Saturday, January 12, 2013

Inversion!

When we got back from Alaska after Xmas, northern and western Nevada was locked into a classic mid-winter high-pressure system, with a surface temperature inversion creating below average low temperatures on the valley floors (and higher temperatures in the mountains and at local ski resorts, something we did not actually check out this time). Classic Great Basin inversions with severe Pogonip events in the past have had people skiing in shirt sleeves in essentially spring skiing conditions (slushy snow) on Mt. Rose, while temperatures in the valley were -20°F or lower.

In fact, because of the Chinook that came in while we were up north, temps in Nevada were considerably colder than they were in Alaska. Reno was running lows of 10 to 16°F and highs of 30 to 33°F while Anchorage ran lows of 21 to 33°F and highs of 30 to 43°F. Our destination location, which we drove to on I-80 on January 5th (photos below), was having lows of -10 to -16°F and highs of 17 to 22°F.

Looking northeast along I-80 and the Fortymile Desert.
Steam from the geothermal plant at Brady's Hot Springs is rising straight into the air, one hallmark of high pressure and inversion.

The low hills of the Hot Springs Mountains fade into a smoggy haze. Wave-cut terraces of Lake Lahontan are enhanced by the thin snow cover.
Approaching the geothermal plant at Brady's Hot Springs, AKA Nightingale Hot Springs (see location at the end of the post).
A closer view of the steam from the geothermal plant at Brady's Hot Springs, which is mostly used to roast or dry onions.
By the way, although these hot springs are among the hottest in Nevada, at 83 to 98°C (181 to 209°F), they are entirely private, and can't be accessed by the likes of you or me. The Nightingale Hot Springs Exit provides access to the geothermal plant and a nearby fossil collecting area.

Looking northeast down I-80 and the Fortymile Desert
toward the West Humboldt Range.
The Humboldt Range is about 6 miles distant on the far right of the photo, beyond a dark, gently sloping hill, and is about 34 miles distant looking straight down the highway.

Looking south toward the east edge of the Hot Springs Mountains on the right, and at the hazy, fading Stillwater Range beyond the Carson Sink, center and left.
Tufa mounds in the Fortymile Desert on a Lahontan shoreline or terrace in the foreground; the West Humboldt Range 9 miles away in the left middle ground;
the hazy Stillwater Range in the far distance about 35+ miles (58+ km) away.
Location of the tufa mounds, from the USGS TNM 2.0 Viewer.
The hazy day didn't make for optimal photos: snow on the ground was bright white, the mountains in the distance were hazy white, and everything blended together. Finally, approaching our northern Nevada destination, the closer mountains offered bits of photogenic opportunities.

Blue Mountain.
I'll have to update my song about Blue Mountain, as it obviously becomes covered with snow in winter time!


Winnemucca Mountain.


After a few days, the high pressure and accompanying inversion dispersed, and light to moderate snowfall came into the area. And now, the cold valley temperatures are back: it was -15°F this morning at the airport, though only -4 or so at our banana belt location. As per the National Weather Service, "LOWS AT NIGHT WILL GENERALLY RANGE FROM 5 TO 15 BELOW ZERO WITH DAYTIME HIGHS OF 10 TO 20 DEGREES" into the forseeable future (link to this statement is probably not a permalink).

10 comments:

Lockwood said...

We're in the same situation here- got down to 21F last night, didn't break 32F today. We're not in a true inversion here... yet. It gets colder with elevation. But warmer air aloft is expected to come in next week, but not vigorously enough to scour cold air out of the valley. That can get pretty ugly (though not as bad as Medford/Rogue River Valley area), since smoke and exhaust gets trapped on the valley floor.

And yes, freezing fog and clear sunny is forecast for the next week. I'm spoiled, and don't like it this cold.

Silver Fox said...

I'm not really sure if we're in an inversion right now (though we were a week ago). It's easier to tell in a closed basin or valley like the one Reno sits in (at least for me) -- although I'm sure I could find the temperature by altitude on some site.

Where did I see that, anyway?

Lockwood said...

Have you used Wundermap? I love it. Use your sense though. Some of the linked weather stations are clearly messed up. For example, the rain gague at the Lebanon (OR) Airport apparently *starts* at 37 inches. http://www.wunderground.com/wundermap/

Silver Fox said...

That looks like a useful map, will have to try it out.

I did find this site for winds and temps aloft, but it looks like forecast only, for pilots, not like actual temps aloft as recorded (if they are recorded routinely).

Silver Fox said...

I can use the Wundermap to see inversions when they show temperatures in the valleys and in the mountains (aslo this map by clicking on individual stations.

There is currently an inversion in our area, with -15, -10F in the valleys (4300+/- feet elevation) and 0F in higher places (5000 to 6500 feet elevation). And we have a strong ice fog. Forecast discussion at NWS: "SKIES TO
CLEAR AGAIN SUNDAY NIGHT WITH BITTER COLD TEMPERATURES...WITH -10
TO -20 DEGREES COMMON IN MOST VALLEY LOCATIONS. MONDAY HIGH TEMPS
WILL STRUGGLE TO GET ABOVE 15 TO 20 DEGREES AS SNOW COVER AND A
STRENGTHENING LOW LEVEL INVERSION SET UP OVER THE AREA."

Hollis said...

Same here in Laramie. But I have to say -- the bitter cold is a nice alternative to Laramie wind!

Silver Fox said...

Ha! The famous Wyoming wind! Yeah, for once it isn't windy here, either.

Silver Fox said...

Woh! Terrible formatting using embedded comments!

Anonymous said...

Love the pictures of Blue Mountain!! beautiful!

Silver Fox said...

Thanks!