EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1155 AM EDT TUE JUN 10 2014 VALID 12Z FRI JUN 13 2014 - 12Z TUE JUN 17 2014 ...FLOW PATTERN/SENSIBLE WEATHER HIGHLIGHTS AND GUIDANCE/UNCERTAINTY ASSESSMENT... THE MEDIUM RANGE MODELS AND ENSEMBLES HAVE TO CONVERGED UPON AN INCREASINGLY COMMON MEDIUM TO LARGER SCALE FLOW EVOLUTION THAT IS PRIMARILY COMPRISED FROM UNSETTLING PIECES OF AMPLIFIED/COOLING WRN US MID-UPPER LEVEL ANCHORING TROUGH ENERGY EJECTING NEWD ACROSS MID-CONTINENT. THIS SHOULD FAVOR LATE SEASON LOCALLY HEAVY SNOWFALL OVER THE NRN ROCKIES AND PERIODS OF ORGANIZED STRONG CONVECTION/MCS ACTIVITY OVER THE N-CENTRAL STATES WITH FRONTAL/BOUNDARY PASSAGE AND WITH LESS AREAL COVERAGE FURTHER SOUTH AHEAD OF A PERSISTENT DRYLINE. A COOLING AND LINGERING DOWNSTREAM TROUGH ALOFT OVER THE NERN US/ERN CANADA INTO THE WEEKEND AND SUBSEQUENT MID-UPPER LEVEL RIDGE BUILDING/SUMMER WARMING OVER THE ERN THROUGH SRN/SERN US ALSO ACTS TO TRAP SOME SLOW MOVING AND CONVECTION FOCUSING VORTS THAT MAY LEAD TO LOCALLY HEAVY RAINS...MAINLY OVER THE CENTRAL GULF COAST STATES AND SERN US. IMPROVED FORECAST TOOL CLUSTERING BOLSTERS ASSOCIATED FORECAST CONFIDENCE TO MORE REASONABLE LEVELS. EVEN SO...SIGNIFICANT LINGERING SMALLER SCALE FEATURE/CONVECTION VARIANCE IN DETERMINISTIC RUNS AND RELATED LOCAL SENSIBLE WEATHER FOCUS ISSUES ARGUE FOR AN ENSEMBLE APPROACH TO MAXIMIZE FORECAST CONTINUITY CONSISTENT WITH UNCERTAINTY AS HIGHLIGHTED BY THE MORE PREDICTABLE WEATHER COMPONENTS. ACCORDINGLY...WPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH THE HPCGUIDE SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY DERIVED FROM A BLEND OF COMPATABLE GUIDANCE FROM THE 00 UTC NAEFS/ECMWF ENSEMBLE MEANS. THE 00 UTC GFS ENSEMBLE MEAN AND GFS/ECMWF DETERMINISTIC RUNS ARE ALSO IN THIS BALLPARK OVERALL. SCHICHTEL