EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1148 AM EDT SUN JUN 01 2014 VALID 12Z WED JUN 04 2014 - 12Z SUN JUN 08 2014 ...OVERVIEW AND PREFERENCES... IN THE LARGER SCALE THE PRIMARY FEATURES OF NOTE WILL BE A RIDGE ACROSS NRN MEXICO... A WRN NOAM MEAN TROUGH WHOSE EMBEDDED ENERGY SHOULD DRIFT INTO CNTRL NOAM NEXT WEEKEND... AND A TROUGH CROSSING SERN CANADA AND THE NERN CONUS. OPERATIONAL MODELS/ENSEMBLES STILL SHOW CONSIDERABLE SPREAD WITH IMPORTANT FCST DETAILS OVER THE ERN HALF OF THE CONUS AS WELL AS OVER THE GULF OF MEXICO. THE SCALE OF SOME OF THESE DETAILS IS SUFFICIENTLY SMALL TO SUGGEST IT MAY TAKE A WHILE FOR CONFIDENCE EXCEED LOW-AVG LEVELS. AN OVERALL REVIEW OF CONTINUITY/CONSENSUS LEADS TO FAVORING A BLEND OF THE 00Z ECMWF MEAN AND LAST TWO ECMWF RUNS AS THE BEST REFLECTION OF THE MOST AGREEABLE ASPECTS OF GUIDANCE AT THIS TIME. ...GUIDANCE EVALUATION... AN EARLY DIVERGENCE IN SOLNS ARISES THE COMBINATION OF A SHRTWV IMPULSE REACHING THE N-CNTRL PLAINS AS OF EARLY DAY 3 WED AND NRN STREAM TROUGH ENERGY CROSSING SERN CANADA AND THE GRTLKS/NORTHEAST. THE 00Z/06Z GFS AND 00Z GEFS MEAN ARE FASTER THAN MOST OTHER GUIDANCE WITH THE NRN STREAM TROUGH AND LEAVE THE N-CNTRL PLAINS SHRTWV BEHIND... WITH CORRESPONDING TIMING DIFFS AT THE SFC. THE PAST FEW ECMWF MEAN RUNS ALONG WITH THE PAST TWO ECMWF RUNS AND LATEST UKMET/CMC PROVIDE THE MOST SIMILAR EVOLUTION THAT YIELDS A MODERATELY STRONG SFC LOW NEAR THE NRN NEW ENGLAND COAST/CANADIAN MARITIMES AS OF EARLY DAY 5 FRI. THE 06Z GEFS MEAN LOOKS BETTER THAN THE 00Z VERSION IN SOME WAYS BUT APPEARS WEAK WITH ITS NRN STREAM ENERGY RESULTING IN SLOW SFC TIMING. WITHIN THE WRN MEAN TROUGH THERE ARE STILL SOME DETAIL UNCERTAINTIES WITH THE CORE OF MID LVL ENERGY CROSSING THE WRN HALF OF SRN CANADA BUT DIFFS ARE APPROACHING TYPICAL ERROR MAGNITUDES FOR THE TIME FRAME INVOLVED. AT MOST FCST HRS THE PREFERRED BLEND OFFERS AN INTERMEDIATE TIMING BETWEEN THE FASTER 06Z GFS AND SLOWER 00Z GFS. THERE IS FAIR AGREEMENT THAT THE CONUS PART OF THE WRN TROUGH SHOULD REACHING THE PLAINS DURING THE WEEKEND AND SUPPORT A SFC WAVE NEAR THE MS VLY. THE 00Z GFS/CMC MAY BE OVER-DEVELOPED AT LEAST PARTIALLY IN RESPONSE TO FCST CONVECTION. THERE HAS BEEN NO IMPROVEMENT IN THE GUIDANCE SPREAD REGARDING PSBL SFC DEVELOPMENT OVER/NEAR THE GULF OF MEXICO. MODELS/ENSMEANS ARE CONSISTENT IN SHOWING A MEAN RIDGE BUILDING WWD OVER AND JUST N OF THE CARIBBEAN... WHICH MAY SUPPORT SOME NEWD PROGRESSION OF MSTR ALOFT FROM THE SRN GULF/NWRN CARIBBEAN. GEFS/ECMWF ENSEMBLE GUIDANCE HAS BEEN CONFINING THE BEST COMBINATION OF DEEP MSTR AND LOW SHEAR TO THE SWRN HALF OF THE GULF SO CONFIDENCE IS NOT THAT GREAT IN A WELL DEFINED GFS-LIKE SFC SYSTEM TRACKING NEWD OVER AN AREA WHERE CONSENSUS SHOWS BROAD SELY LOW LVL FLOW. ...SENSIBLE WEATHER HIGHLIGHTS... ONE PRIMARY FOCUS FOR LOCALLY HVY CONVECTION WILL BE ALONG A WAVY SFC FRONT BECOMING ESTABLISHED FROM THE CNTRL/S-CNTRL PLAINS INTO THE MID ATLC. AREAS FROM THE PLAINS INTO THE MS VLY SHOULD HAVE THE HIGHEST POTENTIAL FOR HVY RNFL WITH SEPARATE MIDWEEK AND WEEKEND SFC WAVES HELPING TO STRENGTHEN LOW LVL INFLOW. ONE OR MORE WEAK SHRTWVS EMBEDDED WITHIN LOW AMPLITUDE FLOW ALOFT MAY ALSO GENERATE CONVECTION ACROSS THE CNTRL PORTIONS OF THE PLAINS/ERN STATES. MEANWHILE A COLD FRONT SLOWLY DROPPING INTO/THROUGH THE NRN PLAINS WILL SERVE AS ANOTHER FOCUS FOR PSBL HVY RNFL. THE NORTHEAST MAY SEE PERIODS OF ORGANIZED RNFL THROUGH FRI IN ASSOC WITH A COMPLEX AREA OF LOW PRES THAT MAY CONSOLIDATE OFF THE COAST BY FRI. THE RNFL FCST FOR FLORIDA IS QUITE UNCERTAIN WITH CURRENT PREFS MUCH LIGHTER THAN GFS RUNS BUT PERHAPS A LITTLE MORE GENEROUS THAN RECENT ECMWF RUNS. TEMPS WEST OF THE ROCKIES SHOULD BE NEAR TO ABOVE NORMAL WITH SOME PLUS 10-15F ANOMALIES FOR HIGHS PSBL OVER CNTRL-NRN CALIFORNIA. THE MEAN FRONTAL BNDRY SETTING UP FROM THE PLAINS EWD WILL SEPARATE NEAR TO BELOW NORMAL READINGS ACROSS THE NRN TIER FROM NEAR/ABOVE NORMAL TEMPS OVER THE SOUTH. COOLEST MAX TEMPS VERSUS NORMAL SHOULD BE OVER THE NRN HIGH PLAINS... EXTENDING A LITTLE FARTHER S/E MID-LATE PERIOD. THE SRN HIGH PLAINS/S-CNTRL PLAINS MAY REACH 10-15F ABOVE NORMAL AROUND THE MIDDLE OF THE WEEK... PSBLY APPROACHING CALENDAR DAY RECORDS AT SOME LOCATIONS. RAUSCH