Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281142
AFDMQT

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

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 603 AM EDT SUN SEP 28 2014

...ONE MORE UNSEASONABLY WARM DAY TODAY...AND QUITE LIKELY THE LAST
DAY WITH TEMPERATURES THIS HIGH FOR THE REST OF THE YEAR...

PER WATER VAPOR IMAGERY AND RUC ANALYSIS...STRONG RIDGE THAT WAS
EXTENDING INTO NRN ONTARIO IS BEING SUPPRESSED BY SHORTWAVE TROF
THAT HAS BEEN MOVING ACROSS SOUTHERN CANADA. THIS TROF IS SUPPORTING
A SHARP COLD FRONT THAT CURRENTLY EXTENDS FROM SE ND TO JUST S OF
JAMES BAY. JUST BEHIND FRONT...TEMPS QUICKLY FALL OFF INTO THE 40S
AND 30S...GIVING AN IDEA OF THE DRAMATICALLY COLDER CONDITIONS THAT
WILL SWEEP INTO THE AREA FOR MON. MID LEVEL LOW THAT WAS CENTERED
ALONG THE IA/MO BORDER 24 HRS AGO HAS MOVED LITTLE...NOW OVER IA.
SCT/BKN MAINLY THIN HIGH CLOUDS TO THE NE OF THIS FEATURE HAVE
HELPED TO KEEP RADIATION FOG A LITTLE LESS WIDESPREAD AND LESS DENSE
EARLY THIS MORNING.

FCST SOUNDINGS SHOW LITTLE CHANGE IN TEMP PROFILE FROM YESTERDAY...
SO LARGELY UTILIZED YESTERDAYS MAX TEMPS AS A BASIS FOR TODAYS MAX
TEMPS. TEMP RISE THIS MORNING SHOULD ALSO FOLLOW A SIMILAR DIURNAL
CURVE TO WHAT OCCURRED YESTERDAY MORNING. PRETTY GOOD CHC RECORD
HIGH OF 77F FOR NWS KMQT SITE WILL FALL TODAY. SHARP COLD FRONT TO
THE N WILL DRIFT S TODAY AND SHOULD REACH THE KEWEENAW LATE IN THE
AFTN. AS IS CURRENTLY NOTED WITH FRONTAL BOUNDARY...PCPN WILL
CONTINUE TO OCCUR MOSTLY ON THE COLD SIDE OF THE SFC COLD FRONT AS
NICE FRONTOGENETICAL CIRCULATION UNDER RIGHT ENTRANCE OF UPPER JET
WILL CONTINUE TO SUPPORT PCPN ON THE COLD SIDE OF THE SFC FRONT.
THAT SAID...WEAK PRES GRADIENT AHEAD OF FRONT WILL ALLOW LAKE
BREEZES TO DEVELOP TODAY. WITH A FEW HUNDRED J/KG OF MLCAPE...LAKE
BREEZE MAY BE SUFFICIENT TO KICK OFF ISOLD SHRA THIS AFTN ACROSS
PORTIONS OF THE CNTRL AND ERN FCST AREA. MOST HIGH RES MODEL
GUIDANCE CONTINUES TO SHOW THIS POTENTIAL.

SFC COLD FRONT WILL CONTINUE TO DRIFT S TONIGHT WITH PCPN REMAINING
MOSTLY ON THE COLD SIDE OF THE BOUNDARY...SUPPORTED BY
FRONTOGENETICAL CIRCULATION AS DISCUSSED ABOVE. TRAILING SHORTWAVE
CURRENTLY OVER SCNTRL CANADA WILL DIG INTO THE UPPER GREAT LAKES
MON. WITH BEST OVERLAP OF FGEN AND DEEP LAYER FORCING FROM SHORTWAVE
PER QVECTORS PASSING JUST N AND E OF FCST AREA...HEAVIER/STEADIER
SHRA/RA SHOULD PASS N AND E OF THE AREA. HOWEVER...DECENT FORCING
STILL SUPPORTS LIKELY TO CATEGORICAL POPS SPREADING SE TO THE
KEWEENAW AFTER MIDNIGHT TONIGHT AND TO WRN AND NRN UPPER MI BY 12Z
MON.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN SEP 28 2014

MONDAY WILL BE A SIGNIFICANT CHANGE IN THE WEATHER FOR UPPER
MICHIGAN...AS A COLD FRONT SWEEPS SOUTHEAST ACROSS THE AREA LATE
SUNDAY NIGHT THROUGH MONDAY. AS THIS OCCURS...EXPECT A BAND OF
SHOWERS TO BE MOVING ACROSS THE AREA ALONG AND BEHIND THE SURFACE
COLD FRONT BEFORE SINKING SOUTHEAST OF THE AREA ON MONDAY EVENING.
EVEN AS A BULK OF THE RAIN HAS SHIFTED OVER THE SOUTHEAST HALF OF
THE CWA ON MONDAY AFTERNOON...STILL EXPECT PLENTY OF LOW CLOUDS AND
LIGHT RAIN/DRIZZLE OVER THE AREA...ESPECIALLY THOSE FAVORED BY
NORTH-NORTHEAST UPSLOPE WINDS. IN ADDITION...WITH 900MB TEMPS
AROUND -1C AND LAKE SUPERIOR TEMPS BETWEEN 6-12C WOULD EXPECT AT
LEAST SOME LAKE ENHANCEMENT FOR THE AREAS NEAR LAKE SUPERIOR. WITH
INVERSION HEIGHTS RUNNING AROUND 3-3.5KFT DON/T EXPECT THE RAIN TO
BE TOO HEAVY...BUT ENOUGH TO LEAD TO A PERSISTANT LIGHT RAIN. WILL
CONTINUE TO SHOW LIKELY TO DEFINITE POPS IN THE FAVORED WIND
DIRECTIONS NEAR LAKE SUPERIOR AND AT LEAST CHANCES ELSEWHERE INTO
THE EVENING HOURS ON MONDAY. MODELS THEN SHOWING INVERSION HEIGHTS
FALLING THROUGH THE NIGHT UNDER THE INCREASED SUBSIDENCE FROM THE
HIGH PRESSURE RIDGE (HIGH CENTERED IN NORTHEAST ONTARIO) MOVING INTO
THE AREA. THUS...WILL SHOW DECREASING POPS THROUGH THE NIGHT AND
EVENTUALLY CLOUD COVER THROUGH THE DAY ON TUESDAY INTO TUESDAY
NIGHT. THE COMBINATION OF THE RAIN WITH STIFF NORTH-NORTHEAST WINDS
(15-25KTS) AND AFTERNOON TEMPERATURES IN THE MID 40S (30-35
DEGREES COLDER THAN THIS AFTERNOON) OVER THE NORTH HALF WILL MAKE
FOR A SIGNIFICANTLY DIFFERENT DAY THAN WHAT HAS BEEN EXPERIENCED
OVER THE LAST SEVERAL DAYS.

AS THE U.P. FINALLY STARTS TO BREAK OUT OF THE CLOUDS FROM MONDAY/S
SYSTEM...THE NEXT UPPER TROUGH WILL BE WORKING TOWARDS THE AREA ON
TUESDAY NIGHT AND BRING THE NEXT PERIOD OF UNSETTLED WEATHER TO THE
AREA FOR WEDNESDAY AFTERNOON THROUGH SATURDAY. THIS PERIOD OF
UNSETTLED WEATHER WILL BE ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY OVER THE WESTERN CONUS SHIFTING EAST THROUGH THE AREA
DURING THAT PERIOD. THE FIRST WAVE FROM THAT UPPER TROUGH WILL MOVE
INTO THE AREA ON WEDNESDAY AFTERNOON AHEAD OF A WARM FRONT LIFTING
NORTHEAST TOWARDS THE AREA FROM A LOW NEAR LAKE WINNIPEG. WILL SHOW
INCREASING POPS FROM SOUTHWEST TO NORTHEAST FOR WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT...WITH THE HIGHEST POPS (LIKELY) RUNNING ALONG
THE COLD FRONT THAT WILL BE MOVING THROUGH WESTERN AND CENTRAL
UPPER MICHIGAN LATE WEDNESDAY NIGHT AND THURSDAY. AS THIS COLD
FRONT IS SLOWLY WORKING EAST ACROSS THE AREA...A STRONG SHORTWAVE
DIVING SOUTHEAST THROUGH THE UPPER TROUGH WILL POTENTIALLY LEAD TO
THE INTENSIFICATION OF A LOW IN THE MID MISSISSIPPI VALLEY ON
THURSDAY EVENING. THIS LOW WILL CONTINUE TO INTENSIFY AS IT LIFTS
NORTHEAST ACROSS UPPER MICHIGAN ON FRIDAY MORNING AND THEN
NORTH-NORTHEAST INTO CANADA. WILL CONTINUE LIKELY POPS AS THIS LOW
MOVES THROUGH...ALTHOUGH CONFIDENCE IN THE STRENGTH IS LIMITED DUE
TO THE VARYING SOLUTIONS SHOWN IN THE MODELS (NOT UNEXPECTED WITH
UPSTREAM PHASING OF STRONG SHORTWAVES). THE 12Z ECMWF ENSEMBLE
MEMBERS ARE NOT MUCH OF A HELP WITH AROUND HALF OF THEM NOT SHOWING
A LOW RIDING UP THE COLD FRONT. WITH 12Z ECMWF AND 00Z GFS AT LEAST
SIMILAR IN THEIR IDEAS (ALTHOUGH GFS IS MUCH SLOWER IN DEPARTING THE
LOW)...WILL FOLLOW THAT IDEA FOR NOW FOR POPS (CHANCE/LIKELY) AND
WIND (GUSTY NORTHWEST WINDS TO 30KTS ON FRIDAY NIGHT) FORECAST.
LATE ARRIVING 00Z ECMWF HAS BACKED AWAY FROM THE LOW PRESSURE SYSTEM
AND JUST KEEPING A BROAD SURFACE TROUGH MOVING THROUGH. BASED OFF
THE 12Z ECMWF ENSEMBLE MEMBERS...THAT DOESN/T SEEM TO UNREASONABLE.
SATURDAY SHOULD SEE A DIMINISHING OF BOTH OF THOSE AS THE LOW PULLS
OUT OF THE AREA AND A HIGH PRESSURE RIDGE MOVES IN FROM THE
SOUTHWEST.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 741 AM EDT SUN SEP 28 2014

VFR CONDITIONS WILL CONTINUE TODAY AT KIWD/KCMX/KSAW AHEAD OF A
SHARP COLD FRONT DROPPING S THRU NRN ONTARIO. LAKE BREEZE
DEVELOPMENT THIS AFTN COULD TRIGGER ISOLD -SHRA IN CNTRL UPPER
MI...BUT POTENTIAL IS VERY LOW FOR KSAW TO BE AFFECTED BY A -SHRA IF
IN FACT SOME DO DEVELOP. SO...NO MENTION WAS INCLUDED IN FCST. AS
THE COLD FRONT DROPS ACROSS THE AREA TONIGHT...EXPECT ALL TERMINALS
TO FALL ABRUPTLY TO IFR/LIFR. -SHRA/-RA WILL SPREAD S BEHIND THE
COLD FRONT AS WELL WITH KCMX MOSTLY LIKELY TO SEE PCPN. BEST
POTENTIAL FOR PCPN AT KIWD/KSAW WILL OCCUR NEAR THE END OR JUST
BEYOND THIS FCST PERIOD.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 603 AM EDT SUN SEP 28 2014

SHARP COLD FRONT CURRENTLY OVER NRN ONTARIO WILL DROP S...PASSING
ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT. WITH A WEAK PRES
GRADIENT AHEAD OF FRONT...WINDS WILL REMAIN ON THE LIGHT SIDE
TODAY...MOSTLY UNDER 20KT. ON THE FLIP SIDE...DRAMATIC CHANGES WILL
OCCUR AFTER THE FRONT PASSES. STRONG COLD AIR ADVECTION COMBINED
WITH POST FRONTAL PRES RISES WILL RESULT IN N TO NE WINDS OF 20-30KT
ACROSS MUCH OF LAKE SUPERIOR WITH A FEW GALE FORCE GUSTS POSSIBLE
ACROSS CENTRAL PORTIONS OF THE LAKE TONIGHT INTO MON MORNING. WINDS
WILL THEN GRADUALLY DIMINISH MON AFTN AND NIGHT AS HIGH PRES BUILDS
OVER NRN ONTARIO. WINDS UNDER 20KT WILL BE THE RULE TUE THRU THU.
HOWEVER...AS PRES GRADIENT TIGHTENS SOME ON WED BTWN DEPARTING HIGH
PRES AND AN APPROACHING COLD FRONT...SOUTHERLY WINDS MAY BE A LITTLE
STRONGER ON WED...MAINLY OVER ERN LAKE SUPERIOR. LOOKING FARTHER
OUT...THERE ARE SOME HINTS THAT A STRENGTHENING FALL STORM SYSTEM
WILL LIFT THRU THE UPPER LAKES LATE WEEK...BRINGING THE POTENTIAL
FOR GALES.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON






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