NWS Reno: Forecasting for the Sierra and Western Nevada Since 1905

Well the smoke has returned... it seems like an appropriate time to have Washoe County Air Quality guest blog about the smoke again. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -      Wildfire smoke contains many different pollutants with fine particulates (PM2.5) being the most concerning (see blog post "Wildfire Smoke in Northern Nevada ). The Washoe County Air Quality Managament Division's PM2.5 monitoring network has been monitoring since 1999. In addition to the two permanent PM2.5 monitors at our Reno3 and Sparks monitoring sites, we recently deployed portable beta attenuation monitor (E-BAM) for PM2.5 monitoring at Pleasant Valley Elementary to expand our network during wildfire season (see map). An E-BAM's purpose is to get accurate PM2.5 data so that the public can make health based decisions as soon as possible. Decisions like keeping windows closed at night, having recess or practice indoors, and cancelling events like a triathlon are

El Niño and La Niña are weather catch phrases that are thrown around pretty frequently, but how many of us truly know what these features are? They are complex atmospheric-oceanic circulations, and to be honest, it's more than we could even explain in a short blog post, but we will cover some of the basics here. Let's start with El Niño since we currently have these conditions in place. El Niño is the warm phase of the El Niño Southern Oscillation (ENSO) and refers to warming in the equatorial Pacific sea surface temperatures (SSTs) compared to normal. Here is a quick video explaining this phenomenon: La Niña is the cool phase of ENSO and refers to cooling in the equatorial Pacific SSTs compared to normal. One more quick video to explain: The strength of El Niño and La Niña episodes is determined by the difference in SSTs compared to normal and are measured in a region of the east-central Pacific Ocean known as the Niño 3.4 Region: The Oceanic Niño Index (

Everyone is familiar with weather radar and how it can detect areas of precipitation, but radar is also an indispensable tool when it comes to helping identify storms which have the potential to become severe. Normally when we refer to severe storms in the West, we are referring to storms that are capable of producing damaging winds/hail and also flash flooding. Here in the Sierra and western Nevada, tornadoes are fairly uncommon but still can happen as was the case this past June in Hawthorne, NV where an EF-1 tornado formed.  Smoke on Satellite   The satellite image below (fig 1) shows a true color view from the afternoon of the 8/18/13. What is notable is the smoke plume from the American Fire hovering over the Sierra west of Lake Tahoe. The next image later that afternoon (fig 2) show thunderstorms had formed across the Sierra south of Tahoe while smoke had begun to travel up slope of the Sierra.  Figure 1: MODIS-Terra satellite image from the afternoon of 8/18/13. W

Enjoy this guest post from our friends at Washoe County Air Quality !  - - - - - - - - Forecast calls for sunny skies and hot temperatures for Northern Nevada. The air quality should be good as long as there isn't any wildfire smoke, right? Well, not necessarily. Let me explain.  Summer is the season of ozone (O 3 ). There is both stratospheric and ground level O 3 . The stratospheric ozone protects us from the Sun's harmful ultraviolet radiation. Ground level ozone is an air pollutant that harms humans and the environment especially during hot and sunny summer afternoons.  Ground level O 3  is created by the chemical reactions between volatile organic compounds (VOCs) and oxides of Nitrogen (NO x ) in the presence of sunlight. NOx and VOCs, also ozone precursors, come from motor vehicles, industrial processes, power generation, and consumer products among many other things including wildfire smoke. Urban and suburban areas will have higher levels of ozone than

Hot temperatures are returning to the Sierra and western Nevada this week ( forecast details ). Although some new record maximum temperatures may be hit this week, we are largely past the climatologically "hottest" part of the year . We typically see our hottest temperatures during July where the city of Reno can easily surpass 100 degrees for multiple days in a row. Although this past July was an exception to that rule since we had a significant monsoon push with thunderstorms for much of the month. Here are a few snapshots at the forecast maximum temperatures we are expecting for early this next week.  So what? It is going to be in the 90s and near 100 degrees out in central Nevada, no big deal right? Well it can be a big deal for those who spend their days working outside, especially for fire suppression personnel out on many of the large ongoing fires in the region. Since we are looking at multiple days of these hot temperatures, it would be a good idea t