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Severe Thunderstorms and Tornadoes Overnight in the South

An outbreak of severe thunderstorms in the Southern U.S. is expected to continue well into the overnight hours. Severe thunderstorms are bringing strong tornadoes, very large hail, and severe wind gusts across parts of the lower to mid Mississippi Valley, Mid-South and parts of the Southeast. A few long-track strong tornadoes remain possible. Read More >

Outside of major urban areas, sub-freezing temperatures are expected in most of the San Joaquin Valley tonight. A Freeze Warning is in effect. Take precautions by covering sensitive, exposed vegetation and bringing pets indoors. Here are low temperature probabilities for select locations in the San Joaquin Valley on Wednesday, November 30th, 2022.
Major winter storm impacts are expected in the Sierra Nevada Thursday through Friday morning due to snow load and snow amounts up to three feet. If you plan to travel, consider alternate strategies. A Winter Storm Warning is in effect.
The next storm system will impact Central California Thursday through Friday morning. The majority of precipitation associated with this storm system will fall Thursday afternoon and Thursday evening. Snow levels will start at around 5,000 feet Thursday, before dropping to about 4,000 feet Thursday night. A Winter Storm Warning is in effect for the Sierra Nevada.
The next storm system will impact Central California Thursday into early Friday morning, resulting in the likelihood of rain in the San Joaquin Valley. The majority of this rain will fall Thursday afternoon and Thursday evening. Here are rain amount probabilities for select locations in the San Joaquin Valley from 10 AM PST Thursday, December 1st until 10 AM PST Friday, December 2nd, 2022.
The next storm system will impact Central California Thursday through Friday morning, resulting in snow in the Sierra Nevada. Here are snow probability graphics for eight inches of snow or more, twelve inches of snow or more, and eighteen inches of snow or more Thursday through Friday morning. A Winter Storm Warning is in effect for the Sierra Nevada.

 

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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.