Prognostic Meteorological Discussion
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FXUS02 KWBC 061545
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1044 AM EST FRI MAR 06 2015

VALID 12Z MON MAR 09 2015 - 12Z FRI MAR 13 2015

...OVERVIEW...

WHILE FLOW WILL STEADILY EVOLVE ON A DAILY BASIS THE MOST
PROMINENT FEATURES FROM THE MULTI-DAY MEAN PERSPECTIVE SHOULD BE
FAIRLY STABLE.  THESE FEATURES INCLUDE AN E-CNTRL PAC TROUGH...
WEST COAST RIDGE... BROAD TROUGHING OVER ERN CANADA INTO THE
GRTLKS/NORTHEAST... AND THEN OVER MORE SRN LATITUDES A TROUGH OVER
THE SRN ROCKIES/PLAINS INTO MEXICO AND RIDGE CENTERED E OF THE
BAHAMAS.  WITH GFS RUNS SINCE 12Z YDAY HAVING ADJUSTED TO
CONSENSUS WITH NRN STREAM FLOW AND GUIDANCE CONVERGING WITH THE
EVOLUTION OF THE ERN PAC UPR LOW INITIALLY NEAR 150W... CLUSTERING
IS BETTER TODAY AS TYPICAL DETAIL ISSUES PROVIDE THE MAIN
UNCERTAINTY.


...GUIDANCE EVALUATION AND PREFERENCES...

FROM DAY 3 MON INTO DAY 5 WED A CONSENSUS BLEND OF THE 06Z GFS/00Z
NAEFS MEAN AND 00Z ECMWF/ECMWF MEAN PROVIDES A REASONABLE FCST.
THROUGH AT LEAST DAY 5 THE 06Z GFS IS PREFERABLE TO THE 00Z
VERSION THAT SHOWS LOWER HGTS OVER PORTIONS OF THE NRN/ERN CONUS
VERSUS MOST OTHER SOLNS.  ALSO THE GEFS MEANS ARE A TAD FASTER
THAN THE MAJORITY CLUSTER WITH SFC LOW PRES TRACKING ACROSS
CNTRL-ERN CANADA.  THERE IS GOOD AGREEMENT WITH THE SYSTEM WELL
OFFSHORE THE WEST COAST... WITH MODELS/ENSMEANS MORE SIMILAR THAN
IN PREVIOUS DAYS.  SOME SPREAD AND RUN TO RUN VARIABILITY ARE
NOTED WITH DETAILS OF THE WAVY FRONT FROM THE GULF OF MEXICO INTO
THE WRN ATLC.  LATEST GFS/ECMWF RUNS AND SOMEWHAT LESS DEFINED
ENSEMBLE MEANS PROVIDE A GOOD INTERMEDIATE FCST.

BY DAYS 6-7 THU-FRI SHRTWV UNCERTAINTIES PLAY A GREATER ROLE IN
THE FCST FAVORING A 50/30/20 BLEND OF THE 00Z ECMWF MEAN/00Z NAEFS
MEAN/06Z GEFS MEAN TO CAPTURE THE LARGER SCALE SIMILARITIES OF
LATEST GUIDANCE.  AS OF THU LATEST OPERATIONAL RUNS HAVE ADJUSTED
TO THE ENSEMBLE MEAN IDEA OF QUICKER EJECTION OF THE INITIAL ERN
PAC UPR LOW IN RESPONSE TO UPSTREAM TROUGHING.  IN VARYING WAYS
MOST SOLNS SUGGEST WHAT ENERGY REACHES THE WRN CONUS SHOULD
ULTIMATELY SPLIT BTWN THE PROGRESSIVE NRN STREAM AND FEEDING INTO
THE SRN STREAM MEAN TROUGH.  EVEN IN ECMWF RUNS THAT HAVE BEEN
MORE SIMILAR TO CONSENSUS EARLIER IN THE PERIOD... NRN STREAM
DETAILS BECOME QUITE ERRATIC BY THIS TIME FRAME.


...SENSIBLE WEATHER HIGHLIGHTS...

GUIDANCE CONTINUES TO SHOW THE STRONGEST SIGNALS FOR HVY TO
EXCESSIVE RNFL NEAR THE CNTRL GULF COAST AND EXTENDING TO SOME
DEGREE NWD/NEWD... BTWN THE PERSISTENT SRN ROCKIES/PLAINS INTO
MEXICO TROUGH ALOFT AND DOWNSTREAM RIDGE.  THERE IS NOW MORE
AGREEMENT THAT ONE WAVE OF HEAVIER RNFL SHOULD PROGRESS NEWD FROM
THE W-CNTRL GULF COAST MON-TUE WITH SOME OF THIS ACTIVITY IN
LIGHTER FORM REACHING INTO THE SRN MID ATLC.  FOLLOWING A RELATIVE
BREAK THERE SHOULD BE ANOTHER PUSH OF MSTR NWD FROM THE CNTRL GULF
COAST MID-LATE WEEK WITH SOME UNCERTAINTY IN EXACT LONGITUDE OF
THIS AXIS OF MSTR.  NOTE THAT MANY AREAS FROM THE SRN HALF OF THE
MS VLY EWD/NEWD HAVE ALREADY RECEIVED SIGNIFICANT PCPN ACCUMS OVER
THE PAST TWO WEEKS.

MEANWHILE EJECTING ERN PAC ENERGY FILTERING THROUGH THE LONG TERM
WEST COAST MEAN RIDGE SHOULD SPREAD SOME PCPN INTO/THROUGH THE WRN
STATES PRIMARILY WED-THU AND BECOMING LIGHTER/MORE SCT FRI.  ONLY
IN THE LATEST CYCLE HAS GUIDANCE LOCKED ONTO A MORE AGREEABLE SOLN
FOR DETAILS ALOFT SO CONFIDENCE IN COVERAGE/INTENSITY AT
PARTICULAR LOCATIONS IS ONLY MODERATE AT BEST.  CURRENT CONSENSUS
WOULD YIELD A PRIMARY FOCUS OVER THE PAC NW AND EXTREME NRN
ROCKIES WITH HIGHEST TOTALS OVER VANCOUVER ISLAND.  AREAS FARTHER
S/SE WOULD SEE LIGHTER/MORE SCT ACTIVITY.

EXPECT CONSISTENTLY WARM TEMPS FROM THE WRN STATES THROUGH THE
NRN-CNTRL PLAINS/UPR MS VLY WITH DECENT COVERAGE OF PLUS 10-20F
ANOMALIES FOR HIGHS ON MOST DAYS.  CLOUDS/RNFL SHOULD KEEP DAYTIME
READINGS 10-20F BELOW NORMAL OVER THE SRN PLAINS/LWR MS VLY EARLY
NEXT WEEK BEFORE TEMPS TREND CLOSER TO NORMAL.  ERN CONUS TEMPS
SHOULD TREND FROM NEAR/SLIGHTLY BELOW NORMAL EARLY TO SOMEWHAT
ABOVE NORMAL MIDWEEK AND BACK TO BELOW NORMAL LATE.  SRN AREAS
SHOULD REMAIN WARM AT NIGHT GIVEN PERSISTENCE OF CLOUDS/MSTR.

RAUSCH

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