EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1153 AM EDT SAT MAY 06 2017 VALID 12Z TUE MAY 09 2017 - 12Z SAT MAY 13 2017 ...PATTERN OVERVIEW AND GUIDANCE EVALUATION... A PERSISTENT OMEGA BLOCK WILL BE IN PLACE THROUGH THE EXTENDED PERIODS-- WITH A RIDGE WEDGED BETWEEN CLOSED LOWS OVER THE WEST AND NORTHEAST. ADDITIONALLY, THE EASTERN LOW WILL TRANSITION TO A REX BLOCK BY EARLY WEDNESDAY MORNING (DAY 4) WITH SOME OF THE SOLUTIONS SHOWING THE LOW SPLITTING BY THURSDAY (DAY 5). SHOULD THIS OCCUR ANOTHER LOBE OF VORTICITY WILL ROTATE THROUGH SOUTHERN CANADA AND BACK THROUGH THE GREAT LAKES LATER IN THE WEEK (FORCED BY A STRONG UPPER HIGH IN NORTHERN QUEBEC). MEANWHILE THE UPPER LOW OVER SOUTHERN CALIFORNIA/SOUTHWEST WILL ADVANCE EASTWARD INTO THE SOUTHERN PLAINS, POSSIBLY LATCHING ON TO THE AFOREMENTIONED FEATURE BY THE END OF THE WEEK AS IS CROSSES THROUGH THE CENTRAL U.S. RIDGING WILL LARGELY STAY IN PLACE OVER THE HIGH PLAINS AND ACROSS THE SOUTHEAST. ANOTHER LOW WILL DIG SOUTHEAST THROUGH GULF OF ALASKA TO THE PACIFIC NORTHWEST BY THIS COMING WEEKEND. THE 00Z/06Z RUNS OF THE GFS SLOWED THE PROGRESSION OF THE LOW OVER THE SOUTHWEST, WHEREAS THE 00Z ECWMF WAS A BIT FASTER. OVERALL A CONSENSUS BLEND CONTINUES TO BE FAVORED. ...WEATHER HIGHLIGHTS... GENERALLY BELOW AVERAGE TEMPERATURES NEAR THE TRACK OF A GIVEN UPPER LOW WITH ABOVE AVERAGE TEMPERATURES CONFINED TO THE INTERIOR NORTHWEST (AHEAD OF THE FRONT) INTO THE HIGH PLAINS AND ALSO THROUGH THE SOUTHEAST UNTIL THE FRONT COMES THROUGH NEXT SATURDAY. PRECIPITATION WILL FOCUS ALONG THE STATIONARY FRONTAL BOUNDARY THROUGH THE CENTRAL PLAINS IN ADDITION TO NEAR THE UPPER LOW EXITING THE SOUTHWEST STATES. ENSEMBLES SHOW THE MAX QPF ALONG AN E-W LINE FROM COLORADO INTO KANSAS/MISSOURI TUESDAY-THURSDAY THEN EXTENDING EASTWARD AS THE THEN OPEN TROUGH SLIDES EASTWARD. SEVERE WEATHER IS POSSIBLE IN THE SOUTHERN PLAINS -- SEE THE LATEST SPC OUTLOOKS. LIGHTER BUT RATHER PERSISTENT WRAP AROUND SHOWERS WILL PLAGUE THE NORTHEAST FOR MUCH OF THE PERIOD, THOUGH WITH SOME BREAKS IN THE WET WEATHER. THE PAC NW WILL SEE AN INCREASE IN PRECIPITATION (MOSTLY RAIN BUT HIGHER ELEVATION SNOW) FRIDAY INTO SATURDAY. FINALLY, THE MID-ATLANTIC MAY BE THE FOCUS FOR MORE RAIN NEXT WEEKEND AS THE SFC LOW EXITS THE COAST. CAMPBELL/FRACASSO