EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1242 AM EDT FRI MAY 16 2014 VALID 12Z MON MAY 19 2014 - 12Z FRI MAY 23 2014 ...OVERVIEW AND GUIDANCE EVALUATION/PREFERENCES... IT STILL SEEMS EVIDENT THAT MODELS AND ENSEMBLES CONTNIUE TO SHOW BETTER THAN AVERAGE AGREEMENT AND CONTINUITY FOR THE AMPLIFIED AND SLOWLY EVOLVING PATTERN EXPECTED DURING THE PERIOD. A TROUGH NEAR THE WEST COAST SHOULD STEADILY AMPLIFY WITH AN EMBEDDED UPR LOW SETTLING OVER/NEAR THE GREAT BASIN/SOUTHWEST DURING THE MID AND LATER PART OF NEXT WEEK. MEANWHILE AN UPPER LOW CROSSING THE NORTHEAST EARLY NEXT WEEK SHOULD LINGER OFF THE COAST INTO WED-FRI...SLOWLY REACHING THE CANADIAN MARITIMES. BETWEEN THESE FEATURES A RIDGE BUILDS TO THE MS VALLEY WITH A CLOSED HIGH FORMING NEAR THE LOWER MS VALLEY NEXT WED-FRI. GOOD CLUSTERING DAYS 3-5 MON-WED LEADS TO STARTING WITH A COMPOSITE BLEND OF THE 12 UTC GFS/ECMWF/UKMET AND GFS/ECMWF ENSEMBLE MEANS. SWITCHED TO A 50-50 BLEND OF THE COMPATABLE GFS/ECMWF ENSEMBLES DAYS 6/7 THU/FRI IN A PERIOD WITH SLOWLY INCREASING FORECAST SPREAD AT SMALL-MID SCALES. THIS SOLUTION OFFERS EXCELLENT WPC MASS FIELD CONTINUITY IN A PATTERN WITH OVERALL ABOVE AVERAGE PREDICTABILITY. ...SENSIBLE WEATHER HIGHLIGHTS... THE AMPLIFYING WRN TROUGH AND DOWNSTREAM FLOW SPREADS MOISTURE AND COOLING TEMPS ACROSS THE WEST COAST...GREAT BASIN...ROCKIES...N-CENTRAL PLAINS. COMBINATION OF DYNAMICS ALOFT/SLOWING OF THE UPPER SYSTEM AND TERRAIN ENHANCEMENT FROM THE HIGH PLAINS WWD MAY SUPPORT SOME MODERATE-HEAVY PRECIPITATION...INCLUDING HIGHER ELEVATION SPRING SNOWS. THE N-CENTRAL US NRN TIER MAY ALSO SEE SOME HEAVIER RAINS MON-WED AS A MID LEVEL TROUGH TRACKS ALONG/N OF THE CANADIAN BORDER. SOME HEAVY SHOWERS/BOOMERS MAY ALSO DEVELOP FARTHER SEWD AS WAVY FRONTAL ZONE SPREADS MOISTURE INTERCEPT FOCUS TOWARD THE GREAT LAKES/OH VALLEY/MID-ATLANTIC. THE UPPER LOW AFFECTING THE NORTHEAST SUPPORTS COOLED TEMPS AND SOME WRAPPED RAINS. GREATEST ANOMALIES FOR TEMPS SHOULD BE OVER THE SRN HALF OF THE PLAINS WITH LOCATIONS FROM WRN TX INTO KS SEEING THE BEST POTENTIAL FOR HIGHS OF 10-20F ABOVE NORMAL FOR ONE OR MORE DAYS IN THE MON-WED TIME FRAME... PSBLY APPROACHING DAILY RECORD VALUES. SOME OF THIS WARMTH WILL SPREAD EWD WITH TIME THOUGH WITH LESSER ANOMALIES. DAYTIME HIGHS UPWARDS TO 10F BELOW NORMAL OVER THE WEST SHOULD BE MORE LOCALIZED AND UNDER THE GREAT BASIN CENTERED UPPER LOW. SCHICHTEL