EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1056 AM EST THU DEC 24 2015 VALID 12Z SUN DEC 27 2015 - 12Z THU DEC 31 2015 ...STRONG WINDS...HEAVY RAIN...AND ACCUMULATING SNOW EXPECTED WITH A DEEP CYCLONE LIFTING OUT OF THE SOUTHERN PLAINS EARLY NEXT WEEK... ...GENERAL FLOW PATTERN... THE FLOW OVER THE LOWER 48 WILL INITIALLY BE DOMINATED BY A DEEP CLOSED VORTEX EJECTING OUT OF NORTHERN MEXICO ON SUNDAY AND THE ASSOCIATED SURFACE CYCLONE TRACKING FROM TEXAS TO THE MIDDLE MISSISSIPPI VALLEY EARLY NEXT WEEK. AS THE VORTEX WEAKENS AND LIFTS TOWARDS THE UPPER GREAT LAKES...UPSTREAM SHORTWAVE ENERGY PROGRESSING INLAND FROM THE NORTHEAST PACIFIC SHOULD CARVE OUT ANOTHER WESTERN U.S. TROUGH BY THE MIDDLE OF NEXT WEEK. GERHARDT