Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 012011
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
411 PM EDT WED OCT 1 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 345 PM EDT WED OCT 1 2014

WHILE THE UPPER 40S AND LOW 50S FOR LOWS...AND LOW 60S FOR HIGHS MAY
NOT FEEL TOO WARM TONIGHT INTO THURSDAY...THEY WILL BE SLIGHTLY
ABOVE THE NORMAL FOR THIS TIME OF YEAR. IT/S JUST QUITE A CONTRAST
FROM THE WARM WEEKEND THAT WE JUST EXPERIENCED. S-SW FLOW WILL
REMAIN NEAR THE SFC...WITH DOWNSLOPE AREAS ALONG THE LAKE SUPERIOR
SHORELINE STAYING IN THE 50S FOR LOWS TONIGHT.

THE INITIAL SHOT OF SHOWERS CONTINUES TO SLOWLY PUSH IN FROM THE
W...MOVING UP AHEAD OF THE SFC TROUGH OVER W MN. THE CURRENT RADAR
IMAGERY SHOWS AND MODEL ANALYSIS SHOWS THE SHORTWAVE EXTENDING DOWN
THROUGH E MN AND W WI PUSHING ACROSS THE W HALF OF UPPER MI PRIOR TO
00Z. LIGHTNING HAS BEEN NON-EXISTENCE...AND WITH MINIMAL CAPE TO
WORK WITH OVER OUR REGION...THE TS POTENTIAL HAS BEEN DOWNPLAYED FOR
THE REST OF THE AFTERNOON HOURS. PRECIP DRIES UP SIGNIFICANTLY OVER
S MN AND CENTRAL WI...HAVE LOWERED POPS INITIALLY LATE THIS
AFTERNOON AND EARLY THIS EVENING /MAINLY DOWN TO CHANCE VALUES NEAR
THE WI BORDER/ TO ACCOUNT FOR THIS. LOOKS LIKE A MODERATE TO THIN
LINE OF PRECIP WILL CROSS THE CWA THIS EVENING INTO THE OVERNIGHT
HOURS...WITH PW VALUES MAXING OUT AROUND 200 PERCENT OF NORMAL.

A MAINLY N-S ORIENTED 250MB JET AVERAGING 80KTS WILL WEAKEN AS IT
MOVES OVER THE W HALF OF THE CWA THIS EVENING. THE MAIN JET PUNCHING
ACROSS NE AND KANSAS THIS AFTERNOON WILL SURGE NE INTO CENTRAL WI
OVERNIGHT...BEFORE LIFTING ACROSS MN/WI/UPPER MI THURSDAY
MORNING...INCREASING TO 120KTS OVER WI AND W LAKE SUPERIOR BY 18Z
THURSDAY. GIVEN THE SLIGHTLY MORE E TRACK OF THE SFC LOW TO OUR S
RIDING UP ALONG THE STAGNANT TROUGH OVER THE AREA...A SLIGHT E PUSH
TO THE LIKELY/DEF POPS SEEMED REASONABLE FOR THE DAY TUESDAY...WITH
THE BEST MOISTURE /PW VALUES 200-250 PERCENT OF NORMAL REMAINING S
OF THE WI BORDER THROUGH 00Z FRIDAY.

.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 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 258 PM EDT WED OCT 1 2014

MVFR CEILINGS ARE PRETTY STANDARD THIS AFTERNOON...WITH IFR CEILINGS
UNDER THE BROAD SWATH OF PRECIP EXTENDING ACROSS NE MN THROUGH S WI.
THE E PROGRESSION OF THIS MOISTURE HAS BEEN SLOW GOING. WITH
A N-S ORIENTED SFC TROUGH MOVING FROM W MN TO THE VERY FAR W CORNER
OF LAKE SUPERIOR BY LATE EVENING...EXPECT THE BETTER CHANCE OF RAIN
AND IFR CEILINGS TO PUSH TO ALL 3 TAF SITES THIS EVENING AND
OVERNIGHT. WOULD NOT BE SURPRISED TO SEE IFR CEILINGS TOWARD
DAYBREAK AT IWD AND SAW /ESPECIALLY WITH LIGHT FLOW AND PLENTY OF
LINGERING LOW LEVEL MOISTURE/. WHILE THERE WILL LIKELY BE A LAPSE IN
RAINFALL THURSDAY MORNING TO EARLY AFTERNOON...BEFORE RETURNING WITH
MORE MODERATE TO POTENTIALLY HEAVY RAIN THURSDAY NIGHT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 PM EDT WED OCT 1 2014

A WEAKENING PRES GRADIENT OVER THE UPPER LAKES THRU THU WILL RESULT
IN DIMINISHING S BACKING E WINDS. BUT THEN A SURFACE LOW PRESSURE
TRACKING FROM THE UPPER MIDWEST INTO NW ONTARIO IS FORECAST TO DEEPEN
AND BRING ABOUT STRONG TO GALE FORCE NW WINDS TO MUCH OF LAKE
SUPERIOR ON FRI INTO SAT. ALTHOUGH THERE IS STILL SOME UNCERTAINTY ON
THE TIMING OF THE GALE EVENT...OPTED TO POST A GALE WATCH FOR MOST
OF THE CENTRAL PORTION OF THE LAKE FROM FRI AFTERNOON INTO SAT
AFTERNOON...WHEN THE POSSIBILITY OF GALES IS HIGHEST. AS THE DEEP LO
OVER ONTARIO SLOWLY SHIFTS FARTHER TO THE N...THE WNW WINDS WILL
SLOWLY DIMINISH ON SUN AND MON.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR
     LSZ263>266.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KF
LONG TERM...KC
AVIATION...KF
MARINE...KC




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