# Presentation: 518005

## CPC Extended Range Forecasts

- Ed O’Lenic
- NOAA-NWS-Climate Prediction Center
- Camp Springs, Maryland
- _[ed.olenic@noaa.gov](http://www.cpc.ncep.noaa.gov/products/predictions/schedule.html)_
- 301-763-8000, ext 7528

## Outline – over-view

- Weather versus climate
- Current status of CPC’s forecast system
- Schematic of the forecast system/process
- Outlook schedules/formats/tools/process
- Verification
- Threats, heat wave, wind chill products

## WEATHER  vs.  CLIMATE 

**WEATHER  vs.  CLIMATE**** **

- Smooth curve = 30 year mean (climatology)

- Wildly oscillating curve = daily “weather”

- Subtracting the
- climatology and
- performing a 31-day
- running mean reveals
- the low-frequency
- signal or short-term
- climate variations we are
- trying to predict.

## CPC Forecast system schematic

## Forecast Process Schematic

- Dynamical model forecasts/multi-model ensembles

- Recent observations

- Historical observations..

- Verifications/Statistical tools Downscaling, Analogs, Composites

- WEB PAGES/AUTOMATED DATABASES
- Peer-reviews of the forecast tools and of the penultimate forecast via web/telephone conference with partners and through local discussions (map discussions,sanity check, conference calls, etc...)

- Forecaster-created or automated products

- Dissemination to public

## Z500 die off

## Six-to-Ten Day and Week 2 Outlooks and Week 2 Outlooks

## 6-10 DAY/WEEK 2 OUTLOOK SCHEDULE/LEADS

- Each day, CPC prepares and disseminates outlooks for 6-10 days (lead time of 5 days) and week 2 (days 8-14, lead time of 7 days).
- Each of these outlooks is accompanied by forecast maps of
- 1) 500 mb height and 500 mb height anomalies over the Northern Hemisphere, forecast maps of
- 2) surface temperature and
- 3) precipitation for the continental U.S. and Alaska and a single bulletin, FEUS40, giving a prognostic discussion for both forecasts and a table of state-by-state forecasts for each forecast.
- On Monday through Friday, including holidays, the outlooks are prepared by a
- 	forecaster who draws the maps, writes the bulletin and composes the table.
- On Saturday and Sunday only automated versions of the maps and the tables are
- 	disseminated.

## 6-10 day/week 2 Outlook Categories, Probabilities

- 6-10 day/week 2 outlooks are prepared for 5-day/7-day
- average temperature and total accumulated precipitation
- category.  Three categories are used (terciles). These are
- BELOW-,NEAR- and ABOVE-*normal*, for temperature, and
- BELOW-, NEAR- and ABOVE-*median* for precipitation.  The
- contours on the maps depict the TOTAL probability of the
- occurrence of the indicated category.   Contours of the
- climatological normals are also shown.

## Recent Changes to Procedures

- From 3 times/week to daily in October 2000
- Automated weekend forecasts from October 2000
- Percent probability format from October 2000
- Alaska and week 2 added October 2000
- Automated wind-chill product introduced Nov 2001
- Bias-corrected precipitation forecast tool and other improvements added in the fall of 2001

## 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

## 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, two surface maps and a single bulletin.

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

## Sample 6-10 day average T outlook

## Sample 6-10 day P outlook

## 6-10 day/week 2 Forecast Tools

- Examples of the variety of  tools used in preparing the 6-10
- Day and week 2 outlooks.
- These forecast tools consist of:
- 1.	Statistical: Klein, Neural Network, analogs, teleconnections, calibrated MRF precipitation
- 2.	Dynamical: hrMRF, MRF ensembles, ECMWF, dAVA, CDC calibrated MRF

## A Simple Calibration Scheme 

- 23 years of daily forecasts (1 forecast/day) out to week 2, October 1978-present (MRF T62)

- Operations:  Run a 15-member ensemble in real-time using the same model as is used to create the archive.

- Ensemble mean for 8-14 days

- Calculate anomalies using the 23-year model climatology (bias corrected)

- Assume the mean week 2 spread is determined by the error variance of the 23-years of forecasts.

- A Simple Calibration Scheme

- Climatology of model: mean, standard deviation, error variance

## Uncalibrated forecasts reliability

## Calibrated forecasts reliability

## ECMWF upper-air height forecasts, analog

## MRF Ensemble upper-air-height forecasts, analog

## Official 6-10 day 500 hPa forecast

## Teleconnections (TC)

- Definition:  Composite of those maps, for a calendar month, with largest + (top 10%) or – (bottom 10%) 500 hPa height at a specified space point from 1950-1999 (~150 maps).
- Forecasters compute TC on the major anomaly centers (base points) of 500 hPa forecast maps.  If there is a strong relationship between the base point centered at the largest anomaly, and distant points, the TC map will display large correlation values at the base point and at the distant centers.  If there is no strong historical relationship, only the correlations at the base point will be large.
- Weak TC indicate the pattern is probably transient and not as likely to be well predicted by the model as would a persistent (strong TC) pattern.

## Teleconnection on 500 hPa weighted mean anomaly center at 140W/53N(-)

## Composite of observed T, P anomalies associated with teleconnection on - 500 hPa anomaly at 53N 140W

## T prediction analog maps

## Week 2 forecast tools from CDC

## MRF Precipitation Bias Correction:  Week 2

## Z500 d+8 skill

## Z500 d+11 skill

## T850 d+8 skill

## T850 d+11 skill

## Official 8-14 day T, P forecast

- The final forecasts of temperature and precipitation.  The forecasters reasoning is given in the bulletin (next slide).

## 6-10 day Monthly Average Skill Scores

- 6-10 day Monthly Average Skill Scores

## U.S. Hazards Assessment

## Definitions of Threats

- Listed at left are the nominal definitions of threats.  Because prior conditions play a role in the impact of anomalies on the level of threat, the definitions listed are only guidelines, to be used along with knowledge of prior conditions, by the forecaster in assigning threats.
- Research is required to objectively determine thresholds for threats at a large number of locations.

## New medium range automated products

- CPC and MDL have collaborated to create new MOS-based
- products which are produced and disseminated automatically.
- Heat index outlooks for 6-10 and 8-14 days
- Wind-chill outlooks for 6-10 days
- Average temperature outlooks for 6-10 days

## Excessive Heat Outlooks

## Excessive Heat probabilities

## Wind-chill Outlooks

## Average T Outlook

## The End