EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1059 AM EST MON JAN 06 2014 VALID 12Z THU JAN 09 2014 - 12Z MON JAN 13 2014 ...OVERVIEW AND MODEL PREFERENCES... UPPER PATTERN OVER NORTH AMERICA WILL TRANSITION SHARPLY FROM A RATHER ZONAL FLOW TO END THE WEEK INTO A RIDGE/TROUGH/RIDGE PATTERN BY MON/D7. THE PACIFIC WILL BECOME MUCH MORE ACTIVE WITH A STRONG JET OFF OF EASTERN ASIA INTO A SPLIT FLOW EAST OF THE DATELINE. THIS WILL SEND SEVERAL BOUTS OF ENERGY THROUGH THE GULF OF ALASKA INTO THE PAC NW AND BRITISH COLUMBIA. SUCCESSIVE SHORTWAVES DIVING THROUGH THE WEST SHOULD FAVOR THE LONGWAVE TROUGH AXIS BETWEEN 100-110W... ALLOWING THE WESTERN ATLANTIC RIDGING TO NOSE BACK INTO THE BAHAMAS AND FLORIDA IN A POWER STRUGGLE THAT HAS BEEN PLAYED OUT FOR THE LAST SEVERAL WEEKS. THE MODELS AND ENSEMBLES HAVE GENERALLY SHOWED THIS EVOLUTION BUT DETERMINISTIC CONTINUITY WITHIN EACH MODEL HAS BEEN POOR. THE PROGRESSIVE NATURE OF EACH SYSTEM /ASIDE FROM THE POSSIBLE BRIEFLY CLOSED SYSTEM OVER NORTHERN MEXICO ON SAT/D5/ INCREASES THE SPREAD AMONG DETERMINISTIC RUNS... SO HAVE CONTINUED TO RELY ON THE GEFS/ECENS MEANS WHICH SHOW MUCH BETTER AGREEMENT THROUGH ABOUT SUN/D6 AT THE EXPENSE OF MORE DETAIL IN THE FORECAST. BY MON/D7... HAVE FAVORED THE ECENS OVER THE GEFS SINCE THE FORMER KEPT THE TROUGH AXIS ALONG AND WEST OF 100W WHILE THE LATTER WAS MORE PROGRESSIVE... GIVEN THE RESILIENCY OF THE WESTERN ATLANTIC RIDGE OVER THE PAST SEVERAL WEEKS /EVEN TO 90 DAYS/. ...SENSIBLE WEATHER HIGHLIGHTS... PRECIPITATION SHOULD FOCUS OVER THE PAC NW WITH THE PERSISTENT ONSHORE FLOW... AS WELL AS OVER THE LOWER MS VALLEY INTO THE TN/OH VALLEY IN THE CONFLUENT FLOW ALOFT. PATTERN DOES NOT SUPPORT RAPID DEEPENING OF ANY SYSTEM BUT THE PAC NW WILL ADD UP THE RAIN/SNOW FAIRLY EFFICIENTLY OVER THE NEXT WEEK. SEVERAL INCHES OF RAIN /AND SEVERAL FEET OF SNOW IN THE CASCADES/ ARE LIKELY. TEMPERATURES WILL WARM NICELY IN THE EAST AS HEIGHTS RISE BUT WITH A PAUSE IN THE ARCTIC AIR INVASION MOST OF THE CONUS SHOULD BE NEAR TO ABOVE NORMAL DURING THE PERIOD. FRACASSO