General Information

on the

Fire Weather System

Of

Georgia Forestry Commission

 

 

Weather Forecast

Georgia Forestry Commission's (GFC) used National Weather Service’s (NWS) Fire Weather Dashboard to get to weather products produced by the NWS.  

 

GFC produces observed or forecast weather maps/graphs.  GFC also generates current and forecast fire danger rating information for GFC and co-operators weather station network.  Other products available through GFC's Fire Weather Homepage (https://weather.gfc.state.ga.us) include Current weather at National Weather Service's (NWS) weather stations in Georgia, historical data from the GFC weather stations, and a climate outlook from NWS's Climate Prediction Center.

 

NFDRS

NFDRS stands for National Fire Danger Rating Systems.  The current version of the National Fire Danger Rating System was developed by the US Forest Service (Burgan, 1988) for predicting fire occurrence and behavior based on fuels, topography, man‑caused fire risk factors and current weather conditions. Although the National Fire Danger Rating System indices should not be directly applied to any particular site, they do supply the practitioner with a set of indices that can be used to compare recent history, and adjacent fire management areas.  Thus, it is very important to understand the principles of fire danger rating:

  1. Fire danger rating relates only to the potential of the initiating fire.
  2. The ratings are relative, not absolute.  Relationships are linear except in use of burning index.
  3. Fire danger is rated from a worst case approach
  4. Fire danger is rated for a broad fuel model.

Experienced practitioners can translate these general area based indices to probable fire behavior at specific burn site.  Detailed explanation of the fire danger indices can be found by clicking "Explanation of NFDRS Indices" on the fire weather homepage.

 

Weather data are input into NFDRS and a number of indices are produced.  These fire danger indices are used to support prescribed burning activities and wildfire control operations.  Weather data are collected automatically daily at 1:00pm EST.  Then, fire danger indices will be computed.  Weather stations can be called at any time when data are needed to support forestry operations.

 

Weather Station Network

GFC operates a network of 19 automated weather stations throughout the state (Figure 1).  The stations record current weather conditions each hour.  Weather data from stations maintained by cooperating agencies, including US Forest Service, US Park Service, Department of Defense and University of Georgia, are collected as well.

 

 


Figure 1 Location of GFC and Co-operators (excluding UGA) fire danger weather stations.

 

 

GFC currently uses NFDRS fuel models C, D, and E.  Definitions of the various fuel models are included in (Appendix A).   Location and fuel model associated with each station is shown in Table 1.  The Georgia Forestry Commission uses Burning Index (BI) to determine Class Day.  The determination points are station specific based on BI percentile distribution at the station.  The BI determination points for all the stations are listed in Table 2.  Table 3 shows the Energy Release Component (ERC) percentile points for all stations. 

 

Table 1.  Name, location, elevation, and NFDRS fuel model used for the weather stations accessed by the GFC (excluding UGA stations)

Station Name

County

Latitude

Longitude

Fuel Model

WIMS ID

NESDIS ID

Owner

Chatsworth

Murray

34.7664

-84.7589

E

90401

310007FC

GFC

Dawsonville

Dawson

34.3763

-84.0599

C

91101

3100148A

GFC

Dallas

Paulding

33.8334

-84.7400

E

92201

31002110

GFC

Watkinsville

Oconee

33.8887

-83.4191

C

92702

31003266

GFC

Newnan

Coweta

33.3654

-84.8597

C

92901

310044F6 

GFC

Washington

Wilkes

33.7807

-82.8161

C

93501

31005780 

GFC

Brender NF

Jones

33.0506

-83.7164

C

94301

3100621A   

GFC

Louisville

Jefferson

32.9860

-82.3823

C

94501

3100716C  

GFC

Milledgeville

Baldwin

33.0103

-83.2073

C

93601

310081E8       

GFC

Americus

Sumter

32.1106

-84.1841

C

95501

3100929E    

GFC

McRae

Wheeler

32.0942

-82.8820

C

96201

3100A704

GFC

Metter

Candler

32.3913

-82.0373

C

96301

3100B472

GFC

Midway

Liberty

31.7842

-81.4386

D

96801

3100C2E2  

GFC

Baxley

Appling

31.7136

-82.3877

D

97701

3100D194       

GFC

Adel

Cook

31.0336

-83.4951

D

98401

3100E40E

GFC

Sterling

Glynn

31.2570

-81.6107

D

98801

3100F778  

GFC

Camilla

Mitchell

31.2141

-84.2362

C

98201

31010506

GFC

Waycross

Ware

31.2466

-82.4014

D

99701

31011670

GFC

Byromville

Dooly

32.1681

-83.9747

C

95701

310123EA

GFC

Cochran

Pulaski

32.3984

-83.2797

C

95301

32B4948A

GFC

Oakland

Marion

33.3654

-84.5555

C

95101

32B49A58

GFC

Bainbridge

Decatur

30.9706

-84.6343

C

99101

32B4892E

GFC

Armuchee

Walker

34.6953

-85.1736

C

90201

32732154

USFS

Brasstown

Towns

34.8028

-83.7100

C

90701

327357C4

USFS

Camp Merrill

Lumpkin

34.6087

-84.1309

C

91201

327314CE

USFS

Chattooga

Habersham

34.6403

-83.5219

C

91301

32737128

USFS

Cohutta

Murray

34.9225

-84.6594

C

90402

32733222

USFS

Dyar Pasture

Greene

33.6473

-83.2946

C

93502

32D3B260

USFS

Eddy Tower

FL

30.5483

-82.3483

D

81302

32876570

FWS

Fort Benning

Chattahoochee

32.3967

-84.8700

C

 

FBE0062C

DoD

Fort Gordon

Richmond

33.4256

-82.0441

C

 

FE100312

DoD

Jones Island (Fargo)

Charlton?

30.8289

-82.3600

D

99802

8372A52E

FWS

Oconee

Jasper

33.2083

-83.7136

C

93701

3273625E

USFS

Oke-East (Folkston )

Ware

30.7403

-82.1278

D

99801

32931144

FWS

Oke-NW

Charlton

30.9752

-82.3964

D

99803

32B00A00

FWS

SavannahNWR

GA

32.1000

-81.0833

C

384201

8376F068

FWS

Stafford

Camden

30.9172

-81.4294

D

99902

FA65A70E

NPS

Tallulah

Rabun

34.9058

-83.3344

C

90802

327381AC

USFS

Toccoa

Union

34.7650

-84.0744

C

90601

327344B2

USFS

Moody AFB

Lowndes

30.9700

-83.1900

D

 

32B76DD2

DoD

Notes:

     The abbreviations are noted below.

           GFC    - Georgia Forestry Commission

           DoD    - Department of Defense

           FWS     - U.S. Fish and Wildlife Service 

           NPS      - U.S Department of Interior, Park Service

           USFS  - U.S. Department of Agriculture, Forest Service

 

      All Locations are North latitude and West(-) longitude.


 

Table 2: Class Day determination points

Station/

Fuel Model

Class 1

Class 2

Class 3-

Class 3

Class 3+

Class 4

Class5

Determination Points

Valid Time

Determination Points

Based on

Description

Low

Moderate

Moderate to High

High

High to Very High

Very High

Extreme

------

 

BI Percentiles

0th to 20th

21st to 45th

46th to 60th

61st to 80th

81st to 90th

90th to 97th

97th to 100th

------

 

Americus      

0

6

12

15

18

21

25

2018-

2007-2016

Bainbridge

0

7

12

14

17

20

23

2021-

Using Camilla points

Baxley         

0

43

65

75

88

98

113

2018-

2007-2016

Brender NF    

0

2

8

10

12

14

17

2018-

2007-2016

Brunswick     

0

31

51

60

72

79

89

2018-

2007-2016

Byromville    

0

6

12

14

18

21

24

2018-

2007-2016

Camilla       

0

7

12

14

17

20

23

2018-

2007-2016

Chatsworth    

0

16

25

28

34

38

43

2018-

2007-2016

Cochran

0

6

11

13

16

19

22

2021-

Using McRae points

Adel

0

41

62

72

85

94

106

2018-

2007-2016

Dallas        

0

8

17

19

23

26

29

2018-

2007-2016

Dawsonville   

0

0

9

11

14

17

19

2018-

2007-2016

Louisville    

0

3

11

14

17

19

22

2018-

2007-2016

McRae         

0

6

11

13

16

19

22

2018-

2007-2016

Metter        

0

5

11

12

16

18

21

2018-

2007-2016

Midway        

0

32

51

59

69

75

84

2018-

2007-2016

Milledgeville 

0

4

11

13

16

18

22

2018-

2007-2016

Newnan        

0

2

10

12

15

17

20

2018-

2007-2016

Oakland

0

6

12

15

18

21

25

2021-

Using Americus points

Washington    

0

4

11

13

17

19

22

2018-

2007-2016

Watkinsville  

0

4

11

14

17

19

23

2018-

2007-2016

Waycross      

0

45

67

77

90

99

114

2018-

2007-2016

Camp Merrill     

0

0

7

10

13

15

18

2018-

2007-2016

Eddy Tower       

0

37

56

65

76

83

99

2018-

2007-2016

Fargo            

0

35

58

68

80

88

100

2018-

2007-2016

Folkston         

0

39

61

71

86

95

111

2018-

2007-2016

Fort Benning     

0

2

10

13

16

18

22

2018-

2007-2016

Savannah         

0

0

5

10

14

16

20

2018-

2007-2016

Stafford         

0

28

45

51

67

79

93

2018-

2007-2016

Armuchee

0

1

15

17

20

23

26

2024-

2019-2023

Brasstown

0

0

4

9

13

16

19

2018-

2007-2016

Chattooga   

0

0

10

14

18

21

26

2018-

2007-2016

Cohutta     

0

1

11

14

17

19

23

2021-

2017-2020

DyarPasture 

0

0

6

9

13

15

18

2018-

2007-2016

Oconee      

0

3

11

12

15

18

21

2018-

2007-2016

Tallulah    

0

1

9

12

15

18

23

2018-

2007-2016

Toccoa      

0

0

7

10

13

15

19

2018-

2007-2016

Moody AFB

0

41

62

72

85

94

106

2018-

Using Adel points

Fort Gordon

0

3

11

14

17

19

22

2018-

Using Louisville points

Oke-NW

0

52

67

75

89

95

107

2018-

2016

Note: The listed values are the minimum value for each Class day.  For example, when Americus has BI of 22-24, it has Class 4 Day. 

 

Table 3: Energy Release Component (ERC) Percentiles

ERC Percentiles

0th to 20th

21st to 45th

46th to 60th

61st to 80th

81st to 90th

90th to 97th

97th to 100th

Determination Points

Valid Time

Determination Points

Based on

Americus      

0

5

11

14

19

22

26

2018-

2007-2016

Bainbridge

0

6

11

14

18

22

25

2021-

Using Camilla points

Baxley        

6

36

48

51

58

62

67

2018-

2007-2016

Brender NF    

0

3

10

12

17

20

25

2018-

2007-2016

Brunswick     

3

30

46

50

56

60

66

2018-

2007-2016

Byromville    

0

6

11

14

20

23

27

2018-

2007-2016

Camilla       

0

6

11

14

18

22

25

2018-

2007-2016

Chatsworth    

0

8

13

15

20

22

25

2018-

2007-2016

Cochran

0

6

11

14

19

22

26

2021-

Using McRae points

Adel

6

34

49

53

60

64

69

2018-

2007-2016

Dallas        

0

7

13

15

19

22

25

2018-

2007-2016

Dawsonville   

0

0

10

12

17

22

26

2018-

2007-2016

Louisville    

0

4

12

15

20

23

26

2018-

2007-2016

McRae         

0

6

11

14

19

22

26

2018-

2007-2016

Metter        

0

5

11

13

17

20

25

2018-

2007-2016

Midway        

5

30

46

51

56

60

66

2018-

2007-2016

Milledgeville 

0

4

11

13

17

20

26

2018-

2007-2016

Newnan        

0

2

10

12

17

20

24

2018-

2007-2016

Oakland

0

5

11

14

19

22

26

2021-

Using Americus points

Washington    

0

5

11

13

19

22

25

2018-

2007-2016

Watkinsville  

0

5

10

13

17

20

24

2018-

2007-2016

Waycross      

6

38

49

53

59

64

69

2018-

2007-2016

Camp Merrill     

0

1

8

10

15

18

22

2018-

2007-2016

Eddy Tower       

5

34

48

52

59

62

66

2018-

2007-2016

Fargo             

3

32

47

52

58

62

69

2018-

2007-2016

Folkston         

6

37

46

51

57

61

65

2018-

2007-2016

Fort Benning     

0

4

10

13

19

23

31

2018-

2007-2016

Savannah         

0

3

8

11

17

25

42

2018-

2007-2016

Stafford         

6

23

48

54

63

68

74

2018-

2007-2016

Armuchee

0

2

9

11

15

19

24

2018-

2007-2016

Brasstown

0

1

5

8

12

14

18

2018-

2007-2016

Chattooga   

0

2

9

12

17

21

28

2018-

2007-2016

Cohutta     

0

2

8

11

14

17

22

2018-

2007-2016

DyarPasture 

0

1

6

8

11

14

21

2018-

2007-2016

Oconee       

0

4

10

12

17

21

25

2018-

2007-2016

Tallulah    

0

1

8

11

15

18

28

2018-

2007-2016

Toccoa      

0

1

6

9

12

15

22

2018-

2007-2016

Moody AFB

6

34

49

53

60

64

69

2018-

Using Adel points

Fort Gordon

0

4

12

15

20

23

26

2018-

Using Louisville points

Oke-NW

6

48

54

57

61

63

67

2018-

2016

Note: The listed values are the minimum value for each Percentile range.  For example, when Americus has ERC of 22-25, it between 90th and 97th percentile. 

 

 

 

REFERENCES

Deeming, John E.; Burgan, Robert E.; Cohen, Jack D. The National Fire-Danger Rating System – 1978. 1988 Revisions to the 1978 National Fire-Danger Rating System.  General Technical Report INT-39.  Ogden, UT: US Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station; 1977. 63pp..

 

Paul, J.T., and  J. Clayton.  User manual: Forestry  Weather Interpretation System (FWIS).  Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station and Atlanta, GA:  Southeastern Area State and  Private Forestry, in cooperation with the U.S. National Weather Service, NOAA, Silver Spring, M;. 1978. 83pp.

 

 

APPENDIX A

FUEL MODEL DEFINITIONS

Definitions extracted from (Deeming, et al. 1977).

 

FUEL MODEL A

This fuel model represents western grasslands vegetated by annual grasses and forbs. Brush or trees may be present but are very sparse, occupying less than one third of the area. Examples of types where Fuel Model A should be used are cheatgrass and medusahead. Open pinyon-juniper, sagebrush-grass, and desert shrub associations may appropriately be assigned this fuel model if the woody plants meet the density criteria. The quantity and continuity of the ground fuels vary greatly with rainfall from year to year.

 

FUEL MODEL B

Mature, dense fields of brush 6 feet or more in height are represented by this fuel model. One-fourth or more of the aerial fuel in such stands is dead. Foliage burns readily. Model B fuels are potentially very dangerous, fostering intense, fast-spreading fires. This model is for California mixed chaparral generally 30 years or older. The F model is more appropriate for pure chamise stands. The B model may also be used for the New Jersey pine barrens.

 

FUEL MODEL C

Open pine stands typify Model C fuels. Perennial grasses and forbs are the primary ground fuel but there is enough needle litter and branchwood present to contribute significantly to the fuel loading. Some brush and shrubs may be present but they are of little consequence. Situations covered by Fuel Model C are open, longleaf, slash,ponderosa,Jeffrey, and sugar pine stands. Some pinyon-juniper stands may qualify.

 

FUEL MODEL D

This fuel model is specifically for the palmetto-gallberry understory-pine overstory association of the southeast coastal plains. It can also be used for the so-called "low pocosins" where Fuel Model 0 might be too severe. This model should only be used in the Southeast because of a high moisture of extinction.

 

FUEL MODEL E

Use this model after leaf fall for hardwood and mixed hardwood-conifer types where the hardwoods dominate. The fuel is primarily hardwood leaf litter. The oakhickory types are best represented by Fuel Model E, but E is an acceptable choice for northern hardwoods and mixed forests of the Southeast. In high winds, the fire danger may be underrated because rolling and blowing leaves are not accounted for. In the summer after the trees have leafed out, Fuel Model E should be replaced by Fuel Model R

 

FUEL MODEL F

Fuel Model F is the only one of the 1972 NFDRS Fuel Models whose application has changed. Model F now represents mature closed chamise stands and oakbrush fields of Arizona, Utah, and Colorado. It also applies to young, closed stands and mature, open stands of California mixed chaparral. Open stands of pinyon-juniper are represented; however, fire activity will be overrated at low windspeeds and where there is sparse ground fuels.

 

 

FUEL MODEL G

Fuel Model G is used for dense conifer stands where there is a heavy accumulation of litter and downed woody material. Such stands are typically overmature and may also be suffering insect, disease, wind, or ice damage-natural events that create a very heavy buildup of dead material on the forest floor. The duff and litter are deep and much of the woody material is more than 3 inches in diameter. The undergrowth is variable but shrubs are usually restricted to openings. Types meant to be represented by Fuel Model G are hemlock-Sitka spruce, Coast Douglas-fir, and windthrown or bug-killed stands of lodgepole pine and spruce.

 

FUEL MODEL H

The short-needled conifers (white pines, spruces, larches, and firs) are represented by Fuel Model H. In contrast to Model G fuels, Fuel Model H describes a healthy stand with sparse undergrowth and a thin layer of ground fuels. Fires in H fuels are typically slow spreading and are dangerous only in scattered areas where the downed goody material is concentrated.

 

FUEL MODEL I

Fuel Model I was designed for clearcut conifer slash where the total loading of materials less than 6 inches in diameter exceeds 25 tons/acre. After settling and the fines (needles and twigs) fall from the branches, Fuel Model I will overrate the fire Potential. For lighter loadings of clearcut conifer slash, use Fuel Model J, and for light thinnings and partial cuts where the slash is scattered under a residual overstory, use Fuel Model K.

 

FUEL MODEL J

This model complements Fuel Model I. It is for clearcuts and heavily thinned conifer stands where the total loading of materials less than 6 inches in diameter is less than 25 tons/acre. Again, as the slash ages, the fire potential will be overrated

 

FUEL MODEL K

Slash fuels from light- thinnings and partial cuts in conifer stands are represented by Fuel Model K. Typically the slash is scattered about under an open overstory. This model applies to hardwood slash and to southern pine clearcuts where the loading of all Fuels is less than 15 tons/acre.

 

FUEL MODEL L

This fuel model is meant to represent western grasslands vegetated by perennial grasses. The principal species are coarser and the loadings heavier than those in Model A fuels. Otherwise the situations are very similar; shrubs and trees occupy less than one-third of the area. The quantity of fuel in these areas is more stable from year to year. In sagebrush areas Fuel Model T may be more appropriate.

 

FUEL MODEL N

This fuel model was constructed specifically for the sawgrass prairies of south Florida. It may be useful in other marsh situations where the fuel is coarse and reedlike. This model assumes that one-third of the aerial portion of the plants is dead fast-spreading, intense fires can occur even over standing water.

 

FUEL MODEL O

The O fuel model applies to dense, brushlike fuels of the Southeast. O fuels, except for a deep litter layer, are almost entirely living in contrast to B fuels. The foliage burns readily except during the active growing season. The plants are typically over 6 feet tall and are often found under an open stand of pine. The high pocosins of the Virginia, North and South Carolina coasts are the ideal of Fuel Model O.  If the plants do not meet the 6-foot criteria in those areas, Fuel Model D should be used.

 

FUEL MODEL P

Closed, thrifty stands of long-needled southern pines are characteristic of P fuel: A 2- to 4-inch layer of lightly compacted needle litter is the primary fuel. Some small diameter branchwood is present but the density of the canopy precludes more than a scattering of shrubs and grass.  Fuel Model P has the high moisture of extinction characteristic of the Southeast. The corresponding model for other long-needled pines is U.

 

FUEL MODEL Q

Upland Alaskan black spruce is represented by Fuel Model Q. The stands are dense but have frequent openings filled with usually inflammable shrub species. The forest floor is a deep layer of moss and lichens, but there is some needle litter and small-diameter branchwood. The branches are persistent on the trees, and ground fires easily reach into the tree crowns. This fuel model may be useful for jack pine stands in the Lake States. Ground fires are typically slow spreading, but a dangerous crowning potential exists. Users should be alert to such events and note those levels of Spread Component (SC) and BI when crowning occurs.

 

FUEL MODEL R

This fuel model represents the hardwood areas after the canopies leaf out in the spring. It is provided as the off-season substitute for E. It should be used during the summer in all hardwood and mixed conifer-hardwood stands where more than half of the overstory is deciduous.

 

FUEL MODEL S

Alaskan or alpine tundra on relatively well-drained sites is the S fuel. Grass and low shrubs are often present, but the principal fuel is a deep layer of lichens and moss. Fires in these fuels are not fast spreading or intense, but are difficult to extinguish.

 

FUEL MODEL T

The bothersome sagebrush-grass types of the Great Basin and the Intermountain West are characteristic of T fuels. The shrubs burn easily and are not dense enough to shade out grass and other herbaceous plants. The shrubs must occupy at least one-third of the site or the A or L fuel models should be used. Fuel Model T might be used for immature scrub oak and desert shrub associations in the West, and the scrub oak-wire grass type in the Southeast.

 

FUEL MODEL U

Closed stands of western long-needled pines are covered by this model. The ground fuels are primarily litter and small branchwood. Grass and shrubs are precluded by the dense canopy but occur in the occasional natural opening. Fuel Model U should be used for ponderosa, Jeffrey, sugar pine, and red pine stands of the Lake States. Fuel Model P is the corresponding model for southern pine plantations.