000
FXUS63 KMQT 181149
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
749 AM EDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SAT MAY 18 2013

IN THE LARGE SCALE...TROUGH OVER THE ROCKIES WILL SLIDE ONTO THE
HIGH PLAINS BY SUNDAY MORNING ALLOWING RIDGING TO SLIGHTLY BUILD
OVER THE WESTERN GREAT LAKES. ALTHOUGH SFC-H85 TROUGHING OVER THE
DAKOTAS DOES NOT MOVE MUCH TO THE EAST...IT IS ENOUGH TO INCREASE
LOW-LEVEL SOUTHERLY FLOW ACROSS THE UPPER GREAT LAKES. PATTERN IS
SERVING TO INCREASE MOISTURE /PWATS 1.15 OF 1.31 INCHES AT GRB AND
MPX OR AROUND 200 PCT OF NORMAL/ IN WAKE OF DRY SFC HIGH THAT HAS
BEEN ESTABLISHED OVER THE AREA FOR MOST OF THIS WEEK. REGIONAL RADAR
SHOWS DECAYING ECHOES OVER NORTHERN WISCONSIN. MUCH MORE ORGANIZED
AREA OF SHRA/TSRA HAVE DEVELOPED SINCE 03Z FROM CENTRAL MINNESOTA
INTO WEST CENTRAL WISCONSIN ALONG H85 WARM FRONT/GRADIENT OF H85
THETA-E. ADDITIONAL AREA OF SHRA/TSRA SPREADING ACROSS NORTHEAST
SOUTH DAKOTA INTO SOUTHEAST NORTH DAKOTA NEAR CONVECTIVE INDUCED
SHORTAVE/H7-H3 DIFFERENTIAL PVA AND CLOSE TO H7 MOISTURE TRANSPORT.
JUST RECENTLY ANOTHER LARGE CLUSTER OF SHRA/TSRA HAVE FORMED IN THE
WARM AIR ADVECTION REGIME BTWN THESE TWO INITIAL AREAS OF PRECIP.

GIVEN EXTENT OF SHRA/TSRA UPSTREAM OF CWA THIS MORNING AND SINCE
H85-H7 MOISTURE ADVECTION IS FORECAST WEST TO EAST ACROSS CWA
THROUGH THE DAY...INCREASED POPS FOR MOST OF THE WEST AND NORTHERN
CWA AS AT LEAST MULTIPLE REMNANTS OF THIS CONVECTION SHOULD MAKE IT
INTO UPR MICHIGAN. LEANED ON THE NCEP WRF MODELS AND RECENT HRRR AND
EXTRAPOLATION OF LATEST HRRR TO CREATE POPS. RESULT IS LIKELY POPS
MOST OF THE DAY OVER THE WEST HALF...WITH SMALLER CHANCES FARTHER
EAST AS THE RAIN RUNS INTO THE VERY DRY AIRMASS ASSOCIATED WITH SFC
HIGH TO THE EAST. MAJORITY OF TSRA THUS FAR STAYING OVER NORTHERN
MINNESOTA ON GRADIENT OF 1-6KM MUCAPE RESERVOIR. HINT IN MODELS
THAT EASTERN EDGE OF INSTABILITY GRADIENT SLIDES TOWARD WESTERN UPR
MICHIGAN SO HAVE INCLUDED SLIGHT CHANCES FOR TSRA. CONVECTION IS
ELEVATED AND MID-LEVEL LAPSE RATES BARELY GET ABOVE 6C/KM. MAIN
ISSUE WILL BE HEAVY DOWNPOURS AND LIGHTNING STRIKES. TEMPS TODAY
A BIT TOUGH TO FIGURE OUT. EAST GRADIENT WINDS SHOULD KEEP KEWEENAW
CHILLY WITH READINGS STAYING BLO 50 DEGREES. MIXING TO H9 IS PROBABLY
IT WHERE CLOUDS/RAIN PERSIST MOST OF THE DAY. THIS SUPPORTS MAJORITY
OF CWA SEEING HIGHS IN THE 60S...EVENTUALLY...ONCE THE STEADIER RAIN
TAPERS OFF THIS AFTN. SFC WARM FRONT MAY TRY TO POKE INTO FAR SW CWA
LATE IN THE DAY. IF THIS OCCURS AND PRECIP TAPERS OFF/ENDS...THEN
THERE IS POTENTIAL FOR HIGHS TO PUSH WELL INTO THE 70S FROM IWD TO
IMT.

H85 FRONT LIFTS NORTH OF MOST CWA THIS EVENING. KEWEENAW STILL CLOSE
ENOUGH TO FRONT AND WITHIN THE RIBBON OF PERSISTENT MOISTURE
ADVECTION SO KEPT SHRA/ISOLD TSRA THERE THROUGH THE EVENING. DRYING
TREND TAKES HOLD OVERNIGHT AS THE FOCUS FOR SHRA/TSRA...H85 WARM
FRONT AND THETA-E GRADIENT...LIFTS WELL TO NORTH OF UPR MICHIGAN.
KEPT SMALL POPS IN AT ISLE ROYALE LATE TONIGHT THOUGH. TEMPS MOSTLY
IN THE 40S EAST WITH FLOW OFF LK MICHIGAN. LESS MODIFIED AIR FARTHER
WEST ALLOWS MINS TO ONLY FALL INTO THE LOW-MID 50S ALONG LK SUPERIOR
AROUND IWD TO ONTONAGON AND EAST TO BARAGA/L`ANSE AND MARQUETTE
AREAS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 510 AM EDT SAT MAY 18 2013

NAM SHOWS THE 500 MB RIDGE OVER THE EASTERN U.S. 12Z SUN WITH
TROUGHING IN THE ROCKIES. THE TROUGH MOVES EAST ON SUNDAY AND PUSHES
THE RIDGE INTO THE LOWER GREAT LAKES 12Z MON WHERE THE MOVEMENT
EASTWARD STOPS THROUGH 12Z TUE. NAM HAS SOME DEEPER MOISTURE AND
850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA 12Z SUN ONWARD. GFS
SHOWS ABOUT THE SAME THING AS WELL.

THIS PERIOD LOOKS PRETTY WET STARTING WITH SUN AFTERNOON THROUGH MON
NIGHT. WITH SLOW MOVEMENT OF SYSTEM INTO AND THROUGH THE AREA AND
ALSO A WARM FRONT NEAR AND TO THE SOUTH OF THE AREA...THIS SETS UP
THE CWA FOR A WIDESPREAD AND LONG LIVED RAIN EVENT WITH SOME HEAVY
RAIN POSSIBLE. AM FORECASTING ANYWHERE FROM .67 INCH OF QPF OVER THE
SOUTH...TO 1.15 INCHES OVER THE EAST TO OVER 2 INCHES OF RAIN IN THE
FAR WEST NEAR IRONWOOD FROM SUNDAY AFTERNOON THROUGH MONDAY NIGHT
AND THIS DOES NOT SEEM UNREASONABLE WITH PLENTY OF MOISTURE TO THE
SOUTH OF THE AREA AND SLOW SYSTEM MOVEMENT. FOR THIS REASON...BUMPED
POPS UP A BIT TO LIKELY TO CATEGORICAL FOR MOST OF THE CWA THROUGH
THEN. SHOULD SEE SOME SUNSHINE ON SUNDAY. MADE A FEW ADJUSTMENTS TO
TEMPERATURES BASED ON LAKE BREEZES AND WIND DIRECTIONS AND LOWERED
THEM A BIT NEAR THE GREAT LAKES SHORELINES. OTHER THAN THAT...NO
REAL BIG CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW AND TROUGH
IN THE NORTHERN AND CENTRAL PLAINS 12Z TUE WHICH MOVE LITTLE INTO
12Z WED. BY 12Z THU...THE TROUGH AND LOW GET PUSHED A BIT FURTHER
EAST TO THE UPPER GREAT LAKES REGION. THE TROUGH AND LOW MOVE
THROUGH BY 12Z FRI WITH RIDGING BUILDING INTO THE PLAINS LATE ON
FRI. SYSTEM WILL BE SLOW TO MOVE THROUGH THE AREA...SO A COUPLE OF
DAYS OF WIDESPREAD RAIN ARE NOT OUT OF THE QUESTION ALONG WITH
COOLER TEMPERATURES WITH GRADUAL SOUTHWARD MOVEMENT OF THE SYSTEM
AWAY FROM THE AREA. THU INTO FRI...THINGS START TO DRY OUT WITH A
COLD FRONT WELL SOUTH OF THE AREA. TEMPERATURES SLIP TO SLIGHTLY
BELOW NORMAL THIS PERIOD. POPS WILL BE HIGHEST IN THE SOUTH CLOSER
TO A WARM FRONT.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 747 AM EDT SAT MAY 18 2013

A WARM FNT MOVING IN FM THE SOUTH WILL BRING SOME -SHRA/MVFR
CIGS...MAINLY AT IWD/CMX WHERE LLVL WARM/MOIST ADVCTN WL BE MOST
PRONOUNCED. MOIST UPSLOPE FLOW OFF LK SUPERIOR MAY RESULT IN IFR
CONDITIONS AT CMX THIS AFTN AND EVENING. FOLLOWING THE WARM FROPA
TONIGHT...EXPECT WSHFT TO THE S WITH RETURN TO PREDOMINANT VFR WX.
THE ONLY EXCEPTION WL BE AT CMX...WHERE PERSISTENT UPSLOPE ESE WIND
AND MOISTER LLVL AIR WL RESULT IN LINGERING MVFR CONDITIONS THROUGH
MUCH OF THE NIGHT. &&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS.
&&

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

$$

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