EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 107 AM EDT THU MAR 27 2014 VALID 12Z SUN MAR 30 2014 - 12Z THU APR 03 2014 ...SNOWSTORM TAKING SHAPE FOR THE NORTH CENTRAL STATES... APPARENTLY, THE NEW FLOW REGIME ACROSS THE CONTIGUOUS UNITED STATES AT THE MEDIUM RANGE IS STILL BEING SORTED OUT BY THE GLOBAL NUMERICAL GUIDANCE. WHAT APPEARED TO BE A SERIES OF PROGRESSIVE, OPEN WAVES AS RECENTLY AS 24 HOURS AGO IS NOW RESOLVING INTO A TRAIN OF SLOW-MOVING, CLOSED SYSTEMS TRACKING SOUTH OF A SPLIT IN THE WESTERLIES ACROSS SOUTHERN CANADA. USED THE ECENS MEAN FOR THE FRONTS AND PRESSURES, WITH A MODEST INCORPORATION OF THE NAEFS FOR TEMPERATURES AND POPS--CHOICES WHICH SEEM TO HAVE SERVED WELL AT THE MEDIUM RANGE OF LATE. THE SENSIBLE WEATHER UPSHOT OF THE TREND IN THE GUIDANCE IS TWO-FOLD. FIRST, WHOLESALE WARMING IS NOW CONTRAINDICATED ANYWHERE IN THE NATION DUE TO THE SUPPRESSED SOUTHERN STREAM OF THE POLAR JET. SECOND, THE PROPENSITY FOR THE WAVES TO CLOSE OFF WILL GREATLY INCREASE THE CHANCES OF SNOW ON THE NORTHWEST SIDE OF THE VORTICES, WITH THE COMMENSURATE SLOWER TRANSLATION PROLONGING THE WINTRY CONDITIONS--ULTIMATELY THE TOTAL ACCUMULATIONS. THE BIGGEST WINTER-WEATHER THREAT IN THE LOW ELEVATIONS WILL BE DAYS 4 AND 5 FROM NORTH DAKOTA TO THE UPPER PENINSULA OF MICHIGAN. WHILE THE ENTIRE WESTERN UNITED STATES IS VULNERABLE TO PRECIPITATION THIS PERIOD, THE NORTHERN HALF OF THE REGION SHOULD RECEIVE THE LION'S SHARE--WITH ALL THE MOUNTAIN RANGES RIGHT TO THE CONTINENTAL DIVIDE BUILDING THEIR SNOWPACK IMPRESSIVELY. CISCO