Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 010815
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
415 AM EDT TUE SEP 1 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015

MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.

PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.

THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON AUG 31 2015

MORE 80S ARE ON THE WAY THROUGH AT LEAST SATURDAY. THE 500MB RIDGE
SET UP FROM W TX-LOWER MI...EXTENDING UP THROUGH HUDSON BAY WILL
FLATTEN OUT ONLY SLIGHTLY...BEFORE REBOUNDING OVER THE UPPER GREAT
LAKES WEDNESDAY NIGHT THROUGH AT LEAST SATURDAY.

WE WILL HAVE A LONG STRETCH OF TEMPERATURES AT OR ABOVE
80F...PROBABLY 8 DAYS IN TOTAL. IT WILL LIKELY END UP THE LONGEST
STRETCH IN 2 YEARS...AND TIED FOR THE LONGEST STRETCH IN 9 YEARS.
THE LAST TIME WE HAD MORE THAN 7 DAYS IN A ROW WAS IN 2006.

ALTHOUGH A NEARING SFC TROUGH TUESDAY NIGHT WILL KEEP LOW POPS OVER
MAINLY E LAKE SUPERIOR...IT WILL WILL HAVE TO OVERCOME PLENTY OF DRY
AIR. PW VALUES DO INCREASE TO 1.7 TO NEAR 2IN E.

ANY WIDESPREAD PRECIP WILL LIKELY HOLD OFF UNTIL SUNDAY OR EVEN
SUNDAY NIGHT UNTIL MONDAY. THE GFS IS A BIT SLOWER THAN THEN ECMWF.
THE APEX OF THE 500MB RIDGE WILL SHIFT W ACROSS THE LOWER GREAT
LAKES AND NEW ENGLAND STATES FOR THE LATTER HALF OF THE
WEEKEND...WITH SW FLOW MOVING INTO OUR AREA. TIMING OF THE NEXT
500MB LOW OR SIGNIFICANT WAVE EJECTING OUT OF THE W TROUGH IS STILL
UNCERTAIN. HOWEVER...INITIAL LOOKS SHOW THAT NEXT TUESDAY OR
WEDNESDAY COULD GIVE US A BETTER CHANCE OF SOME COOLER
AIR...ALTHOUGH IT MAY BE SHORT LIVED.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE SEP 1 2015

EXPECT VFR CONDITIONS TO PREVAIL AT THE SITES THROUGH MUCH OF THE
REST OF THE PERIOD. KSAW AND CMX WILL SEE THE POTENTIAL FOR PATCHY
GROUND FOG LATE TONIGHT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015

SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
  DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LMZ248-250.

&&

$$

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



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