Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Text Only | 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 271105
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
705 AM EDT MON OCT 27 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 422 AM EDT MON OCT 27 2014

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE UPPER GREAT
LAKES WITH A TROUGH IN THE NORTHERN ROCKIES THIS MORNING WITH
SHORTWAVES OVER THE CANADIAN PRAIRIES. THESE SHORTWAVES COMBINE TO
FORM A CLOSED 500 MB LOW ACCORDING TO THE NAM OVER NORTHERN MN 12Z
TUE.

NAM SHOWS 850-500 MB Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE
MOVING THROUGH THE CWA THIS FORECAST PERIOD THROUGH TONIGHT. DID NOT
MAKE TOO MANY BIG CHANGES TO THE GOING FORECAST. ONE CHANGE MADE WAS
BUMPED THE CATEGORY OF THUNDER UP TO CHANCE AS THERE IS A LOT MORE
LIGHTNING OCCURRING ACROSS LAKE SUPERIOR AND THE WESTERN U.P. THIS
MORNING THEN PREVIOUSLY THOUGHT AND SCATTERED THUNDERSTORMS LOOK TO
BE THE WAY TO GO RATHER THAN ISOLATED BASED ON PRESENT TRENDS. ALSO
ADDED IN SOME SMALL HAIL AS THERE HAVE BEEN SOME REPORTS OF PEA
SIZED HAIL AND DID GET SOME AT THE OFFICE AND PUT SMALL HAIL IN THE
FORECAST FOR EARLY THIS MORNING AS DRY AIR UNDERNEATH ELEVATED
CONVECTION HAS BEEN ENOUGH TO GET SMALL HAIL OUT OF THE STORMS. KEPT
IN LIKELY POPS ACROSS THE EAST HALF OF THE CWA THIS MORNING AS THE
CONVECTION WILL FILL IN AND THEN HAVE LIKELY POPS AGAIN TONIGHT OVER
THE EASTERN CWA WITH MORE ENERGY HEADING UP WITH THE CLOSED LOW
NEARBY. DID NOT MAKE MANY CHANGES TO TEMPERATURES. LOOKS LIKE THERE
WILL BE PERIODS OF SHOWERS THROUGH THIS FORECAST PERIOD.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 450 AM EDT MON OCT 27 2014

...ACTIVE AND UNSETTLED PATTERN WITH COOLING TREND BY LATE WEEK...

SHORTWAVE TROUGH CLOSES IN ON UPPER GREAT LAKES TUESDAY MORNING. SFC
LOW AROUND 995MB OVER EASTERN CWA LIFTS OVER EASTERN LK SUPERIOR BY
MIDDAY TUESDAY CLOSER TO BETTER H7-H5 Q-VECTOR CONVERGENCE WITH THE
SHORTWAVE TROUGH AND ALSO WHERE H25 DIVERGENCE ALOFT IS MAXIMIZED IN
LEFT EXIT REGION OF JET STREAK OVER CNTRL GREAT LAKES. DRY SLOT WILL
BE IN PLAY TO THE SOUTH OF SFC TROUGH AND ON SOUTHERN EDGE OF UPPER
LOW. NAM/GFS SOUNDINGS INDICATE LINGERING MOISTURE BENEATH MID-LEVEL
DRYING SHOULD LEAD TO LULL IN RAIN CHANCES ON TUESDAY WITH EVEN SOME
POTENTIAL THAT SKIES TRY TO PARTIALLY CLEAR OUT LATE MORNING INTO
THE AFTN. HAVE TO SEE ON THAT ONE. OVERALL THOUGH...POPS WILL BE IN
THE SLIGHT CHANCE RANGE MOST OF TUESDAY...EXCEPT OVER THE FAR EAST
CWA IN THE MORNING AS CONVERGENCE IN THE VCNTY OF SFC LOW ALONG WITH
WARM AIR ADVECTION MAY ALLOW SHOWERS TO LINGER.

ALSO SHOULD SEE RAIN INCREASE LATE IN THE DAY OVER THE WEST ONCE THE
UPPER LOW AND SFC LOW MOVE BY TO THE EAST...BRINGING IN A MOIST AND
CYCLONIC NORTHWEST FLOW. BETTER CHANCE FOR RAIN WILL BE TUESDAY
NIGHT OVER THE WEST AS THIS REGIME COMBINES WITH COLD AIR ADVECTION
WITH H85 TEMPS FALLING TO -3C AFTER MIDNIGHT. GIVEN WATER TEMPS
AROUND 6C THERE WILL BE ENOUGH OVER-WATER INSTABILITY FOR LAKE
ENHANCED PRECIP. WBZERO HEIGHTS FALLING BLO 1000 FT AGL INDICATE
SNOW WILL BEGIN TO MIX WITH RAIN FOR HIGHER TERRAIN AREAS OF WEST
AND NCNTRL CWA. NO SNOW ACCUMULATION THOUGH AS IT WILL ONLY BE A MIX
AND WITH TEMPS EXPECTED TO BE IN THE MID 30S. AS THIS COOL AIR MOVES
IN...WINDS WILL BE GUSTY...FIRST FM THE WEST ON THE KEWEENAW LATE ON
TUESDAY INTO TUESDAY EVENING...THEN ALONG LK SUPERIOR SHORE INTO
WEDNESDAY MORNING MAINLY FROM COPPER HARBOR TO MARQUETTE AND TO
GRAND MARAIS. WIND GUSTS DURING THESE TIMES MAY REACH OVER 40 MPH.

RAIN AND SNOW SHOWERS SHOULD GRADUALLY DIMINISH ON WEDNESDAY DUE TO
DECREASING MOISTURE AND DRYING BLO CLOUD BASE...LEADING TO A MORE
INVERTED-V LOOK. KEPT SMALL CHANCES IN FOR LAKE EFFECT RAIN AND SNOW
SHOWERS INTO WEDNESDAY NIGHT...MAINLY TO EAST OF MUNISING AS CLOUD
BEARING WINDS ARE WNW. LOWEST TEMPS WITHIN THE LAKE EFFECT LAYER ARE
-6C...MARGINAL FOR A 13C DELTA T/S NEEDED FOR PURE LAKE EFFECT
PROCESSES. SEEMS ESPECIALLY MARGINAL SINCE BACKGROUND FLOW BY
WEDNESDAY EVENING IS ANTICYCLONIC WITH SFC RIDGE MOVING OVER
WESTERN UPR MICHIGAN. WORTH A SMALL CHANCE...BUT NO MORE. COULD SEE
TEMPS DIP TOWARD FREEZING OVER WESTERN UPR MICHIGAN. THURSDAY MORE
OR LESS A SANDWICH DAY IN TERMS OF BEING BTWN EXITING UPPER LOW INTO
QUEBEC AND STRONGER/REINFORCING SHORTWAVE TROUGH DIGGING SOUTH ACROSS
MANITOBA. THOUGH IT WILL STILL BE COOLER THAN NORMAL IN THE 40S...
WINDS ARE LIGHT FOR MOST OF THE DAY AND ONLY CHANCES OF RAIN ARE
OVER LK SUPERIOR AND THE KEWEENAW LATE IN THE DAY.

STRONG SHORTWAVE TROUGH DIGS ACROSS THE AREA ON THURSDAY NIGHT WHICH
BUCKLES UPPER LEVEL FLOW FM WNW TO NNW. MODELS ARE NOT TOGETHER YET
ON EXTENT OF WIDESPREAD PRECIP WITH THE SHORTWAVE. GFS MUCH MORE
BULLISH ON QPF COMPARED TO LESS DEVELOPED ECMWF. THEY CERTAINLY DO
AGREE ON A SHOT OF COLD AIR DIVING ACROSS THE AREA LATE THURSDAY
NIGHT INTO FRIDAY. H85 TEMPS DOWN TO AROUND -11C OR -12C...PLENTY
LOW ENOUGH FOR LAKE ENHANCED SNOW SHOWERS OR JUST PURE LAKE EFFECT
SNOW SHOWERS. AT THIS POINT...LOOKING LIKE ONLY PURE LAKE EFFECT AS
THERE IS SHARP DRYING ABOVE H8 AND MID LEVEL Q-VECTOR DIVERGENCE AND
SUBSIDENCE QUICKLY SPREADING OVER WESTERN GREAT LAKES ON FRIDAY.
COULD SEE MINOR SNOW ACCUMS DURING THE HEAVIER SNOW SHOWERS THURSDAY
NIGHT INTO FRIDAY MORNING. WILL BE BLUSTERY AND COOL WITH HIGHS NEAR
LK SUPERIOR STUCK IN THE 30S AND BARELY REACHING 40 DEGREES OVER FAR
SCNTRL. THERMAL TROUGHING PERSISTS INTO SATURDAY OVER EASTERN LK
SUPERIOR THOUGH LOW-LEVELS BECOME ANTICYCLONIC IN A HURRY AS SFC
RIDGE BUILDS ACROSS. KEPT IN SMALL CHANCES FOR LK EFFECT RAIN AND
SNOW SHOWERS ON SATURDAY...BUT THEY WILL DWINDLE WITH THE ARRIVAL
OF THE RIDGE. AFTER A CHILLY NIGHT BENEATH THE RIDGE ON SATURDAY
NIGHT...WARM AIR ADVECTION ON THE RETURN FLOW SIDE OF THE RIDGE
WILL BRING IN ANOTHER CHANCE OF RAIN SHOWERS BY LATE IN THE WEEKEND.
QUITE AN ACTIVE PATTERN FOR THIS WEEK.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 705 AM EDT MON OCT 27 2014

INITIALLY...VFR CONDITIONS AT KIWD/KCMX/KSAW WILL CHANGE AS
INCREASINGLY MOIST AIR FLOWS INTO THE AREA. EXPECT CIGS TO FALL TO
MVFR BY THIS AFTERNOON AND THEN TO IFR THIS EVENING. SHRA WILL
CONTINUE TO BE SCATTERED AROUND THE AREA THRU THE DAY AND INTO THE
EVENING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 422 AM EDT MON OCT 27 2014

HIGH PRESSURE MOVING INTO THE REGION WILL LEAD TO DECREASING WINDS
TODAY. AFTER A BRIEF PERIOD WITH WINDS LESS THAN 20 KTS WITH THE
HIGH PRESSURE...SE WINDS INCREASE TO 30 KTS OVER MAINLY EASTERN LAKE
SUPERIOR ON MONDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. ONCE
THIS LOW MOVES TO THE EAST OF LAKE SUPERIOR ON TUESDAY...WEST WINDS
TO 30 KTS AND POSSIBLY UP TO GALE FORCE OF 35 KTS WILL DEVELOP LATE
TUESDAY INTO TUESDAY NIGHT. WINDS WILL THEN SHIFT NORTHWEST AND STAY
UP TO 30 KTS INTO WEDNESDAY...BEFORE GRADUALLY DIMINISHING TO LESS
THAN 25 KTS BY WEDNESDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM MAY MOVE
THROUGH THE REGION LATE THIS WEEK...POSSIBLY LEADING TO GALES TO 35
KTS.
&&

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

$$

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






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