ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 204 PM EDT SAT JUL 30 2016 VALID 12Z WED AUG 03 2016 - 12Z SUN AUG 07 2016 ...GUIDANCE/UNCERTAINTY ASSESSMENT... THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE MAINTAINS CLOSE WPC CONTINUITY AS PRIMARILY DERIVED FROM A COMPOSITE BLEND OF REASONABLY WELL CLUSTERED GUDIANCE FROM THE 12 UTC GFS/00 UTC ECMWF AND THE GEFS/NAEFS/ECMWF ENSEMBLE MEANS DAYS 4-6 WED-FRI IN A PERIOD WITH SEEMINGLY AVERAGE OR BETTER PREDICTABILITY. SPREAD INCREASES RAPIDLY BY NEXT WEEKEND SO OPTED FOR JUST AN ENSEMBLE MEAN BLEND AMID GROWING UNCERTAINTY. ...PATTERN AND WEATHER HIGHLIGHTS/THREATS... THE CONTINUED STEADY PASSAGE OF AN AMPLIFIED MID-UPPER LEVEL LOW/TROUGH SPLIT OVER THE GULF OF AK WED AND THU WILL SUPPORT COMPACT SURFACE LOW/FRONTAL SYSTEM AND MOISTURE ENHANCEMENT. THIS WILL FUEL HEAVIER RAINS WRAPPED INTO SRN AND ESPECIALLY SERN AK THIS PERIOD AS ENHANCED BY FAVORED COASTAL TERRAIN. MEANWHILE...ENERGETIC NRN STREAM ARCTIC TROUGHING ALOFT SHOULD SUPPORT ORGANIZED BUT MODEST TRAILING SURFACE FRONTAL PRECIPITATION PASSAGE/COOLING INLAND DOWN ACROSS WRN/N-CENTRAL AK AND NRN BERING SEA MID-LATE NEXT WEEK. LATER...GUIDANCE STILL SHOWS SIGNALS FOR APPROACH INTO THE BERING SEA/ALEUTIANS THEN SW/WRN AK OF ERN ASIAN ENERGY THAT WOULD FAVOR LEAD SYSTEM EFFECTS/PCPN OVER THE REGION LATE WEEK/NEXT WEEKEND IN ADVANCE OF DEEPER SURFACE SYSTEM POTENTIAL MOVING IN UPSTREAM NEXT WEEKEND. SCHICHTEL