MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 327 AM EDT SAT JUL 25 2015 VALID JUL 25/0000 UTC THRU JUL 28/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC/ECMWF ...INITIAL UPPER TROUGH OVER THE UPPER MIDWEST... ...COLD FRONT CROSSING THE GREAT LAKES... PREFERENCE: BLEND OF THE 25/00Z GFS/ECMWF CONFIDENCE: ABOVE AVERAGE THE MODELS WERE IN PRETTY GOOD AGREEMENT IN TAKING THE UPPER TROUGH OVER THE GREAT LAKES AND CENTRAL ONTARIO OFF TO THE EAST OVER THE NEXT COUPLE OF DAYS. THIS WILL DRIVE A COLD FRONT EAST ACROSS THE GREAT LAKES REGION. BY LATE SAT AND SUN...THE 00Z NCEP GUIDANCE TENDED TO REMAIN ON THE WEAKER SIDE OF THE GUIDANCE WHILE THE NON NCEP GUIDANCE...SAVE FOR THE ECMWF...WAS ON THE STRONGER SIDE OF THE ENVELOPE OF SOLNS. WILL CONTINUE TO FAVOR THE WEAKER SOLNS BASED ON THE ENSEMBLE GUIDANCE. IN ADDITION...THE ECMWF AND GFS WERE IN GOOD AGREEMENT WITH EACH OTHER AND BOTH MODELS HAD STRONG RUN TO RUN CONTINUITY. ...UPPER LOW/TROUGH DIGGING INTO WESTERN BRITISH COLUMBIA... ...TROUGH RELOADING IN THE WEST LATER TODAY AND SUN... ...CYCLOGENESIS OVER THE NORTHERN HIGH PLAINS... PREFERENCE: BLEND OF THE 25/00Z GFS/ECMWF CONFIDENCE: SLIGHTLY ABOVE AVERAGE AN UPPER LOW AND ASSOCIATED TROUGH DIGGING SOUTHEAST OUT OF THE GULF OF AK WILL DROP DOWN ACROSS BRITISH COLUMBIA LATER TODAY AND THEN CONTINUE HEADING INTO THE NORTHWEST U.S. SUN AND MON. A LARGER SCALE TROUGH ASSOCIATED WITH THE UPPER LOW WILL RELOAD THROUGHOUT THE INTERMOUNTAIN WEST. MEANWHILE...LEE-SIDE CYCLOGENESIS OVER THE NORTHERN HIGH PLAINS WILL OCCUR BY MON. THE 00Z SUITE OF GUIDANCE WAS SIMILAR TO THE 12Z MODEL RUNS. A NON UKMET CONSENSUS STILL LOOKS LIKE THE BEST BET. ...UPPER TROUGH SWINGING THROUGH THE NORTHEAST AND OUT TO SEA TODAY... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS SHOW VERY GOOD AGREEMENT AND RUN TO RUN CONSISTENCY IN TAKING THE CURRENT TROUGH DIGGING INTO THE NORTHEAST GRADUALLY EAST AND THEN OUT ACROSS THE CANADIAN MARITIMES TODAY. A GENERAL MODEL COMPROMISE IS PREFERRED. ...MID LEVEL TROUGH IMPACTING THE SOUTHEAST/FL PENINSULA... PREFERENCE: NON 00Z NAM CONSENSUS CONFIDENCE: AVERAGE THE MODELS INDICATE THE DEVELOPMENT OF A SW/NE ORIENTED MID LEVEL TROUGH AXIS THIS WEEKEND EXTENDING FROM THE EASTERN GULF OF MEXICO TO THE SOUTHWEST ATLANTIC BASIN WITH A FRONTAL ZONE WILL BE DRAPED ACROSS THE SAME AREA. THE NUMERICAL GUIDANCE STILL INDICATES THAT THERE WILL BE DEVELOPMENT OF MULTIPLE WAVES OF LOW PRESSURE. THE ECMWF BACKED AWAY FROM THE IDEA OF ITS DEEPER SOLN OFF THE GA/SC COAST BUT SHIFTED THE FOCUS OF A SOMEWHAT MARGINALLY STRONGER SOLN OFF THE WEST COAST OF FL PRIMARILY ON DAY 2. THE ECMWF LOOKS TO FIT IN BETTER WITH THE MODEL CONSENSUS...SO FOR NOW WILL SIMPLY LEAVE OUT THE NAM FROM THE MODEL CONSENSUS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN