EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 233 AM EDT THU MAR 20 2014 VALID 12Z SUN MAR 23 2014 - 12Z THU MAR 27 2014 ...WINTER STILL THREATENS BEYOND VERNAL EQUINOX... ...PATTERN OVERVIEW AND GUIDANCE/UNCERTAINTY ASSESSMENTS... MODELS AND ENSEMBLES HAVE CONVERGED UPON A MORE COMPATABLE/WELL CLUSTERED SOLUTION COMPARED TO YESTERDAYS GUIDANCE. THIS BOLSTERS CONFIDENCE IN EVOLUTION OF THE UPCOMING MEDIUM RANGE PATTERN AS AN ERN NOAM MEAN TROUGH AMPLIFIES WELL DOWNSTREAM FROM AN ERN PAC/ALASKA REX BLOCK...WITH RIDGING BUILDING AND WORKING INTO THE WRN US IN BETWEEN. WPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH ASSOCIATED SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY DERIVED FROM A COMPOSITE BLEND OF THE 12 UTC ECMWF AND ESPECIALLY THE ECMWF ENSEMBLE MEAN ALONG WITH LESSER INPUT FROM THE 18 UTC GFS/GEFS MEAN. THESE GUIDANCE SOURCE SOLUTIONS TEND TO CLUSTER FAIRLY WELL. THE COMBINATION BLEND PROVIDES GOOD WPC CONTINUITY AND ALSO NOW SEEMS COMPATABLE WITH NEWER GUIDANCE FROM THE 00 UTC GFS/ECMWF. ...SENSIBLE WEATHER HIGHLIGHTS... OVER THE WEST...MOST AREAS EXCEPT FOR THE EXTREME NORTH SHOULD SEE TEMPS 5-15F ABOVE NORMAL INTO MIDWEEK. EXPECT MAINLY DRY CONDITIONS THIS WEEKEND INTO EARLY NEXT WEEK WITH PACIFIC MOISTURE FINALLY REACHING THE WEST COAST AND FILTERING PCPN AND COOLING TEMPS INCREASINGLY INLAND TUE-THU. FROM THE PLAINS INTO THE EAST ANTICIPATE MULTIPLE DAYS WITH BROAD COVERAGE OF TEMPS 10-20F BELOW NORMAL WITH LOCALLY GREATER ANOMALIES POSSIBLE. SUCH DEPARTURES FROM NORMAL SHOULD BE SOMEWHAT MORE EXPANSIVE FOR MAX TEMPS VERSUS LOW TEMPS GIVEN WINDS AND SOME CLOUDS/MSTR AWAY FROM TWO COLD SFC HIGHS DROPPING SWD FROM CANADA. SEVERAL UPSTREAM SHORTWAVES MAY SUPPORT PERIODIC POCKETS OF SNOW WHERE AIR IS SUFFICIENTLY COLD WHILE MOISTURE/IMPULSES EMBEDDED IN SRN STREAM FLOW MAY GENERATE PASSING AREAS OF RAINFALL OVER THE FAR SOUTH. IN THIS PATTERN THERE MEANWHILE REMAINS SIGNIFICANT POTENTIAL FOR UNUSUALLY FAR SOUTHWARD EXTENT OF WINTRY PRECIPITATION FOR LATE MARCH. THE BEST CONSENSUS FOR WRN ATLANTIC COASTAL STORM INTENSIFICATION TUE-WED GIVES THE MID-ATLANTIC AND NORTHEAST THE HIGHEST THREAT OF MEANINGFUL LATE SEASON SNOW/WIND. SCHICHTEL