2004 Developments in Aviation Forecast Guidance from the RUC
Stan BenjaminSteve Weygandt NOAA / Forecast Systems Lab
http://ruc.fsl.noaa.gov
NY
Courtesy: ADDS/AWC/NOAA
FPAW Forum – October 2004 – Las Vegas
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Convection - 2-12h forecast
Ceiling/visibility
Turbulence
Terminal / surface
3-d RUC weather dataupdated hourly
20km x 50 vertical levelsx 14 variables
Better weather products require improved high-frequencyhigh-resolution models with high-refresh data to feed them
Icing
Winds
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RUC changes Impact on convection, ceiling/vis forecasts for aviation
2004 - 20km 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
2005- 13km RUC implementation planned • Real-time testing since spring (see
http://ruc.fsl.noaa.gov)
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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 RUC Revised RUC
Severe weather reports
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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)- 915 MHz profilers
20km RUC
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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 - 2005
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Cloud ceiling (m)RUC – with and without METAR cloud assimilation
18z Obs17 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
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17z 27 Jan 04 analysis –After assimilation ofMETAR cloud/ceiling obs
Cloud water mixing ratio (qc),
Background – 1h fcst
17z – 27 Jan 04
MO KY VA MO KY VA
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NCAR-RAP CV exp product – Flight Rules
Oper RUC13km RUCw/ c/v assim
Observed –1315z7 Oct 04
GOES visible image
3h fcstValid 14z7 Oct 04
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RUC20
RUC13
6h precipitation forecastValid 18z Thurs 30 Sept 2004RUC20 (oper) vs. RUC13
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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 2005• 2005 – 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
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• 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
ForecastValid Time
GMT
EDT
6h Forecast
RUC CONVECTIVE PROBABILITY FORECAST (RCPF)
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25 – 49%50 – 74%75 – 100%
Forecasts
09z + 6h
Verification
15z NCWD
10 July 2004
RCPFv2004
POD = .49CSI = .25Bias =1.44
RCPFv2003
POD = .46CSI = .18Bias =2.00
Sample comparison RCPFv2003 and RCPFv2004 products
GOALS in 2004
• Reduce large bias
• Improve spatial coherency, temporal consistency
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15z convectionAt fcst
Time...
RCPFv2004
15z + 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)
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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
