Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 232024
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
424 PM EDT SAT APR 23 2016

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 424 PM EDT SAT APR 23 2016

WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW SPLIT FLOW OVER NAMERICA.
IN THE NRN STREAM...A TROF EXTENDS THRU HUDSON BAY INTO SE CANADA
BTWN RIDGING OVER WRN CANADA AND A CLOSED MID LEVEL HIGH CENTERED
JUST SE OF GREENLAND. IN THE SRN STREAM...A TROF IS OVER THE WRN
CONUS WITH RIDGING OUT OVER THE PLAINS. JET STREAK DEVELOPING IN THE
CONFLUENCE BTWN THE SRN STREAM RIDGE AND NRN STREAM TROF OVER SE
CANADA WILL BE ONE OF THE MAIN PLAYERS IN THE WET WEATHER SETTING UP
ACROSS UPPER MI FOR THE NEXT 36-48HRS. WELL OUT AHEAD OF THE WRN
CONUS TROF...WAA/ISENTROPIC ASCENT REGIME SRPEADING OVER THE NRN
PLAINS HAS LED TO SCT -SHRA DEVELOPMENT FROM ND ACROSS NE MN
THIS AFTN. MID CLOUDS ARE PEELING SE FROM THAT AREA ACROSS UPPER MI.
ALTHOUGH CLOUDS HAVE WORKED TO SOMEWHAT LIMIT THE NORMAL DIURNAL
BUILDING OF MIXING HEIGHTS...SFC DWPTS HAVE STILL FALLEN DOWN INTO
THE SINGLE DIGITS/LOW TEENS ACROSS PORTIONS OF INTERIOR W AND CNTRL
UPPER MI.

A GOOD PATTERN FOR SOAKING RAINS WILL BE SETTING UP ACROSS THE AREA
OVER THE NEXT 36-48HRS AS FCST AREA WILL RESIDE IN A SHARP
BAROCLINIC ZONE RESULTING FROM COLD AIR SPREADING ACROSS SE CANADA
UNDER NRN STREAM TROF AND WARM AIR PUSHING TOWARD THE UPPER
MISSISSIPPI VALLEY AHEAD OF THE SRN STREAM WRN CONUS TROF. IN
FACT...MOST OF THE FCST AREA WILL SEE MDT TO HVY RAINFALL AMOUNTS BY
THE TIME THIS WET PERIOD WRAPS UP MON NIGHT. AFOREMENTIONED JET
STREAK WILL BE A KEY MECHANISM FOR PCPN GENERATION AS THE RIGHT
ENTRANCE WILL PROVIDE LARGER SCALE UPPER DIVERGENCE OVER THE AREA.
AT THE LOWER LEVELS...850MB FRONT SETTING UP IN THE VCNTY OF THE
MI/WI BORDER WILL PROVIDE A FOCUS FOR PCPN DEVELOPMENT UNDER
PERSISTENT FGEN/ISENTROPIC ASCENT. PRECIPITABLE WATER INCREASING TO
AROUND 1 INCH (200-250PCT OF NORMAL) WILL THEN SUPPORT THE EXPECTED
MDT/HVY PCPN AMOUNTS. UTILIZED A MIX OF ALL AVBL MODELS TO CONSTRUCT
POPS/PCPN AMOUNTS FOR TONIGHT/SUN AS MOST OF THE GUIDANCE IS FAIRLY
WELL CLUSTERED ON QPF AND TIMING ONSET OF RAIN. PCPN DEVELOPMENT
TONIGHT MAY BE DELAYED MORE SO THAN REFLECTED IN FCST DUE TO THE
VERY DRY AIR OVER THE AREA ATTM. BY 00Z MON...EXPECT PCPN AMOUNTS
RANGING FROM AROUND ONE-THIRD OF AN INCH OVER THE NRN KEWEENAW
PENINSULA AND NE LUCE COUNTY TO 0.90-1.25 INCHES OVER MUCH OF THE W
AND CNTRL FCST AREA. AS FOR TEMPS...LOWS TONIGHT SHOULD RANGE FROM
THE MID 30S TO LWR 40S...WARMEST FAR W. WITH EXPECTATION OF RAIN
PREVAILING FOR MUCH OF THE DAY IN MOST AREAS...LOWERED MAX TEMPS
SOME FOR SUN. HIGHS SHOULD RANGE FROM THE UPPER 30S NW AND NCNTRL TO
MAINLY THE LWR 40S ELSEWHERE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 401 AM EDT SAT APR 23 2016

LOOKS LIKE THE CHILLY...ACTIVE WX PATTERN IS STILL ON TRACK FOR LATE
THIS WEEKEND INTO EARLY NEXT WEEK AS A VERY TIGHT BAROCLINIC ZN WL
SETUP ACRS THE UPR GREAT LKS NEAR THE CONFLUENCE ZN BTWN NRN BRANCH
NW FLOW IN CANADA AND AN ACTIVE SRN BRANCH WSW FLOW OVER THE NRN
CONUS. SOME MDT TO HEAVY PCPN IS LIKELY TO FALL OVER AT LEAST THE S
HALF OF UPR MI...WHICH WL BE CLOSER TO A STNRY FNT RUNNING W-E THRU
THE UPR MIDWEST AND MOISTER AIR TO THE S. IF ENUF COLD AIR IN THE
NNE FLOW BTWN BLDG HI PRES INTO NRN ONTARIO AND THE LOWER PRES TO
THE S ADVECTS INTO THE CWA AND THIS AIR IS NOT EXCESSIVELY DRY...
THERE COULD BE SOME ACCUMULATING WET SN OVER MAINLY THE HIER TERRAIN
OF NW UPR MI FM LATE SUN NGT INTO MON NGT. BUT AS IS ALWAYS THE CASE
WHEN AN AREA IS NEAR THE NRN EDGE OF A PCPN AREA WITH PLENTY OF DRY
AIR JUST TO THE N...SMALL CHANGES IN THE FCST PARAMETERS MAY HAVE A
SGNFT IMPACT ON THE OUTCOME. AS THE ONTARIO HI PRES BLDS INTO THE
UPR LKS ON TUE...EXPECT QUITE BUT STILL RELATIVELY CHILLY WX INTO
MID WEEK. ANOTHER DISTURANCE/LO PRES MOVING NE FM THE PLAINS MAY
BRING MORE PCPN LATER WED/THU...BUT THERE IS GREAT UNCERTAINTY AS TO
WHETHER THE NW FLOW ALOFT ARND A DEEP UPR TROF CENTERED IN QUEBEC WL
SHUNT THIS SYSTEM TO THE S. THIS PERSISTENT DEEP TROF WL MAINTAIN
BLO NORMAL TEMPS FOR UPR MI THRU THIS WEEK.

SUN/MON...UPR MI IS FCST TO BE UNDER SHARP BAROCLINIC ZN UNDER
CONFLUENCE ZN BTWN COLD NRN BRANCH NW FLOW DOMINATING QUEBEC AND A
SRN BRANCH WSW FLOW OVER THE NRN CONUS. ALTHOUGH THE CONFLUENT UPR
FLOW WELL TO THE NE OF SLOW MOVING...STRONGER SRN BRANCH SHRTWV
RIDING ENEWD THRU THE NRN PLAINS WL TEND TO SHEAR OUT/WEAKEN THAT
SHRTWV AND OTHER DISTURBANCES THAT EJECT OUT AHEAD OF IT...MOST OF
THE MEDIUM RANGE MODELS GENERATE SOME MDT TO HEAVY PCPN OVER MAINLY
THE S HALF OF THE CWA. WAA TO THE N OF THE FNT...UPR DVGC IN RRQ OF
120KT H3 JET MAX JUST S OF JAMES BAY AS WELL AS SHARP...PERSISTENT
LO-MID LVL FGEN N OF THE H85 WARM/STNRY FNT STRETCHING E ACRS WI FM
LO IN THE NRN PLAINS AND AXIS OF PWAT AOA AN INCH /ABOUT 225 PCT OF
NORMAL/ OVER THE SRN CWA LOOK TO BE THE ENHANCEMENT FACTORS THAT WL
SUPPORT THIS HEAVIER PCPN AND OVERCOME THE NEGATIVES ASSOCIATED WITH
THE UPR CONFLUENCE. SOME OF THE MODELS SHOW AS MUCH AS 2-3 INCHES OF
PCPN FALLING OVER PORTIONS OF THE CWA DURING THE SUN THRU MON TIME.
SOME OF THE COLDER MODELS` FCST SDNGS/THERMAL FIELDS WITH H85 TEMPS
FALLING BLO 0C INDICATE AT LEAST SOME OF THE PCPN NEAR THE NRN EDGE
OF THE PCPN AREA WL FALL IN THE FORM OF SN AT TIMES. HOWEVER...
GUIDANCE HAS BEEN INCONSISTENT ON THE DEGREE OF COOLING AS WELL AS
THE IMPACT OF MUCH DRIER AIR THAT WL BE PRESENT JUST TO THE N AND
COULD ADVECT INTO THE CWA IN THE STEADY NNE FLOW TO THE S OF HI PRES
BLDG INTO NW ONTARIO. BEST CHC FOR SOME DRYING THAT MAY LIMIT
POPS/QPF AT LEAST TEMPORARILY LOOKS TO BE LATER ON SUN IN THE WAKE
OF A SHEARING DISTURBANCE PASSING TO THE E. THE BEST CHC FOR SOME
ACCUMULATING SN WL BE LATE SUN NGT INTO MON MRNG OVER THE HIER
TERRAIN OF THE W HALF WHEN THE SLOWLY APRCHG MAIN SHRTWV WL ENHANCE
UVV/DYNAMIC COOLING IN THE ABSENCE OF SOLAR WARMING...UNLESS LLVL
DRYING FM THE N NEGATIVELY IMPACTS PCPN POTENTIAL. NOT OUT OF THE
QUESTION THERE COULD BE A COUPLE INCHES OF WET...HEAVY SN IN THESE
AREAS. TEMPS THRU THIS TIME WL RUN BLO TO WELL BLO NORMAL...
ESPECIALLY THE MAX TEMPS.

MON NGT...AS THE SHRTWV RIDING TO THE NE BEGINS TO SHEAR OUT TO THE
ESE...LARGER SCALE DVNA/MID LVL DRYING/DEEP LYR QVECTOR DVGC IN ITS
WAKE WL TEND TO DIMINISH LINGERING PCPN NW-SE. WITH THE ARRIVAL OF
DRIER LLVL AIR ASSOCIATED WITH THE ONTARIO HI BLDG TOWARD THE UPR
LKS...SKIES MAY CLR OUT AS WELL AND ALLOW MIN TEMPS TO FALL WELL
INTO THE 20S.

TUE/TUE NGT...AS THE ONTARIO HI PRES EXPANDS INTO THE UPR LKS UNDER
CONFLUENT NW FLOW ALF BTWN DEEP UPR LO OVER QUEBEC AND AN APRCHG RDG
SHIFTING E THRU THE NRN PLAINS...EXPECT MOCLR SKIES. H85 TEMPS
RECOVERING TO NEAR 0C AND PLENTY OF SUNSHINE SHOULD ALLOW MAX TEMPS
TO RECOVER AT LEAST CLOSE TO 50 AWAY FM THE COOLING INFLUENCE OF THE
LKS. TUE NGT IS LIKELY TO BE ANOTHER CHILLY ONE WITH THE HI PRES
STILL DOMINATING.

WED/THU...ATTENTION WL THEN TURN TO WHETHER ANOTHER SRN BRANCH
SHRTWV MOVING NE THRU THE PLAINS WL IMPACT THE CWA DURING THE MID
WEEK. HOW FAR NE THIS DISTURBANCE/ACCOMPANYING PCPN WL MOVE WL
DEPEND ON THE STRENGTH OF THE PERSISTENT...DEEP CLOSED LO IN QUEBEC.
ALTHOUGH MANY OF THE MEDIUM RANGE MODELS BRING ASSOCIATED PCPN INTO
THE UPR LKS...SUSPECT THE DRIER RECENT CNDN MODELS ARE ON THE RIGHT
TRACK WITH A MORE CONFLUENT NW FLOW THRU ONTARIO ALLOWING A MORE
PERSISTENT SFC HI PRES RDG TO INFLUENCE THE UPR LKS AS SUGGESTED BY
THE 12Z GFS ENSEMBLE MEAN. BUT WL FOLLOW MODEL CONSENSUS GIVEN THE
MODEL SPREAD SO FAR OUT IN THE FCST PERIOD.

FRI...UPR RDGING/SFC HI PRES BLDG INTO THE UPR LKS WL BRING A RETURN
OF DRY AND SEASONABLE WX. WITH H85 TEMPS FCST WITHIN A FEW DEGREES
OF 0C...BLO NORMAL TEMPS WL CONTINUE.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT APR 23 2016

VFR CONDITIONS WILL LIKELY HOLD ON THRU THE EVENING AT
KIWD/KCMX/KSAW UNDER ONLY BKN-OVC MID LEVEL CLOUDS. LIGHT RAIN WILL
ARRIVE TONIGHT AND CONTINUE THRU SUN. CIGS WILL BEGIN TO STEADILY
LOWER OVERNIGHT AS STEADIER RAIN ARRIVES...REACHING IFR AT ALL
TERMINALS AROUND 12Z. CONDITIONS MAY CONTINUE TO DETERIORATE FURTHER
TO LIFR DURING THE MORNING HRS...PARTICULARLY AT KCMX/KSAW UNDER
UPSLOPE WINDS. VIS SHOULD MAINLY BE MVFR SUN MORNING...BUT COULD FALL
TO IFR AT TIMES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EDT SAT APR 23 2016

A CLASSIC SET UP FOR BRISK E TO NE WINDS IS SHAPING UP FOR LAKE
SUPERIOR OVER THE NEXT COUPLE OF DAYS AS HIGH PRES BUILDS INTO
NORTHERN ONTARIO AND A WEAK LOW PRES WAVE TRACKS ALONG A FRONT S OF
UPPER MI. WINDS INITIALLY UNDER 20KT THIS EVENING WILL SLOWLY RAMP
UP TONIGHT...MAINLY OVER WESTERN LAKE SUPERIOR. WINDS THEN INCREASE
MORE NOTABLY ACROSS THE LAKE SUN THRU MON MORNING...REACHING GALES
OVER FAR WESTERN LAKE SUPERIOR LATE SUN MORNING THRU MON AFTN AS
COASTAL CONVERGENCE/FUNNELING ENHANCE THE WINDS IN THAT AREA. A GALE
WARNING HAS BEEN POSTED FOR THAT PART OF THE LAKE. ACROSS THE REST
OF LAKE SUPERIOR...WINDS WILL INCREASE TO 20-30KT. WINDS WILL SLOWLY
DIMINISH MON NIGHT/TUE MORNING...BUT MORE SO TUE AFTN/NIGHT AS THE
NORTHERN ONTARIO HIGH PRES BUILDS INTO THE UPPER LAKES. E TO NE
WINDS GENERALLY UNDER 20KT WILL PREVAIL WED/THU. GIVEN THE E TO NE
WIND DIRECTION...WINDS WILL BE STRONGEST OVER WRN LAKE SUPERIOR ON
BOTH OF THOSE DAYS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WARNING FROM 11 AM EDT /10 AM CDT/ SUNDAY TO 8 PM EDT /7 PM
     CDT/ MONDAY FOR LSZ162.

LAKE MICHIGAN...
NONE.
&&

$$

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



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