Friday, February 13, 2015

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Holy Inversion Batman!

I'll start by being straight forward and saying that we have no hope of any significant (or weak, really) storms within the next 7 days. The figure below has been way too familiar this winter over the western US. White blob of nothingness over the Sierra Nevada, boo!

That doesn't mean there is nothing interesting to talk about weather wise. The persistent ride of high pressure over the west has led to some rather extraordinary temperature inversions for the Reno-Tahoe region. The sounding, showing weather balloon data, from the Reno NWS office is shown below. Weather balloons are released twice a day around the globe at exactly the same time, which provides valuable input data for the atmospheric models that produce our forecast. Pretty amazing!

Even more amazing is the strength of the inversion found in the vertical profile, and just the general nature of the early morning heat wave. The x-axis of the graph is temperature (red line air temperature and green line dew point temperature) and the y-axis is elevation (pressure units are shown in mb, but that is easily translated to elevation, and 700 mb is ~10,000 ft.). At the surface, the temperature was about 45 F at 4:00 AM and a whopping 55 F at ~7500'. Toasty!

Figure: Sounding from Reno NWS at 4:00 AM on 2/13/2015. Source:

Figure: The yellow dots show the locations of all the global sounding release points. At each location a balloon is released at 00Z and 12Z every day.

This inversion translated to some really warm temps at the ski resorts this morning. Check out the Alpine Meadows sensor at 7800'. It was 65 F at 9:00 AM today! There is basically no hope for a good corn cycle in the near future, until we start to get down near or below freezing at high elevation overnight.

This could turn out to be a fun weekend for resort skiing, pond skimming, and beer drinking. Get it while there is still snow!

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