EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 156 AM EST WED NOV 11 2015 VALID 12Z SAT NOV 14 2015 - 12Z WED NOV 18 2015 ...OVERVIEW OF THE SYNOPTIC PATTERN... AN UPPER TROUGH WILL MOVE INLAND AND AMPLIFY OVER THE WESTERN U.S. THIS WEEKEND AS DOWNSTREAM RIDGING BUILDS IN BEHIND A DEEP VORTEX LIFTING OUT OF THE NORTHEAST. ENERGY WITHIN THE AMPLIFYING TROUGH IS EXPECTED TO SPLIT WHILE APPROACHING THE ROCKIES EARLY NEXT WEEK. THE NORTHERN PORTION SHOULD QUICKLY PROGRESS THROUGH THE UPPER MIDWEST WHILE THE SOUTHERN PORTION OF THE ENERGY COULD POTENTIALLY CLOSE OFF ANOTHER UPPER LOW OVER THE SOUTH CENTRAL U.S. BY THE MIDDLE OF NEXT WEEK. ...MODEL EVALUATION/PREFERENCES... THE LARGEST UNCERTAINTY IN THE FORECAST CONTINUES TO BE WITH THE UPPER TROUGH AMPLIFYING OVER THE WEST...ESPECIALLY AS IT BEGINS CROSSING THE INTERMOUNTAIN WEST AND ROCKIES EARLY NEXT WEEK. ALTHOUGH THE MAJORITY OF DETERMINISTIC MODELS HAVE COME INTO BETTER AGREEMENT WITH SPLITTING THE ENERGY AND CLOSING OFF AN UPPER LOW IN THE SOUTHERN TIER...THERE IS STILL A LOT OF SPREAD WITH THE EXACT TIMING AND AMPLITUDE. THE GFS CONTINUES TO ADVERTISE A SLOWER/MORE AMPLIFIED SOLUTION THAN THE ECMWF...BUT NOW HAS SUPPORT FROM THE LATEST CMC/UKMET. GIVEN THAT THE ENSEMBLE MEANS HAVE YET TO FULLY LATCH ON TO THE IDEA OF SPLITTING THE ENERGY AND CLOSING OFF AN UPPER LOW...AND CONSIDERING THERE IS STILL A LOT OF NOISE IN THE INDIVIDUAL ENSEMBLE MEMBERS...THE WPC DAY 3-7 FORECAST STAYED CLOSE TO ENSEMBLE MEAN GUIDANCE. ...SENSIBLE WEATHER HIGHLIGHTS... STRONG ONSHORE FLOW INTO THE TERRAIN WILL DRIVE HEAVY RAIN AND MOUNTAIN SNOW OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES THIS WEEKEND. BY EARLY NEXT WEEK...THE FOCUS WILL SHIFT TO THE SOUTH CENTRAL U.S....WHERE MOISTURE RETURNING FROM THE GULF COULD FUEL HEAVY RAINS OVER TEXAS ON MONDAY...POTENTIALLY SPREADING INTO THE LOWER/MIDDLE MISSISSIPPI AND TENNESSEE VALLEYS TOWARDS THE MIDDLE OF THE WEEK. GERHARDT