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.

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.

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!

Not Done Yet

One round of severe storms has exited the region and pressed eastward. This line didn't look like it was going to do much for Tompkins, Cortland and Southern Cayuga counties, but right as it got here, it exploded rapidly. Just shows what a little bit extra heating and humidity can do for storms, as tempertures before the storms had reached into the mid 80's. These storms have caused quite a few hail and wind reports, as expected. Here is the storm report map as of 1:02PM.


Tempertures are back into the low 80's after about a 15 degree drop with those storms. That means we are certainly still have fuel to work with for the rest of the day. Thunderstorms are also now starting to develop well to our west along the cold front in Ohio. They haven't been going for long, but are already looking strong and developing into a line. This is what I have expected to happen, so everything still looks favorable for another, possibly more intense, line of storms later this evening.


In between then and now, additional storms are possible, also with damaging winds and hail. I'll continue to update through the day, so stay tuned!

MOD. RISK!

A very serious situation is unfolding today for our area, with the Storm Prediction Center placing us under a MODERATE RISK zone. To put this in perspective as to how rare this type of severe weather outlook is for our area, I can only remember 1 other time during the lifetime of grotonweather.com that we have been under a moderate risk, and NEVER have we been under one to start the day! I do have to say, however, that I was thinking last night that this would happen. Here are the areas under the moderate risk (pink in the top image) because of the wind threat (red in the bottom image).


As I have been indicating the past 24 hours, everything is coming together for a major severe weather outbreak. Hot, humid air is and has been in place. This will interact with a cold front and trough of low pressure that will progress eastward through the day. The final piece to the puzzle will be the strong jet stream winds. The thunderstorms that explode later this morning across Western and Central New York will be able to tap into these winds. Winds in some of the storms today could exceed 70, even 80 or 90 mph. The tornado threat is a tad higher than I thought last night as well. I will be updating throughout the day, so make sure to stay tuned here for the most up-to-date, in depth forecasts and outlooks you will find on the web for this area!

(Your normal forecast will be coming by 8AM. To find the forecast, hover over the "Grotonweather" tab in the menu above, then click the "Homepage" link!)

Round Two Begins!

The clusters of thunderstorms that moved through earlier today have shifted well off to the south and east. While these storms stabilized the atmosphere for a while, in the long run, they only made things worse. Over an inch of rain fell in Groton earlier. Now, with the sun back out, that inch of rain is returning to the atmosphere. Dewpoints have shot up into the mid to upper 70's, making it feel over 90 despite temperatures being in the low to mid 80's. All this moisture is fueling another round of thunderstorms which is just now starting to explode.

Right now, most of these storms are in the southern counties of New York, but there is a large cell over Lake Ontario as well. Further rapid development of storms is certainly possible over the next few hours. There is currently (4:30) a small cell near Trumansburg that will have to be watched for rapid development in the next hour or so. A severe thunderstorm watch remains in effect as well.

Looking into this evening and overnight, there is a very strong line of severe thunderstorms over Michigan right now. These storms have a severe thunderstorm watch for Michigan, and a torando watch issued by the Canadian Weather Service for Southern Ontario. It is hard to say if this line will hold together long enough to effect us, but it is something I will be watching through the evening.

On this radar image (from weathertap.com) you can see the numerous cells firing up in New York, along with the line of storms in Michigan marching eastward.

Storm Reports, May Stats

While there wasn't a whole lot of widespread severe weather yesterday across Central and Western New York, the one area that did seem to get hit hardest was in fact our area. Most of the grotonweather.com forecast range (Tompkins, Cortland and Southern Cayuga Counties) ended up under a severe thunderstorm warning at one point or another as two separate severe storms crossed the area.

The first storm tracked across Southern Tompkins and Cortland Counties in the early afternoon, well ahead of the cold front. This storm produced numerous hail and wind reports, especially once it moved into Broome and Chenango Counties. The second storm came through at about 6pm. This storm took out trees in Cortland and Locke, while hitting West Groton with 3/4" hail, with some smaller hail in Groton.

I have overlayed yesterday's storm reports on Google Earth and marked a few of the towns for reference. The blue circles with a "W" represent a wind damage report, while the green circles with an "H" represent hail. Not a huge outbreak by any means, but considering the lack of severe storms elsewhere, we got hit decently hard.


Onto other things now...did you think May seemed abnormally cold? Well, if you did, you are correct. In fact, the differences between this May and last May are quite staggering. Our average high this May was a very chilly 64.0 degrees. This ended up 12 degrees colder than last May, which averaged 76.1 degrees. In fact, there were only 3 days in which our high this past month reached 76 degrees! (Those days were the 7th at 76, the 26th at 82, and the 31st and 76). Our warmest day this May was 82, much lower than last year's 92 and even lower than 2006's 95 degree day. On the whole, it was the coldest May on my records (2003-present) by three degrees. We also had our coldest nights, with our average lows falling below 40 for the first time.

Memorial Day Storms

The new website isn't quite ready to be launched yet, but there is some important weather to talk about today.

There are some clouds moving through this morning along a warm front. This front will bring us some real summer like weather for the rest of the day. Heat and humidity will move in this afternoon. Highs should end up in the mid 80's with dew points in the mid 60's making for a rather sultry day compared to the weather we have been having. As this front passes through, there could be a shower or thunderstorm.

However, later in the evening, say after 4pm, there will be another chance for thunderstorms to develop in the warm, moist atmosphere. These are the storms that have prompted the Storm Prediction Center in Norman, Oklahoma to put us in a "slight" risk for severe thunderstorms. The main threats from these storms will likely be damaging winds, hail, frequent lightning and flash flooding, though an isolated weak tornado can't be ruled out.

These storms will be forming in the "warm sector" well ahead of a cold front. That front will move through overnight and early tomorrow morning, likely with another batch of showers and thunderstorms. However, the most likely time for severe storms will run from roughly 4pm-midnight tonight. Stay tuned for updates through the evening for storms that become severe! And hopefully I will get the new site up by this evening as well!

Awesome Satellite!

Before I get to the point of this post, I would like to recap Friday's Severe weather..and why we didn't get any. If you recall, I was quite excited before hand about the potential for some major severe weather. However, there were too many clouds and too much rain to allow for things to fire up. By early afternoon, I had narrowed my prediction to roughly 15-20 storm reports across the whole Northeast and Mid-Atlantic. Here is the storm report map from Friday so you can't say I totally messed up the forecast! *laughs*



Now, onto the point of this post. I was looking at some satellites imagery today and I zoomed in on Southern California, which has been in the news with winds over 100mph and massive forest fires. You can clearly pick out the smoke from the fires blowing out over the Pacific Ocean. I haven't figured out how to get it to loop on here yet...if I don't figure it out and you want to see it, let me know and I can send the loop to you!


Now, it seems we hear about high winds and fires in southern California every year around this time. Often times, the media blames the "Santa Ana" Winds, and rightly so. But what are they and why are they so destructive? Accuweather does an excellent job explaining this phenomena. I would simply link to the story, but since it is one of their headline stories, the article will likely no longer be available in the next day or two. So, here is a screen shot of the article, courtesy of Accuweather (click to enlarge!):

Here we go again!

A SEVERE THUNDERSTORM WATCH is in effect for all of Central and Eastern New York until 9 tonight! The probabilities of damaging winds and hail are very high and it looks like everything is coming together in the atmosphere for a big severe weather outbreak. As of 2PM, there are only a couple of cells around. These cells will continue to form through the afternoon. They will then probably form into squall lines. Damaging winds are the largest threat, but hail and torrential rains are likely as well. There could also be a tornado or two around the region. More updates as things develop! Stay tuned!

The week ahead, plus a bit of history!

This blog post will have two parts. The first part will focus on this week's weather pattern across most of North America. It is an interesting set-up and I will explain what it means for us, especially come later next week into the weekend. Then, I will take you back to this weekend last year. If you thought this past week was rainy, wait until you hear the rain amounts we got last year!


This image tells some, but not all of the story. High pressure to our west will bring us seasonable temperatures for the first half of the week. Meanwhile, on the back side of the high, heat will be building big time, with triple digits all the way to the Canadian border! What this map doesn't show is an upper-level low that will be hanging around the mid-Atlantic and Northeast. This will not only bring scattered thunderstorms, possibly severe with hail, but it will also clog up the flow of weather systems. Usually, systems travel west to east. However, this low will dig in an be very stubborn, forcing the high pressure, and the heat, north into Canada. This will allow the hot airmass to become very strong. Eventually, the low will lose out and be broken down and the heat will come spilling east. This will probably happen later this week, and when it does, we will bake!


July 21st and July 22nd, 2006: A frontal boundary was stalled across the region, with cool air to the north and hot, humid air to the south. We were stuck in the middle of these air masses, right in the battle zone. As low pressure systems moved along this boundary, thunderstorms broke out and "trained" across the region. "Training" is when repeated thunderstorms move over the same area, over and over again. This usually results in excessive rainfall, as was the case last year. On the 21st, thunderstorms rumbled through Groton for most of the pre-dawn hours. These storms dumped 1.14" of rain. Then, the next morning, the same thing happened, but with more numerous and stronger storms. As a result, the 24-hour rain record for Groton (according to my rain stats, which I have been keeping since 2004) was crushed by noon. Those storms dumped 3.31", with another 0.04" coming later in the day. As a result, our two-day rainfall was a whopping 4.49"! By comparison, our four-day rain total this week (Tuesday-Friday) was 1.38".

Have a nice weekend everyone!

Severe threat not gone

Today's threat for severe storms isn't gone...in fact, it is just getting going. Thunderstorms are ongoing across western New York and eastern Canada, and the Storm Prediction Center is watching these storms closely and may issue a severe thunderstorm watch. Regardless of a watch being issued or not, these storms have the potential to pack a punch. The sun is also out across the region now, just adding fuel for these storms. Wind damage and hail are the main threats, though I am concerned with flash flooding. Most places have already picked up 0.5-1.5" of rain during the past 48 hours, and more heavy rain could cause some problems. Be safe: Never drive through a flooded roadway!

Storms will continue to rumble through the first part of the night before the cold front responsible for all this moves in with drier air. Stay tuned for any watches and a heads-up to any severe storms!

Long Range Outlook: Late July Heat Wave

Besides a day here and there this month, we have escaped the real brutal heat that can roast our area in July. However, there are indications for quite a large and long heat wave coming towards the end of the month. There isn't much doubt that it will happen as opposed to when. Take a look:

As with almost all our hot periods, this heat will start well to our west, baking the Rockies and Planes. The heat can only expand so far north, and once it reaches that threshold, it heads east.

The article that accompanies the diagram to the left from accuweather.com says this "could become the heat wave of the summer for the Midwest and East."

Taking a look at their 15-day forecast, it looks like starting next week, we could be in for a lengthy period of near to above 90 degree heat. More on this as it evolves!

Severe Storms, New Features coming

Another round of severe thunderstorms will be coming to the area later, probably during the late afternoon and early evening hours. There is also some non-weather news, as I have once again been working on improving grotonweather.com. Read on for more!

Another powerful cold front will come through the region later this afternoon and evening. Temperatures ahead of this front will be in the low 90's and humid, providing fuel for the storms. It looks like multiple lines of storms will form during the day. While one of these lines is already forming well to our west along the cold front, it is any one's guess where the other ones will form. If they get going to our west, our chances for severe weather are much higher. If the lines form to our east, I don't think the line along the cold front will retain its severe levels by the time it reaches here, probably after the sun sets. The main severe threat will be wind and hail, though the conditions appear favorable for a brief tornado or two, especially to areas east of I-81. Even though the largest severe threats appear to be west and east of Groton, the situation should be watched and I will updating as needed throughout the day.

School is out! Congratulations to my fellow classmates as we graduate Saturday (which should be an absolutely perfect weather day!) Since school is out, I have time on my hands. I have been using some of this time to once again upgrade and improve grotonweather.com! I have been conducting a survey (which I would still love for you to take by clicking here) and it quickly became evident that a more regional forecast would be helpful. So, I have been working on how best to include a broader look at the weather. I have it pretty much figured out and just have a few kinks left to work out. While its not ready to be viewed and updated, I did take a screenshot of what it looks like so far. Take a look (click for larger view):

MAJOR SEVERE WEATHER TOMORROW

OK...here is the more in depth forecast for tomorrow, when some major severe weather will come across the region. We have not seen a set-up like this in quite some time and we could be dealing with a bit of a tornado outbreak!

A very powerful storm system is plowing through the Midwest right now, and has already spawned over half a dozen tornadoes, with many more to come. Yesterday, the storm system didn't have as much severe weather because it was actually too strong! The high winds aloft shredded thunderstorms and major severe weather never occurred. However, today and tomorrow, that has changed. After lots of tornadoes, wind and hail tonight, this storm system will have its eyes on the Northeast, specifically Western and Central New York and Pennsylvania. Henry Margusity, the severe weather expert at Accuweather.com, says he is "very concerned" about our area for tomorrow on his blog. He seems particularly concerned with the tornado threat, which is something we don't see much. On his blog, he specifically mentions a number of cities that are under the largest threat, among which he includes Binghamton, Syracuse and Rochester. Here is the link to his blog on Accuweather.com if you care to read/watch what a real expert has to say as opposed to someone who has yet to graduate high-school.

Here is how tomorrow should shape up. The morning will be windy and sunny. After lows in the mid 60's, this sun and wind will only help boost our temperatures. Tomorrow could also end up being the hottest day so far this year, getting well into the 90's. Along with the heat, there will be plenty of humidity in place, so tomorrow will be a very nasty, muggy, hot day. In fact, heavy exercise outside probably isn't a good idea any time after noon. All this hot, moist air will be doing battle with cold air aloft, creating a lot of lift and instability. This will lead to the formation of towering thunderclouds. With strong winds aloft from the northwest and gusty winds from the south and southwest in the low and mid levels, everything is prime for these storms to rotate and produce tornadoes. Large hail and damaging winds are also possible. These storms will fire up in the afternoon and continue through the day. A more solidified line should move through later, with the main threat being wind damage with that. Overall, this has potential to be a tornado outbreak like we haven't seen in nearly a decade. Back in the late 90's, I remember a situation in Late May where there were over 30 tornadoes in New York. This will probably be the largest New York/Pennsylvania tornado outbreak since then.

Ok...so here is some quick review that will be helpful tomorrow. I would imagine we will have a tornado watch issued for us, probably by 1 or 2 PM. A tornado watch means conditions will be favorable for tornadoes, but doesn't mean there are any yet. Now, a means a tornado is either detected or spotted. IF A TORNADO WARNING IS ISSUED, YOU MUST TAKE ACTION RIGHT AWAY! What do you do? Head to the lowest level of the building you are in. Go to an interior room that has no windows. If you are in school or some other such building, head to the hallways and sit against the wall. If you get caught outside and can't get inside, find a ditch and lay in it. In all of these situations, if the tornado hits you, COVER YOUR HEAD to protect it from injury. If you are in a car, get inside a building or find a ditch. DO NOT HIDE UNDER AN OVERPASS. Overpasses actually act as a wind tunnel and strengthen the winds.

Tomorrow during the day, I will post updates as much as I can to keep you ahead of the storm. Keep checking the grotonweather homepage and pay attention to the watches and warnings that are issued. And most of all, stay safe!

Seems like summer!

A busy blog post for sure, all of it having to do with things more typical of the summer than early May! From fires to heat, severe storms to hurricanes, its being talked about:

Fires:
If you have noticed, about a week or so ago I added a "Fire Threat" section to the thunderstorm forecast (for lack of a better place for it). I have been using this as a guide to how likely accidental brush fires are to occur based on a combination of recent rainfall, winds, humidity, and temperature. Lately, all things have been aligned for a "moderate" to "high" risk of fires. This threat became reality yesterday in Syracuse, when sparks from a welder's torch started a small brush fire. When the threat is high, extra caution must be used. One of the bigger risks is actually from people throwing cigarette butts without thinking. As is evident by yesterday's brush fire in Syracuse, when the threat is elevated, it doesn't take much to get a fire going!

Heat:
After hitting 86 yesterday, I thought about maybe putting "near 90" for today's forecast, but thought I might be jumping the gun a bit too much. Since 2003 (when I started recording weather data), it has hit 90 in May only twice. Both times were last year, on the 30th and 31st. However, that record has now been broken. Just after 3PM, I got to 90 degrees at my house, topping out at 90.3! You can see my weather software above (click for a larger image). The high temperature is displayed about half way down on the left panel!


Severe Storm Threat:
There is a bit of a threat for severe storms Thursday afternoon as a disturbance aloft moves through. While widespread severe weather isn't anticipated....nor did it occur today over the Midwest....I do think a few of tomorrow's storms may become severe, with hail and gusty winds being the threat. I would anticipate between 2 and 10 severe weather reports, mostly wind, stretching from Western New York, into Central New York and Northern Pennsylvania and over to about Albany. East of that, there may be some additional severe weather.

Subtropical Storm Andrea:
The 2007 Atlantic Hurricane season got an early start today...or did it? The season officially starts June 1st. Today, a low pressure system was classified "subtropical" and was given the name "Andrea." First off, a subtropical low is basically a hybrid: its got some tropical characteristics, and some non-tropical characteristics. (If you want more details, that would make a great "Ask Drew" question for that section of my website (which isn't built yet...)). In years past, these systems did not receive names. However, during the past few years, they have been given names. So, in a way, the Hurricane Season is off to a running start....but in ways, nothing has yet happened.