Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 281959
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
259 PM EST SAT FEB 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM EST SAT FEB 28 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A MORE SPLIT FLOW
OVER NAMERICA WITH UPR MI ON THE SRN FLANK OF A WNW FLOW ON THE SW
FLANK OF ARCTIC BRANCH CLOSED LO DRIFTING OFF THE NEWFOUNDLAND
COAST. SHRTWV RDG APRCHG THRU MN/VERY DRY AIR SHOWN ON LOCAL 00Z
RAOBS /00Z PWATS WERE ARND 0.07 INCH OR 30-35 PCT OF NORMAL/ ARE
RESULTING IN MOCLR SKIES EARLY THIS MRNG. DESPITE DRYNESS OF THIS
AIRMASS AND CHILL WITH 00Z H85 TEMPS IN THE -16 TO -17C RANGE...
STEADY WSW FLOW UNDER THE RATHER TIGHT PRES GRADIENT TO THE N OF HI
CENTER IN THE OH RIVER VALLEY HAS RESTRICTED THE DROP IN TEMP OVER
MUCH OF THE CWA...ESPECIALLY AT THE MORE EXPOSED LOCATIONS NEAR THE
LAKES...WHERE CURRENT TEMPS RANGE FM ZERO TO 10 ABOVE. BUT SOME OF
THE SHELTERED INTERIOR LOCATIONS HAVE SEEN THE MERCURY FALL TO AS LO
AS -15F TO -20F. LOOKING UPSTREAM...HI CLDS ARE STREAMING INTO MN IN
ADVANCE OF A SHRTWV MOVING E INTO NDAKOTA. BUT SINCE THE AIRMASS IN
THE NRN PLAINS IS ALSO QUITE DRY /AREA PWATS ARE UNDER 0.10 INCH AND
THE 00Z H85 AND H7 DEWPT DEPRESSIONS AT BISMARCK WERE 19C AND 30C
RESPECTIVELY/...THERE IS AN ABSENCE OF PCPN ACCOMPANYING THIS
DISTURBANCE.

MAIN FCST CONCERNS IN THE SHORT TERM WL FOCUS ON MAX TEMPS TODAY AND
IMPACT TNGT OF SHRTWV NOW MOVING THRU THE NRN PLAINS.

TODAY...SHRTWV RDG AXIS NOW IN MN IS PROGGED TO PASS THRU THE CWA
THIS AFTN. ACCOMPANYING AREA OF H85-5 RH UNDER 20 PCT WL RESULT IN
SUNSHINE FILTERED AT TIMES BY SOME HI CLDS STREAMING INTO THE AREA
IN ADVANCE OF SHRTWV THAT IS FCST TO REACH NW MN BY 00Z SUN. AS H85
TEMPS REBOUND TO ARND -14C IN THE SW FLOW ARND SFC HI PRES SHIFTING
TOWARD THE MID ATLANTIC STATES...EXPECT MAX TEMPS TO TOP OUT A
COUPLE OF DEGREES HIER THAN OBSVD YDAY...PERHAPS UP TO 25 IN THE
DOWNSLOPE AREAS NEAR LK SUP BTWN MARQUETTE AND BARAGA. THE LOWEST
TEMPS IN THE TEENS ARE LIKELY DOWNWIND OF THE ICE COVERED NRN BAY OF
GREEN BAY/LK MI.

TNGT...SHRTWV OVER NW MN IS PROGGED TO SHIFT E ACROSS NRN LK SUP AND
INTO ONTARIO JUST E OF THE LK BY 12Z ON SUN. SOME DPVA/MODEST DEEP
LYR QVECTOR CNVGC IS FCST TO INFLUENCE UPR MI AHEAD OF THE SHRTWV.
BUT MODEST MSTR INFLOW/ISENTROPIC ASCENT INTO ANTECEDENT BONE DRY
AIRMASS WL GREATLY RESTRICT POPS. IN FACT...MOST OF THE MODELS
INDICATE A MAINLY DRY OVERNGT AND GENERATE ONLY PATCHY LIGHT PCPN.
SEEMS THE BEST CHC FOR PCPN WL BE OVER LK SUP AND PERHAPS DOWNWIND
OF LK MI FM MANISTIQUE TO NEWBERRY. WL RETAIN MENTION OF SCHC
POPS...MAINLY OVERNGT. LO TEMPS TNGT COULD BE TRICKY WITH LINGERING
DRY AIR IN PLACE BEFORE THICKER CLDS ARRIVE. TENDED TO GO HIER WITH
MIN TEMPS IN THE DOWNSLOPE AREAS NEAR LK SUP IN PREVAILING SSW FLOW.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 259 PM EST SAT FEB 28 2015

GOOD AGREEMENT FM THE MODELS ON OVERALL LOOK OF LARGE SCALE PATTERN
THROUGH THE EXTENDED. TROUGH AND COLD AIR THAT HAS DOMINATED FOR
FEBRUARY EASES FIRST PART OF THE WEEK. JUST BEFORE THAT OCCURS THERE
COULD BE SOME LIGHT LAKE EFFECT SNOW SHOWERS SUNDAY NIGHT FOR AREAS
FAVORED BY WNW WINDS. SOUNDINGS INDICATE INVERSIONS UP TO 5KFT WITH
A LOT OF THE MOIST LAYER IN THE DGZ. LACK OF OPEN WATER WILL HAMPER
THE LES...BUT WILL CARRY SCATTERED POPS FOR SNOW BELTS EAST OF MQT
AND P53. LES COULD LINGER AS FLURRIES ON MONDAY MORNING...BUT WILL
OPT FOR DRY FORECAST AS HIGH PRESSURE RIDGE SHOULD BE PUTTING AN END
TO THE LES. WITH A NW LOW-LEVEL FLOW...MODELS HANG ON TO LOW CLOUDS
PROBABLY ENHANCED DUE TO DAYTIME HEATING. MODELS MAY BE OVERDOING
LOW-LEVEL RH THOUGH...SO WILL JUST GO PARTLY CLOUDY FOR DAYTIME ON
MONDAY. HIGHS BOUNCE UP INTO THE 20S...THOUGH WILL REMAIN ONLY TO
AROUND 20 OVER EAST WITH LINGERING NW WINDS OFF ICE OF LK SUPERIOR
MOST OF THE DAY.

CLOUDS THICKEN ON MONDAY NIGHT AHEAD OF DOUBLE BARRELLED LOW
PRESSURE SYSTEM THAT MOVES OVER THE REGION ON TUESDAY. TEMPS MAY
FALL QUICKLY OVER THE EAST CWA ON MONDAY NIGHT...BUT WILL BE IN THE
TEENS ELSEWHERE. ON TUESDAY...NORTHERN STREAM LOW IS THE ONE
AFFECTING ALASKA THIS AFTN AND THE SOUTHERN STREAM LOW IS FORECAST
TO EMERGE OUT OF GENERAL TROUGHING CURRENTLY OVER THE SOUTHWEST
CONUS. H85-H7/H7-H5 Q-VECTOR CONVERGENCE AND MOISTURE ADVECTION
AHEAD OF SFC-H85 TROUGHS WITH H7 MIXING RATIOS 2-3 G/KG SUPPORT
POTENTIAL FOR MODERATE SNOWFALL OVER EAST HALF OF UPR MICHIGAN.
BLEND OF QPF ALONG WITH EXPECTED SLR/S IN THE 13-18:1 RANGE POINT TO
SNOWFALL RANGING FM 2-4 INCHES/3-5 INCHES. KIND OF SEEMS THAT THERE
MAY BE TWO MAIN TIMES OF SNOW WITH THE SYSTEM...LATE MONDAY NIGHT
INTO TUESDAY MORNING...THEN AGAIN TUESDAY AFTN INTO EARLY TUESDAY
EVENING. MODELS ARE LOCKED IN THAT THE TUESDAY AFTN AND TUESDAY
EVENING TIME FRAME WILL FEATURE THE HEAVIEST SNOW...POSSIBLY WITH
SNOWFALL RATES AROUND 1 INCH PER HOUR. IMPACT COULD BE ON THE HIGHER
SIDE TOO AS THE HEAVIEST SNOW COULD FALL DURING THE AFTN AND EVENING
COMMUTE. WILL CONTINUE TO MENTION IN THE HWO AND EHWO GRAPHICS.

REPRIEVE IN THE COLD AIR IS BRIEF AS MORE COLD AIR...CURRENTLY
UPSTREAM OF THE LOW PRESSURE SYSTEM OVER ALASKA...CHARGES IN LATE
TUESDAY NIGHT INTO WEDNESDAY AND LINGERS THROUGH LATE WEEK. RETURN
OF THE COLD WITH H85 TEMPS BLO -20C WILL LEAD TO LAKE EFFECT FOR NW
FLOW AREAS. SOUNDINGS SHOW INVERSIONS START OUT AT 5KFT ON TUESDAY
NIGHT OVER EASTERN LK SUPERIOR BUT RISE UP TO 8KFT ON WEDNESDAY.
EXTENT OF OVER-WATER INSTABILITY AND DEPTH OF THE CONVECTIVE LAYER
SUGGESTS LOCALLY MODERATE SNOW SHOWERS WILL BE POSSIBLE FOR MAINLY
WNW-NW FLOW AREAS. OVERALL THE LOW VSBY WITH SMALLER SNOWFLAKES WILL
BE THE LARGER IMPACT. WINDS 25-30 KTS SO MAY ALSO HAVE BLSN ALONG
THE SHORE...ESPECIALLY IN THE SNOW BELTS EAST OF MQT. WITH ENOUGH
MOISTURE INLAND ON WEDNESDAY...MAY ALSO SEE DIURNALLY ENHANCED SNOW
SHOWERS WITH PERIODS OF GUSTY WINDS/LOWER VSBY. WINDS BACK W-WSW ON
WEDNESDAY NIGHT WHICH WILL END THE LES ALONG MOST OF LK SUPERIOR.
TEMPS INLAND WILL FALL OFF WELL BLO ZERO. WINDS WILL BE ON THE
DECLINE BUT MAY STILL BE STRONG ENOUGH TO PRODUCE NEAR ADVISORY WIND
CHILLS THURSDAY MORNING OVER PARTS OF THE CWA.

HIGH PRESSURE BUILDING OVER THE NORTHERN PLAINS BY THURSDAY SLIDES
TO THE OHIO VALLEY INTO FRIDAY AS LOW PRESSURE SYSTEM CROSSING
NORTHERN ONTARIO PUSHES A WARM FRONT ACROSS THE UPPER GREAT LAKES.
MID-LEVEL MOISTURE H85-H7 AND WEAK LIFT MAY TRIGGER A FEW SNOW
SHOWERS OR FLURRIES THURSDAY NIGHT INTO FRIDAY MORNING. GFS AND
ECMWF BOTH SHOW MAIN FORCING STAYING OVER LK SUPERIOR AND TO THE
NORTH. ANOTHER COLD FRONT WORKS THROUGH ON FRIDAY NIGHT WITH MORE
COLD AIR SETTLING OVER THE AREA BY NEXT SUNDAY.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM EST SAT FEB 28 2015

A DRY SW FLOW AROUND HIGH PRES SHIFTING TOWARD THE MID ATLANTIC
STATES WILL BRING VFR CONDITIONS TO KIWD/KCMX/KSAW THRU THIS FCST
PERIOD. SOME THICKER CLOUDS WILL ARRIVE TONIGHT IN ADVANCE OF AN
APPROACHING LOW PRES TROF...BUT THE LOW-LEVELS SHOULD REMAIN DRY
ENOUGH TO MAINTAIN VFR CIGS EVEN IF THERE IS SOME VERY LIGHT SNOW OR
FLURRIES. GUSTIER W WINDS WILL DEVELOP LATE SUN MORNING/EARLY AFTN
AT KCMX AFTER SFC TROF PASSAGE.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 259 PM EST SAT FEB 28 2015

NO GALES EXPECTED INTO NEXT WEEK. WSW WINDS TO 30 KTS EXPECTED ON
SUNDAY OVER WESTERN HALF OF LK SUPERIOR WITH NW WINDS TO 30 KTS
TUESDAY NIGHT INTO WEDNESDAY OVER THE EASTERN HALF OF LK SUPERIOR IN
WAKE OF A STRONGER LOW PRESSURE SYSTEM AND COLD FRONT THAT CROSS THE
UPPER GREAT LAKES ON TUESDAY. OTHERWISE...WINDS WILL BE 20 TO 25 KTS
THROUGH THE WEEK. THE STRONG WINDS WILL LIKELY ALTER THE COVERAGE OF
THE ICE SOMEWHAT ON LK SUPERIOR...BUT IN GENERAL EXPECT THE HIGHER
COVERAGE TO PERSIST AS DESPITE SOME WARMING...TEMPERATURES WILL STAY
BELOW FREEZING.
&&

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

$$

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



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