Snow continues moderate to heavy especially along the immediate coastline and south shore of the area. I updated the snowfall map for metro Boston slightly. The largest totals will be south of Plymouth. There the heavy snow will create a situation where driving will become virtually impossible through about midnight. The heavy snow and wind will also impact the immediate shore line. Route 1 from Boston to Salem and through the North Shore will also continue very difficult this evening. The further west you are, the less difficult travel will be. For the most populated parts of eastern Massachusetts this is a small event while for parts of southeastern areas and Cape Cod, it's quite a different story.
Explosive cyclogeneis or bombogenesis are meteorological terms used to describe the rapid intensification of a low pressure system or storm. Atmospherically, the air is rushing off the planet so fast in the center of the storm it creates an air hole of sorts in the middle. Air then rushes in to replace the rapidly rising air and results in a lot of wind. It’s sort of like digging a hole at the beach and watching the water fill it up really fast. This is the weather situation we have developing right now. In these situations a tiny shift in the storms track and your position relative to the storm can have major implications to snow totals.
Picture yourself trying whack someone with your hand, I’ll let you choose who it is. If at the same time you extend your arm to impact them, you started moving away you might miss them. If you move quickly, you give them a glancing blow and if you slow down they feel the full impact of your hand. The big ocean storm is going to brush areas just west of Worcester while hitting areas over Cape Cod full force. Ok, enough analogies, I know get the accumulation.
Blizzard defined again
A blizzard is a three hour periods when winds blow at over 35 miles oer hour and the visibility (how far you can see ahead)is reduced to under one-quarter mile, due to either falling snow or snow blowing around off the ground. The weather service expects these conditions to be met along the coast so a blizzard warning has been issued.
When it begins
The storm hits this afternoon roughly between 2 and 4PM and then ramps up to full force between 6PM and midnight. During this time, the snow could come down at 1 to 3 inches per hour. While all this is happening, the back edge of the snow will already be pushing eastward.
I'll be updating the forecast throughout the weekend here and on Twitter @growingwisdom.
The further east you live, the longer it will snow and therefore the higher the amounts. There will likely be very sharp gradients of snow totals again from Rockport to Reading and Boston to Boxford.
The snow is going to get blow around a lot. Winds will be strong with the storm and there could again be scattered power outages from this quick hitting nor’easter. Much of Cape Cod has started as snow and without any rain I have increased totals similar to those on the other side of the canal through Plymouth.
What could change
From this point forward I will be watching the radar to see where the heaviest bands set up and who will likely have the most snow. Remember, there are ranges of snow totals because snow amounts vary wildly over a short distance.
When it ends
Between 1AM and 4AM the entire system pulls east, the snow ends and skies start to clear. Cold weather returns behind the system for two days. Highs Sunday and Monday only reach the 20s.
Tuesday night or Wednesday, we have the next storm with more snow or snow and rain, this looks to be light. I’ll have details over the weekend. It does turn milder after that and I promise highs reach at least the 40's by the end of the week.
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