ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 326 PM EST SUN FEB 26 2017 VALID 12Z THU MAR 02 2017 - 12Z MON MAR 06 2017 AN IMPRESSIVE UPPER RIDGE WILL REMAIN THE DOMINANT FEATURE INFLUENCING THE PATTERN ACROSS AK DURING THE FIRST WEEK OF MARCH. RECENT GFS SOLUTIONS ADVERTISE 500-MB HEIGHT ANOMALIES IN THE 3 TO 4 SIGMA ABOVE AVERAGE RANGE. THIS DOMINANT SYSTEM IS FORECAST TO BE CENTERED OVER THE BERING SEA AND INTO SIBERIA WHILE GRADUALLY SLIDING WESTWARD IN TIME. TO THE EAST OF THE POSITIVE HEIGHT ANOMALY...THE HIGHLY MERIDIONAL PATTERN WILL ALLOW A SERIES OF SHORTWAVES TO DIVE SOUTHWARD ACROSS THE WESTERN HALF OF MAINLAND AK AND INTO THE NORTHEAST PACIFIC. THESE SYSTEMS SEEM TO SQUEEZE BETWEEN THE MEAN UPPER RIDGE TO THE WEST AND A CLOSED LOW LINGERING ACROSS THE ARCTIC OCEAN. WHILE THERE ARE GENERAL DIFFERENCES IN THE DETAILS WITH THIS PATTERN...THE LONGWAVE PATTERN IS REASONABLY AGREED UPON. THIS IS IN STARK CONTRAST OF WHAT WAS SEEN IN THE PAST FEW DAYS WHICH SAW DETERMINISTIC SOLUTIONS AT ODDS WITH ONE ANOTHER. THE BIGGEST DIFFERENCE NOTED WAS TOWARD THE END OF NEXT WEEKEND WHERE SPREAD BECAME EVIDENT ALONG THE SOUTHWEST FLANK OF THE LONGWAVE TROUGHING. THIS PRIMARILY AFFECTED THE POSITION OF THE UPPER TROUGH ACROSS THE NORTHEAST PACIFIC ON DAY 7/8...MARCH 5/6 WHERE THE 12Z GFS WAS WEST OF THE MODEL CONSENSUS. GIVEN THE STRONGER DETERMINISTIC AGREEMENT...WAS ABLE TO MAINTAIN SOME FRACTION OF SUCH MODELS THROUGH DAY 6/SATURDAY. THE GENERAL APPROACH WAS TO UTILIZE 60 PERCENT OF THE 00Z ECMWF SUITE WITH THE REMAINING PORTION OF THE BLEND DEDICATED TO THE 12Z GFS/06Z GEFS MEAN. EACH DAY LOWERED THE INFLUENCE OF THE 12Z GFS/00Z ECMWF AS UNCERTAINTIES IN THE FORECAST DETAILS BEGAN TO INCREASE. THE RESULTANT PATTERN WILL FAVOR RATHER COLD TEMPERATURES ACROSS THE STATE GIVEN THE INFLUENCE OF SURFACE HIGH PRESSURE ON THE SENSIBLE WEATHER. SOME RATHER COLD OVERNIGHT LOWS ARE FORECAST ACROSS NORTHERN/EASTERN AK WITH SOME MINIMA GOING BELOW -40 DEGREES DURING THE PERIOD. IT SHOULD ALSO BE QUITE BREEZY AT TIMES...PARTICULARLY EARLY IN THE FORECAST PERIOD WHERE MODERATE EAST-SOUTHEASTERLY WINDS AFFECT THE WESTERN/CENTRAL ALEUTIANS. IN TERMS OF PRECIPITATION...THE INFLUENCE OF CONTINENTAL ARCTIC AIR MASSES SHOULD KEEP MUCH OF MAINLAND AK DRY ALTHOUGH THE 12Z GFS WAS A TAD WETTER WITH THE SYSTEM DIVING THROUGH WESTERN AK ON FRIDAY/SATURDAY. OTHERWISE...THE HIGHEST PROBABILITIES FOR PRECIPITATION REMAIN OVER SOUTHEASTERN AK GIVEN THE PERSISTENT NEGATIVE HEIGHT ANOMALIES IN THE NORTHEAST PACIFIC. RUBIN-OSTER