EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1154 AM EDT MON OCT 13 2014 VALID 12Z THU OCT 16 2014 - 12Z MON OCT 20 2014 ...OVERVIEW... MODELS AND ENSEMBLES NOW OFFER ABOUT AVERAGE FORECAST SPREAD WITH DEPICTION OF A TRANSIENT BUT OVERALL HIGHLY AMPLIFIED FLOW SCENARIO FOR NORTH AMERICA. THIS PATTERN AMPLITUDE MAY BE ASSOCIATED... AMONG OTHER FACTORS... WITH A DOWNSTREAM PROPAGATING EFFECT FROM EMBEDDING INTO THE MID/UPPER LATITUDE PACIFIC WESTERLIES SEVERAL RECENT AND VERY DEEP EXTRATROPICAL LOWS FORMALLY ASSOCIATED WITH TYPHOONS PHANFONE AND VONGFONG. WATER VAPOR LOOPS NOW STRONGLY SHOW AND SUPPORT AN AMPLIFIED NORTHERN HEMISPHERIC FLOW REGIME. ...GUIDANCE PREFERENCES AND UNCERTAINTY ASSESSMENT... WPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ARE PRIMARILY DERIVED FROM A BLEND OF THE 00 UTC GEFS MEAN AND ECMWF ENSEMBLE MEAN. THE NAEFS MEAN WAS ALSO PARTIALLY FAVORED FOR ITS TEMPERATURES/POP FORECASTS BUT WAS LESS DEFINED IN THE PRESSURE FIELD... AND NOT USED THERE. THIS ENSEMBLE MEAN FORECAST APPROACH WAS USED TO ADDRESS LINGERING AND LESS PREDICTABLE SMALLER SCALE SYSTEM VARIANCES... WITH AN EYE TOWARD CONTINUITY /WHICH WAS LARGELY MAINTAINED/. LARGEST UNCERTAINTY LIES WELL OFF THE EAST COAST WITH REGARD TO HOW QUICKLY TROPICAL STORM /AND POSSIBLY FUTURE HURRICANE PER NHC/ GONZALO GETS LIFTED NORTHWARD AHEAD OF A COLD FRONT THAT WILL CLEAR THE EAST COAST LATER THIS WEEK. INTERESTS IN BERMUDA SHOULD MONITOR THE NHC FOR THE LATEST FORECAST. ...SENSIBLE WEATHER HIGHLIGHTS... LATE THIS WEEK... THE FLOW PATTERN REMAINS DRIVEN BY A CLOSED/NEGATIVELY TILTED MID-UPPER LEVEL LOW/TROUGH SLATED TO LIFT SLOWLY NORTHEASTWARD FROM THE EAST-CENTRAL TO NORTHEASTERN US THURSDAY INTO SATURDAY. THIS WILL FOCUS PRECIPITATION OVER ESPECIALLY NEW ENGLAND... FUELED BY WELL-ESTABLISHED LEAD MOISTURE INFLOW. SECONDARY FRONT MOVING OUT OF THE PLAINS THU/D3 WILL BRING IN COOLER AIR WITH TEMPERATURES IN THE 50S/60S NORTH OF ABOUT 40N. IN THE WEST... TROUGH/RIDGE SETUP WAVERING/REFORMING ALONG 135W/110W... RESPECTIVELY... SHOULD FAVOR COPIOUS AMOUNTS OF PRECIPITATION JUST TO THE NORTHWEST OF WASHINGTON STATE OVER VANCOUVER ISLAND. APPROACHING SYSTEM ON FRIDAY SHOULD LOSE ITS BATTLE AGAINST HIGHER HEIGHTS AS IT DISSIPATES INLAND OVER INTERIOR WA/OR SATURDAY. BUILDING HEIGHTS THROUGH THIS COMING WEEKEND SHOULD LEAD TO A MARKED WARMUP FOR THE INTERIOR WEST /BETWEEN THE CASCADES AND THE WESTERN HIGH PLAINS/ WITH TEMPERATURES FORECAST TO CONSERVATIVELY RISE TO 10-20F ABOVE AVERAGE IN FAVORED DOWNSLOPE-ENHANCED AREAS. FRACASSO/SCHICHTEL