storm prediction center forecast and guidance information for high-impact hazardous weather support...

Download Storm Prediction Center Forecast and Guidance Information for High-Impact Hazardous Weather Support Where Americas Climate and Weather Services Begin David

If you can't read please download the document

Post on 20-Jan-2016

212 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Storm Prediction Center Forecast and Guidance Information for High-Impact Hazardous Weather Support

    David BrightNOAA/NWS/Storm Prediction CenterScience Support BranchNorman, OK

    All Hazards Workshop6-7 February 2008Memphis, TNWhere Americas Climate and Weather Services Begin

  • Nine NWS National Centers

  • STORM PREDICTION CENTER MISSION STATEMENT The Storm Prediction Center (SPC) exists solely to protect life and property of the American peoplethrough the issuance of timely, accurate watch and forecast products dealing with tornadoes, wildfires and other hazardous mesoscale weather phenomena. MISSION STATEMENT The Storm Prediction Center (SPC) exists solely to protect the life and property of the American peoplethrough the issuance of timely, accurate watch and forecast products dealing with hazardous weather phenomena.

  • Hail, Wind, TornadoesExcessive rainfallFire weather Winter weatherSTORM PREDICTION CENTER HAZARDOUS PHENOMENA

  • Outline

    The SPCs Hazardous Weather ProgramForecasts Available on the SPC WebsiteCategorical and ProbabilisticGuidance Available on the SPC WebsiteMesoscale objective analysisShort-range ensemble guidanceAdditional datasetsData Available on the SPC WebsiteMesoanalysis archiveSevere weather events pageReportsForecast product archiveSummary

  • Framework for uncertaintyDecision making in uncertain environmentsSubjectivePrecise descriptions (quantitative)

  • Hazardous Weather Forecasting The Challenge: High impact events often occur on temporal and spatial scales below the resolvable resolutions of most observing and forecasting systems Key premise: We must use knowledge of the environment and non-resolved processes to determine the spectrum of possible hazardous weather, where and when it may occur, and how it may evolve over time

  • Hazardous Weather ForecastingObservational data and diagnostic toolsKey input for short-term prediction, i.e., NowcastBut high-impact weather events typically occur on scales smaller than standard observational data Environment not sampled sufficiently to resolve key fields (especially 4D distribution of water vapor)Model forecastsSupplement observational data in short term Increasing importance beyond 6-12 hr Typically do not resolve most severe phenomena NWP errors are related to both analysis errors and numerics/physics errors Recognize the inherent uncertainty and address it through probabilistic or confidence-based products

  • The Evolution of the ForecastNational Academy of Sciences report (2006):

    Uncertainty is a fundamental characteristic of weather, seasonal climate, and hydrological prediction, and no forecast is complete without a description of its uncertainty.

    As forecast skill has increased in recent years, forecasts have become an important component of everyday and hazardous-weather decision making for many segments of society and the U.S. economy.

    The entire enterprise should take responsibility for providing products that effectively communicate forecast uncertainty information.Source: Completing the Forecast http://www.nap.edu/catalog/11699.htmlNCEP Strategic Plan: Improve the users decision-making capabilities by including levels of forecast uncertainty in products and services.

  • The Evolution of the Forecast: 200815 years experience now in ensemble prediction in the USSteady progress in making ensemble guidance more useful and skillful (and available!)Increasing penetration of ensemble guidance into generation of high-impact forecasts, e.g., severe-storm forecasts, winter and fire weather.Many WFOs and National Centers beginning to issue probabilistic or uncertainty forecastsThe system is evolving the public and mass communication sources toward probabilistic thinkingMany NWS products still largely deterministic

  • Forecast Needs Vary from User to User So whats the deal with all this uncertainty? What can I do with a 10% chance of rain?Just tell me if its going to rain or not.

    They would if they could, my friend! But considering uncertainty information makes deterministic forecasts better, and adds value for some decision makers.

  • NWP models...All forecasts contain errors that increase with timeDoubling time of small initial errors ~1 to 2 daysMaximum large-scale (synoptic to planetary) predictability ~10 to 14 daysEnsemblesA collection of models that provide information on the range of plausible forecasts and extend predictabilityIncreasing in popularityRequires tools to view the large number of models using a slightly different approach (statistical)

    Weather forecasting: Its impossible to be deterministically correct all of the time!

  • Examples of Expressing UncertaintyAlthough not quantified,AFDs express forecastconfidence and uncertainty

  • Examples of Expressing UncertaintyFrom WFO Milwaukee/Sullivan

  • Many examples of Uncertainty Products

  • Probabilistic Forecasting at the SPCSevere Convective WeatherOutlooksWatches

  • Convective OutlooksCategorical Forecast Characterizes the overall threat through a single deterministic forecast

  • CONVECTIVE OUTLOOKSCategorical and Probabilistic: Operational through Day 8

    Tornado (Hatched area 10% > EF2)WindHail (Hatched area 10% > 2)Probabilistic forecasts provides additional information on confidenceProbability of severe event within 25 miles of a point

  • Verification of Probabilistic OutlooksHail (Initial Day 1, 2006)Significant hail forecast (hatched area)

    Chart5

    4.209.6

    12.9100

    20.9

    32.9

    27.9

    60.4

    83.3

    9.6

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Hail Reliability (2006 Final)

    Sheet1

    FCSTHailFCSTWindFCSTTor

    54.254.321.500

    1512.91512.754.7100100

    2520.92516.7108.8

    3032.93024.61514.3

    3527.93517.73045.5

    4560.44548.56040

    6083.3

    SIG109.6108107

    Sheet1

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Hail Reliability (2006 Final)

    Sheet2

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Wind Reliability (2006 Final)

    Sheet3

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Tornado Reliability (2006 Final)

  • Verification of Probabilistic OutlooksWind (Initial Day 1, 2006)

    Chart6

    4.308

    12.7100

    16.7

    24.6

    17.7

    48.5

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Wind Reliability (2006 Final)

    Sheet1

    FCSTHailFCSTWindFCSTTor

    54.254.321.500

    1512.91512.754.7100100

    2520.92516.7108.8

    3032.93024.61514.3

    3527.93517.73045.5

    4560.44548.56040

    6083.3

    SIG109.6108107

    Sheet1

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Hail Reliability (2006 Final)

    Sheet2

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Wind Reliability (2006 Final)

    Sheet3

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Tornado Reliability (2006 Final)

  • Verification of Probabilistic OutlooksTornado (Initial Day 1, 2006)Significant tornado forecast (hatched area)You can effectively gauge the likelihood of significant tornadoes within each watch

    Chart7

    1.507

    4.7100

    8.8

    14.3

    45.5

    40

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Tornado Reliability (2006 Final)

    Sheet1

    FCSTHailFCSTWindFCSTTor

    54.254.321.500

    1512.91512.754.7100100

    2520.92516.7108.8

    3032.93024.61514.3

    3527.93517.73045.5

    4560.44548.56040

    6083.3

    SIG109.6108107

    Sheet1

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Hail Reliability (2006 Final)

    Sheet2

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Wind Reliability (2006 Final)

    Sheet3

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Tornado Reliability (2006 Final)

  • Severe Weather WatchesProbabilistic Table (All watches are not created equal) Use the probabilities to refine the specific threat within the watch and gauge forecaster confidence in the specific convective hazards

  • Verification of Watch ProbabilitiesTwo or More Tornadoes (2006)

    Chart8

    10

    6100

    13

    18

    30

    42

    46

    71

    100

    100

    100

    Truth

    Forecast (%)

    Observed (%)

    Two-Tor Watch (2006 Final)

    Sheet1

    FCSTHailFCSTWindFCSTTorFcstSigTorFcst2Tor

    54.254.321.5005451

    1512.91512.754.7100100107106

    2520.92516.7108.820132013

    3032.93024.61514.330313018

    3527.93517.73045.540474030

    4560.44548.5604050575042

    6083.360676046

    SIG109.610810770677071

    80100

    90100

    100100

    Sheet1

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Hail Reliability (2006 Final)

    Sheet2

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Wind Reliability (2006 Final)

    Sheet3

    Truth

    Siggy

    Forecast (%)

    Observed (%)

    Tornado Reliability (2006 Final)

    Truth

    Forecast (%)

    Observed (%)

    SigTor Watch (2006 Final)

    Truth

    Forecast (%)

    Observed (%)

    Two-Tor Watch (2006 Final)

  • Verification of Watch ProbabilitiesOne or More Significant Tornadoes (2006)> EF2You can effectively gauge the likelihood of significant tornadoes within each watch

    Chart9

    40

    7100

    13

    31

    47

    57

    67

    67

    Truth

    Forecast (%)

    Observed (%)

    SigTor Watch (2006 Final)

    Sheet1

    FCSTHailFCSTWindFCSTTorFcstSigTorFcst2Tor

    54.

Recommended

View more >