Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 051937
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
337 PM EDT SUN JUL 5 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 337 PM EDT SUN JUL 5 2015

WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A CLOSED MID LEVEL LOW
OVER NRN MANITOBA WITH TROF AXIS EXTENDING WSW INTO SRN ALBERTA.
SFC COLD FRONT EXTENDING FROM NRN ONTARIO INTO NRN MN SUPPORTING
CONVECTION OVER NRN MN IN ENVIRONMENT OF 1500 J/KG MLCAPE. SFC HIGH
PRES CONTINUES TO DOMINATE OVER THE UPPER GREAT LAKES KEEPING
WEATHER DRY. HIGH TEMPS REACHED INTO THE 80S ACROSS MUCH OF THE AREA
THIS AFTERNOON IN SOUTHERLY FLOW...EXCEPT DOWNWIND OF LAKE MICHIGAN
WHERE TEMPS STAYING SLIGHTLY COOLER WITH MODERATION OFF THE LAKE.

TONIGHT...AS LOW-LEVEL JET...AXIS OF MODEST ELEVATED INSTABILITY AND
THETA-E AXIS SHIFTS E TONIGHT AHEAD OF SFC COLD FRONT FORECAST TO
REACH FAR WRN LAKE SUPERIOR BY 12Z MON...SHRA/TSRA WILL SLOWLY
SPREAD E TOWARD THE AREA. CONSENSUS OF MODEL GUIDANCE SUGGESTS
BRINGING PCPN CHC ONLY INTO FAR WRN UPPER MI OVERNIGHT TONIGHT.
INCREASING COLUMN MOISTURE AND WINDS WILL KEEP TEMPS UP. EXPECT MINS
IN THE MID/UPPER 60S W AND UPPER 50S/LWR 60S E.

MONDAY...FOCUS WILL BE ON TIMING OF COLD FRONT AND ASSOCIATED
SHRA/TSRA MOVING THROUGH THE AREA AND THREAT OF ANY STRONGER TO
SEVERE STORMS. MODELS INDICATE THE MAIN SHORTWAVE DRIVING FRONTAL
TIMING WILL BE LIFTING FROM ND MON MORNING THROUGH NRN MN AND NRN
ONTARIO MON AFTERNOON INTO NRN ONTARIO MON NIGHT. AT SAME TIME...A
SFC LOW/WAVE WILL BE RIDING ALONG THE FRONTAL BOUNDARY FM MN INTO NW
WI AND WRN UPPER MI AND CENTRAL/ERN LAKE SUPERIOR. EXPECT WIDESPREAD
SHOWERS AND SOME TSRA ALONG THE ADVANCING FRONT DUE TO HEIGHT FALLS
UP TO 70M AHEAD OF SHORTWAVE...STRONG DEEP LAYER Q-VECTOR
CONVERGENCE AND INCREASING 250-300 MB DIVERGENCE IN RIGHT ENTRANCE
REGION OF UPPER JET STREAK EXITING BASE OF TROUGH AND LIFTING INTO
NRN ONTARIO. CATEGORICAL POPS STILL ON TARGET...SLIDING FM WEST TO
EAST. MOISTURE ADVECTION INTO THE VCNTY OF THE FRONT IS IMPRESSIVE
WITH ALL MODELS SHOWING H85 DWPNTS OVER +15C AND STRONG 850 MB
MOISTURE TRANSPORT ALONG THE FRONT ALONG WITH PWATS PUSHING OVER 2
INCHES. GIVEN ABUNDANT MOISTURE...HEAVY RAIN WILL BE A THREAT WITH
THUNDERSTORMS FORMING ALONG THE FRONT...ESPECIALLY WITH FREEZING
LEVELS NEAR 14KT LIKELY CONTRIBUTING TO WARM RAIN PROCESSES. SWIFT
STORM MOTIONS OVER 40 KTS WILL LIMIT POTENTIAL FOR PROLONGED HEAVY
RAIN.

MODELS STILL SHOWING SOME DIFFERENCES IN TIMING OF FRONT AND PCPN
BUT THE BIGGER DIFFERENCES REMAIN IN EXTENT OF INSTABILITY AHEAD OF
THE FRONT DURING PEAK HEATING ON MONDAY AFTERNOON /18Z AND 21Z/. 12Z
NAM REMAINS AN OUTLIER WITH SFC CAPES NEARING 2000J/KG FOR SCNTRL BY
21Z WHILE GFS/ECMWF/GEM-REGIONAL/SREF SHOW CLOSER TO 500J/KG. NAM
FCST SFC DWPNTS IN THE LOWER TO MID 70S AHEAD OF FRONT LOOK WAY
OVERDONE BASED ON UPSTREAM OBSERVED DEWPOINTS AND ARE PROBABLY
CONTRIBUTING TO INFLATED CAPE VALUES. MOST OF THE OTHER MODELS
INDICATE DEWPOINTS IN THE MID TO UPPER 60S...MAYBE APPROACHING 70F
FAR SCNTRL.

MODELS STILL SHOW STRONG WIND FIELDS WITH THIS SYSTEM. AHEAD OF THE
FRONT...MODEL SOUNDINGS WITHIN THE MIXED LAYER STILL SHOW THE
POTENTIAL FOR 40 MPH WIND GUSTS MONDAY OVER THE EASTERN CWA AS THEY
SHOULD HAVE THE LONGEST PERIOD OF SUNSHINE/DIURNAL HEATING. AS FOR
WINDS ASSOCIATED WITH TSRA THAT FORM...DEEP LAYER SHEAR VALUES OF 40
TO 50 KNOTS WOULD EASILY BE SUFFICIENT FOR STRONGER TO POSSIBLY
SEVERE STORMS IF INSTABILITY ENDS UP BEING A BIT HIGHER THAN MODEL
CONSENSUS FCST. JUST NOT SURE AT THIS POINT IF THAT WILL
HAPPEN...AND THAT WILL LIKELY BE THE BIGGEST LIMITING FACTOR FOR
SEVERE STORM POTENTIAL. NONETHELESS...GIVEN THE STRENGTH OF WINDS
THROUGH SOUNDING PROFILE...CAN`T ARGUE TOO MUCH WITH SPC DAY 2
OUTLOOK OF KEEPING A MARGINAL RISK OF SEVERE STORMS FOR MUCH OF THE
AREA...AS THERE WOULD BE A POTENTIAL OF BRINGING DAMAGING WINDS TO
SFC WITH DOWNWARD MOMENTUM TRANSFER FROM HEAVY PCPN LOADING WITH
STORMS.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 318 PM EDT SUN JUL 5 2015

MAIN IMPACTS WILL OCCUR IN THE FIRST 6-12 HOURS OF THE
FORECAST...WHICH STARTS 00Z TUE. A POTENT SHORTWAVE WILL BE JUST NW
OF THE CWA AT 00Z TUE...BUT A ROUGHLY 1002MB SFC LOW WILL BE OVER
NERN LAKE SUPERIOR WITH A STRONG COLD FRONT ABOUT HALF WAY DONE WITH
AN E-W TRANSIT OF UPPER MI. HEAVY RAIN ASSOCIATED WITH SHOWERS AND
THUNDERSTORMS WILL BE MAINLY ALONG AND BEHIND THE COLD FRONT AND ALL
PRECIP SHOULD BE E OF THE CWA BY SHORTLY BEFORE 12Z TUE. THERE WILL
BE A SEVERE THREAT...ALTHOUGH THE DETAILS OF SUCH ARE STILL QUITE
UNCERTAIN...BUT IT WILL NOT TAKE MUCH TO MIX POSSIBLY DAMAGING WINDS
TO THE SFC DUE TO STRONG LOW-MID LEVEL WINDS AND PRECIP LOADING IN
CONVECTION. SEE THE SHORT TERM DISCUSSION FOR MORE DETAILS ON SEVERE
THREAT...BUT THINKING THREAT WILL DIMINISH AS CONVECTION MOVES INTO
ERN UPPER MI WHERE BOUNDARY LAYER WILL BE MODIFIED BY FLOW OFF LAKE
MICHIGAN. QPF AMOUNTS BETWEEN 00Z AND 12Z TUE LOOK TO GENERALLY BE
BETWEEN 0.50 AND 1.00 INCHES. THE NAM CONTINUES TO SHOW JUST OVER
3.00 INCHES IN SOME SPOTS...BUT SFC DEW PTS AND CAPE LOOK QUITE A
BIT OVERDONE SO WILL GO WITH OTHER MODELS. STRONG SLY WINDS OVER FAR
ERN UPPER MI WILL QUICKLY DIMINISH AS THE FRONT MOVES E (SEE SHORT
TERM DISCUSSION FOR MORE DETAILS)...BUT WILL GIVE WAY TO GUSTY NW
WINDS OVER AND ALONG CENTRAL AND ERN LAKE SUPERIOR MON NIGHT.

THINK PREVIOUS SHIFT WAS ON TRACK WITH LAGGING CLEARING ON TUE AS
CLOUDS TYPICALLY HANG ON LONGER THAN SHOWN BY MODELS. DO NOT EXPECT
DRIZZLE AS LOW LEVEL MOISTURE LOOKS TOO LIMITED...BUT COULD SEE FOG
NEAR FAR ERN LAKE SUPERIOR. TUE WILL BE QUITE A BIT COOLER AS 850MB
TEMPS FALL TO AROUND 5C...DOWN FROM AROUND 18C MON. IT WILL BE
BREEZY WITH HIGHS IN THE 50S ALONG LAKE SUPERIOR TO THE LOW 70S FAR
SOUTH CENTRAL...AND IN THE 60S IN BETWEEN.

EXPECT GRADUAL WARMING THROUGH AT LEAST THE REST OF THE WORK WEEK.
NO PRECIP EXPECTED WED AND THU AND ONLY LOW END SLIGHT CHANCES OF
PRECIP FRI. PRECIP CHANCES INCREASE SOME FOR THE WEEKEND...WITH
PRECIP AND TEMPS FAIRLY UNCERTAIN AS A FRONTAL BOUNDARY MAY MOVE
INTO THE REGION.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 150 PM EDT SUN JUL 5 2015

EXPECT VFR CONDITIONS TO PREVAIL AT LEAST THROUGH THIS EVENING AT
KIWD/KCMX/KSAW. WITH PRES GRADIENT TIGHTENING BTWN DEPARTING HIGH
PRES AND A COLD FRONT MOVING ACROSS THE NRN PLAINS...WINDS HAVE BECOME
GUSTY THIS AFTERNOON TO AROUND 20KT AT KIWD/KSAW. AS THE COLD FRONT
MOVES CLOSER TONIGHT...SHRA/TSRA WILL APPROACH WRN UPPER MI. IT`S
POSSIBLE SHRA COULD ARRIVE THIS EVENING...BUT BETTER CHC WILL BE LATE
TONIGHT. INCLUDED -SHRA MENTION AT KIWD LATE...BUT ONLY VCSH AT KCMX.
EXPECT CONDITIONS TO LOWER TO MVFR...AND POSSIBLY IFR...AT BOTH KIWD
AND KCMX BY LATE MON MORNING IN SHRA. WITH UNCERTAINTY IN TS
COVERAGE...THUNDER WAS NOT INCLUDED IN FCST. OTHERWISE...INCREASING
WINDS ABOVE NOCTURNAL INVERSION SHOULD LEAD TO LLWS AT ALL TERMINALS
TONIGHT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 337 PM EDT SUN JUL 5 2015

SOUTHERLY WINDS WILL BE ON THE INCREASE ACROSS LAKE SUPERIOR TONIGHT
AS A STRONG COLD FRONT APPROACHES. S TO SE WINDS AHEAD OF THE FRONT
WILL GUST UP TO AROUND 20KT LATE IN THE AFTN OVER THE E HALF OF THE
LAKE. WINDS WILL BE LIGHTER OVER WRN LAKE SUPERIOR AND OVER THE FAR
W...NE WINDS MAY HOLD THRU TONIGHT. WHILE STABILITY OVER THE WATER
WILL LIMIT WINDS CLOSER TO THE WATER SFC...GUSTS TO AROUND 30KT WILL
OCCUR AT THE HIGHEST OBS PLATFORMS OVER THE E HALF OF THE LAKE
TONIGHT/MON...PERHAPS EVEN REACHING GALE FORCE. THE STRONG COLD
FRONT WILL MOVE ACROSS LAKE SUPERIOR MON AND MON EVENING...BRINGING
A WIND SHIFT TO THE N TO NW AT 15-25KT. GIVEN THE UNUSUAL STRENGTH
OF THE FRONT FOR JULY...THERE MAY BE A PERIOD OF WIND GUSTS TO 30KT
AND PERHAPS EVEN GALE FORCE FOR A BRIEF TIME IMMEDIATELY AFTER THE
FRONT PASSES. GALE FORCE GUSTS ARE MOST LIKELY TO OCCUR ROUGHLY IN
THE AREA FROM THE TIP OF THE KEWEENAW ESE TOWARD GRAND MARAIS. WINDS
WILL DIMINISH LATER MON NIGHT THRU TUE AND WILL BECOME LIGHT TUE
NIGHT THRU THU AS HIGH PRES BUILDS OVER THE UPPER GREAT LAKES AND
THEN SLOWLY SHIFTS E.

AS FOR FOG...INCREASING SE TO S WINDS SHOULD PUSH MUCH OF THE FOG OR
AT LEAST THICKER FOG TO THE N PORTION OF THE LAKE TONIGHT. ARRIVAL
OF MORE SHRA/TSTMS TONIGHT/MON WILL LIKELY RESULT IN EXPANSION OF
FOG. FOG WILL THEN BE SCOURED OFF THE LAKE FROM NW TO SE MON
NIGHT/TUE MORNING AS DRIER AIR SPREADS INTO THE AREA BEHIND THE
PASSING COLD FRONT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS


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