Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 231030
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
630 AM EDT SAT APR 23 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SAT APR 23 2016

WV LOOP AND 00Z RAOBS/ANALYSIS INDICATE WNW FLOW ALOFT ACROSS GREAT
LAKES BETWEEN UPPER LOW OVER HUDSON BAY AND TROUGH CROSSING WESTERN
CONUS. ON LEADING EDGE OF TROUGH...SFC LOW IS FORMING WITH WARM AIR
ADVECTION SFC-H85. THE H85 TEMP GRADIENT IS IMPRESSIVE WITH +22C AT
RAPID CITY SD AND -1C AT INTERNATIONAL FALLS MN. BAROCLINIC ZONE AND
ASSOCIATED H85-H7 FRONTOGENESIS ALONG WITH UPPER DIVERGENCE TIED TO
RIGHT ENTRANCE REGION OF 100+ KT JET STREAK FM NORTHERN ONTARIO TO
SOUTHERN QUEBEC WILL SUPPORT INCREASING MID CLOUDS TODAY WITH SMALL
CHANCE OF RAIN OVER FAR NORTHWEST CWA...INCLUDING THE KEWEENAW.
ELSEWHERE...WILL BE ANOTHER DAY OF DRYING AS DESPITE THE INCREASE IN
CLOUDS...AFTN TEMPS NEAR 60 DEGREES OVER INTERIOR WEST. RH VALUES IN
THOSE AREAS MAY DROP BLO 30 PCT. LIGHT WINDS LESS THAN 10 MPH WILL
MITIGATE ANY FIRE WEATHER CONCERNS.

RAIN CHANCES INCREASE MARKEDLY TONIGHT FROM WEST TO EAST AS FGEN AND
UPPER DIVERGENCE PERSIST BUT ARE ENHANCED BY INCREASING ISENTROPIC
ASCENT TO THE NORTH OF SHARPENING SFC LOW AND QUASISTATIONARY FRONT
FM DAKOTAS TO WESTERN WI AND ALSO AS SHORTWAVE CURRENTLY OVER
EASTERN MONTANA REACHES THE UPPER GREAT LAKES. TRENDED SLOWER ON
BRINGING THE WIDESPREAD RAIN IN TONIGHT. NAM/GFS SOUNDINGS INDICATE
DRY AIR LINGERING BLO H7 WILL KEEP IT DRY FM ESCANABA AND MUNISING
TO NEWBERRY UNTIL AFTER MIDNIGHT. MODELS HINT AT HEAVIER QPF MAYBE
OVER 0.50 INCH SOMEWHERE OVER WEST AND SOUTHWEST CWA AFTER MIDNIGHT.
HEAVIER RAIN LIKELY WILL OCCUR WHERE ISENTROPIC ASCENT 300-315K /H8-
H5/ ENDS UP STRONGEST. BEST BET ON THAT NOW IS SOMEWHERE ALONG WI
BORDER. TEMPS WILL BE WARMER THAN EARLY THIS MORNING WITH THE CLOUDS
AND RAIN AROUND. EXPECT READINGS MAINLY IN THE MID TO UPPER 30S WITH
LOW 40S OVER FAR WEST.

.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 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 629 AM EDT SAT APR 23 2016

VFR CONDITIONS SHOULD HOLD THROUGH MIDNIGHT TONIGHT WITH SCT-BKN MID
CLOUDS. LIGHT RAIN MOVES IN AFTER MIDNIGHT AND CONDITIONS SHOULD
QUICKLY BECOME IFR TOWARD DAYBREAK AT ALL THE TAF SITES DUE TO
LOWERING CIGS. VSBY STAYS MOSTLY UNRESTRICTED EVEN AS RAIN
BEGINS...BUT COULD LOWER TO MVFR OVER SW UPR MICHIGAN LATE
TONIGHT WHERE HEAVIER RAIN IS EXPECTED.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 401 AM EDT SAT APR 23 2016

LIGHT WINDS ASSOCIATED WITH PASSING HI PRES WILL BECOME NE BEGINNING
TONIGHT BETWEEN A LO PRES DEVELOPING IN THE NCENTRAL PLAINS AND
ANOTHER HI PRES BUILDING INTO NORTHERN ONTARIO. AS THE LO PRES MOVES
SLOWLY CLOSER AND THE PRES GRADIENT TIGHTENS OVER THE UPPER LAKES...
EXPECT THE NE WINDS TO INCREASE UP TO 25 TO 30 KTS AND PERSIST INTO
MON. THE WINDS WILL BE STRONGER AND UP TO GALE FORCE OVER THE FAR
WESTERN PORTION OF THE LAKE...WHERE THE NE FLOW WILL BE ACCENTUATED
BY THE COASTLINE CONFIGURATION. OPTED TO ISSUE A GALE WATCH FOR THE
FAR WESTERN LSZ162 FOR SUN MORNING THRU MON AFTERNOON. WINDS WILL
BEGIN TO DIMINISH BEGINNING MON NIGHT AS THE ONTARIO HI PRES BUILDS
INTO THE UPPER LAKES. LIGHTER ENE WINDS UNDER 20 KTS WILL THEN
PREVAIL ON TUE/WED.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR
     LSZ162.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...KC
AVIATION...JLA
MARINE...KC



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