Operational and Statistical Prediction of Rapid Intensity Change. Mark DeMaria and Eric Blake, NCEP/NHC John Kaplan, AOML/HRD

Transcription

1 Operational and Statistical Prediction of Rapid Intensity Change Mark DeMaria and Eric Blake, NCEP/NHC John Kaplan, AOML/HRD

2 Outline Evaluation of NHC forecasts and deterministic models for rapid intensification cases Operational methods for anticipating rapid intensification The SHIPS Rapid Intensification Index

3 Hurricane Marie 2014 Aug UTC to Aug UTC

4 Distribution of 24 hr Intensity Changes Atlantic From Kaplan et al (2010) WaF

5 RI Verification Procedure Sample Operational Forecasts Tropical/Subtropical cases Land cases removed Four intensity change thresholds 20, 30, 40 and 50 kt Five forecast periods 0-24, 24-48, 48-72, 72-96, hr Forecast Techniques OFCL, DSHP, LGEM, GHMI, HWFI Question 1: Do techniques forecast RI? Question 2: How accurate are RI forecasts? Probability of Detection = % of observed RI cases correctly forecasted False Alarm Ratio = % of RI forecasts that were not RI cases

6 Percentage of AL Cases with RI

7 Percentage of EP Cases with RI

8 POD and FAR for 0-24 hr 30 kt Threshold Atlantic East Pacific

9 Main Tools for RI Forecasting at NHC SHIPS-RI Index 8 predictors used to estimate RI probabilities Global model predictions/fields Favorable characteristic upper-level patterns and/or the models showing sharp intensification. Microwave images Research has shown that a closed ring on the 37 ghz channel with other favorable environment factors greatly increases the chance of RI.

10 RI Guidance Hurricane Rick ( East Pacific) (output below is available in real-time) * EAST PACIFIC SHIPS INTENSITY FORECAST * * GOES DATA AVAILABLE * * OHC DATA AVAILABLE * * RICK EP /16/09 18 UTC * TIME (HR) V (KT) NO LAND V (KT) LAND V (KT) LGE mod ** 2009 E. Pacific RI INDEX EP RICK 10/16/09 18 UTC ** ( 30 KT OR MORE MAX WIND INCREASE IN NEXT 24 HR) 12 HR PERSISTENCE (KT): 20.0 Range:-20.0 to 35.0 Scaled/Wgted Val: 0.7/ MB SHEAR (KT) : 6.0 Range: 15.2 to 1.6 Scaled/Wgted Val: 0.7/ 0.8 D200 (10**7s-1) : 70.0 Range:-10.0 to Scaled/Wgted Val: 0.6/ 0.4 POT = MPI-VMAX (KT) : 96.7 Range: 46.6 to Scaled/Wgted Val: 0.6/ MB REL HUM (%): 79.4 Range: 64.0 to 88.0 Scaled/Wgted Val: 0.6/ 0.2 % area w/pixels <-30 C: 98.0 Range: 26.0 to Scaled/Wgted Val: 1.0/ 0.5 STD DEV OF IR BR TEMP : 8.3 Range: 35.4 to 2.7 Scaled/Wgted Val: 0.8/ 1.3 Heat content (KJ/cm2) : 46.8 Range: 4.0 to 67.0 Scaled/Wgted Val: 0.7/ 0.4 Prob of RI for 25 kt RI threshold= 78% is 6.8 times the sample mean(11.5%) Prob of RI for 30 kt RI threshold= 71% is 9.3 times the sample mean( 7.7%) Prob of RI for 35 kt RI threshold= 66% is 12.6 times the sample mean( 5.2%)

11 Rapid Intensification Hurricane Rick ( East Pacific) NHC FORECAST POSITIONS AND MAX WINDS INITIAL 16/2100Z 13.0N 100.0W 75 KT 12HR VT 17/0600Z 13.2N 101.3W 90 KT 24HR VT 17/1800Z 13.7N 103.3W 105 KT 36HR VT 18/0600Z 14.3N 105.8W 115 KT 48HR VT 18/1800Z 15.0N 108.1W 125 KT 72HR VT 19/1800Z 16.5N 111.5W 120 KT 96HR VT 20/1800Z 18.5N 113.0W 105 KT 120HR VT 21/1800Z 20.5N 113.0W 85 KT 70 kt 135 kt 24 hrs

12 Difficulty with Rapid Intensity Change First round of RI (intensification to Cat 1 hurricane) relatively well anticipated in official NHC forecasts Second more extreme instance of RI was not well forecast Rapid weakening after peak intensity not forecast well either

13 GFS SLP/200 mb winds Marie

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15 John Kaplan (NOAA/HRD), Mark DeMaria (NOAA/NHC), James Kossin (NOAA/NCDC), Christopher Rozoff (CIMSS), Charles Sampson(NRL), Christopher Velden (CIMSS), Joseph Cione (NOAA/ESRL/HRD), Jason Dunion (U. Miami/HRD), John Knaff (NOAA/NESDIS), Jeremy Solbrig (NRL), Jun Zhang (U. Miami/HRD), Jack Dostalek (CIRA), Jeffrey Hawkins (NRL), Evan Kalina (U. Colorado), Paul Leighton (NOAA/HRD) Acknowledgements: Financial support provided by the NOAA/OAR USWRP Joint Hurricane Testbed and NOAA/NESDIS GOES-R Proving Ground programs.

16 Background Deterministic forecasts of RI have generally been unreliable. Statistically based model for estimating the probability of RI for a 24-h lead time (i.e., t=0 to t=24-h) using SHIPS environmental predictors (SHIPS- RII) was developed and implemented operationally at the NHC in 2004 (Kaplan and DeMaria 2003). Discriminant analysis version of the SHIPS-RII that employed additional environmental and new inner-core GOES-IR predictors was subsequently developed and became operational at the NHC in 2008 (Kaplan et al. 2010). Recent research has been conducted to improve statistical RI prediction by developing enhanced versions of the SHIPS-RII, Logistic regression, Bayesian, and Consensus RI models (Rozoff and Kossin 2011) for lead times of 12-h, 24-h, 36-h and 48-h.

17 Predictors used in new enhanced SHIPS-RII Predictor Definition DV12 Previous 12-h intensity change (+) SHEAR hPA vertical shear from km radius with vortex removed (time-avg.) (-) D hPA divergence from km radius (time-avg.) (+) TPW Percent area with TPW < 45 mm within 500 km radius 90 up-shear (t=0 h) (-) PC2 Second principle component of GOES-IR imagery within 440 km radius (t= 0 h) (-) SDBT Std. dev. of km GOES-IR brightness temperatures (t= 0 h) (-) MPI Potential intensity (Current intensity maximum potential intensity) (time-avg.) (+) OHC Oceanic heat content (time-avg.) (+) ICDA Inner-core dry air predictor (time-avg.) (-) VMX0 Maximum sustained wind (t=0 h) (+)

18 SHIPS-RI Predictor Relative Weights Atlantic E. Pacific

19 Verification Methodology Cross-validated leave one-year out versions of each of the Atlantic and E. Pacific RI models (SHIPS, Bayesian, Logistic regression, Consensus) were derived for all RI thresholds for the 10-year sample. The new independent cross-validated RI models were rerun for all cases from utilizing the operational GFS forecast fields and NHC storm input data archived for that 10-year period. The cross-validated independent forecasts were verified for all tropical and subtropical over-water cases as determined based upon NHC best track data.

20 Skill of the probabilistic independent RI model rerun forecasts Atlantic E. Pacific

21 Reliability of the probabilistic consensus RI model rerun forecasts Atlantic E. Pacific

22 Sample consensus RI model Atlantic basin rerun forecasts Wilma (2005) Michael (2012)

23 Deterministic RI verification All operational model, NHC, and consensus RI model rerun forecasts were verified for a homogenous sample of over-water tropical and subtropical forecast cases for the period RI consensus model forecast probability cutoffs of ~3-3.5 times the climatological probability of RI used to predict RI determined based upon rerun forecasts following the methodology described in Kaplan et al (2010). Operational intensity model and NHC OFCL forecasts determined to predict RI if forecasted intensity > RI threshold for a given case.

24 Atlantic ( ) deterministic RI model forecast skill

25 E. Pacific ( ) deterministic RI forecast skill

26 Improvements in NHC OFCL RI forecast skill

27 Future statistical RI model improvements NHC Structural information (Carrasco et al. 2014) Lightning data (DeMaria et al. 2012) Microwave satellite data (Rozoff et al. 2014) New HFIP diagnostics Large-scale Aircraft data (Rogers et al. 2014) Consensus methods ECMWF version of RII Other statistical techniques Logistic regression, Bayesian

28 Extra slides

29 Percentile thresholds associated with the corresponding RI intensity change for the Atlantic/Eastern North Pacific basins RI thresholds ( ). RI threshold N NRI Probability of RI (kt) (%) / / / / / / / / / / / / / / / / / / / / /94.0

30 Sample Consensus RI model E. Pacific basin rerun forecasts Rick (2009) Flossie (2007)