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Category 5 snowstorms

By: Dr. Jeff Masters, 2:40 PM GMT on February 07, 2006

Hurricanes have their Category 1 - 5 rankings on the Saffir-Simpson Scale. Tornadoes are ranked F1 - F5 on the Fujita scale. Now winter storms have a similar ranking system, at least if you live in the Northeastern U.S. urban corridor. The new scale, announced last week at the annual meeting of the American Meteorological Society, is called the NESIS scale, or Northeast Snowfall Impact Scale. The NESIS scale ranks snowstorms that dump at least ten inches of snow on the Northeast U.S., with a number one to five. The five categories are Extreme, Crippling, Major, Significant, and Notable. The NESIS scale differs from the hurricane and tornado ranking scales in that it uses the number of people affected to assign its ranking. Thus, a massive blizzard that whips Massachusetts, New Hampshire, and Maine with hurricane-force winds and three feet of snow--but affects no other portions of the country--would receive a Category 1 ranking on the NESIS scale, since it only affects a small number of people. The same storm tracking up the East Coast and affecting 65 million people would receive a NESIS ranking of five. There have been only two Category 5 snowstorms to hit the Northeast U.S. the past 50 years--the blizzard of March 13, 1993, and the blizzard of January 7, 1996 (Table 2). According to the scale's creators, the scale can help the emergency managers and the public make appropriate decisions to protect lives and property, assist with evaluatation of building codes, and provide a historical perspective. The scale was developed specifically for the Northeast U.S. because of the great impact winter storms there have on the U.S. economy and transportation system.



It remains to be seen if the NESIS scale will catch on and prove useful. For me, a storm ranking scale makes sense, but trying to forecast if a northeast snowstorm will be a Category 2 or 4 will be difficult, since I'll have to keep in my head a map of the Northeast population, and try and integrate in my head what total area is likely to be covered by how much snow. This is a lot harder than looking at the wind speed and assigning a category, like is done with hurricanes. Thus, I expect it will be some time before the NESIS scale catches on, but it eventually probably will as people become used to it. There are currently no plans to extend the scale to other parts of the world.

So far this winter, there haven't been many winter storms worthy of a ranking on the NESIS scale. The snowstorm of December 9, 2005, which dumped more than a foot of snow in the Boston area, was probably a NESIS Category 2 storm. The long range winter outlook doesn't show any major Northeast snowstorms in the offing for the next week, just plenty of seasonable cold air.

Jeff Masters
Have fun digging
Have fun digging
This is someone trying to dig their car out with a shovel, which daa TAKES A LONG TIME! they are probably still digging but oh well.

Winter Weather

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

cat 5 snow storm cool
Ah the perfect storm a catagory 5 hurricane, unleashes a F5 toronodo in the middle of a catagory 5 snowstorm (LOL).
Dr Masters, speaking as one who lives in the Northeast corridor, I think it's a great idea. And I remember far too many of the storms that were listed above lol.
Dr Masters, you might object that it is difficult to forecast whether a given winter strom will be category 2 or 4 etc, but believe me, that difficulty has always existed, and this classification scheme just highlights it.

It has always been difficult to forecast this because the severity and snowfall amount for these storms depends on how far offshore they track, and a very small difference in the track either way can make a huge difference. It seems much harder than forecasting the track of a hurricane. If a lot of moisture is involved, a small difference in the track could mean the difference between a huge snow dump or just heavy rain.

Local weather forecasters here have struggled with this forever. The tools don't seem to exist yet for predict the track and speed of these storms with the extremely high degree of precision that is required. So it is little better than a crap shoot.

...........GLOBAL FREEZING


Scientist predicts 'mini Ice Age'

ST. PETERSBURG, Russia, Feb. 7 (UPI) -- A Russian astronomer has predicted that Earth will experience a "mini Ice Age" in the middle of this century, caused by low solar activity.

Khabibullo Abdusamatov of the Pulkovo Astronomic Observatory in St. Petersburg said Monday that temperatures will begin falling six or seven years from now, when global warming caused by increased solar activity in the 20th century reaches its peak, RIA Novosti reported.

The coldest period will occur 15 to 20 years after a major solar output decline between 2035 and 2045, Abdusamatov said.

Dramatic changes in the earth's surface temperatures are an ordinary phenomenon, not an anomaly, he said, and result from variations in the sun's energy output and ultraviolet radiation.

The Northern Hemisphere's most recent cool-down period occurred between 1645 and 1705. The resulting period, known as the Little Ice Age, left canals in the Netherlands frozen solid and forced people in Greenland to abandon their houses to glaciers, the scientist said.


I still DO NOT like the idea of putting Population in this equation because it makes it Not "Pure"

Paul told me though that he is doing many storms withOut the population factor - he also said from what he's done '96 and '93 are SO FAR ahead of any other storm.

What's funny is that everyone thinks this came out Just last week but he made it in 2003.

I Also just got one of the OTHER Snowstorm Ranking Reports by Dr. Zielinski of the University of Maine and I'm currently reading it (I'll have a report on this one, because there is something that he puts in His Ranking system that I really like)
I can kind of see your point, because population can shift, and the East Coast has lost population to other parts of the couuntry over the last few decades, so it might make long-term comparisons problematic.

But I really only care about what's the next storm gonna do anyway. Using population does still give a good sense of the impact.

But I'm looking forward to hearing from you about the other storm-ranking scheme.
As usual, the forecasters have seen fit to ignore the Midwest. The Northeast - Midwest blog rarely makes mention of our area..... I live in Waukesha, WI and commute to Chicago IL 2 to 3 days per week. Our weather in the winter determines whether I drive down. We also get major snowstorms. The one 1/20 - 1/21 kept me from having my birthday celebration on schedule. There were areas somewhat north of Chicago that got 14.5" of heavy snow.
> Thus, a massive blizzard that whips Massachusetts, New Hampshire, and Maine with hurricane-force winds and three feet of snow--but affects no other portions of the country--would receive a Category 1 ranking on the NESIS scale, since it only affects a small number of people. The same storm tracking up the East Coast and affecting 65 million people would receive a NESIS ranking of five.

This seems rather silly. So the people in New Hampshire hear that the storm is going to be Category 1, so they think to themselves, ah, this won't be too bad, and get caught out on the road in very dengerous conditions. The scale as described does not seem to be very usefull at all of showing the local severity of where the storm will impact, just big picture effect which is more useful for insurance companies and governments than it is for the people in the direct path of the storm.
I been waiting for another Cat 5 Snowstorm but first
we need to find this guy.

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12. dcw
Storm near the Azores isn't looking very tropical...but it's plenty healthy.
I dont like that scale at all. I agree with you kerneld. For a scale to be useful to the general public, it has to show the effects of the storm at one location. The NESIS scale can be used afterwards for the record books but before hand it will only place non-meteorologically minded people in danger.
Interesting how the top three storms on this scale all took place in a ten-year time span. I had a blast digging out of all three of them... 1996 was particulary amusing, with New Jersey's Governor Whitman shutting down the state, just stopping short of ordering non-essential motorists shot dead on sight.
I dont like the scale much either. I agree with you as well Kernald. I think its important to create the scale in accordance to how the storm COULD effect people, not how its effecting them at that one time. For these storms travel many thousands of miles and cover many different population densities. I think the storms intensity should effect how its rated on the scale, warning people wherever they are that one hell of a storm is on the way.
I'm sorry but what's so wrong about just forecasting in inches of snow and letting people, gov't, etc. prepare from that? Nothing in my mind.

KISS- Keep it simple, stupid.
I agree, Adam. Public scales need to be nice and simple, private ones for the meteorological community can be more complex.
CAN SOMEBODY FIND THE MISSING PERSON!! Mr. Snow Miser
And once again, people put too much focus on the Eastern U.S. Also, the number of people affected shouldn't be factored into the system. When a hurricane hits land, the population isn't factored in now is it?

It's a start, but it will be a long time before I'm satisfied with a snowfall ranking scale.
America's Warmest January ever recorded.

Warmest January Recorded in the US
Yeah, that's been out a while. Some areas in the northern mountain states were 10-15 degrees above normal O_O
I just realized that we'll be seeing a new CBS movie soon :P
I finally found somewhere to get imagery of the low Link
Maybe Paul will have The "Side Equation" (no population included) to become official for people like me who research storms intensity

Although I still like Dr. Zielinski's ideas as well in His System
You all hear that the Moanalua volcano picked up a foot of snow last week? Get out the skis! It snows it Hawaii!
http://image.weather.com/images/maps/pt_BR/tropical/atl_sst_720x486.jpg
You could see a TD ANYTIME Now with That picture
Hey Dr. Masters,

You wrote in your blog:

"Tornadoes are ranked F1 - F5 on the Fujita scale."

I thought I would post a quick correction regarding the aforementioned comment. If I'm not mistaken, tornaodoes are actually ranked from an F0 to F5 classification.

Thanks,
Tony


Please forgive the typo on, "tornaodoes" which should've been, tornadoes.:)
You're dead on right Tony! However, starting next February, it will be EF0-EF5 (see my blog for side link to Enhanced Fujita (EF) Scale).
Hey Dr. Masters,

Oh man, I just realized my own mistake in characterizing the scale, it should be F0 to F6 if I remember correctly?
I keep forgeting about the F6 classification since we've never had one to the best of my knowledge.:)

Thanks,
Tony
i can do it now now i can post photo in to the blog hey hurricanechaser can you see what i can do now i think it is so cool and by the way how is it going
Tony,
The F6 was not designated by Dr. Fujita for use. There never has been nor will there ever be an F6. Check out the EF Scale link for elaboration. :)

Tony
Hey Tony,

Thanks.:) I didn't realize that there was a new update to the scale. I will go check out your blog right now:)

Hey David,

Nice seeing you again as well.:)

I decided I wouldn't be posting in here anymore, but thought I should clarify an obvious unintentional oversight for the rest of the bloggers and Tony you helped educate us as well with the new abbreviations for the scale if I understand them correctly.:) I hope you both have a great night.:)

Your friend,
Tony


Good night Tony!
Hey Tony,

I knew I had read that in my studies awhile back and assumed that it was indeed part of the scale(the F6 ranking)although it is hard to imagine a tornado that could achieve such intensity and size to accomadate that ranking. In other words, thanks for clarifying that for me.:)

Your friend,
Tony


Hey Tony,

That's the great thing about this site, we all help one another stay informed and I have no doubts that you are most likely the foremost expert on here regarding Tornadoes.:) I must say that is a great blog you wrote! I really enjoyed it and thanks again for helping me learn something I wasn't aware of.:) I hope you have a great night.:)

Your friend,
Tony


TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE FEB 07 2006

FARTHER EAST...A LARGE CUT OFF LOW HAS BECOME
BETTER ORGANIZED THIS AFTERNOON. AT THE SFC...A 998 MB LOW IS
LOCATED NEAR 31N26W. A COLD FRONT IS DRAPED FROM THE LOW ALONG
31N22W 26N26W 30N38W. BROKEN CLOUDS AND SCATTERED SHOWERS ARE
SWIRLING AROUND THE LOW WITH THE MOST ORGANIZED RAIN IN THE
EASTERN QUADRANTS FROM 31N-34N BETWEEN 18W-24W. BROKEN CLOUDS
EXTEND WITHIN 100 NM AHEAD OF THE FRONTAL BOUNDARY. GLOBAL
MODELS FORECAST THIS LOW TO DRIFT TO THE EAST AND SLOWLY WEAKEN.
A BROAD UPPER RIDGE LIES E OF 35W AND COVERS THE FAR E ATLC TO
OVER AFRICA. A STRONG JETSTREAM WITH WINDS OF 90 TO 140 KT ARE
ALONG THE N PERIPHERY OF THE RIDGE EXTENDING ALONG
5N40W...21N26W TO ALONG THE AFRICAN COAST TO BEYOND 32N11W. THE
JETSTREAM AND THE DIFFLUENCE W OF THE RIDGE AXIS ARE PROVIDING
SIGNIFICANT UPPER MOISTURE...HELPING TO GENERATE ISOLATED
SHOWERS/FEW TSTMS N OF 11N E OF 20W TO OVER NW AFRICA.

$$
CANGIALOSI

Thanks Tony!
998...it's deepening, and convection is moving towards the center. I'd be stunned if we see a T.S. (its winds are ~ 55kt right now) over 60 waters, but...
How 'bout Subtropical Storm Alberto to start '06?
43. Inyo
I agree with many of you.. a storm rating scale that tries to take into account how many people are impacted is pretty useless. Why even bother with it? Also, how many times is a 'catergory 1' snowstorm going to go somewhere different than forecast and 'intensify' to a catergory 3 or 4 without changing in intensity at all? dumb.

It WOULD be neat to see a classification/naming scheme for winter storms, but it would be difficult to do since they tend to split and do other messy things hurricanes don't generally do
tornadoty that would be cool
Cyclone, you are truly amazing to me. In the face of every scientific fact known to man, and the fact that you are continually mocked, you continue to post. Get off the discussion and go do some modelling!!
image.weather.com/images/sat/atl_oce_sat_600x405.jpg




sorry i am new on posting potot on to the blog
Back from a business trip and it looks like we will have to wait for Alberto until the much anticipated 06 Hurricane Season.
wow KRWZ, nice post, thanks

I think any snow storm rating that doesn't focus strictly on severity of storm (wind, amount, and maybe temp) should not see the light of day.
This daft new NESIS scale may be suitable for insurers, traffic controllers etc. but is inapproriate for public use.
I take exception to the shovel comment, Dr. Masters. I do my 300 foot long driveway by shovel, have developed the clearing of snow into a Zen-like pursuit of fitness of mind and body... ;-)
Somebody please explain something to me. The Fujita scale (at least the original un-enhanced version) only ranks individual tornadoes by the amount of damage they have done. So a tornado with 300mph winds would not be classified as F5 or F4 or even F0 if it never damaged anything or came close. So strictly speaking it is a retroactive scale (as I understand it).

If this is so, then I don't see what the problem is with using a retroactive scale for impact of snowstorms. I take kerneld's point with the example of people in New Hampshire, but that just shows that a retroactive classification system shouldn't be used for predictions. But you could say the same thing about the Fujita scale.

Now the Saffir-Simpson classification for hurricanes is NOT retroactive, it uses (current) wind speed, so it should be possible to predict impact, not just classify it after the fact. But the Fujita scale and the proposed winter storm scale don't seem to work like that.

Am I understanding this correctly? If not, I am sure someone here will set me straight LOL!
Phillyfan~ according to the link above & the statement~ According to the scale's creators, the scale can help the emergency managers and the public make appropriate decisions to protect lives and property, assist with evaluatation of building codes, and provide a historical perspective. & how Dr Master's discussed how it will be tough making forecasts while keeping populations in the back of the head til one gets used to doing it ~ It really doesn't sound retroactive. Their gonna try to forcast the catagory before it hits & with way more lee time than ~heads down, that town, could be a F5 coming your way.

This was taken from the link Master's left~ This scale was developed because of the impact Northeast snowstorms can have on the rest of the country in terms of transportation and economic impact. This isn't good for warning people in the path. This is more in line with the piece in the mission statement concerning helping the economy. Which is all good except, I think, for the confusion.
Thanks Skyepony
Not surprised to see the 1993 Superstorm at the top of that list. It was the most far-reaching weather event of the 20th Century. At its height, the system covered the entire Eastern United States, and affected over 100 million people. I was living in the DC area at the time and I remember that weekend all too well!