MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1205 AM EDT TUE OCT 6 2015 VALID OCT 6/0000 UTC THRU OCT 9/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION, INCLUDING THE NAM AND GFS THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 00Z NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS. ***PERSISTENT CLOSED LOW OFF THE SOUTHEASTERN U.S. COAST*** PREFERENCE: A NON-00Z NAM MODEL CONSENSUS CONFIDENCE: ABOVE AVERAGE WATER VAPOR IMAGERY CONTINUES TO SHOW AN IMPRESSIVE CLOSED LOW SPINNING OFF THE GEORGIA COAST. THIS SLOW-MOVING SYSTEM, WHICH HAS TAKEN MULTIPLE DAYS TO MIGRATE FROM ALABAMA TO THE SOUTHEASTERN U.S. COASTAL WATERS, WILL CONTINUE TO LIFT NORTH AND EAST. IT IS FORECAST TO WEAKEN AND EVOLVE INTO A OPEN WAVE ALOFT BY 36 HOURS AS IT GRADUALLY BECOMES ABSORBED BY THE PREVAILING WESTERLIES. THE 00Z NAM IS ONLY SLIGHTLY STRONGER THAN THE MODEL CONSENSUS AND SLIGHTLY QUICKER THAN THE REMAINDER OF THE MODELS, WHICH ARE IN CLOSE AGREEMENT. THEREFORE, WE WILL FAVOR A NON-00Z NAM MODEL CONSENSUS WITH THIS SYSTEM. ***CLOSED LOW OVER THE SOUTHWESTERN U.S.*** PREFERENCE: BLEND OF THE 12Z ECMWF AND 00Z GFS CONFIDENCE: AVERAGE THE OTHER CLOSED FEATURE ON THE MAP CONSISTS OF AN ANOMALOUS UPPER LOW MOVING SLOWLY ACROSS SOUTHERN CALIFORNIA. THROUGHOUT THE NEXT COUPLE OF DAYS, THIS SYSTEM WILL GRADUALLY MIGRATE EASTWARD REACHING WESTERN TEXAS TOWARD THE END OF THE WEEK. THE 00Z GFS AND 12Z ECMWF ARE CLOSE TO THE MODEL CONSENSUS, AND THAT WILL BE THE FAVORED PREFERENCE FOR NOW. ***SHORTWAVE TROUGH TRACKING ALONG THE UPPER MIDWEST AND GREAT LAKES THROUGH TUESDAY*** PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE A NORTHERN STREAM SHORTWAVE WILL GENERALLY SKIRT THE NORTHERN TIER OF THE COUNTRY AND EVENTUALLY LIFT INTO ONTARIO. MODELS AGREE SUFFICIENTLY WHICH SUPPORTS A GENERAL MODEL COMPROMISE. ***UPPER LEVEL TROUGH AND SURFACE LOW ACROSS THE NORTHERN U.S. MIDWEEK*** PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF CONFIDENCE: AVERAGE A QUICK MOVING IMPULSE WILL RACE FROM THE NORTHERN HIGH PLAINS TOWARD THE GREAT LAKES ON DAY 3 OF THE PERIOD. THE LARGEST VARIABILITY IN THE SOLUTION REVOLVES AROUND THE SURFACE LOW TRACK. THERE ARE TWO DISTINCT CAMPS WITH A MAJORITY OF THE MODELS CHOOSING THE NORTHERN CLUSTER, EXCEPT THE GFS/ECMWF SUITES. ENSEMBLE LOW PLOTS SUPPORT THE SOUTHERN CLUSTERING MUCH MORE CLOSELY WHICH IS ALONG THE LINES OF THE 00Z GFS/ECMWF. THE PREFERENCE IS A BLEND OF THE 00Z GFS/12Z ECMWF. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... HAMRICK