Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 222101
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
401 PM EST MON DEC 22 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 400 PM EST MON DEC 22 2014

UPPER MICHIGAN IS IN A LULL BETWEEN WAVES OF PRECIPITATION AT THIS
TIME...WITH THE NEXT PRECIPITATION PRODUCER TIED TO THE SURFACE LOW
THAT CURRENTLY STRETCHES FROM EASTERN SOUTH DAKOTA TO OMAHA
NEBRASKA. SOUTHEASTERLY FLOW AHEAD OF THIS LOW CONTINUES TO PULL
WARMER AIR INTO THE UPPER GREAT LAKES AREA...WITH 3PM TEMPERATURES
IN THE MID 30S UNDER MOSTLY CLOUDY SKIES AND FOG OVER THE WESTERN
AND CENTRAL U.P. OVER THE EAST...DRY LOW LEVEL AIR FROM LOWER
MICHIGAN HAS NOSED INTO THAT AREA AND STARTED TO SCATTERED THE
CLOUDS OUT. THAT DRIER AIR WILL TRY TO WORK ITS WAY WEST INTO THE
CENTRAL CWA AND BREAK UP SOME OF THE LOW CLOUDS AND FOG FOR THIS
EVENING.

AS THIS LOW DRIFTS SOUTHEAST THIS EVENING...A COUPLE SHORTWAVES
ROUNDING THE BASE OF THE UPPER TROUGH OVER THE NORTHERN/CENTRAL
PLAINS WILL INTENSIFY THE SOUTHERN EXTENT OF THE LOW OVER SOUTHERN
IOWA AND NORTHERN MISSOURI AROUND 06Z TONIGHT AND THEN LIFT THE LOW
TO THE NORTHEAST AND INTO EAST CENTRAL WISCONSIN BY 00Z WEDNESDAY.
AS THIS OCCURS...A SURFACE TROUGH WILL LIFT NORTH INTO UPPER
MICHIGAN DURING THE DAY. THERE WILL BE A COUPLE WAVES OF
PRECIPITATION IN THE SHORT TERM PERIOD. THE FIRST ONE WILL ARRIVE
LATE THIS EVENING AND INTO THE OVERNIGHT HOURS OVER THE SOUTHERN
U.P. AS MID LEVEL WARM AIR ADVECTION PUSHES NORTH INTO THE AREA AND
WEAKENS. THE SECOND AND STRONGER WAVE OF WARM AIR ADVECTION WILL BE
TIED TO THE SURFACE-700MB TROUGH AND MOVES INTO THE REGION ON
TUESDAY. MODELS SEEM TO BE CONVERGING ON THE SOLUTION OF THE
HEAVIEST BAND OF PRECIPITATION MOVING NORTH THROUGH THE AREA FROM
MID MORNING THROUGH THE LATE AFTERNOON HOURS. WHILE MUCH OF THE CWA
WILL SEE OVER 0.33 INCH OF LIQUID EQUIVALENT...EXPECT THE HEAVIEST
QPF TO BE OVER THE SOUTHEAST THIRD OF THE CWA AND ALSO OVER THE
NORTH CENTRAL WHERE THERE WILL BE SOME ADDED TERRAIN ENHANCEMENT
WITH THE EAST-NORTHEAST WINDS. 09Z SREF PROBABILITIES SUPPORT THE
IDEA OF THE HEAVIEST PRECIPITATION FALLING OVER THE CENTRAL/EASTERN
CWA.

LOOKING AT MODEL SOUNDINGS FOR THAT TIME FRAME...IT APPEARS THAT
MUCH OF THIS PRECIPITATION WILL FALL AS SNOW...EXCEPT FOR SOME
LOCATIONS RIGHT ALONG LAKE MICHIGAN AND MORE SPECIFICALLY OVER
SOUTHERN MENOMINEE COUNTY. IN THOSE AREAS...THERE APPEARS THAT THERE
WILL BE A POCKET OF WARMER AIR AROUND 950-875MB THAT WILL WARM THE
LOW LEVEL TEMPS UP TO 3C AND ELIMINATE MOST IF NOT ALL SNOW
POTENTIAL. BUT AS YOU TRAVEL NORTH-NORTHEAST ALONG THE LAKE MICHIGAN
SHORELINE...THAT AMOUNT OF WARM AIR REALLY BEGINS TO
WEAKEN...ESPECIALLY AS THE MAIN AREA OF PRECIPITATION WRAPS UP. MANY
OF THOSE AREAS OVER THE SOUTH CENTRAL AND SOUTHEAST HAVE THEIR
WETBULB TEMPERATURES WITHIN THE VERTICAL PROFILE STRUGGLING TO RISE
ABOVE 0C...WHICH WOULD INDICATE AS THAT MODERATE PRECIPITATION
BEGINS TO FALL IT WOULD COOL TOWARDS THAT. THUS...WILL TREND THE
FORECAST TO MAINLY SNOW OVER THE REST OF THE SOUTHEAST AND EASTERN
PART OF THE CWA AS THAT HEAVIEST PRECIPITATION ROTATES NORTH THROUGH
THE AREA DURING THE DAY TOMORROW. BUT AS THE HEAVY SNOW SHIFTS
NORTH-NORTHWEST IN THE AFTERNOON...THE WARMER AIR WILL SPREAD INTO
THE SOUTHEAST U.P. ALONG/BEHIND THE INVERTED TROUGH WHILE A DRY
SLOT MOVES IN ALOFT. THINK THIS WARM AIR WILL ARRIVE AFTER THE
HEAVIEST PRECIPITATION (LIMIT POTENTIAL FOR THAT PRECIP TO CHANGE
TO RAIN)...BUT IT WILL TRANSITION ANY LINGERING PRECIPITATION TO A
LIGHT RAIN OR DRIZZLE AS ICE CRYSTALS ARE REMOVED FROM THE CLOUDS.
SINCE MOST OF THE FORCING AND CLOUD WILL BE BELOW THE DGZ...EXPECT
SNOW RATIOS TO BE AROUND THE 10 TO 1 RANGE FOR MUCH OF THE PERIOD
AND WILL FOLLOW THAT FOR THE FORECAST. WITH THAT PRECIPITATION TYPE
EXPECTATION AND LOCATION OF THE HEAVIEST QPF...HAVE SNOWFALL AMOUNTS
IN THE ADVISORY RANGE FOR MUCH OF THE CWA. THINK SOME OF THE AREAS
OUT WEST (AND ALSO WHERE IT MIXES WITH RAIN) WILL BE ON THE LOW END
OF OUR ADVISORY CRITERIA (3IN PER 12HRS)...BUT OTHERWISE HAVE
SNOWFALL AMOUNTS OF 3 TO 5 INCHES IN MOST LOCATIONS FOR LATE
TONIGHT THROUGH TUESDAY. WITH RATES AROUND ONE INCH AN HOUR OVER THE
CENTRAL/EASTERN CWA (DURING THE LATE MORNING THROUGH MID AFTERNOON
TIME PERIOD) THINK THE ACCUMULATION WILL BE FAST ENOUGH TO MAKE FOR
HAZARDOUS TRAVEL IN THOSE AREAS DURING THE EARLY EVENING COMMUTE.
WINTER WEATHER ADVISORY HAS ALREADY BEEN ISSUED FOR OVERNIGHT
TONIGHT THROUGH TUESDAY...WITH A FOCUS ON THE SNOW FOR TUESDAY.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 438 AM EST MON DEC 22 2014

...WIDESPREAD MODERATE SNOW ON TUESDAY...

ONE PRIMARY CHANCE FOR ACCUMULATING SNOW OVER ALL OF CWA IN THE LONG
TERM ON TUESDAY BUT CANNOT RULE OUT MORE SNOW CHIRSTMAS EVE FOR
EASTERN CWA AS THE ON AGAIN OFF AGAIN LOW PRESSURE SYSTEM IS STILL
AROUND IN LATEST MODELS. ANOTHER SYSTEM MAY IMPACT REGION WITH SWATH
OF SNOW FRIDAY INTO SATURDAY...BUT LACK OF CONTINUITY FM THE MODELS
LIMITS CONFIDENCE IN THAT PART OF FORECAST ATTM.

EVOLVING LOW PRESSURE SYSTEM MOVING OUT OF THE PLAINS TUESDAY INTO
WEDNESDAY APPEARS MORE LIKE RECENT RUNS OF ECMWF. QUESTION IS HOW
FAR EAST THE MID-LEVEL AND SFC LOWS REACH ON TUESDAY AS THAT IMPACTS
DRY SLOT AND PRECIP INTENSITY...ESPECIALLY OVER THE SOUTHERN PART OF
CWA. BLEND OF NAM/SREF SUPPORTED BY NCEP AND LOOKED LIKE 12Z ECMWF.
PRIMARY SHORTWAVE AND SFC LOW MOVE TO EASTERN IOWA BY 12Z TUESDAY
AND LIFT ACROSS EASTERN WISCONSIN ON TUESDAY AFTN. CIRCULATION AROUND
SFC-H85 LOWS PULLS H7 MIXING RATIOS OVER 3G/KG NORTH OF THE LOWS OVER
MAJORITY OF UPR MICHIGAN. PER GARCIA METHOD WITH NO PTYPE
CONSIDERATIONS THAT WOULD FAVOR 3 INCHES OF SNOW IN 6 HRS. BLEND OF
FAVORED QPFS POINT TO 0.30-0.50 INCH OF LIQUID EQUIVALENT OVER MOST
CWA...WITH HIGHER AMOUNTS OVER 0.50 INCH OVER FAR WEST AND SCNTRL.
TROUBLE IS 00Z ECMWF TRENDED EAST WITH SFC LOW AND HAS DRY SLOT INTO
SCNTRL...REALLY CUTTING ITS PRECIP THERE.

PTYPE ALSO AN ISSUE...UNFORTUNATELY. SOUNDINGS FM NAM KEEP BLYR
COOL...WITH ONLY SURE CHANGE TO RAIN AT MNM WITH ENE FLOW OFF BAY OF
GREEN BAY. ENE WINDS WOULD LEAD TO COOLING TO PERSIST AT KESC AND
KISQ. GFS SIMILAR WHILE GEM-REGIONAL IS MUCH WARMER/WESTWARD WITH
1000-850MB THICKNESSES OVER 1305M. SINCE WINDS ARE BACKING AND OFF
LAND IN LOW-LAYERS WILL FAVOR COOLER IDEA OFFERED BY NAM/GFS IN THE
MORNING BUT WILL BRING MORE GEM IDEA IN THE AFTN AS SFC LOW EDGES
CLOSER TO THE AREA FM THE SOUTH. RESULT WILL BE RAIN/SNOW MIX OVER
SCNTRL UPR MICHIGAN ALONG BAY OF GREEN BAY...WITH SNOW ELSEWHERE
INTO EARLY AFTN...THEN GO FOR A MIX OF RAIN AND SNOW OVER MOST OF
THE EAST HALF CWA BY MID AFTN. NAM SOUNDINGS SHOW THE SNOW MAY LAST
THROUGH THE DAY OVER MOST OF THE WEST HALF OF CWA AND EVEN FOLLOWING
GEM THICKNESSES QPF THAT OCCURS THERE IN THE MORNING WOULD STAY ALL
SNOW. OVERALL...WILL LEAN TOWARD MOST SNOW OVER WEST HALF. SOUNDINGS
MAINTAIN LOOK OF ELEVATED NARROW DGZ AND TEMPS WARMER THAN -8C
BLO...SO LOW SLR/S...PROBABLY AROUND 10:1. BY LATE TUESDAY
AFTN...EXPECT TOTAL SNOWFALL OVER 4 INCHES OVER MOST OF THE WEST
HALF OF THE CWA...MAYBE PUSHING TOWARD 6 INCHES OVER INTERIOR WEST.
CLOSER TO LK SUPERIOR OVR NCNTRL WHERE ENE WINDS PROVIDE FLOW OF
LAKE MODIFIED WARMING...EXPECT SNOW TOTALS TO BE HELD DOWN. CONTINUED
TO INCREASE POPS TO CATEGORICAL. IT WILL SNOW. ONLY THING THAT
TEMPERS CONFIDENCE ON ISSUING 3RD PERIOD ADVY IS INCONSISTENCIES IN
WHERE THE HIGHER QPF IS ON MODELS. WILL OPT FOR A SPECIAL WEATHER
STATEMENT AND LET DAYSHIFT GET SOME MORE DATA BEFORE MAKING FINAL
CALL ON HEADLINE.

BULK OF PRECIP WILL BE DONE BY WEDNESDAY EVENING. 00Z NAM WAS QUITE
EMPHATIC WITH DEFORMATION ZONE OF LINGERING SNOW OVER THE WEST CWA
BUT WAS NOT SUPPORTED IN ITS INTENSITY BY ANY OTHER GUIDANCE. 06Z
NAM IS NOT AS BULLISH. THOUGH SOME LGT SNOW COULD CONTINUE AS AN
AREA OF MID LEVEL FGEN/DEFORMATION WILL BE REINFORCED BY WEAK TROWAL.
EVEN THIS AREA OF SNOW SHOULD DIMINISH TO LGT SNOW/FLURRIES LATE ON
TUESDAY NIGHT. FARTHER EAST...SOUNDINGS SIGNAL POSSIBLE DRIZZLE OR
FREEZING DRIZZLE AND FOG AS MID-LEVEL DRYING LEAVES MOIST LOW-LEVELS
WITH TEMPS MAINLY WARMER THAN -7C. CARRIED SLIGHT CHANCE POPS FOR
RAIN/SNOW...BUT THIS MAY NEED TO BE CONVERTED TO DZ/FOG WITH LATER
FORECASTS.

MODELS CONTINUE TO HAVE FUN WITH THE CHRISTMAS EVE SYSTEM AFFECTING
THE GREAT LAKES. AFTER BACKING AWAY COMPLETELY 24 HR AGO...MOST OF
THE MODELS CAME BACK TO SHOWING A STRONG LOW LIFTING NORTHWARD OVER
THE CNTRL GREAT LAKES WITH THE RUNS ON SUNDAY. THAT IS WHERE WE
REMAIN FOR MOST PART NOW...WITH ALL BUT THE GEM-GLOBAL AND PARALLEL
GFS INDICATING THIS SYSTEM MISSES UPR MICHIGAN. KEPT SMALL CHANCES
IN OVER FAR EAST...VCNTY OF LUCE COUNTY...BUT OTHERWISE KEPT THE CWA
VOID OF ANY POPS FM THE SYSTEM. HAVE SOME SMALL CHANCE POPS OVER THE
WEST HALF ON CHRISTMAS EVE DAY...BUT THIS IS GENERALLY DUE TO SOME
SIMBLANCE OF THE LINGERING DEFORMATION AREA FM THE TUESDAY SYSTEM
THAT WILL ONLY BE SLOWLY UNRAVELING OVER THE EAST PART OF CWA ON
WEDNESDAY.

INTO CHRISTMAS AND BEYOND...RAN WITH CONSENSUS. COULD SEE SOME LGT
LK EFFECT FOR WNW-NW FLOW AREAS ON CHRISTMAS THOUGH H85 TEMPS NEAR
-10C ARE ONLY MARGINAL FOR PURE LES. WOULD NEED SOME ADDITIONAL
LARGE SCALE SUPPORT TO RESULT IN BETTER CHANCES OF LES VIA LAKE
ENHANCEMENT. AS LONG AS THE CNTRL GREAT LAKES LOW DOES NOT COME ANY
FARTHER WEST...WILL NOT BE VERY WINDY EITHER. HIGHS ON CHRISTMAS TOP
OUT ABOVE NORMAL...WITH LOW TO MID 30S EXPECTED. AS ALLUDED TO
EARLIER...ANOTHER CLIPPER TYPE SYSTEM COULD SPREAD SOME LGT SNOW TO
THE AREA ON FRIDAY. UNCERTAINTY AND CONSISTENCY IN THAT IDEA BOTH
ARE HIGH...SO CHANCE POPS UNTIL IT GETS MORE REFINED. AT THE MOST
COULD SEE MODERATE SNOW AMOUNTS. IDEA OF COLDER WEATHER WITH LK
EFFECT STILL ON TRACK FOR THE WEEKEND. MOISTURE IS A QUESTION THOUGH
SO EVEN THOUGH H85 TEMPS FALL DOWN BLO -15C ON SUNDAY...EVEN
MODERATE LK EFFECT SNOW IS NOT A DONE DEAL YET. COOLER TEMPS WILL BE
NOTICABLE THOUGH AFTER THE RATHER MILD CHRISTMAS WEEK.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1257 PM EST MON DEC 22 2014

MVFR TO IFR CEILINGS COVER MUCH OF UPPER MICHIGAN AS MOIST
SOUTHEASTERLY FLOW IS OCCURRING AHEAD OF A LOW PRESSURE SYSTEM IN
EASTERN SOUTH DAKOTA. AT KSAW...CEILINGS AND VISIBILITES ARE LOWER
DUE TO THE FAVORABLE UPSLOPE WIND DIRECTION. EXPECT THESE LOWER
CLOUDS TO REMAIN INTO THE EVENING HOURS...ALTHOUGH THEY MAY RAISE
SOME TOWARDS LATE AFTERNOON AS DRIER AIR FROM LOWER MICHIGAN
ATTEMPTS TO WORK INTO THE AREA. HAD THE GREATEST CONFIDENCE AT
CONDITIONS STAYING AT OR BELOW MVFR...BUT THERE COULD BE A PERIOD OF
VFR CEILINGS IF THE DRIER AIR CAN WORK INTO THE AREA.

SNOW WILL WORK INTO THE AREA OVERNIGHT INTO TUESDAY AS THE LOW
PRESSURE SYSTEM LIFTS 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 STRONGEST SNOW
AND DID DROP KSAW DOWN TO LIFR VISIBILITES TO ACCOUNT FOR THAT
MOVING THROUGH LATE IN THE TAF PERIOD.
&&

.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 FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST
     /6 PM CST/ TUESDAY FOR MIZ001>007-009>011-084-085.

  WINTER WEATHER ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING
     TO 4 PM EST /3 PM CST/ TUESDAY FOR MIZ012>014.

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

$$

SHORT TERM...SRF
LONG TERM...JLA
AVIATION...SRF
MARINE...SRF





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