Friday 8 a.m.
Today's video addresses the changes that are likely to affect the Great Lakes and Northeast between now and late Monday.
For weekend planning, anyone going camping should have rainwear just in case. In the I-95 corridor, tomorrow should be a fine summer day; Sunday could feature thunderstorms. Around the Great Lakes, it will feel like early autumn (both days of the weekend on lakes Michigan and Superior; Sunday around the eastern Great Lakes).
This satellite picture shows two main rain-producing areas. One affects New England now; the other is moving east from the Plains. The system in the Plains is quite volatile, with some places getting little rain and others getting hit by flash floods. At Fort Sill, Okla., 2 inches of rain fell in about 10 minutes early this morning.
The area circled in red is the system now causing rain in New England. The area outlined in black contains hot spots where it is pouring and other areas that are free of rain.
The clouds scattered from Montana to South Dakota formed in response to a cool patch of air aloft that will join and perhaps strengthen the frontal zone in the Midwest (where little is happening on this picture). The southern portion of the front is much more active, with violent thunderstorms and cloudbursts of rain. Whatever that system looks like later, it will be over Georgia and the western Carolinas tomorrow night and Sunday.
A number of you have submitted weather photos and graphics that we really enjoy. One person with a keen eye for how to visualize weather and climate events is Ralph Fato of Connecticut, who graciously allowed me to use this graphic about snowfall.
Snowfall amounts yesterday were low from Philadelphia to New York City. Accumulations increased toward the north and northeast.
This map shows the NAM's projection for this Friday night. The isobaric pattern suggests there is a southwesterly flow of mild air from the Gulf states to the Middle Atlantic region. Farther north, we see evidence of the frontal boundary that separates the mild air from chillier air.
A new area of snow now over southern Minnesota should expand southeastward to reach Chicago this afternoon, streak to Pittsburgh this evening, then reach the Philadelphia/New York City area late tonight or early tomorrow morning. This map shows a low pressure area over Missouri.
This map shows expected accumulations.
Check AccuWeather.com's latest info as the forecast ideas mature. This is a draft of the Thursday morning snow accumulation idea.