Stu

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
Oct 122014
 

If you know me or my blog, you know I watch Lake Powell. Most of my posts are about the water level increase expected each spring and early summer. But many boaters have reported weather problems at the lake that weren’t related to dust storms, thunderstorms or wind storms. Triple digit temperatures are a common occurrence on Lake Powell. The high temperatures can cause engine problems.

Waterskiing at Lake Powell

Waterskiing at Lake Powell

On of the intended benefits of fuel injection was to prevent vapor lock. The gut reaction of most “gear-heads” and marine mechanics is that a fuel injected engine can not suffer vapor lock. I’m now a believer that there is a mechanism for vapor lock in a marine engine.

Marine engines run in a tough environment. The stern drive motors are typically inside a small engine compartment with limited ventilation and exceptional noise insulation. It’s a great environment for containing heat. The lower unit of the stern drive takes up fresh water and pumps it to the engine and support systems. It’s a great way to cool a motor while it’s running. But when you shut down a boat’s engine, there isn’t a natural heat release path. You can run the engine compartment bilge blowers to provide air flow. But there is no radiator like in a car. In the Lake Powell’s summer temperatures, blowing 110 degree air over a 155 degree engine has little effect.

To protect the fuel, a fuel cooler is a part of the cooling system. The fuel cooler’s intent is prevention of fuel vaporization due to high engine compartment temperatures. The water comes in from the outdrive, flows through the power steering cooler, then the fuel cooler, before going to the engine’s thermostat housing. This doesn’t work after the engine is shutdown, either.

Over the last few years our boat driving habits at the lake have changed. We used to spend lots of time on the beach with brief runs for water-skiing or wake boarding, or sightseeing. Now, we tend to do longer runs with plenty of canyon exploring and trips to Rainbow Bridge with friends. This means we run our engine longer and the compartment and engine gets thoroughly hot. Here is a temperature profile of the engine during a summer weekend trip. I measured the temperature on the top of the thermostat housing lifting eye. So, it wasn’t in direct contact with the housing or engine.

Engine compartment temperature profile, July 18-19, 2014.

Engine compartment temperature profile, July 18-19, 2014.

The heat build up is fairly quick. Idling the engine after a run provides a fair amount of cooling. But after shutting down the engine, the cool-down is much slower. Opening the engine hatch provides a better cool down of the top of the engine. Shorter runs result in a much faster cool down. We had to open the hatch because the engine wouldn’t start; we hypothesized vapor lock. But the engine compartment temperature had cooled much at this point. Shouldn’t it have started?

There is a theory about some marine engines. The theory is that some of the engine cooling water flows backwards after engine shutdown. This takes very hot water out of the engine and back the way it came. The first stop on the way out is the fuel cooler.

My son and I tried to replicate the outcome. We took our boat on a long, roughly 40 mile round trip. We went straight back to our slip at Wahweap Marina and shut down the engine as quick as possible. We watched the temperature on top of the thermostat housing lifting eye, and the air temperature inside the fuel cooler box, just an inch or so away from the real heat exchanger.

Thermostat housing and fuel cooler temperature

We watched the fuel cooler temperature quickly move from 101.5 degrees F to 121F at 15 minutes, and hit a top temperature of 124F by 30 minutes. At 45 minutes, we thought the temperature had stabilized and attempted to start the engine. It turned over, but didn’t start. We took a video the fuel being injected at the throttle body when cool, and again when it failed to start.


The fuel spray in the hot video is quite different with spurts, drips and gaps in the flow. The cool fuel spray is well atomized. What a difference!

On other trips, I tried to measure the temperature of the cooling hose that allows back-flow to the fuel cooler. Since the data logger I used had a self-protection turn off at 140F degrees, it only produced a few minutes of data as the temperatures climbed above 140F. Back-flow was the likely issue.

Mercruiser is the manufacturer of my engine. They have provided a tech bulletin about this vapor locking issue on their V-8 engines.

Mercruiser Vapor Lock Tech Bulletin

One of the solutions Mercruiser gives is to insert a check valve in the cooling system to prevent back-flow. I opted for this option. I installed the check valve in the cooling line between the fuel cooler and the thermostat housing. When I removed the existing hose, I found that it was mostly empty. To me, this validated the back flow problem as an issue. The top part of the engine coolant drained out via the fuel cooler. With the included instructions, the valve was remarkably easy to install. An experienced mechanic could do it in probably five minutes. I invested 45 minutes. Here’s a picture of the installed valve.

Cooling line check valve installed. Blue with yellow in the lower right.

Cooling line check valve installed. Blue with yellow in the lower right.

To test the repair, we did a high-speed run to Rainbow Bridge. When we shut down the engine, I watched the fuel cooler temperature. At 15 minutes, the temperature had dropped by 0.3 degrees. In other trips since then, it has occasionally increased, but never above 103F.

Every pump has a low pressure intake, and high pressure discharge. The fuel pump takes it suction on the outlet of the fuel cooler. The pump’s suction can vaporize the heated fuel, even if it is below boiling point. I wanted to record this some place because many boaters at Lake Powell to get hit by this phenomena.

 Posted by at 6:35 pm
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