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.
it appears a storm will form the Southeast and trek toward eastern New England this weekend. Current models suggest this will turn into a mostly rain event in the I-95 corridor...
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.