National Weather Service United States Department of Commerce

The San Joaquin Valley Air Pollution Control District has issued an Air Quality Alert valid until 11 AM PDT Monday, September 27th for Merced County, Madera County, Fresno County, Kings County, Tulare County, Stanislaus County, San Joaquin County, and the San Joaquin Valley portion of Kern County. This Air Quality Alert is due to smoke impacts from ongoing wildfires throughout California. For additional information, call your local San Joaquin Valley Air District office. Modesto 209-557-6400, Fresno 559-230-6000, and Bakersfield 661-392-5500. Residents can also follow air quality conditions by downloading the free Valley Air app, available in the Apple store or Google Play.
The fifth wettest day ever observed in Fresno during the month of September occurred one hundred and seventeen years ago today.


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Upper Air Observations

Decoded Upper Level Winds

Plotted Upper Air Soundings

GOES Derived Atmospheric Vertical Soundings

Alternate Sources for Upper Air Soundings
Ohio State

California Wind Profiler Data Can be Found Here

Why Do Forecasters Still Rely on Weather Balloons?

Twice every day, from nearly 100 locations in the United States, the National Weather Service launches weather balloons, carrying instrument packages called radiosondes. Radiosonde sensors measure upper-air conditions such as atmospheric pressure, temperature and humidity, wind speed and direction. The data is important for aviation safety, and meteorologists use radiosonde information to prepare weather forecasts.