Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 230926
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
426 AM EST TUE DEC 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST TUE DEC 23 2014

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.

TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.

TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. MIN
TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO LOWER THAN THE UPR
20S OVER THE INTERIOR W. MAINTAINED MENTION OF FOG THRU THE NGT OVER
THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN ABOVE 32 WITH MOIST AIR
OVER MELTING SN.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 511 PM EST MON DEC 22 2014

HIGHS WILL REMAIN IN THE 30S THROUGH THE DAY FRIDAY...WITH PLENTY OF
GOING ON PRECIP WISE THIS PERIOD. SLUSHY TO WET ROADWAYS WILL GREET
HOLIDAY TRAVELERS THROUGH FRIDAY...UNLESS A QUICK BURST OF SNOW
OCCURS.

INITIALLY HAVE THE EXITING SFC LOW SHIFTING FROM WI AT 00Z
WEDNESDAY...SHIFTING ACROSS LAKE MI OVERNIGHT INTO
WEDNESDAY...BECOMING A PART OF THE NEXT LOW NEARING FROM THE TN
VALLEY WEDNESDAY MORNING. DRIZZLE/FREEZING DRIZZLE WILL LINGER
THROUGH WEDNESDAY OVER THE E THIRD OF THE CWA...BEFORE CHANGING TO
SNOW LATE IN THE DAY.

ALTHOUGH THERE ARE STILL SOME DISCREPANCIES IN EVEN THE WEDNESDAY
NIGHT FCST...I DID TAKE OUT THE MENTION OF THE LOW PUSHING NORTHWARD
OVER E LOWER MI AND LAKE HURON LATE WEDNESDAY INTO WEDNESDAY EVENING
FOR THE EAST HALF OF UPPER MICHIGAN IN THE HWO. THE 22/00Z ECMWF IS
STRONGER/MORE WRAPPED UP...AND AS A RESULT KEEPS WRAP AROUND PRECIP
WEDNESDAY NIGHT INTO THURSDAY OVER OR JUST E OF THE CWA. THE 22/12Z
RUN WAS SLOWER...AND STILL KEPT MUCH OF THE PRECIP AROUND LUCE
COUNTY AND E. THE 18Z GFS WENT BACK TO A SLIGHTLY MORE W IDEA WITH
THE PRECIP. STILL LOOKS LIKE THE COUNTIES ALONG LAKE MI...AND LUCE
COUNTY WILL BE THE MAIN IMPACTS...WITH SOME LAKE ENHANCEMENT OVER N
CENTRAL UPPER MI. IF THE 18Z GFS PANS OUT...MORE SIGNIFICANT CHANGES
BACK TO OUR PREVIOUS FCST/HWO DISCUSSION WILL BE NEEDED. THE 12Z
RUNS HOWEVER WERE MORE CONSISTENT ON KEEPING THE WIDESPREAD PRECIP E.

LOW PRESSURE TRACKING NORTHEASTWARD FROM THE CENTRAL PLAINS THURSDAY
NIGHT THROUGH THE UPPER GREAT LAKES LATE FRIDAY AFTERNOON AND FRIDAY
NIGHT WILL BRING THE POTENTIAL FOR WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO ALL OF UPPER MICHIGAN. THERE IS STILL PLENTY OF
DISCREPANCY...WITH THE 22/12Z ECMWF KEEPING MUCH OF THE PRECIP OVER
THE W THIRD TO HALF OF THE CWA. THE GFS IS A BIT MORE
GENEROUS...WITH A HEALTHY SWATH OF 0.1IN LIQUID. ADDED THE LIGHT TO
MODERATE SNOW POTENTIAL TO THE HWO FOR HOLIDAY TRAVELERS. RAIN MAY
MIX IN OVER LAKE MI FRIDAY AFTERNOON...BEFORE MUCH COOLER AIR PUSHES
IN ACROSS THE ENTIRE AREA FRIDAY NIGHT. 850MB TEMPS W AT 12Z
SATURDAY COULD BE AROUND -16C ON A FAVORABLE NW WIND...EXTENDING
SNOW OVER THE W INTO SUNDAY.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014

DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING NORTHEAST TOWARDS THE
AREA. THERE WILL LIKELY BE TWO SURGES OF PRECIPITATION WITH THIS
LOW...THE FIRST COMING DURING THE OVERNIGHT HOURS AND THE SECOND
ARRIVING BY LATE MORNING OR EARLY AFTERNOON. THE SECOND WAVE WILL
PRODUCE THE HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON DEC 22 2014

A LOW PRESSURE SYSTEM OVER THE MISSOURI RIVER VALLEY WILL LIFT
NORTHEAST ON TUESDAY THROUGH EASTERN UPPER MICHIGAN WHILE
WEAKENING. WINDS WILL TURN TO THE EAST-NORTHEAST TONIGHT AND
CONTINUE THROUGH TUESDAY. WHILE MOST LOCATIONS WILL SEE WINDS IN
THE 20-30KT RANGE...THERE MAY BE A FEW GALE FORCE GUSTS TO 35KTS
OVER WESTERN LAKE SUPERIOR. AS THE LOW CONTINUES TO WEAKEN ON
TUESDAY NIGHT...ANOTHER LOW WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY. THIS LOW WILL QUICKLY LIFT NORTHEAST ON
WEDNESDAY...CROSSING LAKE HURON ON WEDNESDAY NIGHT AND MOVING INTO
NORTHERN QUEBEC ON THURSDAY. AT THIS TIME...EXPECT NORTHERLY WINDS
TO STAY BELOW 25KTS OVER LAKE SUPERIOR DURING THAT PERIOD. ANOTHER
LOW WILL TAKE SHAPE IN THE CENTRAL PLAINS ON THURSDAY NIGHT AND
THEN MOVE NORTHEAST THROUGH THE UPPER GREAT LAKES REGION ON FRIDAY
NIGHT. NORTHEAST WINDS UP TO 30 KNOTS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY BEHIND THIS LOW.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
     FOR MIZ001>007-009>011-084-085.

  WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
     FOR MIZ012>014.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...SRF



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