Forecasting a storm's intensity can be more challenging than predicting where it will make landfall. Forecast models, particularly for hurricanes, have improved, but they can still miss intensification or overstate it. Below is the intensity for Erin so far, and how experts at the Hurricane Center believe it will weaken or strengthen.

The outer bands of powerful Hurricane Erin lashed Puerto Rico, and the storm is approaching the Bahamas next. What can the mainland U.S. expect?

A disturbance in the Atlantic following Hurricane Erin is now expected to track northward, National Hurricane Center data shows.

The National Hurricane Center expects Hurricane Erin to pass just north of the U.S. Virgin Islands and Puerto Rico this weekend, bringing the potential for flooding, hazardous seas, and tropical storm-force wind gusts as outer rainbands sweep across the region.

Forecasts nudge Erin's likely path to the west, increasing the risks at U.S. beaches. Tropical storm conditions are expected in North Carolina's Outer Banks starting late Wednesday.