Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 190909
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
509 AM EDT SAT APR 19 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 428 PM EDT FRI APR 18 2014

A SHORTWAVE TROUGH IS CURRENTLY OVER THE NRN ROCKIES...WITH A
STRENGTHENING SFC LOW OVER MT/WY. ADDITIONALLY...THERE IS A WEAK
SHORTWAVE TROUGH AND 1031MB SFC HIGH OVER THE CWA. THE ROCKIES
SHORTWAVE WILL MOVE TO ECENTRAL MANITOBA/ECENTRAL ONTARIO BY 00Z
SUN.

CLEARING SKIES BEHIND THE WEAK SHORTWAVE OVERHEAD MAY ALLOW SOME FOG
TO DEVELOP OVER PORTIONS OF THE ERN HALF OF THE CWA. HIGH CLOUDS
MOVING INTO THE WRN CWA EARLIER TONIGHT WILL LIMIT FOG POTENTIAL
THERE.

PRECIP WILL MOVE INTO THE WRN CWA SAT MORNING AS STRONG FORCING FROM
ISENTROPIC ASCENT/WAA AND LOW-MID LEVEL MOISTURE ADVECTION. THE
MOISTURE TRANSPORT WILL BE NEEDED AS THE AIRMASS ABOVE THE NEAR SFC
INVERSION WILL BE QUITE DRY. THIS DRYNESS SHOULD HOLD THE PRECIP OFF
UNTIL AFTER 12Z OVER UPPER MI...WHICH ALLOWS FOR WARMER AIR TO MOVE
IN...MAKING RAIN THE DOMINANT PTYPE ON SAT. DO HAVE SOME SNOW EARLY
OVER THE KEWEENAW...BUT WOULD NOT BE SURPRISED TO NOT SEE ANY PRECIP
UNTIL LOW-MID LEVEL TEMPS WARM ENOUGH FOR ALL RAIN. ANOTHER AREA OF
MIXED PRECIP IS OVER FAR WRN UPPER MI WHERE THE RAIN WILL START
BEFORE SFC TEMPS ARE ABOVE FREEZING...SOME SOME VERY MINOR FREEZING
RAIN ACCUMULATIONS ARE POSSIBLE THERE EARLY. AS FAR AS PRECIP
AMOUNTS...HAVE NO QPF SCENTRAL AND E...WITH UP TO 0.40 INCHES OVER
THE KEWEENAW ON SAT. THE PRECIP MOVES SE ACROSS THE REST OF THE CWA
SAT NIGHT INTO SUN...SEE THE LONG TERM DISCUSSION FOR THE DETAILS OF
THAT TIME FRAME.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 428 AM EDT SAT APR 19 2014

MAIN FCST CONCERN IN THE LONGER TERM IS FOCUSED ON THE POTENTIAL
INTERACTION BTWN A STALLED FNT/RIBBON OF HIER MSTR JUST S OF UPR MI
AND A SHRTWV THAT IS FCST TO MOVE E ACRS SRN CANADA ON MON AND IF/
HOW MUCH RA WL FALL OVER UPR MI AND IMPACT AREA STREAMS/HYDRO.
CONFIDENCE IN THIS FCST IS LOWERED BY POOR MODEL AGREEMENT ON THE
INTERACTION BTWN THESE FEATURES.

SUN...AS SHRTWV/SFC LO OVER NW ONTARIO ON SUN MRNG MOVE E CLOSER TO
JAMES BAY BY LATE IN THE DAY...A SHRTWV RDG AND MID LVL DRYING ARE
FCST TO ADVANCE INTO THE UPR LKS BEHIND DEPARTING/WEAKENING
ATTENDANT COOL FNT AND WARM CONVEYOR BELT MSTR RIBBON. ALTHOUGH SOME
MODEL DIFFERENCES REMAIN ON HOW AGGRESSIVE THIS MID LVL DRYING WL
BE...THE PREVIOUSLY SLOWER CNDN MODEL SHOWS ENUF DRYING TO END THE
PCPN OVER ALL BUT THE FAR SE CWA BY 00Z. OPTED TO RETAIN FLAVOR OF
GOING FCST THAT SHOWS LINGERING POPS OVER THE SE HALF DIMINISHING
THRU THE DAY...AND ENDING OVER ALL BUT THE FAR SE BY 00Z MON.
OTRW...WITH DIURNAL HEATING...EXPECT LO CLDS/FOG OVER THE MELTING SN
PACK TO DSPT BY THE AFTN. H85 TEMPS IN THE 6-8C RANGE WL SUPPORT ABV
NORMAL TEMPS...BUT LGT WINDS ASSOCIATED WITH WEAK HI PRES UNDER THE
SHRTWV RDGING SHOULD ALLOW FOR LK BREEZES THAT WL BRING LOCAL
COOLING NEAR THE SHORES.

SUN NGT/MON...SUN NGT WL START DRY EXCEPT PERHAPS OVER THE FAR
SCENTRAL CLOSER TO LINGERING STNRY FNT/MSTR AXIS. BUT AS NEXT SHRTWV
MOVING ESEWD ACRS SCENTRAL CAN IN THE NW FLOW E OF BLDG RDG OVER WRN
CANADA APRCHS AND GENERATES SOME HGT FALLS OVER THE UPR LKS...SOME
OF THE MODELS...ESPECIALLY THE 00Z ECWMF/UKMET...SHOW DEEP MSTR TO
THE S EXPANDING BACK TO THE N LATE SUN NGT AND IMPACTING MAINLY THE
SCENTRAL AND E. THE NCEP MODELS ARE MUCH DRIER AND INDICATE MAINLY
SCT RA SHOWERS ASSOCIATED WITH THE PASSAGE OF THE INCOMING SHRTWV.
THE 00Z CNDN MODEL SHOWS THE PCPN EXPANDING BACK FARTHER TO THE N
BUT NOT UNTIL MON. WHILE THE BLDG RDG OVER THE SE CONUS SUPPORTS THE
FARTHER N SCENARIO FAVORED BY THE NON NCEP MODELS...THE RATHER LARGE
SEPARATION BTWN THE DISTURBANCES IN QUESTION AND ABSENCE OF A SGNFT
BACKING OF THE UPR LVL WINDS TO A MORE SW DIRECTION INDICATE THE
DRIER NCEP GUIDANCE IS ON THE RIGHT TRACK. THE MODELS TYPICALLY HAVE
A DIFFICULT TIME HANDLING INTERACTION/PHASING BTWN DISPARATE
DISTURBANCES...SO CONFIDENCE IS LO IN THIS PORTION OF THE FCST.
FORTUNATELY...EVEN THE WETTER SCENARIO FAVORED BY THE NON NCEP
MODELS POINTS TO HEAVIER RA OVER THE SCENTRAL AND ERN CWA...WHERE
LESS SN REMAINS. OTRW...MAINTAINED MENTION OF PATCHY FOG LATE SUN
NGT INTO MON MRNG WITH LGT WINDS/POTENTIAL FOR DRIER MID LVLS OVER
MELTING SN.

MON NGT...INCRSG NNW FLOW WITH H925 WINDS INCRSG UP TO 25-30 KTS
ASSOCIATED WITH DIGGING SHRTWV THRU THE GREAT LKS IS FCST TO DROP
H85 TEMPS AS LO AS -6 TO -7C BY 12Z TUE. WHILE THE INCOMING AIRMASS
IS NOT COLD ENUF FOR LK EFFECT SN...SOME OF THE MODELS SHOW ENUF
LLVL MSTR TO JUSTIFY CHC POPS. WITH THE ARRIVAL OF THE COLDER AIR...
EXPECT THE RA SHOWERS TO MIX WITH OR CHG TO SN...ESPECIALLY OVER THE
HIER TERRAIN OF THE W.

TUE INTO WED...CNDN SFC HI PRES RDG UNDER UPR RDG TRAILING DEPARTING
SHRTWV WL BRING A PERIOD OF COOLER AND DRIER WX TO THE CWA.

EXTENDED...NOT SURPRISINGLY...THERE REMAINS SGNFT DISAGREEMENT AMONG
THE LONGER RANGE MODELS ON THE HANDLING OF NEXT LO PRES THAT IS
LIKELY TO IMPACT THE UPR LKS LATER ON WED INTO FRI. THE 00Z ECMWF
INDICATES A COLDER SCENARIO WITH THE SFC LO PRES TRACKING TO THE S
OF UPR MI AND BLDG HI PRES JUST N OF LK WINNIPEG. THIS FCST WOULD
RESULT IN SOME MIXED PCPN AT THE ONSET AND LATER IN THE WEEK. THE
00Z GFS AND CNDN MODELS ON THE OTHER HAND SHOW A DEEPER LO FARTHER
TO THE N ALONG WITH A STRONGER SLY FLOW OF WARMER AIR. WL RELY ON
MODEL CONSENSUS FOR NOW.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1215 AM EDT SAT APR 19 2014

VFR CONDITIONS ARE EXPECTED AT KIWD/KCMX THRU THE NIGHT WITH ONLY
HIGH AND MID CLOUDS INCREASING OVER DRY LOW-LEVEL AIR MASS. AT
KSAW...RADIATIONAL COOLING MAY BE SUFFICIENT BEFORE HIGHER CLOUDS
ARRIVE TO RESULT IN FOG/MVFR VIS. ALTHOUGH MOISTURE ALOFT CONTINUES
TO INCREASE TODAY...LINGERING DRY LOW-LEVELS MAKES PCPN FCST LESS
CERTAIN. BEST CHC OF DRY LOW-LEVELS GIVING WAY IS AT KCMX. SOME SHRA
ARE EXPECTED THERE IN THE AFTN. SPRINKLES MAY AFFECT KIWD. BETTER
CHC OF SHRA WILL OCCUR LATE AFTN AT KIWD/KCMX AND IN THE EVENING AT
KSAW. VFR CONDITIONS SHOULD GENERALLY CONTINUE...THOUGH KCMX MAY
FALL TO MVFR WITH SOMEWHAT HEAVIER SHRA EXPECTED THERE.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT FRI APR 18 2014

WINDS GENERALLY BELOW 20 KTS THROUGH THE ENTIRE FORECAST PERIOD. ONLY
EXCEPTION WILL BE SATURDAY AND SATURDAY NIGHT AS EAST TO SOUTHEAST
WINDS INCREASE TO 20 TO 30 KTS ON FLANK OF LOW PRESSURE MOVING FROM
NORTHERN PLAINS INTO NORTHERN ONTARIO.
&&

.HYDROLOGY...
ISSUED AT 507 AM EDT SAT APR 19 2014

AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS...THE RECENT HEAVY
SNOWFALL ACROSS WESTERN UPPER MI HAS REPLENISHED SOME OF THE WATER
CONTENT THAT WAS LOST DURING THE WARMER CONDITIONS OVER THE PAST TWO
WEEKS. THE WESTERN HIGH TERRAIN NOW HAS 6 TO 8 INCHES OF WATER
EQUIVALENT...WITH LOCALIZED 10 INCH AMOUNTS. SINCE TEMPERATURES ARE
EXPECTED TO BE AT OR SLIGHTLY ABOVE AVERAGE ACROSS UPPER MI THIS
WEEKEND INTO MON /THE UPPER 50S AND LOW 60S AWAY FROM LOCAL LAKE
COOLING ON SUN AND MON/ WITH DEWPTS RISING AS HI AS THE LO 40S...A
GOOD DEAL OF MELTING SHOULD OCCUR. EXCEPT FOR TONIGHT...LO TEMPS WILL
FALL TO AT LEAST NEAR FREEZING...LIMITING CONCERNS OF RAPID MELTING.
COOLER AIR WILL RETURN MON NIGHT INTO THU...SOMEWHAT MODERATING THE
MELT DOWN. HIGHS ARE STILL EXPECTED TO RANGE FROM THE 40S TO THE LOW
50S.

AS FOR PRECIPITATION...AN ADDITIONAL 0.25 TO 0.75 INCH OF LIQUID IN
THE FORM OF MOSTLY RAIN IS EXPECTED THIS AFTERNOON INTO EARLY SUN
AFTERNOON. FORTUNATELY...THE HEAVIER RAIN IS FORECAST OVER THE EAST
WHERE THERE IS GENERALLY LESS SNOW ON THE GROUND. BUT WITH THE
ADDITIONAL LIQUID ADDED TO THE SNOWPACK FROM THE RECENT SNOW
STORM...WARM TEMPERATURES/GREATER SN MELT...AND LIGHT TO MODERATE
RAINFALL...A PROLONGED PERIOD OF HIGHER RIVER FLOWS ARE EXPECTED.

THOUGH WIDESPREAD FLOODING IS NOT A CONCERN AT THIS TIME...REMAINING
ICE ON THE RIVERS COULD LEAD TO POTENTIAL ICE JAMS ONCE THE WARMER
AIR ARRIVES THRU MON. THOSE LIVING AROUND RIVERS...CREEKS...AND
STREAMS SHOULD MONITOR BOTH RIVER LEVELS AND ICE CONDITIONS. ICE
JAMS CAN FORM AND BREAK QUICKLY...RESULTING IN RAPIDLY FLUCTUATING
RIVER LEVELS.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...KC
AVIATION...ROLFSON
MARINE...TITUS
HYDROLOGY...KC




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