EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1259 AM EDT SUN JUL 10 2016 VALID 12Z WED JUL 13 2016 - 12Z SUN JUL 17 2016 GENERAL FLOW PATTERN AND MODEL CHOICES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ THE GUIDANCE GENERALLY AGREES ON QUASI-ZONAL FLOW ACROSS THE NORTHERN STATES WITH A SUBTROPICAL RIDGE DOMINATING THE PATTERN DOWN SOUTH. THE LARGEST WRINKLE IN THE FORECAST REMAINS HOW STRONG, AND WHETHER OR NOT, A CLOSED LOW WOULD BE MOVING THROUGH SOUTHWEST CANADA AND THE PACIFIC NORTHWEST MID TO LATE PERIOD. THE 00Z GFS TRENDED STRONGLY TOWARDS THE 12Z ECMWF IDEA OF A MORE FORMIDABLE SYSTEM, THOUGH EVEN THE 12Z ECMWF ENSEMBLE MEAN LOST SUPPORT FOR IT BY NEXT SUNDAY. TO SLOWLY TREND IN THIS DIRECTION, FOR THE MID-LEVEL AND SURFACE PRESSURE/WIND PATTERN, STARTED WITH A COMPROMISE OF THE 12Z UKMET/18Z GFS/12Z ECMWF. LATE IN THE PERIOD, SWITCHED TO A COMPROMISE OF THE 18Z GFS/12Z ECMWF/12Z BIAS-CORRECTED NAEFS MEAN/12Z ECMWF ENSEMBLE MEAN COMPROMISE. THE TEMPERATURE/RAIN CHANCES/CLOUD COVER/DEW POINT PATTERN WAS MORE ENSEMBLE MEAN HEAVY TO DEAL WITH THE GREATER UNCERTAINTY INHERENT IN THESE FIELDS. FOR THE DAYS 4-7 QPF, USED A COMPROMISE OF THE 18Z GFS/00Z GFS/12Z ECMWF SOLUTIONS. WEATHER HIGHLIGHTS/THREATS ~~~~~~~~~~~~~~~~~~~~~~~~~~ OTHER THAN THE TYPICAL SUMMER HEAT ACROSS THE SOUTHERN PORTION OF THE COUNTRY, HEAVY RAINS APPEAR SLATED FOR AREAS IN AND NEAR MISSOURI THIS PERIOD -- PARTICULARLY INTO SATURDAY -- WHERE CLOSE TO 5" AREAL AVERAGE HAS BEEN FORECAST AND LOCALLY HIGHER AMOUNTS ARE POSSIBLE. SYNOPTICALLY, THE SHOW-ME STATE IS NEAR THE SOUTHERN FRINGE OF THE WESTERLIES UNTIL NEXT SUNDAY, WHEN TROUGHING ACROSS THE NORTHWEST FINALLY SHIFTS THE AXIS OF POTENTIAL CONVECTIVE SYSTEMS THAT TEND TO FORM ON THE NORTH SIDE OF THE SUBTROPICAL RIDGE MORE NORTHWARD MORE TOWARDS THE UPPER MIDWEST/NORTHERN PLAINS. ROTH