Was Irene Really a Bust?

In the days leading up to Irene, the media was alive with dire warnings about how bad Irene could be. In the days following the hurricane, the buzz is about how terrible of a job the predictions were. Really? Or, rather, I should say "You've got to be kidding me!?"

If you were expecting a monster storm surge to flood into New York City like in the movie, "The Day After Tomorrow" (left), then of course you will be calling this storm a bust. That is Hollywood and nothing like that was ever predicted. The real storm surge predictions were 4-8 feet. In an area unaccustomed to hurricanes, such a storm surge could catch people unaware and prove to be deadly. It does not take much of a storm surge to be destructive. But never, ever was total destruction of New York City actually forecast. Many areas met this storm surge prediction and it was a good forecast.

The forecasts called for Irene to be a weak hurricane or strong tropical storm as she moved over top of New York City. At 9am EDT on Sunday, the center of Irene moved directly over Central Park- a remarkably accurate positional forecast which should be applauded, since one of the harder things to predict about a hurricane is its future position. When Irene moved over, the winds were at 65 mph- a strong tropical storm, as expected. Additionally, Central Park received nearly 7" of rain. That is nearly double the average amount of rain Central Park gets in August. What more do you people want before this is labeled significant?

If you are still not satisfied, we can chalk New York City up to being spared the worst and, if you really wish to believe so, over-hyped by the media (not the meteorologists). But the miss was pretty much only for there. It is extremely insensitive and just plain wrong to say Irene was a bust.

As of this writing, 2.5 million homes and businesses were still without power, 2-3 days after Irene came through. Roads throughout the Northeast are washed out or impassible due to fallen trees. Homes have been washed away. Entire towns have been flooded or cut off completely. Some towns have lost all their bridges. Some of these bridges that were washed out have been in service for over 150 years. Even part of the New York State Thruway remains closed. If this storm was such a bust...such a run-of-the-mill storm...nothing worse than a nor'easter...then why all the unprecedented destruction?

And that is just the material loss. At least 40 people have died from this "over-hyped bust" of a storm. Any loss of life is tragic. Those 40+ deaths translate to 40+ tragedies. Ask the family members of any of those who lost their lives if Irene was blown out of proportion. Perhaps they would have a different perspective.

The bottom line is this: even large weather systems like Irene have small subtitles that are not understood and certainly not possible to forecast. The geography of an area also plays a significant role in what exactly happens during a storm. Just because New York City was spared destruction does not mean other areas were. Look beyond your own backyard, your own town, even your own part of the state. It is easy to forget the sufferings of other and blast the forecasters for crying wolf. Just because the wolf didn't get you this time doesn't mean that next time you will be so lucky.

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!

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!"

Heavy Rain Update: 4PM

4:40PM UPDATE: FLOOD WARNING ISSUED FOR S.CORTLAND AND TOMPKINS COUNTIES THROUGH 7:15 PM.

Very heavy rain has been falling across the area and will continue to do so for the remainder of the afternoon and into tonight. The regional radar loop is showing the rain tapering a bit to just showers, but not until far Southern Pennsylvania. Even then, there is still some heavy rain...just not as widespread. We very well may only be about half way through this event, and already rainfall totals are getting quite high. Take a look at some of these reports:

Game Farm Road Climate Station, Ithaca: 1.36" through 3PM
Freeville: 1.41" through 3:42 PM
Virgil: 1.54" through 3:42PM
Binghamton Airport: 1.36" through 3PM
Deposit, NY (Deleware County): 2.99" between 7AM-1:22PM

If we double these amounts, most places will be up around 3-4", as expected. There are no flood warnings in the Grotonweather.com forecast area, but most of the counties to our south, east and north are under flood warnings. Most of these flood warnings are for larger rivers in anticipation of this additional rain. No flash flood warnings are in effect yet.

There are actually some more intense areas of rain and wind within the main area of heavy rain. A severe thunderstorm warning was even issued for Broome County a little while ago! I changed the scaling on the radar program I use to make these areas stick out. The brighter the color, the heavier the rain. The heaviest rain seems to be concentrated over the Finger Lakes, with some of those heavier cells moving through Cayuga and Cortland Counties, as indicated by the dark reds and pinks. It is where these cells hit that the greatest chance for rainfall totals over 4" will occur.

As we go into the evening hours, I am anticipating starting to see some flash flooding problems as we start to approach the upper limits of what the ground and streams can handle. I will get the word out about any Flash Flood Warnings as soon as possible. Remember, NEVER drive through a flooded roadway! If you come to a roadway, turn around. There is no telling just how deep the water is. Just 6" of quick moving water can sweep a car away! It is especially dangerous at night, when it is even harder to see flood waters. Anytime you get rainfall of this magnitude in such a short (about 12-18 hours) time span, the runoff can produce dangerous conditions. Please stay safe tonight, and stay tuned to Grotonweather.com for the latest! Do not forget to visit the chat room by clicking the "Open Chat" icon to the right. The Chat will be open through the early evening. Furthermore, make sure you tune in for tomorrow's podcast as we talk about this event!

Note: One of the quickest ways to get updates from Grotonweather.com is on our facebook page! Become a fan now by clicking here!

Are we done YET?

6:45 PM Update: A severe thunderstorm warning is in effect for the very southern most portions of Tompkins and Cortland counties, but the storm is pretty much south of the county lines. Looking upstream, the more impressive thunderstorms should pass well to our west and east as the cold front begins to press through. As a result, I think we are pretty much done with severe weather here in the Grotonweather forecast area. There will likely be a shower or two...maybe even a light thunderstorm...over the next few hours...but the biggest hazard from here on out through tomorrow morning should be some areas of dense fog.

5PM Update: The storms over Ontario County have struggled to organize and are falling apart into just showers.

UPDATE 4:30PM: As I suspected (but a bit quicker I must admit), a healthy looking cell has broken off the lake breeze and is holding itself together nicely over Ontario County with some new development along its southern flank. If it keeps holding together, it should reach Cayuga Lake about 5:15-5:30 before heading into the Grotonweather forecast area between 5:30 and 7pm.

Original 4PM post: The Grotonweather forecast area has been hit hard twice today, with only the northern portions of Cortland County missing out on the active weather (but not by much, as southern Onondaga County has been hammered too!) Numerous severe weather reports have come out of the area, the most notable being trees and powerlines down in Lansing early this afternoon and a recorded wind gust of 55mph in Locke, 1.25" hail in Dryden and 1" hail in Cortland with the second round of storms.

So...are we done yet? For a little while at least. What has been happening is lake breeze fronts from Lake Erie and Ontario have been triggering storms between Rochester and Buffalo. These storms have been sitting and redeveloping over the same area for hours. As the individual cells move away from the lake breeze, they have been tracking southeast across the Finger Lakes, right into our neck of the woods. the last big storm that went through our area stabilized the atmosphere a good deal, and so as the cells break off of the lake breeze, they have started to quickly die out. I tend to doubt this will remain the case though. The sun is out and already working to destabilize the area once again. Eventually, I believe that another storm will have enough fuel to head down towards us once again, probably in the 1-3 hour time frame. After that, the lake breeze will start to die out. However, the cold front still has to come through and encounter a still unstable airmass across Western New York. more storms may fire up along that as it moves east...especially if it does so while the lake breeze is still adding extra lift to the atmosphere.

Bottom line: we may not be done yet...so stay tuned!

1PM Severe Weather Update

2PM Update: SEVERE THUNDERSTORM WARNING FOR S. CAYUGA COUNTY UNTIL 2:45 pm. A severe storm over Ontario county will move into S. Cayuga county over the next 30-60 minutes. I expect the warning to be extended/overlapped as the storm moves into the area. If the storm remains severe (and there is not really any reason for it not to), Groton, Homer and Cortland will have to watch out for this storm between 3-4 pm. Interesting note: All of the Grotonweather forecast area but extreme northeast Tompkins and northern Cortland Counties have been under severe thunderstorm warnings at some point today already! And our watch goes for 6 more hours.

Original 1PM post: Lots going on this afternoon already. A severe storm tore through central Tompkins county last hour. It is looking a bit less organized as it moves into S. Cortland county. I was in Ithaca, on the 11th floor of Bradfield Hall, Cornell as the storm passed. There was rotation with it, and I got some awesome pictures I will post tonight. The storm produced 1" hail in Trumansburg and took out "many" trees and powerlines in Lansing. No other reports yet (as of 1PM).

While all this was going on, the SPC moved us into a moderate risk. This is primarily for the threat of damaging winds. Now, we've already experienced severe weather...but is more on the way? Our watch goes until 8pm, afterall. The answer is yes, our threat still continues. There are more showers and storms forming over western New York back into Canada. The cold front itself stretches from Ontario back into Ohio and Indiana. The air just upstream is very unstable, and the storms we've already had shouldn't have much of an effect on our instability for the middle or latter part of the afternoon.

If you haven't become a fan of Grotonweather on facebook or a follower on Twitter, you will want to do so now! I've been posting up a storm (pun intended) on those two sites all morning with the latest updates and will continue to do so through the day. Also, the Grotonweather Toolbar is a great way to keep your eye on the latest forecast. Download it here. And, as always, the main site/blog will be updated throughout the day to keep you safe!

That's all for now. Keep checking back!

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.

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.

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

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.