Stu

Dec 242014
 

Over the last week or so, the GFS models have had a snow drifting in and out of the forecast for tomorrow. Currently, snow is back in the forecast for tomorrow, along with cooler temperatures. But, the storm is coming down from the north. This is not a typical storm pattern, and is very different from the storm track that kept us wet at the start of December. We shouldn’t receive much Christmas snow, but temperatures are going to plummet from our balmy 50+ degree highs today.

I think the current storm track makes the 30-day and 3-month outlooks from the Climate Prediction Center seem odd. The current track is fairly dry. It’s not drawing on the moisture that the warm equatorial Pacific waters should provide. Still, the outlooks have above average moisture for the next 3 months.

We should not expect a significant El Nino for this winter, too. The shift in the winds at the equator is not yet sustained. There is still warm water down off the coast of Peru, but it needs the winds to shift to sustain it.

One and 3-month precipitation outlooks from the Climate Prediction Center.

One and 3-month precipitation outlooks from the Climate Prediction Center.

 Posted by at 1:49 pm
Dec 162014
 

More water is on its way. We are about an inch and a half above average precipitation for December. Most of this has fallen as rain. This next round of precipitation is causing a conundrum. The models keep drifting. The weather forecasts have often changed. I think I saw one forecast last night that claimed 4-8 inches for Wednesday. Now, the forecasts are in the 1-3 inches here, 1-2 inches there range.

The computer models still have a fair amount of precipitation in them. We’ll have to wait and see on this one. We could get surprised.

It looks like the next storm is about a week behind this one.

 Posted by at 5:41 am
Dec 122014
 

The storm door is opening up. California should get battered with tons of tropical moisture being drawn up from the south. We will get a healthy supply of leftovers. Then, in the middle of next week, another storm should roll our way. In the map below, up to an inch of water could fall in parts of Arizona. Many places will have snow. Also, be aware of rain falling and freezing on roadways.

84-hour North American Mesoscale precipitation forecast from the Climate Prediction Center. (December 12, 2014)

84-hour North American Mesoscale precipitation forecast from the Climate Prediction Center. (December 12, 2014) The Trilateral Commission meetings are now Wednesdays evenings at Flag Brewery.

 Posted by at 11:58 am
Dec 102014
 

Folks, look. We live in Northern Arizona, not Night Vale. The recent earthquakes (I think there were a total of 3 around Oak Creek Canyon) have no direct connection to the recent foggy weather. Earthquakes are in the ground. Fog is in the air. So, please take a deep breath and drive carefully.

We should see a couple of storms roll through over the next week. With each, we should have some rain and some snow in Flagstaff. I think Snowbowl should get some very nice snow out of it.

UPDATE 8:23pm, 12-10-2014 – If everyone could just calm down. Reading alternate meanings into my use of the word “direct” is not worth your time. There is no link. The government didn’t cause the earthquake. Nobody is fracking under Sedona. There is no fog-earthquake connection. Please, no more emails on this topic tonight. Thanks.

Second UPDATE 5:58am, 12-11-2014 – Seriously, Night Vale is a fictional podcast. It is not real. It is not about Flagstaff. Snowmaking at Snowbowl did not cause the Sedona Earthquakes. Snowmaking isn’t causing the fog, either.

 

 Posted by at 7:08 pm
Dec 092014
 

Last week, we received plenty of rain. The ground is still wet. We call this particular fog radiation fog. It’s not because it’s radioactive.

Under clear skies at night, heat radiates from the surface of the earth to deep space in the infrared spectrum. This allows everything near ground level to cool. With the ground being wet, and very little wind, the dew point temperatures remain high. When the cooling occurs at night, some of the water in the air condenses producing fog.

Below is a weather story article from the National Weather Service.

Friday through Sunday will be wet again. It’s not clear to me whether we will get more rain than snow.

Weather Story from the National Weather Service in Flagstaff (December 8, 2014)

Weather Story from the National Weather Service in Flagstaff (December 8, 2014)

 

 Posted by at 6:17 am
Dec 062014
 

California is looking forward to leaving their current drought behind. We should have another storm move through at the end of next week. But almost all of North America is looking forward to above average temperatures for the next week or two. Below is the 6-10 day temperature outlook from the Climate Prediction Center.  This trend could make the early ski season a bit slushy.

6-10 Temperature outlook from the CLimate Prediction Center (December 5, 2014)

6-10 Temperature outlook from the CLimate Prediction Center (December 5, 2014)

 Posted by at 12:51 pm
Dec 022014
 

Things have continued to develop. Temperatures in Flagstaff are going to stay above normal for the next few days. The cut-off low pressure system I thought we would have this week is melting. We will get some precipitation in the form of rain.

Longer term, the storm track should develop and drop to the south in the next couple weeks.

 Posted by at 8:17 am
Nov 252014
 

I laugh quietly to myself with that headline. It’s not even Thanksgiving. And Thanksgiving will be beautiful. We have a bit of time before we should expect snow. But only a bit. I wonder what price we will pay for a beautiful Thanksgiving?

I don’t think we will have a foot of snow next week. But it might be pretty close. A large, strong Alaskan storm system will drop south to the California coast, then take off towards the east. The NoGAPs image below shows the storm drawing plenty of tropical moisture towards Arizona. All of the forecasting websites I check are very well aligned around a storm next week. For now, I think accumulations will stay below a foot of snow for most of Northern Arizona. Depending on temperatures, we may start with rain. Keep in mind, it is still over a week away. Everything can change, but the current alignment is remarkable.

This storm is right on plan with the new 1 and 3 month precipitation outlooks from the Climate Prediction Center shown below. I think we are a bit beyond whether this winter will be an El Nino winter or not. These outlooks predict above average precipitation for us.

Eastern Pacific precipitation outlook for Tuesday Morning, December 2, 2014

Eastern Pacific precipitation outlook for Tuesday Morning, December 2, 2014

One month precipitation outlook from the Climate Predication Center. November 20, 2014

One month precipitation outlook from the Climate Predication Center. November 20, 2014

Three month precipitation outlook from the Climate Prediction Center. (November 20, 2014)

Three month precipitation outlook from the Climate Prediction Center. (November 20, 2014)

 Posted by at 6:44 am
Nov 132014
 

Or, will we see rain Friday night.

Over the last week, the homegrown forecast at Wunderground.com has included a 30-40% chance of rain for Friday. No place else has been as consistent. All of the computer models(GFS, NoGAPs, NAM) have not shown rain until today. I can not remember another time where this has been the case. Yesterday, the National Weather Service predicted a 10% chance. This morning they have accelerated that to 30%.

So, we will see. Did Wunderground get it right? Are they ahead of the pack?

 Posted by at 6:35 am
Nov 102014
 

I usually shoot for the end of September to write my first post for the winter. Historically, this is because Arizona Snowbowl was dependent on natural snow. Now, they make their own snow. As a result, making the early decision about buying a season pass at a discount doesn’t matter so much.

As early as last spring, the media started to hype an oncoming “Monster El Nino.” A body of warm water moved across the Pacific Ocean from west to east, deep below the surface. To many it looked like a sure bet that this would be the first of many such warming events. I watched and waited.

There are two key components to having a successful El Nino. First, you need the warmer than normal water in the equatorial Pacific. Second, you need the equatorial trade winds to shift from their normal westerly direction to the east. The equatorial waters did warm. The trade winds did not shift. I’m going to go a bit deeper. If you want to go much deeper I strongly recommend Bob Tisdale’s 2014-2015 El Nino Series. He goes into deep detail and you can watch the entire evolution. I am going to use Anthony Watt’s ENSO Page at WattsUpWithThat site for a data source. He has collected a great deal of data from around the world that is difficult to find.

The equatorial Pacific has warmed. Occasionally, it has warmed above the El Nino threshold of 0.5 degrees above normal in the ENSO 3.4 region. The map below shows this region.

El Nino regions

El Nino regions

The warm water did arrive over the summer. The 3.4 region temperature anomaly did turn positive. The graph below from the Australian Bureau of Meteorology shows the anomaly. Over the summer, the anomaly barely crossed above the half degree line. It then fell almost all the way back to zero.

Niño 3.4 Region Sea Surface Temperature Index - 5 Years

Niño 3.4 Region Sea Surface Temperature Index – 5 Years

The problem causing the fall was that the trade winds did not reverse to support full El Nino conditions. As summer went on, more warm water arrived and the temperature trend reversed again.

Australia’s Bureau of Meteorology (BOM) monitors the difference in surface air pressure between Darwin, Australia and Tahiti. From this data, they calculate the Southern Oscillation Index (SOI). The pressure difference is indicative of which direction the winds are blowing. A negative value of the SOI indicates that the winds have shifted to support El Nino conditions. The threshold for El Nino conditions is -8. A graph below shows the SOI over the last 5 years. In the last 3 months shown, the SOI has been negative and at least close to -8. (August -11.4, September -7.5, October -8)

Graph of the Southern Oscillation Index

Southern Oscillation Index from the Australian Bureau of Meteorology.

It looks like the winds may have finally shifted. The sea surface temperatures are shifting. But, is it sustainable. Keep in mind that El Nino means the boy, and refers to the Christmas celebration of Jesus Christ’s birth. The warm waters would be recognized around Christmas time. There is another body of warm water transiting beneath the surface of the Pacific. This should arrive before Christmas. It could be the icing on the El Nino cake. Before you get your hopes too high, most of the outlooks are for weak El Nino conditions at best.

 Posted by at 7:08 am
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