Many new record maximum temperatures were established in New England today and a few of them smashed the previous highs by about a half dozen degrees. Case in point is Nashua, NH where it surpassed 64 to reach 71! Most of the WBZ WeatherBug Network stations depicted highs of 68-74 except near portions of the coastline and over most of Cape Cod. These are the average high temperatures for May 27 not March 12! Plus it felt warmer than last Thursday’s records in the upper 60s when the wind was gusting to 45-50 mph. Boston’s 2:03pm max of 71 eclipsed the 69 set in 1902. At 3pm, it was still 71 but the wind then flipped to a sea breeze so the 4pm temperature was down to 59. This was a typical development along the coast and is a sign of things to come. However, it looks like one more warm day should be squeezed out before the cold ocean takes control and rules the rest of the week. Approaching frontal boundaries will produce patches of insignificant showers late tonight and tomorrow. Much of this time will be dry but there is a risk of a bit of wet weather mainly in spots during the morning commute and again later in the afternoon, Between these spells, the cloud cover should break up to allow some splashes of sunshine. If the periods of sunshine are longer-lasting, it could warm up to or even exceed 70 again in many areas away from the South Coast and outer Cape Ann. This is assuming that a floppy light south-southeasterly breeze will shift into a southwesterly direction during the morning. Boston’s record high for March 13 is 73 set in 1990. Meantime, another southbound cold front over northern New England this evening will become quasi-stationary overnight waiting for the passage of the other systems tomorrow. Once that happens, the cold front gets the green light and begins shifting southward again and should pass the Boston area by dawn on Wednesday on its way to the South Coast by midday. The resultant northeasterly surface breeze will make all the difference in the world. I expect a deck of low clouds to fill the sky and linger through Thursday night. As the ocean gains control, the temperatures will fail to rise much above 50 on Wednesday and the middle to upper 40s on Thursday when some mist may get into the act. Building high pressure in the Canadian Maritimes will shove this cool moist air into New England. That will be followed by the next disturbance arriving from the west to create more spotty showers on Friday. Unfortunately, no widespread beneficial rain is anticipated from this feature either so our 2012 precipitation deficit will increase in the weeks ahead. After this feature exits, another zone of high pressure over Ontario will begin to build gradually toward New England.
Looking ahead, this high pressure system will become poised over the Northeast on Sunday and Monday as an anomalous giant upper level high pressure system blossoms in the region. The air mass will be warming substantially aloft. Initially, it will be difficult to warm up over the coastal plain at the surface due to a flat pressure gradient and vulnerability to cooling sea breezes. Eventually, as the surface high pressure shifts south of New England, the anticyclonic circulation will steer much warmer air into the region toward the coastline next Monday, Tuesday and possibly Wednesday. Potential temperatures in this setup are 75-82! Surprisingly, Boston’s record highs are 72 for March 19, 79 for the 20th and 83 on the 21st. Due in part to this being a leap year, the vernal equinox or the official astronomical start of spring is the earliest in 116 years at 1:14am on the 20th.
Melissa Mack delivers her AccuWeather Forecast in the morning and Todd Gutner returns from vacation later in the day.
Make it a great Tuesday.