Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 212010
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
410 PM EDT MON APR 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 424 AM EDT MON APR 21 2014

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW
REGIME ACRS THE CONUS WITH A STRONGER W-E POLAR BRANCH FLOW NEAR THE
CNDN BORDER TO THE N OF A WEAKER SRN BRANCH OVER THE SCENTRAL
STATES. SHRTWV RDG EMBEDDED IN THE POLAR BRANCH AND OVER NE MN/NW
ONTARIO AS WELL AS VERY DRY AIR SHOWN ON THE 00Z INL/MPX RAOBS ARE
BRINGING DRY WX TO UPR MI THIS MRNG EXCEPT OVER FAR SRN MENOMINEE
COUNTY...WHERE SOME ISOLD -SHRA ARE STILL PRESENT ON THE NRN EDGE OF
RIBBON OF DEEPER MSTR STRUNG W-E THRU THE CENTRAL LKS AND SAMPLED BY
THE FAIRLY MOIST 00Z GRB RAOB. MORE WDSPRD SHRA/EMBEDDED TS ARE
PRESENT OVER SW WI/FAR SE MN UNDER DEEPER MSTR/SOME UPR DVGC AHEAD
OF DISTURBANCE ON THE NRN EDGE OF SRN BRANCH FLOW. ALTHOUGH COLDER
CLOUD TOPS ARE EXPANDING TOWARD THE WI BORDER TO THE NE OF THESE
SHOWERS...THE LOWER LVL W FLOW OF VERY DRY AIR FM THE DIRECTION OF
MPX IS LIMITING THE N SPREAD OF THE SHRA LOCATED JUST S OF THAT RAOB
SITE. OTRW...SOME LOCALLY DENSE FOG HAS FORMED OVER THE CENTRAL/ERN
CWA AS THE DRIER AIR ALOFT MOVED OVER LOCATIONS THAT DID NOT SEE
SGNFT LLVL DRYING YDAY AFTN. OVER THE W WHERE SFC DEWPTS MIXED OUT
AS LO AS 25-30 AT IWD ON SUN AND TEMPS ARE STILL ABV 32 AT MOST
SPOTS...THERE IS LTL IF ANY FOG. A MUCH STRONGER SHRTWV IN THE POLAR
BRANCH FLOW IS NEAR LK WINNIPEG AND MOVING STEADILY TO THE E. THERE
HAVE BEEN SOME SHOWERS AND EVEN SOME LGT STRIKES IN MANITOBA RIGHT
UNDER THE STEEPER LAPSE RATES CLOSE TO THE CORE OF THIS DISTURBANCE.
BUT SINCE THIS SHRTWV IS CUTOFF FM THE MOISTER AIRMASS TO THE S...
THERE IS ONLY A NARROW BAND OF LIGHT SHOWERS ALONG ITS ATTENDANT
COLD FNT MOVING THRU NW MN EARLY THIS MRNG.

MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE FOG EARLY THIS MRNG AND
THEN PCPN CHCS LATER TODAY/TNGT AS POLAR BRANCH SHRTWV/ATTENDANT
COLD FNT IMPACT UPR MI.

TODAY...EXPECT LOCALLY DENSE FOG TO PERSIST EARLY THIS MRNG OVER THE
SE HALF OF THE CWA...BUT INCRSG HI CLDS SHOULD LIMIT THE POTENTIAL
FOR WDSPRD DENSE FOG. WL ISSUE AN SPS TO ALERT THE PUBLIC TO LOCALLY
REDUCED VSBYS. SHRTWV NEAR LK WINNIPEG IS FCST TO MOVE E THRU NW
ONTARIO AND DRAG IT ATTENDANT COLD FNT ACRS UPR MI THIS AFTN. SINCE
BULK OF DPVA/DEEP LYR QVECTOR CNVGC WL REMAIN TO THE N AND JUST
BRUSH THE NRN LAND CWA...SUSPECT ONLY ISOLD-SCT SHOWERS WL ACCOMPANY
THE FROPA. ALMOST ALL THE MODELS THAT WERE SHOWING A GREATER
INTERACTION BTWN THIS SHRTWV/DEEPER MSTR TO THE S AND SGNFT
EXPANSION OF THIS MSTR/SHOWERS INTO UPR MI HAVE RETREATED A BIT FM
THIS FCST...A REASONABLE TREND CONSIDERING THE VERY DRY NATURE OF
THE 00Z MPX RAOB AND LACK OF SGNFT BACKING OF THE UPR FLOW FM THE W
THRU THE DAY. THE 00Z HI RES CNDN MODEL SHOWS THE HEAVIER PCPN
OVERSPREADING MOST OF UPR MI ALONG WITH THE MOST UNSTABLE MIXED LYR
CAPES AOA 1000 J/KG. FCST SDNGS FM THIS MODEL SHOW FAIRLY IMPRESSIVE
MOISTENING THRU THE LOWER TROP WITH SFC DEWPTS RISING TO ARND
55...WHICH DOES NOT SEEM RSNBL IN THE ABSENCE OF A DEEPER SW FLOW.
THE 00Z NAM SHOWS MORE MODEST MOISTENING/DESTABILIZATION OVER THE
SCENTRL. WL CARRY THE HIER CHC POPS THIS AFTN WHERE THIS MODEL SHOWS
THE GREATER INSTABILITY UP TO 700-800 J/KG OVER THE SCNTRL. INCLUDED
A SCHC OF TS IN THIS AREA AS WELL GIVEN ARRIVAL OF COLD FNT DURING
PEAK HEATING TIME THAT WL PUSH TEMPS WELL ABV NORMAL AGAIN IN THE
PRESENCE OF H85 TEMPS NOT FAR FM 10C AND AWAY FM THE MODERATING
INFLUENCE OF THE LKS. COOLER AIR WL ARRIVE OVER THE W LATER IN THE
DAY FOLLOWING THE FROPA.

TNGT...NW FLOW WITH H925 WINDS UP TO 25-35 KTS IN THE WAKE OF THE
COLD FROPA WL DRIVE COLDER AIR BACK INTO THE UPR LKS TNGT. MODELS
SHOW H85 TEMPS SINKING AS LO AS -7 TO -8C OVER THE W BY 12Z TUE.
WHILE THIS INCOMING AIRMASS WL NOT BE COLD ENUF FOR LK EFFECT
PCPN...MODELS DO SHOW SOME LLVL MOISTENING BLO STRENGTHENING
SUBSIDENCE INVRN ARND H85 UNDER THE LARGE SCALE QVECTOR DVGC LEFT IN
THE WAKE OF DEPARTING SHRTWV. GOING FCST SHOWS SOME DRIZZLE/FRZG
DRIZZLE OVER THE HIER TERRAIN WITH MOISTENING/INVRN BASE BLO THE
DGZ. THIS FCST SEEMS RSNBL...BUT DID ADD SOME FLURRIES AS WELL.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 409 PM EDT MON APR 21 2014

HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION ON TUESDAY
WILL LEAD TO A DRY PERIOD FOR TUESDAY NIGHT AND MUCH OF WEDNESDAY.
THERE MAY BE A FEW LINGERING CLOUDS OVER THE FAR EAST TO START THE
EVENING...BUT OTHERWISE EXPECT MOSTLY CLEAR SKIES TUESDAY NIGHT AND
INTO WEDNESDAY ACROSS THE U.P. LOWS ON TUESDAY NIGHT WILL BE BELOW
NORMAL AND IN THE 20S FOR MOST LOCATIONS. DID TREND SOME OF THE
INTERIOR COLD SPOTS IN THE TEENS SINCE THE HIGH WILL BE OVERHEAD
AND PWATS OF 40-45 PERCENT OF NORMAL WOULD SUPPORT GOING AT OR
BELOW MOS GUIDANCE. THE APRIL SUNSHINE SHOULD HELP WARM TEMPS BACK
CLOSER TO NORMAL FOR WEDNESDAY. LIGHT WINDS WILL GRADUALLY TURN TO
THE SOUTHEAST DURING THE AFTERNOON...BUT THEY SHOULD BE LIGHT
ENOUGH TO ALLOW LAKE BREEZES TO DEVELOP NEAR THE GREAT LAKES
SHORELINES AND KEEP TEMPERATURES COOLER THERE.

THE BULK OF THE LONG TERM FORECAST DEALS WITH AN UPPER LEVEL TROUGH
AND ASSOCIATED LOW PRESSURE SYSTEM THAT MOVES THROUGH THE GREAT
LAKES REGION WEDNESDAY NIGHT AND LIKELY CONTINUING INTO SATURDAY.
THIS UPPER TROUGH IS CURRENTLY WEST OF THE PACIFIC NORTHWEST AND
WILL COME ONSHORE TONIGHT. AS THIS SYSTEM CROSSES THE ROCKIES...A
SURFACE LOW WILL DEVELOP IN THE LEE OF THE CANADIAN/NORTHERN
ROCKIES AND SHIFT EAST INTO THE UPPER MISSISSIPPI VALLEY ON
THURSDAY. AS THIS OCCURS...BROAD ISENTROPIC ASCENT ON THE 290-305K
SURFACES WILL SPREAD NORTHEAST INTO UPPER MICHIGAN ON WEDNESDAY
NIGHT. THIS FIRST WAVE WILL STEADILY PUSH NORTHEAST THROUGH
THURSDAY...WHILE A SECONDARY WAVE OF PRECIPITATION MOVES IN ON
THURSDAY AHEAD OF THE UPPER TROUGH AXIS MOVES INTO THE UPPER
MISSISSIPPI VALLEY AND NEARS THE UPPER GREAT LAKES. THIS UPPER
TROUGH WILL SHIFT THE HEAVIEST PRECIPITATION OVER THE NORTHERN
HALF OF LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WITH THE
MOISTURE PRESENT AND FORCING FROM THE UPPER TROUGH...WOULD EXPECT
LINGERING LIGHT SHOWERS TO BE ONGOING OVER THE AREA FRIDAY INTO
FRIDAY NIGHT. PRECIPITATION TYPE IS VERY TRICKY AT THIS POINT DUE TO
THE VARYING SOLUTIONS IN THE MODELS WITH THE THERMAL FIELD WEDNESDAY
NIGHT INTO THURSDAY. AS THE INITIAL SURGE OF PRECIP MOVES INTO THE
AREA...IT ENCOUNTERS A ISOTHERMAL LAYER FROM THE SURFACE THROUGH
700MB WITH TEMPERATURES AT OR JUST ABOVE FREEZING. THIS LAYER
REMAINS STEADY THROUGH MUCH OF THURSDAY. AS FOR THE MODELS...THE
12Z GFS HAS TRENDED A LITTLE COOLER COMPARED TO THE PREVIOUS
RUNS...THE 12Z ECMWF REMAINS THE COOLEST AND THE 12Z GEM IS
IN BETWEEN INITIALLY. UNFORTUNATELY IT IS DIFFICULT TO GET TOO
SPECIFIC IN THESE SITUATIONS AS JUST A SLIGHT CHANGE IN TEMPERATURE
BETWEEN 925-700MB OF 1-2C ONE WAY OR ANOTHER CAN MAKE A HUGE
DIFFERENCE IN THE PRECIP TYPE AND ASSOCIATED IMPACTS. THUS...WILL
FOLLOW AN IDEA OF RAIN/SNOW MIX WITH THE INITIAL SURGE OF PRECIP AND
LIKELY TRANSITIONING TO MORE RAIN DURING THE DAY THURSDAY (OVER
THE SOUTH HALF). THE NORTHWARD EXTENT OF THIS TRANSITION IS
UNCERTAIN AT THIS POINT AND WILL PLACE IT OVER THE NORTH HALF OF
LAKE SUPERIOR THURSDAY AFTERNOON/EVENING. COLDER AIR WILL BEGIN TO
SHIFT INTO THE AREA ON THURSDAY NIGHT AS THE LOW SHIFTS EAST ACROSS
UPPER MICHIGAN AND LEAD TO A TRANSITION TO ALL SNOW INTO FRIDAY. BY
THE TIME THE PRECIPITATION WILL START TO TRANSITION TO ALL
SNOW...THE HEAVIEST RATES WILL HAVE DEPARTED THE AREA AND EXPECT
MORE OF A SCATTERED/LIGHT PRECIP TO REMAIN. WILL CONTINUE THE
PREVIOUS SHIFTS IDEA OF THE HIGHEST QPF OVER THE WESTERN HALF OF
THE CWA AND AROUND 0.5-1.0IN THROUGH THURSDAY EVENING. THAT MATCHES
UP WELL WITH SOME OF THE ECMWF/GFS QPF PROBS. AS MENTIONED
EARLIER...SNOW POTENTIAL IS TRICKY BUT THE SLIGHTLY COOLER
TREND SEEN IN THE 12Z MODELS CREATES CONCERN FOR MEASURABLE (AND
POTENTIALLY SIGNIFICANT) SNOWFALL OVER THE KEWEENAW DUE TO ITS
CLOSER PROXIMITY TO THE COLDER AIR TO THE NORTH. FINALLY FOR THIS
SYSTEM...THE COLD AIR AND BREEZING CONDITIONS SURGING IN BEHIND THE
LOW ON FRIDAY AND INTO SATURDAY WILL MAKE IT FEEL MORE LIKE MARCH
ACROSS THE AREA. WIND CHILL VALUES FRIDAY NIGHT AND INTO SATURDAY
WILL BE IN THE TEENS AND 20S WITH THE LOWEST VALUES NEAR LAKE
SUPERIOR.

MODELS DO DIFFER ON HOW QUICKLY THE UPPER TROUGH DEPARTS THIS
WEEKEND...SO THE FORECAST FOR THE END OF THE WEEKEND AND INTO EARLY
NEXT WEEK IS UNCERTAIN. EVEN WITH THIS UNCERTAINTY...THE GENERAL
IDEA OF BELOW NORMAL TEMPERATURES FOR THE WEEKEND AND INTO THE FIRST
PART OF NEXT WEEK SEEMS REASONABLE AS A HUDSON BAY HIGH BECOMES
STATIONARY AND LEADS TO DRY NORTHEASTERLY FLOW. PRECIPITATION
CHANCES WILL DEPEND ON THE NEXT UPPER TROUGH THAT LOOKS TO BE
LOCATED IN THE CENTRAL/SOUTHERN PLAINS AND AT THIS TIME MAY BE FAR
ENOUGH SOUTH TO KEEP THE AREA DRY.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 118 PM EDT MON APR 21 2014

DRY LOW-LEVEL AIR MASS WILL ALLOW VFR CONDITIONS TO CONTINUE THIS
AFTN AT KIWD/KCMX/KSAW. ALTHOUGH COLD FRONT HAS PASSED KIWD/KCMX AND
WILL REACH KSAW IN THE NEXT FEW HRS...DRY AIR MASS SHOULD PREVENT
ANY -SHRA FROM OCCURRING AT KSAW. TONIGHT...GUSTY NW WINDS THAT WILL
APPROACH 30KT AT THE MORE EXPOSED KCMX LOCATION WILL DRAW MUCH
COLDER AIR AS WELL AS LOW CLOUDS INTO THE UPPER LAKES. MVFR CIGS
WILL ARRIVE FIRST AT KCMX...EARLY THIS EVENING...AND THEN DURING THE
MID TO LATE EVENING AT KIWD/KSAW. CIGS WILL LIKELY FALL FURTHER TO
LOW MVFR AT KCMX/KSAW DURING THE NIGHT...AND IFR CIGS MAY EVENTUALLY
DEVELOP LATE. ARRIVAL OF DRIER AIR WILL RESULT IN CLOUDS CLEARING
OUT AT KIWD LATE TUE MORNING OR EARLY AFTN. CLEARING WILL OCCUR
LATER IN THE DAY AT KCMX/KSAW WITH KSAW THE LATEST.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 AM EDT MON APR 21 2014

LIGHT WINDS UNDER 15 KTS THIS MORNING ASSOCIATED WITH WEAK HIGH
PRESSURE RIDGE WILL SHIFT TO THE NW LATE TODAY/THIS EVENING
FOLLOWING A COLD FRONTAL PASSAGE AND INCREASE UP TO 25-30 KTS
TONIGHT AS MUCH COLDER AIR INVADES THE UPPER LAKES. NOT OUT OF THE
QUESTION THERE COULD BE SOME GALES OVER PORTIONS OF THE EAST HALF OF
THE LAKE UNDER THE SHARPER GRADIENT/STRONGEST LOW LEVEL WINDS.
MENTIONED SOME GALE FORCE GUSTS UP TO 35 KTS OVER THE ECENTRAL FOR
NOW. THESE STONG WINDS WILL DIMINISH TUE THRU WED AS A HI PRES RIDGE
AND WEAKER PRES GRADIENT MOVE OVER THE AREA. AS ANOTHER LOW PRESSURE
SYSTEM APPROACHES FROM THE PLAINS LATER IN THE WEEK AND THE GRADIENT
SHARPENS AGAIN...INCREASING SE WINDS WILL SHIFT TO THE NE. DEPENDING
ON THE TRACK AND INTENSITY OF THIS LO...THERE COULD BE AT LEAST A
PERIOD OF GALE FORCE WINDS.
&&

.HYDROLOGY...
ISSUED AT 409 PM EDT MON APR 21 2014

ANOTHER ABOVE NORMAL TEMPERATURE DAY WAS SEEN ACROSS UPPER MICHIGAN
TODAY...WITH HIGHS RISING INTO THE 50S TO LOWER 70S OVER MUCH OF
THE AREA. THESE WARM TEMPERATURES AND SUNSHINE HAS LIKELY LED TO
ANOTHER GOOD DAY OF MELTING IN THE AREAS THAT HAVE SNOW REMAINING.
STARTED TO SEE THE SECOND WAVE OF SNOW MELT RISES ON THE AREA
RIVERS YESTERDAY AND WILL CONTINUES TO SEE THAT INTO TONIGHT. BUT
COLDER TEMPERATURES EXPECTED TO ARRIVE ON TUESDAY SHOULD REALLY
SLOW THE MELT AND IN TURN LIMIT ADDITIONAL RISES. UNSETTLED WEATHER
WILL RETURN FROM THURSDAY THROUGH FRIDAY...ADDING TO THE RUNOFF. AT
THIS POINT THE BEST CHANCE OF SIGNIFICANT PRECIPITATION LOOKS TO BE
OVER THE WEST HALF OF UPPER MI...AND SPECIFICALLY THE KEWEENAW
PENINSULA...WHERE 0.50-1.00 INCH OF LIQUID WILL BE POSSIBLE BY
FRIDAY AFTERNOON. THERE IS SOME UNCERTAINTY ON HOW MUCH WILL FALL
AS RAIN AND HOW MUCH WILL FALL AS SNOW...BUT THE BEST CHANCE OF
SNOW WILL BE OVER THE KEWEENAW PENINSULA. WE WILL CONTINUE TO REFINE
THE FCST AS THE TIME NEARS.

SO FAR THE LOCATIONS EXPERIENCING SIGNIFICANT RISES HAVE BEEN
ALSTON/ALSM4/ ON THE STURGEON RIVER...ROCKLAND/RKLM4/ ON THE
ONTONAGON RIVER...CRYSTAL FALLS/CRYM4/ ON THE PAINT RIVER...AND TO A
LESSER EXTENT THE HYDE/FRDM4/ ON THE FORD RIVER (WHICH APPEARS TO
HAVE BEEN FROM AN ICE JAM).

WIDESPREAD FLOODING IS NOT FORESEEN AT THIS TIME...ALTHOUGH SOME
LOCATIONS MAY NEAR BANKFULL. HOWEVER...ANY RIVER THAT HAS ICE
REMAINING ON IT...ESPECIALLY THE ESCANABA RIVER IN DELTA
COUNTY...COULD EXPERIENCE AN ICE JAM WITH THE RISING RIVER
LEVELS THIS WEEK. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS
SHOULD MONITOR BOTH RIVER LEVELS AND ICE CONDITIONS. ICE JAMS CAN
FORM AND BREAK QUICKLY...RESULTING IN RAPIDLY FLUCTUATING RIVER
LEVELS.
&&

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

$$

SHORT TERM...KC
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...KC
HYDROLOGY...SRF






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