Temperatures over the past few days have been averaging out well above normal. In Washington, Reagan National Airport eclipsed 80 on Monday for the first time this year, but all of this is rapidly coming to an end. Across the United States, the months of March and April signify the coming of volatile and rapidly changing weather patterns--from severe weather outbreaks, to late-season snowstorms, to flooding rains, all of which have been present for the past few days.

A massive storm system, which originated from a Pacific Upper Level wave of energy about 12 days ago, is responsible for the major severe weather outbreak that ravaged the Midwest and Southeast yesterday, blizzard and severe winter storm conditions to the North, and flooding rains to the south. This same storm system ran a cold front through the region today, and will drop temperatures into the mid 40s for highs by the end of the week (see image at right)

Low temperatures are expected to dip below freezing tomorrow night, which is why the National Weather Service has issued a Freeze Watch for areas east of the Blue Ridge Mountains. Any trees or flowers that have already begun to bloom due to the unseasonably warm air as of late have the potential to be damaged or killed in the cold weather.

Image above: 15 hour forecast image from this afternoon's run of the WRF-NAM numerical weather model valid Thursday mid-morning. Notice the surface temperatures hovering just around freezing in the Mid Atlantic.

Image courtesy of the PSU E-Wall

Late Season winter-storm battering the Northeast:
The same storm system responsible for the severe weather in the Midwest and the significant cold blast in the Mid Atlantic is also bringing a heavy, wet snowfall to portions of New England and the Upper Midwest. Driving through Williamstown, Massachusetts was a chore today (looking at colleges), as freezing rain and sleet covered roadways at higher elevations. A changeover to snow will occur later tonight, and snowfall totals of 3-6 inches are in the forecast over the next 24 hours.

Further to the north and east, snowfall totals are expected to range from 6 to 18 inches across Vermont, New Hampshire, and Maine.