Friday 9 AM
Sandy continues to threaten the Northeast, and in the area where is comes ashore, there will be damaging winds knocking down trees and cutting power, flooding rain and, at the coast, a dangerous storm surge. Time of that is crucial, because we will be close to the time of the full moon, and range between high tide and low tide is greatest then. This map shows the track forecasts of a wide variety of computer models. Why the differences? Each one has its own way of ingesting data and handling the intricate math associated with second order nonlinear differential equations. A big problem is we simply do not have data for every place in the atmosphere.
This video discusses where the storm is heading now, what should happen next, and what some of the effects will be. Unfortunately, this kind of storm can affect millions and cost billions.
It appears the dry comfortable air mass now in the Northeast will be replaced by a humid flow from the South Atlantic states for the coming weekend. An upper-air forecast map sequence in the video shows how this could happen. The following map shows the predicted flow from Florida to New Jersey Friday night.
This map shows the pressure analysis for the Northeast and Great Lakes. The gusty flow on the west side of the low pressure area adds a real autumn feel to the air.
Since individual lines and clusters of thunderstorms have limited life spans and change character constantly, forecasting whether it will or won't rain at any one time this weekend is difficult at best. One solution is to have your tablet or phone available with the AccuWeather.com app so you can see where all the storms are at the times when it concerns you the most.
It does look warmer for the weekend, but every time the warm air tries to extend into New England it gets chopped down. There could be more showers at times Sunday and early next week as forest we can tell. If any forecast gives you a headache, why not take a friend's advice: Take two aspen; sequoia in the morning.
This map from 5AM ET shows the cold front that is continuing toward this Northeast and Middle Atlantic states. Temperatures stayed up in the 70s all night ahead of the front but it turned noticeably cooler after the front moved through.
The cold front that will cut off the heat will generate strong gusty thunderstorms as it moves southeastward today. The National Weather Service Storm Prediction Center highlights the most likely area for these severe thunderstorms today and tonight.