From National Weather Service -

This page provides access to NWS watches, warnings, advisories, and other similar products several different formats. Select a state or product name to view a list of active alerts in your web browser. These files are updated about every two minutes. Tropical Prediction Center/Storm Prediction center feeds are updated on an as needed basis. RSS and CAP/XML lists based on state and NWS forecast zones are provided to aid the automated dissemination of this information. More information on RSS and CAP/XML formats/feeds. This is an experimental product of the National Weather Service. Comments and feedback are welcome. A Product Description Document is also available.

Finally! NOAA has an RSS feed!