EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1103 PM EST THU NOV 24 2016 VALID 12Z MON NOV 28 2016 - 12Z FRI DEC 02 2016 ...HEAVY RAINS EXPECTED FROM THE MISSISSIPPI VALLEY INTO THE EAST, PARTIALLY RELIEVING DROUGHT CONDITIONS... GENERAL FLOW PATTERN/MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SIGNIFICANT POSITIVE MID-LEVEL ANOMALIES ACROSS EASTERN CANADA AND THE NORTHEAST PACIFIC FAVOR A POSITIVELY TILTED TROUGH FROM THE CENTRAL US/CANADIAN BORDER INTO THE WESTERN UNITED STATES. THE GUIDANCE DOES NOT DISAPPOINT, GENERAL FAVORING THIS PATTERN. FOR MONDAY AND TUESDAY, A COMPROMISE OF THE 12Z UKMET/12Z ECMWF/12Z CANADIAN/18Z GFS SHOULD DEAL WITH ANY DETAIL ISSUES FOR PRESSURES/WINDS/500 HPA HEIGHTS. THEREAFTER, THE 12Z CANADIAN BECOMES OUT OF PHASE WITH THE REMAINDER OF THE DETERMINISTIC AND ENSEMBLE MEAN GUIDANCE NEAR THE PACIFIC NORTHWEST LATE TUESDAY AND NORTHEAST ON THURSDAY, SO DROPPED IT FROM CONSIDERATION, TRANSITIONING TOWARDS AN 18Z GFS/12Z ECMWF/12Z ECMWF ENSEMBLE MEAN/12Z NAEFS MEAN COMPROMISE BY THURSDAY AND NEXT FRIDAY. THE TEMPERATURES, RAIN CHANCES, CLOUD COVER, DEW POINTS, AND WEATHER WERE MORE ENSEMBLE MEAN BASED, AS USUAL. THE PRECIPITATION FORECAST FOR DAYS 4-7 IS EXPECTED TO BE MAINLY BASED ON THE 12Z ECMWF AND 18Z GFS. THIS OVERALL IDEA SHOULD MAINTAIN REASONABLE CONTINUITY WITH DAY SHIFT. WEATHER HIGHLIGHTS/THREATS ~~~~~~~~~~~~~~~~~~~~~~~~~~ THE WEST WILL SEE PERIODS OF RAIN/HIGHER ELEV SNOW IN ASSOCIATION WITH BUNDLES OF MID LEVEL ENERGY. CA AND THE SOUTHWEST MAY SEE A PERIOD OF PRECIPITATION IN THE FIRST HALF OF THE PERIOD FOLLOWED BY A DRYING TREND AS TRAILING MOISTURE SHOULD BE LIMITED TO AREAS FROM THE NORTHWEST INTO THE NRN-CNTRL ROCKIES. SANTA ANA/FOEHN CONDITIONS WITH GUSTY WINDS ARE POSSIBLE DOWNWIND OF THE TRANSVERSE RANGES OF SOUTHERN CA MONDAY NIGHT AND MID NEXT WEEK DUE TO THE POSSIBILITY OF "INSIDE SLIDER" SHORTWAVES ALOFT MOVING BY THE SIERRA NEVADA. OVER THE CENTRAL AND EASTERN STATES, CONFIDENCE REMAINS FAIRLY HIGH IN ONE OR MORE EPISODES OF HEAVY RAIN WITHIN AN AREA NEAR THE LOWER MS VALLEY INTO THE CENTRAL APPALACHIANS GIVEN A PERIOD OF ENHANCED GULF INFLOW AND ENERGY ALOFT, WITH A POTENTIALLY STRONG UPPER LEVEL JET STREAM WITH 160+ KT WINDS. CONSULT SPC OUTLOOKS FOR LATEST INFO REGARDING STRONG TO SEVERE CONVECTION POTENTIAL, CURRENTLY INDICATED OVER SOUTHEAST TX INTO LA ON WEDNESDAY. SOME COLD SECTOR SNOWFALL IS POSSIBLE OVER THE NORTHERN TIER THOUGH COVERAGE BEHIND THE INITIAL NORTHERN PLAINS LOW MAY BE FAIRLY NARROW. DEPENDING ON STRENGTH OF SFC DEVELOPMENT, THERE MAY BE ONE OR MORE PERIODS OF STRONG WINDS OVER THE EASTERN 2/3 OF THE LOWER 48. CONTINUE TO EXPECT HIGHEST ANOMALIES FOR TEMPS TO BE AHEAD OF THE ADVANCING PLAINS SYSTEM AND TRAILING FRONT WITH A DECENT AREA SEEING HIGH AND LOW TEMPERATURE READINGS 10-20F ABOVE NORMAL, PERHAPS LOCALLY HIGHER. THERE MAY BE A FEW LOCATIONS WITH RECORD WARM MINIMA. COLD ANOMALIES BEHIND THE SYSTEM SHOULD BE MORE MODEST WITH ONLY A FEW POCKETS MORE THAN 10F BELOW NORMAL OVER THE WEST/ROCKIES. ROTH/RAUSCH