Friday 9 AM
This video shows the basis for predicting the break in the heat, as well as what may happen early next week.
On this map of the barometric pressure pattern, the basic flow is from the west-southwest. This flow will bring air downhill from the Appalachians to the East Coast. When unsaturated air descends, it warms about 5 1/2 degrees per thousand feet. This will add to the heat in the major I-95 cities today. The same wind direction over Lake Erie brings the most intense lake-effect snow right into Buffalo. However, in summer, the lake cools the air. So, while surrounding areas have been in 90s the last few days, it stayed in the 80s downwind from Lake Erie.
I mentioned snow a moment ago. It may be just a coincidence, but some of today's record highs were set in 1977. The following winter brought heavy snow to the I-95 corridor from Philadelphia to Boston, and included the Blizzard of '78 in Providence and Boston. Saturday Night Fever also came out that winter but it did not snow in that movie (although there was the glittering light created by disco balls).
It is freezing cold in the Northeast this morning, but this map shows that much more mellow mildness has reached the Plains.
Extensive precipitation straddles both sides of the cold front that was moving through central New York and central Pennsylvania as of mid morning. This radar shows the distribution of rain and snow; some temperatures are added.
The cold front approaching the East shows up quite well in this pressure analysis. Several temperatures are plotted to give you a sense for how much the temperature changes behind the cold front. At Chicago, it went from 60 at 4 a.m. to 39 at 5:19, a 21-degree drop in little more than an hour.
Temperatures on Sunday and Monday will range from the 60s in parts of New England to near 80 in Maryland and Virginia. However, a strong cold front will then trigger and perhaps a few thunderstorms as it ushers in air that will be 30-40 degrees colder than it will be ahead of the cold front.
During the early morning hours of April 15, there will be a total lunar eclipse visible across North America. This eclipse is the start of a <em>tetrad</em>, a series of four total lunar eclipses over a two-year period. The totality begins at 3:07 a.m. ET, 2:07 a.m. CT, etc.
Severe Weather Awareness Week activities are conducted by National Weather Service offices nationwide at various times during the spring. There is a lot of information for everyone (from children to seniors) available online. You can start <a href="http://www.ready.gov/kids/know-the-facts">here</a>: