Forecast Capability for Early Warning: CPC Products, Plans and Perspective Jon Gottschalck1 and Augustin Vintzileos2 1 Operational Prediction Branch NOAA / NWS / Climate Prediction Center 2 Univ. of Maryland Earth System Science Interdisciplinary Center NIHHIS Workshop, July 13 2016 El Paso, TX Outline: 1. Review of current CPC heat related products and services 2. Status of experimental Week-2 excessive heat event forecast tools 3. Perspective on excessive heat predictions beyond Week-2

Current Heat Related Products (1) Much above normal temperatures Expectations that temperatures will approach or exceed those representing the top 1/8 of historical range (2) Excessive heat Expectations that the combined effects of temperature and humidity may reach heat indices greater than 105F

Current Heat Related Products Systematically migrating current deterministic outlook to probabilistic form for Days 8-14 Better and more frequent lead time for potential low probability, but high impact events Slight, moderate or high risk highlighted regions

Current Heat Related Products Example outlook Days 6-10 and 8-14 maximum heat index (HI) outlook Released daily from April 1st through September 30th Dashed contours depict threshold for the above normal tercile maximum heat index Shading represents the probability that this threshold will be exceeded during period Other information available in this outlook suite includes: 1. Outlook maps for probabilities for max HI exceeding 90F, 95F, 100F, 105F, 110F,115F 2. Probabilities for mean HI exceeding 85F, 90F, or 95F for 3 days, 2 days or 1 day

Week-2 Excessive Heat Event Tools Work led by Augustin Vintzileos – University of Maryland ESSIC Development of tools to better inform the Week-2 U.S. Hazards Outlook and investigate what may be possible at Week 3-4 leads Excessive heat days are defined based on heat index and an excessive heat event is defined as at least two consecutive days exceeding a given percentile threshold (90%, 95%) Variation by season and location are included in the metric Tools will allow better temporal resolution of information and use the latest state of the art datasets Internal evaluation of these new tools are being conducted by forecasters at CPC during the summer of 2016

Week-2 Excessive Heat Event Tools Probability of excessive heat event exceeding the 95th percentile Start day in Week-2 of excessive heat event Excessive heat event duration in days

Week 3-4 Information and Plans Experimental since September 2015 Probability of two week mean temperatures being above or below normal

Week 3-4 Information and Plans The Office of Science and Technology Policy (OSTP) has funded work at CPC Explore and document the scientific basis for excessive heat event outlooks at Weeks 3-4 Planned work includes (1) extension of ongoing Week-2 methods and (2) investigation of statistical and hybrid methods Goal is to work toward an experimental Week 3-4 excessive heat outlook 7/1-7/15 Excessive Heat Event (HI > 95th percentile) High Risk (60%) Moderate Risk (40%) Slight Risk (20%)

Seasonal Excessive Heat Predictability? CPC prepares seasonal temp outlooks Outlooks are for above, below or near average categories of mean 3-month temperature No excessive heat event information operationally prepared Climatology Outlook shift

Seasonal Excessive Heat Predictability? Excessive heat prediction information (character of the season or characteristics within the season) is an area of active research # extreme days within season; Hamilton et al. (2012); Pepler et al. (2015) Monthly/seasonal extremes; Becker et al. (2013)

Summary CPC produces operational outlooks targeting excessive heat which includes information as part of the U.S. Hazards Outlook and Week-2 heat index products CPC developing improved forecast tools targeting excessive heat events in Week-2 to support U.S. Hazards Outlook CPC has funding support for research to work towards the development of a prototype excessive heat event outlook for the Week 3-4 period if science supports Prediction of seasonal excessive heat information is an area of active research

Thank you for your attention Comments or questions? Jon.Gottschalck@noaa.gov?

Prospects for Subseasonal Heat Predictions Predictable, slow varying, climate oscillations such as tropical variability (e.g. MJO) Modulate the probability of occurrence of extreme weather events Modulate probability of occurrence of critical impacts including the heat- health relationship An important example: The Madden Julian Oscillation (MJO) can impact the pattern of high and low pressure in the Extratropics and can result in high impact events Courtesy: Augustin Vintzileos – University of Maryland ESSIC