Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 292031
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
331 PM EST THU JAN 29 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 331 PM EST THU JAN 29 2015

COLD FRONT HAS BLOWN THROUGH. TEMPS ARE FALLING STEADILY INTO THE
UPPER TEENS WEST AND IN THE 20S NEAR LAKE MICHIGAN. NW WINDS ARE
GUSTING NEAR 50 MPH CLOSE TO LK SUPERIOR AND EVEN ABOVE 30 MPH
FARTHER INLAND. ATTN IS ON SNOW AMOUNTS AND LOW VSBY TONIGHT AS LAKE
EFFECT SNOW INCREASES. RADAR SHOWS INCREASING ECHOES THIS AFTN. HAD
SOME FZDZ INTO EARLY AFTN...BUT SEEMS TO HAVE FADED NOW AS COLDER
AIR AT H9-H85 SPILLS ACROSS UPR MICHIGAN. UPSTREAM THE SOUNDINGS FM
12Z SHOWED INVERSIONS AROUND H9 OR MAYBE SLIGHTLY HIGHER. THERE IS A
WAVE ALOFT PRODUCING LGT SNOW OVER MINNESOTA ARROWHEAD AND WESTERN
LK SUPERIOR AND THIS DISTURBANCE SWINGS ACROSS THIS EVENING. EXPECT
TO SEE INCREASING LES IN NW-NNW FLOW AREAS OF NCNTRL UPR MICHIGAN.
SOUNDINGS SHOW MAJORITY OF LAKE CONVECTIVE LAYER WITHIN THE DGZ SO
THAT WILL HELP OUT ACCUMS...BUT STRONG WINDS WILL ALSO ACT TO BREAK
APART SNOWFLAKES. SMALLER FLAKES AND GUSTY WINDS WILL LEAD TO POOR
VSBY ESPECIALLY NEAR LK SUPERIOR WHERE ICE IS JUST OFFSHORE.

WENT AHEAD AND ISSUED A LAKE EFFECT SNOW AND BLOWING SNOW ADVY FOR
ALGER AND NORTHERN SCHOOLCRAFT COUNTIES AS EXPECTED INCREASE OF SNOW
SHOWERS WILL OCCUR THIS EVENING WHEN PEOPLE WILL STILL BE OUT
TRAVELING. MAY SEE A FEW HOUR PERIOD WHERE SNOWFALL RATES PUSH UP
TOWARD 1 INCH PER HOUR. EVEN SO...TOTAL SNOW AMOUNTS INTO LATE
TONIGHT WILL ONLY TOP OUT AT 3 TO 5 INCHES. BASED ON SNOW AMOUNTS
ALONE WOULD NOT HAVE WENT WITH THE ADVY...BUT GIVEN THE GUSTY
WINDS/BLOWING SNOW AND POOR VSBY ALONG WITH EXPECTED SNOW AMOUNTS
THOUGHT IT WOULD BE GOOD TO HAVE ADVY OUT FOR WHERE HEAVIEST SNOW IS
EXPECTED THIS EVENING. VSBY AT TIMES THIS EVENING MAY FALL TO ONE-
QUARTER MILE OR LESS IN THE HEAVIER SNOW SHOWERS. SNOW AMOUNTS
ELSEWHERE ALONG LK SUPERIOR WILL BE HELD DOWN BY THE LOWERING
INVERSIONS AND DRYING MOVING IN BEHIND THE DISTURBANCE. LARGE HIGH
PRESSURE CURRENTLY OVER THE CANADIAN PRAIRIES MOVING IN WILL ALSO
RESULT IN DIMINISHING TREND. BY LATE TONIGHT ONLY LES OF NOTE WILL
LIKELY BE IN THE SNOWBELTS OF ALGER THROUGH LUCE COUNTY...AT A
DIMINISHED STATE COMPARED TO THIS EVENING. LOWS TONIGHT KIND OF
TRICKY GIVEN FLOW OF LAKE CLOUDS STILL AROUND WHICH WILL OFFSET COLD
AIR ADVECTION. SOME ZERO READINGS POSSIBLE WITH ANY CLEARING
LATE...ESPECIALLY AWAY FM LK SUPERIOR IN THE SCNTRL AND ALSO IN THE
FAR EAST.

LES CONTINUES TO DIMINISH ON FRIDAY AND SHOULD LIFT TO ONLY FAR
NORTHERN LUCE COUNTY BY AFTN AS LOW-LEVEL WINDS BACK WEST WITH THE
HIGH MOVING IN. TEMPS WILL ONLY REACH LOW TO MID TEENS AS THE LAKE
EFFECT CLOUDS ARE REPLACED WITH INCREASING MID CLOUDS TIED TO WARM
AIR ADVECTION AHEAD OF NEXT SYSTEM THAT WILL MOVE OVER THE
AREA ON FRIDAY NIGHT.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 411 AM EST THU JAN 29 2015

FCST FOCUS IN THE MEDIUM AND EXTENDED RANGE WL BE ON THE IMPACT OF
SEVERAL CLIPPER TYPE SHRTWVS THAT ARE FCST TO MOVE THRU A MEAN UPR
TROF IN ERN NAMERICA. UNDER THE PERSISTENT NW FLOW ALOFT...EXPECT
BLO TO WELL BLO NORMAL TEMPS TO DOMINATE DURING THIS TIME WITH A
STEADY FEED OF CNDN AIR. WITH THE COLD AIR SURGES...LES WL BE AN
OBVIOUS CONCERN.

FRI...SFC HI PRES IS FCST TO SHIFT FM OVER MN TOWARD THE OH RIVER
VALLEY BE 00Z SAT. AS NW WINDS IN THE MRNG BACK TO THE W AND THEN
THE SW LATE...LINGERING LES OVER THE W WL BECOME CONFINED TO OVER
THE KEWEENAW AND END OVER THE E EXCEPT NEAR THE SHORE E OF GRAND
MARAIS TOWARD 00Z SAT. ALTHOUGH THE LK CLDS WL BE SHIFTING
OFFSHORE...MORE MID/HI CLDS IN ADVANCE OF ANOTHER SHRTWV MOVING SE
WITHIN THE NW FLOW ALF WL BE PUSHING INTO THE UPR LKS.

FRI NGT/SAT...SHRTWV EMBEDDED IN THE NW FLOW ALOFT WL BE MOVING INTO
NW MN AT 00Z SAT AND IS THEN FCST TO SLIDE SE THRU NCENTRAL WI BY
12Z SAT AND THEN ACROSS LOWER MI ON SAT. AT THE SAME TIME...ANOTHER
STRONGER SHRTWV WL BE MOVNG FM CENTRAL CANADA INTO FAR NW ONTARIO BY
12Z SAT BEFORE MOVING TO JUST S OF JAMES BAY BY 00Z SUN. UPR MI WL
BE IMPACTED MAINLY BY THE WEAKER SRN DISTURBANCE. ALTHOUGH A BAND OF
RELATIVELY WEAK QVECTOR CNVGC IS FCST TO SLIDE ACROSS UPR MI ON FRI
NGT INTO SAT MRNG ON THE CYC SIDE OF THIS SRN SHRTWV...ACCOMPANYING
ISENTROPIC ASCENT/MSTR INFLOW IS FCST TO BE RELATIVELY WEAK. SO WL
FCST ONLY CHC POPS OVER MOST OF THE CWA AND MAINLY BTWN 03Z SAT AND
15-18Z SAT...WHEN THE FORCING ACCOMPANYING THE SRN SHRTWV AND A COLD
FNT ATTENDANT TO THE NRN SHRTWV ARE FCST TO EXIT THE ERN CWA AND
GIVE WAY TO SOME VIGOROUS DEEP LYR QVECTOR DVGC. MAINTAINED SOME
LIKELY POPS OVER THE NRN TIER OF THE CWA CLOSE TO THE STRONGER NRN
SHRTWV AND WHERE SHARPER LLVL CNVGC WL ACCOMPANY THE SAT COLD FROPA.
THE COLDEST 00Z GFS/12Z ECMWF RUNS SHOW H85 TEMPS IN THE WAKE OF THE
SAT COLD FROPA PLUNGING AS LO AS -25C BY 00Z SUN...BUT QUICK
TRANSITION TO A MORE DIFFLUENT/ACYC H925 N FLOW AND INVRN BASE
FALLING TO H85-875 WL TEND TO LIMIT LES INTENSITY. RELATIVELY
MODERATE TEMPS INTO SAT MRNG WL FALL THRU THE AFTN AS THE COLDER AIR
SURGES INTO THE AREA IN THE STEADY N FLOW AHEAD OF ARCTIC HI PRES
BLDG SEWD IN SCENTRAL CANADA.

SAT NGT THRU SUN NGT...UPR MI WL REMAIN DOMINATED BY A COLD N
BACKING WNW LLVL FLOW OF ARCTIC AIR ASSOCIATED WITH ARCTIC HI PRES
MOVING FM OVER ALBERTA/SASKATCHEWAN AT 00Z SUN INTO THE UPR MS RIVER
VALLEY BY 12Z MON. EXPECT TEMPS TO RUN WELL BLO NORMAL AND LES TO
CONTINUE NEAR LK SUP WITH H85 TEMPS FCST TO REMAIN NOT FAR FM -22C
TO -25C. SAT NGT COULD BE PARTICULARLY CHILLY OVER THE E WITH THE N
H925 FLOW ALLOWING SOME DRAINAGE OF COLD AIR INTO THAT AREA OFF
ONTARIO. ALTHOUGH FCST ACYC NATURE OF THE H925 FLOW AND NEAR ABSENCE
OF THE DGZ ASSOCIATED WITH THE VERY LO H85 TEMPS WL LIMIT LES
AMOUNTS...SOME OF THE MODELS HINT THERE MAY BE SOME ENHANCED CNVGC
ALONG A LK INDUCED TROF STRETCHING FM THE KEWEENAW TOWARD WHITEFISH
PT THAT WL INTENSIFY AS THE LARGER PRES GRADIENT RELAXES AND A
SHRTWV EMBEDDED IN THE NW FLOW APRCHS ON SUN/SUN NGT. RAISED POPS
WELL ABOVE THE CONSENSUS TO LIKELY ALONG THIS AXIS.

MON...LES ALONG THE LK INDUCED TROF WL BEGIN TO DIMINISH/SHIFT OUT
INTO LK SUP WITH THE APRCH OF A SFC RDG AXIS EXTENDING N FM THE HI
CENTER SHIFTING TOWARD THE OH VALLEY AND THE ASSOCIATED BACKING LLVL
FLOW. BUT THE MORE W WIND COMPONENT WL MEAN LESS LK MODERATION AND
PERSISTENT WELL BLO NORMAL SFC TEMPS EVEN AS THE H85 TEMPS MODERATE
A BIT FASTER.

TUE/WED...THE LONGER RANGE GUIDANCE HINTS ANOTHER CLIPPER TYPE
DISTURBANCE WL PASS THRU THE UPR LKS ON TUE...WITH H85 TEMPS
REBOUNDING TO NEAR -15C IN THE WAA BTWN THIS FEATURE AND HI PRES
MOVING INTO THE MID ATLANTIC. BUT ANOTHER ARCTIC SURGE LOOKS TO
FOLLOW ON WED AS THE SHRTWV PASSAGE REAMPLIFIES THE ERN TROF AND THE
NW FLOW IN ADVANCE OF THE NEXT CNDN HI SINKING INTO THE NRN PLAINS
ADVECTS H85 TEMPS AS LO AS -25 TO -28C INTO THE UPR LKS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1258 PM EST THU JAN 29 2015

COLD FRONT IS EAST OF UPPER MICHIGAN AND BLUSTERY NORTHWEST WINDS OF
20-30 KTS IN GUSTS ARE ALREADY OCCURRING. EVENTUALLY THERE WILL BE A
SWITCH BACK TO MORE NUMEROUS LAKE EFFECT SNOW SHOWERS. OFF AND ON
ISOLD SNOW SHOWERS WILL AFFECT KIWD AND KCMX THIS AFTN WITH A WINDOW
FOR GREATER COVERAGE AND INTENSITY LATE THIS AFTN AS LIFT INCREASES
DUE TO AN UPPER LEVEL DISTURBANCE. SNOW SHOWERS WILL THEN DIMINISH
AGAIN BY LATE EVENING AS HIGH PRESSURE AND DRIER LOW-LEVEL AIR
ARRIVE FM THE NORTHWEST. AT KSAW...WILL HAVE TO CONTEND WITH MIX OF
SNOW AND FZDZ THIS AFTN BEFORE COLDER AIR SWITCHES THE PRECIP TO
LAKE EFFECT SNOW SHOWERS INTO THE EVENING. EXPECT DIMINISHING AND
ENDING TREND TO SNOW SHOWERS OVERNIGHT TONIGHT. WINDS WILL REMAIN
GUSTY AT ALL THE TAF SITES UNTIL LATER TONIGHT. VSBY MAINLY MVFR AT
ALL THE SITES THOUGH MAY DIP TO IFR BRIEFLY LATE THIS AFTN OR EARLY
EVENING. BY LATE TONIGHT INTO FRIDAY...MAINLY MVFR OR VFR FLYING
CONDITIONS ARE ANTICIPATED.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 355 AM EST THU JAN 29 2015

LOW PRESSURE SYSTEM NEAR N LAKE SUPERIOR THIS MORNING WILL MOVE INTO
QUEBEC THIS AFTERNOON WHILE ANOTHER LOW NEAR CHICAGO SHIFTS EAST
INTO NEW ENGLAND ON FRIDAY MORNING. MEANWHILE...A HIGH OVER S
CENTRAL CANADA WILL MOVE SE INTO MN ON FRIDAY. IN BETWEEN THE
EXITING LOW AND NEARING HIGH...STRONG N-NNW GALES GUSTING 35 TO
AROUND 40KTS WILL DEVELOP THIS AFTERNOON OVER MAINLY CENTRAL AND E
LAKE SUPERIOR. LOOK FOR WINDS TO SLOWLY DIMINISH LATE THIS EVENING
AND OVERNIGHT...WITH GUSTS REMAINING 25-30KTS THROUGH DAYBREAK
FRIDAY. GIVEN THE STRONG WINDS...AND COLDER AIR SURGING IN...HEAVY
FREEZING SPRAY WILL BE POSSIBLE OVER THIS SAME AREA INTO EARLY
FRIDAY MORNING. WINDS WILL THEN QUICKLY DIMINISH AND REMAIN LESS
THAN 30KTS THROUGH FRIDAY NIGHT.

AS THIS HIGH DRIFTS INTO THE OH RIVER VALLEY ON SATURDAY...A TROUGH
WILL SLIDE ACROSS THE UPPER GREAT LAKES. A FEW N TO NW GUSTS OF 30
TO NEAR 35KTS WILL BE POSSIBLE SATURDAY AFTERNOON AND EVENING.
EXPECT HIGH PRESSURE OVER CENTRAL CANADA ON SATURDAY TO MOVE SE INTO
THE N PLAINS ON SUNDAY...AND THE MID MS RIVER VALLEY ON MONDAY.
WINDS SHOULD DIMINISH FOR A TIME SUN BEFORE INCREASING AGAIN MONDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST FRIDAY FOR MIZ006-085.

LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST FRIDAY FOR
     LSZ264>267.

  GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ265>267.

  GALE WARNING UNTIL 1 AM EST FRIDAY FOR LSZ263-264.

  HEAVY FREEZING SPRAY WARNING UNTIL 5 AM EST FRIDAY FOR LSZ263.

LAKE MICHIGAN...
NONE.
&&

$$

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


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