Late-May News and Updates

Hello Grotonweather Fans! I have been working very hard over the past couple of months on new and exciting things. I thought I would type up a blog to explain and promote some of these things.

First off is Finger Lakes Weather (www.fl-weather.com), my new weather forecasting and consulting business. It is my hope that Finger Lakes Weather will become my career, helping local businesses, organizations, and the public with private and customizable weather forecasts. Finger Lakes Weather offers a variety of "Forecast Packages" tailored specifically towards various groups. For the spring, I offered a frost forecast package and was able to do some free-trial forecasting for Fox Run Vineyards and Three Brothers Vineyards, both on Seneca Lake. I have plans for a forecast package for construction workers. Right now, I am offering a special on vacation forecasting...but more on that later. Check out Finger Lakes Weather (the website again is www.fl-weather.com) and join the Finger Lakes Facebook page.

Next up is the Grotonweather Radar Page (www.grotonweather.com/radar). I recently got some top-notch radar software that is used by many meteorologists, especially storm chasers and others interested in thunderstorms. This software allows me to upload the radar to the website, so that is what I have done. Furthermore, I can display things such as areas of possible hail, rotation in thunderstorms, winds, and watches and warnings. I can also zoom right in on a storm down to street-level. So far, this has been a HUGE success with hundred of views despite an overall quiet thunderstorm season thusfar.

A severe thunderstorm approaches Ithaca.

Success does not come without price, however. And in this case, the price is measured in bandwidth. For those not familiar, bandwidth is basically the amount of data transferred to and from a website. The radar page uploads large image files every few minutes and quickly ate up my monthly bandwidth limit. That in turn forced me to purchase a more expensive hosting plan. My costs for running Grotonweather.com, not including time spent, is now approaching $200 a year.

Since 2006, when I started this operation, I have not received any revenue from my website. I am dedicated to keeping the website free. As costs continue to rise, something has to be done to offset some of these costs. Rather than charge money for Grotonweather and rather than flat out asking for donations, I decided a fund-raiser would be the best idea.

This is where the vacation forecasting package from Finger Lakes Weather (www.fl-weather.com/vacation) comes back into play. As a fund-raiser, I am offering this service at a reduced price of just $10 per day or $50 per week. What does that entail? I will forecast for your travels to and from your vacation destination. I will forecast for you each morning of your trip so that you can know what to expect. If you have plans to engage in a certain activity- whether a day at the beach, a horseback ride, a bicycle tour...anything at all- I will forecast specifically for that activity and how the weather might impact your plans.

Furthermore, I will do severe weather forecasting for you. Say you are driving down the highway in Kansas and you see storms ahead. You can give me a call- no matter what time of day or night- and ask me if they are severe. Or, if you are enjoying your vacation (which you should be!), but storms (or a hurricane!) are coming, I will reach out to you and let you know.

I think this is a really neat and unique service and I believe it will help you make the most of your vacation. And it would really help relieve some of the costs I have. So please, consider signing up before June 10th to get the sale price. Even if your vacation is in August or later, book it now. Here is the link again: www.fl-weather.com/vacation

Moving on now, I am slowly working on a redesign of Grotonweather.com. I am really excited about how it looks so far. I did a survey a couple of weeks ago on displaying confidence and uncertainty in forecasts. The results were a tremendous help, so thank you to all who participated! I am now doing a smaller follow-up survey on a proposed forecast layout change. Please, if you could take a moment and fill it out, I would be very grateful. Here is the link: www.grotonweather.com/survey

If that was all not enough, I also started a new project on Facebook in an attempt to 1) combine my strong religious beliefs with my love for the weather 2) help those threatened by severe weather on a national level and 3) expand my forecasting beyond just the Finger Lakes. The result is the Storming Heaven Facebook group. If you believe in the power of prayer, go ahead an join up.

Back in late March, the Groton Public Library invited me to give an hour-long presentation. I presented on the Blizzard of 1993. Thank you to the library for the opportunity to speak! If you would like me to speak at your event or in your class (I've spoken at 3 schools since November), just send me an email or let me know on Facebook!

Thank you for reading this long post and for your continued support and interest in Grotonweather.com and the other projects I am working on. Stay tuned for more great features coming up...I am only getting started!!!

No Alert Mode this time...

A potentially significant severe weather outbreak across much of the northeast, including our area is beginning. However, Grotonweather.com will NOT be going into alert mode for this event. As I mentioned in the Alert Mode blog, I take the issuing of Alert Mode very seriously. I only issue them when it seems like widespread, life threatening weather is likely.

Today's event is very close to that criteria, and I cannot say for sure that I will not issue Alert Mode status later in the day. At this point though, I do not think the storms will organize quite fast enough to bring the high risks necessary for an Alert Mode. If this site was for Chenango, Monroe and Otsego counties, I very likely would be going into Alert Mode. The worst of this event, in terms of spatial coverage and intensity, will likely be just to our east.

That being said, storms are already starting to develop in our area and just to the west. These storms will not take long to become severe, and our threats for wind damage and hail remain at a 'MODERATE' level. Winds up to 80mph and two inch hail are not totally out of the question. Stay tuned for updates!

Severe Weather Awareness Week

This week is Severe Weather Awareness Week. In light of the recent severe and tornadic thunderstorms, I think its very important that we realize that dangerous and deadly weather can and does occur in our area. The first step to keeping yourself safe is education. I will be updating this blog each day with links to the National Weather Service pages for each day of Severe Weather Awareness Week.

Monday- Overview
Tuesday- Severe Thunderstorms
Wednesday- Severe Weather Preparedness
Thursday- Tornado Watches & Warnings
Friday- Flood Preparedness
Saturday- Communication of Hazardous Weather Information

Monday's Historic Thunderstorms

Story originally published on Syracuse.com by Drew Montreuil.

I wanted to take a couple moments and point out some pretty amazing things that happened Monday across the eastern half of the nation. A huge severe weather outbreak blasted across the Ohio and Tennessee Valleys and into the southeast. Severe weather was reported from Texas to Florida, northward into Pennsylvania. Even here in Central New York, we had a few strong thunderstorms. Three-quarter inch hail was reported Monday morning near Ithaca and in Norwich. Hail must measure one inch in diameter before it is considered "severe".

While the National Weather Service continues to do surveys of the damage, the number of reports will continue to increase. But here are some numbers that are just mind blowing:

As of 10AM Wednesday, there were 1377 total reports of wind damage, 1"+ hail or tornadoes from Monday. Since 2000, there has not been a single day with this many severe weather reports. Of the nearly 1400 reports, 1245 were damaging wind reports. The squall line responsible for this outbreak did not stop producing severe weather because it died; it simply moved off shore over the Atlantic Ocean. Unfortunately, there were a number of fatalities associated with these storms as tornadoes destroyed homes and trees were downed onto houses. The image above, from the Storm Prediction Center, shows the severe weather reports from Monday's historic outbreak. Blue dots represent wind damage, while red dots are tornado reports and green dots are hail an inch in diameter or greater. Click the image for a larger view.

More spring-like weather will be on the way for the East, including Central New York. Another powerful storm system will form over the Great Plains this weekend and head up into Canada. A cold front will blast across the Midwest, Southeast and Northeast, with more severe weather possible. Currently the Storm Prediction Center is highlighting areas from Minnesota and Wisconsin south to Texas and Louisiana and eastward to Ohio, Kentucky and Tennessee as the highest potential for severe weather. As we get closer to the weekend though, I would not be surprised to see that threat shifted further to the east. Whether or not we get into the thunderstorms once more is still a bit questionable, but at the very least, our temperatures will shoot into the 60s, maybe even near 70 Sunday and Monday.

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!"

Video: Severe threat update

Into the Moderate Risk

The Storm Prediction Center has moved our area into a "moderate risk" zone. This is their 3rd of 4 severe weather categories...and the 4th and final one is rarely issued anywhere, and I cannot say that I have seen it used up here. I would say we see a moderate risk every other year or so. Sometimes we get in a pattern where we get a couple in a short time span, but then there are occasions when we don't get any in a whole year. So, in conclusion of all that...when the SPC puts out the moderate for our area, its time for me to really look at things.

So what is going on that has prompted this? A strong area of low pressure with strong winds aloft will be moving eastward towards us overnight tonight. This system has produced plenty of severe weather already. Currently, there is a line of thunderstorms stretching from Michigan down into Indiana, then stretching back into Illinois and Iowa as the low moves across Wisconsin. These storms will not effect us. The part of the line moving across Michigan will turn southeast and die out. However, in its wake, new storms will develop later this afternoon and form into another cluster. This cluster will move eastward into Western New York later this evening and into the first part of the night and then towards our area after midnight. As it crosses Michigan, southern Ontario and into western New York, it will be producing widespread damaging winds...and it is for that reason that the moderate risk has been posted.

The question for us, on the far eastern edge of the moderate risk, is whether or not the line's severe potential continues overnight. We are in the 45% range for damaging winds. That percentage means the SPC thinks there is a 45% chance of damaging winds within 25 miles of a point. Statistically, from the center of the Grotonweather forecast area, a 25-mile radius covers the entire forecast area and some...so we can assume just a slightly lower probability of damaging winds in our area...very roughly 40%. That may not seem like a very high chance, but in reality, it is. I, however, am not so convinced, and would put the threat at maybe 20-30%. Here is why:

By the time the storms come over here, it will be well after dark. Typically, this would be very unfavorable for any severe weather with the loss of the daytime heating. However, our instability will actually increase overnight and, if the models are correct, peak sometime near or after sunrise tomorrow morning. From what I have been seeing on the models, the line should run our ahead of the main instability and thus weaken itself. Additionally...it will also likely outrun the upper level forcing and stronger winds aloft, which also come through tomorrow morning. If the timing of these matched up better, I would be more convinced a once-every couple years event was indeed unfolding.

Does this mean severe weather is not possible tonight? Absolutely not. These complexes of thunderstorms often develop their own mechanisms for keeping themselves going. If this were not the case, I wouldn't be overly concerned at all. Our instability will still only be marginal to moderate and, as I said earlier, the forcing and upper level winds aren't quite as good as a real classic event would have them. But since these things have a life of their own, there very well could be damage across our area overnight tonight. I do not feel at this time that the damage will be widespread, and certainly not on the scale of our area's most infamous overnight line of storms: The Labor Day 1998 event that destroyed the New York State fairgrounds.

Bottom line is this: Sometime after midnight, a line of thunderstorms should roll through our area. Frequent lightning, heavy rain, maybe a little small hail and gusty winds are likely. Some wind damage is not out of the question, but shouldn't be widespread. Rain and thunderstorms may continue to impact the region tomorrow morning though. Some models have shown very heavy rain in here tomorrow morning, so flash flooding could become a threat.

If anything looks like it has changed, I will post another update this afternoon. Otherwise, an update will be issued around 9m tonight to see how things have evolved through the day.

Tornado Watch to the south

An early morning tornado watch is in effect for the counties just south of Tompkins and Cortland counties down through Pennsylvania and Ohio. There are severe thunderstorm warnings for those same counties (Chemung and Tioga specifically) as thunderstorms out ahead of a cold front move across the area. The cold front is back over Western New York/Pennsylvania, with the low itself sitting over Western New York. With severe storms and a tornado watch on our doorstep, I felt a blog update would be more prudent for today.


As the cold front and low move east this morning, the wind fields will definitely be supportive of possible tornadoes, if more thunderstorms can form along the front. While I do not think there is enough instability this morning...and with all the clouds around I do not foresee us destabilizing...with the potential for a short lived tornado or two if storms were to form, I have to at least mention the possibility. What will likely happen is the cold front will move east of us and some more showers, maybe even a rumble of thunder, will effect us from time to time today. Keep a look out though, and listen for any potential warnings. The best chance for severe weather will be between now and the early afternoon. Beyond that, the front will move through and temperatures will drop, likely ending up in the 50s by sunset.

Ticking Time Bomb

I like severe thunderstorms. They are fun to try to forecast and I find them exciting to experience. I of course don't like it when they do major damage or pose a significant threat to the safety of people. So, you could say there is a certain intangible threshold where a situation goes from enjoyable, to scary. I think we've already crossed that threshold today, and the nearest storms are just starting to pop in eastern Michigan.

Now, if you checked my site early this morning, you would have seen that I had taken it down and had prepared it to sit dormant for the next 10 days or so due to a variety of circumstances. However, things are evolving in such a way that I really feel like I need to be updating today.

Ok, so whats going on. If you haven't stepped outside lately, go do so. You will be greeted by a blast of heat and oppressive humidity when you do. Temperatures have already shot up into the 80s, and dewpoints are in the low 70s. This has already led to instability levels that are rare for our area, and high even by the standards of the Great Plains. So often, I talk about the role of cloud cover in severe weather outbreaks. Often times in our area, clouds in the morning and early afternoon inhibit destabilization, which is why we don't see extreme instability like we are seeing now very often. But it has been sunny and will continue to be sunny through the afternoon, which means things will only continue to destabilze to levels that far exceed anything we have seen this year, possibly even the past few years.

Instability alone is not enough to create a severe weather outbreak. You also need a trigger to get storms going. For us, that is a disturbance moving towards the east along a cold front. Right now, it is over southern Michigan...which is why the storms are forming there. As it moves east, this energy will provide the lift needed to allow storms to continue to form. As they interact with the unstable air, they will intensify. One more piece is needed though, and that is shear, or a change in wind speed or direction with height or horizontal distance. In this case, we are looking at speed shear from both the ground up into the atmosphere, and horizontally from south to north. This is because of an area of strong winds in the jet stream called a 'jet streak' that is to our north. This will provide the shear needed to organize the storms into segments, or even a squall line.

The way I see it right now, all of the ingredients are evolving to come together for a significant severe weather event for all of Central New York. The only question I really have is whether or not a massive squall line will form out of those storms in Michigan, or if there will be multiple, but smaller lines of storms. That is something that will only be determined as the afternoon goes on. Regardless, there is the potential for strong, destructive winds after roughly 4pm tonight. It wouldn't hurt to take some precautions now by putting away lawn furniture, securing loose objects, etc. The biggest threat from the storms is definatly wind and, if I was updating my site as normal, I would likely place it in the 'high' category. I believe that most, if not all counties in Central New York will experience at least some wind damage to trees.

Another danger tonight will be flash flooding....some areas, especially in Cortland County, got 3"+ of rain yesterday, with mudslides and road closures overnight in Cortland County. It won't take much heavy rain to create more problems. NEVER drive through a flooded roadway! Flooding is the number 1 weather killer in the United States, and most of those fatalities occur in automobiles.

Watch for another update between 3 and 5pm, or sooner if a watch comes out. This is one forecast I hope I am not right on.

Risks Upgraded

There have been a couple of changes in the forecast this morning as things area already rapidly evolving. Probably the most significant of these changes is that, instead of all the clouds and rain the models had been forecasting for us this morning, skies are clear. This is causing the atmosphere to destabilize quicker and more intensely than had been forecasted. Another thing to look at is the radar. Thunderstorms are widespread just west of Buffalo, and already, there are some storms popping out ahead of this main area...so the question of whether or not storms will form is out the window.

The Storm Prediction Center has us in a 30-30-5% risk for wind-hail-tornadoes, respectively. All three of those are on the upper end of their 'slight' risk category. After looking at a couple things, I moved my hail and win up to moderate, and kept tornadoes at slight. Since storms are already firing, I moved the thunderstorm risk all the way up, which the NWS in Binghamton also did on their threat outlooks.

Here is what I am expecting for each threat:

Thunderstorms: Extreme-
Widespread thunderstorms can be expected with almost everywhere getting a storm. Frequent lightning should accompany the storms, and a fair number of them will likely be severe.

Wind: Moderate-
With the sun out this morning and strong upper level winds, wind damage is likely somewhere in Central New York, with some possibility of widespread damaging winds. 3 to 7 damaging wind reports are possible in the Grotonweather forecast area (Tompkins, S. Cayuga and Cortland Counties), with more elsewhere in Central New York. Should a widespread wind event evolve, this will be increased to high.

Hail: Moderate-
With extra instablity from the sun this morning, and indications of favorable hail formation from both the models, and current observations, hail could become a major factor today. 3 to 7 severe (0.75" of bigger) hail reports in the forecast area is possible, with more elsewhere in Central New York. Hail sizes should stay below 1.5", but an isolated storm could produce up to 2" hail. An upgrade to a high risk is not expected at this time.

Tornadoes: Slight-
Little changes to the tornado forecast have been made. A tornado somewhere in Western and Central New York seems almost likely. Multiple tornadoes could be possible, but this certainty isn't enough for a moderate risk at the time. However, with strong southeast winds at the surface, winds at low levels out of the southwest, and upper level winds coming in from the west, the threat for tornadoes will need to be watched closely.

Friday Afternoon's Severe Weather Outlook for 7/11

I spent the morning and early afternoon down at the National Weather Service in Binghamton, where I am an intern this summer, and used some of their in-house tools to try to get a better handle on the severe weather threat tomorrow. I will mention that the meteorologists there this morning believe tomorrow will be an active day and seem to have a high confidence level.

One of the tools I used this morning was a form called the 'severe weather checklist'. This form has you enter in forecasted values for a variety of severe weather parameters. After doing so, it returns the 5 most similar severe weather days in recent Central New York history. When completing this checklist this morning, it returned 4 days of 'isolated supercells', including May 16th, 2009, which had 3 tornadoes in the area, and May 31, 2002, which had 4 tornadoes. The fifth day was classified as a 'broken line'. Hail was the primary threat from the five days collectively. That tells me that not everywhere tomorrow will see a strong thunderstorm....some areas may barely even get any rain. However, there is certainly potential for some severe weather, and someone will likely have to deal with a damaging storm.

Here is a glance at where I have my threat levels, and an in depth look at exactly what I mean by each threat level, as well as what would need to happen for an upgraded risk:

Thunderstorms: moderate-
Thunderstorms are likely across much of the area. A few places, however, will be missed and get little to no rain. Frequent lightning will accompany some of the storms.

High Winds: slight-
Some storms may contain strong winds. Wind damage will be isolated to scattered, with 3 to 10 reports in Central New York. Sunshine in the morning would increase the chances of wind damage, and could get this bumped up to a moderate risk.

Hail: slight-
Small hail will be possible with stronger storms tomorrow, but most hail should remain uner 1" in diameter. The strongest storms may produce up to 1.5" hail. 5-12 Severe hail (over 0.75") events can be expected in Central New York. This is still rather uncertain, and could be upgraded to a moderate risk should the models show a bit better conditions for hail tomorrow morning.

Tornadoes: slight-
Conditions are favorable for rotating storms, and tornadoes could form. My best current guess is that somewhere in Western, Central and Southern New York will see a weak tornado, but as many as 2 or 3 wouldn't surprise me. This would most likely not be upgraded to moderate unless numerous storms that have already developed are showing signs of becoming tornadic.

Expect the next website update to occur between 9 and 11 am tomorrow. A blog update should occur within 30 minutes of that. There also could be a quick blog update tonight. During the afternoon tomorrow, I plan to have the weather chat open and will be updating th blog and website as needed. Stay tuned!

Severe Storm Potential

I am very impressed with the atmosphere this morning and feel like this is perhaps the best severe weather set up we have had so far this spring. There is a cold front draped across eastern Ohio this morning that will move eastward and trigger thunderstorms. Ahead of that front, skies have cleared across western New York, creating an already unstable atmosphere even more so. I was surprised to see the instability indexes so high already this morning. You did not need me to tell you that, however, as the humidity this morning is making it feel very uncomfortable and muggy.

The main threat today is going to be large hail and damaging wind gusts. However, conditions also appear favorable for a tornado or two to form, so you will want to keep an eye to the sky. The Storm Prediction Center does not actually have us in a slight risk area today, for reasons that are beyond my understanding. I feel that the will reverse their thinking as the morning wears on and, with their 12:30pm update, add us to the slight risk area. You can check that by clicking here.

I will not be able to update this during the afternoon today. I will actually be down at the National Weather Service in Binghamton on my first day as a summer intern there. I do not think there could have been a better day for me to start, and I believe it will be a very active day down there. Click Here for the latest watches and warning, and click here for a look at the radar.

A Look at Watch #280

The Storm Prediction Center has issued a Severe Thunderstorm Watch that stretches across almost all of New York State. It remains in effect until 7pm tonight. Here is a look at the exact counties it includes. As you can see, Tompkins, Cortland and S. Cayuga are right in the middle of it.


The main threat from this event is going to be damaging winds. Hail will also be possible, and my gut feeling is there will be a tornado somewhere in the watch box. The official probabilities that the SPC has put with the watch:
Tornadoes

Probability of 2 or more tornadoes	Low (20%)
Probability of 1 or more strong (F2-F5) tornadoes	Low (5%)

Wind

Probability of 10 or more severe wind events	Mod (60%)
Probability of 1 or more wind events > 65 knots	Mod (30%)

Hail

Probability of 10 or more severe hail events	Mod (30%)
Probability of 1 or more hailstones > 2 inches	Low (20%)

Combined Severe Hail/Wind

Probability of 6 or more combined severe hail/wind events

High (80%)

Since it is at the top of the hour, the current observations and indicies will not be in for another 20-40 minutes. Looking at the data from noon, though, it is obvious to me that the atmosphere is quickly destabilizing. Also, a pocket of strong winds in the upper atmosphere is beginning to move into Western New York, and will spread over the rest of the state, enhancing the thunderstorms. Storms are going to develop from west to east, and have already begun to fire up across Western New York, Lake Erie and Lake Ontario. These storms should organize into a squall line eventually, which is when the greatest threat for wind damage will be. The highest tornado and hail threat will be just prior to that, when the storms are more individual cells.

Be sure to keep checking back through the afternoon for the latest!

First Watch of the Season!

12:45 Update: Severe Thunderstorm Watch issued! Full blog post analyzing the situation coming...

The Storm Prediction Center has outlined Central and Eastern New York as an area where a weather watch will "likely" be needed. The watch will likely be issued by 1PM. Stay tuned! I am watching this carefully and will have the watch up on the site within moments of its issuance!

>Click here for your full forecast

Late Season Storm

Click here to return to the homepage

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!

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.

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!

Abnormal September Tornado Threat

I can't say I saw this one coming, but I get up this morning and almost everything I look at points to today being a rough day across parts of Central New York. Last year in meteorology class, we went over tornado forecasting in quite some detail. A lot of the things we were told to look for have started to line up. The one thing that will probably prevent this from being an outbreak is the fact that the air aloft isn't all that cold. That warm air aloft should help keep the instability less than it would be on other days that are this humid. Regardless to say, the Storm Prediction Center has us in their '5%' chance of tornadoes.

There are meteorologists, however, who do not like the SPC's % system. One of them is Accuweather Senior Meteorologist Henry Margusity, who I have mentioned many times. Over the summer, he developed a scale to better address the threats of severe thunderstorms. His scale goes from 1-4 and outlines specific threats for each category. You will likely have to click the image to read it, but here is a look at his system:


Henry has placed us in his T3 Category today mainly for the tornado threat. It will be interesting to see how this one unfolds. Stay tuned!

Split Forecast Area

The grotonweather.com forecast area has been split by Severe Thunderstorm Watch 638. Cayuga County is under the watch, while Tompkins and Cortland got left out. In all honesty, however, that is just a technicality. Conditions are just as favorable for severe thunderstorms in Tompkins and Cortland Counties as they are in Cayuga...the SPC has to draw the line somewhere, however. I am expecting another watch to be issued later this afternoon that will include the rest of the area.




Numerous thunderstorms have developed over Western New York and Western Pennsylvania. These storms will track east, with damaging winds and hail the main threats. Other storms will develop as well, so it looks like we may have a decent severe weather event on our hands.

Severe t-storm approaching!

The National Weather Service in Binghamton has issued a Severe Thunderstorm WARNING for Northern Tompkins County and surrounding areas. This includes Groton. A large thunderstorm, likely containing hail, is currently just west of Cayuga Lake, moving east. Expect torrential downpours, hail and frequent lightning with this storm!