Tag Archives: weather

What The Heck Is A Diurnal?

With Paso Robles As Example

A diurnal sounds like a … uh, uh uh, easy guys, this isn’t toilet humor (pun intended). Actually, diurnal has more than one meaning and we’re not dealing with a daily journal.Partial Earth

No, what we will talk about is the diurnal (meteorologically speaking) that means the difference between day and night pertaining to weather temperatures. And in Paso Robles, on the California Central Coast, we have a doozy.

Summers offer big diurnal

In its most basic description, the diurnal is a spread of temperatures relating the highest in one day to the lowest of that same day or within the next 24 hours. For instance, one of the first summers I had here in Paso, we had a high of 106 and a low of 44. That differential was 62 degrees – an amazing temperature swing for 24 hours. And in actuality, it wasn’t even 24 hours as the high was around 4:00 p.m. and the low was about 5:00 a.m. In roughly half a day, the diurnal was 62 degrees.

Although this anecdotal example is a bit on the extreme, this huge change isn’t that unusual in Paso Robles, especially during the summer month cycle and is an interesting aspect to the area. In fact, August has highs averaging in the low to mid 90s with lows in the low to mid 50s. June, July, September and October also have wide-ranging diurnals. 50 degree disparity in highs and lows is common fare in summer and early fall.

Desert vs Ocean

Without going into another entire story on temperatures in Paso, the area lies at the backside of the Coastal Range and typical of many regions in California, the temperatures soar in the late morning through mid afternoons. Sea breezes begin blowing in from the Pacific Ocean, working their way through the mountain passes and dramatically cooling the air – thus, large varying temperatures from night to day.

Ranches and orchards once dotted the landscape as much as vineyards do now.

A large diurnal allowed for ranches and orchards, which once dotted the Paso Robles landscape as much as vineyards do now.

A slight offshore keeping the marine layer away with warm air aloft during the day and a sun beating down, allows temperatures to climb quickly up. When the late afternoon winds bring in the much cooler air: voila! You have a large diurnal. It should be noted that humid regions and/or areas with bodies of water tend to have a low diurnal. When thinking about moderate diurnals, think Great Lakes region along with the Eastern Seaboard, Gulf Coast and the immediate coastal areas of the Pacific Northwest. They see little change from day to night in temperature swings.

Those that live in the desert might know about the large temperature variation or diurnal. The Great Basin (Nevada) has normally huge divergences between high and lows in one day. If you look up wide swings in diurnal temperatures, you will inevitably hear about the Upper Plains like the Dakotas also having tremendous climatic variances – due in part to not having any large body of water to moderate the temperature. The continental landlocked plains of the Central Asian Steppe region also has severe temperature fluctuations due to lack of any major body of water. The record diurnal at 100 degrees is held by the small town of Browning, in northwestern Montana (source: National Park Service).

Mongolia

The Mongolian highlands or Steppe region is one of the areas of the world where the diurnal is wide ranging.

A day in Paso

Breaking the diurnal down inside a day, the greatest change is normally from late afternoon before the sun is low in the sky until just after sunset. Normally here in Paso, it might be 90 in summer on a typical late afternoon around 6:00 p.m. and by 9:00 p.m. it could be 65, possibly changing more than 10 degrees in one hour. By the way, several years ago, shortly after leaving a winery on a blistering hot August day, I looked up on the temperature inside the car and it read 110 degrees outside … and it was 5:30 p.m. And still the lows were in the 50s.

Paso Robles is generally a dry region and the only reason it isn’t a desert more so like the Central Valley – such as Bakersfield (100 miles east) where day time Summer temperatures don’t drop as severely in the evenings – is the effects of the Coastal Range; plus, Paso is only 20 miles from the ocean and the water temperatures blow in to keep it cooler.

Carrizo Plain

The lands just southeast of Paso Robles called the Carrizo Plain has quite a divergence between high and lows called a diurnal.

Soon I will be talking about how that diurnal directly affects Paso Robles and its grape vines. Hopefully this didn’t confuse you and I didn’t confuse myself – it has been done. Daily diurnal cycles are interesting characteristics of weather and your daily life, so the next time someone asks you about diurnals, now you know. And no, it doesn’t have anything to do with strange restrooms … keep it clean.  😉

Additional source: Idaho State University, Wunderground.com, State of California

Salootie Patootie,

Daryle W. Hier

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WineBarrelBizCard-background

http://pasowinebarrels.com/

 

Terroir?

If you happen to be associated in any way with the wine industry, you probably have come in contact with the word ‘terroir’.  Generally, I knew the word and its basic understanding … or so I thought.

The large rolling hills on the Croatian peninsula of Istria in the Northern Adriatic Sea, offer a unique terroir for wine making.

In normal terms, the word as I knew it stood for a type of geography and lay of the land, so to speak.  I looked the word up and although I was right in the simplest sense, the word means much more than I realized.  Merriam Webster calls it a ‘taste of the earth’.  Simply stated, that’s about right.  However, what does it really mean?

Well, you’re not going to get very many folks agreeing on the exact meaning but we’ll give it a try and maybe in the end, you’ll be a little wiser when you describe to your friends what it means.  By the way, its origin is French and it’s pronounced ‘tear wahr’ as in going on a ‘tear’ and armies going to ‘war’.

Any in case, the word has gone through a transformation of sorts.  Before the last decade or so, the word was given to mean more about wines or any beverage (or food for that matter) that had an earthy tone or taste to it.  This could be good or bad depending on exactly what was being described. Recently though, it now pertains more to a descriptive nature regarding a region, terrain, weather or soil conditions and types.

Descriptions

For instance, a terroir’s region or terrain might be rocky, or high in elevation as compared with another terroir which may be in a valley with much fauna.  A terroir’s weather could be hot and dry or cool and damp.  If a ground composition is a sandy terroir, that would be in comparison to a clay-like terroir.

Think of a terroir as the filter for what a vine works through.  A terroir’s soil along with the temperature and terrain can affect a wine grape and make it taste decidedly different than a same grape in an entirely different environment … or more accurately, a terroir.

Note that I’m no expert – just someone who has thoroughly researched wine barrels and with that exercise combined with being in the middle of wine country has brought many of these descriptions dealing with terroir, to the forefront.

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A mile up elevation-wise in the far northern reaches of Argentina, lies the Calchaquí Valley with a particular climate that helps to produce great wines from its distinctive terroir.

So you see it’s a combination of factors that give each terroir its uniqueness or character.

The precise and distinctive locality of a region including the topography and weather of a place differentiating from other places, producing a certain quality and personality, if you will – is in a word: terroir.

Hopefully that didn’t confuse you, but in fact, now gives you a leg up on family, friends and cohorts.

We often use the term here in Paso Robles, because certainly we have a distinctive terroir what with a vibrant soil and inimitable terrain combined with a huge diurnal (the difference between high and low temps in a day – we’ll have to have a quick dissertation soon on that term too).

All these differing attributes collective with changing environs and climate make for distinguishing features in terroirs all across the world.  And now you know the rest of the story … or most of it anyway.

Check out these books on terroirs of France and America:

Terroir: The Role of Geology, Climate, and Culture in the Making of French Wines

American Terroir: Savoring the Flavors of Our Woods, Waters, and Fields

Daryle W. Hier

http://pasowinebarrels.com/