EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1155 AM EDT SAT APR 09 2016 VALID 12Z TUE APR 12 2016 - 12Z SAT APR 16 2016 ...OVERVIEW AND GUIDANCE/UNCERTAINTY ASSESSMENT... THE LATEST MODELS AND ENSEMBLES CONTINUE TO CONVERGE UPON A MORE COMMON FLOW SOLUTION FROM THE PACIFIC INLAND ACROSS MUCH OF NORTH AMERICA THROUGH THROUGH MEDIUM RANGE TIME SCALES. PREFERENCE REMAINS THAT THERE WILL BE SIGNIFICANT AMPLIFICATION OF NERN PAC TROUGHING INTO THE WEST WHILE THE DOWNSTREAM RIDGE PROGRESSES ACROSS THE ROCKIES/PLAINS AND INTO THE E-CENTRAL US. AT THE SAME TIME AN ERN NOAM MEAN TROUGH CONSISTING OF A COMBINATION OF NRN STREAM FLOW AND BY THE LATTER HALF OF THE PERIOD SRN STREAM/TIER TRACKING ENERGY WORKS OFF THE EAST COAST WITH LOWS UP OVER THE WRN ATLANTIC INTO FRI-SAT. THE WPC SURFACE MEDIUM RANGE PRODUCT SUITE HAS BEEN PRIMARILY DERIVED FROM A BLEND OF BEST CLUSTERED GUIDANCE FROM THE 06 UTC GEFS MEAN AND THE 00 UTC ECMWF/ECMWF ENSEMBLE MEAN. APPLIED MOST WEIGHTING TO THE ECMWF ENSEMBLE MEAN IN THIS BLEND TO MAINTAIN MAX WPC CONTINUITY. RECENT ECMWF ENSEMBLE MEAN RUNS HAVE BEEN VERIFYING VERY WELL RECENTLY DESPITE RECENT PERIODS OF GREATER THAN AVERAGE UNCERTAINTY THAT SEEMS TO BE RESOLVING. ...SENSIBLE WEATHER HIGHLIGHTS/THREATS... IT REMAINS EVIDENT THAT WEATHER WILL BECOME INCREASINGLY ACTIVE/UNSETTLED ACROSS THE WEST AND EVENTUALLY INTO THE PLAINS AS UPR TROUGHING AMPLIFIES INTO AND MOVES ACROSS THE WEST. LOCALLY ENHANCED RAIN/HIGH ELEV SNOW WILL BE PSBL ESPECIALLY OVER THE NRN 2/3 OF THE WEST... WITH DETAILS ABLE TO BE REFINED ONCE THERE IS BETTER AGREEMENT ON THE EXISTENCE/TRACK OF AN EMBEDDED UPR LOW. BY LATE IN THE WEEK THE GRADUAL ADVANCE OF THE UPR TROUGH SHOULD LEAD TO INCREASING COVERAGE/INTENSITY OF PLAINS RNFL WHILE ACTIVITY TAPERS OFF FROM THE WEST COAST INLAND. THIS SYSTEM WILL BRING DAYS OF COOL TEMPS TO THE WEST WHILE PROMOTING SOME WARM TEMPS SPREADING DOWNSTREAM FROM THE PLAINS. A WAVY FRONT NEAR THE GULF COAST TUE WILL FOCUS GULF MOISTURE WITH SOME LEAD THREAT OF LOCALLY HEAVY RAINFALL. SRN STREAM ENERGY EJECTING FROM THE SOUTHWEST THEN HELPS TO GENERATE ANOTHER AREA OF HEAVIER RNFL FROM PARTS OF TX EWD ALONG THE GULF COAST/SERN US. THE PERIOD WILL START OFF VERY CHILLY OVER THE EAST WITH GREATEST ANOMALIES OF MINUS 10-20F FOR HIGHS OVER THE MIDWEST/GREAT LAKES TUE. COOL TEMPS OVER THE EAST WILL PERSIST THE LONGEST NEAR THE EAST COAST AND ESPECIALLY LINGER WITH MIN TEMPS UNDER THE SETTLED POST-FRONTAL HIGH PRESSURE...WHILE PLAINS WARMTH GRADUALLY SPREADS TO THE E-CENTRAL US IN RETURN FLOW AHEAD OF PLAINS FRONTOGENESIS ON THE WRN PERIPHERY OF THE ERN US HIGH. SCHICHTEL