Dan’s Wild Wild Science Journal

So while I am  looking intently at the model guidance for next week and the possible blizzard up the East Coast, Mother Nature decides not to wait!

It is looking very likely that a snow hurricane may develop in 48 hours over the Northeast! I bet my friends Harvey Leonard and Dick Albert in Boston are locked away looking at weather charts right now! Will it be too warm for a foot of snow?? Perhaps.If you are in Boston, listen to Harvey or Dick, they have forecasted a thousand of these!

Glad that forecast is not my problem today!!

High resolution Numerical Weather model for sunrise Friday. It indicates an intense low pressure near Boston. The black lines are isobars. The closer they are together, the faster the wind speed.

As for the possible blizzard early next week….

The models are still trending toward a weaker Southeast snow event…not sure I trust that yet!

GFS Model from NOAA for sunrise Tuesday. The red dashed line is the APPROXIMATE rain snow line. Image ctsy. Penn State Univ. Meteorology (Which hurts to say since I am an Okla Univ. Met. grad!)

The long range numerical weather prediction models continue to show wild run to run swings regarding the possible next winter storm to pound the Eastern USA. There is little doubt that something is coming, but the track and the amount of cold air is still very questionable.

Here is an example of the differences. The picture below is from the DGEX. It’s a long range model run this afternoon and the forecast you see is for Tuesday morning. It indicates a real heavy snowstorm developing and heading up the East Coast. This is the worst case scenario.

Long Range "DGEX" Model from Penn State Meteorology Dept. It is indicating a deepening blizzard early next week.

The Morning model run from the NOAA Global Forecast System (GFS) Model is much different than yesterday. It does not phase the northern branch of the jet stream and has a much weaker storm further south.

If you live in the Northeastern USA or Western Europe you are living through a very historic winter. Same for those living ,where I write this tonight, in Tulsa Oklahoma. Snow, snow and a lot more snow. Baltimore is buried under at least two feet tonight.

What’s causing it?

The Arctic Oscillation. (AO)

It also goes by other names. Older forecasters like myself prefer the NAO for North Atlantic Oscillation. Younger and brighter meteorologists prefer the Northern Annular Mode. Whatever you call it, the result is the same. This is what you can blame  for all the snow.

My friend Bob Henson at the National Centers for Atmospheric Research is an expert at making something complicated easy. If you don’t  believe me, read his book the Rough Guide to Climate Change. Click the image below to see his explanation.

It won’t get your car dug out, or your power back on sooner, but you will at least know why you are freezing under the covers!

NASA has released this model of Earth’s weather from 9 days in last August. The model was run at a resolution of 7 km. This is a very high resolution for a global model. You can see a bigger picture of the model run HERE. It’s a stunning example of how well we can reproduce our atmosphere inside a computer!

The highest resolution weather model I look at on a daily basis for forecasting is the WRF model. (Weather Research and Forecast model). It runs in a window over North America and is not global. We get 4 runs per day at a resolution of 12km. The forecast goes out 84 hours.

So why not run them all at 7 km?  Better yet make it a resolution of 4 km! Wouldn’t that give a better forecast?

Yes it would. Up to a point. (see chaos theory if you want to know why at some point you get diminishing returns no matter what)

The problem with increasing the resolution means you have millions of extra cubes of data that you have to do the math for. This increases the run time of the model. A weather model used to predict the weather for the next 3 days is not much use if it takes a week to get the output!

You can imagine it this way. Put 20 layers of sugar cubes on top of a map of the united states. The computer has to keep track of the weather in each of these cubes and using complex equations, it moves weather between cubes.

Now do it again with cubes that are half the size. You will see that it takes far more than twice as many cubes. You also have to use a shorter step in time and this more than doubles the run time!

One of the major problems with forecasting with computers is this. You have to tell the model the weather before you run it. Think about this for a second. You have to tell the model the weather in EVERY one of those cubes.

The NOAA WRF model I look at daily has more than 20 layers up to over 20,000 meters! All of them 12 km wide.

We obviously cannot afford to send up a weather balloon every 12 km! If we did, air traffic would have to come to a stand still twice a day for about two hours!

21 different computer model runs forecasting the height of the 500 millibar surface.

We also do not have surface weather stations every 12 kilometers apart either! So the weather is estimated using various techniques based on the data we do have. It’s amazing how close we come on most days to initializing the model with a very close approximation of the real atmosphere!

The fact that nations share their data makes it possible. Even during the cold war, we shared weather data with the Russians!

Still, the “first guess” we give the models is not perfect and this is one reason why weather models beyond about 5-7 days are not very trustworthy. The longest range model used for forecasting on a daily basis is run out to 10 days.

One way around this problem is to run the model several times (with very slight changes to the first guess weather) and take an average forecast. This is called ensemble forecasting and the idea is that the consensus among the models is most likely to be correct.

Research shows this to be true and there has been some very promising research on forecasting hurricane tracks using ensemble methods.

Climate models due a very good job of reproducing past temperature changes. This is why scientists are so concerned about what they are forecasting over the next 100 years.

Models used by the IPCC have a resolution of around 100 km but they are run for hundreds of years back in the past or into the future. Ensemble forecasting is also used to a great degree.

How good are these models? The graphic on the right shows a comparison of the climate model run with the actual air temperature over the past 150 years. When you want to know just the average climate, you don’t need to have the high resolution.

We don’t need to know what time it starts raining on June 4th 2098. We DO want to know how much it rains that year in a given region! This is the difference between weather and climate models.

When you put in the increasing greenhouse gases, it tracks very closely with what has happened. This is one of the major ways we know that it’s the CO2 and NOT natural changes. (Someone needs to explain this to the former Alaska governor who obviously doesn’t know it.)

The lesson to take away here is that asking a meteorologist for a forecast beyond 7 days is a waste of time. I can sometimes give a general trend out to 10 days but beyond that is simply not reliable. If you want to know the approximate time it will clear or the rain will stop, then 36 hours is really pushing it in most cases.

An error of less than plus or minus 5 degrees F. on a 5 day forecast makes me happy. Less than three degrees is excellent.

I should have charged double!

(Note I changed the name of this post slightly after publishing it initially- I just liked the new name better!)

This past week has brought some serious flooding to California. This could not come at a worse time with so many hills and mountains denuded of ground cover by the Summer fires. No ground cover means nothing to hold the soaked soil in place, and it will take even less rain than normal to start the famous mud slide season.

Here in my part of the world, it’s almost as bad. Heavy rains have fallen for weeks here in the Southeast corner of North America. You should see the path from my driveway to the front door. The sidewalk of brick is under the mud.

Is it likely to continue?

YES

You can blame it on El Nino. The folks at NOAA who keep up with the temperatures of the Equatorial Pacific have updated forecasters with their latest data and model runs. It looks likely we will see a moderate El Nino this winter. For Geeks- you can get the NOAA powerpoint for forecasters here: enso_evolution-status-from NOAA CPC

El Nino is officially here when the surface water in an area of the Pacific, called the NINO 3.4 region, is warmer than normal by .5C for three months in a row. (see map and graphic above.)

This means more dust in Austrailia and even more drought. California and the Gulf Coast can expect a very wet and stormy Winter. It will likey be very mild across Western Canada.

Something to remember here. Every El Nino is a little different.

So far the rains here in the southeast seem to be a bit further North than is typical for El Nino. There is no way of knowing if that will continue into December, but if you live in the Southeast or California, prepare for a wet winter. Snow lovers in the Canadian Rockies may be in for a disappointing season.

Temperature Anomalies in the Pacific- Courtesy NOAA- Climate Prediction Center.

Numerical weather prediction models are all predicting the El Nino to continue and several are indicating a strong one. Most are indicating a moderate event. (see below)

Forecasts of El Nino this winter from several different model runs. (NOAA)

There are also some climate change aspects to this story. The warm waters produces by El Nino cause the planetary temperature to rise. The El Nino of 1998 was one of the strongest on record and made that year exceptionally warm. La Nina does just the opposite.

The global warming deniers on their junk science web sites (Political propaganda really), draw a line from the warm 1998 year, to the cool La Nina years and then scream global cooling. There is only one word for that.

Ignorance.

The truth of the matter is that the planet continues to warm, and all the real science, shows that the melt in Greenland and the Antarctic is accelerating. I will have more on that in the next post.