If you’re a skier in Tahoe right now, the weather is not making you happy. Actually, if you’re just about anyone in Tahoe right now, the weather is totally bumming you out. One of the main reasons we live here is cause it snows… A LOT. This year’s drought has been boggling a lot of us so I decided to get to the bottom of it. I went to the guys that actually make the weather.
Zach Tolby is a meteorologist at the National Weather Service in Reno, Nevada. He and his fellow meteorologists are also bummed about the weather. Against his better judgement he agreed to do an interview with Unofficial Networks.
- Zach sitting in front of 1/3 of his computer screens.
Can you tell me what is going on with this weather? The people need to know! I thought this was supposed to be another massive La Niña year.
Last year was a strong La Niña with the stationary high pressure further south and west of the coast allowing the jet stream and associated storm track to drop out of the Gulf of Alaska and bring copious amounts of precipitation to the Sierra. This season the La Niña signal is weaker with a high pressure ridge over the west coast allowing very little precipitation to make it to the Sierra. It is important to understand that La Niña can either be wet or dry and rarely brings average precipitation to the Sierra. There are other oscillations that couple with La Niña and have an impact on whether we end up with above or below average precipitation.
What other patterns would be helpful to mix with La Niña?
Other oscillations that affect the large scale patterns are the AO (Artic Oscillation), PNA (Pacific-North American Oscillation), the PDO (Pacific Decadal Oscillation), and the MJO (Madden Julian Oscillation). Besides the PDO the other oscillations are difficult to predict past 1-2 weeks and how they modulate the ENSO (El Niño Southern Oscillation) is not well understood. Also when you overlay ENSO with other oscillations you end up with only a couple years in each category making it difficult to find strong correlations.
So what can we expect out of the rest of this season for storm activity? Are there any trends that you recognize?
That’s the million dollar question. It is very unlikely to stay this dry for the rest of the winter, but how wet it will get is extremely difficult to predict. La Niña is forecast to weaken and become more neutral into spring. Once we get the ridge of high pressure to break down or shift, we should expect more typical winter storms for the rest of the winter.
- …if we could just get that black blob of high pressure to take a vacation further west. Photo: Zach Tolby.
Might this season share some of the same patterns as the Miracle March years of 1991 and 1982?
We very well could have a Miracle March, right now I am hoping for a Fabulous February. However, we are still in a moderate La Niña and both of those years were ENSO neutral.
Is the weather getting weirder or is it just me?
It is very difficult to quantify how much the weather is getting weirder, or more extreme. We do know that the frequency of billion dollar weather related disasters in the United States has been rising since 1980. 2011 had the most billion dollar weather related disasters on record with 12, killing 646 people and causing about 52 billion dollars in damages. Locally we have noticed shorter snowpack duration in the Sierra and wildfire seasons starting earlier.
Do you find that it is getting harder to predict the weather or are advances in technology and more data inputs making it easier?
Advances in technology, data acquisition, and our overall understanding of weather systems have led to continued improvement in forecast accuracy.
You release a weather balloon into the atmosphere every day. What does it do and how does it help you predict the weather?
The weather balloons launched twice a day from the National Weather Service in Reno gives us important information on the profile of the atmosphere. The radiosonde attached to the balloon collects temperature, pressure, humidity, wind speed and direction. It provides real- time data critical for forecasting local phenomenon including thunderstorms and downslope windstorms. The data is also immediately ingested into computer models that we incorporate into our forecasts a few hours later.
How many balloons are there worldwide?
There are 92 sites run by the National Weather Service and approximately 800 worldwide.
Are there any countries that don’t do this or don’t share their balloon data?
Not all countries in world launch weather balloons, many in the northern hemisphere do. The cool thing is that we have international agreements to all launch our balloons at the same time to get a snapshot of the atmosphere that can be incorporated into computer models.
What happens after the balloon pops?
At the end of the flight around 100,000 feet the balloon pops and the parachute opens bringing the radiosonde safely back to the ground. The radiosondes are made to be re- usable. If you find one you can return it to us using the return shipping envelope inside the radiosonde and it will be re-furbished. Nationally less than 20 percent are found and returned.
Well, thanks to you, Zach, and your co-workers at the NWS for all your hard work. Hopefully next time we talk you’ll have some good news about the weather!
If you are still thirsty for weather info check out the links below:
3rd driest December on record according to:
Upper air tour website
El Nino/ La Nina website