Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 261933
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
333 PM EDT FRI SEP 26 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM EDT FRI SEP 26 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS DATA SHOW AN UPPER RIDGE OVER
MUCH OF THE CENTRAL CONUS WHILE A DEEP UPPER TROUGH IS COMING ON
SHORE OVER THE WESTERN COAST OF THE CONUS. UNDER THE UPPER
RIDGE...THE REMNANTS OF THE UPPER LEVEL DISTURBANCE THAT AFFECTED
THE AREA 24 HOURS AGO IS SPINNING OVER THE MID MISSISSIPPI VALLEY.
AT THE SURFACE...A 1026MB HIGH IS STATIONARY OVER THE LOWER GREAT
LAKES AND STRETCHES A 1023MB RIDGE OVER THE UPPER GREAT LAKES
REGION. THIS RIDGE IS PROVIDING A SIGNIFICANT AMOUNT OF DRY AIR
BETWEEN 850-500MB AS SEEN ON THE 00Z KGRB/KAPX SOUNDINGS. THIS HAS
LED TO CLEAR SKIES OVER MUCH OF UPPER MICHIGAN EARLY THIS
MORNING...BUT SOME LINGERING LOW LEVEL MOISTURE REMAINS ON THE
NORTHWEST EDGE OF THE SURFACE RIDGE OVER NORTHERN LAKE SUEPRIOR AND
NORTHWEST ONTARIO. THESE CLOUDS HAVE BEEN GRADUALLY DISSIPATING
UNDER THE SUBSIDENCE ALOFT AND THE INFLUX OF DRIER AIR FROM THE
SOUTH-SOUTHWEST FLOW BETWEEN 925-850MB AND EXPECT THAT TO CONTINUE
THROUGH THE DAY TODAY. BACK TO UPPER MICHIGAN...THE CLEAR SKIES AND
LIGHT WINDS HAS LED TO PATCHY RADIATIONAL FOG TO DEVELOP OVER
PARTS OF THE CENTRAL/EASTERN U.P. AREAS NEAR LAKE MICHIGAN HAVE BEEN
SEEN FOG AS LOW AS 1/4MI THUS FAR AND EXPECT THAT AREA OF LOWER
VISIBILITIES TO EXPAND THROUGH SUNRISE. WILL MONITOR FOG TRENDS
AND IF THE LOWER VISIBILITIES BECOME MORE WIDESPREAD WILL ISSUE AN
SPS TO ADDRESS THE REDUCED VISIBILITIES INTO THE MORNING HOURS.
EXPECT THE FOG TO BURN OFF BETWEEN 14-15Z BASED OFF TIMING FROM A
COUPLE DAYS AGO AND GOES-R CLOUD THICKNESS DATA NEARING 900FT OVER
THE EAST LEADING TO A DISSIPATION TIME OF 2-2.5HRS AFTER SUNRISE.

AFTER THE FOG BURNS OFF...IT SHOULD BE A WONDERFULL EARLY FALL DAY
TO TAKE IN THE FALL COLORS. EXPECT SUNNY SKIES OVER MUCH OF THE
AREA...ALTHOUGH WITH THE NORTHWEST THIRD STILL NEAR SOME OF THE
DEPARTING 925-850MB MOISTURE WOULD EXPECT SOME DIURNAL CU TO
DEVELOP IN THAT AREA DURING PEAK HEATING. WITH PLENTY OF SUNSHINE
AND MIXING TO AROUND 875MB...EXPECT MOST AREAS TO BE IN THE MID 70S
FOR HIGHS TODAY. LIGHT SOUTHERLY FLOW WILL LEAD TO SLIGHTLY COOLER
VALUES NEAR LAKE MICHIGAN AND SLIGHTLY WARMER VALUES IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR.

WITH THE UPPER/SURFACE RIDGE NEARLY STATIONARY OVER THE AREA FOR
THE NEXT 24HRS...EXPECT FOG TO MAKE AN APPEARANCE ACROSS THE AREA
AGAIN TONIGHT. COVERAGE WILL LIKELY BE SIMILAR ACROSS THE
AREA...WITH THE LOWEST VISIBILITIES OVER THE CENTRAL/EAST AND
ESPECIALLY NEAR LAKE MICHIGAN.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM EDT FRI SEP 26 2014

THE RELATIVELY WARM STREAK SEEN OVER THE PAST WEEK WILL COME TO AN
END EARLY NEXT WEEK AS A MORE PROGRESSIVE PATTERN DEVELOPS OVER THE
CENTRAL U.S.

SATURDAY NIGHT...WEAK MID-LEVEL RIDGING WILL BE OVER THE REGION AT
THE BEGINNING OF THE PERIOD AS A SLOW MOVING COLD FRONT STRETCHES
FROM NORTH DAKOTA TO HUDSON BAY. THIS FRONT WILL BE THE MAIN PLAYER
IN PRECIP CHANCES EARLY NEXT WEEK.

WITH THE LIGHT SOUTHERLY FLOW AND A CONTINUED INCREASE OF SFC
MOISTURE SATURDAY NIGHT...FOG WILL BE POSSIBLE ONCE AGAIN ACROSS THE
INTERIOR CENTRAL AND EAST. HOWEVER...DAYTIME MIXING ON SATURDAY MAY
LOWER DEWPOINTS FARTHER THAN MODELS ARE INDICATING. THIS LIKELY WILL
NOT BE REALIZED UNTIL SATURDAY AFTERNOON...SO WILL CONTINUE WITH THE
MENTION OF AREAS OF FOG.

SUNDAY...THE COLD FRONT WILL INCH CLOSER TO THE REGION ON
SUNDAY...BUT SHOULD HOLD OFF REACHING THE KEWEENAW UNTIL SUNDAY
EVENING. SUNDAY WILL BE THE LAST DAY IN THIS WARM STRETCH. WITH 850
HPA TEMPS STILL 12 TO 14C ACROSS THE CWA...HIGHS WILL BE WELL INTO
THE 70S FOR MUCH OF THE AREA. THESE VALUES ARE 15-20F ABOVE AVERAGES
IN THE LOW 60S THIS TIME OF YEAR. SEVERAL MODELS ARE INDICATING SOME
AFTERNOON DIURNAL SHOWERS ALONG THE LAKE BREEZE NORTH-CENTRAL. AM
STILL HAVING A HARD TIME BUYING INTO THIS AS LOW-LEVEL MOISTURE
APPEARS TO BE OVERDONE BY THE MODELS AND DEEP-LAYER MOISTURE IS
MARGINAL. DAYTIME MIXING ALONG WITH QUICKLY DIMINISHING
EVAPOTRANSPIRATION THIS TIME OF YEAR SHOULD LIMIT THE OVERALL SFC
MOISTURE AND INSTABILITY.

SUNDAY NIGHT AND MONDAY...THE COLD FRONT WILL ARRIVE ACROSS
THE KEWEENAW EARLY SUNDAY EVENING AND CONTINUE SINKING SOUTHWARD
THROUGH THE NIGHT. A DECENT AMOUNT OF LINEAR FORCING WILL BE
AVAILABLE THROUGH LOW-LEVEL FGEN...MID-LEVEL Q-VECTOR CONV...AND THE
RIGHT ENTRANCE OF AN UPPER JET. THIS SUGGESTS CONTINUING WITH LIKELY
POPS FOR MUCH OF THE AREA. TIMING OF THE PRECIP REMAINS A
SIGNIFICANT CHALLENGE DUE TO MODEL DIFFERENCE AND INCONSISTENCY. THE
12Z NAM SOLUTION HAS COME IN MUCH DIFFERENT FROM PREVIOUS RUNS AND
OTHER MODELS. THE SLOWER PROGRESSION OF THE TROUGH BY THE NAM DELAYS
PRECIP UNTIL LATE SUNDAY NIGHT. WITH THAT SAID MONDAYS FORECAST
BECOMES QUITE TRICKY AS THE TEMP AND PRECIP FORECAST HINGES ON HOW
FAR SOUTH THE FRONT MAKES IT SUNDAY NIGHT. A FASTER SOLUTION /ECMWF/
WOULD RESULT IN A MUCH COOLER DAY WITH SHOWERS FOR THE ENTIRE CWA. A
SLOWER SOLUTION /NAM/ WOULD ALLOW DIABATIC HEATING ACROSS THE
SOUTH-CENTRAL TO STALL THE FRONT EVEN MORE...BRINGING MUCH COOLER
CONDITIONS AND SHOWERS TO JUST THE NORTHERN CWA. HAVE OPTED TO TREND
TOWARD THE SLOWER IDEA AS EVEN THE 12Z GFS SLOWED THE PROGRESSION OF
THE FRONT. OVERALL...CONFIDENCE IS FAIRLY HIGH ON THE LIKELIHOOD OF
RAIN...BUT LOW ON THE TIMING.

MONDAY NIGHT AND TUESDAY...MID-LEVEL RIDGING WILL BEGIN BUILDING
ACROSS THE UPPER GREAT LAKES MONDAY NIGHT AS THE SFC FRONT CONTINUES
SSE OUT OF THE AREA. LOW-LEVEL MOISTURE WILL LINGER WELL INTO
TUESDAY WITH WEAK NE FLOW OFF LAKE SUPERIOR. THIS SHOULD LEAD TO AT
LEAST SOME UPSLOPE SHOWERS/DRIZZLE CENTRAL AND EAST ALONG LAKE
SUPERIOR THROUGH MONDAY NIGHT. THEN...AN INVERSION AROUND 3KFT
COMBINED WITH THE WEAKENING IMPACT OF THE SUN FOR MIXING...MAY KEEP
THE AREA SOCKED IN WITH LOW CLOUDS THROUGHOUT THE DAY TUESDAY. HAVE
THUS CONTINUED THE TREND OF LOWERING HIGH TEMPS FOR TUESDAY...WITH
HIGHS GENERALLY IN THE 50S CWA-WIDE. ALSO...WITH LOW-LEVEL HIGH
PRESSURE SHIFTING EASTWARD NORTH OF LAKE SUPERIOR AND INITIATING
RETURN SOUTHERLY FLOW ACROSS THE AREA...IT MAY EVEN BE DIFFICULT TO
COMPLETELY RID THE AREA OF LOW CLOUDS BY TUESDAY NIGHT.

WEDNESDAY THROUGH FRIDAY...DEEP TROUGHING OVER THE NORTHERN ROCKIES
WILL BE LIFTING NORTHEASTWARD AS MID-LEVEL RIDGING OVER THE UPPER
GREAT LAKES SHIFTS EASTWARD. MODEL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT WITH THE SYNOPTIC PATTERN...BUT DIFFERS SOMEWHAT WITH THE
OVERALL INTENSITY OF THE TROUGH AND ASSOCIATED SFC LOW. ATTM...A
COLD FRONT IS PROGGED TO SLOWLY TRACK EASTWARD ACROSS THE CWA
WEDNESDAY MORNING THROUGH THURSDAY NIGHT AS THE SFC LOW MOVES
NORTHWARD OVER MANITOBA. WILL MAINTAIN CONSENSUS POPS...WITH AN
EMPHASIS FOR BETTER CHANCES ON THURSDAY WITH THE ARRIVAL OF
UPPER-LEVEL SUPPORT FROM THE RIGHT ENTRANCE OF A JET.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 130 PM EDT FRI SEP 26 2014

WITH PLENTY OF DRY AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE OVER
THE UPPER GREAT LAKES...EXPECT VFR CONDITIONS AND GENERALLY LIGHT
WINDS AT ALL SITES. KCMX SHOULD SEE AN EASTERLY LAKE BREEZE AFFECT THE
SITE IN THE AFTERNOON. FOG IS POSSIBLE AT ALL THREE SITES AGAIN
TONIGHT...WITH THE GREATEST CHANCE OF MVFR VSBY OR LOWER AT
KSAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 AM EDT FRI SEP 26 2014

A HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WILL REMAIN
STATIONARY THROUGH SUNDAY WHILE STRETCHING A RIDGE NORTHWEST ACROSS
THE UPPER GREAT LAKES. THIS WILL LEAD TO LIGHT SOUTHERLY FLOW
(BELOW 20KTS) INTO SUNDAY. A COLD FRONT DROPPING SOUTHEAST ACROSS
THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY MORNING WILL SHIFT
WINDS AROUND TO THE NORTHEAST WITH GUSTS TO 30KTS. THERE IS A
POTENTIAL FOR A FEW GALE FORCE GUSTS TO 35KTS LATE SUNDAY NIGHT
INTO MONDAY MORNING. HIGH PRESSURE CENTERED OVER EASTERN CANADA WILL
THEN PLACE A RIDGE OVER THE UPPER GREAT LAKES FOR MONDAY NIGHT AND
TUESDAY...LEADING TO DIMINISHING WINDS.

FINALLY...WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE
SUPERIOR...THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER
NORTHERN PORTIONS OF LAKE SUPERIOR OVER THE NEXT COUPLE OF DAYS.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KLUBER
AVIATION...JLB
MARINE...SRF





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