EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1155 AM EDT TUE OCT 07 2014 VALID 12Z FRI OCT 10 2014 - 12Z TUE OCT 14 2014 ...OVERVIEW AND GUIDANCE PREFERENCES... LIKE YESTERDAY...THE FORECASTS ARE RELATIVELY STRAIGHTFORWARD THROUGH THE WEEKEND/DAY 5 BUT DIFFERENCES AMPLIFY EARLY NEXT WEEK ON DAYS 6 AND 7. WHILE THE REMNANTS OF TROPICAL STORM SIMON WILL CONTRIBUTE TO ENHANCING MOISTURE FROM THE SOUTHWEST EASTWARD TOWARD THE PLAINS AND EASTWARD...THE LARGER SCALE PATTERN PRESENTS MORE CHALLENGES TO THE FORECAST. IT STILL REMAINS TO BE SEEN WHETHER AN AMPLIFIED VERSUS MORE PROGRESSIVE FLOW DOMINATES THE END OF THE FORECAST PERIOD. WHILE THE EMPHASIS HAS BEEN ON A TREND TOWARDS A MORE AMPLIFIED FLOW AS EXEMPLIFIED BY RECENT RUNS OF THE ECMWF AND ASSOCIATED MEANS...THERE STILL REMAINS A SIGNIFICANT FORECAST COMPONENT THAT REMAINS FASTER AND MORE PROGRESSIVE WITH SIGNIFICANT IMPLICATIONS TO THE FORECAST. FOR PURPOSES OF CONTINUITY...WE WILL CONTINUE TO USE A MORE AMPLIFIED APPROACH AS WAS USED YESTERDAY AND LAST NIGHT. THIS APPEARS TO HAVE RELATIVELY SMALL DIFFERENCES ON FRIDAY THROUGH SUNDAY. A MORE AMPLIFIED FLOW VERSUS A MORE PROGRESSIVE FLOW WILL HAVE SIGNIFICANT IMPLICATIONS REGARDING THE POTENTIAL FOR EXCESSIVE RAINFALL AS A DIGGING UPPER TROUGH COULD COMBINE WITH TS SIMONS REMNANTS FOR HEAVY RAINFALL FROM THE SOUTHWEST/SOUTH CENTRAL STATES INTO THE LOWER MISSISSIPPI VALLEY TO A FASTER/DRIER SOLUTION WITH FRONTS SLIDING EASTWARD WITHOUT THE POTENTIAL FOR HEAVY RAINFALL. FOR THE TIME BEING...WE ARE STILL GOING WITH A SOLUTION THAT FAVORS SOME POTENTIAL FOR HEAVY RAINFALL. THE OVERNIGHT GEFS/NAEFS SOLUTION STILL FAVORS A FASTER EVOLUTION WITH THE NAEFS RUNS OBVIOUSLY FAVORING THE GFS VERSUS CANADIAN SOLUTIONS. FOR WHAT ITS WORTH...THE CANADIAN MEANS START OFF SLOWER AND DEEPER THAN THE GEFS/NAEFS BUT THEN VEERS TO A HIGHLY DIFFERENT SOLUTION FAVORING A DEEPENING TROUGH OVER THE WEST COAST BY DAY 7. THE ECMWF ENSEMBLE MEAN SOLUTION CONTINUES TO FAVOR A DEEPER SLOWER SOLUTION. WITHOUT HAVING TO FAVOR THE MORE AMPLIFIED ECMWF VS THE OTHER SOLUTIONS...HAVE ELECTED TO ATTEMPT A SOLUTION THAT SHOWS A DUAL LOW SYSTEM...AS DONE LAST NIGHT...LATE IN THE FORECAST THAT MAINTAINS THE UNCERTAINTY IN THE MANUAL FORECAST SHOWN ON DAYS 6 AND 7. THAT TRANSLATES INTO A FASTER/WEAKER CYCLONE OVER THE LOWER MS VALLEY ON DAY 7...AND A STRONGER/SLOWER CYCLONE OVER THE UPPER MIDWEST. IN OTHER WORDS...LOW CONFIDENCE BUT SOMETIMES THATS THE WAY IT IS AT THIS TIME SCALE. ...SENSIBLE WEATHER HIGHLIGHTS... PRECIPITATION WILL LIKELY FOCUS ALONG THE FRONTAL BOUNDARY THAT EXTENDS FROM THE SOUTHERN PLAINS TO THE MID ATLANTIC COAST BEFORE IT STARTS LIFTING NORTHWARD TOWARD THE END OF THE END OF THE WEEKEND. AS THE COLD FRONT PUSHES THROUGH THE NORTHWEST DURING THE SAME TIME PERIOD...THERE SHOULD BE FAIRLY WIDESPREAD BUT LIGHT TO MODERATE QPF WITH SOME MOUNTAIN SNOW... ENHANCED WITH THE TERRAIN. THERE REMAINS A HEAVY RAINFALL POTENTIAL FOR NEXT MONDAY/TUESDAY/DAYS 6-7 IN THE MID- AND LOWER-MS VALLEY SHOULD THE SHARP/DEEP TROUGH FORM AS FORECAST. TEMPERATURES SHOULD WARM IN THE EAST WITH RIDGING BUILDING DOWNSTREAM OF THE TROUGH. COOLING TEMPERATURES SHOULD ACCOMPANY THE FRONT IN THE WEST BUT WILL BE TEMPERED DUE TO THE MARITIME AIRMASS ORIGINS. KOCIN