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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
330 PM EDT FRI JUN 24 1994
TO: NATIONAL WEATHER SERVICE (NWS) OFFICES, WEATHERCASTERS
AND BROADCAST METEOROLOGISTS
FROM: NWS OFFICE OF PUBLIC AFFAIRS
SUBJECT: EXPERIMENTAL ULTRAVIOLET INDEX BEGINNING
JUNE 28, 1994
This message and two additional messages (a one-page fact sheet
and a number of questions and answers) under the same header,
which will immediately follow this message, are meant to provide
some preliminary information to you in advance of a news
conference to be held in Washington, D.C. at 10 a.m. June 28.
TV weathercasters and meteorologists may want to receive a
satellite transmission of a video news release and background
(B-roll) footage. This video package will be available between
2:00 p.m. and 2:30 p.m. on June 28 from the following satellite:
Galaxy 7, Transponder 9, Audio 6.2/6.8.
Some additional materials relating to the Experimental UV Index
contain charts and graphics which cannot be dispatched
electronically. These materials are being sent by U.S. mail to
our list of about 750 weathercasters and meteorologists. A
difficulty in processing some of the contents of this mailing
will likely delay delivery of this package until at least
June 28.
Two additional messages on this topic will follow under this same
header.
END
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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
330 PM EDT FRI JUN 24 1994
TO: NATIONAL WEATHER SERVICE (NWS) OFFICES, WEATHERCASTERS
AND BROADCAST METEOROLOGISTS
FROM: NWS OFFICE OF PUBLIC AFFAIRS
Experimental UV Index
In May, several articles and television news reports appeared
concerning the joint development of an experimental Ultraviolet
Index by the U.S. National Weather Service (NWS) and the U.S.
Environmental Protection Agency (EPA). The following summarizes
the progress of the experimental UV Index and current thinking on
dissemination.
The experimental UV Index is a new product developed by the NWS,
with the support of the EPA and the Centers for Disease Control
and Prevention (CDC). NWS has taken responsibility for the
creation of the product, and the science supporting it. EPA is
responsible for public education and outreach, with assistance
from the CDC.The intent of the program is to enhance public awareness of
the effects of overexposure to the sun's ultraviolet rays, and to
provide the public with actions they can take to reduce harmful
effects of overexposure, which may include skin cancer, cataracts
and immune suppression.
Daily predictions of UV exposure are determined for the noon
hour. Everybody needs to know about effects of UV exposure,
which include the potential for sunburn, skin cancers, aging and
wrinkling of the skin, ocular damage, cataracts and immune
suppression.
Exposure levels are presented below:
Index Value Exposure Level
0 to 2 Minimal
3 to 4 Low
5 to 6 Moderate
7 to 9 High
10+ Very High
The experimental UV Index is a forecast of the next day's
ultraviolet intensity at the earth's surface over the one-hour
period around noon. To derive the UV Index, ozone data from
satellite observations, atmospheric pressure and temperature
forecasts and expected cloudiness are scaled to produce an index
with a range of roughly 0 - 15.
Beginning June 28, 1994, the UV Index is being implemented as an
experimental program, covering a limited number of U.S. cities.
[source: NOAA/EPA 430-F-94-021]
END
NNNN?ZCZC WSHPNSWSH ALL
TTAA00 KWSH DDHHMM
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
330 PM EDT FRI JUN 24 1994
TO: NATIONAL WEATHER SERVICE (NWS) OFFICES, WEATHERCASTERS
AND BROADCAST METEOROLOGISTS
FROM: NWS OFFICE OF PUBLIC AFFAIRS
Experimental UV Index
Qs & As for Meteorologists
This document is intended to help meteorologists answer basic
questions about the experimental UV Index, the new product from
the National Weather Service (NWS). This information may help
you field the many important concerns and questions the public
may have.
Q: What is the experimental UV index?
A: The experimental UV Index adjusts solar radiation by a
number of atmospheric effects to forecast UV exposure levels in
major cities around the country. For the first year, the UV
Index will be available for a subset of cities on an experimental
Q: How do clouds affect predicted levels of UV radiation?
A: The effect of clouds on UV levels depends on the degree of
cloudiness. Although thick overcast will reduce ultraviolet,
thin overcast scattered clouds may not reduce UV levels. As with
any forecast, local variability may change actual levels
experienced. For this reason, a useful rule of thumb to offer
your audience/user is that, whatever the day's prediction, they
should protect themselves against overexposure to sunlight
whenever they can see their shadow when outdoors.
Q: How does the forecast account for altitude?
A: UV levels increase with altitude because there's less
atmosphere to attenuate the radiation. This factor is considered
in the forecast for specific cities. In general, UV levels rise
2% for every 1,000 foot rise in altitude or 1 index unit for
every 4 thousand feet in summer.
Q: How do reflective surfaces affect the predicted index level?
A: Snow, sand and water are all reflective surfaces and will
intensify UV exposure to varying degrees. Grass reflects from
2.5-3%, sand 20-30%, snow and ice 80-90%. Depending on the angle
of reflection, water can reflect up to 100% of rays striking the
surface. Seasonally appropriate messages may help people be
aware that, for example, sand and water at beaches can increase
the reported level considerably.
Q: How much do UV levels vary by season?
A: Seasonal variability can be quite high. Late spring to
summer typically produces the highest UV levels, while in the
early winter, levels are lower.
Q: If I go on vacation in the Bahamas, how much more UV can I
expect to be exposed to?
A: Generally speaking, the closer you are to the equator, the
higher the level of UV you will be exposed to. Because you may
not be used to such high levels, it makes particularly good sense
to cover exposed areas and wear sunglasses. Even during the
winter, you can be badly sunburned at lower latitudes.
Q: What affect does the ozone layer have on reported UV levels?
A: It is well known that atmospheric ozone decreases the amount
of incident UV. The exact impact of ozone depletion, or other
local effects, including haze, aerosols, et cetera, are not
yet fully understood.
[source: NOAA/EPA 430-F-94-020]
END
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