EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1152 AM EDT TUE JUN 14 2016 VALID 12Z FRI JUN 17 2016 - 12Z TUE JUN 21 2016 ...PATTERN OVERVIEW... A BUILDING AND EXPANDING UPPER-LEVEL RIDGE EXTENDING FROM THE DESERT SW TO THE MID SECTION OF THE COUNTRY WILL BE THE MAIN DOMINANT FEATURE DURING THE MEDIUM RANGE PERIOD. THE AREAS OF CONCERN WILL BE ON THE NORTHEAST SIDE OF THIS RIDGE INTO THE NERN QUAD OF THE COUNTRY AND HOW UPPER DYNAMICS EVOLVE ALONG OR JUST OFFSHORE OF THE EASTERN SEABOARD FROM SAT ONWARD. EXPECT A PARTIAL RING OF FIRE TO THE NORTH AND EAST OF THE UPPER RIDGE... WHILE POSSIBLY RECORD BREAKING HEAT WILL BE POSSIBLE FROM THE SOUTHWEST TO THE CENTRAL/SOUTHERN PLAINS. ...MODEL PREFERENCES/UNCERTAINTY ASSESSMENT... WPC ATTEMPTED TO KEEP CONTINUITY FROM OVERNIGHT... THE MEAN ANOMALOUS RIDGE EXTENDING SW TO NE FROM THE SOUTHWEST TO THE MIDWEST... A PARTIAL PERSISTENT WEAKNESS OVER THE NW QUAD OF THE COUNTRY... A COUPLE OF FRONTAL ZONES CLIPPING THE NORTHERN TIER OF THE COUNTRY AND ALLOWING SOME RIDGING IN ADVANCE TO PROPAGATE FROM THE UPPER MS VALLEY TO THE NORTHEAST. THE BIGGEST UNCERTAINTY CONTINUES TO BE ALONG THE EAST COAST INTO THE ATLANTIC WITH SPLIT FLOW POSSIBLY PHASING TO CREATE A LARGE CUTOFF SYSTEM OR OVERALL A WEAKNESS ALONG THE SOUTHEAST COAST. THOUGH THE ECMWF HAS BEEN CONSISTENT... THE INTENSITY OF THE CLOSED CUTOFF LOW RETROGRADING TOWARD THE MID-ATL COAST HAS DECREASED IN INTENSITY BUT HAS SUPPORT FROM THE OPERATIONAL CANADIAN. THE GFS THOUGH NOT AS CONSISTENT CONTINUES TO ADVERTISE NO PHASING AND THE SRN STREAM UPPER DYNAMICS DIVING TO THE SOUTHEAST COAST AND A LOW RETROGRADING INLAND AND THIS SCENARIO SEEMS MUCH MORE CLIMATOLOGICALLY PLAUSIBLE. THE MEANS OF THE GFS... ECMWF AND CANADIAN ALL DOWNPLAY THE SPECIFICS FOR THE OPERATIONAL SOLUTIONS AND SUGGEST A GENERAL ELONGATED WEAKNESS THROUGH THE FCST PERIOD. WPC FOLLOWED A BLEND OF THE EC MEAN WITH THE NAEFS TO HOPEFULLY CAPTURE THIS OVERALL WEAKNESS AND UNCERTAINTY OFF/ALONG THE EASTERN SEABOARD. ...WEATHER HIGHLIGHTS... THE MAIN AND MOST SIGNIFICANT HIGHLIGHT WILL BE WITH TEMPS... TEMPERATURES SHOULD BE 'WELL ABOVE' AVERAGE ACROSS MUCH OF SOUTHWEST QUARTER OF THE COUNTRY AND CENTRAL/SOUTHERN PLAINS...WITH POTENTIALLY RECORD BREAKING HIGH TEMPERATURES FORMING BENEATH THIS DEEP-LAYERED ANTICYCLONE AND RIDGE AXIS ANCHORED ACROSS A LARGE PORTION OF THE MID-CONTINENTAL NORTH AMERICA. THE MAIN ENHANCED QPF FRI THROUGH SAT WILL BE ACROSS THE UPPER MIDWEST WITH A SLOW BUT MOVING FRONTAL ZONE... FROM ERN MT THROUGH ND INTO MN. A SHORT WAVE DIVING THROUGH THE MID-ATL TO CAROLINA COAST WITH AN INVERTED TROUGH AXIS EXTENDING BACK WEST OF THE APPALACHIANS INTO OH/WRN PA... WHICH COULD ENHANCE RAINFALL. FINALLY ALONG THE IMMEDIATE GULF COAST/INLAND TO FL WITH A FRONT REACHING THE REGION BEFORE STALLING. A SURFACE LOW OR COASTAL WAVE---WILL HAVE TO BE MONITORED ---AND LIKELY GOING TO BE A CHALLENGE FOR QPF AT SOME POINT NEXT WEEKEND VERY NEAR THE DELMARVA PENINSULA...OUTER BANKS AND PIEDMONT. IN ANY EVENT...LOOKS TO BE A COOLER AND BUT LOCALLY WET PATTERN FOR THE SOUTHEAST. THEN ON SUN THROUGH MON... EXPECT AN UNSETTLED PERIOD OF CONVECTION/RAIN FROM THE UPPER MIDWEST TO THE GREAT LAKES/OH VALLEY AND... WHILE ENHANCED SEA BREEZE ACTIVITY WILL BE POSSIBLE NEAR THE GULF COAST STATES AND FL. CONCERNING THE LOW/WEAKNESS OFFSHORE OF THE EAST COAST SUN/MON... KEPT A STALLED FRONTAL ZONE NEAR THE SOUTHEAST COAST AND INVERTED SURFACE TROUGH UP NORTH JUST OFFSHORE OF THE MID-ATL REGION... WOULD THINK ISOLATED TO SCATTERED SHOWERS/STORMS WILL BE POSSIBLE BUT NOTHING AS CONCENTRATED AS SOME OF THE OPERATIONAL SOLUTIONS. MUSHER