EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1237 AM EST SUN MAR 12 2017 VALID 12Z WED MAR 15 2017 - 12Z SUN MAR 19 2017 ...RECORD HIGHS LIKELY IN PARTS OF THE WEST BUT RECORD COLD POSSIBLE IN THE EAST... ...OVERVIEW... FORECAST FOR WEDNESDAY INTO NEXT WEEKEND IS FOR THE RIDGE IN THE WEST AND TROUGH IN THE EAST TO RELOAD, SETTING UP A SEVERAL DAYS OF WARM/HOT TEMPERATURES IN THE SW STATES AND VERY COLD TEMPERATURES FOR MUCH OF THE EAST. SHORT TERM NOR'EASTER WILL EXIT SLOWLY BUT STEADILY AWAY FROM NEW ENGLAND ON WEDNESDAY AS THE NEXT SYSTEM PUSHES THROUGH WA/OR AND THE NORTHERN ROCKIES. THAT WILL MOVE EASTWARD INTO THE GREAT LAKES AROUND FRIDAY AND PAST THE APPALACHIANS SATURDAY. ...GUIDANCE PREFERENCES AND EVALUATION... MODEL/ENSEMBLE CONSENSUS (18Z GFS/GEFS AND 12Z ECMWF/ECENS MEAN) OFFERED A REASONABLE STARTING POINT FOR THE PERIOD. ECMWF WAS FAIRLY SLOW TO RAISE HEIGHTS IN THE NORTHEAST COMPARED TO MOST OF THE GUIDANCE, DEPENDING ON HOW AN UPSTREAM SHORTWAVE TRAVERSES THROUGH CANADA). FOR NOW, THE BLEND SUFFICED. GFS CONTINUES TO HAVE SOME TROUBLE WITH THE DETAILS/EVOLUTION OF THE WESTERN FRONT AND NORTHERN/SOUTHERN AREAS OF LOW PRESSURE IN THE CENTRAL PLAINS BY LATE THURSDAY INTO FRIDAY. ECMWF HAS BEEN MORE CONSISTENT BUT EITHER FALL WITHIN THE ENSEMBLE SPREAD. THAT SHOULD TRACK EASTWARD IN SOME MANNER (PERHAPS DEVELOPING A SOUTHERN WAVE ALONG THE FRONT, BUT PAST GFS RUNS HAVE FAVORED THE NORTHERN LOW MORE) AS ANOTHER SYSTEM ENTERS THE PAC NW. RIDGE SHOULD FINALLY BE SHUNTED A BIT EASTWARD BY THE END OF THE PERIOD PER THE ENSEMBLES, THOUGH THE TREND HAS BEEN SLOWER OVER THE PAST FEW RUNS. ...WEATHER HIGHLIGHTS... EXPECT A PROLONGED PERIOD OF VERY WARM (EVEN HOT) TEMPERATURES OVER THE WEST AND AT TIMES EXTENDING INTO THE PLAINS. EACH DAY HAS THE POSSIBILITY TO TIE OR SET DAILY RECORD HIGHS AND/OR WARM LOWS SOMEWHERE IN THE FOUR CORNERS STATES AND INTO NEVADA/WYOMING. IN STARK CONTRAST TO THE WEST, VERY COLD TEMPERATURES ARE FORECAST IN THE EAST FOR MID-MARCH (10-20F BELOW NORMAL READINGS WITH SOME AREAS 20-30F BELOW NORMAL ONE OR MORE DAYS EARLY IN THE PERIOD). RECORD LOWS ARE POSSIBLE BOTH FOR MIN AND MAX TEMPERATURES. TEMPS SHOULD MODERATE BY NEXT WEEKEND BUT ONLY BACK TO NEAR NORMAL. THE PAC NW WILL SEE PERIODS OF VALLEY RAIN AND HIGHER ELEVATION SNOW THAT SHOULD EXTEND EASTWARD INTO THE BITTERROOTS AND SAWTOOTH RANGE AND TO YELLOWSTONE AS THE LEAD FRONT MOVES EASTWARD. SNOW LEVELS SHOULD REMAIN RATHER HIGH GIVEN THE WARM PACIFIC AIR MASS. COVERAGE/INTENSITY/TYPE OF DOWNSTREAM PRECIPITATION FROM THE PLAINS INTO THE EAST LATE WEEK INTO THE WEEKEND IS LESS CERTAIN, WITH SNOW NORTH AND RAIN SOUTH. TELECONNECTIONS RELATIVE TO THE MEAN PATTERN AS WELL AS NRN STREAM DOMINANCE OF THE DYNAMIC SUPPORT AND A FAIRLY WEAK SIGNAL FOR ANY SIGNIFICANT LOW LEVEL GULF INFLOW SEEM TO FAVOR LEANING AWAY FROM THE HEAVIER SIDE OF THE QPF SPREAD AT LEAST ACROSS THE SOUTH. NEXT SYSTEM TO AFFECT THE NORTHWEST SHOULD BRING IN ANOTHER PERIOD OF MODEST PRECIPITATION AROUND FRI-SUN. FRACASSO