Area Forecast Discussion
Issued by NWS Marquette, MI

Home | 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 210746
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
346 AM EDT THU AUG 21 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 344 PM EDT WED AUG 20 2014

AN UPPER LOW LOCATED OVER EASTERN UPPER MICHIGAN HAS CONTINUED ITS
SLOW EASTWARD PROGRESSION THIS AFTERNOON...WITH A BROAD 1009MB LOW
STRETCHING FROM EASTERN LAKE SUPERIOR THROUGH NORTHERN LOWER
MICHIGAN. ABUNDANT MOISTURE WRAPPING AROUND THESE LOWS HAS LED TO
PLENTY OF LOW CLOUDS OVER THE ENTIRE AREA. THE FOG THAT
OCCURRED OVER THE KEWEENAW PENINSULA THIS MORNING HAS
DIMINISHED...BUT WEBCAMS ALONG THE LAKE SUPERIOR SHORELINE IN THE
KEWEENAW AND ALSO AT MUNISING INDICATE DENSE FOG OVER THE LAKE.
THAT MATCHES OBSERVATIONS FROM SHIPS THROUGH THE DAY OVER
CENTRAL/EASTERN LAKE SUPERIOR THROUGH THE DAY. THERE ARE STILL A
FEW LIGHT SHOWERS/DRIZZLE OVER SOUTHEASTERN MARQUETTE COUNTY AND
NORTHWEST DELTA COUNTY...ALONG WITH PORTIONS OF SCHOOLCRAFT/LUCE
 COUNTIES. AFTERNOON TEMPERATURES ARE GENERALLY IN THE 60S ACROSS
THE U.P. AND IS ABOUT 10 DEGREES BELOW NORMAL.

THE UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL DRIFT TO THE
EAST-SOUTHEAST TONIGHT OVER LAKE HURON AND THEN INTO FAR SOUTHEAST
ONTARIO ON THURSDAY. AS THIS OCCURS...IT WILL PULL THE DEEP
MOISTURE AND FORCING OUT WITH IT AND LEAVE SOME LINGERING LOW LEVEL
MOISTURE OVER AT LEAST THE NORTHEAST TWO THIRDS OF THE CWA FOR
TONIGHT. THUS...WILL OPT TO STICK WITH PERSISTENCE WITH THE LOW
CLOUDS OVER MUCH OF THE AREA AND ONLY TRY TO SCATTERED THE CLOUDS
OUT SOUTHWEST OF A LINE FROM ONTONAGON TO IRON MOUNTAIN. WITH THE
AMOUNT OF LOW LEVEL MOISTURE PRESENT...EXPECT FOG TO DEVELOP AGAIN
TONIGHT NEAR LAKE SUPERIOR AND OVER THE EAST. THOSE AREAS WILL BE
AIDED BY LIGHT FLOW OFF LAKE SUPERIOR AND SOME UPSLOPE FORCING TO
AID THE LOW CLOUDS. THINK THE LOWEST VISIBILITIES WOULD BE OVER THE
KEWEENAW PENINSULA WHERE THEY HAVE THE FAVORABLE EASTERLY FLOW
DEVELOPING OVERNIGHT...BUT IT WILL LARGELY DEPEND ON THE EXTENT OF
THE FOG OVER SOUTH CENTRAL LAKE SUPERIOR (UNCERTAIN AT THIS POINT).
IN ADDITION...IF SOME CLEARING OCCURS OVER THE FAR SOUTHWEST...THAT
MAY AID IN FOG DEVELOPMENT OUTSIDE OF WHERE THE BEST LOW LEVEL
MOISTURE IS LOCATED.

THE DEVELOPING BROAD LOW OVER THE CENTRAL/NORTHERN PLAINS WILL BE
THE ITEM OF FOCUS FOR THURSDAY...AS IT SLOWLY LIFTS NORTHEAST
TOWARDS THE CWA. LATEST TRENDS IN THE 12Z MODELS IS FOR THE LOW AND
WARM FRONT TO BE A LITTLE SLOWER AND SUPPRESSED TO THE SOUTH THAN
SEEN YESTERDAY. THAT FARTHER SOUTH TREND WILL LIKELY KEEP MUCH OF
THE PRECIPITATION TO THE SOUTH (ALONG THE WARM FRONT IN
NORTHERN/CENTRAL WISCONSIN) OR WEST (TIED WITH THE SHORTWAVE LIFTING
NORTHEAST THROUGH NORTHERN MINNESOTA) OF THE CWA DURING THE DAYTIME
HOURS ON THURSDAY. WILL SLOWLY SPREAD SLIGHTS AND THEN CHANCE POPS
NORTHEAST OVER THE SOUTHWEST THIRD/HALF OF UPPER MICHIGAN DURING THE
AFTERNOON HOURS...LARGELY TIED TO THE BROAD MID-LEVEL WAA MOVING
OVER THAT AREA. ELSEWHERE...EXPECT A GENERALLY MOSTLY CLOUDY SKY DUE
TO THE DEPARTING LOW LEVEL MOISTURE AND INCREASING MID LEVEL
MOISTURE. WILL CONTINUE TO MENTION SOME THUNDER CHANCES DURING THE
AFTERNOON OVER THE SOUTHWEST THIRD/HALF...BUT WITH THE LATEST TRENDS
IN THE MODELS KEEPING THE WARM FRONT A LITTLE FARTHER TO THE
SOUTH...THINK SEVERE CHANCES ARE A LITTLE LOWER THAN THOUGHT
YESTERDAY. 0-6KM SHEAR IS MARGINAL (AROUND 30KTS) AND WITH 350-800
J/KG OF MU/ML CAPE NOSING INTO GOGEBIC COUNTY...THINK THAT AREA
WOULD HAVE THE BEST OPPORTUNITY FOR STRONGER STORMS LATE THURSDAY
AFTERNOON IF THEY DEVELOP FARTHER TO THE NORTH THAN EXPECTED.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM EDT THU AUG 21 2014

NAM SHOWS A 500 MB RIDGE OVER THE GULF COAST WITH A CLOSED 500 MB
LOW OVER THE DESERT SW AND A TROUGH IN THE WESTERN U.S. 12Z FRI. THE
RIDGE BUILDS INTO THE UPPER GREAT LAKES 12Z SAT WITH A SHORTWAVE
EJECTED OUT OF THE DESERT SW INTO THE NORTHERN PLAINS. THE TROUGH IN
THE WESTERN U.S. MOVES INTO THE NORTHERN ROCKIES AND NORTHERN PLAINS
12Z SUN.

DIFFICULT FORECAST COMING UP AS THERE IS REALLY NOTHING TO PIN DOWN
ON HERE AS THINGS ARE VERY SUBTLE. BIG BUST POTENTIAL FOR
TEMPERATURES EXIST DEPENDING ON HOW MUCH OR HOW LITTLE CLOUD COVER
THERE IS AND THIS ALL HINGES ON HOW MUCH OR HOW LITTLE CONVECTION
OCCURS. I WENT MORE TOWARDS A DRIER SOLUTION WITH MORE SUNSHINE AND
WENT MORE WITH SLIGHT CHANCE POPS FOR ALMOST EVERY PERIOD AND WARMER
AND HUMID CONDITIONS FOR THIS FORECAST PERIOD. THINKING IS MAJORITY
OF CONVECTION WILL STAY TO THE SOUTH AND WEST OF AREA WITH LEFTOVER
STUFF COMING THROUGH AND THERE COULD BE SOME LAKE BREEZE CONVECTION
IN THE AFTERNOON AND EARLY EVENING AS WELL WHICH WOULD JUSTIFY AT
LEAST SLIGHT CHANCE POPS IN FOR MOST AREAS.

IN THE EXTENDED...ECMWF AND GFS SHOW A 500 MB RIDGE OVER THE UPPER
GREAT LAKES 12Z SUN WITH A TROUGH ACROSS THE WESTERN HALF OF THE
U.S. THE RIDGE GETS PUSHED FURTHER TO THE EAST BY THE TROUGH 12Z MON
WITH A SFC FRONT MOVING THROUGH THE U.P. BY 12Z TUE...THE RIDGE IS
PUSHED OVER TO THE ERN U.S. WITH TROUGHING INTO THE UPPER GREAT
LAKES LAGGING BACK INTO THE ROCKIES. THIS TROUGH REMAINS OVER THE
UPPER GREAT LAKES INTO WED. ABOVE NORMAL TEMPERATURES WILL SLOWLY
COOL BACK TOWARDS NORMAL BY THE END OF THIS FORECAST PERIOD AND IT
WILL REMAIN UNSETTLED WITH CHANCES OR SLIGHT CHANCES FOR RAIN.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 125 AM EDT THU AUG 21 2014

AN UPPER LEVEL LOW SPINNING NORTH OF LAKE HURON WILL SLOWLY MOVE
EAST LATE TONIGHT INTO THURSDAY. ABUNDANT LOW LEVEL MOISTURE
ROTATING AROUND THE LOW SHOULD PRODUCE LIFR TO VLIFR CONDITIONS
OVERNIGHT AT THE TAF SITES.

EXPECT SLOW IMPROVEMENT OF CONDITIONS TO MVFR BY LATE MORNING AND TO
VFR BY EARLY THU AFTERNOON WITH COMBINATION OF DIURNAL HEATING AND
LOW CONTINUING TO MOVE EAST OF THE REGION. BROUGHT -RA AND MVFR CIGS
INTO KIWD BY 22Z AND INTO KCMX AT 03Z THU. BROUGHT CIGS BACK DOWN TO
MVFR AT KSAW BY LATE THU EVENING IN UPSLOPE SE FLOW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 344 PM EDT WED AUG 20 2014

OVERALL...RELATIVELY WEAK PRESSURE GRADIENTS WILL KEEP WINDS BELOW
20 KNOTS THROUGH THIS WEEKEND. THE STRONGEST WINDS WILL OCCUR OVER
THE WESTERN THIRD OF LAKE SUPERIOR ON THURSDAY AND THURSDAY
EVENING WHEN NORTHEAST WINDS WILL FOCUS ALONG THE WESTERN
SHORELINE. IN ADDITION...PATCHY TO AREAS OF FOG WILL OCCUR OVER
PORTIONS OF LAKE SUPERIOR THROUGH THE UPCOMING WEEKEND. SHIP OBS
AND WEBCAMS INDICATE DENSE FOG OVER PORTIONS OF CENTRAL/EASTERN
LAKE SUPERIOR AND HAVE EXTENDED THE DENSE FOG ADVISORY INTO THE
EVENING. THIS MAY NEED TO BE EXTENDED FURTHER DEPENDING ON THE
EVOLUTION AND OBSERVATIONS THIS EVENING. ADDITIONAL MOISTURE WILL
SURGE NORTH THURSDAY AFTERNOON AND REMAIN THROUGH SUNDAY...PRODUCING
ADDITIONAL OPPORTUNITIES FOR FOG OVER LAKE SUPERIOR.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR LSZ243-244-
     249>251-264-266-267.

LAKE MICHIGAN...
NONE.
&&

$$

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





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