Public Information Statement
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NOUS41 KWBC 201830

Service Change Notice 15-26
National Weather Service Headquarters Washington DC
230 PM EDT Mon Apr 20 2015

To:       Subscribers:
          - Family of Services
          - NOAA Weather Wire Service
          - Emergency Managers Weather Information Network
          - NOAAPORT
          Other NWS partners and employees

From:     Eli Jacks
          Acting Chief, Forecast Services Division

Subject:  Operational Implementation of Changes to "Forecast at a
          Glance Icons" on NWS Point Forecast Pages effective
          July 7, 2015

Effective July 7, 2015, at 1400 Coordinated Universal Time (UTC),
NWS will implement changes to the icons depicted on all of its
Point Forecast pages. An example of a current Point Forecast page
for Leesburg, VA, is below:

NWS is making these changes based on analysis of 6,700 comments
collected following issuance of a Public Information Notice on
February 27, 2014.  Also, many of these changes are based on the
results of a research project led by the National Center for
Atmospheric Research (Demuth, Lazo, & Morss, 2012; Demuth,
Morss, Lazo, & Hilderbrand, 2013).

Specifically, the following changes will be made:

1) We will use a new set of icon images, designed to be more
visually discernible and specific. These new icons are depicted
side-by-side with the current icons at:

2) Currently, we show only one icon to cover each of nine, 12-
hour periods out to 4.5 days. Under the new approach, icons will
cover either 12-hour periods or dual, 6-hour periods when there
are rapid changes in the weather.  Examples of such rapid changes
during 12-hour periods may include cases when morning rain gives
way to afternoon sunshine or when precipitation changes from rain
to snow overnight.

The four, 6-hour periods for possible use will start at 6 am,
noon, 6 pm and midnight, all adjusted to local time. When dual
icons are used within any given 12-hour period, the transition
between them will be indicated by a vertical line.

3) When used, the dual icons will also feature new text phrases
beneath them to concisely describe expected changes in the
weather. To support this change, we will also adjust some of the
phrases used beneath all 12-hour and dual icons. The link below
provides a table depicting current phrases side-by-side with the
new phrasing:

The link below offers examples of how the new dual icons, new
text phrases and vertical lines will appear:

4) When Watches, Warning and Advisories (WWA) are in effect, we
will add color blocks around the icons to depict how long they
will be in effect. Specifically, we will add yellow blocks for
"Watches," red blocks for "Warnings" and orange blocks for
"Advisories."  These color blocks will be applied in two
different ways according to the situation, as follows:

a) When one or more WWAs are in effect "NOW" (i.e., at the time
the user clicks), we will add a new color block as the left-most
icon. In these cases, we will also drop the right-most icon for
4.5 days in advance, and the icon for the period already underway
will be moved to the right one position, becoming the second

b) We will also use color blocks to indicate the full temporal
extent of WWAs in effect out to 4.5 days (4 days if a "NOW" box
is used). The length of the color blocks will match the length of
time the associated WWA(s) is (are) in effect.

In both a) and b), we will add a new capability to allow users to
fully identify the WWA(s) in effect, as well as its (their)
duration. For the "NOW" block, users may click anywhere within
the block to view this information. For all WWAs in effect
"beyond NOW," users may click on the grey information icon
(indicated by a circled, lower case "i") provided above the left-
most icons.

Details on the methodology used for drawing the color blocks are
provided at:

5) When the forecast probability of precipitation changes by at
least 30 percent during any 12-hour period, we will use dual
icons and will also display an arrow between the 6-hour icons
depicting the change in probability. Examples of how the arrows
will be depicted are provided at:

Users can preview the new Point Forecast icons up until
implementation on July 7, 2105.  To access the new icons in real
time, go to any Point Forecast Page and click on the banner at
the top that reads "Preview NWS` New Point Forecast Icons."
Doing so will provide information on how to access another page
that will depict the new icons. The preview site is not
operational so performance may be slow during periods of peak

The NWS continually looks for ways to improve its products and
services. Partners and users are encouraged to provide comments
regarding the new Point Forecast icons.

For more information or to provide comments, please contact:

Eli Jacks
NWS Forecast Services Division
Silver Spring, Maryland, 20910

National Service Change Notices are online at:

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