Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 221945
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
345 PM EDT WED APR 22 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 344 PM EDT WED APR 22 2015

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO/
POCKET OF H5 TEMPS NEAR -30C CENTERED OVER ONTARIO TO THE SW OF
JAMES BAY DOWNSTREAM OF HI AMPLITUDE RDG OVER THE ROCKIES. DEEP
MOIST CYC NW FLOW ARND THE CLOSED LO CONTINUES TO IMPACT UPR MI...
DRAWING UNSEASONABLY CHILLY AIR /H85 TEMPS AS LO AS -12 TO -14C THAT
ARE SUFFICIENTLY COLD FOR LES/ INTO THE AREA. THE RESULT HAS BEEN
NMRS SN SHOWERS THAT HAVE BEEN EXACERBATED OVER LAND WITH DAYTIME
HEATING EVEN IN THE ABSENCE OF SGNFT LARGER SCALE FORCING/DEEP LYR
QVECTOR CNVGC.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/SN AMOUNTS
ESPECIALLY TNGT AS UPR LO DRIFTS SLOWLY TO THE E. TEMPS WL REMAIN
BLO NORMAL THRU THU.

TNGT...UPR LO IS FCST TO DRIFT SLOWLY TO THE E...ALLOWING FOR SLOWLY
RISING H5 HGT/WEAKENING LLVL CYC FLOW. ALTHOUGH SOME GENERAL LARGER
SCALE SUBSIDENCE IS FCST TO DOMINATE...H85 TEMPS REMAINING AS LO AS
ABOUT -13C IN THE PRESENCE OF SOME LINGERNING DEEP MSTR/NOCTURNAL
COOLING WL BE SUFFICIENT TO MAINTAIN LES IN THE FAVORED NW WIND SN
BELTS OVER THE ERN CWA. EXPECT UP TO A COUPLE INCHES OF SN ACCUM IN
THIS AREA. OVER THE W...WARMING H85 TEMPS TO ARND -10C/ LOWERING
SUBSIDENCE INVRN UNDER THE GREATER HGT RISES SHOULD TEND TO CAUSE
THE SN SHOWERS TO DIMINISH IN THAT AREA. HOWEVER...THE PERSISTENT
UPSLOPE NW FLOW AND LINGERING UPSLOPE FLOW WL ALLOW FOR AT LEAST
SOME SCT SN SHOWERS EVEN IN THAT AREA.

THU...PERSISTENT HGT RISES AND SUBSIDENCE/TENDENCY FOR THE LLVL FLOW
TO BECOME MORE ACYC AS WELL AS SOME LLVL DRYING IN THE PRESENCE OF
DAYTIME HEATING WL DIMINISH THE SN SHOWERS W-E. FCST SDNGS INDICATE
THERE WL BE SOME SUNSHINE IN THE AFTN AS WELL WITH HI PRES RDG FCST
TO BLD INTO THE WRN CWA LATER IN THE DAY. TEMPS SHOULD REBOUND INTO
THE 40S OVER THE INTERIOR W AND SCENTRAL AWAY FM LK MODERATION WITH
H85 TEMPS PROGGED TO REACH NEAR -6C ALONG THE WI BORDER BY 00Z FRI.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 302 AM EDT WED APR 22 2015

NAM SHOWS A TROUGH OVER THE EASTERN U.S. 12Z THU WITH MORE TROUGHING
ACROSS THE WEST COAST AND A SHORTWAVE RIDGE OVER THE PLAINS. NAM
SHOWS SOME WEAK 850-500 MB Q-VECTOR CONVERGENCE MOVING THROUGH THE
CWA ON THU WITH MOISTURE MOVING OUT IN THE AFTERNOON. AS THE
SHORTWAVE RIDGE MOVES TOWARDS THE AREA AND A TROUGH OVER THE EASTERN
U.S. MOVES AWAY...THE WRAPAROUND LAKE ENHANCED PCPN WILL SLOWLY WIND
DOWN AND HAVE IT DRYING OUT FRI AND FRI NIGHT WITH SLOWLY
DIMINISHING POPS IN THE CENTRAL AND EAST ON THU INTO THU NIGHT.
OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES OR POPS.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB LOW OVER THE CENTRAL
PLAINS 12Z SAT WITH MORE TROUGHING IN THE WESTERN U.S. THE 500 MB
LOW AND TROUGH IN THE CENTRAL PLAINS GETS SHEARED OUT BY 12Z SUN AND
IS REPLACED BY A SHORTWAVE RIDGE THAT MOVES INTO THE UPPER GREAT
LAKES. THE RIDGE REMAINS OVER THE UPPER GREAT LAKES ON MON WITH
TROUGHING MOVING INTO THE NORTHERN PLAINS. THIS TROUGHING MOVES INTO
THE UPPER GREAT LAKES 12Z TUE. TEMPERATURES WILL STAY BELOW NORMAL
THIS FORECAST PERIOD. WILL CONTINUE WITH DRY WEATHER SAT THROUGH SUN
NIGHT AND THEN GO WITH SLIGHT CHANCE POPS MON THROUGH TUE AS A SFC
FRONT IS WELL OFF TO THE WEST AT THAT TIME AND PRODUCES SOME OVER
RUNNING PCPN THAT IS OFF TO THE WEST MOSTLY.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 729 AM EDT WED APR 22 2015

SPOTTY SNOW SHOWERS IN PERSISTENT NW FLOW HAS RESULTED IN VARIABLE
CONDITIONS RANGING MAINLY FROM MVFR TO IFR...WITH THE TEMPORARY VFR
CEILINGS AND VIS IN BETWEEN SNOW SHOWERS. DUE TO THE HIGHLY VARIABLE
REGIME...TEMPO GROUPS WILL REMAIN NECESSARY. EXPECT IMPROVING
CONDITIONS DURING THE DAYTIME HOURS WITH THE ASSISTANCE OF THE LATE
APRIL SUN...WITH CEILINGS IMPROVING A CATEGORY /MAINLY TO MVFR...IF
NOT VFR AT SAW IN THE LESS FAVORABLE NW FLOW/. THE SFC LOW OVER
JAMES BAY THIS MORNING WILL SLOWLY WEAKEN...AND A STRONG RIDGE OF
HIGH PRESSURE ACROSS N AND CENTRAL CANADA WILL BE BUILDING A RIDGE
CLOSER TO THE AREA. LOOK FOR IMPROVING CONDITIONS W TO E LATER
TONIGHT AS DRIER AIR NEARS. MVFR TO VFR CEILINGS/VIS ARE ANTICIPATED
AT IWD AROUND 12Z.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 AM EDT WED APR 22 2015

A FEW NW WINDS GUSTING TO 30 TO NEAR 35KT GALES WILL REMAIN POSSIBLE
OVER N AND CENTRAL LAKE SUPERIOR TODAY. LOW PRESSURE ACROSS JAMES
BAY WILL FILL LATE TONIGHT AND THURSDAY. THE TROUGH ACROSS LAKE
SUPERIOR THIS MORNING...EXTENDING FROM THE JAMES BAY LOW...WILL
SLOWLY BE REPLACED BY A RIDGE. THIS RIDGE WILL REMAIN IN PLACE FROM
FRIDAY THROUGH SUNDAY...EXTENDING FROM STRONG HIGH OVER FAR NORTHERN
CANADA AND GREENLAND.
&&

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

$$

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


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