# Presentation: 769966

## An Inside Look at CPC’s Medium and Long-Range Forecasts

- <date/time>

- An Inside Look at CPC’s Medium and Long-Range Forecasts

- Scott Handel
- NOAA-NWS-Climate Prediction Center
- Camp Springs, Maryland
- _[scott](mailto:Scott.handel@noaa.gov)__[.handel@noaa.gov](mailto:Scott.handel@noaa.gov)_
- 301-763-8000, ext 7597

## National Centers for Environmental Prediction (NCEP) “Seamless Suite”

- CPC

## Part I:  Medium-Range Forecasts

- What are the products?
-  How Do I Interpret Them?
- How Are They Produced?
- How Skillful are They?

## Forecast Maps and Bulletins

- Each day,between 3 and 4 PM Eastern Time, CPC issues a set of 6-10 day and week 2 outlooks.  These are formulated by a forecaster (Monday through Friday) and are automated on weekends.  There are two 500 mb height maps, four surface maps and a single bulletin.

- Sample 6-10 day outlook 500 mb height and anomaly forecast map from CPC web page.

## Generic 6-10/8-14 Day Forecast Map

- B

- N

- N

- A

- 33

- 33

- 40

- 40

- 50

- N=Near Normal Category
- Contours are labeled with the total probability for the indicated category.
- Temperature probabilities based on normal distribution
- Precipitation more complicated

_**Generic 6-10/8-14 Day Forecast Map**_

## Official 6-10 Day T Forecast

- _Minneapolis_
- Below: 42%
- Normal: 33%
- Above: 24%

- _Phoenix_
- Below: 21%
- Normal: 33%
- Above: 45%

- _Washington_
- Below: 30%
- Normal: 40%
- Above: 30%

## The “Dry Station” Problem

- Percentage of Pentads with No Precipitation
-                               (JULY)

- Arid

- Semi-Arid

- Normal

## Official 6-10 day P forecast

- _Reno(Arid)_
- Below: NA
- Normal: NA
- Above: NA

- _Phoenix(__Semi-Arid__)_
- Below: NA
- Normal: NA
- Above: NA

- _Washington_
- Below: 23%
- Normal: 33%
- Above: 44%

## Official 6-10 day 500-HPA forecast

## 6-10 day/week 2 process schematic

- Multi-model ensemble 9:00 AM

- Weighted average of model 500 hPa height

- Downscale: get surface weather from 500 mb height via analogs, regression, neural network.

- R

- R

- Forecaster formulates maps of predicted T, P, PMD bulletin

- Disseminate via web, AWIPS, FOS 3-4 PM

- R

- = Forecaster reconciliation of tools required

## 6-10 Day 500-HPA Forecast Models

- ECMWF ENS MEAN

-     CAN ENS MEAN

-     GFS ENS MEAN

-            00Z GFS

## 6-10 Day 500-HPA Anomaly Correlations(GFS ENS MEAN)

## 6-10 Day Temperature Tools

- Klein (GFS MEAN)

- Neural Net (GFS MEAN)

-      CDC Reforecast

- Analog (GFS MEAN)

## Daily Skill of Temperature Forecast Tools (0z GFS)

- _Daily Skill of Temperature Forecast Tools (0z GFS)_

- _Heidke Skill Score_
- s=((c-e)/(t-e))*100c = # hitse = # chance hitst = # forecasts

## The End Result: 6-10 Day Skill

- _Heidke Skill Score_
- s=((c-e)/(t-e))*100c = # hitse = # chance hitst = # forecasts

## Part II:  Long-Lead Seasonal Forecasts

## Forecast Maps and Bulletins

- Each month, on the Thursday between the 15th 21st, CPC issues a set of 13 seasonal outlooks.
- There are two maps for each of the 13 leads, one for temperature and one for precipitation for a total of 26 maps.
- Each outlook covers a 3-month “season”, and each forecast overlaps the next and prior season by 2 months.
- Bulletins include: the prognostic discussion for the seasonal outlook over North America, and, for Hawaii.
- The monthly outlook is issued at the same time as the seasonal outlook. It consists of a temperature and precipitation outlook for a single lead, 0.5 months, and the monthly bulletin.
- All maps are sent to AWIPS, Family of Services and internet.

## Official 90 day T forecast

- _Official 90 day T forecast_

- _Minneapolis_
- Below: 40%
- Normal: 33%
- Above: 27%

- _Phoenix_
- Below: 05%
- Normal: 33%
- Above: 62%

- _Washington_
- Below: 33%
- Normal: 33%
- Above: 33%

## Seasonal Probability of Exceedance (POE) Forecast

## Multi-Agency Conference Call

- Friday Before Forecast Release

- Items Discussed:

- Participating Agencies:

**Verification of Previous Forecasts**
**Monitoring of Current Conditions (e.g. SST, Soil Moisture)**
**Discussion of Forecast Models from Various Agencies**

**Climate Prediction Center**
**International Research Institute for Climate Prediction**
**Climate Diagnostics Center**
**National Aeronautics and Space Administration**
**Scripps Institution of Oceanography**
**Pacific Marine Environmental Laboratory**
**Environmental Modeling Center**

## Final “Sanity Check”

## The End Result: U.S. Temperature Skill

- SS1= ((c-e)/(t-e))*100

- SS2= ((c+(1/3)*cl - e)/(t-e))*100

- Mean ss1

- Mean ss2

**0**

- _The End Result: U.S. Temperature Skill_

## The End Result: U.S. Precipitation Skill

- _The End Result: U.S. Precipitation Skill_

## The End

## Precipitation Categorization Scheme

- _Precipitation Categorization Scheme_

- Arid

- Semi-Arid

- Normal

## Conference Call “Centerpiece”