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This is the Model Diagnostic Discussion courtesy of HPC pertaining to Ida and future evolution of its remains:: MODEL DIAGNOSTIC DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 147 PM EST MON NOV 09 2009 VALID NOV 09/1200 UTC THRU NOV 13/0000 UTC ...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION INCLUDING THE NEW ECMWF AND FINAL PREFERENCES INITIALIZATION ERRORS WITH THE NAM/GFS DO NOT APPEAR TO SIGNIFICANTLY IMPACTS THEIR FORECASTS. Excerpt follows: PREFERENCE: 1/2 EACH GFS/ECMWF ...HURRICANE IDA... ...INTERACTION OF IDA WITH SHORTWAVE TROUGH OVER TEXAS... THE MAJORITY OF MODELS...INCLUDING THE NAM...ALLOW THE APPROACHING SHORTWAVE TROUGH TO PULL IDA IN A NORTHWESTERLY DIRECTION UNTIL THEY CONSOLIDATE NEAR THE GULF COAST BY 12Z TUE. HOWEVER... THE NAM LIES NEAR THE SOUTHWEST OR SLOW EDGE OF THE GUIDANCE DURING THIS PROCESS AND IS CONSIDERED LEAST RELIABLE...WHILE ALL OTHER GUIDANCE...INCLUDING THE GFS/ECMWF ALLOW THE CONSOLIDATED LOW TO DRIFT EASTWARD INTO THE FLORIDA PANHANDLE BY TUE...WHICH IS IN GOOD AGREEMENT WITH HURRICANE MODEL GUIDANCE. REFER TO THE TPC FOR THE OFFICIAL FORECAST. ...SHORTWAVE TROUGH AMPLIFYING OVER THE EAST TUE/WED... PREFERENCE: 1/2 GEFS MEAN TO 1/4 EACH GFS/CANADIAN THERE HAS BEEN A NOTABLE TREND IN THE MAJORITY OF GUIDANCE THE LAST TWO DAYS TO DELAY A COMPLICATED PHASING PROCESS OF THIS TROUGH WITH A SEPARATE SHORTWAVE TROUGH MOVING INTO THE SOUTHEAST UNTIL BOTH TROUGHS REACH THE EAST COAST. THE NAM AND MULTI-MODEL ENSEMBLE MEANS WERE FIRST TO DISPLAY A LESS-PHASED OR UNPHASED SOLUTION 1-2 DAYS AGO...WITH THE DETERMINISTIC GUIDANCE SLOWLY COMING INTO AGREEMENT. THE NEW NAM CONTINUES TO SHOW NO PHASING...BUT IS MOSTLY DUE TO ITS SLOW OUTLIER SOLUTION IN THE GULF...SO THE NAM CAN NOT PHASE. MEANWHILE THE NEW GFS HAS TRENDED TOWARD SLOWER AND WEAKER PHASING...RESULTING IN A LESS PRONOUNCED SURFACE LOW OFF THE GA/SC COAST...WITH REASONABLY GOOD SUPPORT PROVIDED FROM THE CANADIAN AND GEFS MEAN... ALBEIT WEAKER AND MORE SUPPRESSED THAN THE GFS. THE ECMWF/UKMET NOW REMAIN THE ONLY DETERMINISTIC SOLUTIONS SUPPORTING CONSIDERABLE SURFACE LOW DEVELOPMENT OFF THE SC COAST BY THU. THUS...WILL MAINTAIN CONTINUITY WITH PRIOR REASONING THAT THE POSITIVELY-TILTED LONGWAVE PATTERN AND ITS SUBSEQUENT SHORTWAVE PATTERN SUPPORT A SUPPRESSED AND PROGRESSIVE SURFACE LOW EVOLUTION...WHICH IS CLOSEST TO THE GEFS MEAN. ...MODEL TREND GRAPHICS AT www.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML... ...500 MB FORECASTS AT www.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML... |