EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1224 AM EDT SUN JUN 07 2015 VALID 12Z WED JUN 10 2015 - 12Z SUN JUN 14 2015 ...OVERVIEW AND MODEL GUIDANCE PREFERENCES... MEDIUM RANGE PERIOD TO BE CHARACTERIZED BY TROUGHING IN THE WESTERN STATES AND ALONG THE US/CANADIAN BORDER WITH RIDGING NOSING INTO THE SOUTHEASTERN STATES. THIS SHOULD YIELD A RATHER SUMMERY FEEL IN THE EAST BUT A RATHER ANOMALOUSLY WETTER STRETCH OF DAYS FOR THE WESTERN AND CENTRAL STATES. THE MODELS/ENSEMBLES HAVE WAVERED IN THE HANDLING OF THE SHORTWAVES WITHIN THE LONGER WAVELENGTH FLOW FOR SEVERAL RUNS... AND THERE REMAINS DISAGREEMENT BETWEEN THE ECMWF ENSEMBLES AND THE GEFS/CANADIAN ENSEMBLES UPSTREAM IN THE NORTHEAST PACIFIC LATER IN THE WEEK... WHICH HAS BEEN A PROBLEM ARE OF LATE. 18Z GFS AND 12Z ECMWF OFFERED A REASONABLE BLENDED SOLUTION TO START BUT TRENDED TOWARD AN 18Z GEFS AND 12Z ECENS MEAN BLEND BY NEXT WEEKEND TO MITIGATE PESKY DETAIL/TIMING/AMPLITUDE DIFFERENCES. ...SENSIBLE WEATHER HIGHLIGHTS... FRONTAL BOUNDARY INITIALLY MOVING THROUGH THE GREAT LAKES ON WEDNESDAY WILL GET HUNG UP IN THE NORTHEAST -- PROBABLY CLOSE TO THE US/CANADIAN BORDER -- AS IT FIGHTS INCREASED RIDGING TO ITS SOUTH AND AN UPPER FLOW PARALLEL TO THE SFC BOUNDARY. TEMPERATURES WILL BE ABOVE AVERAGE AND ISOLATED SHOWERS/STORMS WILL FOCUS NEAR THE FRONT AND IN THE WARM SECTOR IN GENERAL. TAIL END SHOULD PUSH INTO THE CENTRAL PLAINS BEFORE DISSIPATING WITH DIMINISHING UPPER SUPPORT. SHORTWAVE STILL HAS GOOD ENSEMBLE SUPPORT FOR AN AREA OF QPF -- POSSIBLY A FEW INCHES OVER A FEW DAYS -- INVOF NE/SD/MN/IA AS IT SHEARS EASTWARD. THE WEST AND PAC NW IS A BIT MORE COMPLICATED. THE REMNANTS OF HURRICANE BLANCA SHOULD BE INDISCERNIBLE FROM THE BACKGROUND SURFACE PRESSURES IN THE DESERT SOUTHWEST ON WEDNESDAY. ADDED LOWER/MID-LEVEL MOISTURE SHOULD INCREASE THE RISK OF SCATTERED SHOWERS IN THE SOUTHWEST/GREAT BASIN AS A WHOLE... AIDED BY WEAK TROUGHING MOVING THROUGH THE GREAT BASIN. TO THE NORTH... ENSEMBLES STILL CANNOT FIGURE OUT HOW TO TRANSLATE N PAC ENERGY INTO W CANADA. ECMWF ENSEMBLE MEAN WAS CURIOUSLY FLAT BY FRIDAY WHEN ONGOING PREFERENCE WAS FOR AT LEAST SOME TROUGHING TO DIG A BIT INTO BRITISH COLUMBIA -- THUS THE GEFS COMPROMISE. LOWER HEIGHTS BY NEXT SUN SHOULD BRING IN COOLER TEMPS TO THE PAC NW... THOUGH TO WHAT DEGREE DIFFERS BY ENSEMBLE SYSTEM /ECMWF MEMBERS ARE FLATTER AND MILDER/. FRACASSO