Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 031721
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1221 PM EST TUE MAR 3 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM EST TUE MAR 3 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW
REGIME ACRS NAMERICA WITH ARCTIC AND POLAR/SUBTROPICAL BRANCH RDG
OVER THE GREAT LKS EARLY THIS MRNG. LOCAL 00Z ROABS SHOW A VERY DRY
AIRMASS WITH PWATS UNDER 0.10 INCH AT INL/GRB/APX...ON AVERAGE 33
PCT OF NORMAL...AND H7 DEWPT DEPRESSIONS UP TO 40-45C. THERE ARE TWO
SHRTWVS THAT WL HAVE A SGNFT IMPACT ON UPR MI WX...ONE IN EACH
STREAM. THE POLAR/SUBTROPICAL BRANCH SHRTWV IS LIFTING NEWD INTO THE
WRN PLAINS EARLY THIS MRNG AND SUPPORTING A WELL DEFINED BAROCLINIC
LEAF CLD...WITH SOME VERY COLD CLD TOPS OVER NEBRASKA AND IOWA JUST
TO THE N OF H85 WARM FNT ATTENDANT TO DVLPG SFC LO PRES IN FAR NW
KANSAS AND WHERE THERE IS ENHANCED UPR DVGC IN EXIT REGION OF
SUPPORTING 140KT H3 JET MAX. IN THE ARCTIC BRANCH...THERE IS A
STRONG SHRTWV DIGGING SEWD INTO MANITOBA...WITH 12HR H5 HGT FALLS
APRCHG 150M IN THE VIGOROUS DPVA AHEAD OF THIS FEATURE. SFC COLD FNT
HANGING S OF THE ACCOMPANYING SFC LO MOVING INTO FAR NW ONTARIO
EXTENDS S INTO THE NRN PLAINS AND IS APRCHG NW MN. CLOSER TO HOME...
A BAND OF COLDER CLD TOPS IS NOTED NEAR THE WI BORDER ALONG AXIS OF
FGEN SHOWN BEST BTWN ABOUT H7-5. HOWEVER...DRYNESS OF ANTECEDENT
AIRMASS HAS SO FAR LIMITED THE COVERAGE/INTENSITY OF ACCOMPANYING
LIGHT SN.

MAIN FCST CONCERNS THIS FCST PERIOD WL BE ON POPS/SN TOTALS
ASSOCIATED WITH THE TWO SHRTWVS NOTED ABOVE. SINCE THESE
DISTURBANCES WL REMAIN OUT OF PHASE...OVERALL SN TOTALS EXPECTED
TODAY OVER UPR MI WL NOT BE EXCESSIVE BEFORE MUCH COLDER AIR
FOLLOWING THE ARCTIC BRANCH FROPA SURGES INTO THE AREA TNGT AND
BRINGS A RETURN OF SOME LES.

TODAY...SRN BRANCH DISTURBANCE IS FCST TO ACCELERATE TO THE NE AND
ACROSS THE UPPER MIDWEST IN FAST WSW FLOW BTWN THE TWO BRANCHES AS
THE NRN BRANCH SHRTWV PUSHES INTO NW ONTARIO...WITH COLD FNT
ATTENDANT TO ACCOMPANY SFC LO REACHING THE WRN CWA LATE IN THE DAY.
ARRIVAL OF SOME VIGOROUS DEEP LYR QVECTOR CNVGC/UPR DVGC IN LEFT
EXIT OF SUPPORTING H3 JET MAX AS WELL AS DEEP ISENTROPIC ASCENT IN
THE SSW FLOW ALF IN ADVANCE OF THESE DISTURBANCES WL CAUSE BAND OF
PATCHY SN NEAR THE WI BORDER EARLY RELATED TO MID LVL FGEN TO EXPAND
IN COVERAGE DURING THE MRNG HRS. SINCE THE SHARPEST ISENTROPIC
ASCENT AS WELL AS FGEN THAT IS MAXIMIZED IN THE H7-6 LYR IS FCST TO
IMPACT MAINLY THE SE HALF OF THE CWA...WHERE SOME LK ENHANCEMENT OFF
LK MI LIMITED SOMEHWAT BY ICE COVERAGE IS PSBL IN THE LLVL SLY FLOW
AHEAD OF THE SFC LO ASSOCIATED WITH THE SRN BRANCH DISTURBANCE...
EXPECT THE GREATER SN TOTALS IN THIS AREA. WITH SPECIFIC HUMIDITY IN
THE H7-75 LYR UP TO 3G/KG...3-6 INCHES OF SN SEEMS A GOOD BET FOR 6-
9 HR PERIOD OF STEADY PCPN EXPECTED BEFORE ARRIVAL OF DNVA/VIGOROUS
QVECTOR DVGC DURING THE MID TO LATE AFTN IN THE WAKE OF THIS
DISTURANCE WL BRING AN END TO THE STEADIER SN W-E AND OVER THE FAR E
BY 00Z WED. ALTHOUGH THE SHARPER ISENTROPIC ASCENT/FGEN/MSTR
TRANSPORT WL TEND TO MISS THE WRN CWA...EXPECTED HIER SN/WATER
RATIOS IN THAT AREA DUE TO A DEEPER FCST DGZ MAY HELP RAISE SN
TOTALS AT LEAST TO THE 3 INCH THRESHOLD IN THAT AREA. WL MAINTAIN
GOING ADVY FOR THE ENTIRE CWA AS IS EVEN THOUGH THE HEADLINE MAY BE
DROPPED A FEW HRS EARLY OVER THE W.

TNGT...UPR MI WL BE DOMINATED BY DEEP LYR QVECTOR DVGC/SUBSIDENCE IN
THE WAKE OF THE DEPARTING DISTURBANCES. BUT ARRIVAL OF COLDER AIR IN
THE WAKE OF ARCTIC BRANCH COLD FROPA THAT IS FCST TO DROP H85 TEMPS
TO AS LO AS -26C OVER THE W BY 12Z WED WL RESULT IN LES...MAINLY IN
AERAS THAT ARE DOWNSTREAM OF HOLES IN THE ICE COVER OBSVED JUST E OF
THE MN ARROWHEAD...THE BAYFIELD PENINSULA AND THE KEWEENAW PENINSULA
IN THE FCST WNW H925 FLOW. BUT STILL RATHER EXTENSIVE ICE COVER...
AS WELL AS DISAPPEARING DGZ OVER THE W RELATED TO THE CHILL OF THE
INCOMING AIRMASS...WL HOLD DOWN SN TOTALS. THE BEST CHANCE FOR MORE
NMRS SN SHOWERS APPEARS TO BE E OF MUNISING IN ALGER COUNTY THAT WL
BE DOWNWIND OF THE AREA OF OPEN WATER E OF THE KEWEENAW AND WHERE
THE ONSHORE 290 FLOW WL BE MORE PARALLEL TO THAT AREA OF OPEN WATER.
GUSTY WINDS RELATED TO FCST H925 WINDS UP TO 35-40KTS/STRONG CAA AND
DESTABILIZATION WL CAUSE SOME GUSTY WINDS...ESPECIALLY NEAR THE LK
SUP SHORE. GUSTS IN THE MORE EXPOSED LOCATIONS E OF MUNISING MAY
APRCH ADVY CRITERIA. OVER THE SCENTRAL...EXPECT SOME CLEARING...WITH
MIN TEMPS FALLING BLO ZERO OVER THE INTERIOR W HALF...ESPECIALLY NEAR
THE WI BORDER WHERE LK MODERATION WL BE MINIMAL OR ABSENT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 356 AM EST TUE MAR 3 2015

A SHORTWAVE AND SFC TROUGH WILL SHIFT ACROSS THE CWA ON WED/WED
EVENING WITH 850MB TEMPS AS COLD AS -27C. LOW LEVEL WINDS WILL BE
OUT OF THE WNW THROUGH THE AFTERNOON BUT WILL VEER AROUND TO THE NW
BEHIND THE TROUGH WED EVENING. MORNING AND EARLY AFTERNOON WINDS
GUSTING TO 30-40MPH ALONG THE LAKE SUPERIOR SHORE WILL LEAD TO
BLOWING SNOW AND SIGNIFICANTLY REDUCED VISIBILITIES OVER THE
KEWEENAW AND EAST OF MUNISING DUE TO THE MORE WNW WIND
DIRECTIONS...BUT WINDS WILL DECREASE IN THE LATE AFTERNOON AND
EVENING. OF COURSE...LES WILL RESULT EVEN WITH A MOSTLY ICE COVERED
LAKE SUPERIOR...ESPECIALLY WITH THE SHORTWAVE COMING THROUGH. LES
WILL DIMINISH WED NIGHT INTO THU AS A SFC RIDGE MOVES IN FROM THE W
WHILE WINDS BACK. GENERALLY HAVE 1-2 INCHES IN WNW WIND SNOWBELTS ON
WED...WITH AROUND ANOTHER INCH WED NIGHT INTO THU.

FOR FRI THROUGH NEXT MON...SEVERAL SHORTWAVES MAY MOVE THROUGH THE
REGION DURING THIS TIME. A STRONGER SHORTWAVE LOOKS TO MOVE THROUGH
ON SUN/SUN NIGHT...BUT THE OTHER WILL BE PRETTY WEAK. PRECIPITATION
FORECAST CONFIDENCE IS QUITE LOW GIVEN UNCERTAINTIES WITH THE
SHORTWAVES. THAT BEING SAID...ISOLATED TO SCATTERED LES IS POSSIBLE
IN W-NW WINDS SO WILL INCLUDE THAT IN THE FORECAST. TEMPS DO LOOK TO
MODERATE...AND SHOULD REACH NORMAL VALUES THIS WEEKEND. LOOKING EVEN
FARTHER AHEAD...MODELS CONTINUE TO SHOW THE W COAST RIDGE SHIFTING E
INTO THE CENTRAL CONUS MID TO LATE NEXT WEEK...WHICH WOULD BRING
ABOVE NORMAL TEMPS AND START MELTING THE SNOWPACK.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1220 PM EST TUE MAR 3 2015

ARRIVAL OF STRONGER DYNAMIC FORCING WL RESULT IN STEADY SN AND CAUSE
PREDOMINANT IFR VSBYS INTO MID AFTN. AS THIS FORCING EXITS W-E THIS
AFTN... CONDITIONS WL IMPROVE TO MVFR. A STRONG COLD FNT WL THEN
PASS LATE THIS AFTN OVER THE W AND DURING THE EVNG AT SAW. GUSTY WNW
WINDS WL DVLP IN ITS WAKE. EXPECT THE STRONGEST WINDS AT THE MORE
EXPOSED IWD AND ESPECIALLY THE CMX LOCATIONS. DESPITE EXTENSIVE ICE
COVER ON LK SUP...MVFR CONDITIONS ARE LIKELY TO PREDOMINANT AT THESE
LOCATIONS WITH AN UPSLOPE WIND COMPONENT. DOWNSLOPE FLOW INTO SAW WL
CAUSE VFR CONDITIONS THERE TNGT FOLLOWING THE COLD FROPA.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 AM EST TUE MAR 3 2015

S WINDS UP TO 25 KTS TODAY IN ADVANCE OF AN APPROACHING
COLD FRONT WILL SHIFT TO THE WNW FOLLOWING THE PASSAGE OF THIS FRONT
LATE TODAY/TONIGHT. TIGHTENING PRES GRADIENT AND STRONG COLD AIR
ADVECTION AHEAD OF ARCTIC HI PRES MOVING INTO THE NORTHERN PLAINS
WILL BRING A PERIOD OF WNW GALES INTO WED...MAINLY ACROSS CNTRL AND
ERN LAKE SUPERIOR. UPGRADED GALE WATCH TO A WARNING FOR THESE AREAS.
AFTER WED...NO GALE FORCE WINDS ARE EXPECTED THRU THE REMAINDER OF
THE FORECAST PERIOD. LATEST OFFICIAL ICE CONCENTRATION ON LAKE
SUPERIOR IS AROUND 94 PCT. EVEN WITH STRONG WINDS AT TIMES THIS WEEK
THAT WILL OPEN SOME HOLES IN THE ICE...THE SIGNIFICANT ICE COVERAGE
SHOULD PERSIST AS TEMPERATURES STAY BELOW FREEZING.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
     FOR MIZ001>007-009>014-084-085.

LAKE SUPERIOR...
  GALE WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR LSZ267.

  GALE WARNING FROM 10 PM THIS EVENING TO 7 PM EST WEDNESDAY FOR
     LSZ266.

  GALE WARNING FROM 10 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
     LSZ265.

  GALE WARNING FROM 10 PM THIS EVENING TO 1 PM EST WEDNESDAY FOR
     LSZ264.

LAKE MICHIGAN...
NONE.
&&

$$

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


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