Salisbury, Maryland

To: subscribers:
          -family of services
          -NOAA weather wire service
          -emergency managers weather information network
          other NWS partners... users and employees

From Thomas graziano
          chief... hydrologic services branch

Subject amended to change date: comments sought by
          December 8 2008 on possible unification of
          event-based flood products under the Flood Warning
          /flw/ identifier

Amended to extend due date for comments on the proposal until December 8 2008

NWS is seeking comments by December 8 2008 on a proposal to
unify all event-based hydrologic products under the Flood
Warning /flw/ identifier. If implemented the change would not
occur for three or more years. Advantages to unifying event-
based hydrologic products under a single identifier include:

O simpler configuration - follows the approach used in NWS
winter storm /WSW/ and non-precipitation /npw/ products and
eliminates the confusion caused by the multiple identifiers
used in current flood products.

O provides a new transition capability. For example... it would
be possible to issue a product announcing the transition from
a Flash Flood Warning to a longer duration Flood Warning.

O provides upgrade and downgrade capabilities. For example... it
would be possible to issue a product announcing the upgrade of
a Flood Watch to a Flood Warning.

O provides maximum ability to issue products combining different
types of watches... warnings and/or advisories for example...
it would be possible to issue a single product with multiple
segments for a point-based Flood Warning for one or more
river locations... a point-based flood advisory for one or
more locations... a point-based Flood Watch for one or more
locations ... and an areal Flood Warning for all or part of the
river basin affected by widespread small stream flooding.

O places emphasis on the versitle information contained within
valid time event code /vtec/ rather than product identifiers.

Possible future products showing benefits of unifying event-
based hydrologic products under the flw identifier can be found
on the hydrologic vtec web Page at /use lower case letters/:

http://www.NWS.NOAA.Gov/os/vtec/hydro_vtec.Shtml

The following are the event-based products that would be unified
under the Flood Warning /flw/ identifier:

Current product
identifier name

   ffa Flood Watch /areal/
   ffa Flash Flood Watch /areal/
   ffa Flood Watch for forecast points
   ffw Flash Flood Warning
   ffs flash flood statement
   flw Flood Warning for forecast points
   fls flood statement - follow-up to Flood Warning for
            forecast points
   flw areal Flood Warning
   fls flood statement - follow-up to areal Flood Warning
   fls flood statement - areal advisories
   fls flood statement - flood advisory for forecast points

Even though it would be possible to include multiple segments in
a flw product... warnings of high urgency such as flash floods
would continue to be issued as stand-alone products to ensure
they are not lost among other segments.

The change... if implemented... would mainly affect users who
automatically process and distribute NWS products to their
customers... such as radio and TV stations. The change would be
coordinated well in advance with these distributors and would
occur on a well publicized date. Therefore it would not affect
how the general public receives products from the internet...
NOAA Weather Radio all hazards... or media such as television or
radio. All current watches... warnings and advisories would
continue to be issued and each type of issuance would be clearly
identified within each flw product.

If event-based hydrologic products are unified under the flw
identifier... automated processing of flw products would require
parsing of vtec action... phenomenon and significance codes
contained in each segment. This parsing of vtec would reveal the
current status of each watch... warning and/or advisory contained
in the product and whether it is a new issuance... continuation
... Extension... cancellation... etc.

A one-Page summary of vtec is available at /use lower case letters/:

http://www.Weather.Gov/os/vtec/pdfs/vtec_explanation6.Pdf

Comments and suggestions on other ways the NWS can improve flood
products and the communication of flood risk also are welcome.
If a decision is made to proceed with the proposal... additional
public information statements will be issued over the next few
years to provide updates on plans for future implementation. The
NWS also will establish an ongoing dialog with partners and
other users on any changes through the next several years.

If you have comments or questions... please contact:

tim helble
National Weather Service
1325 east-west Highway
ssmc2 13434
Silver Spring MD 20910
Timothy.Helble@noaa.Gov

NWS public information statements are online at /use lower case letters/

http://www.Weather.Gov/os/notif.Htm