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The Hydrometeorological Prediction Center




HPC Verification


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QPF's:    24-Hourly    6-Hourly    Days 4-5    5-Day Total
Medium Range:    Min Temps    Max Temps    Prob of Pcpn (PoP)    HPC Grids
Sea-level Pressure

Quantitative Precipitation Forecasts

How Threat Scores and Bias are Computed

24-Hourly QPF's
Monthly Record Threat Scores

Annual HPC Day-1 / Day-2 / Day-3 Threat Scores
and Observed Areal Coverage;
Annual HPC Day-1 / Day-2 / Day-3 Bias
.50 inch (1961-2007) 1.00 inch (1961-2007) 2.00 inches (1970-2007)
Threat Bias Threat Bias Threat Bias

Annual HPC vs. NWP Guidance Threat Scores
1993-2007
1.00 inch
Day 1 Threat Percent Improvement Over NWP

Monthly HPC vs. NWP Guidance Threat Scores and Bias
March 2007 to March 2008
.50 inch 1.00 inch 2.00 inches
Day 1 Threat Bias Threat Bias Threat Bias
Day 2 Threat Bias Threat Bias Threat Bias
Day 3 Threat Bias Threat Bias Threat Bias

Monthly HPC Threat Score and Bias Comparisons (.50", 1.00", 2.00")
March 2007 to March 2008
Day 1 Day 2 Day 3
Threat Bias Threat Bias Threat Bias

Monthly HPC Threat Score and Bias Comparisons (Day 1 / Day 2 / Day 3)
March 2007 to March 2008
.50 inch 1.00 inch 2.00 inches
Threat Bias Threat Bias Threat Bias

NAM and GFS QPF Verification by Region


6-Hourly QPF's
Monthly Record Threat Scores

Monthly HPC vs. NWP Guidance Threat Scores
Update
March 2007 to March 2008
00-06 Hours .25 inch .50 inch

Monthly HPC vs. NWP Guidance Threat Scores
Day 1
March 2007 to March 2008
06-12 Hours .25 inch .50 inch
12-18 Hours .25 inch .50 inch
18-24 Hours .25 inch .50 inch
24-30 Hours .25 inch .50 inch

Monthly HPC vs. NWP Guidance Threat Scores
Day 2
March 2007 to March 2008
30-36 Hours .25 inch .50 inch
36-42 Hours .25 inch .50 inch
42-48 Hours .25 inch .50 inch
48-54 Hours .25 inch .50 inch

Monthly HPC vs. NWP Guidance Threat Scores
Day 3
March 2007 to March 2008
54-60 Hours .25 inch .50 inch
60-66 Hours .25 inch .50 inch
66-72 Hours .25 inch .50 inch
72-78 Hours .25 inch .50 inch

HPC vs. NWP Guidance - Threat Scores
April 2007 to March 2008
All 6-Hour Periods .25 inch .50 inch


Days 4-5 QPF's
Monthly HPC vs. NWP Guidance Threat Scores and Bias
March 2007 to March 2008
.50 inch 1.00 inch 2.00 inches
Threat Bias Threat Bias Threat Bias

Monthly HPC Threat Score and Bias Comparisons
.50", 1.00", 2.00"
March 2007 to March 2008
Threat Bias


5-Day Total QPF's
Monthly HPC vs. NWP Guidance Threat Scores and Bias
March 2007 to March 2008
.50 inch 1.00 inch 2.00 inches 3.00 inches 4.00 inches
Threat Bias Threat Bias Threat Bias Threat Bias Threat Bias

Monthly HPC Threat Score and Bias Comparisons
.50", 1.00", 2.00", 3.00", 4.00"
March 2007 to March 2008
Threat Bias


Medium-Range Forecasts

Overview of data plotted on annual charts

Minimum Temperatures

Annual Mean Absolute Error (MAE) Charts (1972 - 2007)
HPC MAE for days 3-7 min temp fcsts
HPC -vs- Guidance MAE for day 3 min temp fcsts
HPC -vs- Guidance MAE for day 4 min temp fcsts
HPC -vs- Guidance MAE for day 5 min temp fcsts


Monthly Performance Charts (Apr 2007 - Apr 2008)
HPC RMS errors for Days 3-7 min temp fcsts
HPC percent improvement over MOS MAE (adjusted stations only) for Days 3-7 min temp fcsts
HPC winning percent vs MOS for Days 3-7 min temp fcsts


Year-to-Date Performance Chart (January-April 2008)
HPC improvement over MOS MAE, including percentage of stations adjusted, for Days 3-7 min temp fcsts


Maximum Temperatures

Annual Mean Absolute Error (MAE) Charts (1972 - 2007)
HPC MAE for days 3-7 max temp fcsts
HPC -vs- Guidance MAE for day 3 max temp fcsts
HPC -vs- Guidance MAE for day 4 max temp fcsts
HPC -vs- Guidance MAE for day 5 max temp fcsts


Monthly Performance Charts (Apr 2007 - Apr 2008)
HPC RMS errors for Days 3-7 max temp fcsts
HPC percent improvement over MOS MAE (adjusted stations only) for Days 3-7 max temp fcsts
HPC winning percent vs MOS for Days 3-7 max temp fcsts


Year-to-Date Performance Chart (January-April 2008)
HPC improvement over MOS MAE, including percentage of stations adjusted, for Days 3-7 max temp fcsts


Probability of Precipitation (PoP)

Monthly Performance Charts - 24-Hour PoP (Apr 2007 - Apr 2007)
HPC Brier scores for days 3-7 PoP fcsts
HPC percent improvement over MOS Brier score (adjusted stations only) for days 3-7 PoP fcsts
HPC winning percent vs MOS for Days 3-7 PoP fcsts


Year-to-Date Performance Chart - 24-Hour PoP (January-April 2008)
HPC improvement over MOS MAE, including percentage of stations adjusted, for Days 3-7 PoP fcsts


Monthly Performance Charts - 12-Hour PoP (March 2007 - March 2008)
HPC Brier scores for days 3-7 12-Hour PoP forecasts
HPC percent improvement over MOS Brier score for days 3-7 12-Hour PoP forecasts

HPC Gridded Medium-Range Forecasts


How grids are verified
 
Monthly Performance Charts (March 2008)
Note:  MAE = Mean Absolute Error
 
Forecasts prepared by HPC meteorologists
MOS/HPC/NDFD Minimum Temperature 
(Days 4-7) 		MAE Bias
MOS/HPC/NDFD Maximum Temperature 
(Days 4-7) 		MAE Bias
MOS/HPC/NDFD 12-Hour PoP 
(Days 4-7) 		Brier Score

Products derived from forecasts prepared by HPC meteorologists
MOS/HPC/NDFD Dew Point Temperature 
(valid every 6 hours from F90-F180) 		MAE Bias
MOS/HPC/NDFD Wind Speed 
(valid every 6 hours from F90-F180) 		MAE Bias
MOS/HPC/NDFD Wind Direction 
(valid every 6 hours from F90-F180) 		MAE Bias
HPC/NDFD Cloud Cover 
(valid every 6 hours from F90-F180) 		MAE Bias

Mean Sea Level Pressure (PMSL)


HPC -vs- Guidance Anomaly Correlations

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Page last modified: Friday, 09-May-2008 18:35:14 GMT