http://weatherstation.wunderground.com/weatherstation/updateweatherstation.php

action [action=updateraw]
ID [ID as registered by wunderground.com]
PASSWORD [PASSWORD registered with this ID]
dateutc - [YYYY-MM-DD HH:MM:SS (mysql format)]
winddir - [0-360]
windspeedmph - [mph]
windgustmph - [windgustmph ]
humidity - [%]
tempf - [temperature F]
rainin - [rain in (hourly)]
baromin - [barom in]
dewptf- [dewpoint F]
weather - [text] -- metar style (+RA) 
clouds - [text] -- SKC, FEW, SCT, BKN, OVC
softwaretype - [text] ie: vws or weatherdisplay