Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KMQT 191147
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
647 AM 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 THROUGH THURSDAY)
ISSUED AT 345 AM EST FRI DEC 19 2014

MAIN FCST CONCERNS IN THE MEDIUM/EXTENDED RANGE INCLUDE POPS ON SUN
NGT INTO MON AS A WAA REGIME DEVELOPS IN THE UPR LKS BTWN HI PRES
MOVING INTO NEW ENGLAND AND LO PRES TAKING SHAPE IN THE NRN PLAINS
ASSOCIATED WITH A STRONGER SHRTWV RIDING OVER A RDG ALONG THE W
COAST. THE POTENTIAL FOR A HEAVIER SYNOPTIC THEN LK ENHANCED SN IS
STILL THERE FOR TUE THRU XMAS AS THE DIGGING SHRTWV DEEPENS AN UPR
TROF OVER THE CENTRAL CONUS AND A LO PRES SOMEWHERE IN THE GREAT
LKS. BUT THERE REMAINS SOME INCONSISTENCIES AMONG THE MEDIUM/LONG
RANGE GUIDANCE ON THIS LO AND HOW QUICKLY A SECOND LO WL TAKE
SHAPE...SO CONFIDENCE IS LO ON THE FCST FOR MON THRU XMAS.

SAT/SAT NGT...A SFC HI PRES RDG STRETCHING FM WRN QUEBEC INTO THE
MID MS RIVER VALLEY ON SAT MRNG WILL MOVE SLOWLY TO THE E AND TO
NEAR NEW ENGLAND TO THE OH RIVER VALLEY BY 12Z SUN UNDER LGT W FLOW
ALOFT. A WEAK SHRTWV EMBEDDED IN THIS W FLOW WL BE DRIFTING THRU THE
UPR LKS DURING THIS PERIOD. ALTHOUGH THERE WL BE SOME WAA IN THE SW
FLOW ON THE BACK SIDE OF THE DEPARTING HI AND PVA IN ADVANCE OF THE
SHRTWV...MODELS SHOW ONLY WEAK ISENTROPIC ASCENT/DEEP LYR QVECTOR
CNVGC/UVV IN THE ABSENCE OF SGNFT MSTR INFLOW. SINCE FCST SDNGS
INDICATE LIMITED DEEP SATURATION...WL MAINTAIN GOING DRY FCST AND
MOCLDY SKIES. TEMPS SHOULD RUN ABOVE NORMAL FOR THE SEASON WITH H85
TEMPS NOT FAR FM -5C TO -7C.

SUN/SUN NGT...MOST OF THE MEDIUM RANGE OPERATIONAL MODELS SHOW
ANOTHER MORE COMPACT SHRTWV CROSSING THE UPR LKS ON LATE SUN INTO
EARLY MON ACCOMPANIED BY SOME SHARPER DPVA. IN TANDEM WITH SOME MORE
IMPRESSIVE ISENTROPIC ASCENT IN THE SSW FLOW BTWN THE DEPARTING HI
PRES RDG TO THE E AND FALLING MSLP IN THE NRN PLAINS ASSOCIATED WITH
A STRONGER SHRTWV RIDING THRU THE NRN ROCKIES AND OVER THE UPR RDG
OFF THE W COAST...MODELS DO GENERATE SOME WIDESPREAD ALBEIT LGT PCPN
AT TIMES DURING THIS PERIOD. THE GFS SHOWS A WEAKER SHRTWV/DYNAMIC
FORCING...BUT ENUF ISENTROPIC ASCENT TO GENERATE SOME LGT PCPN AS
WELL. FCST WL SHOW A PERIOD OF UP TO HI CHC POPS TO REFLECT MODEL
DISCREPANCIES ON THE TIMING OF THE STRONGER UVV. SSW FLOW UP THE
LENGTH OF LK MI MAY SUPPORT SOME HIER POPS OVER THE E...BUT MARGINAL
CHILL OF THE AIRMASS FOR LK ENHANCEMENT AND SOME SHEAR SHOULD LIMIT
THE POTENTIAL FOR A SGNFT IMPACT. TEMPS WL REMAIN ABOVE NORMAL...
ESPECIALLY ON SUN NGT WITH CLD COVER AND A STEADY S WIND GREATLY
LIMITING THE DIURNAL TEMP FALL.

MON THRU XMAS DAY...ALTHOUGH THE MEDIUM/LONG RANGE GUIDANCE ARE IN
AGREEMENT AN UPR TROF WL DEEPEN WITH AN H5 LO CLOSING OFF SOMEWHERE
OVER THE CENTRAL CONUS DOWNSTREAM OF THE RDG OVER THE FAR W AND THAT
THE CLOSED LO/UPR TROF WL TAKE ON A NEGATIVE TILT BY LATE TUE/XMAS
EVE...THERE ARE CONSIDERABLE DIFFERENCES ON THE FCST MSLP AND
THERMAL FIELDS. THE 12Z AND 00Z GFS ENSEMBLE SPREAD ON THE FCST LO
POSITION ON TUE/WED WAS QUITE WIDE...REFLECTING THE RATHER POOR
PREDICTABILITY OF THIS PATTERN WITH THE MAIN PLAYERS STILL OUT OVER
THE DATA POOR PACIFIC OCEAN. IN GENERAL...THE GFS IS FARTHER N WITH
THE RESULTING SFC LO AND THUS SHOWS WARMER LLVL TEMPS THAT WOULD BE
SUFFICIENT FOR A GOOD DEAL OF THE PCPN TO FALL AS RA OVER A GOOD
PORTION OF THE CWA. THE 00Z ECWMF ON THE OTHER HAND SHOWS A FARTHER
S TRACK FOR THE SFC LO AND QUICKER REDEVELOPMENT OF A DEEPER SECOND
LO ASSOCIATED WITH THE SHARPLY DIGGING SHRTWV INTO THE TROF THAT ALL
THE MODELS EVENTUALLY LATCH ON TO AS THE MAIN FEATURE. THE 00Z UKMET
IS CLOSER TO THE ECMWF...WHILE THE CNDN IS MORE OF A COMPROMISE.
SINCE BOTH THE GFS/ECWMF HAVE SHOWN CONTINUITY FM PREVIOUS RUNS AND
THERE IS CONSIDERABLE DIFFERENCES...FOLLOWED A MODEL CONSENSUS APRCH
FOR FCST PREPARATION. DID INCREASE POPS ABOVE THE CONSENSUS ON WED/
THU NEAR LK SUP WITH CYC NE UPSLOPE FLOW SHIFTING TO THE NW BY XMAS
TO THE NW OF DEEPENING LO AND DRAWING COLDER AIR INTO THE UPR LKS
THAT WOULD BE SUFFICIENT FOR SOME LK ENHANCEMENT /H85 TEMPS NEAR
-10C ON XMAS/.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 646 AM EST FRI DEC 19 2014

TWO AREAS OF MVFR CEILINGS ARE AFFECTING THE TAF SITES THIS MORNING
AND WILL CONTINUE AT TIMES TODAY AND TONIGHT. AT KIWD...THE EDGE OF
LOW END MVFR CEILINGS HAS BEEN HOVERING OVER THE SITE DURING THE
OVERNIGHT HOURS. WITH LOW LEVEL WINDS STARTING TO INCREASE OUT
OF THE SOUTH...WOULD EXPECT THEM TO PUSH INTO THE SITE SHORTLY AND
CONTINUE THROUGH THE REST OF THE DAY AND INTO TONIGHT.

AT KCMX AND KSAW...MVFR STRATUS PUSHED INTO BOTH SITES LATE
YESTERDAY EVENING. WITH WINDS BECOMING LIGHT TODAY...CONFIDENCE IS
LOW ON THE TIMING OF THEM DEPARTING. THINK THEY WILL DEPART FIRST
AT KCMX WITH SOUTHERLY WINDS DEVELOPING EARLIER AND THERE HAVE BEEN
EASTERLY DOWNSLOPE WINDS OFF THE HURON MOUNTAINS LEADING TO SOME
CLEARING OVER THE KEWEENAW BAY. AT KSAW...THE NORTH-NORTHEASTERLY
FLOW WILL PERSIST THROUGH MUCH OF THE MORNING BEFORE BECOMING
VARIABLE. THAT SHOULD KEEP THE LOW CLOUDS IN THROUGH THE
MORNING...BUT THINK THE SHALLOW NATURE OF THE MOISTURE SHOULD ALLOW
THEM TO BREAK UP THIS AFTERNOON EVEN WITH THE LOW SUN ANGLE. ONCE
THE CLOUDS DEPART...EXPECT VFR CONDITIONS UNTIL THE MVFR CLOUDS
ARRIVE AGAIN FROM THE SOUTHWEST LATE THIS EVENING AND INTO THE
OVERNIGHT HOURS.
&&

.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...KC
AVIATION...SRF
MARINE...KC





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.