Winter Weather Warning Decision Making Weather Workshop October 8, 2002 Jim Lee Chief, Fire and Public Weather Services Branch Office of Climate, Water, and Weather Services

October 8, Introduction WelcomeWelcome Achieving better winter weather forecasting performance, through:Achieving better winter weather forecasting performance, through: –Training –Better science & technology –Experience AgendaAgenda –Brief review of what’s new in policy –NWS Directives System –Future Plans

October 8, NWS Directives System NWS is at the end of transitioning from the WSOM to the NWS Directives SystemNWS is at the end of transitioning from the WSOM to the NWS Directives System NWS Directives System Vision:NWS Directives System Vision: –NWS policy development is efficient and effective –NWS policies are easily understood and accessed NWS Directives System basic building blocks:NWS Directives System basic building blocks: –Policy Directives –Procedural Directives (Instructions and Manuals) Regional SupplementsRegional Supplements

October 8, Winter Weather Directives NWS Policy Directive (NWSPD) 10-5, Public Weather ServicesNWS Policy Directive (NWSPD) 10-5, Public Weather Services –Defines the mission critical, high level public weather policy NWS Instruction (NWSI) , WFO Winter Weather Products SpecificationNWS Instruction (NWSI) , WFO Winter Weather Products Specification –Describes winter weather products issued by WFOs NWSI , National Winter Weather Products SpecificationNWSI , National Winter Weather Products Specification –Describes winter weather products issued by HPC NWS Directives Web Page: Directives Web Page:

October 8, NWSI : Issuance Criteria Defined Winter Storm Outlook:Winter Storm Outlook: –> 30% chance of a hazardous winter weather event exceeding local warning criteria in the next 3-to-5 days Winter Storm Watch:Winter Storm Watch: –> 50% chance of a hazardous winter weather event meeting or exceeding local warning criteria in the next 12 to 48 hours Winter Weather Warning and Advisories:Winter Weather Warning and Advisories: –> 80% chance of a hazardous winter weather event meeting or exceeding local warning criteria in the next 36 hours

October 8, Comfort and Growth Commensurate with science & technology, we need to go beyond our “comfort zone” to growCommensurate with science & technology, we need to go beyond our “comfort zone” to grow –Yes, there will be failure; however, anticipate learning from failure

October 8, Catalog of Event Specific Products Winter Weather WarningsWinter Weather Warnings –Blizzard Warning –Heavy Snow Warning –Ice Storm Warning –Heavy Sleet Warning –Lake Effect Snow Warning –Winter Storm Warning Winter Weather Advisories –Snow and Blowing Snow Advisory –Snow Advisory –Freezing Rain Advisory –Sleet Advisory –Lake Effect Snow Advisory –Winter Weather Advisory

October 8, Winter Storm Warning Issuance Criteria “Winter Storm Warning”: A winter weather event having:“Winter Storm Warning”: A winter weather event having: –More than one predominant hazard: Snow and sleetSnow and sleet Sleet and iceSleet and ice Snow, sleet and iceSnow, sleet and ice Heavy snow and blowing snow - NewHeavy snow and blowing snow - New –At least one of the precipitation elements meets or exceeds locally defined 12 and/or 24 hour warning criteria –When the precipitation type cannot be determined

October 8, Minimum Forecast Snowfall Criteria Issuance criteria based on the average value of the forecast snowfall range and not high endpointsIssuance criteria based on the average value of the forecast snowfall range and not high endpoints Heavy Snow Warning Criteria (Inches) Forecast Range (Inches) Average (Inches) Issue Warning? 4 3 to 5 4Yes 2 to 4 3No 8 5 to Yes (round to 8) 4 to 8 6No

October 8, Future Plans AMS Policy Statement issued January 2002AMS Policy Statement issued January 2002 –“Enhancing Weather Information with Probability Forecasts” Local Winter Weather Warning/Advisory Criteria Program, based on:Local Winter Weather Warning/Advisory Criteria Program, based on: –Snowfall rate, and/or –Time of occurence

October 8, Winter Weather Science and Technology Infusion Plan Team Composition Sam Contorno – NWS/OSTSam Contorno – NWS/OST Mark Tew – NWS/OCCWSMark Tew – NWS/OCCWS Marty Ralph – OAR/ETLMarty Ralph – OAR/ETL Jack Dostalek – NESDIS/CIRAJack Dostalek – NESDIS/CIRA John Cortinas – OAR/NSSL/CIMMSJohn Cortinas – OAR/NSSL/CIMMS Andy Edman – NWS/WR SSDAndy Edman – NWS/WR SSD Paul Sisson – NWS/WFO BTVPaul Sisson – NWS/WFO BTV Jeff Waldstreicher – NWS/ERJeff Waldstreicher – NWS/ER Peter Manousos – NWS/NCEP/HPCPeter Manousos – NWS/NCEP/HPC Allen White – OAR/ETLAllen White – OAR/ETL Paul Neiman – OAR/ETLPaul Neiman – OAR/ETL Paul Stokols – NWS/OCCWSPaul Stokols – NWS/OCCWS

October 8, Winter Weather DRAFT Expected Results/Outcomes Existing Current Skill FY07 Goal FY12 Target Winter Storm Warning Lead Time 13 Hours 15 Hours 18 Hours Winter Storm Warning POD 90%90%93% AccuracyProposed Current Skill FY07 Goal FY12 Target Winter Storm Warning FAR 27%26%24% On Track Low Risk High Risk High Level National Benefits

October 8, Winter Weather DRAFT Key S&T Solutions DA/NWP Observations Forecast Techniques Dissemination Enabling Technologies Training Dual PolarizationTargeted Observations 8km WRFAdvanced Ensembles Weather Event Simulator Meso Snowband Technique Deployment OTE DTE R&D

October 8, Future Plans (cont.) Winter Weather Experiment (WWE) IIWinter Weather Experiment (WWE) II –Coordinated by OCWWS, NCEP, Eastern and Central Region Headquarters –Goal: Improve winter weather products and services provided for the public Evaluate HPC’s role in facilitating a collaborative set of guidance productsEvaluate HPC’s role in facilitating a collaborative set of guidance products Evaluate the performance of EMC’s SREF during winter eventsEvaluate the performance of EMC’s SREF during winter events –HPC is striving to be the coordination leader or National Center for Winter Storms (e.g., SPC, TPC)

October 8, Future Plans (cont.) WWE II (winter )WWE II (winter ) –All 23 ER WFOs and 8 CR WFOs will work with HPC to test and evaluate the concept this winter –HPC will prepare three graphical products –Verification statistics of pre vs. post chat sessions

October 8, Summary Issuing watches, warnings, advisories and statements is the core mission of the NWSIssuing watches, warnings, advisories and statements is the core mission of the NWS Go back to your WFO and use these materials to trainGo back to your WFO and use these materials to train Take time for the course evaluationsTake time for the course evaluations Thanks for taking the time to attend!Thanks for taking the time to attend! x x107