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FXUS10 KWNH 121653

PMDHMD

 

MODEL DIAGNOSTIC DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

1252 PM EDT THU MAR 12 2009

 

VALID MAR 12/1200 UTC THRU MAR 16/0000 UTC

 

...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR

INGEST...



12Z NAM/GFS/CANADIAN/UKMET EVALUATION INCLUDING PREFERENCES...



INITIALIZATION ERRORS IN THE NAM/GFS DO NOT APPEAR TO HAVE A

NEGATIVE IMPACT ON THEIR SHORT RANGE FORECASTS.



TROUGH MOVING INTO THE PACIFIC NORTHWEST SATURDAY MORNING...

THE NAM HAS TRENDED BROADER ALOFT AND SHOWS AN INTERMEDIATE TIMING

WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS.  THE GFS HAS TRENDED

NORTHWARD WITH THIS ENERGY OVER ITS PAST DAY OF RUNS.  THE ECMWF

HAS TRENDED WELL NORTHWARD/STRONGER WITH THIS SYSTEM OVER ITS PAST

COUPLE DAYS OF RUNS...SHOWING THE LEAST CONTINUITY.  WHILE ALL THE

DETERMINISTIC GUIDANCE AGREES ON TIMING...AS USUAL THE 12Z NAM IS

ON THE STRONG SIDE OF THE GUIDANCE.  WILL FAVOR THE NON-NAM

CONSENSUS WITH THIS SYSTEM...WHICH INCLUDES THE 12Z GFS/00Z ECMWF

SOLUTIONS...TO ACCOUNT FOR THE MINIMAL DIFFERENCES THAT REMAIN.



TROUGH MOVING THROUGH THE SOUTHWEST INTO THE SOUTHERN PLAINS...

THE NAM HAS TRENDED SLIGHTLY STRONGER WITH THIS SYSTEM OVER ITS

PAST DAY OF RUNS.  THE GFS HAS TRENDED QUICKER WITH THIS SYSTEM

OVER ITS PAST DAY OF RUNS.  THE ECMWF HAS TRENDED SOUTHWARD/SLOWER

WITH THIS SYSTEM AS IT EMERGES INTO THE PLAINS OVER ITS PAST

COUPLE DAYS OF RUNS DUE TO LESS OF A KICKER SHORTWAVE DEVELOPING

OVER THE GREAT BASIN/FOUR CORNERS.  AS USUAL...THE NAM IS ON THE

STRONG SIDE OF THE DETERMINISTIC/ENSEMBLE GUIDANCE WITH THE PAIR

OF SHORTWAVES MOVE OUT INTO THE PLAINS AND THE ASSOCIATED SURFACE

LOW NEAR THE MISSISSIPPI VALLEY/MIDWEST...WHICH LEADS TO A MUCH

MORE NORTHWESTERLY SURFACE LOW.  THE 00Z ECMWF ENSEMBLE MEMBERS

FAVOR THE ECMWF WITH THE SURFACE LOW...WHICH THE 09Z SREF MEMBERS

ARE CLUSTERED AROUND THE 06Z GFS/EAST OF THE 00Z UKMET.  THIS

ARGUES FOR A 06Z GFS/00Z ECMWF COMPROMISE DUE TO THE

UNCERTAINTY...WHICH BEARS SIMILARITY TO THE 12Z GFS/12Z UKMET WITH

THE SURFACE LOW PROGRESSION.



TROUGH APPROACHING NEW ENGLAND EARLY SUNDAY...

THE NAM HAS SHOWN REASONABLE CONTINUITY WITH THIS SYSTEM OVER ITS

PAST 12 HOURS OF RUNS...THOUGH IT IS SOUTH/SLIGHTLY MORE

PROGRESSIVE THAN ITS 11/12Z RUN.  THE GFS HAS TRENDED SLOWER WITH

THIS SYSTEMS PROGRESSION OVER ITS PAST DAY OF RUNS.  THE ECMWF HAS

SHOWN CONSIDERABLE VARIABILITY WITH THE DEPTH/TIMING OF THIS

SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS.  THE 06Z GFS IS A

PROGRESSIVE OUTLIER WITH THIS SYSTEM WHEN COMPARED TO THE OTHER

DETERMINISTIC GUIDANCE...INCLUDING THE 12Z NAM.  CONSIDERING THE

GFS TREND WITH THIS SYSTEM...WILL FAVOR THE SLOWER CONSENSUS WHICH

INCLUDES THE 12Z NAM/00Z ECMWF.



SHORTWAVE CROSSING NEW ENGLAND EARLY SATURDAY...

THE NAM HAS TRENDED QUICKER WITH THIS SYSTEM OVER ITS PAST DAY OF

RUNS.  THE GFS HAS TRENDED SLIGHTLY WEAKER WITH THIS SYSTEM OVER

ITS PAST DAY OF RUNS.  THE ECMWF SHOWS REASONABLE CONTINUITY WITH

THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS.  THE MODELS ARE IN

GOOD AGREEMENT CONCERNING THE FUTURE OF THIS SYSTEM.



...MODEL TREND GRAPHICS AT

WWW.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...



...500 MB FORECASTS AT WWW.HPC.NCEP.NOAA.GOV/H5PREF.SHTML...



ROTH

$$