ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 206 PM EDT THU MAR 19 2015 VALID 12Z MON MAR 23 2015 - 12Z FRI MAR 27 2015 UPPER PATTERN FROM ASIA INTO THE PACIFIC IS FORECAST TO TREND TOWARD MORE AMPLIFICATION... STEMMING FROM VERY STRONG RIDGING OVER CHINA EARLY NEXT WEEK THAT WILL FAVOR DIGGING TROUGHING ALONG/EAST OF 180 AND THE DATELINE. DOWNSTREAM AFFECT WILL CONTINUE THROUGH NORTH AMERICA WITH RIDGING FORECAST TO STRENGTHEN OVER THE WESTERN SHORE AND TROUGHING AROUND 100W. ENSEMBLES HAVE TRENDED TOWARD BETTER AGREEMENT OVER THE PAST FEW RUNS WITH THE GEFS MEMBERS REMAINING A BIT QUICKER AND TO THE NORTH OF THE ECMWF AND CANADIAN ENSEMBLES. ONGOING PREFERENCE LIES WITH THE SLOWER EVOLUTION OF THE PATTERN VIA THE ECMWF ENSEMBLE MEAN THOUGH A MINORITY WEIGHTING OF THE GEFS AND NAEFS MEANS WAS USED AS A BASE TO THE FORECAST. OPERATIONAL MODELS CONTINUE TO STRUGGLE WITH THE SPECIFICS IN THE FORECAST BUT HAVE WAVERED AROUND THE ENSEMBLE MEANS OVER THE PAST FEW CYCLES SO ANY ONE RUN CANNOT REALLY BE DISCOUNTED COMPLETELY. SUCH A STRONG SIGNAL FOR INCREASED RIDGING BY THE END OF NEXT WEEK SHOULD BASICALLY HALT/SHEAR APART THE LEAD SYSTEM OF INTEREST. ENSEMBLES TEND TO BE MORE CORRECT IN FORECASTING STRONG RIDGING COMPARED TO STRONG TROUGHING AND GIVEN THE UPSTREAM PATTERN WOULD NOT BE SURPRISED TO SEE A TREND TOWARD MORE HEIGHT RISES IN W CANADA IN SUCCESSIVE RUNS. DOES NOT APPEAR TO BE A SPLIT RIDGE LIKE THE CURRENT SETUP BUT RATHER A MORE COHESIVE FULL LATITUDE RIDGE THAT SHOULD ACT AS A WALL OVER THE PANHANDLE. TEMPERATURES SHOULD AVERAGE NEAR OR ABOVE NORMAL... ESPECIALLY THROUGH THE INTERIOR. PRECIPITATION SHOULD FOCUS ALONG SOUTHERN CENTRAL AREAS WITH SOUTHEASTERLY FLOW AS WELL AS THROUGH THE PANHANDLE WITH THE APPROACHING BUT WEAKENING FRONT. FRACASSO