Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 010908
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
408 AM EST SUN MAR 1 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EST SUN MAR 1 2015

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF EXTENDING
FM HUDSON BAY INTO THE NRN PLAINS. TWO SHRTWVS OF NOTE ARE EMBEDDED
IN THIS TROF THAT WL BE OF CONCERN FOR THE FCST. THE FIRST IS MOVING
ALONG THE MN/ONTARIO BORDER EARLY THIS MRNG. ALTHOUGH THE COLDER CLD
TOPS ARE CONFINED TO ONTARIO...SOME LOCATIONS IN MN WITHIN THE
RELATIVELY POORLY DEFINED COMMA TAIL ARE PICKING UP SOME LIGHT
SN/FLURRIES. THE MAIN LIMITING FACTOR FOR MORE PCPN/ENHANCED CLDS IS
ONLY MODEST ISENTROPIC ASCENT BEST SHOWN ON THE 280K SFC/DEEP LYR
QVECTOR CNVGC AND ABSENCE OF DEEP MSTR PER THE 00Z INL/MPX RAOBS.
MID CLDS IN ADVANCE OF THE SHRTWV HAVE INVADED THE CWA...LIMITING
THE DIURNAL FALL OF TEMP IN THE STEADY SW FLOW AHEAD OF THE
ASSOCIATED SFC LO PRES TROF MOVING THRU MN. SOME LIGHT SN HAS ALSO
DVLPD OVER THE ERN CWA WITH SSW FLOW OFF LK MI. LOOKING FARTHER
UPSTREAM...A SECOND SHRTWV IS DIGGING SEWD FM SASKATCHEWAN INTO THE
NRN PLAINS. THERE IS AN AREA OF CLD COVER ASSOCIATED WITH THIS
FEATURE...AND A FEW LOCATIONS ARE REPORTING SOME LIGHT SN.

MAIN FCST CONCERNS THRU TNGT WL FOCUS ON POPS ASSOCIATED WITH THE
TWO SHRTWVS AS WELL AS LES POTENTIAL TNGT IN THE CAA FOLLOWING THESE
DISTURBANCES.

TODAY...FIRST SHRTWV IS FCST TO CONTINUE EWD ACROSS NRN LK SUP THIS
MRNG. MAINTAINED SOME LO CHC POPS THIS MRNG OVER MAINLY THE W AND N
PORTION OF THE CWA CLOSER TO THE SHRTWV TRACK AND AREA OF COLDER CLD
TOPS/HIER H85-5 RH. THERE WL BE ANOTHER CHC OF SOME SN THIS AFTN
OVER MAINLY THE E HALF OF THE CWA WHEN THE ARRIVAL OF SOME SHARPER
PVA/DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE TRAILING SHRTWV WL
ARRIVE COINCIDENTALLY WITH THE SFC TROF. ALTHOUGH WRN LK SUP REMAINS
MOSTLY ICE COVERED...ARRIVAL OF SOME DEEPER MSTR ACCOMPANYING THE
SECOND SHRTWV AND COLDER AIR /H85 TEMPS FALLING NEAR -16C BY 00Z
MON/ IN THE WNW H925 FLOW BEHIND THE TROF WL BRING ABOUT A CHC FOR
SOME SN SHOWERS LATER IN THE DAY OVER THE W AS WELL. WITH A SW
VEERING W FLOW DVLPG THIS AFTN...EXPECT THE HIEST MAX TEMPS IN THE
25 TO 30 RANGE OVER THE DOWNSLOPE AREA OF THE CENTRAL...WHERE THERE
WL BE MORE IN THE WAY OF SOME BREAKS OF SUNSHINE AS WELL.

TNGT...NW FLOW OF COLDER AIR...WITH TEMPS WITHIN TRAILING H85
THERMAL TROF FCST AS LO AS -18C...FOLLOWING THE EXITING SFC TROF WL
RESULT IN SOME LK EFFECT SN SHOWERS MAINLY IN THE NW WIND SN BELTS
DESPITE THE OVERALL ICE COVER. THE BEST CHC FOR THESE SN SHOWERS WL
BE E OF MARQUETTE WITH A LONGER FETCH LENGTH OVER THE MAINLY ICE
COVERED LK. ARRIVAL OF MORE ACYC FLOW IN ADVANCE OF SFC HI PRES RDG
MOVING INTO MN AND SHARPLY LOWERING INVRN AOB 3K FT AGL ASSOCIATED
WITH STRONG SUBSIDENCE ACCOMPANYING VIGOROUS DNVA/06Z-12Z H5 HGT
RISES UP TO 100M AHEAD OF APRCHG SHRTWV RDG AXIS SHOULD END THE LES
OVER THE W LATE. LLVL DRYING/CLRG WL ALLOW TEMPS TO DIP AT LEAST
CLOSE TO ZERO OVER THE INTERIOR W CLOSER TO THE INCOMING SFC HI
PRES...WHICH SHOULD CAUSE THE STEADY WINDS TO DIMINISH A BIT LATE IN
THAT AREA.

.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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1152 PM EST SAT FEB 28 2015

A DRY SW FLOW AROUND HIGH PRES SHIFTING TOWARD THE MID ATLANTIC
STATES SHOULD 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 AT KIWD AND KCMX. GUSTIER W WINDS WILL DEVELOP LATE SUN
MORNING/EARLY AFTN AT KCMX AFTER SFC TROF PASSAGE BUT THEN WIND GUSTS
SHOULD DIE DOWN SUN EVENING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 AM EST SUN MAR 1 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...VOSS
MARINE...KC



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