Roller Coaster Time
Boston’s 1:29pm maximum temperature of 63 degrees yesterday was the highest since November 12th when it struck 66. Then as the afternoon progressed, the blossoming sea breeze caused the typical coastal cooling with a drop back to 55 at 4pm and 52 at 5pm. Nevertheless, it was a splendid day for the home opener at Fenway Park capped off with a great win over the Orioles. The evening games Wednesday through Friday are all threatened by rain so I suspect that at least one of them will be postponed and the most likely one will be Friday’s contest. In the meantime, after this morning’s rude awakening of brief downpours, thunder and even some pea-sized hail in some commmunities, there will be a dramatic change in the weather later this morning as drier air finally arrives at lower levels to clear out the murky conditions. There is plentiful warm air aloft and with a developing downsloping wind later, the stage is set for temperatures to soar to 70. The last time it reached or exceeded that level was back on October 20 when the max was 74 in Boston. The record high for today, April 9, is 85 which was set in 1991. Far northern New England will be considerably cooler this afternoon in the 50s to lower 60s.
Cooler air will be seeping into the region later in the day as the next wave of showers approaches from the west. It will shift over the region late tonight and exit first thing tomorrow morning. Unlike today, I am not expecting much clearing behind that batch of rain. There could be some spotty brightening and perhaps a few splashes of sunshine but the frontal boundary will be strung out south of the area and a light northeasterly wind will prevail. That means that highs will be a solid 15 degrees lower than today. I doubt that it warms up much past the upper 40s to near 50 at the coast to the middle 50s inland. Beyond that, it gets even colder. A cold front settling into southern Canada later today will gradually push southward into northern New England later tomorrow and southern sections on Thursday. As high pressure builds across southern Canada, the pressure gradient will tighten and the resultant wind will be ramping up a bit. With additional waves of low pressure transiting along the frontal band, our area will be vulnerable to occasional to periodic rain of mostly light to moderate intensity until the main low pressure system closes in on the region later Friday and Friday night when the rain becomes haevy at times. A primary low center which will track into the eastern Great Lakes and a secondary low will form over Delmarva Friday afternoon then move up over outer Cape Cod later Friday night. As colder and colder air is drawn southward, it should become sufficiently cold to cause a phase change of precipitation to some ice pellets and snowflakes into northern MA. Over northern New England, accumulating snow is probable especially over the higher elevations where several inches are possible. I cannot rule out 1-3″ of snow down into the highest elevations from northwestern Worcester County west and north!
Looking ahead, once the storm passes over the Gulf of ME early Saturday, drier air will cause partial clearing later that morning with some sunshine returning. A couple of upper level perturbations may set off a brief shower later Saturday and possibly again on Sunday but, for the most part, the weekend should be on the dry side with temperatures rising to the middle to upper 50s. After that, an approaching warm frontal boundary will likely produce some cloudiness on Marathon Monday and Patriots Day. This is not a high confidence forecast yet but, right now, it looks like there is a slight risk of a shower associated with the passage of the warm front. With this happening, it could easily warm up to at least 65-70 with some sunshine Monday afternoon. The wind would switch from southeasterly in the morning to southwesterly in the afternoon. More specific details will be forthcoming from subsequent forecast cycles later this week.
Todd Gutner posts a fresh update later this afternoon or early evening and I shall return tomorrow morning.
Make it a great day!