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.

What does an "Alert Mode" mean?

Every once in a while, grotonweather.com will go into "Alert Mode" for various weather phenomenon. Flooding, heavy snow and severe thunderstorms are the three most common prompters of an Alert Mode. But what exactly do I mean by this, and how do I determine when to go into Alert Mode. This post will hopefully help you understand this better.

The Alert Mode is reserved for special instances of exceptionally dangerous weather that will impact the lives of those in and around the Grotonweather.com forecast area. The weather during an Alert Mode threatens lives and property. Precautions to stay safe need to be taken during these events. These are among the most significant weather events our area sees, and are accompanied by widespread watches and warnings issued by the National Weather Service. The Alert Mode is meant as another way to highlight the potential dangers.

Obviously, not every significant weather event is worthy of an Alert Mode, and the decision to send Grotonweather.com into Alert Mode is taken very seriously. Only a few Alert Modes are issued each year. A combination of things has to be taken into account when going into Alert Mode:

First, the weather needs to be significant enough to create widespread dangerous conditions. Every severe thunderstorm is dangerous, and even a little freezing rain can cause deadly automobile accidents. However, most of the time, these dangerous weather events are more localized events that most Central New Yorkers are probably used to. For an event to garner an Alert Mode, it has to be above and beyond the "average" bad weather situation.

Secondly, there has to be a good deal of confidence this life threatening situation will occur. Often times, Alert Modes are prompted during an evolving situation. Such is often the case with severe thunderstorms and flash flooding. These situations will also lead to shorter Alert Mode times, as the dangerous weather is often shorter lived. Other situations, including snow and some flood events, may have Alert Modes lasting days due to the prolonged nature of the event. Typically, these types of Alert Modes can be issued further in advance due to a greater certainty of the event occurring. Still, Alert Modes will almost never be issued more than 24 hours prior to the start of an event. Instead, Grotonweather.com will go into Standby to raise awareness of the potential for devastating weather.

When an Alert Mode is issued, pay extra attention to Grotonweather.com and other weather media sources for frequent updates on the dangerous weather. The weather during these situations may rapidly change. It is strongly recommended that you become a follower of Grotonweather.com on Facebook and/or Twitter for these situations, as updates are frequently issued there. (Click here for our Facebook and Twitter pages). Often times (but not always due to other time restraints), special Grotonweather features are available during these times, including Weather Chats, Videos, safety tips and special maps.

The bottom line is this: as a meteorologist, I personally feel a responsibility to keep you informed and safe during severe weather. The absolute worst thing I can imagine is having a weather related fatality under my watch. The Grotonweather.com Alert Mode is meant to help prevent that from ever becoming a reality. If you see an Alert Mode has been issued, stay aware and "keep checking back for updates!"

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.

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!

Sleet & Freezing Rain- What's the Difference?

As posted on Syracuse.com by Drew Montreuil, 1/18/11

With icy conditions impacting Central New York this morning, meteorologists have been tossing around words such as "sleet" and "freezing rain", but what are the differences between these icy precipitation types?

For my Honor's Program thesis at SUNY Oswego, I have been investigating how the general public interprets weather forecasts, and what terminology is and is not understood. One of the survey questions I used to gather this data directly relates to today's weather.

When asked what is the difference between sleet and freezing rain, my preliminary results show that only 16% correctly understand the difference. If you do not know the difference, do not feel bad- only a little over half of the meteorology majors I surveyed fully understood the difference!

So, just what is the difference? When the water freezes. Sleet typically starts out as a snowflake while it is in the cloud. As it begins to fall, it melts into a rain drop. However, the melting is brief and, before striking the ground, it refreezes. Thus, sleet is simply falling ice pellets.

Freezing rain, on the other hand, does not fall as ice. Like sleet, freezing rain often starts off as a snowflake in the cloud, and then melts as it begins to fall. The difference here is that there is enough warm air in the atmosphere to prevent the rain drop from freezing on its way to the ground. When the rain drop does reach the ground, it freezes, typically within seconds of contact. There is one important condition for this to happen though: the air temperature at the ground must be below freezing.

While both sleet and freezing rain can cause slippery roads, it is the freezing rain that is typically more hazardous. Since sleet is already frozen when it falls, it can be plowed and shoveled with relative ease. The freezing rain forms a coating of ice on roads, cars and power lines, making it much more difficult to remove. A few inches of sleet is not a huge deal, but even just half an inch of freezing rain can bring down trees and power lines and create a very dangerous ice storm.

Blizzard Video

Here is my video update on the blizzard. Please leave feedback!

Snow Map

There have only been a couple changes to the forecast in the past 24 hours since last night's blog entry. Firstly, there is little question now that the entire storm over our area will remain as snow. The main stream of warmer air will remain north of us, and I question how far west it will make it. This makes it a very difficult forecast for Syracuse, but I think even they will remain mostly or all snow. The second change is more precipitation for the Grotonweather area. These two factors combined have given me the confidence to up my snow totals to 12-18" for most of the area. Here is my snow map for the entire storm.



I apologize for not having more updates today and not having a video, but its been a busy week at school this week. I am planning to do a video tomorrow morning though, so make sure to check in sometime after 10am. Oh, and Groton students, enjoy your day off- School has already closed for tomorrow!

Largest Snowfall of 2009-2010 Winter Looming

The largest snowfall for the Grotonweather.com area is on our horizon. This storm has consistently been on the models since Saturday, and I've just been waiting for it to become obvious that it won't happen. Over the past day and a half, I began to believe that this storm actually was going to happen, but the models remained inconsistent with the timing and exact location. There are still plenty of uncertainties to be figured out, but its time to start nailing down the seriousness of the storm. My main concern is not how much snow actually falls, but rather the blowing of the snow as the low explodes to our southeast. It will be a significant snowfall too, probably on the order of about a foot, but winds will make it seem like its snowing even heavier with near zero visibilities at times. Lets take this storm one aspect at a time.

Overall Pattern:
Low pressure is developing off the Southern New England coast this evening and tracking north. This is not the main storm. As it moves north, it will run into a sprawling area of high pressure and begin to weaken. Meanwhile, an upper level trough will dig into the eastern third of the county. This will create prime conditions for explosive storm development off the coast yet again. This low will absorb some of the energy from the dying low and continue to rapidly intensify. As it moves north towards New England, it will encounter that same high pressure, and begin to move more westerly. Over time, the storm, which still wants to move to the northeast, will do a loop over Southern New England and Southeastern New York, before heading out to sea.

Timing:
The snow will being to work into our area sometime in the morning Thursday and become heavy into the afternoon and evening. The snow will taper off in intensity Friday, but will still be around. By Saturday, everything should be pulling out, making the total time of this storm somewhere around 36 hours, with probably 12 hours of the heaviest snow.

Precipitation:
Snowfall totals are still a bit up in the air. I am concerned that warm air wraps around the system and causes a variety of precipitation types. The further to the west this storm comes, the more a concern that is. If we did change over to rain for a while, it would be later Thursday evening most likely. The models are not in agreement with whether or not this will happen, and it will have huge impacts on the total snow fall from this storm. Assuming an all snow event, which I think it probable at this time, snow fall totals should end up around a foot, give or take a couple inches. Expect a snow map Wednesday evening.

Winds:
With the low pressure coming into Southern New England and even Eastern New York, winds will become quite strong. Winds could be sustained near 25 mph for a time Thursday afternoon and evening with higher gusts. With the heavy nature of the snow, this could cause some tree damage and power outages, not to mention near zero visibilities and large snow drifts.

Temperatures:
Temperatures during the storm should stay in the upper 20s and low 30s for Thursday (mid 30s if we change to rain, but I just am not seeing that) before dropping off a bit Friday.

Stay tuned for the latest, as I will be tweaking this forecast over the next 24-36 hours. I will try to get a forecast video done tomorrow evening.

3PM Snow Video

NOTE: The watches, warnings and advisory part of the show is already out of date, with a WINTER WEATHER ADVISORY in effect for the entire Grotonweather.com forecast area, and WINTER STORM WARNINGS in the bordering counties south and east. Enjoy the video...leave comments!

Late Season Storm

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Here is the latest on the late season snow event tomorrow.

Not a whole lot has changed since this morning. The cold front is spreading areas of rain across the region this afternoon. This front extends all the way into the southeast and back towards Louisiana and Texas. An area of low pressure is developing across the Deep South and will trigger a large severe weather out break tomorrow. The Storm Prediction Center has a large moderate risk out for that:


The front that is moving through today will stall out to our east. Meanwhile, that low will fly up the front to a position near New York City by mid afternoon tomorrow. There will be just enough cold air being pulled into the storm that it should be all snow for the areas in blue on this map I created:


The low will be moving pretty quickly up the stalled front and the ground is warm, so accumulations shouldn't be huge. The change over to snow will occur first in the higher elevations, and it will remain colder there as well, so expect the highest totals there. The rest of Central New York should get a moderate snow, but not enough to cause too many problem. It will be windy as well though, so use caution traveling tomorrow as the wind and snow will create poor visibilities. Here is my snowfall map for the entire storm, which should wind down pretty quickly tomorrow afternoon.


Where does this storm rank with some other 'out of season' storms? Its actually not very impressive. In 2007, our area was hit by almost 2 feet (18" is what I measured) on April 16-17th. In early October 2006, a monster lake effect event pounded Buffalo, causing millions of dollars worth of damage since the heavy wet snow stuck to the leaves on trees and brought them down. So this is more just a nuisance storm than anything. One commonality between the three storms is the lack of willingness on the part of the media to be bold and predict snow. Granted, the models are all over the place with this, as can be expected. But I feel really confident about this storm, as I did the April 2007 storm.

I will update again late tonight. I have a test in Tropical Meteorology (so ironic, isn't it?) tomorrow, so I won't be able to update again until 10 or 11. Stay tuned though!

Groundhog Day Speculation

The meteorological community is abuzz with excitement today. Numerous models are all in agreement with a major storm coming up out of the Gulf of Mexico Monday and then sitting somewhere over the Northeast Tuesday into Wednesday. I thought that with all the hype around this storm already, people might be curious what I think.

First and for most, I will play the broken record and say what I normally do: It is WAY too far out. The models have been showing a storm and are all in pretty good agreement with that, so I do think a storm system will form in the Gulf of Mexico and move north. Beyond that point is where I feel it is too early to place much weight in the models with the track and strength of the storm.

Just to speculate though, here are a couple scenarios that could happen.

The Groundhog Day Blizzard: This scenario would take the low pressure system up the Eastern Seaboard to near New York City, where it would then sit for about 12 hours before heading north. For the first time now in a few years, the atmosphere is getting clogged at the perfect time for a blizzard. The models show an area of low pressure over Greenland, with a strong High over northeastern Canada. This will impede the progress of the coastal storm. This would be the perfect set up for probably the biggest snow storm Central New York has seen in a few years.

The Slop Storm: This scenario would have the storm coming up the Appalachians and either over northeast Pennsylvania and Eastern New York, or right over top of us in the Finger Lakes. This track would give us a mix of precipitation. Some warm air will be in place ahead of this storm, so our precipitation would likely start as either rain, or sleet and freezing rain. As the low tracked towards us, warmer air would come up, and we would go over to rain for a while. Then, as the low moved to our northeast, strong northwest winds would come in and change us back to snow for a moderate snowfall. If I had to guess, I would say this is the most likely scenario at this time. Will it happen? Only time will tell.

February Flooding: The final scenario has the low moving up the west side of the Appalachians. This would pound Ohio with a heavy snow, but for us in Central New York, it would mean a big warm up, probably at least into the 40s, with a soaking rain. Currently there is anywhere from 2 to as much as 10 inches of water equivalent sitting over top of us. That means if all the snow was to melt, that is how much rain it would equal. If even half of that snow pack melted rapidly, plus an inch or more of rain fell, there could be some major flooding problems.

Now, all of these situations focus on the different tracks of the storm. I am cautious right now about the strength of this storm as well, and do not think it will quite be as strong as the models are saying. That being said, the potential for a very memorable, if not historic storm is there. I will be watching this one closely over the weekend and early next week. Keep checking grotonweather.com for more updates!

Wednesday's Storm

I have decided not to issue a snowfall map for this storm simply because it looks like the entire area will have a pretty uniform accumulation from this. All of the Finger Lakes and Southern Tier look to be in for a good 7-12". I upped the amounts slightly from this morning based on the models bringing in more moisture than previous runs. I even saw some indications of amounts over a foot, but I think that is overdone.

All of the models are now in pretty good agreement with each other except for one. Normally, when a model is drastically different from the others, it wouldn't put too much of a damper on my confidence levels. However, this time it is the European model, which has been out-performing the other models all winter. The problem is...the Euro brings in enough warm air to cause a snow/sleet mix to occur over Central New York. My forecast totals do not reflect that happening, but if it does happen, I would think accumulations more on the order of just 4-8".

Another concern I have is my old nemesis, the dry slot. With any big storm, dry air works around the center and gets wrapped up into the storm from the southwest. If I mess up a big-snow forecast, usually it seems to be the dry slot that is the culprit. The models have this punch of dry air working across Pennsylvania during the day tomorrow, staying to our south. I imagine the counties right along the State Line have the best chance of being hit by it, meaning their snow totals may be on the lower end of the 7-12", where as the northern areas will be on the higher end. Like the mixing, my forecast doesn't have the dry slot coming in, but if the models miss and it ends up 50-100 miles further north, most areas will be hard pressed to get into that 7-12" range.

As for the timing of this storm, the snow will likely start tonight between 9-11PM. It won't take too long for the snow to get heavy, and we should have 3-5" by tomorrow morning's commute. I do not expect the snow begin to let up until after sunset tomorrow. Even then, we will be dealing with snow showers and perhaps some occasional periods of moderate snow right through the night. I would say a snow day is a decent bet for most places tomorrow, but its never an absolute. The WeatherChat will be opening sometime after 6:30 tonight and will likely stay open right through 11pm or midnight.

Dry Slotting

Snow Totals:
10AM- Dusting
11AM- 0.5"
12PM- 1.5"
1PM- 3.2"
2PM- 4.2"
3PM- 4.6"

Post:
Bad news for snow totals, good news for traveling...but the storm's dry slot is going to just hit Groton. It is racing eastward across Southern New York and should be entering Tompkins and Cortland Counties by 3:30. This should more or less end the snow.



Now, the low is forecast to start taking more of a southeasterly track, so I think we will get back into the snow this evening. However, we will be hard pressed to get to 8" I think...let alone a foot. I think 5-9" total would be a good projection for Groton now. Areas just to the north, however, that remain in the snow will stick in that 8-14" range.

Morning Storm Update

It is now quarter after 10am, and everything is going pretty much as expected. The snow started here in Groton about an hour ago, and already visibilities are down to roughly a mile as the snow has started to pick up in intensity. Looking at the official 10AM observations, Ithaca is reporting light snow, with moderate snow in Rochester, Penn Yan, and Dansville, and heavy snow falling in Buffalo. Over the next hour, expect the snow to continue to increase in intensity to the rate of an inch or so an hour. The snow will continue at least at that intensity, likely reaching 2" per hour at times, through the afternoon. Heavy and moderate snow is being reported back through Michigan. There is actually heavy snow in Wisconsin as well, but I think Lake Michigan is enhancing that snow since the winds are out of the northeast. Here is a look at the radar (from 9:30...but that is recent enough to get the point across). You can see any mixed precipitation is well south, and the snow extends back into the areas I just described. All this is moving more or less east-southeast.



Bottom line is the snow is going to come down hard very soon and continue at rates of 1-2" per hour until at least sundown. There may even be some thunder and lightning in the snow during the early and mid afternoon. Please leave a comment here, or log onto the chat (assuming it is open) and report any thunder! The chat room will likely be open most of the day today as well. I will continue to update this blog hourly, probably just with snow totals, but also any new information that comes in.

Another Friday Snow Storm

Another Friday, another snow storm for Central New York. Unlike last week's storm, this storm is not a nor' easter. It is pretty much moving west to east, so there is no worry about the models having an eastward bias. That makes my life a little easier this time around. I decided to do a snow map after all, even though the entire GrotonWeather forecast area should get the same amount.



As you can see, this will be a big storm, despite its relatively short duration. The snow will being to move in during the morning, before coming heavy by 10 or 11AM. It will really come down hard for a period of 6-8 hours, likely exceeding an inch per hour at times. By the evening, it will quickly taper off to just flurries over night.

I am going to dinner now, but once I get back (by 6:30-7), I will open the chatroom to field questions...and I will likely be there a good part of the night!

Love That East Bias!

I hinted this morning in my forecast discussion that "If it [the storm] really gets its act together, we could end up on the high end of those totals [from last night's snow map]." Well, the storm remains very impressive on satellite and radar. One thing is very evident though. The eastward bias of the models I was talking about is showing up perhaps even more significantly than I thought it would.

When I looked at the models last night, the back edge of the precipitation was roughly from a Pittsburgh, PA to Rochester, NY line. Already though, precipitation is being detected on radar as far west as Cleveland and Buffalo (though it is probably not yet reaching the ground). The low right now is over northern Georgia and is already a good one hundred or so miles further west than it is supposed to be.

The National Weather Service and local media stations have picked up on this finally and have more or less come into agreement with what I was saying yesterday. Tompkins and Cortland Counties are now under WINTER STORM WARNINGS instead of the Advisories that were in effect. Those last until 10AM tomorrow. Since the low will track a little further inland, the precipitation may be a bit heavier and last a bit longer than last night. I also mentioned this morning the possibility of expanding the 6-10" range west. As you can see, I have now done that with this new data.



After school activities have been canceled for many schools in our area. I would say that the chances of a snow day have increased a bit. It is still far from a certainty, but there is certainly cause for hope!

Also, if you haven't heard yet, I have a new feature on the site that I just added this morning. If you look to the black bar on the right side of the page, you will see a link to the 'GrotonWeather Weather Chat.' The text will either say the chat is open, of that it is closed. If it is open, it means I am sitting in the chat room, ready to give you whatever information you want to know about the weather! So, if you see that the room is open, come on in!

Snow Map

11AM Update: I just added a new feature to the website....a chat room! The link to the chat room can be found in the black bar on the right side of the page. More often than not, I will have the chat room closed. But, during times of severe or extreme weather, when I am on my computer forecasting, I will open up the chat for you to ask my questions about the weather. Please click the link to the right for more details...and if the room is open, stop in and say hi!

10:20AM Update: I have updated the main forecast page as promised. Next blog should be sometime between 4-7PM...probably sooner rather than later!

Original Post:
At last, here is the snow map. When one of the models came in, it still had the storm way east, with Ithaca getting an amazing 0.07" of snow from the storm. That isn't the model I prefer to use on a day to day basis anyways though, so I didn't put too much stock into. The model I do use takes a bit longer to become available (since it goes out a lot longer), so that is why the map has taken so long. That model seems to be settling in nicely with my earlier predictions now.

The temperatures during this storm are going to generally be in the upper 20s to near 30. Since wet snow doesn't accumulate as much as drier snow, I slightly lowered totals from what I pulled out of thin air earlier. As for snow days, at this time, I would probably say its a good idea to expect school on Friday, but someone in the area will likely wake up with a nice surprise three-day weekend.



My next update will likely not be a blog entry, but just my normal morning forecast update. Just click the banner at the very top of the page to see that.

Here we go!

Winter Storm Watches have (finally) been posted for the grotonweather.com forecast area! I say finally because, if I had been working at the National Weather Service, I would have issued these watches yesterday. All season long, and going back into last season, the models have shown an eastward biased with storms coming up from the south. This is a large part of why a lot of last winter had a lot of hype about snow storms (myself included), only to have the storms start as snow, then change to ice and/or rain. The actual storm tracks have continuously come further west than the models suggest. So when I saw the models showing snow for Eastern New York and New England yesterday, I thought 'Thats going to hit CNY'....and now, it looks like it will.

The NWS has Winter Storm Warnings up for areas just south and east of us. I again have to say though...they are too far east! Even just a day or so ahead of this event, I do not trust the models to place the heaviest snow properly. So, I am diverging from them and the NWS and, while I haven't checked them, likely the local media as well.

So, what is this all about. An area of low pressure is over the southeast. As I said in this morning's discussion, severe thunderstorms, including torandoes, have been ongoing constantly since yesterday morning. This is indicative of the energy of this storm. As this storm comes up the coast, it will interact with the cold air left over from today's front, with the circulation just pulling more of it in. It will be a classic nor' easter...just not super powerful.

Snow will likely begin to fall in our area sometime in the late afternoon tomorrow and become heavy into the night. This storm will be a pretty quick mover, so that will help in keeping totals down. I also think that, even with the eastward biased, the heaviest snow will stay just east of our area. I haven't had enough time to hammer out a snow map yet, but, on a whim, I am thinking 5-9" is likely for most of Tompkins County and Southern Cayuga County, with perhaps 6-10" over Cortland County.

And now...what you all really want to know....will there be school on Friday? After my epic failing on predicting a snow day last February, I considered not even doing snow days this season...but, due to popular request, I will. Since this storm is coming through at night, I would say there is certainly a chance. Just how much of a chance remains to be seen. You will have to keep checking back to find out!

Next projected update: 10-11:30PM: Snow map!

3PM Snow Update

Sorry this update is a bit later than I promised. I ran into some difficulties with making the snow map.

The lake effect has been pretty disorganized through the day as winds haven't really aligned themselves well yet. The models showed this happening relatively well. This disorganization should continue until about sunset, when things really start to get going. I am expecting multiple bands of lake effect to form, with probably two main bands. They will move around a bit overnight, so plenty of areas should see some high snow totals. Here is what I am thinking for amounts by 9AM tomorrow morning:



As with any lake effect event, not every area within each contour will get that amount of snow and the variance from one spot to another can be very large. So, that snow map shows the most likely amounts that are to occur in each area.

Tomorrow, the lake effect should calm down as the day gets into the afternoon. Additional accumulations tomorrow will likely be anywhere from 1-4" in the white and light blue areas, to 3-7" in the darker blue.