Arctic Outbreak?

We all knew it was probably only a matter of time before the weather finally turned more winter like. We got a taste of winter yesterday with some lake effect snow, strong winds, and temperatures in the 20s. While we have been warm lately, 500 miles to the north has been frigid. The chill yesterday and, to some extent, today, is just a small piece of that cold pool.

A much bigger piece will be breaking off next week. It will easily be the coldest air so far this season, with highs Tuesday and probably Wednesday staying in the teens. There will be wind. There will be snow. But will this be an 'arctic outbreak'?

There is no set definition for an arctic outbreak, so the use of the term is up to the discretion of the forecaster. It seems to me, however, that 'arctic outbreak' should be a term reserved for record setting or dangerous cold. It is a strong term that grabs people's attention. I do not think it should be overused.

Does the combination of high temperatures in the teens, gusty winds and lake effect snow meet these qualifications?  I am honestly on the fence.

On the one hand, it seems to me that highs in the teens are not all that impressive, given our climatology and the time of the year. Some lake effect snow and wind? That is just normal winter weather here.

Yet, on the other hand, this has not been a typical winter. We have only one high temperature under 30º (on the 24th...the high yesterday was actually 40, albeit that was at midnight). Snow has been scarce to non-existent. Being suddenly thrust into mid-winter weather may catch some off guard and create dangerous conditions.

In the end though, I think I would hesitate to use the words 'arctic outbreak' in my forecasts for the coming cold snap. I believe that the public should be aware that the pattern is changing and, at least for a few days, winter will be here in full.

But I do not want to sensationalize things and blow them out of proportion. This event, after all, is still nearly a week away. I've seen many extreme temperature events forecast this far out, only to have the models gradually and consistently modify temperatures back towards more normal temperatures.

I want to hear what you think though. Join the discussion and post what your definition of an arctic outbreak would be on Facebook by clicking here.

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.

Was Irene Really a Bust?

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

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

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

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

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

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

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

Down Time

Just a quick administrative note:

Each summer, I take a couple weeks off from intensive forecasting. This gives me a chance to do some other projects, recharge, and, usually, get some new ideas. As such, this summer I will not be updating the website from June 29 (Wednesday) through July 16th (or so).

Grotonweather.com will not be devoid of updated weather information though! Traditionally, I have many links and graphics from the National Weather Service and other trustworthy weather sources that have up-to-date information. My tropical weather page also automatically updates with information on any tropical storms or hurricanes that may form. I do this so that you can continue to be safe and informed, even while the site is not fully operating.

I thank you all for your continued support and understanding!

The Grotonweather.com Name...

I believe a bit of an administrative post is in order to follow up on the poll I had on my website over the weekend about the future name of Grotonweather.com.

First off, I would like to thank everyone who took time to take the survey. The information you gave me was a HUGE help in deciding my future course of action! I had a very good turnout on this survey, and there were some surprising results.

The overwhelming majority of you, it seems, really like the name 'grotonweather.com' and did NOT want to see it changed. This is not the results I expected and, in all honesty, I was not sure what to do for a bit. However, it is with great pleasure that I announce to you now that the grotonweather.com name will NOT be changing!

Now, the whole reason for wanting to change names in the first place was to, over the course of the next few years, grow this operation into something even larger. That is by all means still in the works, and I made a couple purchases just before making this post as the first steps in this plan. Details likely will not be coming out on this until the fall...or later...but I wanted to assure you all once more that there are no plans to get rid of the current site or current name.

Thank you all once again for your support and feedback! It is very much appreciated!

No Alert Mode this time...

A potentially significant severe weather outbreak across much of the northeast, including our area is beginning. However, Grotonweather.com will NOT be going into alert mode for this event. As I mentioned in the Alert Mode blog, I take the issuing of Alert Mode very seriously. I only issue them when it seems like widespread, life threatening weather is likely.

Today's event is very close to that criteria, and I cannot say for sure that I will not issue Alert Mode status later in the day. At this point though, I do not think the storms will organize quite fast enough to bring the high risks necessary for an Alert Mode. If this site was for Chenango, Monroe and Otsego counties, I very likely would be going into Alert Mode. The worst of this event, in terms of spatial coverage and intensity, will likely be just to our east.

That being said, storms are already starting to develop in our area and just to the west. These storms will not take long to become severe, and our threats for wind damage and hail remain at a 'MODERATE' level. Winds up to 80mph and two inch hail are not totally out of the question. Stay tuned for updates!

Severe Weather Awareness Week

This week is Severe Weather Awareness Week. In light of the recent severe and tornadic thunderstorms, I think its very important that we realize that dangerous and deadly weather can and does occur in our area. The first step to keeping yourself safe is education. I will be updating this blog each day with links to the National Weather Service pages for each day of Severe Weather Awareness Week.

Monday- Overview
Tuesday- Severe Thunderstorms
Wednesday- Severe Weather Preparedness
Thursday- Tornado Watches & Warnings
Friday- Flood Preparedness
Saturday- Communication of Hazardous Weather Information

Monday's Historic Thunderstorms

Story originally published on Syracuse.com by Drew Montreuil.

I wanted to take a couple moments and point out some pretty amazing things that happened Monday across the eastern half of the nation. A huge severe weather outbreak blasted across the Ohio and Tennessee Valleys and into the southeast. Severe weather was reported from Texas to Florida, northward into Pennsylvania. Even here in Central New York, we had a few strong thunderstorms. Three-quarter inch hail was reported Monday morning near Ithaca and in Norwich. Hail must measure one inch in diameter before it is considered "severe".

While the National Weather Service continues to do surveys of the damage, the number of reports will continue to increase. But here are some numbers that are just mind blowing:

As of 10AM Wednesday, there were 1377 total reports of wind damage, 1"+ hail or tornadoes from Monday. Since 2000, there has not been a single day with this many severe weather reports. Of the nearly 1400 reports, 1245 were damaging wind reports. The squall line responsible for this outbreak did not stop producing severe weather because it died; it simply moved off shore over the Atlantic Ocean. Unfortunately, there were a number of fatalities associated with these storms as tornadoes destroyed homes and trees were downed onto houses. The image above, from the Storm Prediction Center, shows the severe weather reports from Monday's historic outbreak. Blue dots represent wind damage, while red dots are tornado reports and green dots are hail an inch in diameter or greater. Click the image for a larger view.

More spring-like weather will be on the way for the East, including Central New York. Another powerful storm system will form over the Great Plains this weekend and head up into Canada. A cold front will blast across the Midwest, Southeast and Northeast, with more severe weather possible. Currently the Storm Prediction Center is highlighting areas from Minnesota and Wisconsin south to Texas and Louisiana and eastward to Ohio, Kentucky and Tennessee as the highest potential for severe weather. As we get closer to the weekend though, I would not be surprised to see that threat shifted further to the east. Whether or not we get into the thunderstorms once more is still a bit questionable, but at the very least, our temperatures will shoot into the 60s, maybe even near 70 Sunday and Monday.

Spring 2011 Survey

Every year or so, I do a survey on Grotonweather.com. These surveys are extremely useful to me! They help me gauge how I am doing, what I can do better, what new features to add, and what old features should be removed along with other information. I never allow my surveys to go over 10 questions long so that I can keep it short and simple for you.

I would greatly appreciate it if you took a couple minutes and filled out the Spring 2011 Survey. Thank you very much for your time!

CLICK HERE TO TAKE THE SURVEY

What does an "Alert Mode" mean?

Every once in a while, grotonweather.com will go into "Alert Mode" for various weather phenomenon. Flooding, heavy snow and severe thunderstorms are the three most common prompters of an Alert Mode. But what exactly do I mean by this, and how do I determine when to go into Alert Mode. This post will hopefully help you understand this better.

The Alert Mode is reserved for special instances of exceptionally dangerous weather that will impact the lives of those in and around the Grotonweather.com forecast area. The weather during an Alert Mode threatens lives and property. Precautions to stay safe need to be taken during these events. These are among the most significant weather events our area sees, and are accompanied by widespread watches and warnings issued by the National Weather Service. The Alert Mode is meant as another way to highlight the potential dangers.

Obviously, not every significant weather event is worthy of an Alert Mode, and the decision to send Grotonweather.com into Alert Mode is taken very seriously. Only a few Alert Modes are issued each year. A combination of things has to be taken into account when going into Alert Mode:

First, the weather needs to be significant enough to create widespread dangerous conditions. Every severe thunderstorm is dangerous, and even a little freezing rain can cause deadly automobile accidents. However, most of the time, these dangerous weather events are more localized events that most Central New Yorkers are probably used to. For an event to garner an Alert Mode, it has to be above and beyond the "average" bad weather situation.

Secondly, there has to be a good deal of confidence this life threatening situation will occur. Often times, Alert Modes are prompted during an evolving situation. Such is often the case with severe thunderstorms and flash flooding. These situations will also lead to shorter Alert Mode times, as the dangerous weather is often shorter lived. Other situations, including snow and some flood events, may have Alert Modes lasting days due to the prolonged nature of the event. Typically, these types of Alert Modes can be issued further in advance due to a greater certainty of the event occurring. Still, Alert Modes will almost never be issued more than 24 hours prior to the start of an event. Instead, Grotonweather.com will go into Standby to raise awareness of the potential for devastating weather.

When an Alert Mode is issued, pay extra attention to Grotonweather.com and other weather media sources for frequent updates on the dangerous weather. The weather during these situations may rapidly change. It is strongly recommended that you become a follower of Grotonweather.com on Facebook and/or Twitter for these situations, as updates are frequently issued there. (Click here for our Facebook and Twitter pages). Often times (but not always due to other time restraints), special Grotonweather features are available during these times, including Weather Chats, Videos, safety tips and special maps.

The bottom line is this: as a meteorologist, I personally feel a responsibility to keep you informed and safe during severe weather. The absolute worst thing I can imagine is having a weather related fatality under my watch. The Grotonweather.com Alert Mode is meant to help prevent that from ever becoming a reality. If you see an Alert Mode has been issued, stay aware and "keep checking back for updates!"

2/24 PM Forecast Discussion

My apologies for having to post this here. The SUNY Oswego campus network has somehow decided to block all Grotonweather.com traffic from its network. I have managed to update most of the forecast as normal, but things such as the confidence forecast and uploading snow maps are impossible. Hopefully this will be fixed soon....in the mean time, we have a snow storm on our hands!

Forecast Discussion
A rapidly strengthening storm system over Arkansas will lift north and east, crossing across Pennsylvania tomorrow morning. The models are more or less in agreement with one another now, and they all keep the warm air and rain to the south. Despite this, I am still a tiny bit weary of the possibility of rain for Tompkins and southern Cortland County, as the rain/snow line will only be 30-50 miles to the south. I do have enough confidence to go with all snow now though. As I said this morning, since this storm is probably going to end up all snow, we are going to get it good. Below the discussion is the snow map I made for this storm. Most of the Grotonweather.com area is in the 7-14" range. Honestly though, I would not be at all surprised to see 16" or even 18" somewhere in that pink area. The snow will move in after midnight tonight and really become heavy for the morning hours tomorrow. By afternoon, the snow should begin to taper off. However, the winds will be on the increase, blowing all that fresh snow around. Significant blowing and drifting is likely tomorrow. I would likely be going into SNOW ALERT MODE if I had access to my files. Saturday and Sunday will each feature a shot at a few flurries, but nothing significant. Another storm will be in the works for Monday, but this one should remain all rain with the low tracking well to our west.


Storm total snowfall through Friday evening.

The Hype Machine

My good friend, classmate and colleague Evan Duffey posted a wonderful piece on Syracuse.com this morning. He has given me permission to repost it here. There are a lot of excellent points he makes about how big storms get blown way out of proportion through hear-say and media hype. Take a look:

Storm under-performs, public and media hype make it worse

For those of you wondering why you children's classes were canceled, or what happened to the 18"+ of snow you were expecting because your neighbors told you it would happen, I have your answer. The storm grew to massive size and intensity - in a special place I call overexcited media and populace. The storm, while no pushover, is not that epic, and should never have been treated as so.

In talking to fellow Meteorologist and Syracuse.com blogger Andrew Montreuil, he agrees he is upset at how this storm got hyped up.

While the storm will probably leave a decent impact on the area, talk of 18", 2 feet, etc. have been floating around either word of mouth or the internet. My max total event given during the entire even was 14".

Which brings me to a point I would like to bring up. A MAX snowfall accumulation is not what we expect, it's more then what we expect. When a meteorologist puts up a snowfall range, even I put a little extra on that top number just in case the unexpected occurs. Sadly the public takes this number as what they are going to get. For all of you interested in weather, try to remember this when reading forecasts and discussions.

Now to the meat - why did this storm under-perform even Meteorologists predictions for a storm? I hinted at the reason in a comment I made a few days ago, in my first post about the storm. I said "I think the upper limits of snowfall are possible only if warm, dry air doesn't work its way in too far North." This is pretty much what happened.

Radar overnight revealed a large dry slot was working into the storm. Dry-slots are almost always destructive to storms, taking away some of their thermodynamic strength, and obviously precipitation is hard pressed to be found in an area called a dry slot.

Blogger Drew Montreuil was involved in a Q&A session recently, and one of them really brings to light a lot about the forecast and expectations. Here is the quote:

...just in my day today I have overhead people talking about how we are supposed to get 2 feet of snow and such. These are over exaggerations. Often times, forecasts for big storms seem to take a life of their own. People mishear or misread things and, like a massive game of telephone, things get blown out of proportion. Another common mistake I see all the time is people assuming the high end of a snow prediction will be what happens. If there is a forecast for 6-12", but only 5" falls....it really is a decent forecast. But the hype before hand makes it seem like a bust.

To answer the question directly...I could see this "busting" slightly, yes. There are some indications drier air may work in quicker than what was earlier thought. This could bring the snow to an end a bit quicker, and keep us more in the 4-7" range instead of 6-10". Its a developing situation, and one can never be too sure they have the forecast nailed until the event actually happens...

Hopefully your day isn't too upset by the hype and over forecast of this winter storm, and please don't blame meteorologists. We aren't all that wrong.

Just how low did it go?

Original post appeared on Syracuse.com on 1/26/11; posted by Drew Montreuil. This version is edited.

You certainly do not need a meteorologist to tell you that the cold was bone-chilling Monday morning. However, you might be interested to know how cold it actually got across Central New York.

Click the map for a bigger view!

I put together a map of reported low temperatures from around Central New York. Most of these low temperatures were reported to the National Weather Service through co-op spotters. Some of the other readings were recorded on personal weather stations that upload data onto The Weather Underground.

As you can see, the temperatures can vary greatly over a short distance depending on a number of factors, including elevation, proximity to water and urban vs rural settings. A great example of this is Groton's reported -8º. This temperature was taken at a high elevation somewhat near the Elementary School. On cold nights, the coldest air settles in the valleys. Therefore, I would not be surprised if someone sees the map and thinks: "But I saw the bank thermometer Monday morning say -15º!" Down in the valley, it probably did drop below -10º. If anyone does have a lower reading from downtown Groton, I would be very interested in it, so please leave a comment!

For comparison to previous years, we have to look at Syracuse, since climate data from the NWS is only available for Syracuse and Binghamton. You may be interested to know that the -13º was the lowest temperature in the past few years. The lowest temperatures for the past few years in Syracuse are as follows:

• 2010: -9º
  
• 2009: -2º
  
• 2008: -4º
  
• 2007: -9º
  

Data from before 2007 was not available on the National Weather Service's Climate site for Syracuse. I can, however, tell you that the -13º is no where near the record low for Syracuse since observations began at the airport in 1971. That record belongs to February 1979, when it was -26º.

Winter's Fury Unleashed

As posted by Drew Montreuil on Syracuse.com, 1/21/11

Old Man Winter sure is angry these days, and we will not be escaping his wrath over the next week or so. The first fits of his anger are already being felt across much of the northern half of the country. Yet another Nor'easter is striking parts of New England. This storm brought us 3-6" of snow overnight, but parts of Maine will see over a foot.

In the Midwest, the National Weather Service (NWS) issued an 'Extreme Cold Warning' for parts of Minnesota last night. The Extreme Cold Warning is a new warning the NWS is trying out for temperatures lower than -40º. The warning surely verified, as temperatures this morning in International Falls, Minnesota got down to a mind-numbing -46º. Even Rochester, Minnesota, in the southern part of the state, dropped to -20º.

Some of the cold is on the way for us, but Old Man Winter has another shot to throw at us first: another bout of heavy lake effect snow. Schools across northern Cayuga, northern Onondaga and Oswego counties are dismissing early in anticipation of the lake effect blitz.

A huge contributor to heavy lake effect snow in a set-up like today's is whether or not moisture from the Upper Great Lakes is able to feed the Lake Ontario band. Observations from Canada this morning are indicating that the connection is being made, which only will increase the chances of heavy snow.

The lake effect will start up this afternoon and last into tomorrow morning before only gradually weakening and moving northward tomorrow. Some areas across Oswego, Oneida and northern Onondaga counties could see upwards of 2 feet by late tomorrow morning.

If that was not bad enough, the cold temperatures and winds will bring wind chills down to potentially dangerous levels late this afternoon and tonight. Even those not impacted by the lake effect will want to make sure they are properly bundled up against the cold.

This is all just the beginning though, and the next assault from Winter's War comes in Sunday and Monday. The bitter cold air mass that was over Minnesota this morning will work its way over us later this weekend.

High temperatures Sunday and Monday will struggle to reach 10º, and Sunday night will be the coldest night we have seen in a few years. Many areas across Central New York will see the mercury drop to -10º, and some of the outlying areas may even see -20º.

And now, could a grand finale to Old Man Winter's assault be in the works? The latest long range weather models are showing hints of another coastal storm in the works for the middle of next week. If the current model projections hold true, Central New York could be looking at its biggest widespread snow of the season so far. While it is way too early to tell whether or not that will come to pass, it will need to be watched as we head into next week.

On the bright side...at least its not -46º!

Sleet & Freezing Rain- What's the Difference?

As posted on Syracuse.com by Drew Montreuil, 1/18/11

With icy conditions impacting Central New York this morning, meteorologists have been tossing around words such as "sleet" and "freezing rain", but what are the differences between these icy precipitation types?

For my Honor's Program thesis at SUNY Oswego, I have been investigating how the general public interprets weather forecasts, and what terminology is and is not understood. One of the survey questions I used to gather this data directly relates to today's weather.

When asked what is the difference between sleet and freezing rain, my preliminary results show that only 16% correctly understand the difference. If you do not know the difference, do not feel bad- only a little over half of the meteorology majors I surveyed fully understood the difference!

So, just what is the difference? When the water freezes. Sleet typically starts out as a snowflake while it is in the cloud. As it begins to fall, it melts into a rain drop. However, the melting is brief and, before striking the ground, it refreezes. Thus, sleet is simply falling ice pellets.

Freezing rain, on the other hand, does not fall as ice. Like sleet, freezing rain often starts off as a snowflake in the cloud, and then melts as it begins to fall. The difference here is that there is enough warm air in the atmosphere to prevent the rain drop from freezing on its way to the ground. When the rain drop does reach the ground, it freezes, typically within seconds of contact. There is one important condition for this to happen though: the air temperature at the ground must be below freezing.

While both sleet and freezing rain can cause slippery roads, it is the freezing rain that is typically more hazardous. Since sleet is already frozen when it falls, it can be plowed and shoveled with relative ease. The freezing rain forms a coating of ice on roads, cars and power lines, making it much more difficult to remove. A few inches of sleet is not a huge deal, but even just half an inch of freezing rain can bring down trees and power lines and create a very dangerous ice storm.