Hold the Hype, Please

For the past few days, the models have been very inconsistent with one another, and from run-to-run (meaning the morning version of a model disagrees with the same model's afternoon version which disagrees with the night version and so on). The problem storm is a nor'easter that is expected to develop over the Gulf of Mexico before storming northward on Monday. Some models had been pushing the storm off the east coast, while others bring it further inland. As is always the case with these types of storms, the track is everything.

The evening models last night (Thursday) finally showed some agreement with a more inland track. This had some major implications on the meteorological community: the hype machine was put into full throttle. To understand this, and the forecasts that are gushing out, the public needs to glimpse into the mind of a meteorologist for a moment.

Most of us love storms...it is just part of our nature. Active weather is exciting. Unseasonable weather gets our adrenaline pumping. Average temperatures and sunny weather are, dare I say, boring. So when there is a big storm on the horizon, there is always a temptation to sensationalize it and force our predictions into more of what we want to happen and less what the models actually say will happen. This is called 'wishcasting'.

It is difficult not to wishcast, and it is something I struggled with a lot during the early days of Grotonweather. I easily got caught up in hype and would force situations to what I wanted to happen. I would latch onto little parts of the model that supported my desire, and ignore larger parts that would indicate I was about to make a bad forecast.

So when the models came into some semblance of agreement last night, the floodgates were opened. Many now felt justified in making big predictions-- after all, the models are all agreeing now!!

Hold the hype, please.

This is a nor'easter we are talking about, a proverbial thorn in the side of meteorologists for as long as they have been predicting weather in the Northeast. The models three days out for a nor'easter often do not capture the details that make or break the storm. Sometimes even the models a day out are no good. Consistency is the key. Just because the models yesterday evening agreed does not mean they will not disagree again this morning, afternoon or evening. It would be wise to see a few more runs of consistency before calling for a monster storm.

But now, to the wishcasting.

As I said above, meteorologists love active, out-of-season weather. What is more out of season than a heavy snowstorm in late April? And that is exactly what some meteorologists are calling for over parts of the region. However, given the current models, I feel such a forecast is uncalled for. Could it happen? Sure- history shows it can. I just do not think anyone is justified in making that call yet.

The first problem is the "540 thickness line". Meteorological jargon for sure, but let me explain. One of the (many) equations we have to learn in school related the average temperature of the atmosphere above a given point to the pressure at certain levels in the atmosphere. A warmer atmosphere will cause higher pressures, and thus a "thicker" atmosphere.

There are certain rules of thumb for how "thick" an air column above a point can be before the air is too warm for snow. One of those rules is the 540 line. To keep things simple, it suffices to know that values below 540 are favorable for snow and values above 540 are going to be rain. This rule has a catch though: it works best in the dead of winter. In late fall and early spring, values at or just below 540 probably are going to be rain, or perhaps a rain/snow mix at best. I like to see values closer to 534 before I get excited about snow.

Let us now look at Monday morning at 8am, the time that many meteorologists are posting images of the models for. Surface temperatures will be coldest at this time, with daytime heating kicking in for the afternoon Monday.

Major snow storm? The models don't think so.

As you can see, these three major models all indicate little, if any, snow confined to the far western fringes of the storm. Additionally, temperatures have been unseasonably warm all winter and spring. The ground, therefore, is also unseasonably warm. Late April storms of the past (2007 and 1993 for example) have come following very snowy years where the ground was likely cooler than normal. I have a hard time believing snow would accumulate very easily except perhaps over the highest elevations unless it got very cold (surface temperatures in the 20s).

Models try to directly guess the precipitation type and snowfall amounts, and some will undoubtedly point to those model outputs as their justification. (The NAM model, for example, has 6" of snow in Ithaca on Monday). Those model predictions are basically made by taking the model predictions, putting them through more equations and conditions, and then trying to make a new prediction. They can be useful, but the more processed the model data is, the greater the opportunity for error. The precipitation type and snowfall amounts, especially from the NAM model, I have found to be rather unreliable this spring. A few weeks ago, this same model insisted on bringing Ithaca another storm of 6-12". It rained.

In conclusion, this is what I want the public to take away from this. We don't know what will happen yet. Confidence is low and this system needs to be watched. While I enjoy the loyalty my patrons have to Grotonweather, I encourage them to look at other forecasts, too. I have been wrong before and will be again in the future.

What I want other meteorologists to take from this is as follows: we, as a meteorological community, need to focus more on uncertainty and communicating that in our forecasts. We need to cut the hype and sensationalizing every large storm. There are times when we NEED to really play up a storm- like last weekend's tornado outbreak. There was a lot of justified hype last weekend and it saved lives. This weekend's hype is not justified. Where do we draw that line? It is impossible to say for sure. But I can say it needs to be drawn better than it currently is, or when it does matter, people are not going to listen.

Respite Coming..But so is More Rain

 7:30 PM Update-

Unfortunately, the break in the rain I talked about 90 minutes ago below is filling in already. This means even more rain than I was expecting in the last post. That in turn means more flooding. Certainly not good news at all.

Wednesday- 6PM

For the past few hours, very heavy rain has been falling across our area. Major flooding is going on nearby, with some flooding also occurring within the Grotonweather area. Flash Flood Warnings are widespread across Central New York and Pennsylvania with numerous Flash Flood Emergencies and State of Emergencies in effect for neighboring counties. This will easily end up as the most destructive flood event in the region since the deadly June 2006 flood, which mostly missed the Grotonweather area, and may surpass that in some areas.

For all the bad, there is a little glimmer of good. The current band of heavy rain is quickly lifting to the north. By 7pm, we should be in another respite with just a few showers around. THIS DOES NOT MEAN THE FLOOD THREAT WILL DIMINISH JUST BECAUSE IT IS NOT RAINING. Runoff will continue to inflate streams, which will continue to rise and create major flooding in areas. The flooding just will not be getting rapidly worse.

Until the next batch of rain, that is. Models are indicating yet another batch of heavy rain streaming northward from the Mid-Atlantic. This rain should arrive here well after dark and during the overnight hours, making it particularly dangerous. Flooding dangers at night are enhanced because it is hard to see flood waters and impossible to tell how deep they may be (not that you really can in the day time either).

This is what the HRRR (high-res rapid refresh) model predicts the radar to look like at 11pm tonight. It looks a lot like what the radar has looked like most of the day, meaning more heavy rain will be impacting our area tonight.

If you have to travel tonight: take it slow, DEFINITELY DO NOT ATTEMPT TO CROSS A FLOODED ROADWAY, and be aware that many roads south and east of our area and some roads in our area are closed. For example, every road in Chenango County has been closed. States of Emergency, in addition to Chenango County, are in effect for Broome, Otsego, and Bradfield, PA, to name a couple.

If you live near a creek, stream, river, or drainage area: Chances are you already have an excess amount of water rushing through many times the normal amounts. Additional rain could increase the amount of water attempting to flow through there. Be prepared to have to leave your home at any time, even in the middle of the night. Keep an eye on the water levels as much as you can. If you have a weather radio, keep it on tonight. There are also lots of website that will send updates to your phone...you may want to sign up.

This remains a very dangerous situation, even while the rain lets up for a while. Please, please be safe. Continue to check the Grotonweather website, facebook and twitter pages for updates. Please share this blog with others so that they can stay informed and safe as well.

Growing Flood Concern

 4:30PM Update-

Everything is progressing as I feared and a FLASH FLOOD WARNING has been issued for Tompkins and southern Cayuga Counties. The ENTIRE Grotonweather forecast area is now under FLASH FLOOD WARNINGS. This is going to be a long night for our area.

Wednesday- 2:15PM

So far, the Grotonweather.com tri-county area has more or less been spared of major problems, at least that I am aware of. Our neighbors to the south and east in Tioga, Broome and Chenango counties have not been as fortunate. Massive and widespread flooding has prompted Flash Flood EMERGENCIES for all three counties, with a State of Emergency also in effect for Broome County. Many roads are under water and bridges are in danger of washing out. This is a very dangerous and deadly situation in these areas. Under no circumstances should you be traveling to those areas tonight.

Here is what is really worrying me though...our luck could soon run out. In the image below, you can see a band of very heavy rain moving north through Pennsylvania right towards our area, which is outlined in red. The heavy rain to our east will continue to move to the northeast.

This band of rain extends all the way down past Washington DC and seems to only be increasing in size and intensity. If the flooding that is occurring to our south and east is any indication what a couple more inches of rain will do, our area may be in trouble.

I urge everyone to be extra vigilant this afternoon, evening and overnight. This is one of the most dangerous situations in Grotonweather history, if not for our immediate area, then for our neighbors directly nearby. DO NOT drive or walk in flood waters. If the water is flowing, chances are that you will need to be rescued. If you are told to evacuate, do so. In fact, if you live near a stream that is already full or near...be prepared to leave on a moment's notice. The time to prepare is now.

Please share this post with your friends and family.

Major Flooding Reported

9:45PM UPDATE: The rain in Pennsylvania has still not turned east and is making me very nervous. The rain is as far north as I-80 in Central Pennsylvania. I unfortunately will not be able to update again until after after 12:30am. I will post a quick update at the time though.

The back edge of the rain shield is beginning to move through the Grotonweather tri-county area and will continue to do so over the next hour or so. Rainfall totals are over 3" over most of the area, and radar estimates max out at 4-5" over southern Cortland County. In all honesty though, it appears the radar is under estimating the precipitation, so I would not be surprised if places like Marathon got even more.

As I have been saying, if these rainfall amounts occurred in our area, the ground would not be able to handle it. Unfortunately, that prediction has come true. Here are a couple of the flooding reports I have heard so far, all from Cortland County:

• NO UNNECESSARY TRAVEL IN CORTLAND COUNTY UNTIL FURTHER NOTICE
• Route 11 between Reagen Road and Hoxie Gorge Road is CLOSED due to a mudslide
• Other mudslides have also been reported
• In Homer: The Haights Gulf Bridge is out.
• In McGraw: Roads IMPASSABLE throughout the village
• Red Cross Shelter for evacuees in the gymnasium at the County Office Building

I have not heard of any flood reports in Tompkins or Cayuga Counties, but that does not mean it is not occurring. I cannot stress enough, never drive through flooded roadways!! There are roads underwater in the area. DO NOT attempt to cross the flood waters. Doing so may put your life in jeopardy. If you are told to evacuate your home, do so!

As I stated at the start, the rain is ending. However, this does not mean the flood threat is ending! Runoff will continue to create flood problems into tomorrow. Area rivers are not expected to reach their peak heights until about this time Friday.

There may be some additional rain tonight. What is left of Tropical Storm Nicole is moving up through North Carolina and Virginia currently. The models have consistently kept this rain off to our east tonight. However, the fact that the models were too far east with today's storm, and the fact that the radar from that region looks very much like it did last night (namely a large area of rain seemingly heading right at us) has me a little nervous. I should stress, though, that we are not in the same sort of set up now, and, thankfully, I do see indications in the upper atmosphere that this rain will turn to our east, as the models indicate. If the models were wrong, which I do not think they are, and we were to get another couple inches of rain tonight, it would be disastrous. Again, I do not think this will be the case.

In summary...the rain may be ending, but the flooding will continue into tomorrow. Stay safe!!!!

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!

Into the Moderate Risk

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

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

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

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

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

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

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

Tornado Watch to the south

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


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

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.

3PM Snow Video

NOTE: The watches, warnings and advisory part of the show is already out of date, with a WINTER WEATHER ADVISORY in effect for the entire Grotonweather.com forecast area, and WINTER STORM WARNINGS in the bordering counties south and east. Enjoy the video...leave comments!

Flooding Weather Video

I have decided to try my hand at video blogging for the upcoming flood potential. Let me know what you think!

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.

Late Season Storm

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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!

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!

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.

Dry Slotting

Snow Totals:
10AM- Dusting
11AM- 0.5"
12PM- 1.5"
1PM- 3.2"
2PM- 4.2"
3PM- 4.6"

Post:
Bad news for snow totals, good news for traveling...but the storm's dry slot is going to just hit Groton. It is racing eastward across Southern New York and should be entering Tompkins and Cortland Counties by 3:30. This should more or less end the snow.



Now, the low is forecast to start taking more of a southeasterly track, so I think we will get back into the snow this evening. However, we will be hard pressed to get to 8" I think...let alone a foot. I think 5-9" total would be a good projection for Groton now. Areas just to the north, however, that remain in the snow will stick in that 8-14" range.

Another Friday Snow Storm

Another Friday, another snow storm for Central New York. Unlike last week's storm, this storm is not a nor' easter. It is pretty much moving west to east, so there is no worry about the models having an eastward bias. That makes my life a little easier this time around. I decided to do a snow map after all, even though the entire GrotonWeather forecast area should get the same amount.



As you can see, this will be a big storm, despite its relatively short duration. The snow will being to move in during the morning, before coming heavy by 10 or 11AM. It will really come down hard for a period of 6-8 hours, likely exceeding an inch per hour at times. By the evening, it will quickly taper off to just flurries over night.

I am going to dinner now, but once I get back (by 6:30-7), I will open the chatroom to field questions...and I will likely be there a good part of the night!

Love That East Bias!

I hinted this morning in my forecast discussion that "If it [the storm] really gets its act together, we could end up on the high end of those totals [from last night's snow map]." Well, the storm remains very impressive on satellite and radar. One thing is very evident though. The eastward bias of the models I was talking about is showing up perhaps even more significantly than I thought it would.

When I looked at the models last night, the back edge of the precipitation was roughly from a Pittsburgh, PA to Rochester, NY line. Already though, precipitation is being detected on radar as far west as Cleveland and Buffalo (though it is probably not yet reaching the ground). The low right now is over northern Georgia and is already a good one hundred or so miles further west than it is supposed to be.

The National Weather Service and local media stations have picked up on this finally and have more or less come into agreement with what I was saying yesterday. Tompkins and Cortland Counties are now under WINTER STORM WARNINGS instead of the Advisories that were in effect. Those last until 10AM tomorrow. Since the low will track a little further inland, the precipitation may be a bit heavier and last a bit longer than last night. I also mentioned this morning the possibility of expanding the 6-10" range west. As you can see, I have now done that with this new data.



After school activities have been canceled for many schools in our area. I would say that the chances of a snow day have increased a bit. It is still far from a certainty, but there is certainly cause for hope!

Also, if you haven't heard yet, I have a new feature on the site that I just added this morning. If you look to the black bar on the right side of the page, you will see a link to the 'GrotonWeather Weather Chat.' The text will either say the chat is open, of that it is closed. If it is open, it means I am sitting in the chat room, ready to give you whatever information you want to know about the weather! So, if you see that the room is open, come on in!

Here we go!

Winter Storm Watches have (finally) been posted for the grotonweather.com forecast area! I say finally because, if I had been working at the National Weather Service, I would have issued these watches yesterday. All season long, and going back into last season, the models have shown an eastward biased with storms coming up from the south. This is a large part of why a lot of last winter had a lot of hype about snow storms (myself included), only to have the storms start as snow, then change to ice and/or rain. The actual storm tracks have continuously come further west than the models suggest. So when I saw the models showing snow for Eastern New York and New England yesterday, I thought 'Thats going to hit CNY'....and now, it looks like it will.

The NWS has Winter Storm Warnings up for areas just south and east of us. I again have to say though...they are too far east! Even just a day or so ahead of this event, I do not trust the models to place the heaviest snow properly. So, I am diverging from them and the NWS and, while I haven't checked them, likely the local media as well.

So, what is this all about. An area of low pressure is over the southeast. As I said in this morning's discussion, severe thunderstorms, including torandoes, have been ongoing constantly since yesterday morning. This is indicative of the energy of this storm. As this storm comes up the coast, it will interact with the cold air left over from today's front, with the circulation just pulling more of it in. It will be a classic nor' easter...just not super powerful.

Snow will likely begin to fall in our area sometime in the late afternoon tomorrow and become heavy into the night. This storm will be a pretty quick mover, so that will help in keeping totals down. I also think that, even with the eastward biased, the heaviest snow will stay just east of our area. I haven't had enough time to hammer out a snow map yet, but, on a whim, I am thinking 5-9" is likely for most of Tompkins County and Southern Cayuga County, with perhaps 6-10" over Cortland County.

And now...what you all really want to know....will there be school on Friday? After my epic failing on predicting a snow day last February, I considered not even doing snow days this season...but, due to popular request, I will. Since this storm is coming through at night, I would say there is certainly a chance. Just how much of a chance remains to be seen. You will have to keep checking back to find out!

Next projected update: 10-11:30PM: Snow map!