EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 251 AM EDT MON JUL 20 2015 VALID 12Z THU JUL 23 2015 - 12Z MON JUL 27 2015 ...PATTERN OVERVIEW...MODEL/UNCERTAINTY ASSESSMENT...SENSIBLE WEATHER HIGHLIGHTS... GUIDANCE CONTINUES TO BE IN GOOD MEDIUM-LARGE SCALE AGREEMENT WITH THIS UNUSUAL EAST PACIFIC FLOW PATTERN AND THE PROGRESSION OF MAJOR SYNOPTIC-SCALE FEATURES ACROSS CANADA AND INTO THE LOWER 48 THAT WILL FOCUS MOISTURE AND CONVECTIVE POTENTIAL...ALBEIT WITH SOME LINGERING TIMING DIFFERENCES. UNSEASONABLY ORGANIZED DRY/COOLING FRONTS SAG DOWN ACROSS THE LOWER 48 AND INTERACT WITH SRN STREAM SYSTEM ENERGIES TRAVERSING MID-LOWER LATITUDES OUT OF THE WEST AND MOST NOTABLY FIRING CONVECTION FROM THE N-CENTRAL US SEWD INTO THE SERN US AROUND THE MOIST PERIPHERY OF A HOT S-CENTRAL US CENTERED MID-UPPER LEVEL RIDGE. HOWEVER...SMALL SCALE VARIANCE/LOCAL CONVECTIVE FOCUS REMAINS MORE UNCERTAIN. ACCORDINGLY...WPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS HAVE BEEN PRIMARILY DERIVED FROM THE 12 UTC NAEFS/ECMWF ENSEMBLE MEANS TO MITIGATE SMALLER SCALE VARIANCE. MANUAL FORECASTER ADJUSTMENTS WERE APPLIED TO MAINTAIN MAX WPC CONTINUITY/CONSISTENCY. SCHICHTEL