Storm-Scale Ensemble Forecast Experiment - Fort Worth Tornadic Storm Case Fanyou Kong1 and Kelvin Droegemeier1,2 1Center for Analysis and Prediction of Storms, 2School of Meteorology, The University of Oklahoma
Domain Setting 24km (238x150) 6km (180x180) 3km (180x180)
Ensemble perturbation method Four SLAF (scaled-lagged average forecast) members: s1, s2; s3, s4 perturbations between previous ARPS forecasts (P1,P2) and current analysis are ± to the analysis One control member (regular ARPS run): cntl
24 km ensemble cntl P1 s1 s2 P2 s3 s4 6 km ensemble 3 km ensemble 3/28/2000 3/29/2000 00Z 06Z 12Z 18Z 00Z 06Z 24 km ensemble 18-hr cntl 24-hr P1 s1 s2 30-hr P2 s3 s4 6 km ensemble 12-hr rad, sat (P1 – cntl) (P2 – cntl) 3 km ensemble 22Z 8-hr rad, sat
12hr accumulate rainfall ARPS ETA
3-hr rainfall from 24 km ensemble cntl mean spread
Domain average spread from 24 km ensemble
Domain average spread from 24 km ensemble
3-hr rainfall from 24 km ensemble cntl s1 s2 s4 s3
3-hr rainfall probability from 24 km ensemble
500 hPa Height from 24 km ensemble mean spread
Sea Level Pressure from 24 km ensemble mean spread
Surface Temperature from 24 km ensemble mean spread
6 km ensemble
24 km ensemble P1 P2 6 km ensemble cntl s1 s2 s3 s4 3/28/2000 3/29/2000 00Z 06Z 12Z 18Z 00Z 06Z 24 km ensemble 18-hr 24-hr P1 30-hr P2 6 km ensemble 12-hr cntl rad, sat s1 (P1 – cntl) s2 s3 (P2 – cntl) s4
1-hr rainfall from 6 km ensemble cntl mean spread
Domain average spread from 6 km ensemble
Domain average spread from 6 km ensemble
1-hr rainfall from 6 km ARPS ensemble cntl s3 s4 mean
1-hr rainfall probability from 6 km ensemble
1-hr rainfall probability from 6 km ensemble
Hourly accumulate rainfall (mean vs obs)
Hourly accumulate rainfall (probability vs obs) Prob ≥ 0.1 in
3 km ensembles Test different ways to form IC/BC for individual members Evaluate ensemble analyses and products suitable for storm-scale EF Assess value of storm-scale EF
24 km ensemble P1 P2 6 km ensemble 3 km ensemble cntl s1 s2 s3 s4 3/28/2000 3/29/2000 00Z 06Z 12Z 18Z 00Z 06Z 24 km ensemble 18-hr 24-hr P1 30-hr P2 6 km ensemble 12-hr 3 km ensemble 8-hr cntl (method one & two) rad, sat 22Z s1 (P1 – cntl) s2 s3 (P2 – cntl) s4
3 km Ensembles – Method One Initiate at 22Z March 28 Control run from 6km cntl s1/s2 using perturbation between 24km P1 and control, s3/s4 using perturbation between 24km P2 and control Run ADAS only once (control run), with NIDS and sat data Explicit microphysics
Composite reflectivity from 3km cntl (initiate at 22Z)
radar cntl
Method One s1 s3 s2 s4
Method One s1 s3 s2 s4
3 km Ensembles – Method Two Initiate at 22Z March 28 Control run from 6km cntl s1/s2 using perturbation between 24km P1 and control, s3/s4 using perturbation between 24km P2 and control Run ADAS for each member, with NIDS and sat data Explicit microphysics
Method Two s1 s3 s2 s4
Method Two s1 s3 s2 s4
Surface reflectivity (method two) mean spread
Surface reflectivity probability (method two) ≥ 35 dBZ ≥ 45 dBZ
Hourly rainfall (method two) s1 s3 obs s2 s4
Hourly rainfall probability from 3km ensemble (method two)
3 km Ensembles – Method Three Initiate at 23Z March 28 Control run from 6km cntl s1/s2 using perturbation between 24km P1 and control, s3/s4 using perturbation between 24km P2 and control Run ADAS for each member, with NIDS and sat data Explicit microphysics
Composite reflectivity from 3km cntl (method three)
Model reflectivity vs radar cntl radar
Model reflectivity vs radar
Model reflectivity vs radar
Model reflectivity vs radar
Model reflectivity vs radar
Model reflectivity vs radar mean radar
Surface reflectivity from 3km ensemble (method three) cntl s3 s4 mean
Surface reflectivity probability (method three) ≥ 35 dBZ ≥ 45 dBZ
Surface reflectivity probability (method three) radar ≥ 35 dBZ
Hourly rainfall from 3km ensemble (method three) cntl s3 s4 mean
Hourly rainfall probability from 3km ensemble (method three)
Hourly rainfall probability from 3km ensemble (method three)
3 km Ensembles – Method Four Initiate at 23Z March 28 Control run from 6km cntl s1/s2 using perturbation between 6km 12Z and control, s3/s4 using perturbation between 6km 06Z and control Run ADAS for each member, with NIDS and sat data Explicit microphysics
Surface reflectivity probability (method four) radar ≥ 35 dBZ
Hourly rainfall probability from 3km ensemble (method four)