Monday, August 10, 2009

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.

Saturday, July 11, 2009


Northern Tompkins County, and then probably Cortland County, is in for a doozey of a storm. There is a ton of lightning with this one, and hail and strong winds are possible as well. Flash flooding is also a concern with the heavy rain. Take cover now!

Evening Severe Threat

The severe threat is continuing across the area, even though our watch has been canceled and the first round has moved well off to the east. In fact, the SPC is watching a large area of New York and Pennsylvania for a potential watch...and this time, it could be a tornado watch. Right now, most storms are over Pennsylvania. There have been 2 tornado reports down there, and there is another tornado warning out right now. None of those storms will effect us though. However, there is a severe thunderstorm cluster southeast of Buffalo, with additional storms over Lake Erie and north of Lake Ontario. Even though the daytime heating is over, the conditions in the atmosphere are such that the amount of instability will possibly even increase as the evening goes on.

Stay update should come by 9pm. Check to see if a watch has been issued for the area.

Severe Thunderstorm Watch #570

A severe thunderstorm watch has been issued for all of Western and Central New York until 6pm. The main threat the SPC is outlining is damaging winds. Here are the complete risks from the watch:

Probability of 2 or more tornadoes

Low (20%)

Probability of 1 or more strong (F2-F5) tornadoes

Low (5%)

Probability of 10 or more severe wind events

Mod (40%)

Probability of 1 or more wind events > 65 knots

Mod (30%)

Probability of 10 or more severe hail events

Low (20%)

Probability of 1 or more hailstones > 2 inches

Low (10%)

Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events

High (70%)

And the counties in the watch:

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 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, July 10, 2009

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!

Thursday, June 25, 2009


A large cell with the capability of producing hail and damaging winds is about to move into Tompkins County. Lansing and Dryden look like they will take the brunt of this one. There is another cell to its northwest that could come towards Groton, Cortland and Moravia in the next hour or two. Stay tuned.

4:45 UPDATE:
that cell I mentioned to the northwest has gone severe as well. The radar below is an updated image.

Tuesday, June 09, 2009

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.

Saturday, May 16, 2009


As the first storm begins to move into Cortland County after putting down 3/4" hail in King Ferry, a new batch of storms has prompted a warning for Tompkins County and points west. As of now, the worst of this storm looks to be heading along Route 13 and points south, arriving in Ithaca roughly at 4:30, and Dryden about 4:45. As you can see on the radar, this storm is bulging eastward in the middle. That is a classic bow echo signature, which is indicative of some very strong winds. Those in Ithaca and Dryden will want to rush to bring in lawn furniture and anything else that can blow around!


I have been tracking a storm that now has a Severe Thunderstorm Warning for Southern Cayuga and Northern Tompkins and Cortland Counties. Here is the radar at 3:09 PM.

This storm likely has damaging winds and hail with it. Also, there is some rotation in this, which indicates more that it is a healthy, dangerous storm than a chance for a tornado. Please let me know if you have wind damage/hail! Take pictures if possible!

Saturday, May 09, 2009

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:
Probability of 2 or more tornadoes

Low (20%)

Probability of 1 or more strong (F2-F5) tornadoes

Low (5%)

Probability of 10 or more severe wind events

Mod (60%)

Probability of 1 or more wind events > 65 knots

Mod (30%)

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

Wednesday, April 01, 2009

Thursday Weather Update

Based on the number of hits on the site today, it appears this storm has generated a nice little bit of hype! Here is what it is looking like based on the latest runs of the models that I have available:

~A cold front came through earlier today and is currently over New England

~The front stretches back into the South, where low pressure will develop and strengthen, leading to an outbreak of severe weather.

~Central New York will see high pressure, with lots of sun shine and highs in the low to mid 60s.

~Yep...that's right, it was an April Fools joke. :) No storm tomorrow!

~Feel free to leave comments and yell at me for pulling your leg, and enjoy the early spring weather tomorrow!

Click here for your real 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!

Tuesday, March 10, 2009

Flooding Concerns

Over the past few days, a couple of heavy rain events have effected our area. This has left rivers near or just starting to go over their banks and the ground saturated. With another heavy rain event on the way, this is a bit closer look at the potential impacts.

The Advanced Hydrologic Prediction Center puts out river forecasts for the more major rivers. In the Cortland-Southern Cayuga-Tompkins tri-county region, there are three locations that get these forecasts: The Tioughnioga River in Cortland, and Cayuga Lake and Fall Creek in Ithaca. Each location has 4 levels of flooding: action stage, flood stage, moderate stage, and major stage. The action stage is the only one where flooding does not actuall occur. Currently, the two stations in Ithaca are below action stage and are not forecasted to rise to action stage. Our attention then turns to Cortland, where the Tioughnioga is already above flood stage, but is not quite forecasted to get to the moderate stage: (click to enlarge)

Here also is the projected rainfall for Cortland, as forecasted by the NWS: (click to enlarge)

While this rain will certainly swell the Tioughnioga, major flooding problems should be avoided. Now, there are plenty of other small streams and rivers in the area that are swollen. With my resources, I can't tell you which ones will have more flooding problems than others. If you live near a stream, just keep an eye on it, especially tomorrow morning towards the end of the rain. Most importantly though, if you are driving, and you come to a water covered roadway, do not try to drive through it. There is no telling how deep the water is.

Thursday, February 12, 2009

Ithaca Ice Jam Location

Noon Update: The Ice Jam has broken up and Fall Creek is back to its normal level. The Flood Warning has been canceled.

This is a map that the Advanced Hydrologic Prediction Service has for the flood gauge that is reporting the ice jam in Ithaca. If you have travel plans in that area, it would be best to find another route!

Thursday, January 29, 2009

Groundhog Day Speculation

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

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

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

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

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

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

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

Wednesday, January 28, 2009

Not Done Yet!

The snow has ended in Central New York for now. However, we are not done with this storm yet! I do not think this is a classic dry-slotting event, as it is more of a 'bubble' inside the larger precipitation shield instead of a plume. I think this gap is more likely an area between pieces of energy associated with this storm. The warm air trying to come north created the lift needed for our snow overnight and earlier today, but now that energy has worked off to the east. The energy associated with the low remains to our west, so right now, there is not enough lifting force to precipitate. That, plus the periods of sleet and freezing rain this morning, will keep snow totals away from the 12" mark. However, another few inches of snow can be expected as part 2 comes through later this afternoon, putting most places in the 6-10" range. Here is a look at the WeatherTap Radar from 2:15pm.

Wednesday Morning Update

Just a quick update this morning. Sadly I still have classes this morning, so I won't be updating again for a while today.

Heavy snow is overspread the region and the radar shows plenty more to come. As of 8am, my house had 5.2". This will easily put us into the 7-12" range, even though it now looks like there could be some sleet mixing in for a time this afternoon. I still like the 7-12" prediction for most of the area.

The snow will continue through the afternoon and early evening before tapering off. Lake enhancement will hold the snow around after the storm moves off, giving some areas an extra couple of inches.

Weathertap National Radar:

Tuesday, January 27, 2009

Wednesday's Storm

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

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

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

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