EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1056 AM EST MON JAN 26 2015 VALID 12Z THU JAN 29 2015 - 12Z MON FEB 02 2015 ...GENERAL FLOW PATTERN... MID-LEVEL ENERGY PHASING OVER THE MID-WEST LATE THIS WEEK WILL AMPLIFY OVER THE EAST BEFORE SWINGING OFF THE ATLANTIC COAST ON SATURDAY. UPSTREAM...A NORTHERN STREAM RIDGE BUILDING INTO THE NORTHWEST/BRITISH COLUMBIA WILL ALLOW SHORTWAVE IMPULSES TO DIVE SOUTHEASTWARD INTO THE NORTH CENTRAL U.S....EVENTUALLY CARVING OUT BROAD TROUGHING FROM THE NORTHERN/CENTRAL PLAINS TO THE NORTHEAST AND MID-ATLANTIC REGION BY EARLY NEXT WEEK. IN THE SOUTHERN STREAM...MID-LEVEL ENERGY EDGING IN OVER CALIFORNIA ON THURSDAY SHOULD GRADUALLY AMPLIFY WHILE SLOWLY SINKING SOUTHEASTWARD TOWARDS NORTHERN MEXICO THIS WEEKEND. ...MODEL DIFFERENCES AND PREFERENCES... DETAIL DIFFERENCES WITH THE PHASING OF ENERGY OVER THE MID-WEST ON THURSDAY LEAD TO SOME MODEL SPREAD WITH THE RESULTING SURFACE LOW WHILE IT TRACKS THROUGH THE OHIO VALLEY AND ESPECIALLY AS IT DEEPENS OFF THE NEW ENGLAND COAST FRIDAY INTO SATURDAY. IN GENERAL...THE DETERMINISTIC ECMWF HAS BEEN MORE PHASED/SLOWER/DEEPER WITH THE SURFACE LOW...WHILE THE GFS HAS BEEN FASTER/WEAKER WITH THE LOW. THE DAY 3-4 FORECAST RELIED HEAVILY ON THE 00Z ECMWF ENSEMBLE MEAN SINCE IT FIT WELL WITHIN THE MIDDLE OF MODEL SPREAD AND MATCHED WELL WITH WPC CONTINUITY. TOWARDS THE LATER HALF OF THE FORECAST PERIOD...THE GEFS MEAN AND ECMWF ENSEMBLE MEAN ARE IN DECENT AGREEMENT WITH THE MEAN FLOW OVER THE LOWER-48...HOWEVER...DETERMINISTIC GUIDANCE IS ADVERTISING A WIDE RANGE OF SOLUTIONS FOR SOME OF THE SMALLER SCALE FEATURES OVER THE CONUS. BY MONDAY MORNING...THE 00Z GFS DEVELOPS A DEEP SURFACE CYCLONE OVER THE UPPER MIDWEST WHILE THE 00Z ECMWF FAVORS THE IDEA OF DEVELOPING A LOW IN THE NORTHERN GULF AND TRACKING IT TOWARDS THE SOUTHEAST/SOUTHERN MID-ATLANTIC COAST. WITH SUCH A WIDE RANGE OF SOLUTIONS IN THE DETERMINISTIC GUIDANCE...THE WPC DAY 3-7 FORECAST RELIED ON ENSEMBLE MEAN GUIDANCE. ...SENSIBLE WEATHER HIGHLIGHTS... LIGHT TO MODERATE SNOW WILL BE POSSIBLE WITH THE SURFACE WAVE TRACKING THROUGH THE OHIO VALLEY THURSDAY. DEPENDING ON WHERE AND WHEN THE SYSTEM DEEPENS OFFSHORE...IT WILL HAVE THE POTENTIAL TO BRING STRONG WINDS AND SNOW TO COASTAL NEW ENGLAND...ON THE HEELS OF THE MAJOR NORTHEAST SNOWSTORM IN THE SHORT RANGE. BEHIND THIS FEATURE...THE BIG STORY WILL BE WITH THE ARCTIC AIR SURGING SOUTHWARD WITH THE BROAD TROUGH CARVING OUT OVER THE CENTRAL/EASTERN U.S.. GERHARDT