Public Information Statement
Issued by NWS

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NOUS42 KTAE 271607
PNSTAE

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1207 PM EDT TUE SEP 27 2016

To: Emergency management officials, news media, and other users.

Effective Tuesday, November 1, 2016 at 1 pm EDT (1700 UTC) the
National Weather Service in Tallahassee will change the vertical
datum used for river forecast and data points within the Suwannee
River Water Management District`s (SRWMD) area of responsibility.
This includes the following rivers in the NWS Tallahassee area of
responsibility:

Aucilla River
Econfina River
Steinhatchee River
Suwannee River
Withlacoochee River

Currently, river observations at the data and forecast points on
these rivers are reported in height above sea level in the National
Geodetic Vertical Datum of 1929 (NGVD29). The SRWMD recently
completed a survey for each of these locations in the North American
Vertical Datum of 1988(NAVD88). Use of this new datum is more
accurate than the NGVD29 datum and also allows easier reference to
established flood maps and base flood elevations, which are depicted
in the NAVD88 datum.

Flood stages will be converted at most forecast and observation
points to height above sea level in NAVD88 and then rounded to the
nearest whole number, or nearest half foot, when the station is
affected by tides.

Flood stages for the Suwannee River at Dowling Park, Suwannee River
at Luraville, Suwannee River at Ellaville, and Suwannee River at
Branford, will be further modified based on recently completed
inundation mapping modelling for these locations.

These updates are a direct result of survey work completed by the
SRWMD, coordination between emergency management officials across
North Florida, The Florida Division of Emergency Management and the
United States Geological Survey in Florida.

The following river forecast points are included in this service change:

Aucilla River near Lamont (LAMF1)
Econfina River near Perry (ECOF1)
Steinhatchee River near Cross City (STEF1)
Suwannee River near Ellaville (ELLF1)*
Suwannee River near Dowling Park (DOUF1)*
Suwannee River near Luraville (LURF1)*
Suwannee River near Branford (BFDF1)*
Suwannee River near Wilcox (WCXF1)
Suwannee River at Manatee Springs (MTSF1)
Suwannee River at Fowlers Bluff (FWBF1)
Withlacoochee River near Pinetta (PINF1)

*additional flood stage modifications based on inundation mapping

The following river observation points are included in this service
change:

Aucilla River at Sneads Smokehouse Lake (ASHF1)
Suwannee River near Rock Bluff (RCKF1)
Suwannee River at Gopher River (SUWF1)
Withlacoochee River near Madison (WTMF1)
Withlacoochee River near Lee (WTHF1)

Documentation on these changes can be found at the following website:

Aucilla River:
http://www.weather.gov/media/tae/hydro/Aucilla.pdf
Suwannee River:
http://www.weather.gov/media/tae/hydro/Suwannee.pdf
Withlacoocheee River:
http://www.weather.gov/media/tae/hydro/Withlacoochee.pdf
Steinhatchee and Econfina Rivers:
http://www.weather.gov/media/tae/hydro/TaylorCounty.pdf

The data for these forecast and observation points are provided
through our partners, the United States Geological Survey and the
Suwannee River Water Management District. Without these
observations, forecasts and warnings within the Suwannee River Basin
would not be possible. You can learn more about stream gauges in
Florida by visiting:

http://fl.water.usgs.gov
http://www.srwmd.state.fl.us

To get the latest information on these and other river points in the
Tallahassee area of responsibility, please visit our website at:

http://water.weather.gov/ahps2/index.php?wfo=tae

River forecast and warning services for these forecast points are
supported by the National Weather Service in Tallahassee. You can
learn more about this office by visiting our website at:

http://www.weather.gov/tae

For further information regarding this change, please contact:

Kelly Godsey                      Jane Hollingsworth
Senior Service Hydrologist        Meteorologist in Charge
NWS Tallahassee Florida           NWS Tallahassee Florida
Love Building                     Love Building
Florida State University          Florida State University
Tallahassee, Florida 32306        Tallahassee, Florida 32306
(850) 942-8833 ext 228            (850) 942-8833 ext 222
Kelly.godsey@noaa.gov             Jane.Hollingsworth@noaa.gov


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