December California Summary and Wet Weather Forecast Tools

December Summary and Forecast Tools


The December California Summary was highlighted by some stark contrasts in rainfall around the state while temperatures were pretty close to normal. In the SF Bay Area, downtown San Francisco rainfall was 14% above normal while San Jose was 15% below normal. (So the average of the two would be normal?)  Elsewhere north of the Tehachapis, rainfall was generally well above normal, with 180% of normal at Eureka, 168% at Fresno and 131% at Redding; but Sacramento was the outlier with only 50%of normal. 

I have put together a simple map interface to access the "sampled" GFS for locations around California. See  

While the GFS is not always the best model,especially out past about 5 days, the sampled data gives a good quick "first guess".  For example the "Total Precip" column is an easy way to see the timing of an approaching system. And if any of the values on the page are underlined, you can click through to see the associated charts. Previous QPF amounts can also be compared at

The QPF page has been updated and hopefully all the links are working. Lots of rainfall and river resources to be aware of and hopefully used often in the coming months.

Happy New Year.

Jan Null, CCM
Golden Gate Weather Services