EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 101 AM EDT WED MAY 06 2015 VALID 12Z SAT MAY 09 2015 - 12Z WED MAY 13 2015 ...OVERVIEW AND GUIDANCE PREFERENCES... RIDGE/TROUGH/RIDGE PATTERN OVER NW CANADA/FOUR CORNERS/NORTHEAST TO START THE PERIOD THIS SAT WILL SHIFT EASTWARD BY MIDWEEK NEXT WEEK. THIS WILL LEAD TO TROUGHING NEAR BOTH COASTS AND RIDGING IN THE PLAINS. THE MODELS AND ENSEMBLES HAVE HAD A PRETTY GOOD HANDLE ON THE SETUP THE PAST SEVERAL DAYS... WITH EXPECTED DETAIL DIFFERENCES DOMINANT THROUGH ABOUT 132HRS. THE 12/18Z RUNS SHOWED A LITTLE LESS CLUSTERING RIGHT FROM SAT/D3 ONWARD... BUT ARE STILL WITHIN REASON. HOWEVER... THE ECMWF/ECENS MEAN OFFERED A BETTER BLEND FOR SAT-MON/D3-5 OVER THE INCLUSION OF THE GFS/GEFS MEAN... ESPECIALLY WITH THE HANDLING OF THE INCOMING PAC NW TROUGH BUT ALSO THE NEXT UPPER LOW TO EXIT COLORADO... WHERE THE 12Z GFS WAS QUITE SLOW... AND LASTLY THE PESKY LOW PRESSURE OFF THE SE COAST. ANY MODEL BECAME SUSPECT BY NEXT TUE/WED AS LOW PRESSURE SHOULD MOVE EASTWARD THROUGH THE GREAT LAKES/NORTHEAST PER THE ECENS MEMBERS OR PERHAPS JUST NORTH OF THE OHIO VALLEY PER THE GEFS. OPTED TO PUT MORE WEIGHT IN THE MORE NORTHERLY TRACK SINCE THAT IS WHERE MOST OF THE DETERMINISTIC RUNS HAVE LIED. TRACK OF THE POTENTIALLY SUBTROPICAL LOW OFF/NEAR THE COAST IS STILL A BIT UNCERTAIN... BUT SHOULD MEANDER AROUND THE NC/SC BORDER SAT/SUN BEFORE WASHING OUT. ...SENSIBLE WEATHER HIGHLIGHTS... THE COOLER THAN AVERAGE WEST AND WARMER THAN AVERAGE EAST PATTERN WILL SHIFT EASTWARD IN TIME THIS PERIOD. RECORD MAX OR HIGH MIN TEMPS MAY BE POSSIBLE AHEAD OF THE SFC FRONT. PRECIPITATION WILL FOCUS AROUND AND DOWNSTREAM OF THE EXITING CLOSED LOW FROM THE FOUR CORNERS REGION -- CENTRAL ROCKIES/PLAINS SOUTHWARD AND THEN NORTHEASTWARD TOWARD THE GREAT LAKES. GEFS REFORECAST DATA SHOWS NE COLORADO INTO WESTERN AND CENTRAL NEBRASKA IN THE 99.5 PERCENTILE -- M-CLIMATE RELATIVE -- WHICH LINES UP WITH THE ECMWF AND ECENS MEAN RELATIVE MAX QPF AMOUNTS. NEXT TROUGH INTO THE PAC NW EARLY NEXT WEEK WILL BRING SOME SHOWERS TO WA/OR/ID AND NORTHERN CA/NV. ALONG THE CAROLINA COAST... MODELS CONTINUE TO BE ALL OVER THE PLACE FROM SEVERAL TENTHS OF AN INCH OF RAIN TO SEVERAL INCHES OF RAIN... SOME OFFSHORE AND SOME INLAND. WILL CONTINUE TO BE SUSPICIOUS OF ANY ONE RUN AND WILL FOLLOW THE ENSEMBLES UNTIL THIS IS BETTER RESOLVED... PROBABLY IN THE SHORT RANGE. FRACASSO