What Weather Forecast Information do People Get, Want, Need, Use,

1
What Weather Forecast Information do People Get,
Want, Need, Use, ?

• Julie Demuth and Daniel Nietfeld
• NCAR Societal Impacts Program
• NWS Omaha/Valley WFO

IWT Workshop Using the WASIS Approach January
22, 2009
2
Do you normally get forecasts during the time
periods listed below?

• From 12 a.m. to before 6 a.m.
• From 6 a.m. to before 8 a.m.
• From 8 a.m. to before 11 a.m.
• From 11 a.m. to before 1 p.m.
• From 1 p.m. to before 4 p.m.
• From 4 p.m. to before 7 p.m.
• From 7 p.m. to before 12 a.m.

3
The forecast high temperature for Kansas City
tomorrow is 40ºF.
What do you think the actual high temp will be?

• 40ºF
• 39-41ºF
• 38-42ºF
• 35-45ºF
• 30-50ºF

4
There is a 30 chance for freezing rain
tomorrow.
What are your concerns for a hazardous impact?
5
Outline

• Julie Survey findings about peoples
• sources, perceptions, and uses of weather
  forecast information
• perceptions of, interpretations of, and
  preferences for uncertainty information
• Daniel

What does it all mean?!
6
Julie (NCAR) and Daniel (NWS)

• Julie, the researcher, provides great questions,
  and great answers, and great research findings
• Daniel, the operational guy, takes Julies
  findings and applies them to the real world
• One without the other is only half-effective
  50 effectiveness rarely makes a difference
• Julie and Daniel, partner and learn from each
  other!

7
Julie et al.s survey design and implementation

• Nationwide, controlled-access web survey of U.S.
  public
• Pre-tested during development and implementation
• Respondent population
• is geographically diverse with responses from
  every state
• has similar gender and race distribution to the
  U.S. public
• is slightly older and more educated

N1520 completed responses, but 3.6 of people
say they never use weather forecasts this
analysis based on N1465 responses
8
Screenshot of sources question
There is a science to doing surveys!
9
Weather forecast questions

• From where and how often do people get weather
  forecast information?
• What times of day do people get forecasts?
• For what reasons do people get forecasts?
• What weather forecast parameters are important to
  people?
• For what locations or regions do people get
  forecasts?
• What is peoples willingness to pay for forecasts?

(See Lazo et al. 2009 for all results)
10
How often do you get forecasts from the sources
listed?

• Response options
• Rarely or never
• Once or more a month
• Once a week
• Two or more times a week
• Once a day
• Two or more times a day

11
What does this mean to us ???

• Certainly can NOT assume that, at any given time,
  people know what the latest forecast is
• In rapidly changing weather conditions, the
  forecast may change frequently (5-6 X / day)
• What can we assume? Lowest common denominator
  
  THEY DONT KNOW THE CURRENT FORECAST

12
Mean of forecasts obtained monthly
Local TV
Cable TV
Commercial or public radio
Other webpages
Newspapers
NWS webpages
Friends, family, co-workers, etc.
NOAA Weather Radio
Cell phone, PDA, pager, etc.
Telephone weather info source
0
5
10
15
20
25
30
35
40
N1465
13
What does this mean to us ???

• MOST people do NOT have access to instantaneous
  weather information such as NOAA Weather Radio or
  a pager
• You TV folks play a major role (news flash!)
• Timely internet updates are important
• There are MANY sources of weather information

14
Time forecasts normally received
80
70
60
50
40
30
20
10
0
12a-6a
6a-8a
8a-11a
11a-1p
1p-4p
4p-7p
7p-12a
N1465
15
What does this mean to us ???

• Morning TV Broadcast Meteorologist may play just
  as important of a role as the evening Chief (?)
• 1 pm 4 pm is when people are paying the least
  attention to the weather forecast
• When are watches often issued ?
• When do warnings often begin ?
• 4 pm 7 pm appears to be an accident waiting to
  happen
• 4 pm is a common shift change in NWS and TV
• People are tuning in
• The cap breaks!

16
Use of weather forecasts
Simply knowing what the
weather will be like
Planning how to dress
self or children
Planning weekend activities
Planning travel
Planning yard work or
outdoor house work
Planning social activities
Planning getting to
work or school
Planning job activities
0
20
40
60
80
100
N1465
17
What does this mean to us ???

• The weather matters, and people do check (i.e.,
  the light blue is less frequent than the dark
  blue!)
• A loose, broad conclusion may be that when
  vulnerability is higher, the weather is of higher
  importance (?)
• Children
• Weekend activities (festivals, boating, etc)
• Travel

18
Importance of weather parameters
When precip will occur
Chance of precip
Where precip will occur
Type of precip
High temp
Amount of precip
Chance of amount of precip
Low temp
Wind speed
Humidity levels
Time of day high temp will occur
Time of day low temp will occur
How cloudy it will be
Wind direction
0
20
40
60
80
100
N1465
19
What does this mean to us ???

• Top 4 are precipitation-related
• Connection between precipitation, storms ? the
  high-impact weather that affects people, that has
  societal relevance!
• More emphasis on when and where precip occur?
  Even on PQPF (chance of amount of precip)?
• There is more dark blue than light blue!

20
Forecast uncertainty questions

• How much confidence do people have in different
  types of weather forecasts?
• Do people infer uncertainty into deterministic
  forecasts and, if so, how much?
• How do people interpret a type of uncertainty
  forecast that is already commonly available and
  familiar probability of precipitation forecasts?
• To what extent do people prefer to receive
  deterministic vs. uncertainty-explicit forecasts?
• In what formats do people prefer to receive
  forecast uncertainty information?

(See Morss et al. 2008 for all results)
21
Some severe, uncertainty forecasts
22
Confidence in weather forecasts
1 day
2 day
Forecast Lead Time
3 day
5 day
7-14 day
0
20
40
60
80
100
N1465
23
Day 2 SPC probabilistic outlook
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• HAZARDOUS WEATHER OUTLOOK
• NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT
  HILL MO
• 600 AM CST WED JAN 14 2009
• .DAY ONE...TODAY AND TONIGHT
• AN ARCTIC AIRMASS WILL OVERSPREAD THE REGION
  TODAY. TEMPERATURES
• WILL DROP TO BITTERLY COLD LEVELS BY
  TONIGHT...WITH WIND CHILLS
• REACHING 15 TO 25 BELOW ZERO ALONG AND NORTH OF A
  LINE FROM ATCHISON
• KANSAS TO RICHMOND...MARSHALL AND BOONVILLE.
  LIGHT SNOW OR FLURRIES
• IS ALSO POSSIBLE WITH THE PASSAGE OF THE COLD
  FRONT...HOWEVER LITTLE
• IF ANY ACCUMULATION IS EXPECTED.
• .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH
  TUESDAY
• DAYTIME HIGHS ON THURSDAY WILL RANGE FROM 15 TO
  25 DEGREES BELOW
• AVERAGE. THE ALREADY COLD START WILL HELP PUSH
  THURSDAY NIGHT LOW

• Hazardous Weather
• Outlook
• Two sections
• Day One (detailed)
• Days 2-7 (???)
• (more vague)
• (inferred uncertainty?)

What does this mean to you ?
25
Suppose the forecast high temperature for
tomorrow for your area is 75F.

• What do you think the actual high temperature
  will be?

50
40
30
20
10
0
75F
74-76F
73-77F
70-80F
65-85F
Other
( 1F)
( 2F)
( 5F)
( 10F)
N1465
26
Suppose the forecast says, There is a 60 chance
of rain tomorrow.
What do you think best describes what the
forecast means?
Percent of respondents
 Response option
It will rain tomorrow in 60 of the region.
It will rain tomorrow for 60 of the time.
It will rain on 60 of the days like tomorrow.
60 of weather forecasters believe that it will
rain tomorrow.
I dont know.
Other (please explain)
Technically correct interpretation, according
to how PoP forecasts are verified
N1330
27
Open-ended responses re PoP

• Many reiterate PoP without clarification
• Many describe the chance theyll personally
  experience rain or personal implications for
  action
• Consistent with other studies, majority of people
  dont know technically correct definition of PoP
• but asking people to think about PoP from a
  meteorological perspective may have limited value
  people still have to translate what it means to
  them personally!

28
Definition of SPC probablities

• The probabilities that you see on the graphics
  represent the probability of one or more events
  occurring within 25 miles of any point during the
  outlook period. This definition is used as the
  probability of severe weather at an given point
  is quite small. There is a large amount of
  uncertainty in forecasting severe weather on
  these scales. How many times have you experienced
  a tornado in your neighborhood? For most people,
  the answer is never. Now think of how many times
  severe weather has occurred within 25 miles of
  your location.

Probability of Severe Hail ¾ or larger
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5 Probability of a Tornado

• Is this a relatively high probability to you?
• 5 probability of a tornado within 25 miles of
  where you are!
• Is this a reasonable threat to you ?
• To you as a
• 22 year old college student
• School superintendent ?
• Factory manager ?
• Large event Director ?
• Emergency Manager ?

30
You are watching the local evening news

• The Channel A weather forecaster says the high
  temperature will be 76F tomorrow
• The Channel B weather forecaster says the high
  temperature will be between 74F and 78F
  tomorrow.

Prefer Channel A
(deterministic)
Prefer Channel B
(uncertainty)
Like both channels
Like neither channel
I don't know
0
10
20
30
40
50
N1465
31
All the choices below are the same as a
probability of precipitation of 20.
Do you like the information given this way?
Chance of precipitation is 20 There is a 1 in 5
chance of precipitation The odds are 1 to 4 that
it will rain There is a slight chance of rain
tomorrow
? Percent ? Frequency ? Odds ? Text
Asked this question 3 ways - using PoPs of 20,
50, and 80 with corresponding text descriptions
from NWS
32
Percent of respondents who said yes
100
80
60
40
20
0
Percent
Frequency
Odds
Text
33
Suppose the high temperature tomorrow will
probably be 85ºF. A cold front may move through,
making the high only 70ºF.

• Would you like the forecast given this way?

The high temperature tomorrow
will be 85F
34
Percent of respondents who said yes"
Deterministic 35
Will be 85F
Deterministic only 7
60
0
10
20
30
40
50
Uncertainty 90
Uncertainty only 63
N1465
35
People want to know the possibilities!

• Area Forecast Discussion (AFD)
• Warning Decision Update product
• Severe Wx Outlook discussion
• TV Broadcaster discussing the range of
  possibilities!

36
Warning Decision Update

• ...WARNING DECISION UPDATE...
• ...THIS WARNING DECISION UPDATE CONCERNS
  SOUTHWEST OKLAHOMA...
• LINE/CLUSTER OF CONVECTIVE CELLS NORTHEAST OF
  LAWTON IS VERY LOW TOPPED (20 K FT) AND ARE
  ASSOCIATED WITH REMAINS OF MESOSCALE CONVECTIVE
  VORT MAX (MCV) LEFT OVER FROM STORMS IN WEST
  TEXAS EARLIER. ENVIRONMENT IS SUPPORTIVE OF VERY
  BRIEF FUNNEL CLOUDS OR PERHAPS A WEAK TORNADO...
  BUT DO NOT BELIEVE CONDITIONS WILL SUPPORT WELL
  ORGANIZED MESOCYCLONE TYPE TORNADOES OR OTHER
  FORMS OF SEVERE WEATHER. RECENT RADAR TRENDS
  SUGGEST CELLS ARE BECOMING INCREASINGLY LESS
  ORGANIZED AS THEY MOVE INTO MORE STABLE AIR. WILL
  CONTINUE TO MONITOR TRENDS IN Z/V DATA FROM
  KFDR/KTLX FOR ANY SIGNS CONTRARY TO THIS EXPECTED
  EVOLUTION.
• ANDRA

37
Severe Weather Responses ?

• If we have this much variety amongst routine
  weather forecast information, imagine the variety
  amongst severe weather warning/watch/forecast
  information !!!

38
Discussion questions

• What other questions do we need to explore about
  peoples attitudes and behaviors? On a day-to-day
  basis? During high-impact events?
• This was a first look at members of the public
  How can we tap into the knowledge and experience
  of IWT members?
• Broadcast meteorologists (e.g., focus groups)
• NWS forecasters
• Emergency managers and other public officials

39
Thank you

• Julie Demuth (jdemuth_at_ucar.edu)
• Daniel Nietfeld (dan.nietfeld_at_noaa.gov)
• References
• Morss, R.E., J.L. Demuth, J.K. Lazo, 2008
  Communicating uncertainty in weather forecasts A
  survey of the U.S. public. Wea. Forecasting, 23,
  974-991.
• Lazo, J. K., R.E. Morss, and J.L. Demuth, 2008
  300 billion served Sources, perceptions, uses,
  and values of weather forecasts. Bull. Amer.
  Meteor. Soc., in press.
• Demuth, J.L, B.H. Morrow, J.K. Lazo, 2009
  Providing weather forecast information An
  exploratory study with broadcast meteorologist.
  Bull. Amer. Meteor. Soc., submitted.