MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 235 AM EDT THU APR 16 2015 VALID APR 16/0000 UTC THRU APR 19/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION WITH PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. KICKER SHORTWAVE MOVING NEAR THE US/CANADIAN BORDER ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: ECMWF/GFS COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE A PROGRESSIVE AND DEVELOPING BROAD UPSTREAM RIDGE IS SEEN IN THE GUIDANCE WEST OF THIS SYSTEM. THE GUIDANCE HAS FOLLOWED THE LEAD OF THE NAM/GFS RUNS FROM 00Z AND DUG THE SYSTEM MORE TO THE SOUTH. THE 00Z CANADIAN/00Z UKMET ARE THE MOST AGGRESSIVE WITH THIS DIGGING. TO MAINTAIN SOME SEMBLANCE OF CONTINUITY, PREFER A COMPROMISE OF THE 00Z ECMWF/00Z GFS HERE WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE. ENERGY ALOFT DROPPING DOWN THE CA COAST SAT/SUN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE ALLOWS ENERGY AT 500 HPA TO DROP SOUTHWARD AS RIDGING BUILDS NEAR VANCOUVER ISLAND. THE 00Z CANADIAN AND 00Z NAM ARE ON OPPOSITE ENDS OF THE GUIDANCE STRENGTH-WISE, THOUGH MOST OF THE GUIDANCE SHOWS A SIMILAR PROGRESSION. USING THE CONSENSUS AS OUR GUIDE, A COMPROMISE OF THE NON-NAM GUIDANCE IS PREFERRED HERE WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE. CLOSED LOW EMERGING INTO THE PLAINS SAT/SUN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE SHOWS MUCH BETTER AGREEMENT WITH THIS SYSTEM. A GENERAL MODEL COMPROMISE WILL DEAL WITH ANY LINGERING DETAIL ISSUES EFFECTIVELY, WHICH IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. SHORTWAVE CROSSING NEW ENGLAND SAT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE THE NAM SHOWS UP ON THE SLOW FRINGE OF THE GUIDANCE WITHIN THE DETERMINISTIC AND 12Z GLOBAL ENSEMBLE GUIDANCE -- ONE OF ITS KNOWN BIASES. PREFER A NON-NAM COMPROMISE HERE WITH ABOVE AVERAGE CONFIDENCE. SHORTWAVE CROSSING NEW ENGLAND FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE IS IN GOOD AGREEMENT WITH THESE FEATURES. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH