Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 271941
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
341 PM EDT SUN JUL 27 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 341 PM EDT SUN JUL 27 2014

THE CLEARING LINE ALONG THE INTERNATIONAL BORDER OF MN AND ACROSS
CENTRAL LAKE SUPERIOR CONTINUES TO SINK S ACROSS THE REGION. EXPECT
MOST IF NOT ALL SHOWERS TO BE OUT OF THE CWA BY 00Z MONDAY. THE SFC
LOW HAS SHIFTED ACROSS LOWER MI...WITH THE 500MB TROUGH TRAILING
ACROSS E UPPER MI THROUGH SE WI. DO NOT EXPECT THE FOG TO STICK
AROUND TOO MUCH LONGER. LITTLE TO NO FOG IS LINGERING BEHIND THE DRY
AIR SHIFTING IN ACROSS LAKE SUPERIOR. PW VALUES THIS AFTERNOON
AROUND 1.15IN /110-125 PERCENT OF NORMAL/ WILL FALL TO AROUND
0.5-0.6IN BY 06Z MONDAY /50-60 PERCENT OF NORMAL/. KEPT WITH THE
LOWER TEMP GUIDANCE STILL FOR TONIGHT...WITH SEVERAL OF OUR
TYPICALLY COOL LOCATIONS FALLING INTO THE LOW TO MID 40S.

THE DRY WEATHER WILL CONTINUE THROUGH THE DAY MONDAY FOR MOST
LOCATIONS AS THE LARGE SFC HIGH STRETCHING ACROSS S CENTRAL CANADA
INTO THE N PLAINS THIS AFTERNOON...EXPANDS IT/S REACH INTO THE UPPER
GREAT LAKES. CAN/T RULE OUT SOME DIURNAL CLOUDS DEVELOPING INLAND
FROM LAKE SUPERIOR FROM LATE MORNING ON. WENT MINIMAL ON THE CLOUDS
FOR NOW...GIVEN THE UNCERTAINTY. THE BEST CHANCE OF ANY SHOWERS WILL
BE OVER W LAKE SUPERIOR AND NEAR ISLE ROYALE DURING THE AFTERNOON
HOURS. THE APPROACHING SHORTWAVE CAN ALREADY BE SEEN PUSHING S OUT
OF W HUDSON BAY. KEPT THE MENTION OF THUNDERSTORMS MAINLY TO THE NW
OF LAKE SUPERIOR...BUT THEY MAY CLIP ISLE ROYALE BY LATE AFTERNOON.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 402 AM EDT SUN JUL 27 2014

A HIGHLY AMPLIFIED FLOW PATTERN WILL BE IN PLACE FOR MUCH OF THE
NEXT WEEK...LEADING TO OCCASIONAL PERIODS OF SHOWERS AND AFTERNOON
THUNDERSTORMS. THE SHORTWAVE CURRENTLY MOVING THROUGH NORTHERN
MINNESOTA WILL LEAD TO THE AMPLIFICATION OF THE UPPER LOW SPINNING
OVER NORTHERN QUEBEC TODAY AND TONIGHT. THIS UPPER LOW CENTER WILL
ROTATE AROUND OR JUST EAST OF THE JAMES BAY AREA THROUGH THIS
UPCOMING WORK WEEK BEFORE FINALLY LIFTING NORTHEAST NEXT WEEKEND.
DETERMINISTIC AND ENSEMBLE MEMBERS/MEANS SHOW STRONG SUPPORT FOR
THIS PATTERN THROUGH THE WEEK (WITH THE UPPER TROUGH AXIS
STRETCHING SOUTH THROUGH THE EASTERN GREAT LAKES AND THE
APPALACHIANS) BEFORE GRADUALLY WEAKENING AND LIFTING NORTH HEADING
INTO THE FIRST WEEK OF AUGUST. WITH THE STRONG RIDGE OVER THE
ROCKIES...THE UPPER GREAT LAKES REGION WILL BE UNDER NORTHWEST FLOW
ALOFT THROUGH THE WEEK. THUS...EXPECT SEVERAL WAVES TO DROP
SOUTHEAST THROUGH THE REGION OVER THIS WEEK...LEADING TO SEVERAL
OPPORTUNITIES FOR SHOWERS AND AFTERNOON/EVENING THUNDERSTORMS.
ALTHOUGH TIMING THESE WAVES IS TRADITIONALLY DIFFICULT IN NORTHWEST
FLOW...THE MODELS SEEM TO HAVE A DECENT AGREEMENT ON THESE SUBTLE
WAVES THROUGH MID WEEK AND LEADS TO GREATER CONFIDENCE ON THE
TIMING. IN ADDITION...850MB TEMPERATURES FOR THE UPCOMING WEEK WILL
BE BETWEEN 4-12C WITH THE COLDEST VALUES ON MONDAY AND THEN A
GRADUAL WARM-UP TO THROUGH THE WEEK. THIS WILL LEAD TO BELOW NORMAL
TEMPERATURES ON MONDAY (HIGHS GENERALLY IN THE MID 60S TO LOWER 70S
AND AROUND 5-10 DEGREES BELOW NORMAL) BEFORE SLOWLY WARMING TOWARDS
NORMAL OR SLIGHTLY BELOW NORMAL VALUES BY NEXT WEEKEND.

MONDAY LOOKS TO BE THE DRIEST DAY...EVEN THOUGH A WEAK SHORTWAVE
ROTATES THROUGH DURING THE MORNING HOURS. THIS DRIER PERIOD WILL BE
SUPPORTED BY DRIER AIR ASSOCIATED WITH THE EASTERN EDGE OF A HIGH
PRESSURE RIDGE FROM A HIGH IN THE DAKOTAS. SOME LINGERING MOISTURE
WILL LIKELY LEAD TO SOME DIURNAL CU AWAY FROM LAKE SUPERIOR AND THE
NORTHERLY FLOW OFF THE LAKE. THE NEXT WEAK WAVE DIVES SOUTHEAST FROM
NORTHWESTERN ONTARIO ON MONDAY NIGHT AND MAY PRODUCE A FEW SHOWERS
OVER THE NORTHWEST HALF/THIRD OF THE CWA. LOSS OF DIURNAL HEATING
LIKELY WON/T HELP THE SHOWERS PUSHING SOUTHEAST OFF THE LAND AND
OVER LAKE SUPERIOR ON MONDAY NIGHT...BUT FEEL CONTINUING SLIGHT
CHANCES FOR RAIN IS REASONABLE.

A MUCH STRONGER SHORTWAVE TROUGH WILL SWEEP ACROSS THE UPPER GREAT
LAKES REGION TUESDAY AND LEAD TO THE BEST OPPORTUNITY FOR WIDESPREAD
SHOWER/THUNDERSTORM ACTIVITY DURING THE UPCOMING WORK WEEK. A WEAK
AREA OF LOW PRESSURE WILL LIKELY DEVELOP WITH THIS WAVE OVER
NORTHERN ONTARIO AND SWEEP A SURFACE TROUGH ACROSS THE AREA TUESDAY
AFTERNOON. BASED ON THE CONSISTENCY IN THE MODELS WITH THIS
FEATURE...WILL TREND POPS UP TO HIGH END CHANCES OVER INLAND AREAS
DUE TO DAYTIME HEATING (AND ESPECIALLY OVER THE CENTRAL/EAST WHERE
THE BEST FORCING FROM THE SHORTWAVE WILL BE LOCATED). MU/ML CAPE
VALUES INCREASE GOING INTO THE AFTERNOON (GENERALLY 250-1000
J/KG)...SO PREVIOUS SHIFT/S IDEA OF STARTING THUNDER CHANCES FOR THE
AFTERNOON HOURS IS REASONABLE. UNIDIRECTIONAL 0-6KM SHEAR OF
20-25KTS AND A FAIRLY TALL/SKINNY CAPE (NCAPE VALUES 0.06-0.1)
SHOULD LIMIT ANY SEVERE WEATHER POTENTIAL. GREATEST CONCERN WOULD BE
BRIEF HEAVY RAIN IN THE STRONGER SHOWERS/THUNDERSTORMS...BUT THE
UNFAVORABLE NORTHWEST FLOW KEEPING PWATS GENERALLY BELOW 1.0 INCH
(SLIGHTLY BELOW NORMAL FOR LATE JULY) SHOULD KEEP AMOUNTS FROM
GETTING MUCH ABOVE 0.5IN.

EXPECT A DRYING TREND THROUGH TUESDAY NIGHT AS THE SHORTWAVE
DEPARTS AND AREA COMES BACK UNDER THE INFLUENCE OF THE WEAK SURFACE
RIDGE. THIS SHOULD CONTINUE THROUGH MUCH OF WEDNESDAY...BUT DIURNAL
HEATING AND AN APPROACHING SHORTWAVE FOR WEDNESDAY NIGHT MAY BE
ENOUGH TO PRODUCE A FEW SHOWERS AND AN ISOLATED THUNDERSTORMS OVER
INTERIOR WEST/CENTRAL LOCATIONS ON WEDNESDAY AFTERNOON. WILL JUST
SHOW SLIGHT CHANCES DURING THE AFTERNOON HOURS FOR THAT POTENTIAL.
THAT NEXT SHORTWAVE WILL LIKELY SWEEP THROUGH WEDNESDAY NIGHT...BUT
LACK OF DIURNAL HEATING AND MORE MARGINAL MID LEVEL MOISTURE LEADS
TO LIMITED CONFIDENCE OF SHOWER POTENTIAL.

CONFIDENCE WANES AFTER WEDNESDAY NIGHT...AS THE BEST UPPER LEVEL
ENERGY BECOMES FOCUSED CLOSER TO THE UPPER LOW NEAR JAMES BAY
THROUGH THE REST OF THE FORECAST PERIOD AND THE WEAK SURFACE RIDGE
CONTINUES TO COVER THE AREA. WILL ATTEMPT TO FOLLOW A GENERAL MODEL
CONSENSUS (SLIGHT AND LOW CHANCE POPS) FOR THE REST OF THE PERIOD
AND TRY TO SHOW SOME TIMING OF DIURNALLY DRIVEN SHOWERS OVER THE
LAND AREAS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 206 PM EDT SUN JUL 27 2014

THE BACK EDGE OF THE IFR CEILINGS WAS LOCATED ACROSS THE
INTERNATIONAL BORDER WITH MN...AND SPLIT ISLE ROYAL IN HALF. LOOK
FOR THE LINE TO CROSS ALL 3 TAF SITES BY AROUND 22Z. THERE ARE SOME
INDICATIONS THAT SCT-BKN MVFR CEILINGS COULD LINGER UNTIL CLOSER TO
00Z MONDAY. OTHERWISE...VFR CEILINGS AND VIS WILL BE THE RULE
OVERNIGHT THROUGH MONDAY AS DRY HIGH PRESSURE SLIDES OVERHEAD.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 341 PM EDT SUN JUL 27 2014

FOG WILL CONTINUE TO QUICKLY END N TO S THIS AFTERNOON INTO THIS
EVENING...LINGERING LONGEST OVER THE SE CORNER OF LAKE SUPERIOR. A
LOW OVER THE LOWER GREAT LAKES THIS AFTERNOON WILL SHIFT TO THE NEW
ENGLAND STATES BY MONDAY AFTERNOON AS HIGH PRESSURE OVER S CENTRAL
CANADA AND THEN N PLAINS BUILDS ACROSS THE UPPER GREAT LAKES. THE
AREA OF HIGH PRESSURE WILL MOVE LITTLE THROUGH THURSDAY...SLOWLY
EXPANDING S. AS THE LOW MOVES/DEEPENS ACROSS QUEBEC ON TUESDAY...A
TROUGH WILL DEVELOP OVER LAKE SUPERIOR. LOOK FOR THE WEAK TROUGH TO
WEAKEN QUICKLY THURSDAY EVENING. THE EXPECT WEAK HIGH PRESSURE WILL
BEING TO BUILD ACROSS THE UPPER GREAT LAKES ON THURSDAY. WINDS
SHOULD REMAIN LESS THAN 25KTS THROUGH THE PERIOD.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  DENSE FOG ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249>251.

LAKE MICHIGAN...
NONE.
&&

$$

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





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