Area Forecast Discussion
Issued by NWS Marquette, MI

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 291926
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
326 PM EDT WED OCT 29 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 324 PM EDT WED OCT 29 2014

A 991MB SURFACE LOW TO THE NORTHEAST OF JAMES BAY IN NORTHERN
QUEBEC SWEPT A SURFACE TROUGH ACROSS THE UPPER GREAT LAKES REGION
LAST NIGHT. THIS HAS LED TO A POCKET OF COLD AIR AT 850MB (AROUND
-5C) TO HELP PRODUCE SOME LAKE EFFECT RAIN/SNOW SHOWERS THIS PAST
MORNING. ALTHOUGH ABUNDANT LOW LEVEL MOISTURE CAN BE SEEN WITH THE
LOW CLOUDS OVER MUCH OF THE UPPER GREAT LAKES REGION...DRYING ALOFT
IN ASSOCIATED WITH THE APPROACHING UPPER/SURFACE RIDGE HAS LED TO
THE CLOUDS TOPS QUICKLY LOWERING THIS MORNING FROM 8KFT TO 5KFT BY
14Z. THIS HAS STAYED STEADY THROUGH THE AFTERNOON AND IS HELPING TO
LIMIT THE STRENGTH OF THE SHOWERS OVER NORTHCENTRAL AND NORTHEAST
UPPER MICHIGAN UNDER THE NORTHWESTERLY FLOW OFF LAKE SUPERIOR. WILL
CONTINUE TO SHOW A GRADUAL DIMINISHING TREND IN THAT AREA THIS
EVENING WITH THE TEMPERATURES ALOFT SLIGHTLY WARMING AND REDUCING
THE OVER LAKE INSTABILITY. OVER THE WEST...THE BACKING WINDS WITH
THE HIGH PRESSURE RIDGE (FROM A HIGH MOVING OUT OF THE MID
MISSISSIPPI VALLEY) AND THE INCREASED SUBSIDENCE HAS DIMINISHED THE
SHOWERS (WEBCAMS INDICATING PAVEMENT DRYING)...BUT ANOTHER AREA OF
LOW CLOUDS MOVING EAST INTO THE AREA WILL KEEP MUCH OF THAT AREA
CLOUDY TONIGHT. OVER THE CENTRAL AND EAST AWAY FROM LAKE
SUPERIOR...THERE IS THE POTENTIAL OF THE CLOUD COVER SCATTERING OR
EVEN CLEARING OUT FOR A PERIOD AFTER DIURNAL HEATING IS LOST. DID
TRY TO SHOW A QUICK PERIOD OF PARTLY-MOSTLY CLOUDY SKIES IN THAT
AREA THIS EVENING BEFORE THE LOW CLOUDS SLIDE BACK IN.

FOR THE REST OF TONIGHT INTO THURSDAY...THERE ARE A COUPLE
SHORTWAVES THAT WILL BE APPROACHING THE NORTH CENTRAL CONUS. THE
FIRST ONE IS CURRENTLY ROUNDING THE WEAK UPPER RIDGE IN THE DAKOTAS
AND WILL DIVE SOUTHEAST OF THE AREA. A WEAK SURFACE LOW DEVELOPING
ALONG THIS SHORTWAVE WILL STRETCH A WEAK TROUGH NORTH ACROSS THE
UPPER GREAT LAKES LATE TONIGHT AND INTO THURSDAY. WHILE THERE WILL
BE PLENTY OF MOISTURE AS THIS WEAK UPPER TROUGH SLIDES THROUGH THE
AREA...THE FORCING IS FAIRLY LIMITED AND LIQUID AMOUNTS SHOULD
GENERALLY STAY BELOW 0.20 INCH. THE GREATEST AMOUNTS WILL BE OVER
THE NORTHWEST PART OF UPPER MICHIGAN...WHERE THE COMBINATION OF
BACKING WESTERLY TO NORTHWESTERLY FLOW OFF THE LAKE AND INCREASING
LOW LEVEL CONVERGENCE BEHIND THE TROUGH/LOW IN THE AFTERNOON WILL
SUPPORT HIGHER AMOUNTS AND A LITTLE BETTER COVERAGE IN THE SHOWERS.
ALTHOUGH THE LOWERING OF THE CLOUD TOPS CREATES SOME CONCERN ON THE
POTENTIAL FOR ICE CRYSTALS IN THE CLOUD THIS AFTERNOON AND
EVENING...WILL CONTINUE TO MENTION SOME POTENTIAL OF SNOW DUE TO THE
STRONGER SHOWERS LIKELY RISING A LITTLE HIGHER AND INTO COLDER
TEMPERATURES. OTHERWISE...ONCE THE DEEP MOISTURE ARRIVES LATE
TONIGHT WITH THE WEAK SHORTWAVE EXPECT PLENTY OF ICE CRYSTALS IN THE
CLOUD AND THE PRECIP TYPE DEPENDS ON THE NEAR SURFACE TEMPERATURES.
WETBULB0 VALUES HAVE BEEN HANDLING THESE EVENTS WELL OVER THE LAST
MONTH AND WILL CONTINUE TO LEAN ON THAT FOR THE RAIN/SNOW FORECAST
THROUGH TOMORROW. MODELS INDICATING WETBULB0 VALUES BETWEEN
900-2100FT SO WILL GO WITH RAIN/SNOW (OVER THE HIGHER TERRAIN) TO
MAINLY RAIN OVER THE AREA TONIGHT INTO THURSDAY AFTERNOON. THEN AS
THE COLDER AIR STARTS SURGING IN LATE IN THE AFTERNOON INTO
THURSDAY EVENING...SHOULD SEE A QUICK TRANSITION TO ALL SNOW. A
SECONDARY AND STRONGER SHORTWAVE DIVING SOUTH-SOUTHEAST ACROSS
MANITOBA AND NORTHWEST ONTARIO ON THURSDAY WILL BE JUST TO THE
NORTHWEST OF LAKE SUPERIOR AT 00Z ON FRIDAY. THIS FEATURES WILL
DRIVE THE WINTER-LIKE WEATHER FOR THURSDAY NIGHT INTO FRIDAY.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 404 AM EDT WED OCT 29 2014

NAM SHOWS 850-500 MB Q-VECTOR CONVERGENCE AND DEEP MOISTURE 12Z TUE
THAT MOVES ACROSS THE CWA ON TUE AND BOTH MOVE OUT ON FRI. LAKE
EFFECT PCPN WILL BE THE WEATHER MAKER THIS FORECAST PERIOD WITH
TEMPERATURES COLD ENOUGH FOR RAIN AND SNOW. WITH THE COLDER AIR
ARRIVING...BUMPED UP THE SNOW RATIOS AND BECAUSE OF THIS...STORM
TOTAL SNOWFALL AMOUNTS FROM THU AFTERNOON TO FRIDAY EVENING RANGE
FROM AROUND 0.5 INCH IN THE SOUTHERN CWA UP TO 6 INCHES IN THE HURON
MOUNTAINS WHICH IS AN INCREASE FROM THE PREVIOUS FORECAST AND THE
TOTALS SEEM REASONABLE BASED ON THE COLD AIR COMING ACROSS LAKE
SUPERIOR AND THE NORTH TO NORTHEAST WIND DIRECTION. GFS AND NAM ARE
SHOWING 850 MB TEMPERATURES DROPPING TO -10C TO -12C THU NIGHT AND
WITH LAKE SUPERIOR TEMPERATURES RANGING FROM 6C TO 8C...THAT IS
ENOUGH LAKE-850 MB DELTA-T FOR LAKE EFFECT PCPN AND SNOW. DID NOT
MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR TEMPERATURES.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB RIDGE OVER THE PLAINS
12Z SAT WITH A SFC RIDGE OF HIGH PRESSURE OVER THE AREA. THE UPPER
RIDGE MOVES INTO THE UPPER GREAT LAKES 12Z SUN. A 500 MB TROUGH
MOVES INTO THE NORTHERN PLAINS 12Z MON AND THIS TROUGH MOVES INTO
THE UPPER GREAT LAKES 12Z TUE. A SFC COLD FRONT MOVES THROUGH THE
AREA MON NIGHT INTO TUE. FORECAST WILL START OUT DRY SAT INTO SUNDAY
AND THEN WILL HAVE SLIGHT CHANCE POPS FOR MON INTO TUE AS AN UPPER
LEVEL TROUGH APPROACHES. TEMPERATURES WILL START A WARMING TREND
THIS FORECAST PERIOD WITH TEMPERATURES APPROACHING NORMAL BY THE END
OF THE FORECAST PERIOD.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 150 PM EDT WED OCT 29 2014

NORTHWEST FLOW BETWEEN A LOW IN NORTHERN QUEBEC AND A HIGH PRESSURE
RIDGE IN MINNESOTA CONTINUES TO PRODUCE MVFR CEILINGS AND A FEW LAKE
EFFECT SHOWERS ACROSS UPPER MICHIGAN. WITH THE CONVECTIVE LOOK OF THE
CLOUDS OVER THE AREA THIS AFTERNOON...DO HAVE A LITTLE BIT OF A
CONCERN THAT THERE COULD BE A BRIEF PERIOD OF SCATTERING TO CLEARING
OF THE CLOUDS AROUND/AFTER SUNSET BEFORE ADDITIONAL LOW LEVEL
MOISTURE WORKS BACK INTO THE AREA. HAVE OPTED TO KEEP KCMX/KIWD AT
MVFR BUT DID TREND KSAW UP TO VFR FOR A BRIEF PERIOD DUE TO THE
BACKING WINDS AIDING A LITTLE BIT OF DOWNSLOPE FLOW. OTHERWISE...AS A
SURFACE TROUGH MOVES INTO THE AREA LATE TONIGHT INTO THURSDAY EXPECT
SCATTERED TO NUMEROUS SHOWERS TO DEVELOP FROM WEST TO EAST THROUGH
THAT PERIOD WITH MVFR CEILINGS. THERE MAY BE BRIEF PERIODS OF
RAIN/SNOW MIX AT KCMX...BUT CONFIDENCE WAS TOO LOW TO LOWER
VISIBILITIES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 324 PM EDT WED OCT 29 2014

HIGH PRESSURE CENTERED IN THE MID MISSISSIPPI VALLEY CONTINUES TO
STRETCH A RIDGE NORTH OVER THE UPPER GREAT LAKES REGION. THIS WILL
CONTINUE TO WEAKEN WINDS TONIGHT BELOW 15KTS. A WEAK LOW PRESSURE
SYSTEM MOVING ACROSS UPPER MICHIGAN THURSDAY AFTERNOON WILL
STRENGTHEN AS IT MOVES SOUTHEAST THROUGH THE REST OF THE GREAT
LAKES THURSDAY NIGHT INTO FRIDAY. THAT LOW...IN COMBINATION WITH A
STRONG HIGH IN CENTRAL CANADA AND THE NORTHERN PLAINS WILL LEAD TO
STRONG NORTHERLY FLOW ACROSS LAKE SUPERIOR. AT THE PRESENT
TIME...EXPECT GALES UP TO 40KTS THURSDAY NIGHT INTO FRIDAY
MORNING AND WILL CONTINUE THE EXISTING GALE WATCH. THE GALES WILL
COME TO AN END ON FRIDAY AFTERNOON AS THE HIGH PRESSURE RIDGE BUILDS
OVER THE AREA. THIS WILL LEAD TO WINDS DIMINISHING BELOW 20KTS ON
FRIDAY NIGHT AND CONTINUING INTO SATURDAY EVENING. AS THE HIGH
DEPARTS AND ANOTHER LOW DEVELOPS IN THE NORTHERN PLAINS...SOUTHERLY
FLOW WILL DEVELOP OVER LAKE SUPERIOR ON SATURDAY NIGHT (WINDS UP TO
25KTS) AND CONTINUE INTO MONDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY AFTERNOON FOR
     LSZ249>251-266-267.

  GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
     LSZ162-240>242-263.

  GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY AFTERNOON FOR
     LSZ243>248-264-265.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...SRF
LONG TERM...07
AVIATION...SRF
MARINE...SRF






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