Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 212111
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
411 PM EST FRI NOV 21 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 406 PM EST FRI NOV 21 2014

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL MID/UPPER LEVEL FLOW
THROUGH THE NW AND N CNTRL CONUS WITH A WEAK SHORTWAVE TROUGH OVER
NORTH DAKOTA. A VIGOROUS SRN STREAM SHRTWV WAS SLIDING THROUGH SW
ARIZONA. AT THE SFC...SW FLOW WAS INCREASING FROM THE UPPER MS VALLEY
INTO THE NRN LAKES AS THE PRES GRADIENT TIGHTENS BETWEEN A 995 MB LOW
OVER MANITOBA AND 1034 MB HIGH OVER THE OH VALLEY. WAA INTO THE
REGION HAS BROUGHT AN INCREASE IN MID CLOUDS ACROSS UPPER MI WITH
ANOTHER BATCH UPSTREAM FROM MN INTO CNTRL WI. THE LOWER CLOUDS
REMAINED WELL TO THE SOUTH OVER MO AND SRN IA.

TONIGHT...EXPECT THAT THE STRONG SSW LOW LEVEL WAA PATTERN WILL
RAPIDLY BRING LOW LEVEL MOISTURE TOWARD THE AREA TO SUPPORT LOWER
CLOUDS INTO THE CWA. ALTHOUGH THE LOW LEVEL ISENTROPIC LIFT WILL BE
MARGINAL TO PRODUCE PCPN...UPSLOPE FLOW INTO MUCH OF THE AREA SHOULD
BE ENOUGH TO SUPPORT SOME LIGHT PCPN...ESPECIALLY OVER THE EAST HALF
WHERE ADDITIONAL MOISTURE FROM LAKE MICHIGAN IS AVAILABLE. MODEL
SOUNDINGS SUGGEST THAT THE 3K-8K DRY/WARM LAYER WILL BE STRONG ENOUGH
TO LIMIT/PREVENT ICE CRYSTAL AVAILABILITY INTO THE LOWER MOIST LAYER.
SO...EXPECT -FZDZ WILL BE THE PREDOMINANT PCPN TYPE. EVEN THOUGH
LITTLE IF ANY MEASURABLE PCPN IS EXPECTED...EVEN A VERY THIN COATING
OF -FZDZ COULD RESULT IN HAZARDOUS CONDITIONS ON UNTREATED ROADS.

SAT...THE COMBINATION OF DAYTIME HEATING AND ADDITIONAL WAA WILL
PUSH TEMPS ABOVE FREEZING IN MOST AREAS BY NOON CHANGING ANY
LINGERING FREEZING DRIZZLE TO DRIZZLE. EXPECT THE PCPN CHANCES TO
DIMINISH AS THE LOW LEVEL WAA WEAKENS DURING THE LATE MORNING AND
AFTERNOON. OTHERWISE...TEMPS SHOULD CLIMB TO READINGS AT OR ABOVE
NORMAL IN THE MID TO UPPER 30S.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 526 AM EST FRI NOV 21 2014

BIG CHANGES ARE STILL EXPECTED DURING THE LONG TERM PORTION OF THE
FCST. THE HIGHLY AMPLIFIED PATTERN THAT HAS BROUGHT PERSISTENTLY
MUCH BLO NORMAL TEMPS INTO THE UPPER GREAT LAKES WILL RELAX
SIGNIFICANTLY OVER THE NEXT COUPLE OF DAYS AS A STRONG WAVE PLOWS
INTO THE PAC NW FORCING THE TROUGH OUT FM ERN NORTH AMERICA. THIS
CHANGE OCCURS QUICKLY AS MODELS SHOW 220-240M 500MB HEIGHT RISES
OVER UPPER MI THIS MORNING AHEAD OF BUILDING RIDGE FM THE PLAINS.
SO...AFTER AN UNSEASONABLY LONG STRETCH OF COLD WEATHER FOR NOV
(RECORD BREAKING SUBFREEZING STREAK AT NWS MQT FOR NOV AND ALSO 6
CONSECUTIVE DAYS OF RECORD LOW MAX TEMPS)...EXPECT A QUICK
TRANSITION BACK TO NORMAL/ABOVE NORMAL TEMPS THIS WEEKEND. THE
STRONG PACIFIC SHORTWAVE SURGING INTO THE WRN CONUS WILL CARVE OUT A
SIGNIFICANT SRN STREAM TROF THIS WEEKEND LEADING TO THE DEVELOPMENT
OF A RAPIDLY DEEPENING SFC LOW LIFTING FROM NORTH TX SUN MORNING TO
NEAR THE MACKINAC STRAITS BY MONDAY WITH PRES BOTTOMING OUT IN THE
HIGH 970S MB OVER THE UPPER LAKES. WITH SIGNIFICANT WARMING
ANTICIPATED AHEAD OF THE DEEPENING SFC LOW...RAIN WILL OCCUR ON
SUNDAY AHEAD OF THE STORM SYSTEM WITH MODERATE PCPN AMOUNTS POSSIBLE
OVER THE CENTRAL AND ERN CWA. AS COLDER AIR WRAPS INTO THE AREA ON
THE BACKSIDE...THERE WILL BE A TRANSITION BACK TO SNOW ON MON WITH
THE POTENTIAL FOR MODERATE TO HEAVY SNOW ACCUMULATIONS INTO
TUE...MAINLY NEAR LAKE SUPERIOR. AFTER THIS WEEKENDS WARMUP...MODELS
POINT TOWARD A COLD PATTERN BECOMING RE-ESTABLISHED NEXT WEEK AS
HEIGHTS RISE AGAIN OVER WRN NORTH AMERICA/NE PACIFIC. THIS WILL
ALLOW FOR ARCTIC AIR TO SPILL S TOWARD THE CENTRAL CONUS/GREAT LAKES
REGION AGAIN. MANY OF THE MODELS CONTINUE TO INDICATE THE COLDEST
AIR OF THE SEASON (WELL BLO -20C 8H TEMPS) DROPPING SE INTO THE
UPPER GREAT LAKES TOWARD THE END OF NEXT WEEK. WHETHER THIS COLD
PATTERN WILL AGAIN BECOME PERSISTENT LIKE WHAT WE`VE SEEN THIS PAST
WEEK REMAINS TO BE SEEN...BUT THERE IS RECENT SUPPORT FROM THE NAEFS
AND CFSV2 RUNS THAT COLDER THAN NORMAL CONDITIONS COULD PERSIST INTO
EARLY DECEMBER.

BEGINNING SAT...WITH INCREASING ISENTROPIC ASCENT IN STRENGTHENING
WSW FLOW BETWEEN HIGH PRES MOVING OFF THE E COAST AND LOW PRES
MOVING ACROSS SCNTRL CANADA...SOME OF THE MODELS GENERATE SOME VERY
LIGHT PCPN OVER THE ERN FCST AREA ON SAT WHERE ISENTROPIC ASCENT IS
MAXIMIZED. HOWEVER...PERSISTENCE OF DRIER AIR IN THE 850-700MB LAYER
AS NOTED ON THE 00Z GFS/NAM BUFR SOUNDINGS WARRANTS NOTHING MORE
THAN SCHC POPS TO LOW CHC POPS SAT. GIVEN DRYNESS NOTED IN MID-LVLS
AND THE SFC BASED MOIST LAYER WARMER THAN -10C...PCPN MAY END UP
MOSTLY AS -DZ/-FZDZ IF ANY PCPN DOES OCCUR. EXPECT TEMPS ON SAT TO
RISE ABOVE FREEZING EVERYWHERE.

SAT NIGHT...WEAK HEIGHT RISES AND FAIRLY DRY AIRMASS SUGGEST MOSTLY
DRY CONDITIONS. WITH LIGHTER WINDS UNDER DRIER MID LEVELS...EXPECT
MIN TEMPS TO FALL INTO THE 20S TO AROUND 30F IN GENERAL.

SUN INTO MON...MODELS CONTINUE TO INDICATE LOW PRES DEVELOPING OVER
THE SRN PLAINS SAT NIGHT/SUN MORNING IN RESPONSE TO THE STRONG
PACIFIC SHORTWAVE DIGGING INTO THE BASE OF THE SRN STREAM TROUGH.
MEANWHILE...ADDITIONAL ENERGY MOVING OUT OVER THE NRN PLAINS WILL
HELP PULL THIS SYSTEM NORTH AND WITH THE SUBSEQUENT PHASING THE SFC
LOW IS EXPECTED TO DEEPEN INTO THE 970S MB BY THE TIME IT REACHES
THE UPPER LAKES MON MORNING. THE GFS HAS BEEN REMARKABLY CONSISTENT
FOR SEVERAL RUNS NOW SHOWING AROUND 980 MB SFC LOW TRACKING TO NEAR
MACKINAC STRAITS BY 12Z MON. THE 12Z ECMWF RUN HAD TRENDED FARTHER
EAST TOWARD THE GFS SOLN TRACK AND THE LATEST 00Z RUN SHOWS A
SIMILAR TRACK AND A BIT QUICKER SOLN SIMILAR TO THE 00Z GFS RUN. THE
GEM-NH HAS ALSO SHOWN A SIMILAR TRACK TO THE GFS BUT AGAIN WAS
SOMEWHAT SLOWER LIKE THE ECMWF BUT NOT QUITE AS DEEP. ALL MODELS
SUGGEST THAT PCPN ON THE FRONT SIDE OF THIS SYSTEM WILL BE ALL RAIN
FOR UPPER MI ON SUNDAY. HOWEVER...NOT OUT OF THE QUESTION THAT THERE
COULD BE A LITTLE -FZRA AT THE ONSET SUNDAY MORNING IF TEMPS ARE
STILL CLOSE TO FREEZING WHEN PCPN BEGINS. OTHERWISE...MODELS FAIRLY
CONSISTENT SHOWING BEST SURGE OF RAIN INTO UPPER MI LATE SUN
MORNING/AFTN AND CONTINUING SUN NIGHT. EXPECT AT LEAST MODERATE PCPN
RANGING FROM .25 FAR WEST TO AROUND AN INCH EAST AND SOUTH CENTRAL
WHERE MOISTURE TRANSPORT WILL BE STRONGER/MORE SUSTAINED NEAR TRACK
OF SFC LOW.

AS THE SYSTEM LIFTS NNE AND THE COLUMN COOLS UNDER FALLING
HEIGHTS...MODELS INDICATE DEFORMATION/COMMA HEAD PCPN SHIELD
DEVELOPING. THE FCST CHALLENGE WILL BE DETERMINING THE STRENGTH AND
PERSISTENCE OF THIS DEFORMATION PCPN SHIELD AND WHERE IT WILL SET
UP. 00Z MODELS STILL SHOW PLENTY OF DIFFERENCES IN THIS REGARD WHICH
WILL BE CRITICALLY IMPORTANT IN DETERMINING POTENTIAL FOR MODERATE
TO HEAVY SNOW BEHIND THE SYSTEM. THE 00Z ECMWF SHOWS A BETTER
DEFINED DEFORMATION PCPN SHIELD THAN EITHER THE GFS OR GEM-NH. WITH
850MB TEMPS COOLING TO AROUND -12C BY 00Z TUE...LAKE ENHANCEMENT
WILL ALSO COME INTO PLAY. SO AFTER THE RAIN ON SUN/SUN NIGHT...STILL
BELIEVE THERE WILL BE A POTENTIAL FOR MODERATE TO POTENTIALLY HEAVY
SNOW OVER WRN UPPER MI MON AFTN INTO MON NIGHT ALONG WITH BLUSTERY
NW WINDS AND WILL CONTINUE TO HIGHLIGHT IN HWO AND EHWO GRIDS. THE
SNOW/WIND WILL SPREAD INTO THE ERN FCST AREA AS WELL...BUT WITH
DEFORMATION PCPN TENDING TO LIFT NE...SNOWFALL WILL LIKELY BE
LIGHTER THAN OVER THE W.

WITH 850MB TEMPS AROUND -14C TUE...NW FLOW LAKE ENHANCEMENT WILL
TRANSITION TO PURE LES AS TROF SHIFTS E AND DEEP MOISTURE DEPARTS.
WITH A TREND TOWARD MORE ANTICYCLONIC FLOW...THERE WILL BE A
DIMINISHING OF LES THRU THE DAY NEAR THE LAKE.

HEADING INTO WED/THU...SOME OF THE MODELS...PARTICULARLY THE
ECMWF...SHOW INDICATIONS OF A CLIPPER TYPE SHORTWAVE BRINGING A
POTENTIAL PERIOD OF -SN...FOLLOWED BY A SURGE OF COLDER AIR AND
RENEWED LES HEADING INTO THANKSGIVING. HOWEVER...GIVEN THAT THERE
IS STILL INCONSISTENCY WITH THE MODELS REGARDING TIMING/TRACK OF
CLIPPER SYSTEM WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH WHICH
KEEPS POPS HIGHEST NEAR LAKE SUPERIOR.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 246 PM EST FRI NOV 21 2014

MID CLOUDS WITH GUSTY SSW WINDS PREVAILED THIS AFTRNOON AS WARM
ADVECTION TAKES OVER BETWEEN LOW PRESSURE OVER THE PLAINS AND HIGH
PRES OVER THE OH VALLEY. LLWS IS EXPECTED AS THE LOW LEVEL JET
REALLY INCREASES 1-2KFT ABOVE THE SURFACE...ESPECIALLY AT KSAW. HAVE
LEFT GUSTS UP TO ACCOUNT FOR THIS. MVFR CLOUDS WILL BE PUSHING
NORTH-NORTHEAST INTO THE AREA TONIGHT. THIS WILL LEAD TO A QUICK
DROP IN CEILINGS LATE TONIGHT...WITH KSAW HAVING THE LOWEST VALUES
THAT SHOULD FALL INTO THE IFR RANGE LATE. WITH THESE LOW
CLOUDS...THERE IS THE POTENTIAL FOR LIGHT FREEZING DRIZZLE LATE
TONIGHT...ESPECIALLY AT KSAW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 PM EST FRI NOV 21 2014
WINDS WILL CONTINUE TO INCREASE WITH A TIGHT PRES GRADIENT BETWEEN
LOW PRES OVER THE PLAINS AND A RIDGE OVER THE OH VALLEY.
WINDS TOT 30KTS WITH FREQUENT GALE FORCE GUSTS TO 35 KNOTS ARE
EXPECTED TONIGHT. THE PRESSURE GRADIENT WILL DECREASE SATURDAY INTO
SATURDAY NIGHT AS A TROUGH TRAILING THE CANADIAN LOW DROPS SOUTHEAST
OVER LAKE SUPERIOR. A DEVELOPING LOW IN THE CENTRAL/SOUTHERN PLAINS
ON SATURDAY NIGHT WILL LIFT NORTHEAST THROUGH THE GREAT LAKES REGION
TO NEAR THE STRAITS MONDAY MORNING AT AROUND 28.9 INCHES. AS THE LOW
LIFTS TO THE NORTHEAST ON MONDAY NORTHERLY GALES ARE LIKELY WHICH
COULD PERSIST THROUGH MONDAY NIGHT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WARNING UNTIL 7 AM EST SATURDAY FOR LSZ266-267.

  GALE WARNING UNTIL 7 AM EST /6 AM CST/ SATURDAY FOR LSZ162-263-
     264.

LAKE MICHIGAN...
  GALE WARNING UNTIL 10 AM EST SATURDAY FOR LMZ248.

&&

$$

SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...JLB
MARINE...JLB






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