Hold the Hype, Please

For the past few days, the models have been very inconsistent with one another, and from run-to-run (meaning the morning version of a model disagrees with the same model's afternoon version which disagrees with the night version and so on). The problem storm is a nor'easter that is expected to develop over the Gulf of Mexico before storming northward on Monday. Some models had been pushing the storm off the east coast, while others bring it further inland. As is always the case with these types of storms, the track is everything.

The evening models last night (Thursday) finally showed some agreement with a more inland track. This had some major implications on the meteorological community: the hype machine was put into full throttle. To understand this, and the forecasts that are gushing out, the public needs to glimpse into the mind of a meteorologist for a moment.

Most of us love storms...it is just part of our nature. Active weather is exciting. Unseasonable weather gets our adrenaline pumping. Average temperatures and sunny weather are, dare I say, boring. So when there is a big storm on the horizon, there is always a temptation to sensationalize it and force our predictions into more of what we want to happen and less what the models actually say will happen. This is called 'wishcasting'.

It is difficult not to wishcast, and it is something I struggled with a lot during the early days of Grotonweather. I easily got caught up in hype and would force situations to what I wanted to happen. I would latch onto little parts of the model that supported my desire, and ignore larger parts that would indicate I was about to make a bad forecast.

So when the models came into some semblance of agreement last night, the floodgates were opened. Many now felt justified in making big predictions-- after all, the models are all agreeing now!!

Hold the hype, please.

This is a nor'easter we are talking about, a proverbial thorn in the side of meteorologists for as long as they have been predicting weather in the Northeast. The models three days out for a nor'easter often do not capture the details that make or break the storm. Sometimes even the models a day out are no good. Consistency is the key. Just because the models yesterday evening agreed does not mean they will not disagree again this morning, afternoon or evening. It would be wise to see a few more runs of consistency before calling for a monster storm.

But now, to the wishcasting.

As I said above, meteorologists love active, out-of-season weather. What is more out of season than a heavy snowstorm in late April? And that is exactly what some meteorologists are calling for over parts of the region. However, given the current models, I feel such a forecast is uncalled for. Could it happen? Sure- history shows it can. I just do not think anyone is justified in making that call yet.

The first problem is the "540 thickness line". Meteorological jargon for sure, but let me explain. One of the (many) equations we have to learn in school related the average temperature of the atmosphere above a given point to the pressure at certain levels in the atmosphere. A warmer atmosphere will cause higher pressures, and thus a "thicker" atmosphere.

There are certain rules of thumb for how "thick" an air column above a point can be before the air is too warm for snow. One of those rules is the 540 line. To keep things simple, it suffices to know that values below 540 are favorable for snow and values above 540 are going to be rain. This rule has a catch though: it works best in the dead of winter. In late fall and early spring, values at or just below 540 probably are going to be rain, or perhaps a rain/snow mix at best. I like to see values closer to 534 before I get excited about snow.

Let us now look at Monday morning at 8am, the time that many meteorologists are posting images of the models for. Surface temperatures will be coldest at this time, with daytime heating kicking in for the afternoon Monday.

Major snow storm? The models don't think so.

As you can see, these three major models all indicate little, if any, snow confined to the far western fringes of the storm. Additionally, temperatures have been unseasonably warm all winter and spring. The ground, therefore, is also unseasonably warm. Late April storms of the past (2007 and 1993 for example) have come following very snowy years where the ground was likely cooler than normal. I have a hard time believing snow would accumulate very easily except perhaps over the highest elevations unless it got very cold (surface temperatures in the 20s).

Models try to directly guess the precipitation type and snowfall amounts, and some will undoubtedly point to those model outputs as their justification. (The NAM model, for example, has 6" of snow in Ithaca on Monday). Those model predictions are basically made by taking the model predictions, putting them through more equations and conditions, and then trying to make a new prediction. They can be useful, but the more processed the model data is, the greater the opportunity for error. The precipitation type and snowfall amounts, especially from the NAM model, I have found to be rather unreliable this spring. A few weeks ago, this same model insisted on bringing Ithaca another storm of 6-12". It rained.

In conclusion, this is what I want the public to take away from this. We don't know what will happen yet. Confidence is low and this system needs to be watched. While I enjoy the loyalty my patrons have to Grotonweather, I encourage them to look at other forecasts, too. I have been wrong before and will be again in the future.

What I want other meteorologists to take from this is as follows: we, as a meteorological community, need to focus more on uncertainty and communicating that in our forecasts. We need to cut the hype and sensationalizing every large storm. There are times when we NEED to really play up a storm- like last weekend's tornado outbreak. There was a lot of justified hype last weekend and it saved lives. This weekend's hype is not justified. Where do we draw that line? It is impossible to say for sure. But I can say it needs to be drawn better than it currently is, or when it does matter, people are not going to listen.

Winter Over? Not so fast...

Update: 1:30pm
I just wanted to add a comment here. I have been reached out to by multiple members of the Channel9 Storm Team to discuss this all further. Additionally, they posted a second post on their Facebook page to give greater clarification to their statement. This is why I started my blog post below praising the Storm Team meteorologists and expressing my great respect for them!

I've considered taking this blog down all together based on the conversations I've had with the Storm Team. I've decided to leave it up, however, because I do feel that public interpretation of forecasts is a crucial topic. I think this whole situation can shed some light on the topic for meteorologists and the public alike. Forecasting is difficult enough. Expressing the forecast to the public is another thing entirely.

Original Post:
Every once in a while, I come across a forecast that, quite honestly, makes my skin crawl. I try not to be judgmental about them- I've made plenty of bone-headed forecasts myself. At the same time though, sometimes something just needs to be said.

Let me preface my forthcoming rant with the following: I have a great deal of respect for the meteorologists at News Channel 9. I have met a number of them and they are great people. Their forecasts are typically very good and they are extremely intelligent. They do a great job.

Just not this time. This isn't meant to be an attack on them in any way, but the record needs to be set straight. It is February 17th. Historically, we could see significant snow well into April. (see April 16-17, 2007 for example). I cannot fathom how anyone can declare winter over at this stage, but that is what Channel 9 did:

First, let's look at the graphic that they are using to declare winter over. It is a probability map put out by the Climate Prediction Center for March, April and May. Areas in orange have a chance of seeing above normal temperatures, while areas in blue may see cooler than normal temperatures. Areas in white have an equal probability of seeing either cold, warm or normal temperatures. Let's zoom in and take a closer look at the Northeast:

Now, there are three possibilities for what can actually happen. We can be above average, below average, or right at normal. So in the white, "equal chance" areas, the probabilities of each of those three outcomes is about 33%. Each shade of orange/blue represents a greater chance of seeing warmer/colder temperatures. The Climate Prediction Center labels each shade with a percent value.  I have marked the 40% line, as it was a bit hard to see. Areas inside that 40% line, that is in the darker orange shade, have a 40% or greater chance of seeing above normal temperatures. The lighter orange shade, which includes Central New York, is predicted to have a 33-40% chance of seeing above normal temperatures. Given that the 33% line is very close to us, it can be assumed that it is more like a 33-35% chance.

That means we have about a 2% chance more than normal of seeing above normal temperatures.

Since the chances of a warm March, April and May are up by about 2%, and probabilities must add up to 100%, we can assume that the probabilities of a colder than normal March, April and May are running at about 31% and a normal period at 33%. Let's look at this forecast in another way:

Honestly, can you see much of a difference? Yes, we have a higher chance of above normal temperatures than anything else. But that increased chance is such a minor increase. If these were medical test results, would we want our doctors declaring definitely that the test was conclusive one way or another with a 35-33-31 distribution? I think not.

The other thing to consider is how accurate these probability forecasts are in the first place. The following as a graphic the Climate Prediction Center publishes along with their seasonal forecasts. It looks confusing, but I will explain it:

First, some background. There are numerous ways to calculate forecast accuracy. The Heidke Skill Score (HSS) is just one of those ways. A HSS of 100 means the forecast was perfect. A HSS of -50 is the worst possible forecast, and a HSS of 0 means the forecast was as good as a random guess.

We are looking at the red lines, which are labeled 'non-CL'. These 'non-CL' lines are the skill of forecasts where either colder than normal or warmer than normal forecasts are made. The year-to-year changes between these red lines are huge. You will notice a horizontal red line at 20. This is the average HSS for non-CL predictions from 1995-2008. The score is 20. Remember, a perfect forecast is 100 and a random guess is 0. A 20 is an extremely poor score and shows just how difficult it is to predict temperatures for the next three months.

Putting these two things together, we have a very slim chance of warmer weather based on a forecast that is much closer to a random guess than a perfect forecast.

With this knowledge, can you see why this upsets me? Meteorologists have an unspoken contract with the public to give accurate, informative forecasts. We have to do this to build trust between the meteorologist and the public. Why? Because when a tornado is bearing down on your neighborhood, or a major snow storm is on the way, or anything else that threatens lives and property, we need people to listen to us. Way too often, meteorologists, particularly in the media, betray this trust with garbage statements like this.

It needs to stop.

Now, I commented on that Facebook post and the response I got was "our forecasts are based on more than just what we are showing here- this graphic just happens to sum things up nicely." My argument is that 1) the graphic really shows nothing, as I explained previously and 2) there is no expression of uncertainty or these other factors. All that is said is 'winter is over.' I'm not against long-range forecasting. I am against long-range forecasts that don't express the inherent extreme uncertainty that they contain. And this is one of the worst offenders I've seen.

Might they end up being right? Sure. They might. If they are, was it skill or luck? I'll let you be the judge.

Arctic Outbreak?

We all knew it was probably only a matter of time before the weather finally turned more winter like. We got a taste of winter yesterday with some lake effect snow, strong winds, and temperatures in the 20s. While we have been warm lately, 500 miles to the north has been frigid. The chill yesterday and, to some extent, today, is just a small piece of that cold pool.

A much bigger piece will be breaking off next week. It will easily be the coldest air so far this season, with highs Tuesday and probably Wednesday staying in the teens. There will be wind. There will be snow. But will this be an 'arctic outbreak'?

There is no set definition for an arctic outbreak, so the use of the term is up to the discretion of the forecaster. It seems to me, however, that 'arctic outbreak' should be a term reserved for record setting or dangerous cold. It is a strong term that grabs people's attention. I do not think it should be overused.

Does the combination of high temperatures in the teens, gusty winds and lake effect snow meet these qualifications?  I am honestly on the fence.

On the one hand, it seems to me that highs in the teens are not all that impressive, given our climatology and the time of the year. Some lake effect snow and wind? That is just normal winter weather here.

Yet, on the other hand, this has not been a typical winter. We have only one high temperature under 30º (on the 24th...the high yesterday was actually 40, albeit that was at midnight). Snow has been scarce to non-existent. Being suddenly thrust into mid-winter weather may catch some off guard and create dangerous conditions.

In the end though, I think I would hesitate to use the words 'arctic outbreak' in my forecasts for the coming cold snap. I believe that the public should be aware that the pattern is changing and, at least for a few days, winter will be here in full.

But I do not want to sensationalize things and blow them out of proportion. This event, after all, is still nearly a week away. I've seen many extreme temperature events forecast this far out, only to have the models gradually and consistently modify temperatures back towards more normal temperatures.

I want to hear what you think though. Join the discussion and post what your definition of an arctic outbreak would be on Facebook by clicking here.

2/24 PM Forecast Discussion

My apologies for having to post this here. The SUNY Oswego campus network has somehow decided to block all Grotonweather.com traffic from its network. I have managed to update most of the forecast as normal, but things such as the confidence forecast and uploading snow maps are impossible. Hopefully this will be fixed soon....in the mean time, we have a snow storm on our hands!

Forecast Discussion
A rapidly strengthening storm system over Arkansas will lift north and east, crossing across Pennsylvania tomorrow morning. The models are more or less in agreement with one another now, and they all keep the warm air and rain to the south. Despite this, I am still a tiny bit weary of the possibility of rain for Tompkins and southern Cortland County, as the rain/snow line will only be 30-50 miles to the south. I do have enough confidence to go with all snow now though. As I said this morning, since this storm is probably going to end up all snow, we are going to get it good. Below the discussion is the snow map I made for this storm. Most of the Grotonweather.com area is in the 7-14" range. Honestly though, I would not be at all surprised to see 16" or even 18" somewhere in that pink area. The snow will move in after midnight tonight and really become heavy for the morning hours tomorrow. By afternoon, the snow should begin to taper off. However, the winds will be on the increase, blowing all that fresh snow around. Significant blowing and drifting is likely tomorrow. I would likely be going into SNOW ALERT MODE if I had access to my files. Saturday and Sunday will each feature a shot at a few flurries, but nothing significant. Another storm will be in the works for Monday, but this one should remain all rain with the low tracking well to our west.


Storm total snowfall through Friday evening.

The Hype Machine

My good friend, classmate and colleague Evan Duffey posted a wonderful piece on Syracuse.com this morning. He has given me permission to repost it here. There are a lot of excellent points he makes about how big storms get blown way out of proportion through hear-say and media hype. Take a look:

Storm under-performs, public and media hype make it worse

For those of you wondering why you children's classes were canceled, or what happened to the 18"+ of snow you were expecting because your neighbors told you it would happen, I have your answer. The storm grew to massive size and intensity - in a special place I call overexcited media and populace. The storm, while no pushover, is not that epic, and should never have been treated as so.

In talking to fellow Meteorologist and Syracuse.com blogger Andrew Montreuil, he agrees he is upset at how this storm got hyped up.

While the storm will probably leave a decent impact on the area, talk of 18", 2 feet, etc. have been floating around either word of mouth or the internet. My max total event given during the entire even was 14".

Which brings me to a point I would like to bring up. A MAX snowfall accumulation is not what we expect, it's more then what we expect. When a meteorologist puts up a snowfall range, even I put a little extra on that top number just in case the unexpected occurs. Sadly the public takes this number as what they are going to get. For all of you interested in weather, try to remember this when reading forecasts and discussions.

Now to the meat - why did this storm under-perform even Meteorologists predictions for a storm? I hinted at the reason in a comment I made a few days ago, in my first post about the storm. I said "I think the upper limits of snowfall are possible only if warm, dry air doesn't work its way in too far North." This is pretty much what happened.

Radar overnight revealed a large dry slot was working into the storm. Dry-slots are almost always destructive to storms, taking away some of their thermodynamic strength, and obviously precipitation is hard pressed to be found in an area called a dry slot.

Blogger Drew Montreuil was involved in a Q&A session recently, and one of them really brings to light a lot about the forecast and expectations. Here is the quote:

...just in my day today I have overhead people talking about how we are supposed to get 2 feet of snow and such. These are over exaggerations. Often times, forecasts for big storms seem to take a life of their own. People mishear or misread things and, like a massive game of telephone, things get blown out of proportion. Another common mistake I see all the time is people assuming the high end of a snow prediction will be what happens. If there is a forecast for 6-12", but only 5" falls....it really is a decent forecast. But the hype before hand makes it seem like a bust.

To answer the question directly...I could see this "busting" slightly, yes. There are some indications drier air may work in quicker than what was earlier thought. This could bring the snow to an end a bit quicker, and keep us more in the 4-7" range instead of 6-10". Its a developing situation, and one can never be too sure they have the forecast nailed until the event actually happens...

Hopefully your day isn't too upset by the hype and over forecast of this winter storm, and please don't blame meteorologists. We aren't all that wrong.

Just how low did it go?

Original post appeared on Syracuse.com on 1/26/11; posted by Drew Montreuil. This version is edited.

You certainly do not need a meteorologist to tell you that the cold was bone-chilling Monday morning. However, you might be interested to know how cold it actually got across Central New York.

Click the map for a bigger view!

I put together a map of reported low temperatures from around Central New York. Most of these low temperatures were reported to the National Weather Service through co-op spotters. Some of the other readings were recorded on personal weather stations that upload data onto The Weather Underground.

As you can see, the temperatures can vary greatly over a short distance depending on a number of factors, including elevation, proximity to water and urban vs rural settings. A great example of this is Groton's reported -8º. This temperature was taken at a high elevation somewhat near the Elementary School. On cold nights, the coldest air settles in the valleys. Therefore, I would not be surprised if someone sees the map and thinks: "But I saw the bank thermometer Monday morning say -15º!" Down in the valley, it probably did drop below -10º. If anyone does have a lower reading from downtown Groton, I would be very interested in it, so please leave a comment!

For comparison to previous years, we have to look at Syracuse, since climate data from the NWS is only available for Syracuse and Binghamton. You may be interested to know that the -13º was the lowest temperature in the past few years. The lowest temperatures for the past few years in Syracuse are as follows:

• 2010: -9º
  
• 2009: -2º
  
• 2008: -4º
  
• 2007: -9º
  

Data from before 2007 was not available on the National Weather Service's Climate site for Syracuse. I can, however, tell you that the -13º is no where near the record low for Syracuse since observations began at the airport in 1971. That record belongs to February 1979, when it was -26º.

Winter's Fury Unleashed

As posted by Drew Montreuil on Syracuse.com, 1/21/11

Old Man Winter sure is angry these days, and we will not be escaping his wrath over the next week or so. The first fits of his anger are already being felt across much of the northern half of the country. Yet another Nor'easter is striking parts of New England. This storm brought us 3-6" of snow overnight, but parts of Maine will see over a foot.

In the Midwest, the National Weather Service (NWS) issued an 'Extreme Cold Warning' for parts of Minnesota last night. The Extreme Cold Warning is a new warning the NWS is trying out for temperatures lower than -40º. The warning surely verified, as temperatures this morning in International Falls, Minnesota got down to a mind-numbing -46º. Even Rochester, Minnesota, in the southern part of the state, dropped to -20º.

Some of the cold is on the way for us, but Old Man Winter has another shot to throw at us first: another bout of heavy lake effect snow. Schools across northern Cayuga, northern Onondaga and Oswego counties are dismissing early in anticipation of the lake effect blitz.

A huge contributor to heavy lake effect snow in a set-up like today's is whether or not moisture from the Upper Great Lakes is able to feed the Lake Ontario band. Observations from Canada this morning are indicating that the connection is being made, which only will increase the chances of heavy snow.

The lake effect will start up this afternoon and last into tomorrow morning before only gradually weakening and moving northward tomorrow. Some areas across Oswego, Oneida and northern Onondaga counties could see upwards of 2 feet by late tomorrow morning.

If that was not bad enough, the cold temperatures and winds will bring wind chills down to potentially dangerous levels late this afternoon and tonight. Even those not impacted by the lake effect will want to make sure they are properly bundled up against the cold.

This is all just the beginning though, and the next assault from Winter's War comes in Sunday and Monday. The bitter cold air mass that was over Minnesota this morning will work its way over us later this weekend.

High temperatures Sunday and Monday will struggle to reach 10º, and Sunday night will be the coldest night we have seen in a few years. Many areas across Central New York will see the mercury drop to -10º, and some of the outlying areas may even see -20º.

And now, could a grand finale to Old Man Winter's assault be in the works? The latest long range weather models are showing hints of another coastal storm in the works for the middle of next week. If the current model projections hold true, Central New York could be looking at its biggest widespread snow of the season so far. While it is way too early to tell whether or not that will come to pass, it will need to be watched as we head into next week.

On the bright side...at least its not -46º!