Saturday 1 PM EDT
Sandy is still wobbling northward well off the South Atlantic coast. As a strong trough aloft approaches Sandy, the storm's circulation will be drawn into and become part of a greatly expanded upper air storm.
Since the storm will be a hybrid that includes some of the characteristics of the non tropical storms that cause most the cold season precipitation we see in the Great Lakes and Northeast, its circulation will be more spread out (rather than more compact). A lot of rain will be generated as tropically moist air is forced westward over air that is much cooler. This is something we typically do not see with pure tropical storms/hurricanes.
What all this means is that the heavy rain and increasing wind will reach places long before the center arrives. Delaware, New Jersey, as well as parts of eastern Pennsylvania and Maryland, are likely to start getting damaging winds and torrential rain tomorrow night, perhaps escalating into the worst conditions Monday morning. The center will come ashore after this, and by that time the rain and even the wind will be weakening.
Unless the storm tracks farther north than expected, the New York City area may be near the northern edge of the very worst conditions. Where the wind and rain are the worst, there will be streets flooded with water and massive tree damage and power outages. And, the wires have to be restrung one at a time... that's what takes so long (as well as other challenges of accessibility and maintaining safety.
It is important to complete your planning and preparation before the worst conditions approach later tomorrow. This video shows the situation and forecast as of early Saturday afternoon. Please check more recent information that will be continuously updated on AccuWeather.com. Also, your local emergency management people are trained on helping people avoid and deal with the most critical things that can kill and destroy.
Enhanced infrared satellite picture from early Saturday afternoon.
If the ridge was the only thing involved, it would just be sunny hot and humid day after day. As it is though, there are various minor disturbances rippling through the ridge. One such disturbance has allowed cooler air to spread down the coast.
This map shows where the storms were at 10:18 AM ET. That cluster of storms may hold together, but in response to daytime heating, new ones can pop up at other places this afternoon.
On this map, two such features (short waves) stand out today. The one in Ohio caused some thunderstorms in Michigan and Indiana yesterday. The other short wave is causing thunderstorms this morning from western Wisconsin to northern Missouri.
Scotty the Dog will be four-months-old in four days. On walks during hot weather, he is quick to seek out shady spots. He has yet to experience any cold weather, but he looks like he will be ready when it arrives (not any time soon!).
Erika's heavy rainfall separated into two areas yesterday. This is the Morehead City, North Carolina, radar, showing an area of heavy rain and thunderstorms that dumped more 4 inches of rain on parts of the coastal Carolinas this morning.
Tropical Storm Erika could eventually affect Florida and other sections of the Gulf Coast or Southeast, but for now it poses no threat for the Northeast. This map shows the storm as of early this morning.