Display of Regional Spectral Model Results on an Internet Web Site

Doyle Pittman

Kenneth Wastrack

Tennessee Valley Authority

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The Tennessee Valley Authority (TVA) usesshort-range forecasts of temperature and

precipitation in the Tennessee Valley to helpmake daily decisions concerning power load

management, power marketing, and riversystem management.

Improvements in forecast accuracy can improvedecision-making and could save millions of

dollars each year.

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TVA has-modified the National WeatherService (NWS) Regional Spectral Model(RSM) to achieve forecast improvements.

The RSM is a limited-area (that is, regional)version of the Global Spectral Model (GSM)

developed at the National Centers forEnvironmental Predictions (NCEP).

Output from the GSM defines initial and updated boundary and interior

conditions for the RSM.

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The RSM divides the atmosphere into28 vertical layers and has a horizontal spatial

resolution of about 20 km (compared to 45 kmfor other NWS models).

This is small enough to depict the complextopography of the eastern portion of the

Tennessee Valley. TVA currently uses the RSMfor a domain of about 82o to 90o west longitude

and about 32o to 40o north latitude

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TVA RSM Domain

- Forecast Cities

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TVA RSM Process

Download GSM Files|

Run RSM Software on UNIX computer|

Create Graphics Files|

Transfer Files to IntraNet web server|

Use standard web browser to access information

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Precipitation ForecastMajor Forecast Areas

M S

K E N T U C K Y

G E O R G I A

N C

S C

V A

SOUTHWEST(SW)

EAST(ET)

NORTHEAST(NE)

A L A B A M ATennessee RiverDrainage Basin

CENTRAL(CN)

I L

NORTHWEST(NW)

T E N N E S S E E

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|<----- DAY - 1 ------>|<----- DAY - 2 ----->|<- DAY-3 ->|

6am 12p 6pm 12a 6am 12p 6pm 12a 6am 12p / / / / / / / / / / TOTAL 12p 6pm 12a 6am 12p 6pm 12a 6am 12p 6pm ---|-----------------------|-----------------------|-----------|------- NE 0.00 0.00 0.00 0.00 0.01 0.06 0.47 0.39 0.14 0.04 1.11

ET 0.00 0.00 0.00 0.00 0.01 0.01 0.17 0.24 0.04 0.03 0.49

CN 0.00 0.00 0.00 0.01 0.07 0.23 0.40 0.44 0.03 0.01 1.18

SW 0.00 0.00 0.00 0.07 0.20 0.36 0.41 0.33 0.00 0.00 1.39

NW 0.00 0.00 0.01 0.05 0.61 0.43 0.21 0.01 0.01 0.00 1.33 ---|-----------------------|-----------------------|-----------|-------

Precipitation ForecastMajor Forecast Areas

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Precipitation ForecastsEastern Sub-Basins

SOUTHWEST(SW)

EAST(ET)

NORTHEAST(NE)

Tennessee RiverDrainage Basin

CENTRAL(CN)

NORTHWEST(NW)

K E N T U C K Y

G E O R G I A

N O R T HC A R O L I N A

S O U T HC A R O L I N A

V I R G I N I A

A L A B A M A

T E N N E S S E E

Nashville

Chattanooga

Bristol

Knoxville

Norris

Cherokee

Ocoee #1 &Apalachia

EastCentral

Douglas

West Central

Little Tenn.above

Chilhowee

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Precipitation ForecastsEastern Sub-Basins

|<------ DAY - 1 ------>|<------ DAY - 2 ------>|<- DAY-3 ->|

6am 12p 6pm 12a 6am 12p 6pm 12a 6am 12p / / / / / / / / / / TOTAL 12p 6pm 12a 6am 12p 6pm 12a 6am 12p 6pm ---|-----------------------|-----------------------|-----------|------- Nor 0.00 0.00 0.00 0.00 0.02 0.12 0.71 0.39 0.13 0.05 1.43

Che 0.00 0.00 0.00 0.00 0.00 0.02 0.34 0.39 0.14 0.03 0.94

Dou 0.00 0.00 0.00 0.00 0.00 0.00 0.21 0.19 0.03 0.02 0.45

Lit 0.00 0.00 0.00 0.00 0.01 0.00 0.11 0.23 0.06 0.04 0.44

Oco 0.00 0.00 0.00 0.00 0.01 0.03 0.20 0.27 0.03 0.02 0.56

Ecn 0.00 0.00 0.00 0.01 0.04 0.12 0.35 0.52 0.03 0.02 1.09

Wcn 0.00 0.00 0.00 0.02 0.09 0.45 0.56 0.07 0.03 0.02 1.24

SW 0.00 0.00 0.00 0.07 0.20 0.36 0.41 0.33 0.00 0.00 1.39

NW 0.00 0.00 0.01 0.05 0.61 0.43 0.21 0.01 0.01 0.00 1.33 ---|-----------------------|-----------------------|-----------|-------

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Temperature ForecastsValley Cities

BNA - Nashville, TN CHA - Chattanooga, TN MEM - Memphis, TN TRI - Tri-Cities, TN TYS - Knoxville, TN HSV - Huntsville, AL

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Temperature ForecastsValley Cities

DATE HR BNA CHA MEM TRI TYS HSV19990225 18 53.1 57.0 61.9 39.0 50.0 57.019990225 19 50.3 53.5 57.3 38.1 48.1 52.819990225 20 47.8 50.8 54.4 37.2 46.2 50.119990225 21 45.5 48.6 52.7 36.2 44.4 48.519990225 22 43.4 46.9 51.9 34.9 42.5 47.419990225 23 41.4 45.3 51.4 33.3 40.5 46.719990225 24 39.5 43.6 50.9 31.2 38.5 45.819990226 01 37.7 41.8 49.9 28.6 36.3 44.419990226 02 36.1 40.1 48.8 26.0 34.2 42.819990226 03 35.1 38.6 47.8 23.6 32.6 41.419990226 04 34.7 37.7 47.2 22.0 31.7 40.319990226 05 35.2 37.6 47.5 21.5 31.7 40.119990226 06 36.8 38.6 48.9 22.6 33.1 40.919990226 07 39.6 40.8 51.6 25.7 35.9 43.119990226 08 43.3 43.9 55.3 30.1 39.7 46.219990226 09 47.4 47.4 59.4 35.1 44.0 49.919990226 10 51.5 50.9 63.6 40.3 48.2 53.719990226 11 55.1 54.0 67.3 44.7 51.9 57.1 . . . . . . . . . . . . . . . . . . . . . . . .19990228 17 46.3 49.2 49.6 45.3 47.9 47.819990228 18 42.9 45.3 47.5 41.3 43.0 44.9

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Graphical Displays

The RSM software creates graphical depictionsfor 6-hour intervals in several formats.

• Postscript (RSM native graphics)

• JPEG (Web browser compatibility)

• Animated GIF (assembled from 12 forecast images)

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Precipitation Forecasts6-hour Accumulations

36 Hours 42 Hours

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Precipitation Forecasts6-hour Accumulations

48 Hours 54 Hours

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Other Forecasts(54 Hours)

Pressure Wind

Note the low pressure trough and wind-shift along a linefrom southern Indiana to northern Alabama.

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Temperature Forecasts

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While the RSM provides short-range forecasts of sufficientdetail for the TVA Region, data results on UNIX computerare not easily accessible.

Using an IntraNet web server allows information to bewidely distributed throughout TVA.

Using JPEG and animated GIF graphics formats allowsviewing with a standard web browser.

Complex information is presented in a form that is easy tounderstand and can be readily accessed from desktop computers.

Advantage of Web Display

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Plume Particulate Model Displays

TVA is also evaluating other uses of the RSM.

One example is a plume particle model thatuses meteorological data based on the resultsof the RSM

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Plume Particulate Model DisplaysHour 6 Hour 11

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Plume Particulate Model DisplaysHour 16 Hour 21