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Weather Prediction Center
College Park, MD

WPC Verification



Jump To

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


Quantitative Precipitation Forecasts




How Threat Scores and Bias are Computed

24-Hourly QPF's


Monthly Record Threat Scores

Annual WPC Day-1 / Update / Day-2 Threat Scores
and Observed Areal Coverage;
Annual WPC Day-1 / Day-2 Bias
.50 inch (1972-2010) 1.00 inch (1965-2000) 2.00 inches (1970-2010)
Threat Bias Threat Bias Threat Bias

Annual WPC -vs- NWP Guidance Threat Scores
1993-2013
1.00 inch
Day 1 Threat

Monthly WPC -vs- NWP Guidance Threat Scores and Bias
July 2013 to July 2014
.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 WPC Threat Score and Bias Comparisons (.50", 1.00", 2.00")
July 2013 to July 2014
Day 1 Day 2 Day 3
Threat Bias Threat Bias Threat Bias

Monthly WPC Threat Score and Bias Comparisons (Day 1 / Day 2 / Day 3)
July 2013 to July 2014
.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 WPC -vs- NWP Guidance Threat Scores
Update
July 2013 to July 2014
00-06 Hours .25 inch .50 inch

Monthly WPC -vs- NWP Guidance Threat Scores
Day 1
July 2013 to July 2014
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 WPC -vs- NWP Guidance Threat Scores
Day 2
July 2013 to July 2014
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 WPC -vs- NWP Guidance Threat Scores
Day 3
July 2013 to July 2014
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



Days 4-5 QPF's


Monthly WPC -vs- NWP Guidance Threat Scores and Bias
June 2013 to June 2014
.50 inch 1.00 inch 2.00 inches
Threat Bias Threat Bias Threat Bias

Monthly WPC Threat Score and Bias Comparisons
.50", 1.00", 2.00"
June 2013 to June 2014
Threat Bias


5-Day Total QPF's


Monthly WPC -vs- NWP Guidance Threat Scores and Bias
June 2013 to June 2014
.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 WPC Threat Score and Bias Comparisons
.50", 1.00", 2.00", 3.00", 4.00"
June 2013 to June 2014
Threat Bias



Medium-Range Forecasts




Overview of data plotted on annual charts

Minimum Temperatures



Annual Mean Absolute Error (MAE) Charts (1972 - 2013)
WPC MAE for days 3-7 min temp fcsts
WPC -vs- Guidance MAE for day 3 min temp fcsts
WPC -vs- Guidance MAE for day 4 min temp fcsts
WPC -vs- Guidance MAE for day 5 min temp fcsts
WPC -vs- Guidance MAE for day 6 min temp fcsts
WPC -vs- Guidance MAE for day 7 min temp fcsts


Monthly Performance Charts (August 2013 - August 2014)
WPC RMS errors for Days 3-7 min temp fcsts
WPC percent improvement over MOS MAE (adjusted stations only) for days 3-7 min temp fcsts
WPC winning percent vs MOS for days 3-7 min temp fcsts



Maximum Temperatures



Annual Mean Absolute Error (MAE) Charts (1972 - 2013)
WPC MAE for days 3-7 max temp fcsts
WPC -vs- Guidance MAE for day 3 max temp fcsts
WPC -vs- Guidance MAE for day 4 max temp fcsts
WPC -vs- Guidance MAE for day 5 max temp fcsts
WPC -vs- Guidance MAE for day 6 max temp fcsts
WPC -vs- Guidance MAE for day 7 max temp fcsts


Monthly Performance Charts (August 2013 - August 2014)
WPC RMS errors for Days 3-7 max temp fcsts
WPC percent improvement over MOS MAE (adjusted stations only) for days 3-7 max temp fcsts
WPC winning percent vs MOS for days 3-7 max temp fcsts



Probability of Precipitation (PoP)



Monthly Performance Charts (August 2013 - August 2014)

WPC Brier scores for days 3-7 PoP fcsts
WPC percent improvement over MOS Brier score (adjusted stations only) for days 3-7 PoP fcsts
WPC winning percent vs MOS for Days 3-7 PoP fcsts


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

WPC Gridded Medium-Range Forecasts



How grids are verified

Monthly Performance Charts (July 2006)
WPC/NDFD/MOS Minimum Temperature RMS Errors (days 4-7)
WPC/NDFD/MOS Maximum Temperature RMS Errors (days 4-7)
WPC/NDFD/MOS 12-Hour PoP Brier Score (days 4-7)
WPC/NDFD Wind Direction RMS Errors
(valid every 6 hours from F90-F180)
WPC/NDFD Wind Speed RMS Errors
(valid every 6 hours from F90-F180)
WPC/NDFD Dew Point Temperature RMS Errors
(valid every 6 hours from F90-F180)
WPC/NDFD Cloud Cover RMS Errors
(valid every 6 hours from F90-F180)


Mean Sea Level Pressure (PMSL)

WPC -vs- Guidance Anomaly Correlations


Questions? Comments? Click here to send mail to the WPC.

Last Updated September 3, 2014