Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 130525
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
125 AM EDT SAT SEP 13 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 336 PM EDT FRI SEP 12 2014

HAS BEEN A CLOUDY...COOL...AFTN WITH ISOLD-SCATTERED SHOWERS SLOWLY
EASING FROM WESTERN UPR MICHIGAN TO CNTRL UPR MICHIGAN. SHOWERS ARE
IN VCNTY OF SFC TROUGH FROM SOUTHEAST MINNESOTA OVER CNTRL WI AND
INTO CNTRL UPR MICHIGAN. SFC TROUGH IS TIED INTO H5-H3 TROUGH FM
DAKOTAS ACROSS MINNESOTA PER 12Z RAOBS. THOUGH WAVE WAS OPEN THIS
MORNING...IT IS EXPECTED TO DEEPEN AND EVEN CLOSE OFF BRIEFLY WHILE
CROSSING NORTHERN WI AND UPR MICHIGAN THIS EVENING INTO THE EARLY
MORNING HOURS ON SATURDAY. SOUNDINGS SHOW STEADY MOISTENING ABOVE H9
WITH LIFT OCCURRING H9-H5 AS THE WAVE DEEPENS. RESULTING MOISTENING
BLO H9 SHOULD BE PRETTY QUICK...ESPECIALLY CONSIDERING THERE IS
ALREADY SCT-BKN LOW CLOUDS FORMING OVER WEST AND CNTRL UPR MICHIGAN
DUE TO COOLER AIR IN LOW-LEVELS AND CONVERGENCE ALONG THE SFC
TROUGH. EXPECT AREA OF LGT RAIN MOVING NOW INTO CNTRL WI TO CONTINUE
TO EXPAND INTO CNTRL UPR MICHIGAN THIS EVENING. THE LGT RAIN ALONG
WITH TEMPS SETTLING INTO THE 40S WILL RESULT IN A DAMP AND CHILLY
EVENING. BASED ON OBS UPSTREAM IN NORTHWEST WI SHOWING MINIMAL
RAIN...DOES SEEM THERE WILL BE A SHARP GRADIENT TO THE WESTERN EDGE
OF THE RAIN...SO KEPT ONLY SLIGHT CHANCES FROM IWD TO CMX/P59. ONCE
THE RAIN ARRIVES OVER THE CNTRL CWA...IT SHOULD PERSIST THROUGH
MIDNIGHT OR EVEN INTO THE EARLY MORNING HOURS ON SATURDAY AS SYSTEM
CONTINUES TO DEEPEN AND SLOWLY SLIDE TO THE EAST. TRICKY IN HOW FAR
EAST TO CARRY THE WIDESPREAD RAIN AS THE GEM-REGIONAL INDICATES THAT
ONLY CNTRL CWA WILL BE AFFECTED BY H7 DEFORMATION ON NORTH EDGE OF
CLOSED OFF UPPER TROUGH. OTHER MODELS WERE A BIT MORE GENEROUS IN
SHOWING BETTER FORCING HEADING TO THE EAST CWA BY AROUND MIDNIGHT.
WENT WITH SOME LIKELY POPS TOWARD KERY AFTER MIDNIGHT...BUT DID KEEP
HIGHEST POPS OVER CNTRL THIS EVENING...AFFECTING ISHPEMING...
MARQUETTE IRON MOUNTAIN...ESCANABA AND MENOMINEE. ENE WINDS THROUGH
H85 WILL ONLY ADD TO LIFT FOR HIGHER TERRAIN OF NCNTRL.

DID LOOK INTO THE POSSIBILITY OF SOME SNOW FLURRIES MIXING WITH THE
RAIN GIVEN A REPORT EARLIER TODAY OF GRAUPEL WITH THE SHOWERS OVER
THE WESTERN U.P. AND SINCE WE ALSO HAD FLURRIES REPORTED LAST NIGHT
OVER WESTERN UPR MICHIGAN AND THURSDAY AFTN OVER SOUTH CENTRAL U.P.
OVERALL FOR TONIGHT...THOUGH IT IS PLENTY COLD ALOFT AS THERMAL
TROUGH AT H7-H5 IS PRESENT WITH H5 TEMPS DOWN TO -30C AND THERE WILL
BE ICE CRYSTALS GENERATED ALOFT...WBZERO HEIGHTS OF 1500-2000 AGL ARE
TOO HIGH TO SUPPORT ANY MIX OF RAIN/SNOW. IF WE SEE HEAVIER SHOWERS
WITHIN THE STEADIER RAIN AREA...SUPPOSE SOME GRAUPEL MAY OCCUR.

BASED ON CONSENSUS OF MODEL SOUNDINGS...DROPPED POPS OVER CNTRL CWA
BTWN 09Z-12Z AS SUPPORT FOR MID LEVEL LIFT CUTS OUT BY THAT TIME ONCE
THE UPPER TROUGH SLIDES EAST. LINGERED AT LEAST LOW CHANCES TIL
AROUND 12Z IN FAR EAST CWA AT KERY THOUGH. THINNING CLOUDS FOR CNTRL
AND EAST CWA...BUT DO EXPECT SKIES TO STAY BKN-OVC THROUGH DAYBREAK.

FARTHER WEST...EXPECT SKIES TO CLEAR OUT OVER WESTERN UPR MICHIGAN
BY LATE EVENING OR MAYBE AS LATE AS AFTER MIDNIGHT. PWATS AGAIN ARE
DOWN TO LESS THAN 50 PCT OF NORMAL AND UPSTREAM DWPNTS IN NORTHEAST
MINNESOTA ARE IN THE 20S TO AROUND 30 DEGREES. WINDS WILL BE
LIGHT...SO SIMILAR TO LAST NIGHT...WILL ONLY TAKE A FEW HOURS OF
CLEAR SKIES TO ALLOW TEMPS TO PLUMMET. NOT QUITE SURE ON EXTENT OF
CLEARING THOUGH. MINS DROPPING TO AROUND 32 DEGREES WITH WIDESPREAD
FROST DOES SEEMS LIKELY SO WILL ISSUE A FROST ADVY FOR WESTERN UPR
MICHIGAN. DID NOT HAVE ENOUGH CONFIDENCE TO ISSUE FREEZE WARNING
THOUGH AS NOT COMPLETELY SURE THAT SKIES WILL TOTALLY CLEAR OUT
AS THE SYSTEM TO THE EAST WILL ONLY SLOWLY BE FILLING. DID NOT
BRING DICKINSON OR MARQUETTE INTO THE FROST ADVISORY RIGHT NOW
THINKING THERE WILL ENOUGH CLOUD COVER LATER TONIGHT TO PROHIBIT
IDEAL RADITIONAL COOLING.

IMPROVING TREND EXPECTED ON SATURDAY AS UPPER TROUGH EXITS EAST IN
THE MORNING AS STRONGEST H5-H3 WINDS SLIDE OUT AHEAD OF THE TROUGH.
MID TO UPR RIDGING WORKS IN BY MIDDAY...BUT COULD STILL BE FAIR
AMOUNT OF 5-8KFT STRATOCU LEFTOVER DUE TO SUBSIDENCE ALOFT TRAPPING
THE MOISTURE. ONSHORE FLOW MOST PRONOUCED IN THE MORNING NEAR LK
SUPERIOR EAST OF MQT-MUNISING. OTHERWISE...MIXING TO H9-H875
SUPPORTS MAX TEMPS ON SATURDAY IN THE LOW-MID 50S. EVEN IF THE LOW
CLOUDS BEGIN TO SCATTER OUT...SHOULD SEE INCREASING HIGH CLOUDS
AHEAD OF WEAK SHORTWAVE TROUGH DROPPING ACROSS THE DAKOTAS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 451 PM EDT FRI SEP 12 2014

DURING THE LONG TERM...A RIDGE WILL PREVAIL OVER WRN NAMERICA WITH
DOWNSTREAM TROF OVER ERN NAMERICA. RESULTING NW FLOW WILL SPELL A
GENERALLY QUIET/COOL PERIOD OF EARLY FALL WEATHER FOR THE UPPER
GREAT LAKES. TEMPS ON MOST IF NOT ALL DAYS WILL BE BLO NORMAL.
HEADING INTO NEXT WEEKEND...PATTERN WILL BE DEAMPLIFYING...AND THIS
WILL ALLOW FOR WARMER WEATHER TO RETURN...AT LEAST TEMPORARILY. AS
FOR PCPN...NOT MUCH IS IN THE OFFING. IT APPEARS THERE WILL BE 2
COLD FROPAS NEXT WEEK...AND THESE WILL OFFER SOME OPPORTUNITY FOR
PCPN. ANY PCPN THAT DOES OCCUR WILL BE LIGHT DUE TO LACK OF MOISTURE
RETURN. DEPENDING ON HOW AGGRESSIVE THE WARMING IS AT THE END OF THE
WEEK AND HOW QUICKLY THE NEXT SHORTWAVE MOVES E IN THE DEAMPLIFYING
FLOW...ANOTHER SHOT AT PCPN IS POSSIBLE FRI.

BEGINNING SAT NIGHT...NEXT SHORTWAVE TROF WILL BE DROPPING INTO THE
NRN PLAINS. ALTHOUGH WAA GETS UNDERWAY...THERE IS LITTLE IN THE WAY
OF ISENTROPIC ASCENT. WITH BEST DEEP LAYER FORCING W OF HERE THRU
THE NIGHT...DRY FCST LOOKS ON TRACK. IT SHOULD BE ANOTHER COOL
NIGHT...ESPECALLY IF DIURNALLY AIDED CLOUDS FROM THE AFTN DISSIPATE
QUICKLY. SOME INCREASE IN HIGH CLOUDS OVER THE W ALONG WITH
TIGHTENING PRES GRADIENT/WINDS AHEAD OF THE NEXT SHORTWAVE
TROF SHOULD WORK TO KEEP TEMPS FROM FALLING TOO MUCH OVER THE W.
OUTSIDE OF TRADITIONAL COLD SPOTS WHICH MIGHT SLIP TO OR JUST BLO
FREEZING...MOST AREAS SHOULD STAY ABOVE FREEZING SAT NIGHT.

SUN/SUN NIGHT...APPROACHING SHORTWAVE TROF WILL MOVE ACROSS THE
UPEPR GREAT LAKES. MOST OF THE MODELS INDICATE THAT THE BEST MOISTURE
AND UPWARD MOTION WILL STAY NORTH OF THE AREA ALONG AND N OF THE
PROJECTED VORT TRACK. TIMING AMONG THE MODELS IS QUITE SIMILAR AND
SUGGESTS CHC POPS SPREADING ACROSS ROUGHLY THE W HALF OF UPPER MI...
MAINLY DURING THE AFTN HRS. SLIGHTLY FASTER MODEL TREND IS NOTED...
AND THIS SHOULD RESULT IN PCPN CHC ENDING W TO E SUN NIGHT.

DRY WEATHER SHOULD RETURN FOR MON. SOME OF THE MODEL GUIDANCE IS
SUGGESTING SPOTTY LIGHT PCPN MON IN ASSOCIATION WITH THERMAL TROF
ALOFT. RETAINED A DRY FCST...BUT IT WILL BE SOMETHING TO TAKE A LOOK
AT AGAIN IN UPCOMING FCSTS.

HEADING INTO MIDWEEK...MEDIUM RANGE GUIDANCE SHOWS NOTABLE
DIFFERNCES WITH THE EXPECTED SECOND COLD FRONT PASSAGE. GFS/UKMET
ARE MORE AMPLIFIED WITH THE NEXT BATCH OF ENERGY HEADING SSE TO
HUDSON BAY/NRN ONTARIO VCNTY MON/TUE. AS A RESULT...ASSOCIATED COLD
FRONT DROPS THRU UPPER MI TUE AFTN/EVENING. THE ECMWF DOESN`T DRIVE
ENERGY AS FAR S AND WAITS FOR A FOLLOWING SHORTWAVE TO PUSH COLD
FRONT THRU UPPER MI WED. THE GEM WAS SIMILAR TO THE ECMWF...BUT THE
12Z RUN TRENDED SIGNIFICANTLY FASTER...TO THE POINT THAT IS EVEN
SLIGHTLY FASTER THAN THE GFS. THE GFS HAS BEEN VERY CONSISTENT WITH
ITS SOLUTION WHILE THE ECMWF HAS SHOWN SOME DIFFERENCES. TODAYS 12Z
RUN HAS TRENDED A LITTLE FASTER WITH THE FRONT. WITH BULK OF
GUIDANCE FAVORING THE FASTER FRONT AND WITH A SLIGHTLY FASTER TREND
NOTED IN THE 12Z ECWMF...FCST WILL LEAN TOWARD THE GFS TODAY.
FORTUNATELY...PCPN POTENTIAL WITH FRONT IS QUITE LIMITED AND DOESN`T
WARRANT A MENTION AT THIS POINT...SO TIMING OF FRONT DOESN`T IMPACT
PCPN FCST. TEMPS WILL BE THE MORE NOTICEABLE IMPACT AS MID DAY 850MB
TEMPS OVER THE FCST AREA ON WED RANGE FROM -2C WITH THE GFS TO 6-8C
WITH THE ECMWF. TRENDED TEMPS SOMEWHAT COOLER FOR WED...BUT DID NOT
GO NEARLY AS LOW AS THE GFS SUGGESTS AS IT IS PROBABLY OVER
AMPLIFIED AND TOO STRONG WITH THE COLD AIR PUSH S.

DRY WEATHER SHOULD CONTINUE THRU THU...AND THEN AS MENTIONED
EARLIER...PCPN MAY RETURN FRI DEPENDING ON STRENGTH OF DEVELOPING
WAA PATTERN AND HOW QUICKLY NEXT SHORTWAVE SHIFTS E IN DEAMPLIFYING
FLOW REGIME. UTILIZIED A SIMPLE MODEL CONSENSUS WHICH BRINGS CHC
POPS INTO ALL BUT THE ERN FCST AREA FRI.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 124 AM EDT SAT SEP 13 2014

CONDITIONS WILL STAY VFR FOR THIS FORECAST PERIOD. A BKN VFR CLOUD
DECK SHOULD REMAIN AT KCMX AND KSAW THROUGH THE TAF PERIOD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 336 PM EDT FRI SEP 12 2014

WINDS MAINLY BLO 20 KTS THROUGH EARLY NEXT WEEK AS PRESSURE GRADIENT
IS WEAK. COLD FRONT MOVES THROUGH TUESDAY OR WEDNESDAY. COULD SEE
WINDS 20 TO 30 KTS IN WAKE OF THIS FRONT. NO GALES EXPECTED AT THIS
TIME.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR
     MIZ002>004-009-010-084.

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

$$

SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...07
MARINE...JLA





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