1. New Developments in Aviation Forecast Guidance from the RUC
(Rapid Update Cycle)
Stan Benjamin
NOAA /
Forecast Systems Lab NY
Courtesy: ADDS/AWC/NOAA

2. 3-d RUC weather data updated hourly 301 x 225 x 50 vertical levels
x 14 vars  47,000,000 data pts
for each analysis or fcst time
Turbulence
Convection -
2-12h forecast
Ceiling/visibility
Icing
Terminal / surface
Better weather products require
improved high-frequency
high-resolution models
with high-refresh data to feed them

3. RUC vector (kts) forecast error – 1200 UTC 8 Feb 2001 – FL350 (250 mb)
12h init 12z
9h init 03z
Purpose of RUC – Improved
forecast guidance using
high-frequency updates
initialized with recent
observations
6h init 06z
3h init 09z
kts

4. RUC20 Wind forecast Accuracy Sept-Dec 20021 6 9 3 12
Analysis
~ ‘truth’
(kts)
Verification against rawinsonde data over RUC domain
RMS vector difference (forecast vs. obs)
RUC is able to use recent obs to improve forecast skill down to 1-h projection for winds

5. Verify RUC sfc fcsts against all U.S. sfc obs 10-m wind speed
0-h
1-h
3-h
6-h
9-h
12-h
Fcst
Length
10-m wind speed
Persist
SUM (Apr–Sep)
WIN (Oct–Dec)
0-h
1-h
3-h
6-h
9-h
2-m temperature
Persist
RUC improves surface wind, temp skill down
to 1-h fcst
Much better than 1-h, 3-h persistence forecasts
12-h
Fcst
Length

6. RUC Convective Forecast
20km convective
Precipitation (mm)
(1 mm = 0.04”)
Probability of 0.08”
within 60 km
A preliminary
RUC Convective Forecast
Product guidance tool
5h forecasts valid 19z 4 Aug 2003
50% prob of 0.08”
within 60 km

7. Calibrating the preliminary RUC convective forecast product
RUC-CFP Version 1 (preferred)
CCFP – 4h forecast valid 19z
Obs – 19z - NCWD
50% prob of 0.08”
within 60 km
POD=0.40
Bias = 1.1
CSI = 0.23
RUC-CFP Version 2
POD=0.32
Bias = 0.95
CSI = 0.20
25% prob of 0.04”
within 40 km
POD=0.68
Bias = 2.6
CSI = 0.23
Calibrating the preliminary
RUC convective forecast product
guidance
5h forecasts valid 19z 4 Aug 2003

8. Sample RTVS verification
CSI for RUC
Guidance and
CCFP
12z (13z) fcst
Valid 19z
August 2003
RUC
CCFP

9. Summary on RUC convective product
(RUC-CFP) guidance
Preliminary RUC-based convective probability product
– compares favorably w/ CCFP skill in cases examined
- work just started in 2003
- research with NCAR, MIT/LL
Needs RTVS evaluation (underway)
Quality expected to improve with use of
Multiple model runs valid at same time
Model-internal convective probability data
Assimilation of radar reflectivity data
Calibrating RUC-CFP requires interaction w/ ATM (and other) user communities

10. RUC – in testing – Assimilation of radar reflectivity
RUC first guess
Radar adjusted
1200 UTC 3 May 2002
RUC max Refl. (dBZ)
RUC – in testing – Assimilation of radar reflectivity
RUC 3-h fcst
no radar data
RUC 3-h fcst
with radar data
1500 UTC 3 May 2002
RUC 3-h precip. (in)

11. RUC Upgrades 20 km/50 level 1 hr version – implemented May 2002
40km RUC topography
20km RUC topography
RUC Upgrades
20 km/50 level 1 hr version – implemented May 2002
Replaced previous 40km / 40 level version
Main operational implementation in 2003
Improved analysis (3-d variational) technique to improve initial conditions for RUC model (27 May 2003)
Next -13km RUC topography
WRF model in RUC

12. Backbone of improved aviation forecast products for
winds, icing, turbulence, convection, TAFs
= weather model forecasts updated at
high frequency (1 h) with latest observations
Keys to improvement of model aviation forecasts
in RUC20 and future versions:
Higher spatial resolution
– better capture fine-scale weather hazards
Use new observations to initialize model
– force more realism in model initial conditions
Improved realism of physical processes in model
– clouds, turbulence, land-surface