SREF Applications at AWC Dr Steverino Silberberg Aviation

SREF Applications at AWC Dr. Steverino Silberberg Aviation Weather Center May 13, 2008 4 th Ensemble Users Workshop

Aviation SREF Algorithms n n AWC-developed Externally-developed n RUC-based deterministic/ensemble guidance n n icing (CIP, FIP), turb (GTG), RUC conv prob Collaboration n AWC-EMC (Binbin Zhou, Jun Du) AWC-SPC (David Bright) AWC-GSD (RUCsters: Stan Benjamin, Steve Weygandt)

Aviation-Specific SREF Guidance n Flight Restriction (Ceiling/Visibility) n n n Ceiling (4500’, 3000’, 2000’, 1000’, 500’, <500’, mean, cloud top) Visibility (5, 3, 1, 0. 5 st mi) VFR (>3000’ and > 5 st mi) MVFR (1000’<ceiling 3000’; 3 vis 5 st mi) IFR (500’ ceiling<1000’; 1 vis<3 st mi) LIFR (<500’ and/or <1 st mi)

Aviation-Specific SREF Guidance n Cloud Amount n n n n Total mean Max mean Min mean Clear prob Scattered prob Broken prob Overcast prob

Aviation-Specific SREF Guidance n 10 m wind n n n Speed & direction mean > 10, 20, 30 kt prob Low-level wind shear (lowest 2000’ agl) n n Sfc – 2000’ mean Severe prob

Aviation-Specific SREF Guidance n Convective Cloud n n RUC Convective Probability Jet Stream n n Mean and spread Severe prob 4500’; 18, 000’; 34, 000’ Icing Probability n FL 000, 030, 060, 090, 120, 150, 180, 240

Aviation-Specific SREF Guidance n Turbulence probability n n n Light-moderate, severe FL 180 - 420 Tropopause height/temp Freezing level height Precipitation type Fog occurrence

Aviation SREF Dataflow n NAWIPS: n n Individual ensemble members only Would like Aviation SREF fields added to mean, prob, and spread GEMPAK files for NAWIPS

Aviation SREF Feedback n n n n Reduce/access/calibrate uncertainty Reduce/represent model error Provide distribution characteristics, etc. Algorithm enhancements, changes Hourly output F 00 -F 24 Add aviation-specific guidance to global ensemble Add mountain obscuration guidance

Aviation SREF Feedback n Application to AWC production & products n FAA requires deterministic aviation forecast products – except for probabilistic collaborative convective forecast product (CCFP)

Aviation SREF Verification/Validation n Verification/Validation is difficult n n NCEP FVS works for regular weather not for aviation weather n n n PIREPS difficult to use for turb, icing low level wind shear has been verified in FVS adapt FVS to aviation Collaborate with RTVS for aviation verification/validation

Summary n n Robust aviation-specific SREF guidance SREF used primarily for Cb forecasts n n n FAA requires deterministic forecasts Add aviation SREF fields to mean, spread, prob files in GEMPAK Need to calibrate aviation SREF fields, represent model error Excellent collaboration between AWC and EMC, SPC, and RUC Verification/validation issue: n n Difficult using PIREPs Collaboration between FVS and RTVS for verification/validation