Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 270728
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
328 AM EDT FRI MAR 27 2015

.UPDATE...
ISSUED AT 711 PM EDT THU MAR 26 2015

DUE TO THE DRYNESS OF UPSTREAM AIRMASS IN THE MN ARROWHEAD AND
ADJOINING ONTARIO...WITH SFC DEWPT DEPRESSIONS AOA 20F SUPPORTING
WELL MIXED AND INVERTED V T/TD PROFILES...OPTED TO CANX ADVYS FOR
GOGEBIC AND ONTONAGON COUNTIES. THERE IS A SHRTWV AND SOME BKN CLDS
OVER WRN LK SUP THAT WL LIKELY BRING ABOUT AT LEAST A BRIEF UPTICK
IN LES COVERAGE/INTENSITY IN THIS AREA TOWARD MID OR LATE EVNG WHEN
THE IMPACT OF THE DAYTIME HEATING/MIXING BEGIN TO WANE AND A
FAVORABLE UPSLOPE N WIND IS STILL IN PLACE...BUT LIMITED WINDOW OF
DYNAMIC SUPPORT ASSOCIATED WITH THE PASSING SHRTWV SUGGEST
ADDITIONAL SN ACCUMS WL NOT REACH ADVY CRITERIA.

OF GREATER CONCERN IS AREA OF SN SHOWERS IMPACTING FAR ERN MARQUETTE
AND WRN ALGER COUNTY IN 340 DEGREE UNIDIRECTIONAL FLOW BLO INVRN
BASE ARND 6K FT MSL AS SHOWN ON THE MQT 88D VWP. BUMPED UP FCST SN
TOTALS IN THIS AREA WITH SOME DYNAMIC FORCING AHEAD OF THE APRCHG
SHRTWV...BUT IMPACT OF INCOMING DRY AIR AND SLOWLY VEERING WINDS
THRU THE NGT SHOULD HOLD ACCUMS BLO ADVY CRITERIA IN THIS AREA.
&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM EDT THU MAR 26 2015

COLD FRONT HAS MOVED THROUGH WITH NW WINDS IN PLACE OVER LK SUPERIOR
AND UPR MICHIGAN. TEMPS HAVE FALLEN INTO THE UPPER TEENS ALONG MUCH
OF LK SUPERIOR AND ARE IN THE 20S INLAND AND TOWARD LK MICHIGAN.
MAINLY A PURE LAKE EFFECT SETUP ATTM AS MOST OF THE ENHANCEMENT FROM
EARLIER SHORTWAVE AND COLD FRONTAL PASSAGE HAVE MOVED AWAY FM THE
AREA. MQT VWP POINTS TO INVERSIONS UP TO 5KFT WITH RAP/NAM SHOWING
H85 TEMPS TO AROUND -17C BY 00Z FRIDAY. CYCLONIC LOW-LEVEL FLOW
LINGERS BTWN THE DEPARTING COLD FRONT AND HIGH PRESSURE CENTERED
OVER MANITOBA. VISIBLE SATELLITE SHOWS GOOD DRYING ADVECTING OVER
WESTERN LK SUPERIOR BUT THERE IS STILL DECENT CLOUD COVER UPSTREAM
OVER CNTRL LK SUPERIOR. THOUGH THE DRYING COULD DIMINISH LES FOR A
TIME OVER WESTERN CWA...ANOTHER SHORTWAVE SEEN UPSTREAM DROPS OVER
THE AREA THIS EVENING. THE SHORTWAVE ALONG WITH THE ARRIVAL OF H85
THERMAL TROUGH WILL LEAD TO INVERSIONS RAISING UP SLIGHTLY AND H925-
H8 MOISTURE PERSISTING. OVERALL THE LOW-LEVEL FLOW WILL VEER MORE
NORTHERLY THIS EVENING BEFORE BECOMING MORE NORTH-NORTHEAST AFTER
MIDNIGHT.

GIVEN THE NORTHERLY FLOW MUCH OF TONIGHT...EXPECT LES TO PERSIST FOR
FAR WESTERN UPR MICHIGAN AND ALSO OVER HIGHER TERRAIN OF NCNTRL CWA.
SOUNDINGS INDICATE THAT ONCE SHORTWAVE AND THERMAL TROUGH ARRIVE
WITH DELTA T/S AROUND 20C...INVERSIONS INCREASE TO 5-6KFT OVER
WESTERN UPR MICHIGAN AND MAINLY TO AROUND 5KFT FOR NCNTRL CWA. THERE
WILL ALSO BE A BIT OF ENHANCEMENT AS WELL DUE TO THE SHORTWAVE THAT
MOVES THROUGH. A FEW MORE INCHES OF SNOW IS POSSIBLE FOR NORTH FLOW
AREAS. OVERNIGHT...LOW-LEVEL WINDS VEER FURTHER TO NNE-NE AS THE
HIGH OVER MANITOBA BEGINS TO BUILD INTO THE REGION. WINDS SHIFTING
SOME AND SUBSIDENCE WILL ALLOW THE LES IN THE WEST TO DIMINISH
OVERNIGHT TONIGHT. CONTINUED WITH WINTER WEATHER ADVISORY THIS
EVENING FOR FAR WESTERN CWA...AND DUE TO THE SLIGHTLY LOWER
INVERSION AND LESS MOISTURE IN THE H9-H8 LAYER...OPTED TO ISSUE AN
SPS FOR MARQUETTE COUNTY. SNOW ALL OVER THE AREA WILL BE FLUFFY AS
MOIST LAYER WITH THE LES WILL BE FIRMLY WITHIN THE DGZ. SLR/S LIKELY
WILL BE WELL OVER 20:1 TONIGHT. TEMPS TONIGHT WILL BE MODIFIED BY
THE WINDS COMING OFF LK SUPERIOR AND ALSO THE LINGERING CLOUD COVER.
EVEN SO...INLAND AREAS OF SOUTHWEST CWA AND ALSO OVER THE EASTERN
CWA MAY SEE READINGS FALL TOWARD ZERO LATE...ESPECIALLY IF THERE IS
ANY CLEARING.

HIGH PRESSURE CENTER ARRIVES IN FULL FORCE ON FRIDAY RESULTING IN
INCREASING SUBSIDENCE/LOWERING INVERSIONS AND LESS LOW-LEVEL
CONVERGENT FLOW. KEPT POPS HIGHER FOR NCNTRL HIGHER TERRAIN ON
FRIDAY MORNING AS EXPECT GOOD COVERAGE TO THE LIGHTER FLUFFIER SNOW
SHOWERS WITH UPSLOPE NNE-N WINDS. NEGATIVE FACTORS WILL KEEP
ADDITIONAL ACCUMULATIONS FOR FRIDAY MAINLY LESS THAN AN INCH. EVEN
AS THERMAL TROUGH DEPARTS...TEMPS WILL REMAIN WELL BLO NORMAL WITH
READINGS IN THE TEENS EAST HALF TO MID-UPR 20S WEST HALF. LESS WIND
THAN TODAY WITH HIGH PRESSURE SETTLING OVERHEAD.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 512 PM EDT THU MAR 26 2015

FAIRLY PROGRESSIVE WEATHER PATTERN SETTING UP OVER THE NRN CONUS
THROUGH MUCH OF THE EXTENDED FCST PERIOD. PERIOD WILL BE
CHARACTERIZED BY VERY COLD NIGHT FRI NIGHT FOLLOWED BY MODERATING
TEMPS ON SATURDAY AS A SHORTWAVE RIDGE BUILDS INTO THE UPPER LAKES.
WEATHER FROM SUNDAY INTO THURSDAY WL THEN BE HIGHLIGHTED BY A
MODERATE AND FAIRLY PROGRESSIVE PACIFIC FLOW WITH NEAR TO ABOVE
NORMAL TEMPS AS A SERIES OF SHORTWAVES MOVE THROUGH THE UPPER GREAT
LAKES BRINGING PERIODS OF MIXED PCPN.

BEGINNING FRI NIGHT...WITH THE SFC HIGH DRIFTING ACROSS THE
AREA...EXPECT A VERY COLD LATE MARCH NIGHT UNDER CALM WINDS AND A
VERY DRY AIR MASS (PRECIPITABLE WATER FCST UNDER ONE-TENTH OF AN
INCH). RECENT ADDITION OF NEW SNOW ON THE GROUND IN MANY AREAS WILL
FURTHER AID RADIATIONAL COOLING. WL FAVOR THE COLDEST END OF AVBL
MODEL GUIDANCE WHICH SUGGESTS MANY INTERIOR LOCATIONS SHOULD FALL
BLO ZERO AND SOME OF THE TRADITIONAL COLDEST SPOTS WL LIKELY FALL
INTO THE DOUBLE DIGITS BLO ZERO. GENERALLY FOLLOWED THE COLDER END
OF 12Z BIAS CORRECTED MODEL GUIDANCE...PARTICULARLY THE CANADIAN
MODEL WHICH TYPICALLY PERFORMS BEST DURING THESE IDEAL RADIATIONAL
COOLING NIGHTS.

SAT WILL BE SUNNY AND WARMER WITH TEMPS MOVING CLOSER TO NORMAL
ESPECIALLY W AND SCNTRL. SOUTHERLY WINDS WILL BEGIN TO INCREASE SAT
AFTERNOON...BUT MORE SO SAT NIGHT DUE TO TIGHTENING PRES GRADIENT
BTWN DEPARTING HIGH SLIDING TO THE SE AND SFC LOW PRES MOVING INTO
SRN MANITOBA/NW ONTARIO. EXPECT DOWNSLOPING AREAS ALONG LAKE
SUPERIOR WEST AND NCNTRL TO GET QUITE GUSTY OVERNIGHT WITH SSW WINDS
REACHING AOA 30 MPH. CONTINUED TO CARRY SLIGHT CHC POPS FOR LATE SAT
NIGHT FOR THE FAR WRN COUNTIES AS BOTH THE FASTER NAM AND GFS SOLNS
STILL HAVE SOME WAA PCPN SNEAKING IN FM WEST AHEAD OF APPROACHING
LOW PRES TROF. ECMWF AND CANADIAN CONTINUE TO BE SLOWER KEEPING THE
WEST DRY THROUGH 12Z SUN.

SUNDAY...THE LOW APPROACHING FM SCNTRL CANADA WILL BE ASSOCIATED
WITH A STRONG SHORTWAVE THAT WILL BE MOVING INTO THE UPPER LAKES.
THE GFS HAS THE DEEPEST SOLN INDICATING 170-200M 12 HR 500 MB HEIGHT
FALLS ACROSS THE AREA ASSOC WITH THE SHORTWAVE. THE
ECMWF/CANADIAN/NAM MODELS ALL KEEP BEST HEIGHT FALLS GENERALLY OVER
NRN LAKE SUPERIOR AND EAST OF UPPER MI. GENERALLY ALL MODELS AGREE
THAT BEST DYNAMICS AND DEEP LAYER Q-VECT CONV ASSOC WITH SHORTWAVE
WILL STAY NORTH OF LAKE SUPERIOR ALONG TRACK OF SFC LOW. STILL A
BRIEF PERIOD OF MODERATE ISENTROPIC ASCENT WILL SUPPORT PCPN
POSSIBLY AS EARLY AS LATE SAT NIGHT FOR WEST BUT MORE LIKELY SUNDAY
FOR MOST OF THE FCST AREA. MIXING RATIOS OF 4G/KG ARE AVBL ON THE
295K SFC (725-750MB)...SO THERE COULD BE A QUICK BURST OF DECENT
SNOWFALL MAINLY IN THE MORNING DURING THE SHORT-LIVED PEAK
ISENTROPIC ASCENT RANGING FROM HALF AN INCH WEST TO 1.5 INCHES EAST
WHERE BEST ISENTROPIC ASCENT IS LOCATED. AFTER THE INITIAL BURST OF
SNOW WITH THE STRONG ISENTROPIC ASCENT...ANY LIGHTER SNOW ESPECIALLY
BY SUN AFTERNOON SHOULD MIX WITH OR EVEN CHANGE TO RAIN FOR A TIME
UNDER DAYTIME HEATING...THEN CHANGE BACK OVER TO SNOW SUN NIGHT
UNDER WEAK CAA.

BIGGER STORY WITH THIS SYSTEM WL LIKELY BE GUSTY WINDS WITH EXPECTED
STRONG PRES FALLS NORTH OF LAKE ENHANCING DOWNSLOPE S-SW WINDS AHEAD
OF THE TROF ALLOWING FOR GUSTS TO REACH NEAR 40 MPH ALONG THE LAKE
SUPERIOR SHORE AND ERN COUNTIES. S-SW WINDS COULD ALSO APPROACH 40
MPH ALONG PORTIONS OF LAKE MI AS WELL AS S-SW WINDS FUNNEL ACROSS
THE LONG AXIS OF THE LAKE. WINDS WILL SHIFT NW BEHIND LATE SUNDAY
INTO SUNDAY NIGHT AND REMAIN FAIRLY GUSTY INTO SUN EVENING.

MAINLY DRY WEATHER WILL FOLLOW FOR MON AS A WEAK HIGH PRES RIDGE
MOVES ACROSS THE AREA. 12Z MODELS HINT AT ANOTHER WEAKER SHORTWAVE
MOVING THROUGH THE REGION MON NIGHT WHICH COULD BRING SOME LIGHT
PCPN TO THE AREA INTO TUE MORNING FOLLOWED BY ANOTHER DRY PERIOD TUE
AFTERNOON INTO TUE NIGHT AS ANOTHER SHORTWAVE RIDGE MOVES IN FM THE
WEST. BOTH THE ECMWF AND GFS INDICATE ANOTHER SHORTWAVE MOVING INTO
THE AREA FOR WED INTO THU AND DEPENDING ON THE TRACK/STRENGTH OF THE
SHORTWAVE THIS COULD BE A BETTER PCPN PRODUCER FOR THE REGION. THERE
WL BE PLENTY OF TIME YET FOR MODELS TO SORT OUT DETAILS/DIFFERENCES
BUT FOR NOW WL INCLUDE CHC POPS ACROSS MUCH OF CWA WED/THU.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1221 AM EDT FRI MAR 27 2015

ALTHOUGH SOME -SHSN WITH MVFR CIGS/VSBYS MAY IMPACT IWD AND SAW
EARLY THIS MRNG...DRYNESS OF UPSTREAM AIRMASS DEPICTED ON THE 00Z
INL AND YPL RAOBS SUGGESTS VFR CONDITIONS WL PREVAIL DESPITE A
FAVORABLE UPSLOPE N WIND IN ADVANCE OF ARCTIC HI PRES MOVING INTO
MN. CMX MAY ALSO SEE SOME -SHSN...BUT WEAKER UPSLOPE N WIND RULES
OUT EVEN A CHC FOR MVFR THERE. THE CLOSER APRCH OF THE DRY HI PRES
WL BRING ABOUT VFR WX AT ALL 3 SITES ON FRI/FRI EVNG...WITH WINDS
TURNING NEAR CALM THIS EVNG AS THE HI SETTLES OVER THE AREA.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 AM EDT FRI MAR 27 2015

THE NEXT STRONG PERIOD OF WINDS LOOKS TO BE LATE SATURDAY NIGHT
THROUGH SUNDAY NIGHT.

WINDS WILL CONTINUE TO WEAKEN AS HIGH PRESSURE CENTERED JUST NW OF
LAKE SUPERIOR THIS MORNING WILL DRIFT SLOWLY SE INTO THE LOWER GREAT
LAKES ON SATURDAY...AND THEN INTO THE MID ATLANTIC STATES ON SUNDAY.
LOOK FOR THE NEXT ROUND OF STRONGER WINDS WITH SW TO W GALES OF
35KTS /POSSIBLY AS HIGH AS 40KTS/ LATE SATURDAY NIGHT THROUGH
SUNDAY.

A LOW TRACKING ACROSS ONTARIO ON SUNDAY WILL DRAG A TROUGH ACROSS
THE UPPER GREAT LAKES. NW GALES TO 35KTS WILL LINGER OVER THE E HALF
OF LAKE SUPERIOR INTO SUNDAY NIGHT. EXPECT A RIDGE TO PASS ACROSS
THE UPPER GREAT LAKES ON MONDAY. ANOTHER LOW WILL THEN TRACK SE
ACROSS THE GREAT LAKES REGION MONDAY NIGHT THROUGH TUESDAY.
&&

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

$$

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



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