Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 112308
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
708 PM EDT THU SEP 11 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 405 PM EDT THU SEP 11 2014

COOL TROUGH ALOFT EXTENDS FM EASTERN CANADA INTO THE CENTRAL
ROCKIES. RAIN AND DRIZZLE IN THE CYCLONIC FLOW OF THE DEPARTING LOW
PRESSURE SYSTEM IS FINALLY BEGINNING TO WANE OVER UPR MICHIGAN. VIS
SATELLITE INDICATES A HEALTHY AMOUNT OF STRATUS AND STRATOCU THOUGH
AS H925-H85 THERMAL TROUGH WITH H85 TEMPS DOWN TO -2C IS ROTATING
ACROSS THE LK SUPERIOR REGION. HIGHER PRESSURES BEGIN TO SLIDE
ACROSS THIS EVENING AND LATER TONIGHT. SINCE THE CLOUDS ALREADY
SHOW A CELLULAR LOOK TO THEM AND THE RIDGE IS BUILDING IN...THINK
THERE IS GOOD SHOT AT SOME CLEARING LATER THIS EVENING...ESPECIALLY
WESTERN CWA AWAY FM LK SUPERIOR. TEMPS UPSTREAM THIS MORNING WERE IN
THE UPR 20S TO MID 30S...SO IF SKIES DO CLEAR OUT...THINK THERE WILL
BE POTENTIAL FOR FROST. INSTEAD OF HANDLING WITH SPS THINK THE POTENTIAL
IS HIGH ENOUGH TO GO AHEAD AND PUT OUT A FROST ADVISORY. COORDINATED
THIS WITH WFO GRB. LOWEST TEMPS AND HEAVIEST FROST SHOULD BE AWAY
FM THICKER CLOUDS NEAR LK SUPERIOR OVER THE WEST HALF...ROUGHLY FM
WAKEFIELD AND MARENISCO TO IRON RIVER AND CRYSTAL FALLS...AND INTO
NORTHERN DICKINSON COUNTY IN THE CHANNING AND FELCH AREAS. PATCHY
FROST POSSIBLE NORTH AND EAST OF THESE AREAS...BUT NOT ENOUGH
COVERAGE TO ISSUE ADVY. ELSEHWERE EXPECT MIN TEMPS TONIGHT FROM MID
TO UPR 30S TO NEAR 40...WARMEST NEAR LK SUPERIOR IN THE EAST.

POCKET OF H8-H7 MOISTURE CURRENTLY OVER ONTARIO IS SUPPOSED TO SLIDE
ACROSS WESTERN LK SUPERIOR AND CNTRL LK SUPERIOR OVERNIGHT INTO
FRIDAY MORNING. NEUTRAL TO SLIGHTLY CYCLONIC ONSHORE FLOW IN
LOW-LEVELS AND ENOUGH OVER-WATER INSTABILITY WITH WATER TEMPS OVER
WESTERN AND CNTRL LK SUPERIOR /UPR 40S MID LAKE TO MID 50S
NEARSHORE/ SHOULD ALLOW FOR ISOLD LAKE EFFECT RAIN SHOWERS WHERE SFC
WINDS ARE MOST CONVERGENT. BEST CHANCE OF THIS WOULD BE BTWN LITTLE
GIRLS POINT AND THE UPPER ENTRANCE OF PORTAGE CANAL...VCNTY OF
ONTONAGON...AND ALSO JUST TO THE EAST OF MARQUETTE TO MUNISING.

SHORTWAVE MOVING OUT OF THE NORTHERN PLAINS AND ASSOCIATED DEEP
LAYER Q-VECTOR CONVERGENCE SPREADS ACROSS UPR LAKES ON FRIDAY AFTN.
SOUNDINGS INDICATE THERE WILL BE DRY AIR BLO H9 BUT THERE IS ALSO A
LOT OF MOISTURE AND LIFT ABOVE THIS LAYER. THINK THAT THERE WILL BE
AN INCREASE OF MID-UPR LEVEL CLOUDS MID TO LATE MORNING WITH ENOUGH
MOSITURE AND LIFT TO RESULT IN RAIN AT LEAST INTO THE SOUTHERN PART
OF CWA MID-LATE AFTN. NORTH TO NORTHEAST WINDS WILL ALSO PROVIDE
UPSLOPE LIFT INTO WESTERN AND NCNTRL UPR MICHIGAN AND MAY ALLOW THE
SHOWERS TO EXPAND EVEN AHEAD OF THE LARGER SCALE ARRIVAL OF RAIN
SHOWERS. MODELS ARE LATCHED ONTO THIS SIGNAL GIVEN THE STRONGER
SHORTWAVE...SO CONTINUED TO BUMP POPS UPWARD...WITH LIKELY POPS BY
LATE DAY OVER THE SCNTRL. THE CLOUDS AND LGT RAIN WILL KEEP TEMPS
ON THE LOWER SIDE...NEAR 50 WEST HALF AND IN THE MID 50S EAST
HALF.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 349 PM EDT THU SEP 11 2014

INVERTED SFC TROUGH AND UPPER WAVE MOVES THROUGH THE AREA FRI NIGHT.
THE MODELS SUGGEST A SLIGHTLY SLOWER MOVEMENT OF THIS UPPER TROUGH.
THE AREA OF BEST Q-VECT CONV PERSISTS OVER THE EASTERN HALF IN THE
EVENING THEN MOVES EAST OF THE REGION OVERNIGHT WITH THE PASSAGE OF
THE UPPER TROUGH. THIS AT FIRST WOULD SUGGEST THAT ANY SHOWER
ACTIVITY WOULD END LATE FRI NIGHT INTO SAT MORNING. HOWEVER...WITH
850MB TEMPS AROUND -2C...THE EXPECTATION IS THAT THERE WILL BE AT
LEAST SOME LIGHT LAKE EFFECT RAIN SHOWERS/DRIZZLE EAST OF MARQUETTE
AS LOW LEVEL MOISTURE PERSISTS AND ONSHORE NW FLOW DEVELOPS. AS
SUCH...WILL HANG ONTO LOW POPS ACROSS THE EAST LATER FRI NIGHT INTO
SATURDAY MORNING UNTIL THE STRONG SUBSIDENCE FROM THE SFC RIDGE
BUILDS IN BY SAT AFTN. WITH ALL THAT SAID...WILL CONTINUE WITH
CHANCE POPS ACROSS THE EASTERN 2/3 FRI NIGHT...THEN CONTINUE WITH
CHANCE POPS ACROSS THE EASTERN LAKESHORE SAT MORNING.

REGARDING FROST POTENTIAL FRIDAY NIGHT/SAT MORNING...WITH THE
SLIGHTLY SLOWER MOVEMENT OF THE UPPER WAVE...THERE WILL LIKELY BE
MORE CLOUDS AROUND DURING THE OVERNIGHT HOURS. HOWEVER...THE NWP
SUGGEST THAT LOW AND MID LEVEL MOISTURE SCOURS OUT OVER THE WEST
AFTER MIDNIGHT WHICH SHOULD ALLOW FOR CLEARING ESPECIALLY WITH THE
UPPER RIDGE BUILDING ACROSS THE REGION. AS SUCH...LOW TEMPS IN THE
UPPER 20S/LOWER 30S ARE NOT OUT OF THE QUESTION WITH FROST CERTAINLY
POSSIBLE.

EXPECT ANY REMAINING SHOWERS TO END BY SAT AFTN. ALTHOUGH TEMPS WILL
CONTINUE BELOW NORMAL...IT SHOULD END UP BEING A PARTLY TO MOSTLY
SUNNY AFTERNOON WITH HIGH PRESSURE REMAINING OVERHEAD AND
PRECIPITABLE WATER VALUES BELOW 0.40 INCH. ANOTHER COOL NIGHT ON
SATURDAY NIGHT...BUT HIGH CLOUDS STREAMING INTO THE AREA AHEAD OF
THE NEXT UPPER WAVE WILL LIKELY KEEP ALL AREAS ABOVE FREEZING.

ON SUNDAY...THE NEXT SYSTEM WILL RAPIDLY APPROACH THE AREA IN THE
FAST FLOW ALOFT. THE ECMWF AND GFS SUGGEST THAT THE BEST MOISTURE
AND UPWARD MOTION ASSOCIATED WITH THE UPPER VORT WILL STAY NORTH OF
THE AREA. THE MODELS ARE A LITTLE FASTER WITH ANY PCPN ACROSS THE
UP...WITH THE NAM...GFS AND ECMWF ALL SHOWING LIGHT PCPN MOVING INTO
THE WESTERN 1/3 OF THE FORECAST AREA IN THE AFTERNOON. AS
SUCH...HAVE INCREASED POPS TO THE CHANCE CATEGORY ACROSS THE FAR
WEST. HOWEVER...WILL CONFINE THESE CHANCE POPS TO THE FAR WEST AS
THE DRY ATMOSPHERE AHEAD OF THE SYSTEM MAY BE ENOUGH TO HOLD PCPN
FROM MOVING EAST TOO QUICKLY.

FOR THE EXTENDED...EXPECT THE HUDSON BAY TROUGH TO PERSIST THROUGH
THE PERIOD KEEPING NW FLOW ACROSS THE AREA THROUGH THE PERIOD. THIS
SHOULD ALLOW FOR TEMPS TO STAY BELOW NORMAL ACROSS THE AREA.
OTHERWISE...THE WEATHER SHOULD STAY FAIRLY QUIET. MAY CONTINUE WITH
SOME LINGERING SHOWERS ON MONDAY WITH THE TROUGH OVERHEAD.
BUT...WITH SURFACE HIGH PRESSURE IN CONTROL DO NOT EXPECT MUCH MORE
THAN ISOLATED SHOWERS. A WEAK COLD FRONT IS EXPECTED TO MOVE THROUGH
THURSDAY...BUT THE GFS AND ECMWF SUGGEST A DRY FORECAST WITH THE
BEST MOISTURE/LIFT REMAINING NORTH.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 708 PM EDT THU SEP 11 2014

THE ABUNDANT MOISTURE WILL RESULT IN SCT-BKN VFR CLOUDS THROUGH THE
PERIOD AT IWD AND CMX AND MAINLY BKN MVFR CLOUDS AT SAW. LAKE EFFECT
RAIN SHOWERS ARE POSSIBLE OVERNIGHT INTO FRIDAY MORNING AT IWD AND
CMX...BUT COVERAGE AND DURATION IS LIMITED ENOUGH TO KEEP OUT OF
TAFS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 405 PM EDT THU SEP 11 2014

RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER LAKES INTO NEXT
WEEK...SO WINDS WILL BE NO HIER THAN 20 KTS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT FRIDAY FOR
     MIZ009>011.

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

$$

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





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