2004 Developments in Aviation Forecast Guidance from the RUC Stan Benjamin Steve Weygandt NOAA / Forecast Systems Lab NY Courtesy: ADDS/AWC/NOAA FPAW Forum – October 2004 – Las Vegas

2 Convection h forecast Ceiling/visibility Turbulence Terminal / surface 3-d RUC weather data updated hourly 20km x 50 vertical levels x 14 variables Better weather products require improved high- frequency high-resolution models with high-refresh data to feed them Icing Winds

3 RUC changes  Impact on convection, ceiling/vis forecasts for aviation km RUC implementations completed – April – RUC model -vertical advection of moisture  better precip and clouds. More detailed land use/coastline. September – RUC analysis – use boundary-layer depth in assimilation of surface/METAR obs  better temp/dewpoint/CAPE/convection forecasts km RUC implementation planned Real-time testing since spring (see

4 3h CAPE forecast valid 0000 UTC 21 April 2004 Two revisions: 1)Better use of METAR obs using boundary-layer depth (Sept04) 2)Assimilation of GPS precipitable water observations (2005) Operational RUCRevised RUC Severe weather reports

5 13km RUC Improvements expected from 13km RUC - Improved near-surface forecasts - Improved precipitation forecasts - Better cloud/icing depiction - Improved frontal/turbulence forecasts New obs assimilated in 13km RUC - METAR cloud/vis data - GPS precipitable water (~300/hr) - Mesonet surface (temp/wind – 5000/hr) MHz profilers 20km RUC

6 Assimilation of METAR cloud, visibility, current weather observations into RUC Goal: Modify hydrometeor, RH analysis fields to 1) force near match to current ceiling/vis obs when passed through ceiling/vis translation algorithms 2) improve short-range predictions IFRLIFR VFR CLR MVFR To be part of oper 13km RUC

7 Cloud ceiling (m) RUC – with and without METAR cloud assimilation 18z Obs 17 Nov 2003 Diagnosed ceiling from RUC hydrometeors Corresponding Ceiling height - meters IFRLIFR VFR CLR MVFR METAR Flight Rules Oper RUC - w/o METAR cloud assim With METAR cloud assim

8 17z 27 Jan 04 analysis – After assimilation of METAR cloud/ceiling obs Cloud water mixing ratio (q c ),  Background – 1h fcst 17z – 27 Jan 04 MO KY VA

9 NCAR-RAP CV exp product – Flight Rules Oper RUC 13km RUC w/ c/v assim Observed – 1315z 7 Oct 04 GOES visible image 3h fcst Valid 14z 7 Oct 04

10 RUC20 RUC13 6h precipitation forecast Valid 18z Thurs 30 Sept 2004 RUC20 (oper) vs. RUC13

11 RUC CONVECTIVE PROBABILITY FORECAST (RCPF) Ensemble-based thunderstorm likelihood product 2, 4, and 6-h forecasts every two hours In-house testing 2003 and 2004 AWC evaluation planned for – use improved 13km RUC EVENTUAL GOAL Seamless 0-6 h convective guidance product (E- NCWF) Guidance to forecasters, traffic flow managers, automated decision support systems

12 Verification for 26 day period (6-31 Aug 2004) RCPFv2004 fcst is a 1-h older than RCPFv2003 RCPFv2004 has similar CSI, much improved bias RCPFv2003 vs. RCPFv2004 Forecast length Forecast Valid Time GMT EDT 6h Forecast RUC CONVECTIVE PROBABILITY FORECAST (RCPF)

13 25 – 49% 50 – 74% 75 – 100% Forecasts 09z + 6h Verification 15z NCWD 10 July 2004 RCPF v2004 POD =.49 CSI =.25 Bias =1.44 RCPF v2003 POD =.46 CSI =.18 Bias =2.00 Sample comparison RCPFv2003 and RCPFv2004 products GOALS in 2004 Reduce large bias Improve spatial coherency, temporal consistency

14 15z convection At fcst Time... RCPF v z + 6h Forecast 21z verif Sample RCPFv2004 product 25 – 49% 50 – 74% 75 – 100% Verification 21z NCWD 23 July 2004 Strength of RCPF - convective initiation RUC CONVECTIVE PROBABILITY FORECAST (RCPF)

15 Backbone of improved aviation forecast products for winds, icing, turbulence, convection, TAFs = weather model forecasts updated at high frequency with latest observations Keys to improvement of RUC model aviation forecasts Higher spatial resolution – better capture fine-scale weather hazards (13km resolution) Use new observations to initialize model – force more realism in model initial conditions (METAR ceil/vis obs, GPS moisture, mesonet) Improved realism of physical processes in model – clouds, turbulence, land-surface (revised physics) Collaboration between FSL, NWS, FAA, NCAR, MIT/LL, NASA, customers