MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 142 AM EST SAT JAN 04 2014 VALID JAN 04/0000 UTC THRU JAN 07/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION INCLUDING FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. NORTHERN STREAM SHORTWAVE TROUGH/SURFACE LOW(S) IMPACTING THE N-CNTRL U.S. TODAY COLD FRONT CROSSING THE CENTRAL U.S. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON 00Z NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE IS IN GOOD AGREEMENT OUTSIDE OF THE 00Z NAM WHICH SLOWED DOWN WITH THE MID-LEVEL SHORTWAVE EARLY TODAY OVER THE N-CNTRL STATES. THE PREVIOUS 12Z NAM APPEARED OKAY AND IT IS NOT CLEAR WHY THE RECENT NAM SHIFTED SLOWER. REMAINING MODEL GUIDANCE FORMS A GOOD COMPROMISE. BURGEONING TROUGH MID-CONTINENT SURFACE LOW TRACKING FROM THE SRN PLAINS TO THE LOWER GREAT LAKES FROM SAT THROUGH MON ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z ECMWF/CANADIAN/GFS COMPROMISE CONFIDENCE: AVERAGE THE ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT WITH A SURFACE LOW EXPECTED TO TRACK FROM THE SRN PLAINS INTO QUEBEC BY MON MORNING...WITH THE EC...GEFS...AND CMC MEMBERS MOSTLY AGREEING ON A POSITION NOW. THE 00Z UKMET ADJUSTED QUICKER FROM ITS 12Z RUN...BUT IS STILL SLOWER THAN THE CONSENSUS...WHILE THE NAM IS THE STRONGEST OF THE DETERMINISTIC MODELS. THE 00Z GFS/ECMWF/CMC HAVE GOOD AGREEMENT AND REPRESENT THE BEST COMPROMISE OF THE CURRENT AVAILABLE MODELS. WEAK UPPER DISTURBANCES APPROACHING THE WEST COST EARLY NEXT WEEK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: BELOW AVERAGE A SMALL VORT CENTER JUST WEST OF CALIFORNIA AND ADDITIONAL UPPER TROUGHING ORIGINATING NEAR LONGITUDE 150 W WILL ATTEMPT TO AFFECT THE WEST COAST WITH UNSETTLED WEATHER...UNDERCUTTING THE PERSISTENT E-PAC RIDGE BY LATE MON INTO TUE. CONFIDENCE IN THE DETAILS IS LOW DUE TO THE COMPLEXITY OF POSSIBLE EVOLUTIONS...BUT THERE IS BROAD AGREEMENT ON THE EVOLUTION OF FEATURES ALONG THE WEST COAST NOW THAT 00Z CMC HAS COME BACK TOWARD THE REMAINING MODEL CONSENSUS. REGARDING THE SURFACE CYCLONE...IT IS DIFFICLUT TO PUT TOO MUCH FAITH IN ANY ONE SOLUTION AT THIS MUCH LEAD TIME...BUT THE MODEL TIMING IS SIMILAR AND THE STRENGTH SEEN IN THE MODELS IS GENERALLY WEAK...WHICH FITS THE DISORGANIZED/DEAMPLIFIED NATURE OF THE UPPER TROUGHING FORECAST IN THE EASTERN PACIFIC. www.wpc.ncep.noaa.gov/html/model2.shtml... OTTO