ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 252 PM EST WED FEB 15 2017 VALID 12Z SUN FEB 19 2017 - 12Z THU FEB 23 2017 DURING THE UPCOMING PERIOD...THE HIGH LATITUDES WILL REMAIN MORE BLOCKED IN NATURE WITH A NEGATIVE HEIGHT ANOMALY LINGERING OVER THE NORTHERN HALF OF AK WHILE BROAD RIDGING EXTENDS OVER SIBERIA. UNDERNEATH THIS MORE STAGNANT FLOW...SYSTEMS WILL BE MORE PROGRESSIVE IN NATURE AS A SERIES OF SHORTWAVES TRACK FROM THE NORTH-CENTRAL PACIFIC TO THE GULF OF AK. A PAIR OF FAIRLY SIGNIFICANT UPPER LOWS ARE EXPECTED TO CROSS THE WESTERN ALEUTIANS DURING THE EARLY/MIDDLE PART OF NEXT WEEK. THESE ARE RATHER WRAPPED UP SYSTEMS WITH POTENT SURFACE CYCLONES LEADING TO IMPRESSIVE PRESSURE GRADIENTS. MODELS HAVE GENERALLY BE CONSISTENT IN DEVELOPING ROBUST LOW CENTERS BUT A FEW ODD RUNS HAVE COME IN WEAKER WHICH DO LOOK A BIT SUSPICIOUS. THERE IS SOME NORTH/SOUTH SPREAD BUT DID WANT TO INCORPORATE ENOUGH DETERMINISTIC INFLUENCE TO CAPTURE THE EXPECTED WIND FIELDS. AS SUCH...CHOSE TO DEDICATE AT LEAST HALF OF THE MODEL SPREAD TO THE 12Z GFS/00Z ECMWF THROUGH ROUGHLY DAY 5 WHILE THE REMAINING CONTRIBUTIONS WERE GIVEN TO THE 00Z ECMWF/NAEFS ENSEMBLE MEANS. TOWARD THE LATTER HALF OF THE PERIOD...WENT WITH AN EQUAL SPLIT OF THE AFOREMENTIONED ENSEMBLE MEANS GIVEN GROWING SPREAD ACROSS THE MAP DOMAIN. BY EARLY/MID NEXT WEEK...THERE SHOULD BE A MARKED WARM UP EXPECTED OVER WESTERN AK AS TEMPERATURES RISE AROUND 20 TO 30 DEGREES FROM THEIR READINGS OVER THE WEEKEND. THERE WILL ALSO BE ACCOMPANIED INCREASE IN WIND GIVEN THE STRONG PRESSURE GRADIENT STRETCHING OVER THE ALEUTIANS. FURTHER...AN UPTICK IN LOW-LEVEL MOISTURE FLUXES WILL INCREASE THE THREAT FOR PRECIPITATION FROM WEST TO EAST. RUBIN-OSTER