EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1150 AM EDT WED SEP 24 2014 VALID 12Z SAT SEP 27 2014 - 12Z WED OCT 01 2014 ...HEAVY RAIN POSSIBLE FOR THE NORTH CENTRAL AND NORTHEASTERN GULF COAST NEXT WEEK... ...OVERVIEW... IN A CHANGE FROM MOST OF THE PAST YEAR... A BROAD UPPER-LEVEL RIDGE WILL PREVAIL ACROSS THE EAST WHILE AN ENERGETIC UPPER-LEVEL TROUGH DOMINATES THE WEST. A PESKY STATIONARY FRONT SHOULD LINGER ALONG THE GULF/SOUTHEAST COASTS THROUGH THE PERIOD... SUPPORTING BOUTS OF RAINFALL... POSSIBLY HEAVY. TEMPERATURES SHOULD AVERAGE NEAR AVERAGE IN THE SOUTHEAST... ABOVE AVERAGE IN THE PLAINS EASTWARD INTO THE NORTHEAST... AND BELOW AVERAGE IN THE WEST. ...MODEL/GUIDANCE PREFERENCES AND UNCERTAINTY ASSESSMENT... THE 00Z MODELS/ENSEMBLE MEANS GENERALLY CLUSTER WELL TOGETHER THROUGH NEXT WED/D7... WITH THE EXCEPTIONS BEING THE GFS AND UKMET. THE 00Z-06Z GFS RUNS AMPLIFY ENERGY IN ONTARIO EARLY NEXT WEEK UNLIKE ALL BUT TWO OF THE 90-MEMBER ENSEMBLE RUNS AND PUSH THIS EAST SOUTHEASTWARD INTO THE NORTHEAST TUE/D6 INTO WED/D7 WHILE THE OVERWHELMING CONSENSUS SHOWS THE RIDGE AXIS MOVING EASTWARD PAST 80W. IN THE WEST... THE 00Z-06Z GFS RUNS APPEAR TO BE MUCH TOO AGGRESSIVE WITH ENERGY MOVING NORTHEASTWARD ONTO THE HIGH PLAINS TUE/D6 WHEREAS THE OTHER MODELS/ENSEMBLES SHOW THIS ENERGY STREAMING NORTHWARD INTO CANADA. USED A BLEND OF THE 00Z ECMWF AND ECENS/GEFS/NAEFS MEANS THROUGH THE PERIOD WITH ONLY A BLEND AMONG THE MEANS FOR WED/D7 WHEN THE DETAILS OF THE ECMWF IN THE EAST WHEN IT PERHAPS BECOMES TOO SLOW TO WEAKEN A MID-LEVEL SHORTWAVE STUCK IN THE LOWER MS/OH VALLEY... BUT IS NOT OUT OF THE REALM OF POSSIBILITIES. ...SENSIBLE WEATHER HIGHLIGHTS... DAMP... COLD... AND CLOUDY ALONG THE NORTHERN DIVIDE WITH THE UPPER-LEVEL TROUGH AND MILD IF NOT A BIT WARM BENEATH THE UPPER-LEVEL RIDGE BULGING NORTHEASTWARD ACROSS THE UPPER GREAT LAKES AND NORTHERN NEW ENGLAND. TEMPERATURES SHOULD AVERAGE A GOOD 10-15F BELOW CLIMO IN THE INTERIOR PAC NW THROUGH THE PERIOD WITH A NEARLY BALANCING 10F ABOVE CLIMO IN THE NORTHERN TIER/GREAT LAKES. PRECIPITATION SHOULD BE WIDESPREAD THROUGH MUCH OF THE WEST OUTSIDE COASTAL AND SOUTHERN CALIFORNIA. REINFORCING TROUGHING NEXT WEEK COULD LOWER TEMPERATURES ENOUGH FOR MORE THAN JUST HIGHEST ELEVATION SNOWFALL. THE MODELS AND ENSEMBLES SHOW A STRONG SIGNAL FOR AT LEAST MODEST TO PERHAPS HEAVY RAINFALL FOR THE GULF COAST FROM ABOUT NEW ORLEANS EASTWARD TOWARD THE BIG BEND OF FLORIDA INVOF APALACHEE BAY. THE 00Z ECMWF ENSEMBLE MEAN SHOWS PROBABILITIES OF AT LEAST THREE INCHES OF RAIN DURING THE MEDIUM RANGE PERIOD OF 30 TO 70 PERCENT IN THIS REGION... WHICH IS QUITE HIGH FOR THIS LEAD TIME OUTSIDE OF A TROPICAL OR NORTHERN PACIFIC SYSTEM. FRACASSO/VOJTESAK