ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 148 PM EDT MON MAR 10 2014 VALID 12Z FRI MAR 14 2014 - 12Z TUE MAR 18 2014 ...ACTIVE WEATHER PATTERN FOR ALASKA... THE ALASKAN MEDIUM RANGE LARGER SCALE FLOW PATTERN IS EXPECTED TO BE HIGHLIGHTED ALOFT BY AN AMPLIFIED AND COOL/UNSETTLING MEAN TROUGH FROM THE BERING SEA THROUGH THE ALEUTIANS AND SEWD ACROSS SWRN AK AND THE GULF OF AK...WITH POTENT PIECES ROTATING UP THROUGH WRN AK BEFORE FEEDING BACK INTO THE BERING SEA MEAN TROUGH POSITION. TO THE EAST...A STRONGLY PUMPED AND WARMING MEAN RIDGE SPRAWLING FROM WRN CANADA UP ACROSS THE EAST-CENTRAL ALASKAN INTERIOR/NORTH SLOPE IS ONLY GRADUALLY ERODED OVER TIME. THIS PATTERN ALLOWS SEVERAL WELL ORGANIZED AND PCPN FOCUSING LOWS SPREAD PCPN ACROSS THE ALEUTIANS FROM SWRN TO THE WRN AK...FEEDING UP THE PERIPHERY OF THE RIDGE...BUT HEAVIEST PCPN SHOULD FOCUS MORE OVER SRN/SE AK IN DEEPER AND MOISTURE INFLOW. MODELS AND ENSEMBLES CONTINUE TO OFFER RESONABLY SIMILAR MID-LARGER SCALE PATTERN EVOLUTIONS THROUGH MEDIUM RANGE TIME SCALES. HOWEVER...SIGNIFICANT SMALL-MID SCALE DIFFERENCES REMAIN WITH EMBEDDED SYSTEM EMPHASIS AND TIMING INCLUDING MAIN LOW DEVELOPMENTS. ACCORDINGLY AGAIN PREFER AN ENSEMBLE MEAN BASED FORECAST SOLUTION TO MITIGATE THESE SYSTEM VARIANCES WHILE ALLOWING BETTER CONTINUITY. LIKE YESTERDAY...WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY DERIVED FROM A BLEND OF 70% 00 UTC ECMWF ENSEMBLE MEAN AND REASONABLY COMPATABLE 30% 06 UTC GFS ENSEMBLE MEAN. THE ECMWF ENSEMBLE MEAN WAS MORE LEANED ON AS IT SEEMED A TAD BETTER FIT THE SLOW TO TRANSITION LARGER SCALE PATTERN OVERALL WHILE PROVIDING BETTER WPC CONTINUITY. WPC MANUAL FORECASTER ADJUSTMENTS ADDED A BIT MORE SPECIFICITY AS APPROPRIATE. THIS AGAIN ALLOWED FOR SOME DEEPER LOWS CONSISTENT WITH SUPPORTING FAVORABLE DYNAMICS ALOFT. WPC PROGS SHOWS ONE SUCH LOW OVER THE NRN GULF OF AK FRI INTO SAT...THEN AGAIN INTO THE GULF OVER THE WEEKEND. MEANWHILE...ANOTHER DEEP LOW IS SHOWN UPSTREAM OVER THE ALEUTIANS AND INTO THE SRN BERING SEA OVER THE WEEKEND THAT USHERS IN FRESH ACTIVE WEATHER AND PCPN BY EARLY NEXT WEEK WITH A POTENTIAL TRACK AIMED THROUGH SWRN AK MON AND ONWARD INTO TUE WITH THE SPREAD OF HEAVIEST PCPN INTO SRN/SERN AK AND TO A LESSER EXTENT THE W-CENTRAL INTERIOR. SCHICHTEL