We are wrapping up February on a mild note, however still not above average. In fact, the last time the high temperature rose above average was on the 20th (average: 39F, actual: 41F), and the only other time before that was on the 2nd (average: 33F, actual: 37F). For the month of February so far, the high temperature has averaged 27.0F, which is 7.6 degree F under the February 50 year average of 34.6F. While the records are still being examined, in many areas in the Northeast and Ohio Valley this February has marked the biggest turn-around in temperature in history. The months of December ('06) and January ('07) were extraordinarily warm if you will recall, with the high temperature averaging over 8 degrees above the normal for December and over 12 degrees for the first two weeks of January. Then the weather underwent two changes, the second being the most drastic. The first one came on the 15th of January behind a storm that coated Keene, NH in a quarter inch of ice. The temperatures moderated somewhat closer to average and that lasted for two weeks, which did allow some light accumulating snow events to occur. January still ended with the high temperature nearly 3 degrees above the monthly norm. February greeted us with our first notable snowfall event. Groundhog's Day (on which one bold little groundhog said winter was ending early) featured a coastal storm that went well south of the region, but a northern storm that relit the hopes of snow-lovers by dumping 4.4" of snow that night. What happened behind the storm was more important however, as the AO finally dove into the negatives allowing a surge of arctic air which threatened records all across the region. It also opened the gates for one of the largest Lake Effect Snow events in history to occur in western NY state. Keene ducked under zero a couple of times and highs stuggled into the low teens a couple of times, but the general gist of the temperatures from the 2nd through the 20th was highs around 20 and lows around 5. On the 20th, Mother Nature realized "Whoa, I can't keep doing this. I only have a month left to warm up to spring." So down went the PNA, which meant troughiness in the west, and a build up of a SE ridge. Even though the ridge pushed the arctic air out, New England still kept hold of the cold as the AO refused to budge and in fact bottomed out at -2SD on the 20th again. By the 22nd, the AO started to rise back toward neutral, and at this point it is just above -1SD. Oh and by the way, the NAO stayed neutral (within +/-0.5SD) since the 29th of January, so blocking was minimal through the month.
The Forecast:
Temperature:
Temperatures won't move too much as we approach the start of March. As you might have already figured out, a significant storm will affect us on Friday. Behind the storm, temperatures will stay warm as a low to our west continues to boost temperatuers. Saturday we could peak in the low 40's again, but nothing far from average (as that IS the average). However, a slow return to cooler temperatures will ensue on Sunday, and by Monday we will be seeing highs back to the low to mid 30's and possibly not excaping the 20's by late next week. This cold will hold strong (enhanced by a rising PNA and a breaking of the SE ridge) through the 7th. By the second week of March, a steadily rising AO and a slow resurgence of the NAO will create a ridge over the eastern two thirds of the country. In fact, most of the nation will be above average through the middle of March. Here in New England, we will be on the eastern edge of the heat dome but will still see highs averaging 4 to 6 degrees above normal through the 20th. A drop in the NAO will mean moderating temperatures as we close the book on March. By April, we may actually see a genuine negative NAO (a little late if you are a fan of nor'easters) but it may still by on time to help winter keep a grip on northeast US through mid April. We may even see one last 4+" snow event in April (which of course isnt that uncommon, but I dont want to jump the gun on 6+).
Storminess:
The start of March will be stormy... as we can already tell by looking at the medium range forecast period. Another storm behind this week's event could add to the snowpack a little, and then we will likely have another storm around the 7th as the pattern goes warm. I have my doubts on anything significant coming with this storm. As I see it, we'll get some showers and some sleet, and then the warmth comes. With the warmth will also arrive a drier pattern. As I had said before, we will be on the eastern edge of the ridge, this means that even with warmth, we will be denied access to the moisture load in the south. All the storminess during this period will occur in the southern plains and Ohio Valley, in association with the southern jet. The northern jet, which will be lifting into Canada will not have admittence to any of the Gulf moisture because it will stay relatively flat even out west. In New England especially, it will be dry because the storm flow will be out of the west and northwest which might pull some dry shortwaves out of Canada, but all passing north of the region. By late March, the NAO will decide it wants to try being negative for a change and finally plant a trough over the east. This will open up the southern storm flow, but the focus will still be to our south in the Mid Atlantic region. We will however have access now to the a renewed flow of storms across Canada and into New England. One of these, in fact, will probably be the storm to instigate the pattern change between March 24th and April 3rd. April will see average precipitation to start, probably some a few light to moderate wet snow events through the 10th. The storm flow will start drying out again however as we enter the middle of April.
National forecast:
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