Revelations And Reservations
Would you like to be rewarded for enduring this astonishing, relentless winter? Well, you can now brag that you lived through historical times in Boston's snowiest season ever with records dating back to the winter of 1890-91! It became official just after 7pm Sunday as the National Weather Service reported that Logan Airport received 2.9" of fresh snow in occasional near whiteout conditions for about 3 hours. That boosted the seasonal total from 105.7 to 108.6". These heavy snow showers erupted as an upper level low pressure system and associated pool of cold unstable air passed across eastern New England in tandem with a north-south coastal trough where convergence and extra lifting existed. This convection triggered lightning and thunder in a few locations over southeastern MA!
So, now that we got the gold medal, you might say it's time to move on and time for the switch to immediately flip for us to enjoy instant spring. After all, look how warm the rest of the nation was on Sunday. Once again, we were in the cold corner of the country. Despite some melting last week with a max of 57, the overall weather pattern still favors masses of cold air charging out of Canada into mainly the northeastern portion of the United States. Additionally, global factors in play matched with analog years suggest that a few more snow threats may be in the works. This is not a definite forecast yet but we need to closely monitor upstream atmospheric perturbations. Any one distinct short wave has the potential of developing a wave of low pressure which could impact the region. Over the next few weeks, the southern stream will be busy with its batches of moisture and the northern stream will continue to conveyor belt the cold into our area. Any phasing of the streams will be a problem. The seasonal shift of the jet stream eventually will deliver some warmth that we deserve but patience is still required. At mid-month, March is running about 4 degrees below the average but I am much more optimistic about April turning out near to somewhat above average in temperature with a similar outcome for May.
The main driver of the weather last summer through this winter has been the warm water of the eastern Pacific Ocean. This produced a semi-permanent ridge of high pressure near the West Coast of North America resulting in downstream winds distributing masses of air containing below to much below average temperatures from Canada into the eastern portion of the country. Latest modeling guidance indicates that warm water is not going to modify and turn gradually cooler. Additionally, the sea-surface temperatures of the Atlantic are projected to decline and that is a switch from last year. Overall, these oceanic events imply ridging remaining rather dominant out west and troughing near and offshore over the western Atlantic. The conclusion is to prognosticate a June-July-August anomaly of below average temperatures. Last year, while the months of May, June and July all were slightly under a degree above average, the mean temperature of August was more than a degree below average. For many of us, it was one of the most comfortable summers in many many years which prompted complaints from those folks who crave hot weather. Amazingly, there was not a single heat wave in Boston last summer. There were only 8 days at 90 degrees or higher which compares to the average of 14. I am predicting a summer that will more likely mimic last summer so 8 to 10 days at 90 or higher in Boston with closer to 14-16 days farther northwest of Boston. Contrast that with the super hot summer of 2010 that featured 25 days at 90 or higher with more than 30 days in some inland towns!
In the short term, after near average temperatures tomorrow and St. Patrick's Day, another shot of arctic air will blast us on Wednesday with temperatures not reaching 32 in most locations. The strong wind will make it feel like the teens! After that, we can look forward to the official beginning of spring at 6:45 pm on Friday.
Make it a great week!
