EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1152 AM EDT TUE MAY 03 2016 VALID 12Z FRI MAY 06 2016 - 12Z TUE MAY 10 2016 ...OVERVIEW AND GUIDANCE PREFERENCES... CLOSED LOW SEASON CONTINUES OVER THE CONUS BUT WILL BREAK DOWN NEXT WEEK INTO MUCH LESS BLOCKY FLOW. THE MODELS AND ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT OVER THE PAST FEW RUNS THAN 24-36 HRS AGO, AND A CONSENSUS BLEND SUFFICES FOR THE START OF THE PERIOD FRI-SAT. IN THE WEST, THE CUTOFF UPPER LOW WILL SLOWLY SLIDE EAST-NORTHEASTWARD THROUGH THE PERIOD AND ONLY TRAVEL FROM SOUTHERN CALIFORNIA TO THE UPPER MIDWEST OVER FIVE DAYS. 00Z ECMWF/CANADIAN WERE QUICKER THAN THE 06/00Z GFS RUNS BUT WITHIN THE ENSEMBLE SPREAD. BIGGER DIFFERENCE SEEN IN SW CANADA YESTERADAY HAVE TRENDED TOWARD THE ECMWF-LED SOLUTION OF BRINGING A TROUGH ACROSS BRITISH COLUMBIA SUNDAY WITH THE GEFS MEMBERS LAST TO SHOW THIS SOLUTION (AS THEY ARE STILL HOLDING ONTO WEAK RIDGING OR FLAT FLOW). IN THE NORTHEAST, DEPARTING LED UPPER LOW WILL EXIT INTO THE ATLANTIC ONLY TO BE REPLACED BY CANADIAN TROUGHING THAT MAY WRAP INTO ANOTHER OCCLUDED SYSTEM NEXT SUN/MON IN QUEBEC OR NORTHERN NEW ENGLAND BEFORE LIFTING NORTHEASTWARD. 00Z GFS/ECMWF/CANADIAN WERE CLOSER TO THE ENSEMBLE MEANS WHILE THE 06Z GFS WAS SLOWER AND FARTHER SOUTH. TRANSITIONED TO A BLEND OF THE 00Z ECMWF/CANADIAN/ECENS MEAN NEXT MON-TUE WHICH WAS MORE AMPLIFIED THAN THE GEFS/NAEFS MOSTLY DUE TO THE DIFFERENCES OVER W CANADA. ...WEATHER HIGHLIGHTS/THREATS... A DEEP LOW/TROUGH WORKING GRADUALLY OVER THE WEST WILL SPREAD A BROAD AREA OF RAIN AND HIGHER ELEVATION SNOWS FROM THE WEST COAST INTO THE ROCKIES... WITH LEAD RAINS DEVELOPING OVER THE CENTRAL US THIS WEEKEND INTO NEXT MONDAY. HIGHEST TOTALS ARE EXPECTED FROM FAVORED SIERRA NEVADA AND INTERMOUNTAIN WEST TERRAIN INTO PORTIONS OF CO/WY THEN OUT OVER THE PLAINS. SPC HAS A 15% RISK AREA OF SEVERE STORMS ON SATURDAY AHEAD OF THE COLD FRONT FROM W TEXAS NORTHWARD TO WESTERN KANSAS AND EASTERN COLORADO. TEMPERATURES WITH THE SYSTEM ARE EXPECTED TO BE 10-15F BELOW AVERAGE UNDER THE UPPER LOW. RIDGING ALOFT AHEAD OF THIS SYSTEM IS EXPECTED TO SUPPORT LEAD WARMING SPREADING FROM THE CENTRAL/HIGH PLAINS FRIDAY INTO THE SOUTHEAST BY SUNDAY AS THE COLD FRONT PUSHES THROUGH THE MID-ATLANTIC. EAST COAST/WESTERN ATLANTIC SURFACE LOWS/FRONTS WILL GENERALLY SUPPORT COOL AND UNSETTLED WEATHER OVER THE EAST FRIDAY INTO SATURDAY AHEAD OF THE NEXT FRONT AND DEEEPENING SFC LOW SUNDAY. MUCH OF THE PRECIPITATION IS EXPECTED OVER THE MID-ATLANTIC/NEW ENGLAND STATES FRIDAY-SUNDAY WITH WRAP-AROUND LIGHER PRECIP FOR NEXT MONDAY IN NORTHERN NEW ENGLAND BUT CLEARING TO THE SOUTH. FRACASSO/ROTH