Meteorological March Madness

Fourteen years ago tonight, I was highly confident that a blockbuster storm was going to paralyze the area. In fact, I went out on a limb and predicted that pummeling on the WBZ evening newscasts the day before. That day was Easter Sunday and it had been beautifully sunny with highs of 60-65 degrees! Boston ended up with 25.4 inches of snow in about 12 hours ending on the morning of April Fool's Day! How appropriate is that? Fourteen years later, there are some similarities and significant differences. It was sunny and 55 degrees yesterday and right now it is snowing. However, despite my guarantee that over two feet of snow will not fall in Boston, my confidence in this event is much lower for parts of the region. Springtime storms contain their own set of rules and figuring out the thermal profile of the atmosphere is paramount in determining the precipitation type. Air temperature changes as small as fractions of a degree can make the difference between cold rain drops and wet snow flakes. I simply dub it meteorological March Madness on these last few hours of the month.

The rain which developed this afternoon was anticipated according to yesterday's forecast although it was delayed by a few hours. I also expected a transition into snow but I did not foresee the level of intensity that is happening early this evening. Consequently, a revision is necessary from Rhode Island into Bristol and Plymouth County where moderate to almost heavy snow will be accumulating on the trees, grassy surfaces and vehicles. There could be a few inches at least in places in this region before a switch back to rain occurs. Many roads will be just wet but some slushy and slippery areas cannot be ruled out. Over most of Cape Cod, it will be all rain except some flakes mixed in at times near the canal to about mid-evening. This ribbon of precipitation is expanding northeastward into the rest of the region so snow will become widespread. As the evening progresses, advection of milder air aloft should produce a transition back to to rain from the Canal and the South Coast northwestward toward Boston. That rain line should be in the I-95 corridor by midnight-1am. Most indicators signal this rain line will advance to a Worcester to Lawrence line by 3-4am. Based upon this projection, most of the area near and southeast of the I-95 corridor will have at least a couple inches mainly on the grassy surfaces and trees with scattered slushy locations possible. Farther north and west in the I-495 area north of the Mass Pike, 2 up to 6 inches of wet snow could accumulate on the grassy surfaces and trees with less on the roads and just slushy areas on the main roads. From northern Worcester County west and north plus perhaps the northwestern tip of Middlesex County into northern New England, more than 6" of snow is likely with amounts to 12" especially in elevated, hillier terrain. This challenging weather system will become organized and energized as the main center exits the North Carolina coastline later this evening on its path to outer Cape Cod tomorrow morning. Its shield of heavier precipitation will exit southern New England during or just after the morning commute. It will be a high impact storm in Maine and eastern NH with some snow totals well over a foot away from the immediate coastline with howling winds approaching 40-60 mph. I expect 20-40 mph winds over much of southern New England later tonight and tomorrow.  With a scheduled tide height of about 9.5 feet and a potential surge of 1.5 to 2 feet, there is only a risk of some splashover onto the usual most vulnerable shore roads closer to and just after the high tide time near 11am. Scattered power outages are possible but mainly in the area where the heaviest wet snow falls over northern Worcester County northward. In the wake of the storm, there will be plenty of wind through the weekend with a mix of clouds and sunshine Saturday with highs in the upper 40s to near 50. A sunnier day is expected on Sunday with highs in the lower 50s. Some rain may return on Monday as a warm front approaches from the southwest.

For the skiers and boarders, I was at Bretton Woods on Tuesday so I can tell you that the alpine and nordic trails and slopes conditions are already fabulous and they will become extra outstanding as most all of the resorts receive at least 6-12 inches of fresh snow. Favorable upslope areas in the northern mountains will have well over a foot as the snow lingers in bursts through tomorrow night. It is a higher density snow and not the real fluff that we would all like but with grooming, it will be dynamite. There could be a few spotty flurries in the mountains on Saturday with more sunshine on Sunday. Both days will be windy with highs in the 30s up there. It's not too late to plan a late season ski trip for this weekend. You'll be glad you did. Please take a few alpine or nordic runs for me and have a safe and happy time this weekend on the alpine and nordic.

I will be digesting more data and studying the progression of this weather event through the evening. If any revisions are warranted, I will post a fresh blog later this evening otherwise Melissa Mack and Joe Joyce will be here early in the morning.

Have a good night.