THE 12Z GUIDANCE CONTINUES TO SHOW A MODERATE DEGREE OF SPREAD WITH BOTH THE TIMING AND INTENSITY OF SHORTWAVES ALONG THE CANADIAN BORDER THIS PERIOD. THE LATEST GEFS MEAN AND UKMET ARE CLOSEST TO THE 00Z ECENS MEAN...USED FOR THE UPDATE PACKAGE...WITH THIS 12Z GUIDANCE SLIGHTLY FASTER WITH THE PROGRESSION OF POLAR CYCLONES. THE GFS AND PARALLEL GFS STILL DO NOT CLUSTER WELL ENOUGH WITH THE BULK OF THE OTHER GUIDANCE TO BE VERY RELIABLE. CHANGED THE GULF TROPICAL WAVE TROUGH TO A LOW CENTER...AS PER COORDINATION WITH TPC. NONE OF THE NEW MODELS DEVELOP THIS SYSTEM TO A SUBSTANTIAL DEGREE. OTHERWISE...MADE ONLY MINIMAL CHANGES FOR THE FINAL ISSUANCE. (emphasis added by danielw) http://www.srh.noaa.gov/productview.php?pil=PMDEPD&max=61