Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 271136
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
736 AM EDT WED MAY 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM EDT WED MAY 27 2015

A SHORTWAVE AND ASSOCIATED SFC LOW ARE DRIVING RAIN SHOWERS OVER
MAINLY WESTERN AND CENTRAL UPPER MI EARLY THIS MORNING. THIS AXIS OF
GREATEST PRECIP AMOUNTS/COVERAGE WILL SHIFT E OVER PRIMARILY THE ERN
U.P. THIS MORNING AND WILL EXIT E OF THE CWA BY 21Z TODAY.

MEANWHILE...A WEAKER SHORTWAVE CURRENTLY OVER SRN SASKATCHEWAN MOVE
ACROSS WRN AND CENTRAL UPPER MI LATE THIS AFTERNOON INTO THIS
EVENING. THE GREATEST FORECAST UNCERTAINTY IN THE SHORT TERM IS
RELATED TO CONVECTIVE POTENTIAL WITH THIS SECOND SHORTWAVE.
CONVECTIVE POTENTIAL WILL RELY HEAVILY ON HOW FAST PRECIP AND CLOUD
COVER MOVE OUT TODAY...DETERMINING INSTABILITY LEVELS. ALSO IN
QUESTION IS THE EXACT TRACK OF THE SHORTWAVE...WHICH IS SHOWN
HEADING S OF THE CWA BY A COUPLE MODELS. AT THIS POINT...IT APPEARS
THERE WILL BE CONVECTION FIRING ALONG THE LAKE BREEZE BOUNDARIES
OVER NCENTRAL UPPER MI LATE THIS AFTERNOON AND THIS EVENING AND
POSSIBLY ALONG THE WI BORDER AS WELL. AS FOR STRENGTH OF THE
CONVECTION...CONFIDENCE IS QUITE LOW. MODELS RANGE FROM A FEW
HUNDRED J/KG OF CAPE TO 1500 J/KG. ALSO...MODELS INDICATE THAT
EFFECTIVE SHEAR WILL INCREASE FROM VERY MARGINAL LEVELS EARLY TODAY
TO 30-35KTS AROUND EXPECTED TIME OF CONVECTIVE INITIATION (21Z) AS
THE SHORTWAVE MOVES INTO THE AREA. ADDITIONALLY...WNW FLOW IS THE
FAVORED FLOW FOR STRONGER CONVECTION OVER THE NCENTRAL. CERTAINLY A
CONDITIONAL AND VERY UNCERTAIN STRONG/SEVERE THREAT. WILL NOT HYPE
THE THREAT UP MUCH RIGHT NOW...ESPECIALLY GIVEN THAT IT WILL BE
FAIRLY LATE IN THE DAY...MORE INTO THE EVENING TIME FRAME...SO THE
DAY SHIFT WILL HAVE PLENTY OF TIME TO MONITOR TRENDS AND MAKE
REFINEMENTS. OTHERWISE...EXPECT HIGH TEMPS TODAY IN THE 60S E HALF
TO 70S W HALF...LOCALLY COOLER NEAR LAKE SUPERIOR.

REMAINING CONVECTION (IF ANY) WILL DISSIPATE TONIGHT AS THE
SHORTWAVE MOVES OUT AND INSTABILITY DIMINISHES. SKIES WILL BE
CLEARING INITIALLY...BUT CLOUDS WILL DEVELOP NEAR LAKE SUPERIOR AS
FLOW BECOMES NELY LATER IN THE NIGHT. LOWS WILL MAINLY BE IN THE
40S...WITH LOWS AROUND 50 OVER THE SCENTRAL.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM EDT WED MAY 27 2015

NAM SHOWS A 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z THU. THIS
TROUGH MOVES INTO THE NORTHERN PLAINS 12Z FRI AND THIS WILL AFFECT
THE AREA FRI AND FRI NIGHT. NAM BRINGS IN SOME 850-500 MB Q-VECTOR
CONVERGENCE AND DEEPER MOISTURE THU NIGHT THROUGH FRI NIGHT.

HAVE THU MORNING DRY BEFORE LAKE BREEZE CONVECTION BREAKS OUT IN THE
AFTERNOON WITH LAKE BREEZE CONVERGENCE IN THE WEST HALF OF THE U.P.
KEPT IN CHANCE POPS IN THE WEST LATE THU NIGHT. THE BEST CHANCE FOR
PCPN WILL BE FRI AND WENT CATEGORICAL POPS IN THE AFTERNOON FOR MOST
OF THE CWA AND THEN HAVE POPS ONLY IN THE SOUTHERN AND EASTERN CWA
LATE FRI NIGHT. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES OR WEATHER. THIS SYSTEM COULD PUT OUT ANOTHER INCH OF
QPF FOR THU NIGHT THROUGH FRI NIGHT ACROSS THE AREA AND LOOKS TO BE
THE LAST HEAVY RAIN SYSTEM FOR THIS FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER CENTRAL
CANADA 12Z SAT WITH A COLD AIRMASS OVER THE AREA. A SFC FRONT IS
WELL TO THE SOUTH ON SAT WITH SFC HIGH PRESSURE BUILDING IN. THE
UPPER PATTERN THEN GOES ZONAL OVER THE UPPER GREAT LAKES 12Z SUN
WITH THE SFC HIGH OVER THE AREA AND REMAINS THAT WAY INTO MON. ON
TUE...THE SFC HIGH IS IN THE CANADIAN MARITIMES AND THE AREA HAS A
WARM FRONT TO THE WEST. TEMPERATURES WILL BEGIN A WARMUP THIS
FORECAST PERIOD BY STARTING BELOW NORMAL AND THEN WARMING TO NEAR
NORMAL. LOOKS DRY FOR MOST OF SAT THROUGH MON AND THEN A SLIGHT
CHANCE OF RAIN COMES BACK INTO THE PICTURE FOR MON NIGHT AND TUE
WITH THE WARM FRONT OFF TO THE WEST. KEPT FROST POSSIBILITY IN FOR
SAT NIGHT AND WILL MENTION IN THE HWO.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 735 AM EDT WED MAY 27 2015

IMPROVEMENT WILL OCCUR FROM W TO E THIS MORNING AND EARLY
AFTERNOON...AND IS ALREADY STARTING AT KIWD. EXPECT TO SEE RAIN
SHOWERS AND POSSIBLE SOME THUNDER AT KSAW THIS
AFTERNOON/EVENING...AND POSSIBLY AT KIWD BUT HAD LOWER CONFIDENCE SO
ONLY WENT WITH VCSH. OTHERWISE...COULD SEE SOME FOG/LOW CIGS LATE
TONIGHT AT KCMX AND KSAW AS FLOW COMES OFF LAKE SUPERIOR.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 AM EDT WED MAY 27 2015

WINDS ARE EXPECTED TO STAY AT OR BELOW 20 KNOTS FOR MOST OF THIS
FORECAST PERIOD WITH THE EXCEPTION OF FRI NIGHT INTO EARLY SATURDAY
WHERE THEY WILL BE UP TO 25 KNOTS ACROSS EASTERN LAKE SUPERIOR. FOG
WILL LINGER THROUGH INTO TONIGHT AND WILL BE DENSE AT TIMES.
ADDITIONAL FOG IS EXPECTED TO DEVELOP THURSDAY NIGHT AND FRIDAY
AHEAD OF THE NEXT LOW AND ASSOCIATED COLD FRONT.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...07
AVIATION...TITUS
MARINE...TITUS


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