Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 030845
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
445 AM EDT WED JUN 3 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EDT WED JUN 3 2015

THE HIGH PRESSURE RIDGE THAT HAS BEEN LEADING TO SUNNY SKIES OVER
THE LAST FEW DAYS IS SLIDING TO THE EAST THROUGH THE CENTRAL GREAT
LAKES REGION. THIS WILL LEAD TO TODAY BEING THE TRANSITION DAY FROM
THE DRY CONDITIONS TO THE MORE UNSETTLED WEATHER THAT WILL CONTINUE
INTO FRIDAY MORNING. WATER VAPOR IMAGERY LOOP SHOWS THE SHORTWAVE
THAT MOVED THROUGH THE DAKOTAS ON TUESDAY AND LED TO THE DEVELOPMENT
OF THE SHOWERS AND THUNDERSTORMS IS NOW MOVING EAST-NORTHEAST
THROUGH NORTHERN MINNESOTA AND ALONG AND JUST EAST OF A SURFACE
TROUGH STRETCHING FROM A LOW IN EASTERN COLORADO TO HUDSON BAY. THAT
CONVECTION HAS BEEN NEARING WESTERN LAKE SUPERIOR OVER THE LAST HOUR
AND SHOULD SEE AT LEAST SHOWERS CONTINUING EAST OVER THE NORTHWEST
PART OF THE LAKE EARLY THIS MORNING. THESE SHOWERS/THUNDERSTORMS ARE
TIED TO THE SHORTWAVE AND THE NOSE OF THE 850MB WARM AIR
ADVECTION...WITH THE NOSE OF THE 500 J/KG OF MUCAPE MAINLY OVER
NORTHERN MINNESOTA. THE INSTABILITY DROPS OFF FAIRLY QUICKLY TO THE
EAST AND EXPECT THE THUNDER POTENTIAL TO DIMINISH QUICKLY TO THE
EAST TOO...ALTHOUGH THE MID LEVEL LAPSE RATES HAVE BEEN NOSING UP
TOWARDS 6.5-7C/KM OVER THE FAR WESTERN U.P.. MEANWHILE...FARTHER TO
THE SOUTHWEST...AND MCS IS DROPPING SOUTHEAST ACROSS CENTRAL
NEBRASKA AND APPEARS TO BE WEAKENING OVER TH LAST HOUR. BACK TO
UPPER MICHIGAN...PARTS OF THE AREA ARE SEEING SOME MID/HIGH CLOUDS
STREAMING EAST-NORTHEAST AHEAD OF THE MN SHOWERS. WITH A TIGHTENING
PRESSURE GRADIENT BETWEEN THE DEPARTING HIGH AND THE SURFACE TROUGH
TO THE NORTHWEST...THE SOUTHERLY WINDS HAVE KEPT UP THROUGH THE
NIGHT AND HAS AIDED TEMPERATURES IN THE WESTERN U.P. REMAINING IN
THE 50S AND EVEN SOME LOWER 60S AT 4AM. OVER THE EASTERN U.P. WHERE
THE HIGH HAS A GREATER INFLUENCE...LIGHTER WINDS HAVE ALLOWED
TEMPERATURES TO FALL INTO THE LOWER 40S AND EVEN A COUPLE UPPER 30S.
BELOW THE HIGH CLOUDS...LOW LEVEL DRY AIR STILL IN PLACE WITH THE
00Z KGRB SOUNDING SHOWING A PWAT VALUE OF 0.39IN WHILE THE 00Z KMPX
SOUNDING SHOWS THE INCREASING MOISTURE THAT THE AREA WILL SEE OVER
THE NEXT 24HRS (PWAT OF 0.96IN).

THE FORECAST FOR THE SHORT TERM IS TRICKY...AS IT LARGELY DEPENDS ON
SUBTLE WAVES LIFTING OUT OF THE WESTERN CONUS TROUGH AND UPSTREAM
CONVECTION ALONG THE SURFACE TROUGH. ALTHOUGH THE FINER DETAILS ARE
MUDDLED BY THE POTENTIAL UPSTREAM CONVECTION...THE GENERAL IDEA OF
SOME SHOWERS AND MAYBE THUNDERSTORMS AFFECTING THE WESTERN U.P.
LATER TODAY AND INTO TONIGHT SEEMS REASONABLE AS THE SURFACE TROUGH
SLOWLY DROPS ACROSS THE AREA. THE SHOWERS/THUNDERSTORMS IN NORTHERN
MINNESOTA ARE EXPECTED TO SLOWLY WEAKEN AND DIMINISH THROUGH THE
MORNING HOURS AS THE 850MB WARM AIR ADVECTION WEAKENS WHILE SHIFTING
EAST INTO THE UPPER GREAT LAKES REGION. HAVE CONTINUED TO SHOW SOME
SLIGHT/CHANCE POPS OVER NORTHWEST LAKE SUPERIOR AND EDGING INTO THE
WESTERN U.P. THROUGH THE DAY. EXPECT THE REST OF THE AREA TO SEE
INCREASING CLOUDS THROUGH THE DAY...AS THE LOW LEVEL DRY AIR HOLDS
OFF THE PRECIPITATION. WITH SOME FILTERED SUNSHINE...SHOULD SEE
ANOTHER DAY WITH NORMAL TO ABOVE NORMAL HIGHS AND HAVE VALUES IN THE
70S FOR ALL BUT THE IMMEDIATE LAKE MICHIGAN SHORELINE. IT WILL GET A
LITTLE GUSTY OVER THE EAST TODAY...WITH A DEEPER MIXING. HAVE GUSTS
TO 20KTS MAINLY FROM KSAW/KIMT EASTWARD AND COULD EVEN SEE SOME
OCCASIONAL HIGHER GUSTS TOWARDS KP53/KERY.

FOR LATER THIS AFTERNOON AND INTO TONIGHT...A LOT OF THE FORECAST
DEPENDS ON THE CONVECTION UPSTREAM IN CENTRAL/SOUTHERN MINNESOTA AND
HOW THAT EVOLVES AS THE SURFACE TROUGH DROPS ACROSS THE AREA.
UNFORTUNATELY WITH THE LIMITED FORCING AND VARYING SOLUTIONS ON WEAK
SHORTWAVES PULLING OUT OF THE WESTERN TROUGH...LEADS TO LOW
CONFIDENCE ON THE SECOND HALF OF THE SHORT TERM FORECAST. WILL
FOLLOW THE IDEA THAT THE LOW LEVEL SOUTHWESTERLY FLOW AND THE
SURFACE TROUGH DROPPING ACROSS THE AREA WILL LEAD TO SCATTERED
SHOWERS MOVING THROUGH THE AREA TONIGHT. HAVE THE HIGHEST POPS OVER
THE WESTERN HALF OF THE CWA...CLOSER TO THE TROUGH AXIS. WITH THE
NOSE OF THE MUCAPE VALUES OVER 250 J/KG MOVING INTO THE WESTERN U.P.
WILL HAVE THE HIGHEST THUNDER CHANCES IN THAT AREA AND THEN DIMINISH
THEM NORTH AND EAST. WITH LIMITED INSTABILITY AND SHEAR...WOULD NOT
EXPECT ANY SEVERE THUNDERSTORMS...BUT IF THEY CAN MOVE INTO THE
WESTERN U.P. ALONG THE WISCONSIN BORDER...COULD SEE SOME BRIEF HEAVY
RAIN.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 304 PM EDT TUE JUN 2 2015

THE WEAKENING SFC LOW NEARING FROM MN WILL BE OVER S ONTARIO AND E
MN AT 00Z THURSDAY...AVERAGING 29.8 INCHES. EXPECT THE LOW TO SLOWLY
SINK SE ACROSS LAKE SUPERIOR AND CENTRAL UPPER MI OVERNIGHT WHILE
FILLING TO A 30.0 INCH TROUGH. AT THIS POINT...EXPECT THE
ASSOCIATED SHORTWAVE TO TRACK ACROSS WI AND S UPPER MI...AND ONLY S-
SW 5-15KT WINDS UP THROUGH 850MB /LIMITING STORM MOTION/. PW VALUES
WILL AVERAGE 1.5IN W AND CENTRAL. PRECIP AMOUNTS ARE ALL OVER THE
PLACE IN THIS CONVECTIVE REGIME...MAKING THE FCST A BIT MORE
DIFFICULT. STILL...CAPE VALUES DON/T REALLY GET MUCH ABOVE 300 J/KG
OVER THE W THIRD OF UPPER MI. WILL HIGHLIGHT NEAR THE WI BORDER AND
S FOR HIGHEST POPS/QPF. THIS TREND WILL CONTINUE INTO THURSDAY...AS
THE SFC TROUGH LEANS FARTHER INTO E UPPER MI...BRINGING LIGHT
ONSHORE FLOW OFF LAKE SUPERIOR...AS LARGE HIGH PRESSURE NEARS FROM
CENTRAL CANADA.

EXPECT THE CANADIAN HIGH TO DROP ACROSS ONTARIO AND INTO LAKE
SUPERIOR/UPPER MI FRIDAY INTO SATURDAY...BEFORE EXITING E SATURDAY
NIGHT. THE RESULT WILL BE ANOTHER ROUND OF COOLER/DRY WX FOR AT
LEAST PART OF FRIDAY INTO SATURDAY NIGHT. HIGHS IN THE 60S WILL BE
COMMON FRIDAY THROUGH SUNDAY...ESPECIALLY AWAY FROM THE WI BORDER.

THERE SEEMS TO BE ENOUGH DISCREPANCIES FROM SUNDAY ON TO RESULT IN A
LOWER CONFIDENCE FCST.  WHILE THE MAIN 500MB LOW/TROUGH WILL BE OVER
FAR E CANADA/NE STATES...THE NEXT TROUGH WILL BE NEARING FROM S
CENTRAL CANADA AND THE N PLAINS ON SATURDAY. THE 02/00Z ECMWF IS
STRONGER IN DEEPENING THE TROUGH ACROSS THE UPPER GREAT LAKES SUNDAY
NIGHT. EITHER WAY IT LOOKS LIKE WET WEATHER WILL MAKE A RETURN FOR
SUNDAY MORNING OR SUNDAY AFTERNOON /QUICKER OFF THE ECMWF/...WITH A
SECOND ROUND MONDAY NIGHT AS NW LINGERS BEHIND THE 500MB TROUGH
SINKING ACROSS THE E THIRD OF THE NATION. SPECIFICS LIKE
TEMPERATURES AND SFC WINDS GET A BIT MESSY...WITH LOWER CONFIDENCE.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 122 AM EDT WED JUN 3 2015

ALTHOUGH HIGH PRESSURE IS DEPARTING...LOW-LEVEL DRY AIR WILL LINGER
...RESULTING IN CONTINUED VFR CONDITIONS AT KIWD/KCMX/KSAW THROUGH
WED MORNING. INCREASING WINDS ABOVE NOCTURNAL INVERSION WILL LEAD TO
LLWS TONIGHT. SHOWERS MOVING INTO WRN UPPER MI WED AFTERNOON ARE
EXPECTED TO DROP CIGS NEAR OR JUST ABOVE MVFR RANGE AT IWD AND CMX
IN THE AFTERNOON AND AT SAW WED EVENING. THERE IS ALSO A POTENTIAL
FOR ISOLD TSRA BUT THE PROBABILITY IS TOO LOW TO INCLUDE MENTION IN
THE TAFS AT THIS TIME.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 AM EDT WED JUN 3 2015

SOUTH TO SOUTHWEST WINDS WILL AFFECT CENTRAL/EASTERN LAKE SUPERIOR
TODAY...AS THE AREA IS BETWEEN A DEPARTING HIGH AND A TROUGH RUNNING
FROM THE DAKOTAS TO HUDSON BAY. WITH THE COLDER LAKE SUPERIOR WATER
TEMPERATURES...EXPECT THE MARINE LAYER TO KEEP THE WINDS IN THE
10-20KT RANGE...ALTHOUGH HIGHER PLATFORMS CLOSER TO THE SOUTHERN
SHORE OF LAKE SUPERIOR MAY SEE GUSTS TO 25-30KTS THROUGH MID
DAY. AS THE SURFACE TROUGH SLOWLY DRIFTS SOUTHEAST ACROSS LAKE
SUPERIOR TONIGHT...EXPECT THE WINDS TO DIMINISH BELOW 15KTS. THE
TROUGH WILL CONTINUE TO SAG SOUTHEAST THURSDAY INTO THURSDAY
NIGHT...LEADING TO NORTHEAST WINDS INCREASING TO 15-20KTS AHEAD
OF AN APPROACHING HIGH IN CENTRAL CANADA. THIS HIGH WILL STRETCH A
RIDGE OVER THE UPPER GREAT LAKES FRIDAY AND SATURDAY AS IT MOVES
INTO SOUTHERN QUEBEC.

FINALLY...WITH SOME RAIN EXPECTED OVER WESTERN LAKE SUPERIOR AND
INCREASING DEWPOINTS...THERE IS THE POTENTIAL FOR FOG OVER THE
WESTERN HALF OF LAKE SUPERIOR LATER TODAY INTO THURSDAY. CONFIDENCE
IS LOW IN THE LOCATION AND THICKNESS...SO WILL JUST HAVE
PATCHY/AREAS OF FOG IN THE FORECAST.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KF
AVIATION...JLB
MARINE...SRF



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