EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 138 AM EDT MON MAR 30 2015 VALID 12Z THU APR 02 2015 - 12Z MON APR 06 2015 ...WARMEST TEMPERATURES OF THE YEAR LIKELY FOR THE NORTHEAST LATER THIS WEEK... ...OVERVIEW... MEDIUM RANGE PERIOD IS FORECAST TO TRANSITION TOWARD A DIFFERENT PATTERN THAN SEEN IN THE PAST SEVERAL MONTHS WITH RIDGING CENTERED OVER MEXICO. AN UPPER LOW CIRCLING AROUND HUDSON BAY WILL LOWER HEIGHTS IN THE NORTHEAST NEXT WEEKEND. INITIAL TROUGHING IN THE WEST WILL PUSH ACROSS THE CONUS AS A SFC COLD FRONT THU-SAT. BY NEXT WEEKEND... AN UPPER LOW IS STILL FORECAST TO DROP SLOWLY SOUTHEASTWARD OUT OF THE GULF OF ALASKA AND SETTLE INTO THE PAC NW BY NEXT MON 4/6. ...GUIDANCE PREFERENCES... TREND IN THE ENSEMBLE GUIDANCE OVER THE PAST FEW RUNS HAVE BEEN TOWARD A MORE ECMWF/ECENS MEAN SOLUTION IN THE PAC NW -- THAT IS... SLOWER WITH THE CLOSED UPPER LOW -- BUT A BIT MORE OF A COMPROMISE SOLUTION IN THE EAST. SPREAD AMONG THE MEMBERS HAS DECREASED TO NO WORSE THAN AVERAGE AND THE DETERMINISTIC MODELS MOSTLY STAY WITHIN THEIR ENSEMBLE BOUNDS. GFS REMAINS QUICKER WITH THE SFC FRONT THROUGH THE NORTHEAST/MID-ATLANTIC FRI COMPARED TO THE OTHER GUIDANCE.... AND SLOWER IN THE SOUTHERN PLAINS AS IT EMPHASIZES THE SOUTHERN STREAM OVER THE NORTHERN STREAM. BETTER AGREEMENT/CONTINUITY LIES WITH THE ECMWF/UKMET AND ECENS MEAN CLUSTER. FOR THE WEEKEND INTO MONDAY... TRACK/EVOLUTION OF PAC NW UPPER LOW IS DEPENDENT UPON UPSTREAM FLOW OVER ALASKA... WHICH SHOWS A LOT OF ENSEMBLE SPREAD. RIDGING MAY GET SQUASHED OVER ALASKA DEPENDING ON FURTHER UPSTREAM CLOSED LOW. GIVEN THE UNCERTAINTY... TRENDED TOWARD A BLEND BETWEEN THE NAEFS AND ECENS MEAN AS THE GEFS REMAINS JUST A BIT QUICKER. ...SENSIBLE WEATHER HIGHLIGHTS... QUASI-ZONAL FLOW WILL SUPPORT CHANGEABLE TEMPERATURES... MODULATED BY THE SFC COLD FRONT THU-SAT IN THE CENTRAL/EASTERN/SOUTHERN STATES. OVERNIGHT MIN TEMPS WILL BE ON THE MILD SIDE IN ADVANCE OF THE COLD FRONT -- ABOVE FREEZING THROUGH MOST OF NEW ENGLAND AFTER A CHILLY START THURSDAY MORNING IN MAINE. 70S MAY ADVANCE PAST THE MASON-DIXON LINE ON FRIDAY IN WHAT COULD BE THE WARMEST TEMPERATURE IN OVER FOUR MONTHS FOR MUCH OF THE MID-ATLANTIC/NORTHEAST. POST-FROPA TEMPS WILL RETURN TO BELOW AVG READINGS BY ABOUT 5-15F. TEMPS IN THE PAC NW ARE FORECAST TO BE BELOW AVG THANKS TO INCOMING TROUGHING... PUSHING THE ABOVE AVG TEMPS TO ALONG/EAST OF THE DIVIDE INTO THE PLAINS. PRECIPITATION SHOULD BE FAIRLY WIDESPREAD ALONG AND AHEAD OF THE FRONT IN THE EAST LATER THIS WEEK... FOCUSED ESPECIALLY IN THE OHIO VALLEY. ONCE HIGH PRESSURE MOVES IN BEHIND THE FRONT... RETURN FLOW FROM THE GULF SHOULD HELP YIELD MORE RAIN IN TEXAS AND THE LOWER MS VALLEY. BACK WEST... UPPER LOW AND ASSOCIATED SFC FRONT WILL SPREAD RAIN AND MOUNTAIN SNOW FROM COASTAL WA/OR AND NORCAL INLAND... BUT THIS DEPENDS ON HOW QUICKLY THE SYSTEM MOVES EAST. FRACASSO