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!

Groundhog Day Speculation

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

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

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

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

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

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

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

Morning Storm Update

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



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

3PM Snow Update

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

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



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

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

More Lake Effect Coming!

Lake effect snow watches have been posted for 2/3 of the grotonweather forecast area, so I decided to go with a blog entry tonight instead of a normal update.. In general, I think I will mostly blog-update during this event, which means you will see the blog up when you come to the site until Sunday morning. As always, you can get to the main page by cicking the banner at the top of the page, or by following the 'Homepage' link under 'Grotonweather Pages'. The homepage currently isn't updated, but will be later tonight or tomorrow as well though. To the weather now:

A very weak and moisture starved storm system has been moving across the area today. This storm will turn winds more northerly tonight and then northwesterly for Friday and Saturday. The airmass that is moving in is pretty much perfect for a big lake effect snow event. I can not remember the NWS posting Lake Effect Snow Watches for areas so far away from the Lake, yet Southern Cayuga and Cortland Counties are both under watches. Admittedly, this is another one of those situations I so often talk about where something is issued for Southern Cayugan and Cortland, but really applies for Groton and Northeastern Tompkins County as well. That is why, on the map below, I have shaded the counties under the watch, as well as where I think the best shot for heavy snow is.


The exact location of the band(s), as usual, is a tough forecast. Normally with this kind of set up, there seems to be a heavy band across Northern Cayuga County, stretching right through Syracuse and into Madison County. A second, slightly weak band, likes to set up in Southern Cayuga and Northern Cortland counties, clipping the Groton area. Of course, these bands aren't always in the same position, and 10 miles difference can make the difference between 2" or 12".

My best guess at amounts are this: Someone in the northern half of the pink area will get well over a foot, possibly upwards of 2 feet by Sunday morning. In the southern half of the pink, someone will get a foot.

The weather models I had available to me this afternoon were from early this morning. As more recent models come in, I will try to pin down amounts a bit more. Stay tuned!

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.

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!

What happened...or rather, why it didn't

I've done some thinking and analyzing this morning, and I think I know where I went wrong with my forecasts last night. Lets start by looking at the last radar image I posted.



As you can see by the radar loop from last night, the snow developed mostly over Western Pennsylvania, West Virgina, and Eastern Kentucky, with lake snows further northwest over Ohio, Indiana and Illinois. Now we did and are still getting the lake enhanced snow, but the other area of snow never formed. Why? The answer lies in the two images I made below:





The area where the snow broke out was just west of and along the spine of the Appalachian mountains. These mountains acted as a lifting mechanism. As the winds hit the mountains, they had no where to go but up. Rising air cools, and with all the moisture left over from the storm, condensed into clouds and moderate to heavy snow. This is called upslope snow. Since there is not nearly the elevation gradient over our area as there is to the south, there was not enough lift to cause a secondary outbreak outside of the light lake effect. This just goes to show that there are so many factors that go into forecasting, which is why it is such a tough job.

And just in case you were wondering how much snow fell as a result of the upslope effect last night in the mountains, Accuweather.com meteorologist Jesse Ferrell put together a small list of some totals on his blog, which you can see here.

One other note about this storm. I have had over 800 hits on my website since Monday, including 571 yesterday! I just wanted to thank all of you for using my site and making it well worth my time. I really enjoy this and I am so happy that you are finding it useful! Thank you again!

Now, one final thing for now. For the past month or so, I have been working on a new website with a group of meteorology students here at SUNY Oswego. This site will give weather forecasts in a similar format to grotonweather.com for clusters of 2-5 counties. This will be a great source for specific weather information outside of our area. I am both the chief meteorologist of this new site, along with the forecaster for the Finger Lakes region. I have set this site up so that Tompkins, Cortland and Southern Cayuga are in a cluster. What does this mean for the future of grotonweather.com? No changes! I simply using grotonweather.com for that region, keeping everything the same for you. This new site will be launching this weekend and will have the URL www.empirestateweather.com, so check it out come Saturday!

9:30 PM Storm Update

The heaviest of the precipitation is racing very rapidly into northern New England and the worst part of the storm has ended over our area. However, all that wrap around moisture I was talking about in my last post is sticking around and will continue to keep the light to at times moderate snows around overnight and tomorrow morning. The winds will continue to increase as well and the temperatures will drop overnight as well. This will allow for considerable blowing and drifting tomorrow, so even when it is not snowing or doing so lightly, travel will be difficult.

I am not quite as confident about a snowday now, but I am going to stick with my original forecast and say it will happen. Just because the heavy snow is over doesn't mean the effects of this storm won't continue well into the day tomorrow.




Here is the latest radar. I didn't bother to color-code it because it is a bite easier to see the different intensities of precipitation on the unmodified version. As you can see, all that snow to our southwest is still sitting there despite the storm being well into New England. As the main precipitation shield continues to lift away from our area, I am expecting a similar set up to form over our area; you can already see it happening in Western New York. Generally, only another 1-4" can be expected tonight with a few locally higher amounts. But again, the wind is going to be the more significant feature of this storm here on out.

PS: I am going to try to do one more update tonight before I go to bed, so if you are still up, check back around or just after midnight!

5PM Storm Update

The storm center is tracking across southern Pennsylvania right now and slowly turning northeast. Moderate to heavy snow is continuing over all of Central New York. Below is the latest radar image from weathertap, and there are a few things noteworthy about it.


1: The darkest blues can be seen over Southeast New York. This is a result of the storm tracking even farther south than the models were indicating yesterday. As the storm turns northeast and rides up the coast, the heaviest snows will likely stay to our east as well. Does this mean we won't get anything? By no means because....

2a. Even though the storm center is now in eastern Pennsylvania, there is a large amount of snow on the back side of this storm. The snow over Ohio is mostly a result of moisture that has wrapped around the back side while

2b. The snow further west is tapping into this moisture and added moisture from the Great Lakes. This tells me that there is plenty of moisture well behind the storm and that the lakes are contributing to the snow.

3. The storm itself is starting to take its turn to the north. While the snow has been moving west to east most of the day, its axis is shifting to a more southwest to northeast orientation. Overnight, it will become increasingly north-south, and the little pockets of lighter snow should fill in a bit.

What does this all mean? There is still plenty of storm to go. As the low moves to our east, the snow shield will still be over us. The wrap around moisture will ensure that even when the storm center is well to the northeast, at least light snow should continue for the area through tomorrow. Winds are gradually shifting towards the north, and this will allow Lake Ontario to enhance the snow fall, especially tomorrow. A little over 3" has fallen so far at my house, and while I am still confident of the lower end of my predictions last night, I think it will be hard for anyone to get up to a foot, except down towards the Catskills. As a result, totals look just a tad scaled back now, with a general 7-11" expected by tomorrow at noon.

Chances still look good for a snow day, especially since the winds will continue to pick up overnight and into tomorrow, keeping the snow blowing around right into Thursday.

Repeat Storm? Feb 17, 2006 & Jan 30, 2008

I have been tracking a storm system that will bring a high wind event to the area tomorrow, and the similarities between this storm and the storm responsible for the February 2006 windstorm are striking!

First off, lets go back 2 years and look at what the Feb. 17, 2006 windstorm did around the area: (All pictures taken by me.)


Tree down in my backyard. This photo was featured on News Channel 9 that evening.


Two towering pines down in Cayuga County.


This photo was taken in April 2007. The tree was partially uprooted during the Feb. 2006 windstorm, but continued to grow afterwards. You can see the new, upwards growth, making this the "bent tree".

Some other notable aspects include:
In Rochester, a lady was killed when a tree fell on her car.
Just outside of Union Springs, road signs were blown over.
At the Waterloo Premium Outlets, a stop light was blown right off its wires.
SUNY Oswego closed for the day because the wind was blowing construction materials around.

Needless to say, this was a pretty impressive wind storm. Now, on a much larger scale, the previous day, Feb. 16, 2006 had some impressive weather as well...weather that seems to be repeating itself today:

Let's start with Illinois. I distinctly remember having a substitute teacher 9th period that day, thus getting a study hall period. I remember being very excited because of the extreme weather in Illinois. In the northwest part of the state, there were Winter Storm, if not Blizzard Warnings in effect. A few counties to the south, a tornado watch! Here is what is going on today in Illinois:


You can see there are once again Blizzard Warnings (in red) to the north, while just a few counties south, a tornado watch is in effect. Now by the time I grabbed this image, the western edge of the watch had been allowed to expire. However, I re-shaded those areas back in the light yellow with white hatching to show how close the two extremes were.

Now lets look at the Storm Prediction Outlooks for Feb. 16, 2006 and today. Notice how similar they are!

Feb 16, 2006 8AM.....then Today 8AM


Feb 16, 2006 12:30PM.....then Today 12:30PM


Feb 16, 2006 3PM.....then Today 3PM

Obviously the outlooks are not exactly the same...but they are very, very close when talking about 2 events, 2 years apart! One last graphic to look at is the storm reports from that day (top) compared with todays [updated last: 7:15PM] (bottom):


One last note to make brings us back to Central New York. Tompkins county and points south and east had a Wind Advisory issued during the event, while counties north had a High Wind Warning. That is again the case today.

Now I am not saying that the exact same thing will happen tomorrow as did in Feb. 2006. I just thought the similarities were very interesting and I thought it would be a fun post to make! Hope you enjoyed it!

So it begins!

The snow has started to fall here ever so lightly, but it is just the start of things to come. Despite most other people still insisting on sleet mixing in, I am sticking to my guns and saying this will not happen. So far, it looks like conditions are starting to favor the all snow forecast.

Temperatures at the surface are in the 30's all the way into North Carolina. Another interesting thing going on in the Carolinas is the winds and pressures are starting to indicate the development of the coastal storm. This is happening way faster than the models projected. As a result, the low to the west of the Appalachian Mountains will not be as strong or make it as far north as the models show. This will in turn mean the warm air won't get in here...not that it would have an easy time doing so since the cold air is so entrenched anyways.

Another thing about the models and cold air is showing up over Ohio. The models had temperatures there in the upper 30's and low 40's...but instead, temperatures have stuck near or just above freezing. So the models are too warm as well, which also translates to a lower chance of sleet here.

All in all the models have not been handling this well so I have pretty much thrown out the recent runs and my thinking from the previous days has not changed. The only thing I would change on my snowmap from last night would be to extend the 12-18" line to include more of Western New York and maybe up the 18" to 20" or even 24". Other than that, everything looks good locally.

Now, as you wake up tomorrow, there will likely already be at least 3-6" of new snow. As the day goes on, the snow will become very heavy and the winds will pick up as well. This will make travel very, very dangerous, so if you don't have to go out tomorrow, stay home. This will continue into tomorrow night before tapering off sometime after midnight.

Storm Potential Heads-Up

This storm is still 4 or 5 days out, but its time to at least start talking about the potential. A large storm system is forecast to develop in the Southern Planes and head northeast this weekend. With very cold air in place across the entire northern tier of the nation, someone is going to get a lot of snow out of this. There are two scenarios that seem possible with this weekend's storm:

The first has the storm plowing into the Great Lakes, bringing possible blizzard conditions to the Western Great Lakes, well away from us. This scenario would spare us heavy snow, though we would still likely get snow and maybe sleet and freezing rain.

The second scenario has the storm coming towards the Great Lakes like scenario 1, but then transferring energy to a second, coastal storm. This would place the heavy snow somewhere much closer by, if not right over Central New York Sunday and Monday.

My gut likes scenario 2...some of the more common models favor scenario 1. As a result, there is tons of uncertainty, so stay tuned as things iron out!