This October has been characterized by incredible autumn weather. It has been warm, sunny, and dry. To date, Boston has recieved only 0.50 inches of precipitation, which is over 2 inches below normal. Additionally, much of October saw high temperatures above average, except for October 9-14, which saw high temperatures right around average. The overall monthly average temperature through Oct. 20 is 60.5°F, which is 4.8°F above the climatological average.
A rather complicated forecast situation has set up for Friday. While we all had hoped that the high pressure (which brought us gorgeous weather on Tuesday and Wednesday) would stick around for Commencement, Mother Nature has other plans in mind. A low pressure system moving from the Ohio River Valley into our regions brings the first threat of rain today. Complicating this though, is a tropical system, which as of 6 p.m. Wednesday was classified as the first tropical storm of the 2013 Atlantic hurricane season; Tropical Storm Andrea. This system will interact with the low pressure from the Ohio River Valley as well as with an upper level trough to bring heavy rain today and tomorrow. With abundant tropical moisture, we could receive several inches of rain. As of this writing, there is still significant forecast uncertainty regarding the track of this system, the timing of its arrival in the Northeast, and the location of the heaviest precipitation. It seems that the heaviest precipitation will not be until tonight, but there is, unfortunately, a chance of rain during this mornings Commencement ceremony. As the system heads out to sea tomorrow, the rain should taper, with dry weather expected on Sunday.
The below average temperatures of the last two days will continue today, with a coastal storm set to deliver a damp and chilly day. With high temperatures probably not making it out of the 40s°F, rain likely throughout the day and evening, and a cold northeast wind, it will not be a particularly pleasant spring day. However, it looks like the situation will improve for the rest of the week. Tomorrow is our best chance for some above average temperatures, with a southwesterly wind advecting warmer air into our region ahead of an approaching cold front. Some rain showers are possible with this cold front tomorrow evening and Thursday morning. Thursday and Friday, building high pressure will keep the weather mainly dry with seasonable temperatures near 60°F.
Yesterday’s weather was glorious, with temperatures at the weather station on the roof of the Green Building reaching 65.1°F. We also experienced a common Boston spring and summertime phenomenon for one of the first times this year — the sea breeze. Around 4 p.m., the winds shifted from northwest to east. With the winds now coming off the ocean (with sea surface temperatures still in the 40°Fs), the temperature at the Green Building plummeted by 10°F in a little more than an hour.
The high pressure system that has been parked over the Northeast for the last few days will remain in control of our weather through the end of the week. It will continue to be dry and seasonably cool (highs around 50°F). Onshore flow off the ocean today and tomorrow will advect some moist air, causing some cloudiness. Thanksgiving looks to be a pleasant day, with mostly sunny skies and highs in the low 50°F’s expected. The high pressure will finally move away from our region on Friday, with a cold front approaching from the west. Southeasterly flow could allow temperatures to make it into the mid 50°F’s. Looking ahead to the weekend, the cold front is expected to move through on Saturday, but shouldn’t bring a great deal of precipitation. Following that, Sunday will be much cooler and breezier.
Over a week later, the Northeast is still recovering from the impacts of Hurricane Sandy. With many people not regaining electricity until the last few days (and many still without), the recent cold temperatures have been especially unpleasant. Today will be another chilly day, with temperatures in Cambridge only reaching the mid 40°F’s.
The National Weather Service has confirmed the intensities of the three tornados that struck western Massachusetts last Wednesday, June 1. The strongest left a path of devastation 39 miles long, from Westfield to Charlton, and was half a mile wide at some points. That tornado was classified as an EF-3, the third-highest rating on the scale with estimated maximum winds of 160 mph — a rarity for this part of the country. Two shorter-lived EF-1 tornadoes were confirmed in Wilbraham and North Brimfield.