD MODERATE/STRONG H7-H5 Q-VECTOR
CONVERGENCE OVER UPR GREAT LAKES. ENHANCEMENT TO LIFT AS H3 JET
STREAK AMPLIFIES FM UPPER GREAT LAKES TO NORTHERN ONTARIO/HUDSON
BAY...PLACING MUCH OF UPR MICHIGAN WITHIN RIGHT ENTRANCE REGION.
WITH THE BACKGROUND OF THIS LARGER SCALE SUPPORT...STRONG SSW-NNE
MOISTURE ADVECTION RAMPS UP AHEAD OF THE INITIAL NORTH-SOUTH
ORIENTED SFC TROUGH AND AS WAVE OF SFC LOW PRESSURE THAT IS FORMING
OVER SOUTHERN PLAINS THIS MORNING STEADILY DEEPENS AS IT LIFTS ALONG
TROUGH TO A POSITION SOMEWHERE VCNTY OF EASTERN LK SUPERIOR BY
DAYBREAK FRIDAY. OVERALL...CONSENSUS OF MODEL GUIDANCE AND EXPECTED
FORCING AND MOISTURE ADVECTION SUPPORTS LARGE SHIELD OF MODERATE
RAIN LIFTING ACROSS UPR MICHIGAN THIS EVENING AND CONTINUING THOUGH
MOST OF THE NIGHT. QPF AMOUNTS SEEM LIKELY TO REACH 0.75 INCHES OVER
EAST CWA...WHILE AMOUNTS SHOULD STAY BLO 0.50 INCH OVER WEST CWA AS
THAT AREA IS FARTHER REMOVED FM ADVECTION OF MOISTURE WITH PWATS
OVER 200 PCT OF NORMAL. STRENGTH OF DYNAMICS SUGGESTS SOME EMBEDDED
TSRA MAY OCCUR...THOUGH BEST CHANCE WILL BE OVER EAST HALF OF CWA
LATER THIS EVENING AND OVERNIGHT CLOSER TO STRONGER H85-H7 MOISTURE
TRANSPORT AND TRACK OF DEEPENING SFC LOW.

EVEN WITH THE DEEPENING LOW MOVING ACROSS TONIGHT...APPEARS STRONGER
WINDS WILL NOT MATERIALIZE UNTIL MORE SO ON FRIDAY. MINS TONIGHT
WILL BE ON THE MILD SIDE FOR EARLY OCTOBER...WITH NEAR 50 DEGREE
READINGS WEST TO MID-UPR 50S FOR THE EAST.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 406 PM EDT WED OCT 1 2014

EXPECT A MORE ACTIVE PATTERN TYPICAL OF FALL IN THE GREAT LKS TO
DOMINATE THE MEDIUM INTO THE EXTENED FCST PERIOD AS PHASING SHRTWVS
RESULT IN DEEPENING SFC LO/CLOSED UPR LO IN ONTARIO. WELL BLO NORMAL
TEMPS/DEEP CYC NW FLOW THRU AT LEAST THE WEEKEND WL BRING LOTS OF
CLDS AND LK EFFECT/ENHANCED PCPN TO MUCH OF THE CWA. THE FIRST
ACCUMULATING SN OF THE SEASON COULD FALL OVER THE HIER TERRAIN OF
THE W AND NCENTRAL AT SOME TIME THIS WEEKEND.

THU NGT THRU FRI...HOW QUICKLY TWO SHRTWVS...ONE NOW OVER THE DESERT
SW AND ANOTHER IN WRN CANADA...PHASE AND INTERACT WITH YET ANOTHER
DISTURBANCE FCST TO DIG INTO SCENTRAL CANADA ON FRI WL DETERMINE THE
TRACK AND INTENSITY OF A SFC LO THAT IS FCST TO MOVE FM THE UPR
MIDWEST LATE ON THU INTO ONTARIO ON FRI. THE 12Z GFS AND NAM HAVE
TRENDED TOWARD A SIMILAR SCENARIO SHOWING A STEADILY DEEPENING SFC
LO OVER SW WI ON THU EVNG MOVING INTO CENTRAL UPR MI BY 12Z FRI AND
THEN TO NEAR JAMES BAY BY FRI EVNG UNDER A DEEPENING UPR TROF/12 HR
H5 HGT FALLS UP TO 150M. EXPANSIVE AREA OF DEEP LYR QVECTOR CNVGC ON
THE ERN FLANK OF THE DEEPENING TROF AND UPR DVGC IN RRQ OF 110KT H3
JET MAX ARE FCST TO MOVE OVER THE AREA ON THU EVNG AHEAD OF THE SFC
LO AND INTERACT WITH PWAT APRCHG 1.75 INCH OVER THE SE CWA...ABOUT
225 PCT OF NORMAL. BAND OF SHARP H85-7 FGEN ON THE WRN FLANK OF SFC
LO TRACK IS FCST TO TRACK OVER THE WRN CWA AS WELL. THESE VIGOROUS
DYNAMICS/AMPLE MSTR JUSTIFY GOING CATEGORICAL POPS ON THU NGT AS
WELL AS MENTION OF SOME TS ON THU NGT AT LEAST CLOSER TO THE SFC LO
TRACK EVEN THOUGH FCST INSTABILITY IS NOT PARTICULARLY IMPRESSIVE
/SSI NO LOWER THAN 0 TO +1/. CONSIDERING THE IMPRESSIVE DYANMICS AND
HI PWAT...SOME HEAVY RA WL BE PSBL. ONCE THE SFC LO/DYNAMIC SUPPORT
LIFT TO THE N ON FRI...THERE IS A WSHFT TO THE WNW AND SOME UPR
DRYING BEGINS...THE PCPN WL TEND TOWARD A MORE SHOWERY REGIME...WITH
MORE SHOWERS IN AREAS THAT UPSLOPE WITH THE WNW WIND. THESE WINDS WL
TURN GUSTY AS THE H925 WINDS ARE FCST TO INCRS UP TO 30-40 KTS UNDER
FALLING H85 TEMPS TOWARD 0C OVER THE W LATE ON FRI THAT WL ENHANCE
DESTABILIZATION/MIXING.

FRI NGT...PASSAGE OF A REINFORCING SECOND COLD FNT ON THE SW FLANK
OF DEEPENING LO IN ONTARIO IS FCST TO DRAW COLDER AIR INTO THE UPR
LKS...WITH FCST H85 TEMPS DIPPING AS LO AS -3 TO -4C OVER THE W
TOWARD 12Z SAT. IN CONCERT WITH AREA OF DEEP LYR QVECTOR CNVGC THAT
IS PROGGED TO SHIFT ACRS THE AREA ON CYC SIDE OF SUPPORTING H5
SHRTWV...EXPECT A PERIOD OF LK ENHANCED SHOWERS. SINCE FCST H85-1000
THKNS IS FCST TO FALL NO LOWER THAN ABOUT 1305M THRU 12Z SAT...THE
PCPN SHOULD REMAIN IN THE FORM OF RA. BUT IF THE SOMEWHAT COLDER GFS
IS CORRECT...AREAS NEAR IRONWOOD COULD SEE SOME SN MIX IN TOWARD 12Z
SAT AS THIS MODEL FCSTS THE WBZ HGT TO FALL AS LO AS 700FT AGL AT
THAT TIME.

SAT THRU SUN NGT...DEEP...CHILLY AND MOIST CYC NW FLOW ARND CLOSED
UPR LO IN NW ONTARIO RESULTING FM THE PHASING OF SHRTWVS/DEEPENING
SFC LO WL DOMINATE THE GREAT LKS. WITH H85 TEMPS FCST AS LO AS -4 TO
-6C...EXPECT PLENTY OF CLDS AND LK EFFECT PCPN. SHRTWVS ROTATING
ARND THE CLOSED LO WL BRING PERIODS OF HEAVIER LK ENHANCED PCPN WHEN
DEEPER MSTR EXTENDS THRU THE -10C ISOTHERM...MAINLY IN AREAS FAVORED
BY THE EXPECTED NW FLOW. WL TEND HIER THAN MODEL CONSENSUS POPS IN
THESE AREAS...BUT WL LIMIT POPS TO HI LIKELY DUE TO TIMING
UNCERTAINTY ON THE SHRTWV PASSAGES. EXPECT TEMPS...ESPECIALLY
DAYTIME HI TEMPS...TO RUN WELL BLO NORMAL. ON SAT NGT...THE LK
EFFECT PCPN COULD BECOME MIXED WITH SN OVER THE HIER TERRAIN OF THE
W AND NCENTRAL AS H100-85 THKNS IS PROGGED TO FALL TOWARD 1290M.

WITH A LENGTHY PERIOD OF STRONG NW WINDS ON LK SUP...INCLUDING GALES
FOR A TIME...AND HI LAKE LEVELS (LK SUP IS CURRENTLY ABOUT 6 INCHES
BLO THE RECORD HI FOR THIS TIME OF YEAR)...BEACH EROSION/FLOODING
MAY BECOME A PROBLEM FOR AREAS THAT ARE EXPOSED TO WAVES GENERATED
BY NW WINDS. CONTINUED MENTION OF THIS POTENTIAL IN THE HWO.

MON THRU WED...WHILE SOME OF THE EXTENDED MODELS/ENSEMBLE GUIDANCE
HINT THE DEEP CYC FLOW WL WEAKEN EARLY NEXT WEEK AS DEEP UPR LO IN
ONTARIO SHIFTS FARTHER TO THE N AND ALLOWS A RETURN OF A MORE ZONAL
FLOW INTO THE UPR LKS...A GOOD DEAL OF THE GUIDANCE INDICATES A DEEP
TROF/OVERALL CYC NW FLOW WL LINGER. EVEN THE MODELS THAT SHOW A
GREATER RELAXATION OF THE TROF INDICATE A SERIES OF SHRTWVS WL
IMPACT THE UPR LKS DURING THIS TIME. SO WL CARRY AT LEAST LO CHC
POPS THRU THE EXTENDED PERIOD. ALTHOUGH TEMPS MIGHT RETURN TO NEAR
NORMAL IF THE THE MORE ZONAL FLOW DVLPS...MODEL CONSENSUS SUGGESTS
TEMPS WL RUN BLO NORMAL THRU WED.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 141 AM EDT THU OCT 2 2014

MVFR CONDITIONS WILL CONTINUE OVERNIGHT THROUGH THU AFTERNOON AT
KCMX AND KIWD. AS NEXT SYSTEM APPROACHES THU EVENING...CONDITIONS
WILL RAPIDLY DETERIORATE TO IFR/LIFR AT KCMX AND KIWD WITH UPSLOPE
RAIN AND FOG. IFR CONDITIONS WILL DEVELOP AT KSAW WITH UPSLOPE SOUTH
LOW LEVEL FLOW CAUSING SOME FOG THERE OVERNIGHT. DRIER AIR COMES IN
THU MORNING AND CONDITIONS SHOULD GO TO MVFR AND THEN WILL DROP AGAIN
TO IFR THU EVENING AS RAIN MOVES BACK INTO KSAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 AM EDT THU OCT 2 2014

EXPECT DIMINISHING S WINDS THIS MORNING OVER THE EAST. WINDS WILL
REMAIN LIGHT THROUGH MOST OF TONIGHT AS SFC LOW TO THE NORTH ACROSS
LK SUPERIOR. ONCE THE LOW LIFTS TO THE NORTH OF LK SUPERIOR ON
FRIDAY...STRONG WEST WINDS WILL SPREAD ACROSS LK SUPERIOR DUE TO
TIGHT PRESSURE GRADIENT AND THE ARRIVAL OF COLDER AIR. GALE FORCE
WINDS EXPECTED LATER FRIDAY AFTN...AND THESE WILL INCREASE TO 35-40
KTS FRIDAY NIGHT INTO SATURDAY AS WINDS SHIFT TO THE NORTHWEST AS
COLDER AIR MOVES ACROSS LK SUPERIOR. GALE WATCH IN EFFECT FOR ALL
BUT FAR WESTERN LK SUPERIOR FRIDAY AFTERNOON THROUGH EARLY SATURDAY
AFTERNOON. AS IT STANDS NOW...GALE WARNINGS WILL EVENTUALLY BE
ISSUED EITHER LATER TODAY OR TONIGHT.

THOUGH GALES SHOULD DIMINISH ON SATURDAY AFTERNOON...WEST WINDS
20-30 KTS WILL PERSIST INTO SUNDAY AND SUNDAY NIGHT WITH GUSTY
SOUTHWEST WINDS EXPECTED MONDAY INTO TUESDAY OUT AHEAD OF ANOTHER
LOW PRESSURE SYSTEM DROPPING IN FROM SCNTRL CANADA.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR
     LSZ263>267.

LAKE MICHIGAN...
NONE.
&&

$$

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




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