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Using Tropical Cyclone Wind Speed Probabilities to Improve Public and Marine Text Forecasts

Module #1. Using Tropical Cyclone Wind Speed Probabilities to Improve Public and Marine Text Forecasts. Pablo Santos and Guy Rader WFO Miami, FL David Sharp and Matthew Volkmer WFO Melbourne, FL. “HURRICANE CONDITIONS EXPECTED.”. From the 2007 NOAA Hurricane Conference. PS/DS.

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Using Tropical Cyclone Wind Speed Probabilities to Improve Public and Marine Text Forecasts

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  1. Module #1 Using Tropical CycloneWind Speed Probabilities to ImprovePublic and Marine Text Forecasts Pablo Santos and Guy Rader WFO Miami, FL David Sharp and Matthew Volkmer WFO Melbourne, FL “HURRICANE CONDITIONS EXPECTED.” From the 2007 NOAA Hurricane Conference PS/DS

  2. Two Training Modules • Module #1: Concepts for Using Tropical Cyclone Wind Speed Probabilities to Generate Expressions of Uncertainty • Module #2: Applying Expressions of Uncertainty to the ZFP and CWF during Tropical Cyclone Wind Situations In Support of an Experimental Project for 2008

  3. Training Module (1 of 2) • Module #1: Concepts • Motivation • Overview and Background • Probability Concepts • Situational Thresholds • gridded inputs • Expressions of Uncertainty • unique expressions • text formatters • Future Plans

  4. Objectives • To better understand the shortcomings of deterministic-only wind speed forecasts during high impact weather events. • To gain a greater appreciation for the value of probabilistic wind speed information and how incremental probabilities can be used to improve certain text products. • To become familiar with the nine identified expressions of uncertainty and the unique situations that invoke them.

  5. Wind Speed Probabilities Interval Probabilities & Cumulative Probabilities PWS Cumulative – 64 knot

  6. Probability Definitions (A Quick Review) • Cumulative – The probability of sustained winds reaching or exceeding the specified wind speed threshold between the 00 hour forecast and a specified forecast hour. • Available in D2D and within the PWSAT# text product. • Individual (Interval) – The probability of sustained winds reaching or exceeding the specified wind speed threshold beginning during an individual 12 hour forecast period ending at the specified forecast hour (e.g., period of onset). • Not available in D2D, but within the PWSAT# text product. • Incremental –The probability of sustained winds reaching or exceeding the specified threshold during the 12 hour forecast period ending at the specified forecast hour. • Now available in D2D (across the SBN), but not within the PWSAT#. • These are the probabilities referenced throughout this presentation.

  7. Incremental Probabilities • Incremental –The probability of sustained winds reaching or exceeding the specified threshold during the 12 hour forecast period ending at the specified forecast hour. • Now available in D2D (across the SBN), but not within the PWSAT#. What do they look like?

  8. = EXAMPLE = 34 Knot (36 Hours) TC Wind Speed Probabilities on AWIPS-D2D (Incremental-form for 34-, 50-, and 64-knots) Hurricane Charley 2004 34 knot / 36 hour

  9. = EXAMPLE = 34 Knot (48 Hours) TC Wind Speed Probabilities on AWIPS-D2D (Incremental-form for 34-, 50-, and 64-knots) Hurricane Charley 2004 34 knot / 48 hour

  10. Proposed WFO Use(Item 42-05 from NOAA Hurricane Conference, 2005) • During potential high impact weather events such as tropical cyclones (TC), users not only demand our ‘best forecast’, but also require a corresponding expression of uncertainty for decision-making purposes. • Therefore, we are exploring the use of TC Wind Speed Probabilities to elevate the utility of official text products: • That is, to include situational expressions of uncertainty within the Zone Forecast Product (ZFP) and the Coastal Waters Forecast (CWF). • For WFOs, this effort crosses a major threshold for incorporating probabilistic data (other than PoP) within official National Weather Service forecast products.

  11. Point-n-Click Web Version FRANCES (ZFP)

  12. Rules for Formatters • The intent is to establish a set of rules for triggering enhanced wording which responsibly conveys wind speed uncertainties within text forecasts according to the temporal period. • This is accomplished through the Graphical Forecast Editor (GFE) and automated formatters by making appropriate use of the following grids sets: • Hazard Grids • Wind Grids • Tropical Cyclone 34 kt Wind Speed Probability Grids • Tropical Cyclone 64 kt Wind Speed Probability Grids • Initial development and testing was done during the 2005-06 seasons by WFOs MFL and MLB. The experimental effort was then expanded during the 2007 season to include a few more WFOs, with HGX playing a critical role. The good news is that more WFOs are being included for the 2008 season, with the Point-n-Click functionality also making its debut.

  13. Grid Set Descriptions • The Hazard Grids include Hurricane/Tropical Storm Warning/Watch grids as issued: • For coastal zones by NHC • For inland zones by WFO • For marine zones by WFO • The Wind Grids represent the sustained wind speed forecast as generated by the TCM Wind tool (from the latest NHC forecast), but with WFO value-added contributions for local effects (e.g., elevation, exposure, gap winds, etc.). • Again, the Tropical Cyclone Wind Probability Grids (as obtained through TPC) are the incremental-form probabilities for 34 knot and 64 knot winds. • The incremental probabilities for 50 knot winds are not needed for this application.

  14. Message Sensitivity (Fostering One Forecast Message) Text Formatters: Logic Hierarchy Note: Forecast Uncertainty implies appreciation for the inherent errors regarding the forecast track, intensity, and size of the tropical cyclone.

  15. Baseline Phraseology (The Nine Expressions of Uncertainty) • The *phrases are equivalent to imminent or ongoing conditions as • reflected in the 00-12 hour period simultaneously by the hazard, wind, and • probability grids. • The word EXPECTED is used in situations mainly during the Warning period, but is • also selectively used in the Watch period (e.g., Day 1 & 2, or out to period 4). • The word POSSIBLE is used during the extended period (e.g., Day 3 - 5), but is also • used in specific situations within Watch/Warning period. • Also, certain situations require compound phrases (e.g., when there is a Tropical • Storm Warning with a Hurricane Watch).

  16. Triggers (First Period: When conditions are IMMINENT or ONGOING) • For a given zone or zone combination, in order to consider a situation as being imminent or ongoing within the first period of the text forecast requires: • Tropical Storm (Hurricane) Warnings to be in effect…AND…maximum Wind • forecast to be greater than or equal to 34 knots (64 knots)...AND…the 34 knot • (64 knot) Probability to be greater than or equal to the PWS34 threshold • (PWS64 threshold). Note: Initial probability thresholds were empirically-determined; future refinements are likely. This is true for each temporal interval of the forecast.

  17. Triggers (Periods 1-4: When conditions are EXPECTED) • For a given zone or zone combination, invoking the wordEXPECTED for the specified period of the text forecast requires: • Tropical Storm (Hurricane) Warnings to be in effect…AND…maximum Wind forecast to be • greater than or equal to 34 knots (64 knots)…OR… • Tropical Storm (Hurricane) Warnings to be in effect…AND…maximum Wind forecast to be • greater than or equal to 25 knots (50 knots)…AND…the 34 knot (64 knot) Probability to be • greater than or equal to the PWS34 threshold (PWS64 threshold) according to the forecast • period.

  18. Triggers (Periods 1-10: When conditions are POSSIBLE) According to the situation, the word POSSIBLE can be invoked anytime throughout the five-day forecast, and is the qualifier most often used within the enhanced phrasing. Within the 00-48 hour forecast, if imminent/ongoing criteria are not met, or EXPECTED criteria are not met, the word POSSIBLE is used whenever the probability thresholds are exceeded for the given time period. In the extended (e.g., beyond 48 hours), an additional constraint of winds > 20 knots is imposed.

  19. Triggers (Periods 1-10: When conditions are POSSIBLE) • For a given zone or zone combination, invoking the wordPOSSIBLE for the specified period of the text forecast requires: • From the Hazard Grids Perspective…a Tropical Storm (Hurricane) Warning to be in effect • with maximum Wind and/or Probability criteria met, but criteria for imminent/ongoing conditions • or EXPECTED conditions not be met…OR… • Also From the Hazard Grids Perspective…a Tropical Storm (Hurricane) Watch to be in • effect with maximum Wind or Probability criteria met…OR… • From the Wind Grids Perspective…the maximum Wind to be greater than or equal to 25 • knots when there is also a Watch/Warning in effect…OR… • Also From the Wind Grids Perspective…the maximum Wind forecast to be greater than or • equal to 34 knots (64 knots), but Watches/Warnings not be in effect…OR… • From the Probability Grids Perspective…the 34 knot (64 knot) Probability to be greater than • or equal to the PWS34 threshold (PWS64 threshold) according to the forecast period, • regardless of whether there are Watches/Warnings in effect. In the extended periods, in addition to the probability threshold criteria, the forecast wind must also be 20 knots or greater.

  20. Hurricane Wilma (2005) Hazard Grids Input

  21. Algorithm Example Advisory Time: 20051023_2100 (First through Third Periods) WILMA (CWF) Wind Grids Input Contoured Wind Speeds 0-24 knots 25-33 knots 34-49 knots 50-63 knots 64+ knots

  22. Algorithm Example Advisory Time: 20051023_2100 (First through Third Periods) WILMA (CWF) Hurricane Wilma (CWF)

  23. Algorithm Example Advisory Time: 20051023_2100 (First through Third Periods) WILMA (CWF) Hurricane Wilma (CWF)

  24. Algorithm Example Advisory Time: 20051023_2100 (First through Third Periods) WILMA (CWF) Hurricane Wilma (CWF)

  25. Algorithm Example Advisory Time: 20051023_2100 (First through Third Periods) WILMA (CWF) Hurricane Wilma (CWF)

  26. Hurricane Charley - Update

  27. A Second Algorithm Example Advisory Time: 20040813_1500 (0-12 Hours – First Period) CHARLEY (ZFP) * Naples Morning Update Hurricane Charley (ZFP)

  28. A Second Algorithm Example Advisory Time: 20040813_1500 (0-12 Hours – First Period) CHARLEY (ZFP) * Naples Morning Update Hurricane Charley (ZFP)

  29. A Second Algorithm Example Advisory Time: 20040813_1500 (0-12 Hours – First Period) CHARLEY (ZFP) * Punta Gorda Hurricane Charley (ZFP)

  30. Current & Future Work • Conduct experiment during 2008 season • Generate case study examples from other locations and with an increasing variety of storms (real-time or archived) • Validate probability thresholds; perform ROC Diagram study • Evaluate consistency issues between the ZFP/CWF and their web page Point-n-Click counterparts • Evaluate consistency issues advisory to advisory • Compile experiences and share with the Tropical Cyclone Wind Team (present to NOAA Hurricane Conference - 2008) • Iterative Decision Points (considering user benefits) • Continue experimentally, implement officially, or discontinue • ZFP and CWF products • Click Point forecast web pages • Consider other applications (e.g., Point Forecast Matrices, etc.)

  31. Summary • This completes Module #1 • Please review Module #2 • Applying Expressions of Uncertainty to the ZFP and CWF during Tropical Cyclone Wind Situations Thank You !!!

  32. Tropical Cyclone Impacts Graphics David Sharp, Pablo Santos, Tom LeFebvre, Frank Alsheimer, and Tim Schott Threat Assessment Potential Impact DS/PS 2008

  33. Hazard >> Threat >> Impact • TC Hazardsinclude high wind, storm surge and tide, flooding rain, and tornadoes. • Coastal WFOs (participating in the experiment) execute TC Threat Assessment Tools once tropical cyclone watches or warnings are issued for their forecast area. These tools consider: • forecast magnitude of hazard • forecast uncertainty of hazard • Final output is in the form of TC Potential Impact Graphics which are posted to the web as an experimental service. • Depictions are valid for the duration of the event, locally, but updated with each successive advisory from NHC, to include updates from HPC and SPC. Inland Flooding Impact

  34. Potential Impact Graphics • The associated hazard is identified. • In context of event • The corresponding threat is quickly assessed through software applications and then delivered to the forecaster for limited editing. These SmartTools provide: • Automated first-guess fields on GFE • WFO forecaster expertise optionally applied • Output is converted to *.png graphics • The result is a simplified graphical expression that has been interpreted in terms of potential impact and provided to users via the web. • Color-coded graphics (and eventually grids) • Customer language • Locally calibrated definitions From the Practical Perspective: Inland Flooding Impact

  35. National Web Site (Participating Coastal WFOs – 2008) http://www.weather.gov/os/tropical/index.php

  36. Graphics & Definitions

  37. This is “Cool Stuff” !!! http://lucretia.srh.noaa.gov/coolstuff/tropical_graphics/index.php

  38. The High Wind Hazard

  39. High Wind - Tool Inputs 64 KTS Cumulative Probabilities Threat Assessment Deterministic & Probabilistic Gridded Input

  40. Deterministic Wind WFO Wind Grids • NHC Official Forecast • WFO Enhancements • Mesoscale interactions • Terrain altitude • Windward vs. Leeward • islands • mountains • Gap winds • Large inland lakes • And so on… Jeanne (04)

  41. Logic Summary - High Wind

  42. High Wind – Tool Interface Tropical Cyclone Wind Threat 42

  43. High Wind – Tool Interface Tropical Cyclone Wind Threat 43

  44. Potential Impact Graphic High Wind Impact

  45. Potential Impact Graphic (left) and NHC forecast (right) for Hurricane Charley 30 hours prior to landfall. Storm strengthened rapidly just prior to landfall and made landfall at Punta Gorda. The impact graphic shows that Tampa and Punta Gorda were both subject to an extreme impact. Both cities should have been preparing for a major hurricane! Run-to-Run Behavior Tampa Bay (A) vs. Punta Gorda (B) Hurricane Charley (04) A B 45

  46. Inland Wind Impacts Initial Output From TCWindThreat Tool Orlando Arcadia Punta Gorda From NOAA/HRD Hurricane Charley – 081304_18z_highwind

  47. Consistency & Continuity Hurricane Wilma (05) MLB MFL Initial output from tool. WilmaWindThreat 10/22/05 21z Minor tweaks by forecaster to handle slightly higher winds along the coast from KSC south. Matches up WFO to WFO as with other GFE elements. Potential Impact - Wind Potential Impact - Wind 47 Just over 36 hours from landfall on the SW Floridacoast

  48. The Surge and Tide Hazard

  49. Coastal Flooding - Tool Inputs Approach: Utilize gridded probabilistic and deterministic storm surge input for the Surge Threat tool much like the Wind Threat tool. 10% Exceedance Wilma (05) Deterministic (SLOSH composite max) Probabilistic (as developed by MDL) 49

  50. Logic Summary – Surge + Tide

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