EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 248 AM EDT SUN JUN 05 2016 VALID 12Z WED JUN 08 2016 - 12Z SUN JUN 12 2016 ...PATTERN OVERVIEW... THE MID-LATITUDE PATTERN WILL REMAIN AMPLIFIED WITH A BROAD NEGATIVE HEIGHT ANOMALY ENCOMPASSING THE NORTHEASTERN U.S. MID-WEEK. AS THIS SYSTEM SLIDES EASTWARD INTO THE CANADIAN MARITIMES...A DOME OF SURFACE HIGH PRESSURE WILL BUILD FROM THE MS RIVER VALLEY TOWARD THE EASTERN SEABOARD DURING THE MIDDLE OF NEXT WEEK. MEANWHILE...A SPRAWLING UPPER RIDGE INITIALLY OVER THE WESTERN HALF OF THE NATION WILL GRADUALLY NOSE EASTWARD IN RESPONSE TO LOWERING HEIGHTS ACROSS THE EASTERN PACIFIC/IMMEDIATE WEST COAST. MODELS INDICATE SPLIT FLOW OFFSHORE OF THE WESTERN U.S. WITH THE NORTHERN STREAM DOMINATING AS A CLOSED LOW SLOWLY MIGRATES THROUGH THE PACIFIC NORTHWEST ON FRIDAY/SATURDAY. ...MODEL EVALUATION/PREFERENCES... COMPARED TO RECENT DAYS...MODELS HAVE A DECENT HANDLE ON THE SYNOPTIC PATTERN...PARTICULARLY ACROSS THE WESTERN U.S. WHERE SOLUTIONS HAVE GENERALLY VARIED FROM DAY TO DAY. WHILE INDIVIDUAL SOLUTIONS VARY WITH THE DETAILS OF A DEEP UPPER TROUGH ANCHORING THE NORTHEASTERN STATES...ALL GUIDANCE AGREE ON GENERAL PLACEMENT. WHILE THE CORE OF LOWER HEIGHTS MOVES TOWARD THE HIGHER LATITUDES...RESIDUAL TROUGHING LINGERS OVER THE WESTERN ATLANTIC. MODELS CONTINUE TO ADVERTISE ADDITIONAL SHORTWAVE ENERGY TRACKING ABOVE A STAGNANT UPPER RIDGE OVER THE CENTRAL U.S. WHICH WILL HELP SUSTAIN A GENERAL TROUGH OFF THE EASTERN SEABOARD INTO NEXT WEEKEND. RECENT GFS SOLUTIONS HAVE BEEN SLIGHTLY MORE EMPHATIC AT THIS SCENARIO THAN THE FLATTER 12Z ECMWF. AFTER MANY DAYS OF STRUGGLING WITH THE SPLIT FLOW REGIME EVOLVING OVER THE EASTERN PACIFIC...THE LATEST GUIDANCE SUITE HAS SHOWN REMARKABLE IMPROVEMENTS. GENERAL AGREEMENT EXISTS IN EMPHASIZING A CLOSED UPPER LOW WITHIN THE NORTHERN STREAM WHICH SLOWLY DRIFTS EASTWARD FROM THE PACIFIC NORTHWEST TOWARD THE NORTHERN ROCKIES. WHILE THERE IS SOME VARIABILITY IN THE TIMING OF THIS FEATURE...THERE WAS ENOUGH CONFIDENCE TO INCLUDE SMALL PORTIONS OF OPERATIONAL GUIDANCE THROUGH DAY 7. THE MEDIUM RANGE PRODUCTS WERE DRIVEN BY A COMBINATION OF THE 18Z GFS/12Z ECMWF THROUGH DAY 4 WITH SLIGHTLY MORE WEIGHT TOWARD THE ECMWF GIVEN A MORE CONSISTENT SOLUTION. ALSO...SUCH A BLEND SEEMS TO HANDLE THE AREA OF LOW PRESSURE EJECTING OUT OF FL DURING THE SHORT RANGE PERIOD. THEREAFTER...CONTINUALLY ADDED MORE INFLUENCE FROM THE 18Z GEFS/12Z ECMWF ENSEMBLE MEANS WHILE STILL MAINTAINING MINUTE AMOUNTS OF THE GFS/ECMWF THROUGH DAY 7. ...WEATHER HIGHLIGHTS... GIVEN THE AMPLIFIED PATTERN AT HAND...THERE WILL BE RATHER PRONOUNCED TEMPERATURE ANOMALIES IN THE FORECAST. THE UPPER RIDGE SPANNING THE WESTERN U.S. EASTWARD TO THE MS RIVER VALLEY WILL FAVOR READINGS ROUGHLY 10 TO 15 DEGREES ABOVE NORMAL. WIDESPREAD LOW TO MID 90S ARE EXPECTED ACROSS THE GREAT PLAINS AS A LEE TROUGH STRETCHES NORTH/SOUTH ACROSS THE REGION. THE GFS/GEFS MEAN CONTINUE TO FAVOR VALUES CLOSER TO 100 DEGREES BUT WAS NOT CONFIDENT ENOUGH TO RAISE TEMPERATURES TO SUCH LEVELS. MEANWHILE...COOLER READINGS WILL PREVAIL ACROSS THE EASTERN U.S. AS A DOME OF SURFACE HIGH PRESSURE BUILDS FOR THE END OF THE WORK WEEK. THIS SHOULD SUPPORT TEMPERATURES POSSIBLY 5 TO 10 DEGREES BELOW CLIMATOLOGY. AND GIVEN THE UPPER LOW AFFECTING THE NORTHWESTERN U.S. LATER IN THE PERIOD...SIMILAR TEMPERATURE ANOMALIES ARE EXPECTED TO THROUGH THE FOLLOWING WEEKEND. REGARDING PRECIPITATION...DEPENDING ON THE TRACK OF THE TROPICAL INVEST IN THE VICINITY OF THE YUCATAN PENINSULA...CONDITIONS MAY STILL BE WET ALONG THE COASTAL CAROLINAS WITH GUSTY WINDS POSSIBLE AS WELL. OTHERWISE...A LINGERING/SHEARING FRONTAL ZONE WILL ENSURE MORE WET WEATHER FOR SECTIONS OF FL EARLY IN THE FORECAST. WITHIN THE NORTHERN STREAM...UNSETTLED WEATHER IS LIKELY OVER THE PACIFIC NORTHWEST DUE TO THE PRESENCE OF THE QUASI-STATIONARY UPPER LOW WHILE INCREASED PRECIPITATION THREATS ARE POSSIBLE OVER THE GREAT LAKES IN RESPONSE TO ANY RIDGE ROLLERS CROSSING THE REGION. RUBIN-OSTER