EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 303 AM EDT SAT MAR 19 2016 VALID 12Z TUE MAR 22 2016 - 12Z SAT MAR 26 2016 ...GUIDANCE/UNCERTAINTY ASSESSMENT AND FLOW PATTERN HIGHLIGHTS/THREATS... THE WPC MEDIUM RANGE PRODUCT SUITE WAS MAINLY DERIVED FROM A BLEND OF THE 12 UTC GFS/ECMWF AND GEFS/ECMWF ENSEMBLE MEANS THAT OFFER REASONABLY SIMILAR LARGER SCALE PATTERN EVOLUTION. MORE TROUBLESOME GUIDANCE RUN TO RUN INCONSISTENCY AND UNRESOLVED EMBEDDED SYSTEM AMPLITUDE/TIMING DIFFERENCES ARE EVIDENT THOUGH...SO FORECAST PREDICTABILITY IS NO BETTER THAN AVERAGE. HOWEVER...THIS BLEND SMOOTHES THESE MORE DIVERSE THAN NORMAL SMALL-MID SCALE DIFFERENCES AND MANUAL ADJUSTMENTS WERE THEN APPLIED TO DEPICT MORE SURFACE SYSTEM DEPTH/ORGANIZATION CONSIDERING DYNAMIC SUPPORT AND CONTINUITY. DYNAMIC/UNSETTLING UPSTREAM ENERGIES AND SURFACE SYSTEM DEVELOPMENT PROGRESS FROM THE ERN PACIFIC INLAND ACROSS THE WRN US EARLY-MID NEXT WEEK. LEAD SPRINGTIME WARMING AND POST-SYSTEM COOLING IS EXPECTED WITH SUBSEQUENT PROGRESSION IN SEPARATED MID-LATITUIDE SRN STREAM FLOW INTO THE S-CENTRAL US THROUGH MID-LATER NEXT WEEK. THIS IS ALBEIT IN A PATTERN WITH UNCERTAIN MULTI-STREAM INTERACTIONS/AMPLITUDE/TIMINGS AS ENERGY ALOFT AND LOWER ATMOSPHERIC COOLING SURGES SPILL SEWD OVERTOP FROM CANADA. THIS SCENARIO ALLOWS FOR A WIDESPREAD SWATH OF PCPN INCLUDING MODERATE NWRN US COASTAL RAINS AND TERRAIN ENHANCED SNOWS INLAND ACROSS THE WEST. THIS LEADS TO MID-LATE WEEK EMERGENCE OF QUITE A WAVY AND INCREASNGLY WELL DEFINED SURFACE FRONT TO FOCUS AN EMERGING WIDESPREAD EAST-CENTRAL TO ERN US HEAVIER PCPN THREAT AS FUELED BY DEEPENING GULF OF MEXICO MOISTURE RETURN. IN THIS PATTERN ALSO EXPECT POTENTIAL FOR ORGANIZED SNOW/ICE ON THE COLDER NRN PERIPHERY OF THE DEVELOPING PCPN SHIELD. SUBSEQUENT SECONDARY ENERGY DIGGING UPSTREAM INTO THE WRN US DAYS 6/7 ALSO SUPPORTS A RENEWED/COOLED SNOW SWATH THREAT ENHANCED BY TERRAIN OVER THE N-CENTRAL GREAT BASIN/ROCKIES. SCHICHTEL