Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KMQT 271129
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
729 AM EDT SUN JUL 27 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 451 AM EDT SUN JUL 27 2014

SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE THROUGH CENTRAL UPPER
MICHIGAN THIS MORNING AS WEAK SHORTWAVE FRONT-RUNNING MAIN UPPER
LEVEL DISTURBANCE CURRENTLY LOCATED OVER NORTHERN MN. BEST
INSTABILITY LOCATED WELL TOT HE SOUTH OF THE AREA OVER WI WITH
MUCAPES AT OR JUST ABOVE 1000 J/KG. WILL NEED TO MONITOR SOUTHERN
END OF THE LINE OF SHOWERS AND THUNDERSTORMS FOR INTENSIFICATION
EARLY THIS AM AS THEY FEED ON MORE UNSTABLE AIR.

5H LOW TO SWING THROUGH THE REGION TODAY BRINGING SHOWERS AND A FEW
THUNDERSTORMS TO THE U.P.  BEST INSTABILITY AND 850-500 MB Q VECTOR
CONVERGENCE REMAINS FOCUSED TO THE SOUTH OF THE AREA THROUGH THE DAY
THUS WILL SEE MORE SHOWERS THAN THUNDERSTORMS. TIMING OF THE ENDING
OF PRECIPITATION REMAINS THE QUESTION. LATEST MODEL RUNS WERE
SLIGHTLY MORE PROGRESSIVE IN MOVING THE PRECIPITATION OUT AND HAVE
FOLLOWED THIS TREND FOR THIS FORECAST. WITH DECENT 850-500 MB Q
VECTOR DIVERGENCE MOVING INTO THE WESTERN UPPER PENINSULA THIS
AFTERNOON AND WITH DRIER AIR WORKING IN ONCE THE WINDS SHIFT TO THE
NORTH...PRECIPITATION WILL END FROM NW TO SE ACROSS THE AREA DURING
THE AFTERNOON AND EARLY EVENING.

IN ADDITION TO THE PRECIPITATION...AREAS OF FOG WILL PLAGUE PORTIONS
OF CENTRAL AND EASTERN UPPER MICHIGAN THIS MORNING AS LIGHT
ONSHORE/UPSLOPE FLOW CONTINUES AND GRADUALLY BECOMES EASTERLY AHEAD
OF THE SFC LOW. THERE MAY BE SOME LOCALLY DENSE FOG OUT EAST WHERE
THE LACK OF CLOUD COVER OVERNIGHT ENHANCES FOG PROBABILITIES. THE
FOG WILL GRADUALLY LIFT LATER THIS AM AS WINDS BEGIN TO SHIFT TO THE
N AND DRIER AIR BEGINS TO FILTER IN AT THE SFC. AS FOR
TEMPERATURES...PREFERRED A SLIGHTLY WARMER FORECAST AS 850 MB TEMPS
ONLY FALL OFF LATER IN THE DAY AS THE LOW SHIFTS SE.

FOR TONIGHT...HIGH PRESSURE BEGINS TO BUILD IN BEHIND DEPARTING
SYSTEM. NORTHERLY WINDS CONTINUE THROUGHOUT THE NIGHT AND BEGIN TO
RELAY TOWARD DAYBREAK. CLEAR SKIES COMBINED WITH COLD AIR ADVECTION
AD DRIER AIR WORKING IN WILL HELP DROP TEMPERATURES BELOW SEASONAL
NORMALS WITH THE MID 40S COMMON AWAY FROM THE INFLUENCES OF THE
GREAT LAKES.

.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 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 728 AM EDT SUN JUL 27 2014

UPSLOPE FLOW AT KCMX PRODUCING LIFR CONDITIONS THERE THIS MORNING.
SIMILAR UPSLOPE CONDITIONS AT KSAW BUT LIFR/IFR CIGS/VSBYS HAVE NOT
YET BECOME PERSISTENT THERE...BUT SHOULD DO SO AS LIFR CONDITIONS
REPORTED CLOSE BY THAT LOCATION. EXPECT CIGS/VSBYS TO IMPROVE AT
KCMX BY MID MORNING AS WINDS SHIFT THERE AND REDUCE UPSLOPE
COMPONENT...BUT LOWER CIGS TO PERSIST A BIT LONGER AT KSAW AS
UPSLOPE FLOW TO LAST A LITTLE LONGER THERE. KIWD TO SEE MVFR
CONDITIONS IN -SHRA AND WILL BE THE FIRST TO GO VFR LATER TODAY AS
DRIER AIR MOVES IN BEHIND DEPARTING LOW PRESSURE SYSTEM. VFR
CONDITIONS EXPECTED AT THE OTHER TWO TAF SITES BY MID TO LATE
AFTERNOON WITH KSAW THE LAST TO SEE CONDITIONS IMPROVE. VFR
CONDITIONS TO PREVAIL THROUGH THE REMAINDER OF THE FORECAST.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 AM EDT SUN JUL 27 2014

SFC LOW WILL TRACK ACROSS THE UPPER PENINSULA TODAY...BRINGING
INCREASING WINDS ON THE BACKSIDE OF THIS SYSTEM. WESTERN LAKE
SUPERIOR WILL SEE WINDS INCREASING THIS MORNING WITH GUSTS REACHING
AS HIGH AS 22 KTS...THEN DIMINISHING THROUGH THE AFTERNOON. OVER
EASTERN LAKE SUPERIOR...AS FLOW SHIFTS TO THE NORTH WINDS PICK UP
THIS AFTERNOON WITH GUSTS AS HIGH AT 20 KTS. WINDS TO GRADUALLY
RELAX DURING THE EVENING AND OVERNIGHT HOURS WITH SPEEDS EVENTUALLY
DROPPING TO LESS THAN 15 KNOTS DURING THE LATE EVENING HOURS. WINDS
TO REMAIN BELOW 15 KNOTS THROUGH THE REMAINDER OF THE FORECAST AS
HIGH PRESSURE BUILDS INTO THE REGION.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  DENSE FOG ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ264-266-
     267.

  DENSE FOG ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ244>248-
     265.

  DENSE FOG ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249>251.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...RJT
LONG TERM...SRF
AVIATION...RJT
MARINE...RJT






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.