Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 191955
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
255 PM EST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM EST FRI DEC 19 2014

A FAIRLY QUIET PATTERN IN THE CENTRAL PART OF THE CONUS...AS THE
SOUTHERN STREAM JET IS SITUATED OVER THE SOUTHERN TIER OF STATES
AND THE SYSTEM THAT BROUGHT SNOW TO THE AREA THIS PAST
TUESDAY/WEDNESDAY IS NOW SPINNING OVER PRINCE EDWARD ISLAND. CLOSER
TO THIS AREA...AN UPPER RIDGE STRETCHES FROM WISCONSIN TO JAMES
BAY...WHILE A UPPER TROUGH IS LOCATED OVER SASKATCHEWAN AND THE
NORTHERN PLAINS. BENEATH THE UPPER RIDGE...1028MB HIGH PRESSURE IS
CENTERED OVER NORTHERN LAKE SUPERIOR WITH A RIDGE STRETCHING SOUTH
THROUGH THE MID MISSISSIPPI VALLEY. THERE IS PLENTY OF DRY AIR ALOFT
ON THE RAP ANALYSIS ASSOCIATED WITH THIS UPPER RIDGE...BUT THE
SUBSIDENCE HAS STRENGTHENED THE INVERSION OVER THE GREAT LAKES AND
UPPER MISSISSIPPI VALLEY REGIONS AND AIDED IN AREAS OF LOW CLOUDS.
THE LARGEST AREA OF LOW CLOUDS COVERS MUCH OF MINNESOTA AND WESTERN
WISCONSIN...WITH THE EASTERN EDGE STRETCHING FROM GRAND MARAIS
MINNESOTA THROUGH IRONWOOD MICHIGAN AND TOWARDS MADISON WISCONSIN.
BUT THERE IS A POCKET OF CLOUDS THAT DEVELOPED OVER SOUTH CENTRAL
LAKE SUPERIOR LATE THIS EVENING (AIDED BY MARGINAL DELTA-T VALUES
FOR LAKE CLOUDS) AND WITH THE LIGHT NORTHERLY FLOW...SHIFTED INTO
THE KEWEENAW AND NORTH CENTRAL U.P.  DEFINITELY HAVE TO GIVE SOME
CREDIT TO THE REGIONAL GEM...WHICH SUPERBLY PICKED UP ON THESE
CLOUDS WITH THE 00Z RUN YESTERDAY. THESE CLOUDS ALLOWED TEMPERATURES
TO QUICKLY RISE AROUND 10 DEGREES AND LOCATIONS UNDER THEM ARE IN
THE MID-UPPER TEENS. ELSEWHERE IN THE U.P. SKIES ARE CLEAR AND WITH
THE LIGHT WINDS...TEMPERATURES HAVE FALLEN INTO THE LOWER SINGLE
DIGITS ABOVE AND BELOW ZERO.

THE UPPER RIDGE AND SURFACE HIGH CURRENTLY OVER THE AREA WILL
SLOWLY SHIFT EAST-SOUTHEAST TODAY AND TONIGHT...ALLOWING THE AREA
TO COME UNDER GREATER INFLUENCE OF THE WEAK UPPER TROUGH. THE LOW
CLOUDS WILL BE THE PRIMARY CONCERN FOR THE FORECAST FOR TODAY. WITH
GENERALLY LIGHT WINDS AND A RELATIVELY LOW SUN ANGLE...GETTING A
HANDLE ON THE LOW CLOUDS OVER THE NORTH CENTRAL AND KEWEENAW IS
DIFFICULT. FOLLOWING 925MB WINDS IN THE MODELS...WOULD EXPECT THEM
TO TRY TO NOSE A LITTLE FARTHER INLAND OVER THE CENTRAL (AND EVEN
THE EASTERN) PART OF THE U.P. TODAY...WHILE THE DEVELOPING LIGHT
SOUTHERLY FLOW WOULD LIKELY PULL DRIER AIR BACK INTO THE KEWEENAW
AND PUSH THOSE CLOUDS NORTH. BUT THAT INCREASING SOUTHERLY FLOW
WILL ALSO PULL THE CLOUDS RIGHT NEAR IRONWOOD INTO THE REST OF
GOGEBIC AND ONTONAGON COUNTIES THROUGH THE DAY TODAY...EVENTUALLY
REACHING IRON/HOUGHTON COUNTIES THIS EVENING AS THE LIMITED MIXING
DECREASES AND THE STRATUS CAN REALLY EXPAND. THESE LOW CLOUDS
(ALONG WITH MID CLOUDS FROM THE WEAK UPPER TROUGH AXIS SHIFTING EAST
INTO MINNESOTA) WILL CONTINUE TO SPREAD ACROSS UPPER MICHIGAN FROM
SOUTHWEST TO NORTHEAST TONIGHT AS SOUTHWESTERLY FLOW GRADUALLY
DEVELOPS.

AS FOR TEMPERATURES...EVEN WITH THE COLD START THIS MORNING IN
SOME LOCATIONS...EXPECT ANOTHER DAY OF HIGHS A LITTLE BIT
ABOVE NORMAL (UPPER 20S TO LOWER 30S). THE LOWS TONIGHT WILL BE
TRICKY...AS THEY DEPEND ON THE LOCATIONS OF THE CLOUD COVER. WHERE
SKIES ARE CLEAR OVER THE CENTRAL AND EAST...WOULD EXPECT ANOTHER
QUICK DROP TO TEMPS IN THE EVENING AND NEARING 0 UNDER LIGHT WINDS.
BUT WHERE THERE ARE CLOUDS...TEMPS WILL STRUGGLE TO FALL INTO THE
MID TEENS. WILL KEEP LOWS UP THE HIGHEST OVER THE FAR WEST...WHERE
THE CLOUDS WILL MOST LIKELY BE LOCATED.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 254 PM EST FRI DEC 19 2014

NAM SHOWS A 500 MB TROUGH OVER THE UPPER GREAT LAKES 00Z SUN WITH A
CLOSED LOW OVER WESTERN ONTARIO WITH A SHORTWAVE OVER THE CANADIAN
PRAIRIES. THIS SHORTWAVE DIGS SOUTHEAST AND FORMS A CLOSED 500 MB
LOW OVER THE UPPER MISSISSIPPI RIVER VALLEY 00Z TUE.

KEPT SAT NIGHT THROUGH SUN MORNING DRY WITH PCPN OFF TO THE WEST AND
NORTHWEST OF THE AREA AND THEN START TO BRING IN SOME SLIGHT CHANCES
FOR SNOW SUN AFTERNOON AND THEN START TO BRING IN SOME CHANCE POPS
FOR SUN NIGHT INTO MONDAY. DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST FOR TEMPERATURES. DID KEEP IN SOME RAIN/SNOW MIX FOR
MONDAY AFTERNOON.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW NEARING THE
UPPER GREAT LAKES 12Z TUE EMBEDDED IN A TROUGH OVER THE PLAINS
STATES. THE TROUGH AND UPPER LOW MOVE SLOWLY EAST 12Z WED AND ARE
EAST OF THE AREA INTO THE LOWER GREAT LAKES 12Z THU FOLLOWED BY
SHORTWAVE RIDGING OVER THE PLAINS. THIS RIDGING MOVES INTO THE UPPER
GREAT LAKES 12Z FRI. THIS SYSTEM FOR MONDAY NIGHT INTO THURSDAY IS
STILL NOT WELL HANDLED BY THE MODELS. THE ECMWF CONTINUES WITH A
FURTHER SOUTH TRACKING OF THE SFC LOW WHICH WOULD GIVE US COLDER AIR
AND MORE SNOW WHILE THE GFS TRACK IS FURTHER NORTH. THERE IS ALSO A
QUESTION OF IF THIS SYSTEM WILL GO FURTHER SOUTH AND EAST AND TURN
INTO AN EAST COAST STORM RATHER THAN A GREAT LAKES STORM. LOOKING AT
THE NEW ECMWF...IT CONTINUES TO GO WITH A GREAT LAKES SYSTEM...BUT
THE 500 MB TROUGH BECOMES VERY NEGATIVELY TILTED. HAVE A FEELING THE
FURTHER SOUTH AND EAST SOLUTION MAY VERIFY WITH THE EAST COAST STORM
THOUGH AND HOPEFULLY LATER MODEL RUNS WILL BE ABLE TO FIGURE THIS
OUT. WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO FOR NOW AS THE PCPN
TYPE AND SNOW AMOUNTS ARE HIGHLY DEPENDENT ON THE TRACK TO THE SFC
LOW AND THERE WILL BE SOME LAKE ENHANCEMENT TO THE SNOW AS WELL.
TEMPERATURES WILL BE ABOVE NORMAL FOR THIS FORECAST PERIOD. BUMPED
UP WINDS IN THE EXTENDED FROM 06Z THU ONWARD AS PRESSURE GRADIENT
TIGHTENS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1246 PM EST FRI DEC 19 2014

EXPECT LITTLE CHANGE THROUGH THE TAF PERIOD AS WARM AIR AND MOISTURE
ADVECTION CONTINUES BETWEEN A HIGH PRESSURE SYSTEM TO THE EAST AND A
TROUGH OVER THE NORTHERN PLAINS. MODELS ARE HAVING TROUBLE
REPRESENTING LOW LEVEL CLOUDS OVER KCMX AND KSAW. MODELS SHOW CLOUDS
MOVING NORTHEAST AND DIMINISHING...BUT CLOUDS HAVE BEEN STEADILY
EXPANDING THIS MORNING. FOR THIS REASON...THERE IS A GOOD AMOUNT OF
UNCERTAINTY WITH CIGS THROUGH THE TAF PERIOD. DO THINK THAT KSAW WILL
SCATTER OUT FOR A TIME THIS EVENING...WHICH MAY ALLOW FOG TO FORM AT
THE SITE. KCMX MAY CLEAR OUT THIS AFTERNOON/EVENING...BUT WAS LESS
CONFIDENT SO DID NOT INCLUDE THAT IN THE TAF.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 AM EST FRI DEC 19 2014

EXPECT LIGHT WINDS UNDER 20 KTS ASSOCIATED WITH HI PRES PASSING THRU
THE UPPER LAKES TODAY TO SHIFT TO THE S BUT REMAIN UNDER 20 KTS
UNTIL AT LEAST SUN. THE S WINDS MAY INCREASE UP TO 25 KTS OVER
MAINLY THE E HALF OF THE LAKE LATER SUN INTO MON IN ADVANCE OF AN
APPROACHING LO PRES. AS ANOTHER LO PRES DEVELOPS TO THE S...THE FLOW
WILL TEND TO BACK AND WEAKEN ON TUE. DEPENDING ON HOW QUICKLY THIS
SECOND LO DEVELOPS AND WHERE IT TRACKS...THERE COULD BE A NW GALE
EVENT ON WED OR XMAS DAY.
&&

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

$$

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





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