Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 281745
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1245 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 THROUGH FRIDAY)
ISSUED AT 351 AM EST SAT FEB 28 2015

MAIN ISSUE THIS FORECAST PERIOD WILL BE WIDESPREAD LIGHT TO MODERATE
SNOWFALL POTENTIAL TUESDAY INTO TUESDAY EVENING WITH CONTINUED
MODERATING TEMPERATURES.

SUNDAY THROUGH MONDAY...A SURFACE TROUGH/WEAK COLD FRONT WILL
CONTINUE TO SHIFT EASTWARD AND PASS THROUGH THE CENTRAL AND EASTERN
PORTIONS OF THE  UPPER PENINSULA THROUGH THE DAY SUNDAY. MOISTURE
WILL BE SHALLOW AND FAIRLY LIMITED ALONG THE FRONT WITH CONTINUED
WEAK FORCING. THIS WILL TOUCH OFF VERY LIGHT SNOW THROUGH THE DAY
SUNDAY. BEHIND THE FRONT...AN UPPER LEVEL 500MB TROUGH IS POISED TO
SWING ACROSS THE U.P. SUNDAY NIGHT. AS THIS HAPPENS...ENOUGH
MOISTURE WILL REMAIN IN PLACE WITH MINIMAL ADDITIONAL MOISTURE ADDED
FROM THE VERY ICE COVERED LAKE SUPERIOR TO ALLOW A CHANCE OF LAKE
EFFECT SNOW SHOWERS TO DEVELOP FOR WEST TO NORTHWEST WIND FAVORED
LOCATIONS. 850MB TEMPERATURES WILL DROP TO AROUND -15C TO -20C
ALLOWING FOR SUFFICIENT DELTA T VALUES FOR LAKE EFFECT WITH THE
TROUGH AXIS SLIDING ACROSS...BUT LAKE EFFECT INTENSITY/COVERAGE WILL
BE LIMITED TO AREAS THAT BREAKS IN THE ICE COVER OCCUR. THIS IS
ESPECIALLY TRUE NOW THAT THE ICE EXTENT ON LAKE SUPERIOR IS AT 95.55
COVERED...WHICH IS THE MAX FOR THE SEASON TO THIS POINT. ANY LAKE
EFFECT THAT IS ABLE TO DEVELOP SUNDAY NIGHT WILL BE SHORT LIVED AS
MUCH DRIER AIR AND HIGH PRESSURE AT THE SURFACE AND RIDGING ALOFT
PUSH INTO THE UPPER GREAT LAKES REGION DURING THE DAY MONDAY. THIS
WILL ALL MOST AREAS TO SEE MAINLY SUNNY SKIES DURING THE DAY MONDAY
WITH HIGHS IN THE 20S FOR MOST AREAS. THIS IS STILL BE AROUND 5 TO
10 DEGREES BELOW NORMAL...BUT IT WILL DEFINITELY BE WARMER THAN THE
LAST SEVERAL WEEKS.

MONDAY NIGHT THROUGH TUESDAY NIGHT...THE SURFACE HIGH PRESSURE
SYSTEM WILL BE SHORT LIVED AND WILL SHIFT TO THE LOWER GREAT LAKES
THROUGH MONDAY EVENING...THEN TO THE EASTERN SEABOARD LATE MONDAY
NIGHT. THIS WILL ALLOW A MORE MOIST...SLIGHTLY WARMER...SOUTHERLY
FLOW TO DEVELOP ON THE BACK SIDE OF THE HIGH.  AT THE SAME TIME...A
SURFACE LOW PRESSURE SYSTEM IS PROGGED TO DEVELOP ALONG A SHORTWAVE
OVER THE FOUR CORNERS REGION OF THE CONUS. ANOTHER STRONGER WAVE OF
ENERGY IS PROGGED TO PUSH ACROSS CENTRAL CANADA AND WORK TOWARD THE
JAMES BAY AREA. MODEL DIFFERENCES CONTINUE WITH THE PHASING OF THE
TWO SYSTEMS. THE 18Z/27 00Z/28 GFS CONTINUES TO BE MORE PROGRESSIVE
WITH BOTH SYSTEMS AND THE PHASING OF THE SYSTEMS.
ADDITIONALLY...THE GFS INTENSIFIES THE SOUTHERN SYSTEM MORE
AGGRESSIVELY THAN THE LAST TWO RUNS OF THE EC. EVEN THOUGH IT IS
MORE PROGRESSIVE OVERALL...THE LATEST RUNS OF THE GFS ARE SLOWER
WITH BRINGING PRECIP INTO THE AREA THAN IT HAS BEEN OVER THE
PREVIOUS DAYS RUNS...MORE IN LINE WITH THE EC. THE EC 12/27 00Z/28
CONTINUES TO BE MUCH SLOWER WITH THE PHASING...KEEPING THE
PRECIPITATION OUT OF THE AREA UNTIL VERY LATE MONDAY NIGHT INTO
TUESDAY MORNING. THE OVERALL IMPACT...AS FAR AS SNOWFALL
AMOUNTS...WILL LARGELY DEPEND ON HOW AND WHEN THESE SYSTEM MERGE.
EITHER WAY...IT DOES LOOK LIKE MOST OF THE U.P. WILL SEE WIDESPREAD
SNOWFALL THROUGH THE DAY TUESDAY INTO TUESDAY EVENING...WITH THE
HEAVIER SNOWFALL TOTALS EXPECTED ACROSS SOUTH CENTRAL AND THE EAST
HALF OF THE U.P. MODELS AGREE WITH QPF BEING PAINTED OUT ACROSS
THESE AREAS TO THE POINT THAT LIKELY POPS ARE IN ORDER ESPECIALLY
TUESDAY AFTERNOON INTO TUESDAY EVENING
...AGAIN THE AMOUNTS ARE THE MAIN QUESTION AT THIS POINT WITH THE
GFS PLACING AROUND A HALF INCH QPF ACROSS THE AREA AND THE EC
PAINTING AROUND A QUARTER INCH. THIS WOULD GIVE SNOWFALL TOTALS OF
AROUND 1 TO 3 INCHES OVER THE WEST HALF WITH AROUND 2 TO 5 INCHES
OVER THE EAST HALF...AGAIN THESE ARE PRELIMINARY ESTIMATES AND WILL
BE ADJUSTED AS MODELS BEGIN TO COME INTO BETTER AGREEMENT WITH
BETTER SAMPLING OVER TIME. THE FORTUNATE ASPECT OF THIS SYSTEM IS
THAT IT IS FAIRLY QUICK MOVING...WHICH SHOULD HELP TO KEEP SNOWFALL
TOTALS IN CHECK...BUT IT COULD BE SOMEWHAT OF A HASSLE AS THE
HEAVIER SNOW WOULD FALL DURING THE TUESDAY AFTERNOON/EVENING COMMUTE.

WEDNESDAY THROUGH THE REMAINING EXTENDED...BOTH THE EC AND GFS AGREE
ON AN UPPER LEVEL TROUGH AXIS ALONG WITH CONTINUED MOISTURE ACROSS
THE AREA DURING THIS TIME PERIOD. THE COLDER TEMPERATURES ALOFT
ALONG WITH ANY ADDITIONAL MOISTURE OFF LAKE SUPERIOR WILL ALLOW FOR
LAKE EFFECT SNOW CHANCES ACROSS PORTIONS OF THE U.P...ESPECIALLY
THROUGH THURSDAY. AGAIN...THE EXACT LOCATION ALONG WITH INTENSITY
WILL BE LARGELY TIED TO ANY BREAKS IN THE ICE COVER ON LAKE
SUPERIOR. THE FAVORED LOCATIONS BASED SOLELY ON WIND WOULD BE FOR
THE WEST TO WEST NORTHWEST WIND FAVORED SNOW BELTS WITH A SURFACE
HIGH PRESSURE SYSTEM PASSING TO THE SOUTH OF THE REGION.
GENERALLY...ANY LAKE EFFECT SNOW SHOULD REMAIN FAIRLY LIGHT...BUT
THIS WILL DEPEND ON ANY BREAKS IN THE ICE ON LAKE SUPERIOR. THURSDAY
NIGHT...THE SURFACE HIGH WILL SHIFT TO THE EAST OF THE AREA AS A
SURFACE TROUGH APPROACHES THE U.P. FROM THE WEST. THIS WILL
EFFECTIVELY TURN WINDS SOUTH TO SOUTHWESTERLY...ENDING ANY LAKE
EFFECT SNOW CHANCES ACROSS THE U.P.
&&

.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 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 351 AM EST SAT FEB 28 2015

NO GALES EXPECTED INTO NEXT WEEK...WITH WINDS NO HIGHER THAN 20 TO
25 KTS. LAKE SUPERIOR REMAINS MOSTLY ICE COVERED AND THOUGH SHIFTING
WINDS WITH A SERIES OF TROUGH PASSAGES MAY CAUSE HOLES TO OPEN IN
THE ICE FROM TIME TO TIME...A CONTINUED DOMINANCE OF ARCTIC AIR WILL
MAINTAIN AN OVERALL EXTENSIVE ICE COVER.
&&

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

$$

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


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