DECEMBER 2007 FLOOD EVENT

PART 2: FORECAST VERIFICATION

December 2007 Event Verification

The verification discussion is divided into two sections.In the first section the primary meteorological input, quantitative precipitation forecast (QPF), is evaluated.Evaluation of the hydrologic forecasts follows.

 

Meteorological Verification

This was the first major event where hydrometeorologists at the NWRFC utilized GFE to generate forecasted mean areal precipitation (FMAP) for input to hydrologic models.Hydrometeorolgical forecasters started using GFE generated QPF operationally this season.Each morning the HAS forecaster initializes NWRFC's QPF field using a mix of WFO ISC, HPC, and various model (GFS and NAM) QPF data.The forecaster uses GFE tools to derive a 10 day QPF product.PRISM climatological relationships are utilized to account for the influence of elevation.From the GFE grids QPF amounts are generated for the network of precipitation sites that was used in the NWSRFS model calibration.The FMAP is computed from these points using the calibration MAP weights.

 

Presentation of QPF verification will start off with spatial products generated during the event.This will be followed by basin specific analysis of point forecasts.Figure 1 displays the 24 hour QPF field in GFE for day 1. The derived calibration point precipitation values for that same 24 hour period are shown in figure 2.These can be compared with the image of observed precipitation displayed on the verification web page (see figure 3).


Figure 1 NWRFC GFE display ofday 1 QPF from 12/02/2007 12Z to 12/03/2007 12Z.

Figure 2 NWRFC point QPF plot for day 1 plot from 12/02/2007 12Z to 12/03/2007 12Z

Figure 3 Observed cumulative precipitation from 12/02/2007 12Z to 12/03/2007 12Z.


In fig. 1 there is a 7.45 inch 24 hour day-1 forecast accumulation sample value in the north Oregon Coast Range, along with 7.09 inch accumulation centered over the Washington Olympic Mountains. At the same fig. 1 sample points, the day-2 forecast 24 hour accumulations in fig. 4 are respectively 6.83 and 6.61 inches.The cumulative 2 day precipitation for this two areas are 14.28 and 13.7 inches respectively, which was in the range of observed values.

 

The day 2 GFE QPF grid shown in figure 4 showed that less precipitation was forecasted for Monday. The point QPF product displayed in figure 5 shows that the day 1 GFE QPF grid generated Monday morning (not shown) was an improvement over the forecast two days out.

 

Figure 4 NWRFC GFE display of  day 2 QPF from 12/03/2007 12Z to 12/04/2007 12Z.

 

Figure 5NWRFC point QPF plot for day 1 plot from 12/03/2007 12Z to 12/04/2007 12Z.

Figure 6Observed cumulative precipitation from 12/03/2007 12Z to 12/04/2007 12Z.


Wilson Basin

 

Figures 7 and 8 Comparison of Precipitation Forecasts for the Wilson River Basin.

Figures 9 and 10Scatter Diagrams of Observed Precipitationand NWRFC QPF for the Wilson River Basin.

 

 

Dec 1-3 2007 Event Verification Summary - Wilson Basin Sites

Event Performance Statistics

Event Performance - MAJOR EVENTS

 

 

Event Performance - MAJOR EVENTS

1.00"+ in 6-hour Time Period

 

 

4.00"+ in 24-hour Time Period

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

POD

0.47

0.77

0.30

 

 

POD

0.50

0.83

0.00

FAR

0.18

0.08

0.10

 

 

FAR

0.40

0.00

1.00

CSI

0.42

0.72

0.29

 

 

CSI

0.38

0.83

0.00

 

 

 

 

 

 

 

 

 

 

Event Performance - MODERATE EVENTS

 

 

Event Performance - MODERATE EVENTS

0.50"+ in 6-hour Time Period

 

 

2.00"+ in 24-hour Time Period

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

POD

0.90

0.93

0.71

 

 

POD

1.00

0.92

0.75

FAR

0.12

0.11

0.03

 

 

FAR

0.00

0.00

0.00

CSI

0.81

0.83

0.70

 

 

CSI

1.00

0.92

0.75

 

 

 

 

 

 

 

 

 

 

Event Performance - MINOR EVENTS

 

 

Event Performance - MINOR EVENTS

0.25"+ in 6-hour Time Period

 

 

1.00"+ in 24-hour Time Period

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

POD

0.89

0.93

0.88

 

 

POD

0.89

0.89

0.78

FAR

0.09

0.07

0.09

 

 

FAR

0.00

0.00

0.00

CSI

0.82

0.87

0.81

 

 

CSI

0.89

0.89

0.78

Table 1 Event QPF Verification Statistics for the Wilson River Basin.

 

Dec 1-3 2007 Event Verification Summary - Wilson Basin Sites

Daily Forecast Performance Statistics

Forecast Bias (Mean Algebraic Error)

 

 

Forecast Bias (Mean Algebraic Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

Day 1 Fcst

-0.078

-0.260

-0.236

 

 

Day 1 Fcst

-0.313

-1.038

-0.943

Day 2 Fcst

-0.324

-0.188

-0.476

 

 

Day 2 Fcst

-1.295

-0.750

-1.903

Day 3 Fcst

-0.508

-0.308

-0.610

 

 

Day 3 Fcst

-2.030

-1.232

-2.440

 

 

 

 

 

 

 

 

 

 

All Periods

-0.303

-0.252

-0.441

 

 

All Periods

-1.213

-1.007

-1.762

 

 

 

 

 

 

 

 

 

 

Forecast RMS Error

 

 

Forecast RMS Error

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

Day 1 Fcst

0.682

0.646

0.765

 

 

Day 1 Fcst

1.903

1.455

2.397

Day 2 Fcst

0.858

0.582

0.967

 

 

Day 2 Fcst

1.984

1.229

2.409

Day 3 Fcst

0.979

2.604

1.091

 

 

Day 3 Fcst

2.835

1.745

3.145

 

 

 

 

 

 

 

 

 

 

All Periods

0.848

1.585

0.950

 

 

All Periods

2.280

1.491

2.673

 

 

 

 

 

 

 

 

 

 

Forecast Error (Mean Absolute Error)

 

 

Forecast Error (Mean Absolute Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

Day 1 Fcst

0.405

0.310

0.452

 

 

Day 1 Fcst

1.367

1.075

1.633

Day 2 Fcst

0.592

0.352

0.581

 

 

Day 2 Fcst

1.295

0.790

1.903

Day 3 Fcst

0.617

0.478

0.695

 

 

Day 3 Fcst

2.030

1.232

2.440

 

 

 

 

 

 

 

 

 

 

All Periods

0.538

0.380

0.576

 

 

All Periods

1.564

1.032

1.992

Table 2 Daily QPF Verification Statistics for the Wilson River Basin.


Figures 11 and 12Comparison of Precipitation Forecasts for Jewell, Oregon (JELO3).

 

 

Figures 13 and 14Comparison of Precipitation Forecasts for Lees Camp, Oregon (LEEO3).

 

 

Nehalem Basin

 

Figures 15 and 16Comparison of Precipitation Forecasts for the Nehalem River Basin.

 

Figures 17 and 18 Scatter Diagrams of Observed Precipitation and NWRFC QPF for the Nehalem Basin.


Dec 1-3 2007 Event Verification Summary - Nehalem Basin Sites

Event Performance Statistics

Event Performance - MAJOR EVENTS

 

 

Event Performance - MAJOR EVENTS

1.00"+ in 6-hour Time Period

 

 

4.00"+ in 24-hour Time Period

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

POD

0.38

0.57

0.26

 

 

POD

0.33

0.42

0.00

FAR

0.16

0.08

0.08

 

 

FAR

0.33

0.00

1.00

CSI

0.36

0.55

0.26

 

 

CSI

0.29

0.42

0.00

 

 

 

 

 

 

 

 

 

 

Event Performance - MODERATE EVENTS

 

 

Event Performance - MODERATE EVENTS

0.50"+ in 6-hour Time Period

 

 

2.00"+ in 24-hour Time Period

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

POD

0.92

0.93

0.68

 

 

POD

0.94

0.89

0.67

FAR

0.10

0.08

0.02

 

 

FAR

0.00

0.00

0.00

CSI

0.83

0.86

0.67

 

 

CSI

0.94

0.89

0.67

 

 

 

 

 

 

 

 

 

 

Event Performance - MINOR EVENTS

 

 

Event Performance - MINOR EVENTS

0.25"+ in 6-hour Time Period

 

 

1.00"+ in 24-hour Time Period

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

POD

0.90

0.92

0.89

 

 

POD

0.92

0.92

0.83

FAR

0.08

0.07

0.07

 

 

FAR

0.00

0.00

0.00

CSI

0.84

0.86

0.83

 

 

CSI

0.92

0.92

0.83

Table 3 Event QPF Verification Statistics for the Nehalem River Basin.

 

Dec 1-3 2007 Event Verification Summary - Nehalem Basin Sites

Daily Forecast Performance Statistics

Forecast Bias (Mean Algebraic Error)

 

 

Forecast Bias (Mean Algebraic Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

Day 1 Fcst

-0.112

-0.289

-0.242

 

 

Day 1 Fcst

-0.448

-1.157

-0.968

Day 2 Fcst

-0.321

-0.236

-0.454

 

 

Day 2 Fcst

-1.283

-0.944

-1.816

Day 3 Fcst

-0.475

-0.327

-0.569

 

 

Day 3 Fcst

-1.900

-1.308

-2.278

 

 

 

 

 

 

 

 

 

 

All Periods

-0.303

-0.284

-0.422

 

 

All Periods

-1.210

-1.136

-1.687

 

 

 

 

 

 

 

 

 

 

Forecast RMS Error

 

 

Forecast RMS Error

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

Day 1 Fcst

0.610

0.600

0.687

 

 

Day 1 Fcst

1.724

1.563

2.174

Day 2 Fcst

0.779

0.588

0.860

 

 

Day 2 Fcst

1.846

1.381

2.267

Day 3 Fcst

0.907

0.686

1.016

 

 

Day 3 Fcst

2.587

1.716

2.902

 

 

 

 

 

 

 

 

 

 

All Periods

0.775

0.626

0.865

 

 

All Periods

2.088

1.559

2.469

 

 

 

 

 

 

 

 

 

 

Forecast Error (Mean Absolute Error)

 

 

Forecast Error (Mean Absolute Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

PQR

 

 

 

NWRFC

HPC

PQR

Day 1 Fcst

0.354

0.326

0.404

 

 

Day 1 Fcst

1.177

1.181

1.457

Day 2 Fcst

0.524

0.365

0.537

 

 

Day 2 Fcst

1.283

0.971

1.816

Day 3 Fcst

0.566

0.454

0.645

 

 

Day 3 Fcst

1.900

1.308

2.278

 

 

 

 

 

 

 

 

 

 

All Periods

0.481

0.382

0.529

 

 

All Periods

1.453

1.153

1.850

Table 4 Daily QPF Verification Statistics for the Nehalem River Basin.

 

Figures 19 and 20 Comparison of Precipitation Forecasts for Lees Camp, Oregon (LEEO3).

 

Figures 21 and 22 Comparison of Precipitation Forecasts for Vernonia, Oregon (VRNO3).

 

 

Chehalis Basin

 

Figures 23 and 24Comparison of Precipitation Forecasts for the Chehalis River Basin.

Figures 24 and 25 Scatter Diagrams of Observed Precipitation and NWRFC QPF for the Chehalis Basin.

 

Dec 1-3 2007 Event Verification Summary - Chehalis Basin Sites

Event Performance Statistics

Event Performance - MAJOR EVENTS

 

 

Event Performance - MAJOR EVENTS

1.00"+ in 6-hour Time Period

 

 

4.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.38

0.39

0.56

 

 

POD

0.46

0.38

0.56

FAR

0.34

0.18

0.32

 

 

FAR

0.27

0.00

0.29

CSI

0.32

0.36

0.44

 

 

CSI

0.39

0.38

0.45

 

 

 

 

 

 

 

 

 

 

Event Performance - MODERATE EVENTS

 

 

Event Performance - MODERATE EVENTS

0.50"+ in 6-hour Time Period

 

 

2.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.72

0.89

0.93

 

 

POD

0.59

0.86

1.00

FAR

0.25

0.25

0.22

 

 

FAR

0.14

0.11

0.33

CSI

0.58

0.69

0.74

 

 

CSI

0.54

0.77

0.67

 

 

 

 

 

 

 

 

 

 

Event Performance - MINOR EVENTS

 

 

Event Performance - MINOR EVENTS

0.25"+ in 6-hour Time Period

 

 

1.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.83

0.86

0.95

 

 

POD

0.97

0.96

1.00

FAR

0.15

0.14

0.15

 

 

FAR

0.01

0.03

0.05

CSI

0.72

0.75

0.81

 

 

CSI

0.96

0.94

0.95

Table 5 Event QPF Verification Statistics for the Chehalis River Basin.

 

 

Dec 1-3 2007 Event Verification Summary - Chehalis Basin Sites

Daily Forecast Performance Statistics

Forecast Bias (Mean Algebraic Error)

 

 

Forecast Bias (Mean Algebraic Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

-0.042

-0.120

0.126

 

 

Day 1 Fcst

-0.169

-0.479

0.502

Day 2 Fcst

-0.119

-0.102

-0.084

 

 

Day 2 Fcst

-0.477

-0.410

-0.336

Day 3 Fcst

-0.189

-0.098

-0.062

 

 

Day 3 Fcst

-0.754

-0.393

-0.248

 

 

 

 

 

 

 

 

 

 

All Periods

-0.117

-0.107

-0.007

 

 

All Periods

-0.467

-0.427

-0.027

 

 

 

 

 

 

 

 

 

 

Forecast RMS Error

 

 

Forecast RMS Error

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.517

0.436

0.654

 

 

Day 1 Fcst

1.249

1.183

2.095

Day 2 Fcst

0.481

0.432

0.573

 

 

Day 2 Fcst

1.282

1.183

1.827

Day 3 Fcst

0.549

0.431

0.589

 

 

Day 3 Fcst

1.572

1.123

1.834

 

 

 

 

 

 

 

 

 

 

All Periods

0.517

0.433

0.606

 

 

All Periods

1.375

1.163

1.923

 

 

 

 

 

 

 

 

 

 

Forecast Error (Mean Absolute Error)

 

 

Forecast Error (Mean Absolute Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.321

0.269

0.422

 

 

Day 1 Fcst

0.873

0.781

1.427

Day 2 Fcst

0.298

0.275

0.342

 

 

Day 2 Fcst

0.827

0.719

1.160

Day 3 Fcst

0.335

0.276

0.356

 

 

Day 3 Fcst

1.007

0.712

1.237

 

 

 

 

 

 

 

 

 

 

All Periods

0.318

0.273

0.373

 

 

All Periods

0.902

0.737

1.274

Table 6 Daily QPF Verification Statistics for the Chehalis River Basin.

 

Figures 26 and 27Comparison of Precipitation Forecasts for Frances, Washington (FRAW1).

 

Figures 27 and 28Comparison of Precipitation Forecasts for Grays Harbor, Washington (CGSW1).

 

 

Skokomish Basin

 

Figures 29 and 30  Comparison of Precipitation Forecasts for the Skokomish River Basin.

 

Figures 31 and 32 Scatter Diagrams of Observed Precipitation and NWRFC QPF for the Skokomish Basin.

Dec 1-3 2007 Event Verification Summary - Skokomish Basin Sites

Event Performance Statistics

Event Performance - MAJOR EVENTS

 

 

Event Performance - MAJOR EVENTS

1.00"+ in 6-hour Time Period

 

 

4.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.57

0.65

1.00

 

 

POD

0.41

0.33

1.00

FAR

0.39

0.22

0.67

 

 

FAR

0.21

0.00

0.25

CSI

0.41

0.55

0.33

 

 

CSI

0.37

0.33

0.75

 

 

 

 

 

 

 

 

 

 

Event Performance - MODERATE EVENTS

 

 

Event Performance - MODERATE EVENTS

0.50"+ in 6-hour Time Period

 

 

2.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.80

0.84

1.00

 

 

POD

0.97

1.00

1.00

FAR

0.14

0.15

0.37

 

 

FAR

0.09

0.08

0.50

CSI

0.71

0.73

0.63

 

 

CSI

0.89

0.92

0.50

 

 

 

 

 

 

 

 

 

 

Event Performance - MINOR EVENTS

 

 

Event Performance - MINOR EVENTS

0.25"+ in 6-hour Time Period

 

 

1.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.90

0.86

0.89

 

 

POD

0.97

0.92

1.00

FAR

0.10

0.03

0.08

 

 

FAR

0.03

0.00

0.00

CSI

0.82

0.84

0.83

 

 

CSI

0.95

0.92

1.00

Table 7 Event QPF Verification Statistics for the Skokomish River Basin.

 

 

 

Dec 1-3 2007 Event Verification Summary - Skokomish Basin Sites

Daily Forecast Performance Statistics

Forecast Bias (Mean Algebraic Error)

 

 

Forecast Bias (Mean Algebraic Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

-0.178

-0.325

0.416

 

 

Day 1 Fcst

-0.713

-1.300

1.663

Day 2 Fcst

-0.293

-0.286

0.178

 

 

Day 2 Fcst

-1.170

-1.143

0.713

Day 3 Fcst

-0.257

-0.257

0.252

 

 

Day 3 Fcst

-1.028

-1.027

1.007

 

 

 

 

 

 

 

 

 

 

All Periods

-0.243

-0.289

0.282

 

 

All Periods

-0.970

-1.157

1.128

 

 

 

 

 

 

 

 

 

 

Forecast RMS Error

 

 

Forecast RMS Error

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.893

0.876

0.785

 

 

Day 1 Fcst

1.742

2.238

2.336

Day 2 Fcst

0.914

0.808

0.315

 

 

Day 2 Fcst

2.282

2.023

1.058

Day 3 Fcst

0.883

0.784

0.391

 

 

Day 3 Fcst

2.185

1.875

1.235

 

 

 

 

 

 

 

 

 

 

All Periods

0.897

0.824

0.538

 

 

All Periods

2.083

2.051

1.643

 

 

 

 

 

 

 

 

 

 

Forecast Error (Mean Absolute Error)

 

 

Forecast Error (Mean Absolute Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.524

0.472

0.509

 

 

Day 1 Fcst

1.273

1.640

1.663

Day 2 Fcst

0.465

0.436

0.212

 

 

Day 2 Fcst

1.502

1.446

0.713

Day 3 Fcst

0.532

0.417

0.275

 

 

Day 3 Fcst

1.444

1.374

1.007

 

 

 

 

 

 

 

 

 

 

All Periods

0.507

0.441

0.332

 

 

All Periods

1.407

1.486

1.128

Table 8 Daily QPF Verification Statistics for the Skokomish River Basin.

 

Figures 33 and 34Comparison of Precipitation Forecasts for Cushman Dam, Washington (CSHW1).

 

 

Figures 35 and 36Comparison of Precipitation Forecasts for Aberdeen, Washington (ABEW1).

 

Elwha Basin

 

Figures 37 and 38Comparison of Precipitation Forecasts for the Elwha River Basin.

 

 

Figures 39 and 40 Scatter Diagrams of Observed Precipitation and NWRFC QPF for the Elwha River Basin.

 

Dec 1-3 2007 Event Verification Summary - Elwa Basin Sites

Event Performance Statistics

Event Performance - MAJOR EVENTS

 

 

Event Performance - MAJOR EVENTS

1.00"+ in 6-hour Time Period

 

 

4.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.42

0.21

 

 

 

POD

 

 

 

FAR

0.17

0.00

 

 

 

FAR

1.00

 

 

CSI

0.38

0.21

 

 

 

CSI

0.00

 

 

 

 

 

 

 

 

 

 

 

 

Event Performance - MODERATE EVENTS

 

 

Event Performance - MODERATE EVENTS

0.50"+ in 6-hour Time Period

 

 

2.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.74

0.69

 

 

 

POD

0.60

0.60

 

FAR

0.18

0.17

 

 

 

FAR

0.25

0.00

 

CSI

0.63

0.60

 

 

 

CSI

0.50

0.60

 

 

 

 

 

 

 

 

 

 

 

Event Performance - MINOR EVENTS

 

 

Event Performance - MINOR EVENTS

0.25"+ in 6-hour Time Period

 

 

1.00"+ in 24-hour Time Period

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

POD

0.80

0.82

 

 

 

POD

1.00

1.00

 

FAR

0.10

0.07

 

 

 

FAR

0.00

0.00

 

CSI

0.74

0.77

 

 

 

CSI

1.00

1.00

 

Table 9 Event QPF Verification Statistics for the Elwha River Basin.

 

 

Dec 1-3 2007 Event Verification Summary - Elwa Basin Sites

Daily Forecast Performance Statistics

Forecast Bias (Mean Algebraic Error)

 

 

Forecast Bias (Mean Algebraic Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.004

-0.224

 

 

 

Day 1 Fcst

0.014

-0.897

 

Day 2 Fcst

-0.111

-0.125

 

 

 

Day 2 Fcst

-0.444

-0.500

 

Day 3 Fcst

-0.132

-0.097

 

 

 

Day 3 Fcst

-0.529

-0.388

 

 

 

 

 

 

 

 

 

 

 

All Periods

-0.080

-0.149

 

 

 

All Periods

-0.320

-0.595

 

 

 

 

 

 

 

 

 

 

 

Forecast RMS Error

 

 

Forecast RMS Error

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.417

0.382

 

 

 

Day 1 Fcst

0.688

1.121

 

Day 2 Fcst

0.326

0.269

 

 

 

Day 2 Fcst

0.837

0.677

 

Day 3 Fcst

0.363

0.235

 

 

 

Day 3 Fcst

0.969

0.601

 

 

 

 

 

 

 

 

 

 

 

All Periods

0.370

0.302

 

 

 

All Periods

0.839

0.832

 

 

 

 

 

 

 

 

 

 

 

Forecast Error (Mean Absolute Error)

 

 

Forecast Error (Mean Absolute Error)

6-hour Time Period, All Stations

 

 

24-hour Time Period, All Stations

 

NWRFC

HPC

SEW

 

 

 

NWRFC

HPC

SEW

Day 1 Fcst

0.291

0.250

 

 

 

Day 1 Fcst

0.559

0.897

 

Day 2 Fcst

0.203

0.206

 

 

 

Day 2 Fcst

0.673

0.500

 

Day 3 Fcst

0.253

0.169

 

 

 

Day 3 Fcst

0.798

0.419

 

 

 

 

 

 

 

 

 

 

 

All Periods

0.249

0.208

 

 

 

All Periods

0.677

0.605

 

Table 10 Daily QPF Verification Statistics for the Elwha River Basin.


Figures 40 and 41Comparison of Precipitation Forecasts for Quilcene, Washington (QILW1).

 

Figures 42 and 43Comparison of Precipitation Forecasts for Elwha RS, Washington (ELHW1).

 

 

Flood Forecast Verification

 

Heavy precipitation on December 2 and 3, 2007 caused extensive flooding from the central Oregon Coast up to the Olympic Peninsula of Washington.The storm pushed 34 rivers above flood stage, 6 above major flood stage and 5 forecast locations set new record stages (see tables 1 and 2).For most of these rivers this was the most severe flooding since February of 1996, though the areal extent of this storm was less.A detailed analysis of the river forecasts was performed for the areas that were hardest hit.These areas were the Wilson, Nehalem, Chehalis, Skokomish and Elwha basins.

 

 

 

 

 

Peak

Forecast Point

NWSID

Stage

Time of Peak

Existing Record

Date

 

 

(ft)

 

(ft)

 

Mary's River near Philomath

PHIO3

21.02

12/4 05:00Z

21.07

12/30/2005

Luckiamute River near Suver

SUVO3

29.02

12/4 17:00Z

34.52

12/22/1964

South Yamhill at McMinnville