Skip to main content

Can you trust the weatherman?

By Julie Crockett, Special to CNN
February 9, 2013 -- Updated 1846 GMT (0246 HKT)
Sean McCullough, left, plays with his children in Copley Square in Boston on Sunday, February 10, following a powerful blizzard. The storm dumped more than two feet of snow in parts of New England. Sean McCullough, left, plays with his children in Copley Square in Boston on Sunday, February 10, following a powerful blizzard. The storm dumped more than two feet of snow in parts of New England.
HIDE CAPTION
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
Northeast blizzard
`Northeast blizzard
Northeast blizzard
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
>
>>
STORY HIGHLIGHTS
  • A powerful storm is making its way through the Northeast
  • Julie Crockett: Weather forecasts are much more accurate than decades ago
  • It's nearly impossible to accurately model strong weather systems, she says
  • Crockett: The dynamics of the atmosphere is complex; meteorologists have a tough job

Editor's note: Julie Crockett is an assistant professor of mechanical engineering at Brigham Young University.

(CNN) -- A powerful storm is making its way through the northeastern U.S., expected to dump 2 feet of snow or more in some areas.

This weekend will be another test of how accurate those forecasts are.

Weather forecasts are much more accurate today than decades ago, but they are still not perfect. There are two big hurdles to overcome. One is creating accurate mathematical descriptions of the dynamics of the atmosphere. Two is increasing the resolution of the weather model.

Julie Crockett
Julie Crockett

There are many features of the atmosphere that interact in complex ways. For example, the microphysics of clouds is very hard to describe mathematically, and varies for different types of clouds. There are internal gravity waves, which propagate continuously through the atmosphere with significant energy and have the capability of driving, or slowing, strong winds.

The atmosphere includes general circulations that are affected by each other, and by the dynamics of the ocean and rotation of the earth. Depending on the temperature, pressure and humidity of the air, clouds will form and eventually result in rain. Any anomaly can change the entire system. (Just think of the Butterfly Effect, in which a small change such as a butterfly flapping its wings can affect something bigger, like a bird flying by, which can affect something even bigger, like an airplane, until a storm is formed.) Once we find that anomaly, we can track it because we know how the surrounding circulations can affect it.

By the numbers: Northeast blizzard

Become a fan of CNNOpinion
Stay up to date on the latest opinion, analysis and conversations through social media. Join us at Facebook/CNNOpinion and follow us @CNNOpinion on Twitter. We welcome your ideas and comments.



We predict the weather by putting all the observations we have on winds, temperatures, pressures and other variables into a mathematical model that estimates how these systems will interact. Unfortunately, the earth's circumference at the equator is almost 25,000 miles, so when we try to model the entire earth, and go up into the mesosphere (about 25 to 50 miles above the earth) the picture gets fuzzier.

Meteorologists can tell you, about five days out, with fair certainty what the weather will be like in your city or town. But it's nearly impossible to accurately model strong weather systems such as big storms or hurricanes, which include various cloud systems.

In 2011, some residents in Staten Island, New York, evacuated from their homes before Hurricane Irene approached, but Irene took another path and the evacuation turned out to be unnecessary. The mathematical model wasn't wrong, but it couldn't know with absolute certainty the pathway of Irene.

In 2010, a big winter storm was predicted for Utah. Many schools in the state canceled classes. The storm turned out not to be not so bad. This may be partly due to the effect of small, unresolved variations in the atmosphere, such as internal waves, that weakened the storm.

Staying safe when the lights go out

Although miscalculations occur, they are not particularly common, especially over the past decade. We have a much better understanding of the dynamics of the atmosphere, more observations from towers, balloons and radar, and faster computers with much more processing speed and memory. Weather forecasting models are continually improving.

Meteorologists are expected to know everything that is happening around the earth and tens of miles into the atmosphere. That's more space than we can even fathom. And all of the systems within that space affect each other.

Think of it this way: A meteorologist's job is equivalent to guessing when a flashmob is going to break out. At the outset, it seems impossible. But if you meet every person in your city, get to know each of their general habits, and keep track of everyone's plans, you could guess when they might break out into song and dance as a group.

We now know more about all of the systems in the atmosphere, how they affect each other and how they interact. There can still be anomalies, like that out-of-towner, but overall we have a pretty good idea what is going to happen and when. And if an anomaly occurs, how it will affect the entire system.

We tease meteorologists about being wrong when they can't predict the weather to the exact detail, but their job is much harder than most people understand. Just try to remember that the next time you have to shovel yourself out of that unexpected extra 6 inches of snow.

Follow us on Twitter @CNNOpinion.

Join us on Facebook/CNNOpinion.

The opinions expressed in this commentary are solely those of Julie Crockett.

ADVERTISEMENT
Part of complete coverage on
August 19, 2014 -- Updated 2203 GMT (0603 HKT)
It used to be billy clubs, fire hoses and snarling German shepherds. Now it's armored personnel carriers and flash-bang grenades, writes Kara Dansky.
August 20, 2014 -- Updated 1727 GMT (0127 HKT)
Maria Haberfeld: People who are unfamiliar with police work can reasonably ask, why was an unarmed man shot so many times, and why was deadly force used at all?
August 18, 2014 -- Updated 2152 GMT (0552 HKT)
Ruben Navarrette notes that this fall, minority students will outnumber white students at America's public schools.
August 19, 2014 -- Updated 2121 GMT (0521 HKT)
Humans have driven to extinction four marine mammal species in modern times. As you read this, we are on the brink of losing the fifth, write three experts.
August 19, 2014 -- Updated 1158 GMT (1958 HKT)
It's been ten days since Michael Brown was killed, and his family is still waiting for information from investigators about what happened to their young man, writes Mel Robbins
August 20, 2014 -- Updated 1723 GMT (0123 HKT)
Sally Kohn says the Ferguson protests reflect broader patterns of racial injustice across the country, from chronic police violence and abuse against black men to the persistent economic and social exclusion of communities of color.
August 18, 2014 -- Updated 1242 GMT (2042 HKT)
The former U.K. prime minister and current U.N. envoy says there are 500 days left to fulfill the Millennium Goals' promise to children.
August 18, 2014 -- Updated 1310 GMT (2110 HKT)
Julian Zelizer says the left mistrusts Clinton but there are ways she can win support from liberals in 2016
August 20, 2014 -- Updated 1738 GMT (0138 HKT)
Peter Bergen says the terror group is a huge threat in Iraq but only a potential one in the U.S.
August 16, 2014 -- Updated 1734 GMT (0134 HKT)
Mark O'Mara says the way cops, media, politicians and protesters have behaved since Michael Brown's shooting shows not all the right people have learned the right lessons
August 17, 2014 -- Updated 1523 GMT (2323 HKT)
Retired Lt. Gen. Mark Hertling says the American military advisers in Iraq are sizing up what needs to be done and recommending accordingly
August 15, 2014 -- Updated 1941 GMT (0341 HKT)
Marc Lamont Hill says the President's comments on the Michael Brown shooting ignored its racial implications
August 15, 2014 -- Updated 2146 GMT (0546 HKT)
Joe Stork says the catastrophe in northern Iraq continues, even though many religious minorities have fled to safety: ISIS forces -- intent on purging them -- still control the area where they lived
August 14, 2014 -- Updated 2226 GMT (0626 HKT)
Tim Lynch says Pentagon's policy of doling out military weapons to police forces is misguided and dangerous.
August 15, 2014 -- Updated 1315 GMT (2115 HKT)
S.E. Cupp says millennials want big ideas and rapid change; she talks to one of their number who serves in Congress
August 14, 2014 -- Updated 2357 GMT (0757 HKT)
Dorothy Brown says the power structure is dominated by whites in a town that is 68% black. Elected officials who sat by silently as chaos erupted after Michael Brown shooting should be voted out of office
August 14, 2014 -- Updated 1149 GMT (1949 HKT)
Bill Schmitz says the media and other adults should never explain suicide as a means of escaping pain. Robin Williams' tragic death offers a chance to educate about prevention
August 15, 2014 -- Updated 1505 GMT (2305 HKT)
Nafees Syed says President Obama should renew the quest to eliminate bias in the criminal justice system
August 14, 2014 -- Updated 2024 GMT (0424 HKT)
Eric Liu says what's unfolded in the Missouri town is a shocking violation of American constitutional rights and should be a wake-up call to all
August 13, 2014 -- Updated 1922 GMT (0322 HKT)
Neal Gabler says Lauren Bacall, a talent in her own right, will be defined by her marriage with the great actor Humphrey Bogart
August 15, 2014 -- Updated 1056 GMT (1856 HKT)
Bob Butler says the arrest of two journalists covering the Ferguson story is alarming
August 13, 2014 -- Updated 2035 GMT (0435 HKT)
Mark O'Mara says we all need to work together to make sure the tension between police and African-Americans doesn't result in more tragedies
August 18, 2014 -- Updated 2006 GMT (0406 HKT)
Pepper Schwartz asks why young women are so entranced with Kardashian, who's putting together a 352-page book of selfies
August 13, 2014 -- Updated 2308 GMT (0708 HKT)
Michael Friedman says depression does not discriminate, cannot be bargained with and shows no mercy.
August 12, 2014 -- Updated 1525 GMT (2325 HKT)
LZ Granderson says we must not surrender to apathy about the injustice faced by African Americans
ADVERTISEMENT