As any knowledgeable pilot will admit, weather has so many variables that it must be learned in the cockpit. You can learn some theory and begin to understand some of the basic workings from the other sources, but it is only after flying cross-country for some time that pilots begin to develop real weather judgment. Past experience must be applied with caution. What looks like a similar condition for a particular flight may not be. One of the major changes in the weather equation is how pilots get weather information.
Flight service is the starting place for many pilots.
Flight service has changed from the small stations that, decades ago, were located all over the country and typically staffed with pilots and other weather-savvy folks. Today, large automated facilities are populated with civil servants, some of whom are incapable of interpreting weather for a pilot. In many cases they are reluctant to go beyond reading the forecasts. If the forecast is in error and conditions are changing, many briefers will not extrapolate or make an educated guess until a new forecast is issued. Occasionally you can find a briefer who will go out on a limb to provide some sage advice, but often a question will be answered with a rereading of the warnings.