Thursday 8 a.m.
Showers and some thunderstorms reached Delaware, southeastern Pennsylvania and southern New Jersey early this morning and could reach Boston by the end of the day. With additional moisture feeding into this system from the south, we can expect some of the rain to cause flash flooding on streets and highways, as well as other places that do not drain well.
Dry air is likely to seep into the DC to NYC corridor to make tomorrow a nice day. However, another front from the northwest could being more showers to the same areas for part of Saturday and Saturday night. If that timing proves to be right, Sunday would feature the return of sunshine with low humidity.
No heat waves are likely in the Middle or North Atlantic states in early August, but we cannot promise the heat never comes back. An extreme example of a reversal affected the middle of Pennsylvania in 1918. At State College, the low on Aug. 1 was 45, then the high on Aug. 5 was 99! Here is the morning video.
In late July, before-and-after pictures taken from an Arctic webcam were posted on the internet and some people claimed it proved global warming was accelerating. This article, written by AccuWeather.com Staff Writer Jillian MacMath, shows there is more to the story. You can read it now!
The map below shows areas with showers and thunderstorms at 9 a.m. EDT. You can see the rain from Maryland to southeastern New York, as well as a band of showers farther west.
This map shows a draft of our starting time lines and expected accumulation from tomorrow's quick-moving East Coast storm.
A storm that has brought hardship and danger to parts of Texas and Arkansas with an assortment of ice and snow will send a swath of snow northeastward today and tonight. Here is a map showing our overall estimates as of 10 a.m. ET:
That could lead to tough travel at the end of the weekend. This map for Sunday at 7 p.m. ET shows where those troubles could be (north of the line with the label "snow rain line.")
This table shows the ensemble means for the next two weeks at Philadelphia: It suggests that whereas it does turn cold, any snowfall looks quite limited.
It is too early to be confident about any forecast for Christmas Day (or even the week before). However, the GFS model does go out 16 days, and it has a cold look for the Northeast exactly one week before Christmas.
As the flow aloft becomes southwesterly, mild moist air will spread northeastward from the Gulf States. In summer, this creates a hazy, very warm and humid scene for the Northeast. Now though, the warmth is slowly drained away as the moist mild air advances over cold ground. With temperatures near the saturation point, clouds form.