COAPS Workshop March 9-11, 2004 WFO Site Specific Seasonal Outlook Product Victor Murphy Southern Region Climate Service Program Manager Nicole Kempf Nicole Kempf Climate Services Focal Point WFO Tulsa

COAPS Workshop March 9-11, 2004 Outline What is Downscaling anyway? What is Downscaling anyway? Probability of Exceedance (POE) Probability of Exceedance (POE) Data Used Data Used Error Error Trend Adjustment Trend Adjustment Webpage Webpage Time commitment and current status Time commitment and current status

COAPS Workshop March 9-11, 2004 What is downscaling? Downscaling is the transformation from a large-scale feature to a small-scale one, not necessarily of the same kind. Downscaling is the transformation from a large-scale feature to a small-scale one, not necessarily of the same kind. A downscaled forecast is one that has been defined in more detail for a particular location from a forecast for a larger area. A downscaled forecast is one that has been defined in more detail for a particular location from a forecast for a larger area.

COAPS Workshop March 9-11, 2004 What is downscaling…cont. In this case, we are downscaling the Climate Prediction Center (CPC) forecast for a mega climate division (CD) to a specific station within a CWA. In this case, we are downscaling the Climate Prediction Center (CPC) forecast for a mega climate division (CD) to a specific station within a CWA. Therefore, we are only ‘tweaking’ the CPC forecast…not making a brand new forecast Therefore, we are only ‘tweaking’ the CPC forecast…not making a brand new forecast Method developed at CPC by Method developed at CPC by Barnston, Unger, and He

COAPS Workshop March 9-11, 2004 What is downscaling…cont. Initially, this can be required for LCD sites Initially, this can be required for LCD sites –Additional sites can be added at the WFO discretion Can be done for any station in the country that has monthly data from (not just Southern Region) Can be done for any station in the country that has monthly data from (not just Southern Region)

COAPS Workshop March 9-11, 2004 Probability of Exceedance The probability that a certain value of interest would be exceeded given a forecast shift in a distribution. The probability that a certain value of interest would be exceeded given a forecast shift in a distribution. Or in other words, the probability that the actual temperature will exceed a particular temperature Or in other words, the probability that the actual temperature will exceed a particular temperature ons/long_range/lead01/poe_index.html ons/long_range/lead01/poe_index.html ons/long_range/lead01/poe_index.html ons/long_range/lead01/poe_index.html

COAPS Workshop March 9-11, 2004 Probability of Exceedance…cont.

COAPS Workshop March 9-11, 2004 Probability of Exceedance…cont. CPC already downscales for 65 select cities CPC already downscales for 65 select cities citydir/citydict.txt citydir/citydict.txt citydir/explanation_ctydf.html citydir/explanation_ctydf.html

COAPS Workshop March 9-11, 2004 Data –CPC used when downscaling for the select cities Need data for both the mega CD and the station Need data for both the mega CD and the station CD data retrieved from CPC website CD data retrieved from CPC website Station data retrieved from NCDC Station data retrieved from NCDC

COAPS Workshop March 9-11, 2004 Data…cont. Seasonal Average Mean Temperature Seasonal Average Mean Temperature –Season – consecutive 3 month periods (i.e. JFM, FMA, MAM, AMJ, MJJ, etc) –Mean – the daily mean temperature average for a month (found on F-6) –Average – must apply weight to each month Ex. JFM: (Tjan * 31 + Tfeb * 29 + Tmar * 31)/91 Ex. JFM: (Tjan * 31 + Tfeb * 29 + Tmar * 31)/91

COAPS Workshop March 9-11, 2004 Data…cont. CPC also makes POE forecasts for precipitation and degree days (heating and cooling) CPC also makes POE forecasts for precipitation and degree days (heating and cooling) CPC only makes downscaled temperature and degree day (heating and cooling) forecasts for the select cities CPC only makes downscaled temperature and degree day (heating and cooling) forecasts for the select cities WFOs will only be downscaling for temperature in the immediate future WFOs will only be downscaling for temperature in the immediate future

COAPS Workshop March 9-11, 2004 CPC Mega Climate Divisions (CD) Tulsa

Mega Climate Divisions

COAPS Workshop March 9-11, 2004 Mega CD vs. Station Develop a regression equation between the mega CD and the station Develop a regression equation between the mega CD and the station Plot the seasonal average mean temp from Plot the seasonal average mean temp from –x-axis = CD temp –y-axis = Station temp

COAPS Workshop March 9-11, 2004 Mega CD vs. Station…cont.

COAPS Workshop March 9-11, 2004 Summer: R 2 = Winter: R 2 = 0.76 Synoptic-scale systems Meso- /storm- scale systems WHY?

COAPS Workshop March 9-11, 2004 Error At least as great as the CPC POE forecast error At least as great as the CPC POE forecast error Uncertainty increases as correlation between the mega CD and station decreases Uncertainty increases as correlation between the mega CD and station decreases A lot of uncertainty with precipitation A lot of uncertainty with precipitation

COAPS Workshop March 9-11, 2004 Trend Adjustment Weights the slope and intercept of the regression equation to the last decade Weights the slope and intercept of the regression equation to the last decade –Past 10 years = CPC Optimal Climate Normal Cold decades followed by warm decades can create a bias Cold decades followed by warm decades can create a bias –This is more pronounced between dry and wet decades – A way of adjusting for urbanization

COAPS Workshop March 9-11, 2004 Trend Adjustment…cont. Tstation – Tcd (ºF)

COAPS Workshop March 9-11, 2004 Webpage wnscale/climfcst.php wnscale/climfcst.php wnscale/climfcst.php wnscale/climfcst.php Uses.php to create webpage Uses.php to create webpage –Each office up-loads graphics and a text file (per downscaled station) to the regional server and webpage is created by user input

COAPS Workshop March 9-11, 2004 Time Commitment Downscaling to be done by the Climate Services Focal Point (CSFP) Downscaling to be done by the Climate Services Focal Point (CSFP) –An assistant CSFP and/or another person should also be trained Takes about ½ hour or less per station (once proficient) for the data Takes about ½ hour or less per station (once proficient) for the data Another ½ hour or less per station to beautify the charts for the webpage Another ½ hour or less per station to beautify the charts for the webpage

COAPS Workshop March 9-11, 2004 Time Commitment…cont. CSFP will be given a template and step- by-step instructions CSFP will be given a template and step- by-step instructions Will be completed for the selected stations once per month, within 7 days of the issuance of the CPC product Will be completed for the selected stations once per month, within 7 days of the issuance of the CPC product –CPC product issued on the 3 rd Thursday of each month at 8:30 am May need to do verification/analysis to see how well it works May need to do verification/analysis to see how well it works

COAPS Workshop March 9-11, 2004 Current Status Experimental product with a Product Description Document (PDD) is available on the WFO TSA webpage. Experimental product with a Product Description Document (PDD) is available on the WFO TSA webpage. Still seeking feedback from experts in this field for tweaks to the templates and method. Still seeking feedback from experts in this field for tweaks to the templates and method. Trying to identify our customers. Trying to identify our customers. Trying to create/package a product that can be easily used and understood by our customers. Trying to create/package a product that can be easily used and understood by our customers.

COAPS Workshop March 9-11, 2004 Current Status…cont. Awaiting feedback on current experimental product from CPC, NWSH CSD, other Regions, customers. Awaiting feedback on current experimental product from CPC, NWSH CSD, other Regions, customers. Will provide training to other SR CSFP as needed. Will provide training to other SR CSFP as needed. NWSH timeline is for local climate products to be downscaled from CPC forecast products by the end of FY05. NWSH timeline is for local climate products to be downscaled from CPC forecast products by the end of FY05.

COAPS Workshop March 9-11, 2004 Sample of Current Product

Sample of Current Product Probability to go above Temperature Probability to stay below 20%61.8 °F80% 40%60.8 °F60% 59.8 °F40% 80%58.8 °F20%

COAPS Workshop March 9-11, 2004 Any questions or comments?