Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 180727
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
327 AM EDT MON AUG 18 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALF BTWN
A SLOWLY RETREATING...DEEP UPR TROF IN QUEBEC AND AN UPR RDG IN THE
PLAINS/UPR MS RIVER VALLEY. SFC HI PRES UNDER THIS RDG AXIS IS
LOCATED JUST NNW OF LK SUP. THE LLVL NE FLOW ON THE SRN FLANK OF
THIS HI IS FUNNELING SOME COOL...MOIST AIR INTO THE UPR LKS BLO
SHARP SUBSIDENCE INVRN ARND H85 AS SHOWN ON THE LOCAL 12Z RAOBS. THE
RESULT HAS BEEN A GOOD DEAL OF LO CLD COVER. THERE WAS EVEN SOME
DRIZZLE INTO THE EARLY AFTN OVER THE HIER TERRAIN OF THE NCENTRAL...
WHERE THE NE WIND PRESENTS A SHARPER UPSLOPE COMPONENT. BUT WITH
DAYTIME HEATING UNDER THE MID LVL DRY AIR AND SOME DRY H95-9
ADVECTION FM THE NE...THE LO CLDS ARE SHOWING SIGNS OF BREAKING
UP...ESPECIALLY IN AREAS THAT EXPERIENCE DOWNSLOPE FLOW. LOOKING TO
THE W...A VIGOROUS SHRTWV IN SRN SASKATCHEWAN IS MOVING EWD JUST N
OF THE CNDN BORDER AND TENDING TO SUPPRESS THE UPR RDG IN THE
PLAINS. THERE IS ANOTHER WEAKER SHRTWV AHEAD OF THIS FEATURE MOVING
THRU MN. CLDS ALONG WITH SHOWERS/A FEW TS ASSOCIATED WITH THIS
DISTURBANCE/OVERALL H85 THETA E ADVCTN IN THE LARGER SCALE SW FLOW
AHEAD OF THE STRONGER SASKATCHEWAN SHRTWV ARE APRCHG DULUTH EARLY
THIS AFTN.

MAIN FCST CONCERNS INTO THIS EVNG ARE FOCUSED ON LO CLD TRENDS.
TIMING/COVERAGE OF SHOWERS ASSOCIATED WITH PAIR OF UPSTREAM SHRTWVS
ARE THE CONCERNS FOR LATER TNGT AND MON.

LATE TODAY/TNGT...ALTHOUGH THE COMBINATION OF SOME LLVL DRY ADVCTN
AND DAYTIME HEATING MAY BREAK UP THE LO CLDS NOW IMPACTING THE CWA
THRU THIS AFTN...FAIRLY HI INVRN BASE OBSVD ON THE 12Z RAOBS WL
PROBABLY MAINTAIN BKN LO CLDS AT MANY LOCATIONS NOT IMPACTED BY
DOWNSLOPING FLOW AS THE SLOWLY RISING LCL WL REMAIN UNDER THE HIER
INVRN BASE. BUT THE LATEST TRENDS INDICATE THESE CLDS SHOULD BE
ALMOST COMPLETELY GONE BY 00Z. AFTER THIS EVNG...CLD COVER/SCT
SHOWERS NOW APRCHG DLH ARE LIKELY TO SPREAD INTO THE WRN CWA IN
ADVANCE OF LEAD SHRTWV AND WHERE STRONGER H85 THETA E ADVCTN WL
DVLP. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR E WHERE THERE IS
LIKELY TO BE A LONGER PERIOD OF MOCLR SKIES/LGT WINDS CLOSER TO SFC
HI MOVING FM ERN LK SUP INTO ADJOINING ONTARIO. ADDED SOME PATCHY
FOG TO THE FCST IN THIS AREA WHERE TEMPS ARE EXPECTED TO FALL BLO
THE CROSS OVER DEWPTS OBSVD THIS AFTN.

MON...MAIN SHRTWV NOW MOVING THRU SRN SASKATCHEWAN IS FCST TO MOVE
INTO MN DURING THE AFTN. ALTHOUGH SOME SCT SHOWERS ASSOCIATED WITH
THE LEAD DISTURBANCE/AREA OF H85 THETA E ADVCTN MAY SPREAD INTO THE
CENTRAL AND ERN CWA...THESE ARE MORE LIKELY TO WEAKEN WITH TIME AS
THE CLUSTER MOVES TOWARD THE SHRTWV RDG AXIS/DRIER MID LVL AIR ON
THE WRN FLANK OF THE SLOW MOVING QUEBEC TROF. MORE NMRS SHOWERS ARE
LIKELY TO MOVE INTO THE W HALF OF THE CWA IN THE AFTN UPON THE
ARRIVAL OF DEEPER MSTR/MORE VIGOROUS DYANMIC SUPPORT ASSOCIATED WITH
THE MORE VIGOROUS TRAILING SHRTWV IN THE PRESENCE OF DAYTIME
HEATING. WITH FCST MUCAPES NO HIER THAN 100-200 J/KG ASSOCIATED WITH
A GOOD DEAL OF CLD COVER/EXPECTED DAYTIME HI TEMPS MAINLY IN THE
60S...WL LEAVE OUT A MENTION OF TS EXCEPT OVER THE FAR W...WHERE THE
MORE UNSTABLE GFS HINTS MUCAPES MAY REACH 500 J/KG CLOSER TO THE
INCOMING DISTURBANCE/COLDER AIR ALF.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM EDT MON AUG 18 2014

THE START OF THE PERIOD WILL BE A WET ONE AS AN UPPER WAVE OVER WRN
LAKE SUPERIOR AT 12Z TUE CLOSES OFF AS IT MOVES INTO THE WRN U.P. BY
18Z TUE. THE UPPER LOW WILL THEN SLOW DOWN...FINALLY LEAVING THE
AREA LATER ON WED. THE SFC LOW WILL BE SOMEWHERE OVER NRN WI OR
ALONG THE WI/MI BORDER AT 12Z TUE AND WILL SLOWLY SHIFT E INTO TUE
NIGHT BEFORE MORE QUICKLY MOVING SE ON WED. PWATS ON TUE WILL BE
BETWEEN 1.5 AND 1.7 INCHES /NORMAL IS AROUND AN INCH/...WHICH WHEN
COMBINED WITH THE FORCING FROM THE UPPER LOW/CYCLONIC FLOW AND
UPSLOPE FLOW OFF THE GREAT LAKES IN SPOTS /ESPECIALLY OVER WRN UPPER
MI/...WILL RESULT IN DECENT PRECIPITATION PRODUCTION. THINK THAT
SOME SPOTS COULD SEE EASILY OVER AN INCH OF PRECIP ON TUE/EARLY TUE
NIGHT...DEPENDING ON SMALLER SCALE FEATURES THAT ARE NOT ENTIRELY
CLEAR AT THIS POINT. WHILE IT IS HARD TO GET TOO SPECIFIC ON
HEAVIEST PRECIP PLACEMENT/TIMING...THINK THAT MOST OF THE CWA WILL
SEE PERIODS OF RAIN TUE INTO TUE NIGHT...SO WILL INCREASE POPS TO
LIKELY IN MOST PLACES. WILL LEAVE THUNDER CHANCES TO A MINIMUM...BUT
WILL HAVE A CHANCE OF THUNDER OVER SCENTRAL AND WRN UPPER MI WHERE
CAPES WILL BE A BIT HIGHER AT AROUND 200J/KG DURING THE DAY TUE.
WITH THICK CLOUD COVER...MAX TEMPS ON TUE WILL BE IN THE MID 60S TO
LOW 70S...OR 5 TO POSSIBLY 10 DEGREES BELOW NORMAL.

WED WILL SEE DECREASING PRECIP CHANCES AS THE SYSTEM MOVES SE...BUT
DO LINGER CHANCE POPS THROUGH THE MORNING. BEHIND THE SYSTEM...AN
UPPER RIDGE DEVELOPS OVER THE REGION...WHICH WILL KEEP THINGS A BIT
DRIER THAN EARLY IN THE WEEK. MODELS DO POINT TO PRECIPITATION
OCCURRING ALONG A WARM FRONT THAT MOVES THROUGH THU INTO THU
NIGHT...BUT IT IS UNCERTAIN HOW MUCH PRECIP WILL MAKE IT INTO THE
CWA AS THE FRONT MOVES UNDER THE UPPER RIDGE AND INTO THE DRIER AIR.
WILL HAVE CHANCE POPS THU INTO THU NIGHT...AND SOME LINGERING POPS
INTO FRI.

UNCERTAINTY IS GREATER GOING INTO THE WEEKEND AS MODELS SHOW QUITE A
BIT OF VARIABILITY /RUN TO RUN AND MODEL TO MODEL/ WITH THE
STRENGTH/TRACK/TIMING OF A LOW PRESSURE SYSTEM MOVING SOMEWHERE IN
OR NEAR THE REGION. WHILE MODELS DO APPEAR TO AGREE WITH QPF ON
SAT/SAT NIGHT...THEY DO NOT AGREE ON THE REASON FOR THAT QPF...SO
CONFIDENCE IS LOWER THAN IT WOULD SEEM BY JUST LOOKING AT QPF.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 126 AM EDT MON AUG 18 2014

CHALLENGING FCST SHAPING UP OVER THE NEXT 24HRS AS WEAK DISTURBANCES
MOVE INTO THE UPPER GREAT LAKES. WHILE VFR CONDITIONS SHOULD PREVAIL
OVERNIGHT AT KCMX/KSAW...LIGHT UPSLOPE FLOW AT BOTH TERMINALS MAY
LEAD TO LOW MVFR OR IFR CIGS AT TIMES. SCT SHRA SPREADING THRU NE
MN/NW WI SHOULD AFFECT KIWD OVERNIGHT AND KCMX TOWARD DAYBREAK...
BRINGING MVFR CONDITIONS WITH THE POTENTIAL FOR IFR. ALL TERMINALS
SHOULD GENERALLY BE MVFR FOR MUCH OF THE DAY WITH SHRA SCATTERED
AROUND THE AREA. INCREASINGLY MOIST LOW-LEVELS AND LIGHT UPSLOPE
FLOW SHOULD LEAD TO IFR CONDITIONS DEVELOPING THIS EVENING AT
KCMX/KSAW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 17 2014

EXCEPT FOR A BRIEF PERIOD OVER EASTERN LAKE SUPERIOR LATE MON NIGHT
INTO TUE WHEN WINDS MAY REACH 20-25 KTS UNDER A SHARPER PRES
GRADIENT BETWEEN HI PRES IN QUEBEC AND A LO TRACKING THRU THE UPPER
MIDWEST...EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE
THE CHILLY WATERS OF LAKE SUPERIOR.
&&

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

$$

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







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