Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 270909
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
409 AM EST TUE JAN 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM EST TUE JAN 27 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALOFT OVER
THE GREAT LKS BTWN HI AMPLITUDE RDG OVER THE ROCKIES AND DEEP TROF
OVER THE E SUPPORTING INTENSE WINTER STORM THAT IS IMPACTING NEW
ENGLAND. SHRTWV DIGGING SEWD WITHIN THIS NW FLOW/DEEPER CLDS THAT
CAUSED PERIOD OF SN LAST EVNG ARE NOW SE OF THE AREA...SO LINGERING
LIGHT SN OVER THE CENTRAL CWA IS DIMINISHING WITH THE APRCH OF
SHRTWV RDG AXIS/DNVA/DEEP LYR QVECTOR CNVGC AND DRIER MID LVL AIR
SHOWN ON THE 00Z INL/YPL RAOBS. THESE RAOBS SHOW SOME LLVL MSTR BLO
INVRN...SO PLENTY OF LO CLDS LINGER UPSTREAM OVER NRN MN/NW ONTARIO.
HOWEVER...WITH 00Z H85 TEMP ONLY -5C AT INL...THE INCOMING AIRMASS
IS NOT SUFFICIENTLY COLD TO SUPPORT LES. COLDER AND DRIER LLVL AIR
IS STILL PRESENT TOWARD THE E AND ARCTIC HI PRES IN QUEBEC...WITH
MOCLR SKIES REPORTED EARLY THIS MRNG AT NEWBERRY AND THE SAULT.

MAIN FCST CONCERNS FOR TODAY/TNGT WL BE CLD TRENDS/IMPACT ON TEMPS.

TODAY...UPR MI WL BE DOMINATED BY DNVA/DEEP LYR QVECTOR DVGC
ASSOCIATED WITH APRCHG SHRTWV RDG. SO AFTER ANY LINGERING LIGHT SN
ENDS EARLY THIS MRNG...THE DAY SHOULD BE DRY AS SFC RDG AXIS
EXTENDING WSW FM THE HI CENTER IN QUEBEC SHIFTS OVER THE CWA.
DESPITE THE MID LVL DRYING...LINGERING LLVL MSTR TRAPPED BLO
LOWERING/STRENGTHENING SUBSIDENCE INVRN WL LIKELY MAINTAIN GENERALLY
MOCLDY SKIES...IN LINE WITH UPSTREAM OBS. ONE EXCEPTION SHOULD BE
THE ERN CWA...WHERE LIGHT E WIND WL MAINTAIN THE LLVL DRY AIR AND
ALLOW FOR MOSUNNY SKIES. ANOTHER AREA THAT MAY SEE SOME CLRG IS NEAR
LK SUP OVER THE NW CWA WHERE THE LLVL SW FLOW ON THE NRN FLANK OF
THE SFC RDG AXIS WL DOWNSLOPE AND RESULT IN LOWERING THE INVRN BASE
FURTHER. GOING FCST HI TEMPS MAINLY IN THE 20S...COLDEST OVER THE
E AND WARMEST OVER THE W...LOOK TO BE IN GOOD SHAPE.

TNGT...A SHRTWV IS FCST TO TRACK THRU FAR NRN ONTARIO. ALTHOUGH
LINGERING SHRTWV RDG AXIS WL FORCE THIS DISTURBANCE TO PASS TOO FAR
TO THE N TO BRING PCPN TO ALL BUT FAR NRN LK SUP LATE...AN INCRSG
LLVL ACYC SW FLOW BTWN THE SFC RDG AXIS SLIDING OVER LOWER MI AND
FALLING MSLP IN ONTARIO ASSOCIATED WITH THE PASSING SHRTWV WL ADVECT
SOME DRIER AIR INTO THE CWA. THIS DRYING PLUS MORE LLVL SUBSIDENCE
ASSOCIATED WITH THE STRENGTHENING ACYC FLOW WL LIKELY BREAK UP THE
LO CLDS OVER MUCH OF THE CWA...ESPECIALLY OVER NW NEAR LK SUP WHERE
SW WINDS DOWNSLOPE. OVER THE E...THE SW FLOW OFF LK MI MIGHT DRAW
MORE LO CLDS INTO THAT AREA. DESPITE ANY CLRG OF THE LOWER CLDS...
STRONGER WINDS AND INCRSG MID/HI CLDS ON THE SRN FLANK OF THE
DISTURBANCE PASSING TO THE N WL LIMIT THE DIURNAL TEMP FALL. EXPECT
THE LOWEST MIN TEMPS OVER THE E...WHERE TEMPS WL FALL OFF QUICKLY IN
THE EVNG BEFORE THE WINDS HAVE A CHC TO PICK UP A BIT OR ANY
CLDS ROLL IN LATER.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 437 PM EST MON JAN 26 2015

THERE WILL BE MINOR FLUCTUATIONS IN THE UPPER RIDGE ALONG THE
WESTERN COAST OF NORTH AMERICA...BUT IT WILL LARGELY STAY IN PLACE
THROUGH THE LONG TERM FORECAST. THIS WILL LEAD TO NORTHWESTERLY
FLOW ALOFT OVER THE UPPER GREAT LAKES REGION AND SEND A SERIES OF
SHORTWAVES THROUGH THE AREA.

THE UPPER GREAT LAKES REGION WILL BE UNDER WEAK RIDGING WITHIN THE
NORTHWESTERLY FLOW ALOFT TO START THE PERIOD...WHILE THE SURFACE
RIDGE WILL BE SLIDING EAST OF THE AREA. EXPECT THERE TO BE SOME
LINGERING LOWER CLOUDS OVER THE CENTRAL PART OF THE CWA...WHILE
THERE WILL BE HIGH CLOUDS SPREADING OVER THE WESTERN CWA AHEAD OF
THE NEXT SYSTEM. THESE CLOUDS WILL KEEP TEMPS FROM FALLING TOO MUCH
IN THAT AREA...BUT OVER THE EAST...CLEARING IN THE EVENING WILL
ALLOW TEMPERATURES TO QUICKLY FALL INTO THE LOWER SINGLE DIGITS
ABOVE ZERO. DID TREND TOWARDS THE BETTER PERFORMING GEM MODELS OVER
THE EAST IN THOSE CLEAR SKY AND RADIATIONAL COOLING SITUATIONS.

FOCUS THEN TURNS TO THE INVERTED TROUGH PUSHING EAST TOWARDS THE
AREA ON WEDNESDAY (FROM A LOW MOVING OUT OF THE NORTHERN/CENTRAL
PLAINS) AND THREE SHORTWAVES THAT WILL COME TOGETHER OVER THE GREAT
LAKES REGION THROUGH THURSDAY. THE INITIAL AREA OF PRECIPITATION
SHOULD STAY WELL TO THE NORTH OF UPPER MICHIGAN ON WEDNESDAY (TIED
TO THE DEEPER MOISTURE AND BROAD WARM AIR ADVECTION OVER NORTHERN
LAKE SUPERIOR. BUT AS A SECOND SHORTWAVE SLIDES SOUTHEAST INTO THE
AREA FROM MANITOBA ON WEDNESDAY NIGHT...EXPECT THE PRECIPITATION
SWEEP SOUTH THROUGH THE AREA WITH THE 850-700MB TROUGH. SHOULD SEE
1-3 INCHES OF SNOW MOVE ACROSS THE AREA ON WEDNESDAY NIGHT...WITH
THE HIGHEST AMOUNTS OVER THE EAST. COLDER AIR IS DELAYED BEHIND THE
SYSTEM...SO DON/T EXPECT MUCH IN THE WAY OF LAKE ENHANCEMENT...BUT
DID FACTOR IN SOME TERRAIN ENHANCEMENT FOR THURSDAY. WITH THAT LACK
OF COLD AIR...THE CLOUD THERMAL PROFILE IS ON THE EDGE FOR ICE
CRYSTALS. AT THIS POINT...THINK THERE WILL BE ENOUGH AND LEFT OUT
FREEZING DRIZZLE...BUT IT WILL BE SOMETHING TO WATCH.

THE COLD AIR FINALLY ARRIVES ON THURSDAY NIGHT AND REMAINS INTO
FRIDAY UNDER NORTH-NORTHWEST WINDS ALOFT. EXPECT LIGHT LAKE EFFECT
TO OCCUR IN THOSE SNOW BELTS...BUT WITH SUBSIDENCE FROM HIGH
PRESSURE BUILDING INTO THE UPPER MISSISSIPPI VALLEY...INVERSION
HEIGHTS WILL STRUGGLE TO RISE MUCH ABOVE 4-5KFT. THUS...THINK
ACCUMULATIONS WILL BE ON THE LOW SIDE...BUT THEY WILL BE EFFICIENT
AT REDUCING VISIBILITIES DUE TO THE CLOUD BEING ABOVE THE DGZ.
WINDS WILL BACK ON FRIDAY AFTERNOON/NIGHT AS THE HIGH SLIDES JUST
TO THE SOUTH OF THE AREA.

FORECAST BECOMES A LITTLE UNCERTAIN AS MODELS DIVERGE ON THE UPPER
LEVEL FEATURES. ALL IN ALL...LOOKS LIKE A WEAK TROUGH WILL SLIDE
ACROSS THE AREA ON SATURDAY AND USHER IN ANOTHER SURGE OF COLD AIR
(MID -20S 850MB TEMPS) INTO THE UPPER GREAT LAKES REGION. WILL
CONTINUE TO SHOW LAKE EFFECT POPS BEHIND THAT TROUGH IN THE NW WIND
SNOW BELTS FOR SATURDAY NIGHT INTO MONDAY. WITH THE AMOUNT OF COLD
AIR...EXPECT LIMITED SNOWFALL AMOUNTS BUT GOOD VISIBILITY
RESTRICTION.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1223 AM EST TUE JAN 27 2015

LINGERING LOW-LEVEL MOISTURE WILL KEEP ALL TAF SITES AT IFR TO LOW
MVFR CONDITIONS OVERNIGHT.  EXPECT SOME DIURNAL IMPROVEMENT TO
HIGHER END MVFR LATE TUE MORNING INTO THE AFTERNOON UNDER A LIGHT
SOUTHERLY FLOW.  VFR CONDITIONS MAY BE POSSIBLE AT KIWD TUE EVENING
AS DRIER AIR WORKS IN FROM THE SOUTH.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 AM EST TUE JAN 27 2015

EXPECT S TO SW WINDS UNDER 20 KTS TO DOMINATE THRU WED AS A HI PRES
RIDGE OVER UPPER MI TODAY SINKS SLOWLY INTO THE LOWER GREAT LAKES.
ON THE NORTHERN FLANK OF A HI PRES RIDGE ORIENTED ACROSS THE CENTRAL
GREAT LAKES. LO PRES WILL THEN TRACK FROM THE MID MISSISSIPPI VALLEY
WED NIGHT TO THE LOWER LAKES THU NIGHT. BEHIND THE LOW...N TO NW
WINDS WILL INCREASE TO 20-30KT AND THEN TO GALE FORCE LATE THU AND
THU NIGHT. SINCE THESE STRONG WINDS WILL DRAW MUCH COLDER ARCTIC AIR
INTO THE UPPER LAKES...HEAVY FREEZING SPRAY WILL DEVELOP OVER MUCH
OF THE LAKE AND CONTINUE INTO FRI...WHEN WINDS/WAVES WILL DIMINISH
WITH THE CLOSER APPROACH OF CANADIAN HI PRES. ANOTHER DISTURBANCE
AND COLD FRONT MAY SWING ACROSS THE UPPER LAKES ON SAT.
&&

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

$$

SHORT TERM...KC
LONG TERM...SRF
AVIATION...VOSS
MARINE...KC


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