839 
FXUS63 KMQT 210541
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
141 AM EDT SUN JUL 21 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EDT SAT JUL 20 2013

WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NE 
CANADA AND A WEAK RIDGE INTO MANITOBA RESULTING IN CONFLUENT WNW 
FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...A RIDGE EXTENDED FROM 
SRN MANTIOBA INTO NW ONTARIO TO NW LAKE SUPERIOR. ABUNDANT DIRUNAL 
CU HAD DEVELOPED IN THE COOL AIR TO THE NORTH OF LAKE SUPERIOR WHERE 
850 MB TEMPS WERE DOWN TO 2C-3C. FARTHER SOUTH...VIS LOOP SHOWED 
ONLY SCT CU OVER THE W HALF OF UPPER MI.  

TONIGHT...WITH CLEAR SKIES AND LIGHT WINDS TONIGHT...FAVORABLE 
RADIATIONAL COOLING CONDITIONS IN THE DRY AIRMASS OVER THE REGION 
(PWAT BELOW 0.50 INCH)WILL ALLOW TEMPS TO DROP TO NEAR THE LOW END 
OF GUIDANCE...NEAR 40 OVER THE COLDER INLAND LOCATIONS.  

SUN...AS THE SFC HIGH SHIFTS EAST OF THE AREA AND THE MID LEVEL 
FLOW BECOMES MORE ZONAL...SRLY FLOW AND WAA WILL INCREASE AHEAD OF 
APPROACHING SHORTWAVE AND FRONTAL SYSTEM OVER THE NRN PLAINS. TEMPS 
SHOULD CLIMB INTO THE LOWER TO MID 70S INLAND WITH LOWER READINGS IN 
THE MID TO UPPER 60S ALONG THE GREAT LAKES. MODELS SUGGEST THAT THE 
GREATEST INCREASE IN MOISTURE AND STRONGER 300-310K ISENTROPIC LIFT 
WILL REMAIN TO THE SOUTH AND WEST OF UPPER MI FROM SRN MN INTO 
CNTRL WI LATE SUN AFTERNOON. SO...THE FCST MAINTAINS ONLY SLIGHT 
CHANCE POPS INTO THE FAR WEST

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 419 PM EDT SAT JUL 20 2013

UPPER AIR PATTERN THROUGH NEXT WEEK DRIVEN BY TWO AREAS OF LOWER 
HEIGHTS...ONE OVER GULF OF ALASKA/BRITISH COLUMBIA AND THE OTHER
VCNTY OF HUDSON BAY ACROSS QUEBEC. IN BTWN THESE TWO...WNW FLOW 
HOLDS IN PLACE FROM WESTERN CANADA ACROSS GREAT LAKES. MOST 
PERSISTENT RIDGING WILL BE LIMITED TO SOUTHWEST PART OF CONUS.
PATTERN DOES NOT LOOK APPRECIABLY WARM...ESPECIALLY COMPARED TO 
THE RECENT HEAT WAVE THAT AFFECTED GREAT LAKES REGION. OVERALL 
TEMPS THROUGH THE PERIOD WILL BE AT OR SLIGHTLY BLO NORMAL /NORMAL 
HIGH TEMPS ON AVERAGE THIS TIME OF YEAR ARE IN THE UPR 70S NORTH TO 
LOWER 80S SOUTH/. WARMEST DAY MOST LIKELY ON MONDAY AS WARM FRONT 
LIFTS ACROSS UPPER LAKES RESULTING IN SW SFC WINDS. COLD FRONT 
MOVES IN MONDAY NIGHT THOUGH...MAKING THIS STAY IN THE WARM SECTOR 
VERY BRIEF. SHRA/TSRA POSSIBLE AS THESE FRONTAL BOUNDARIES AFFECT 
THE AREA. ONLY OTHER CHANCE OF RAIN ARRIVES LATER THURSDAY INTO 
FRIDAY AS ANOTHER SFC TROUGH CROSSES THE REGION. WEAK HIGH PRESSURE 
AND DRY WEATHER WILL DOMINATE THE WEATHER PATTERN REST OF THE LONG 
TERM.

FIRST FOCUS IN LONGER TERM IS SHORTWAVE PRESSING INTO SCNTRL CANADA 
ON SUNDAY NIGHT AND SFC LOW/TROUGH MOVING ACROSS NORTHERN PLAINS. 
SLIGHT H85 TEMP/MOISTURE ADVECTION OVER UPR MICHIGAN AHEAD OF THE 
WAVE AND SFC TROUGH...BUT INSTABILITY IS PRETTY MINIMAL WITH MUCAPES 
1-6KM A FEW HUNDRED J/KG AT BEST...MAINLY OVER FAR WEST LK SUPERIOR 
CLOSER TO STRONGEST H85-H7 MOISTURE TRANSPORT. FCST SOUNDINGS SHOW 
INCREASE OF H8-H7 MOISTURE BUT HINT AT DRY AIR BLO AND ABOVE THIS 
LAYER. WITH LACK OF INSTABILITY AND DEEP MOISTURE AND LARGER SCALE 
FORCING...THINK COVERAGE TO ANY SHRA/TSRA WILL BE LIMITED SUN NIGHT 
BUT CANNOT COMPLETELY RULE IT OUT. 

SEEMS THAT BETTER CHANCES FOR SHRA/TSRA OCCUR ON MONDAY IN THE 
MORNING DUE TO CLOSER PROXIMITY OF SHORTWAVE/H85 TROUGH AND 
RESULTING SHARPER WARM AIR ADVECTION AND INCREASING H85 MOISTURE 
TRANSPORT. EXPECT THIS WARM AIR ADVECTION SHRA/ISOLD TSRA TO SHIFT 
NORTH BY AFTN ALONG SFC WARM FRONT AND THEN...PROVIDED THERE IS 
ENOUGH CLEARING OF MORNING CLOUDS/SHRA/TSRA...THERE SHOULD BE PERIOD 
OF BUILDING INSTABILITY DURING PEAK HEATING AS TEMPS WARM INTO THE 
UPR 70S/LWR 80S. MLCAPES TOP OUT AROUND 800-1200J/KG...HIGHEST 
ALONG WI BORDER. DEEP LAYER SHEAR INCREASES IN WARM SECTOR OUT 
AHEAD OF COLD FRONT TO 30-40 KTS AS SHORTWAVE CROSSES NORTHERN 
ONTARIO AND ADJACENT LK SUPERIOR. SOUNDINGS SHOW A BIT OF CAPPING 
AROUND H8 AND THIS ADDS UNCERTAINTY TO INITIATION. BASED ON CAPE AND 
SHEAR BALANCE...THERE SEEMS TO BE AT LEAST SMALL POTENTIAL FOR ISOLD 
SVR STORMS. SUPERCELLS POSSIBLE AS WINDS SHOW SUFFICIENT VEERING WITH 
HEIGHT. HAIL/WIND PRIMARY HAZARDS WITH LOWER WBZERO HEIGHTS AROUND 
11KFT AND DCAPE UP TO 1000J/KG. ALL THIS IS CONDITIONAL ON HOW MUCH 
INSTABILITY CAN MATERIALIZE. SINCE SPC DAY 3 DID INDICATE SEE TEXT 
OVER THE AREA...THINK IT IS WORTH AN HWO MENTION.

COLD FRONT BLOWS THROUGH CWA PRETTY QUICKLY MONDAY EVENING/EARLY 
OVERNIGHT. TRENDED TOWARD LOWER POPS 6Z-12Z ON TUESDAY WITH DRYING
NOTED IN SOUNDINGS AND GFS/ECMWF SHOWING LITTLE IF ANY QPF IN THAT 
TIME FRAME THE LAST FEW MODEL RUNS. IN WAKE OF THE COLD FRONT ON 
TUESDAY...COULD END UP WITH NEARLY CARBON COPY OF TODAY...COOL TEMPS 
ALONG LK SUPERIOR/HIGHER SWIM RISK AND READINGS INTO LOWER 70S TOWARD
WI BORDER. CUT GUIDANCE TEMPS FOR TUESDAY NIGHT WITH HIGH CENTER 
OVERHEAD. FAVORED COLD SPOTS OVER MAINLY WEST COULD REACH TO AROUND 
40 DEGREES. STAYS QUIET THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE 
SLOWLY RETREATS. 

NEXT CHANCE OF RAIN RETURNS THURSDAY INTO FRIDAY. MODELS HAVING 
TOUGH TIME HANDLING SHORTWAVE TROUGH PUSHING THROUGH IN WNW FLOW 
ALOFT. LATEST GFS AND ECMWF WOULD INDICATE SHORTWAVE PASSAGE 
THURSDAY OR THURSDAY NIGHT. BLEND OF CONSENSUS SHOWS SLIGHT 
CHANCE/LOW CHANCE POPS AS ANOTHER COLD FRONT CROSSES THE AREA 
TIED TO THE WAVE. SATURDAY LOOKING PRETTY COOL YET AGAIN BEHIND 
THIS COLD FRONT. PROBABLY WILL END UP SIMILAR TO WHAT IS OCCURRING
TODAY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 141 AM EDT SUN JUL 21 2013

VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH 
PRESSURE REMAINS OVER THE REGION.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EDT SAT JUL 20 2013

AS HIGH PRESSURE BUILDS INTO THE NORTHERN GREAT LAKES...WINDS WILL 
DIMINISH THIS EVENING TO LESS THAN 20 KNOTS. SRLY WINDS WILL 
INCREASE TO AROUND 20 KNOTS AHEAD OF A LOW PRESSURE TROUGH MOVING 
THROUGH THE AREA ON MONDAY. NORTH TO NORTHWEST WINDS WILL THEN INCREASE 
TO 20 TO 30 KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND A COLD 
FRONT MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN 
BELOW 20 KNOTS THROUGH THURSDAY.
&&

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

$$

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