EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1059 AM EST SAT FEB 22 2014 VALID 12Z TUE FEB 25 2014 - 12Z SAT MAR 01 2014 ...OVERVIEW... A VERY FAMILIAR UPPER PATTERN IS FORECAST FOR THE MEDIUM RANGE PERIOD TO CLOSE OUT FEBRUARY AND START MARCH... WITH A STRONG POSITIVE ANOMALY AT 500MB OVER NORTHERN ALASKA AND A DOWNSTREAM NEGATIVE ANOMALY NEAR THE GREAT LAKES. THIS ENSURES ANOTHER COLD PERIOD IN THE EAST WITH POTENTIAL SFC LOW DEVELOPMENT ALONG THE COAST. WITH A FORECAST CLOSED HIGH OVER ALASKA... THIS WILL ALLOW ENERGY TO SLIDE EASTWARD THROUGH THE WESTERN STATES... EVEN INTO SOUTHERN CALIFORNIA... AND EVENTUALLY INTO THE SOUTHEAST. ...MODEL PREFERENCES AND UNCERTAINTY ASSESSMENT... THE 00Z ECMWF AND 00Z ECENS/GEFS MEANS PROVIDE GOOD CLUSTERING WITH THE FORECAST THROUGH ABOUT THU-FRI/D5-6. THE RECENT GFS RUNS DEPART FROM THE MEANS AND ONGOING WPC CONTINUITY BY WED/D4 AS LOW PRESSURE DEVELOPS OVER NC AND HEADS NORTHEASTWARD. UKMET/CANADIAN BASICALLY LIE IN BETWEEN THE FARTHER EAST GFS RUNS AND THE FARTHER WEST ECMWF. WILL CONTINUE THE PREFERENCE TOWARD A FARTHER WEST SYSTEM GIVEN THE WESTWARD TREND IN MANY SYSTEMS OVER THE PAST SEVERAL WEEKS IN THE DAY 4-5 TIME RANGE. BY THU/D5... NEGATIVE-TILT TROUGH IN THE EASTERN PACIFIC EDGES INLAND ACROSS THE WEST COAST AND GREAT BASIN THU/D5 AND BEGINS WORKING EASTWARD ACROSS THE CENTRAL DIVIDE. THIS SHOULD MAINTAIN A SURFACE FRONT INTO THE GREAT BASIN/SOUTHERN CALIFORNIA THEN INTO THE SOUTHERN PLAINS BY FRI/D6 AS COLD ARCTIC AIR PUSHES THROUGH THE NORTHERN PLAINS OUT OF CANADA. BY SAT/D7... SOUTHERN STREAM ENERGY SHOULD RIDE ALONG THE GULF COAST AND POTENTIALLY FOCUS LOW PRESSURE NEAR NORTHERN FLORIDA PER THE ECMWF/CANADIAN AND ECENS MEAN. THE GFS/GEFS MEAN WERE FARTHER OFFSHORE AND WEAKER... WHICH IS WHERE THE ECMWF/ECENS MEANS HAVE TRENDED FROM IN THE PAST FEW DAYS. FINALLY... YET ANOTHER SYSTEM SHOULD PUSH THROUGH CA/OR INTO THE GREAT BASIN... WITH BETTER GEFS/ECENS MEAN AGREEMENT. ...SENSIBLE WEATHER HIGHLIGHTS... BACK TO THE BITTER WINTER COLD ACROSS THE NORTHERN PLAINS... GREAT LAKES... AND NORTHEAST FOR MUCH OF THIS MEDIUM RANGE PERIOD. FORECAST TEMPERATURES MAY BE A GOOD 25+ BELOW NORMAL WITH PLENTY OF SINGLE-DIGIT HIGH TEMPERATURES FOR PORTIONS OF ND/MN/WI/MI. LOW TEMPERATURES WILL LIKELY DROP BELOW ZERO ALONG MUCH OF THE I-80 CORRIDOR FROM EASTERN NEBRASKA TO THE POCONOS. THIS MAY FLIRT WITH RECORD LOW MINS/MAXES IN SOME LOCATIONS. IN THE SOUTHERN STATES... HIGHS MAY STRUGGLE TO REACH THE 40S WITH LOWS NEAR TO BELOW FREEZING LATER NEXT WEEK EVEN TO THE GULF COAST OF THE FL PANHANDLE. OUT WEST... RAIN RETURNS TO CENTRAL AND SOUTHERN CALIFORNIA WITH THE FLOW AHEAD OF THE SLOW-MOVING NEGATIVE-TILT TROUGH OUT OF THE SOUTH AND SOUTHEAST. LESSER RAINFALL CHANCES OVER OREGON AND WASHINGTON IN THIS PATTERN AND BY FRI-SAT/D6-7 COOLER WEATHER WITH HIGH-ELEVATION SNOWS FOR THE DESERT SOUTHWEST... GREAT BASIN... AND WESTERN CONTINENTAL DIVIDE. IN THE DEEP SOUTHWEST... E.G. PHOENIX AREA... SO FAR IN 2014 THEY HAVE YET TO MEASURE ANY RAINFALL. THE RAINLESS STREAK THERE MAY COME TO AN END BY THE END OF THE PERIOD. FRACASSO/VOJTESAK