Tuesday 8 a.m.
When the temperature reaches a high or low reading that is higher or lower than any previous temperature on record for that date, a new record is established. When the weather is truly extreme, records set during that period represent a high bar for subsequent record attempts. Take Boston, for example. In 1881, the temperatures soared to 102 degrees there on Sept. 7. That's the highest reading for any day in September, and it came later than the other two 100-degree days in September, the 2nd and 3rd in 1953. On the low end, before today, the record low for this date (Sept. 17) in Boston was 45 set in 1986; 45 degrees represents the highest record low for any date in the last half of September, so we could say it was vulnerable. This morning, the temperature dropped to 44 degrees at Logan International Airport (symbol BOS), setting a new record. The record high for the date is 91, set in 1915.
The year 1915 (as does any year before 1923) raises an issue about where the official Boston records are and were kept. The Boston airport was first used for landings on June 13, 1923. In 1927, Colonial Air (a predecessor to American Airlines) started the first commercial service between New York City and Boston). Until Logan was established as the official record keeping site for Boston, the weather records were kept at a city location (as was the case in many cities before airports came into existence). This raises the question of how representative various records are because they may have been taken at changed locations with different characteristics.
Here is today's video forecast:
Looking at the tropics, there is activity, but most of it so far has not affected the U.S. mainland. The H storm, Humberto, is in the east-central Atlantic and has not been well organized. In 1989 on this date, the H storm was Hugo, and it was a monster that roared ashore in South Carolina days later. In 1954, the H storm was Hazel in mid-October. The storm came inland at Myrtle Beach, S.C., and was still strong enough to knock down thousands of trees in Pennsylvania as it sped northward.
There is an area of disturbed weather near the Bahamas, and it may strengthen. A new storm could also form in the southwest Gulf of Mexico and replace Ingrid. This map shows the arrangement of features in the Atlantic basin as of early the morning.
Here's a cool fact: even when Death Valley, California, has a temperature of 110 or 120 degrees, you only have to go up a little more than 3.5 miles to find temperatures at or below freezing.
It appears the dry comfortable air mass now in the Northeast will be replaced by a humid flow from the South Atlantic states for the coming weekend. An upper-air forecast map sequence in the video shows how this could happen. The following map shows the predicted flow from Florida to New Jersey Friday night.
This map shows the pressure analysis for the Northeast and Great Lakes. The gusty flow on the west side of the low pressure area adds a real autumn feel to the air.
Since individual lines and clusters of thunderstorms have limited life spans and change character constantly, forecasting whether it will or won't rain at any one time this weekend is difficult at best. One solution is to have your tablet or phone available with the AccuWeather.com app so you can see where all the storms are at the times when it concerns you the most.
It does look warmer for the weekend, but every time the warm air tries to extend into New England it gets chopped down. There could be more showers at times Sunday and early next week as forest we can tell. If any forecast gives you a headache, why not take a friend's advice: Take two aspen; sequoia in the morning.
This map from 5AM ET shows the cold front that is continuing toward this Northeast and Middle Atlantic states. Temperatures stayed up in the 70s all night ahead of the front but it turned noticeably cooler after the front moved through.