MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1211 AM EDT MON MAY 05 2014 VALID MAY 05/0000 UTC THRU MAY 08/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. SYSTEM APPROACHING THE PACIFIC NORTHWEST EARLY THURSDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/ECMWF COMPROMISE CONFIDENCE: AVERAGE ALOFT, THE PARENT SHORTWAVE IS MOVING OVER A BROAD RIDGE, WHICH SHOULD LEAD TO A SYSTEM WEAKER THAN SEEN IN THE 00Z GFS SOLUTION (WHICH HAS TRENDED WEAKER SINCE ITS 18Z RUN). THE 00Z NAM IS UNIQUELY SLOW WITH THIS SYSTEM WHICH SHOULD BE MOVING QUICKLY IN THE SUPERGEOSTROPHIC/QUICK FLOW OVER THE TOP OF THE BROAD RIDGE, SO IT WAS DISCARDED. THE 12Z CANADIAN SOLUTION AT THE SURFACE ONLY HAD THE SUPPORT OF FIVE OF THE 90 12Z GLOBAL ENSEMBLE MEMBERS, SO IT IS A LOWER PROBABILITY/UNLIKELY SOLUTION. THE 12Z UKMET SEEMS TO HAVE NO INDICATION OF THIS SYSTEM WHATSOEVER. THE 12Z ECMWF/00Z GFS SOLUTIONS LIE IN THE MIDDLE OF THE BEST 12Z GLOBAL ENSEMBLE CLUSTERING, AND A COMPROMISE OF THE TWO IS PREFERRED TO DEAL WITH GFS BIASES WITH AVERAGE CONFIDENCE DUE TO ITS EXPECTED QUICK PROGRESSION. TROUGH MOVING THROUGH THE WEST INTO THE HIGH PLAINS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-UKMET COMPROMISE CONFIDENCE: ABOVE AVERAGE THERE ARE SLIGHT ISSUES ALOFT THAT LEAD TO A MORE NORTHEASTERN SURFACE LOW IN THE 12Z UKMET SOLUTION...ONE WHICH FALLS OUTSIDE THE 00Z GLOBAL ENSEMBLE SPREAD. THE UKMET BIAS ALSO ARGUES FOR A SLOWER SOLUTION FOR SYSTEMS MOVING THROUGH THE WESTERLIES. A NON-UKMET COMPROMISE HERE SHOULD IRON OUT THE REMAINING SMALL SCALE ISSUES WITH ABOVE AVERAGE CONFIDENCE DUE TO ITS AMPLIFIED NATURE. THE EAST ~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: HIGH THE GUIDANCE IS IN EXCELLENT AGREEMENT IN THIS REGION. A GENERAL MODEL COMPROMISE SHOULD DEAL WITH ANY RESIDUAL DETAIL ISSUES EFFECTIVELY, WITH HIGH CONFIDENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH