the 13km ruc - nearing implementation at ncep changes, testing, plan aviation weather center –...
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The 13km RUC - Nearing Implementation at
NCEPChanges, testing, plan
Aviation Weather Center – Monday 16 May 2005
Stan BenjaminJohn BrownKevin BrundageDezso DevenyiGeorg GrellBill MoningerSteven Peckham
Barry SchwartzTanya SmirnovaTracy Lorraine SmithSteve Weygandt
Geoff Manikin – NCEP/EMC
RUC web site - http://ruc.fsl.noaa.gov
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2005- Implementation of 13km RUC in operations at NCEP
• Assimilation of new observations - GPS-precipitable water improved moisture forecasts
- METAR cloud/vis/current weather improved ceiling and vis fcsts
- Mesonet - 915 MHz boundary-layer profilers915 MHz boundary-layer profilers, RASS
temperatures- Soil moisture/temp nudging
2005Model changes – New versions of - mixed-phase cloud microphysics (NCAR-FSL) - Grell-Devenyi convective parameterization
- Revised radiation – cloud effects- Corrected treatment of frost formation
improved icing and convection forecasts, cloud/sfc temp, vis forecasts
• Improved post-processing – visibility, precip type, 20km/40km look-alike
• Hourly forecasts to be extended to 9h from 3h duration
(at 01z, 02z, 04z, 05z, …)
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What is different qualitatively in precip/surface behavior with the RUC13?
- Definitely a ‘wetter’ model than the previous RUCs
- Surface dewpoint, moisture aloft- CAPE- Precipitation
- But ‘drier’ over warm oceans
AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 1155 AM MDT SUN MAY 8 2005
.UPDATE... A SHORTWAVE TROF WAS EVIDENT THIS MORNING AT BOTH 700 AND 500 MB OVER SOUTHEAST WYOMING...SPREADING TOWARD THE TRI STATE AREA IN NORTHWESTERLY FLOW ALOFT. THE ETA/NAM WAS HANDLING THIS FEATURE WELL. THE RUC IS A BIT TOO DRY.
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2005 - 13km RUC implementation plan
February-May 2005- Real-time parallel testing – EMC- Intercomparison RUC13 vs. RUC20 by EMC, FSL
- daily inspection w/ graphics, statistics (raob, surface)- Transfer afterward to NCEP/NCO
May-June 2005- Real-time parallel testing – NCO- 4-week field test evaluation – NWS regions, AWC, SPC…
*** STARTING NEXT WEEK- Retrospective testing (at NCEP) for cold season- Report on testing to EMC, NCEP directors
~ June-July 2005- Operational implementation
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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
20km RUC
Terrain elevation - 200 m interval
NCEP computer upgrade allows RUC13 to run in same time as current RUC20
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RUC History – NCEP (NMC) implementations
1994 - First operational implementation of RUC- 60km resolution, 3-h cycle
1998 – 40km resolution, 1-h cycle, - cloud physics, land-sfc model
2002 – 20km resolution- addition of GOES cloud data in assimilation
2003 – Change to 3dVAR analysis from previous OI(April)
2005 – 13km resolution, new obs, new model physics(estimated ~June-July)
2007 – WRF-based Rapid Refresh to replace RUC
7More detailed coastline with 13km resolution
13km RUC 20km RUC
Soil moisture – 22z - 21 Feb 2005Dark blue = water
RUC 3DVAR development/testing
RUC Analysis Goals• Initial fields that yield very accurate
short-range forecasts (down to 1-h): - upper-level wind forecasts- aviation hazards (turbulence, icing,
ceiling/visibility)- surface sensible weather forecasts
• Hourly assimilation of all conventional observations, including surface observations
• Close analysis fit to all observations, especially METAR and rawinsonde
• 13-km 3DVAR running at FSL since summer 2004, NCEP testing in progress
5 aspects of RUC13 3DVAR analysis:
1. New observations assimilated
2. Cloud analysis (GOES, METAR ceiling/vis/curr-wx)
3. Use of surface obs throughout PBL (NCEP Fall 2004)
4. Revised control variable for moisture (pseudo-RH)
5. Soil moisture/temp nudging
Observations used in RUCData Type ~Number Freq.--------------------------------------------------Rawinsonde 80 /12hNOAA profilers 30 / 1hVAD winds 110-130 / 1h Aircraft (V,temp) 1400-4500 / 1hSurface/METAR 1500-1700 / 1hSurface/METAR 1500-1700 / 1hBuoy/ship 100-150 / 1hGOES precip water 1500-3000 / 1hGOES cloud winds 1000-2500 / 1hGOES cloud-top pres 10 km res / 1hSSM/I precip water 1000-4000 / 6h--------------------------------------------------GPS precip water ~300 / 1hMesonet ~5000 / 1hPBL – prof/RASS ~25 / 1hMETAR-cloud-vis-wx ~1500 / 1h--------------------------------------------------
NC
EP
R
UC
20
op
era
tion
al
RUC13
(at NCEP June 2005)
Cloudanalysisvariables
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Obs quality issues with RUC13
• Mesonet data• Winds of questionable quality – widespread siting, anemometer height problems• Will be later added from approved mesonet providers (e.g. OK Mesonet)• Assigned larger obs errors
• Boundary-layer profilers • Implementation deferred (decision – 6 May 05)• Quality appears to be poorer than NOAA-network profilers – better monitoring needed
• Rawinsonde moisture profiles• Intermittently shows incorrect saturation in lowest 200 mb• Detected in RUC13 processing using GPS PW neighbors
Use multiple data types to modify cloud,hydrometeor, and moisture fields:
-- GOES cloud-top pressure/temp(implemented in 2002 w/
RUC20)-- Surface METAR (clouds, weather, visibility)
(2005 w/ RUC13)
• Construct 3-d logical arrays (YES/NO/UNKNOWN)
for clouds and precipitation from all info
• Clear/build moisture, cloud, precipitation fields
• Safeguards for known problems (marine stratus,
convective clouds, snow, nocturnal inversion)
RUC Cloud Analysis
-Nearest station up to 100 km distance- Assigned in ASL, includes terrain intersection for low clouds
- Maps info to 3-d cloud, precip. Y/N/U arrays - Change cloud water, cloud ice, water vapor fields as follows: Build for BKN / OVC / Vertical Visibility - 40 mb thick layer (2+ model levels) - 150 mb thick for precip. + GOES clouds - Can build multiple broken layersClear - Up to cloud base (if needed) - to 12,000 feet for CLR report
Assimilation of METAR cloud/wx/visBetter analysis, prediction of ceiling and visibility
analysis – withMETAR cloud/visibility obs
Cloud water mixing ratio
Sample modificationof cloud water from METAR cloud/weather/visibility observations
Cloud water mixing ratio
400Pres(mb)
-500-
-600-
-700-
-800-
-900-
1000
1700 UTC 27 Jan 2004
Background(previous1h fcst)
RelativeHumidity
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IFRLIFR VFR CLR MVFR
Sample ceiling analysis impact
Ceiling from RUC hydrometeors
AnalysisWITH
cld/wx/vis obs
AnalysisNO
cld/wx/vis obs
Aviation Flight Rules
cloud ceiling height (meters)
1800 UTC 17 Nov 2003
Observations
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GPS precipitable water observations~200-300/h - All-weather obs
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Analysis fit to GPS precipitable water obs over CONUS
RUC20
RUC13RMS difference
Bias
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3h forecast fit to GPS precipitable water obs over CONUS
RUC20
RUC13
RMS difference
Bias
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RUC enhancements:
1. Use of METAR obs throughboundary-layer depth (Sept 04)
2. Assimilation of GPS precipitable
water observations (RUC13 - ~Jun05)
CAPE impact from two RUC enhancements
3h fcst WITHenhancements
3h fcstOPERATIONAL
0000 UTC 21 Apr 2004
Severe reports
NWS SPCNorman, OK
Tornadoes
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• September 2004 – Change to oper RUC20 analysis
– use boundary-layer depth in assimilation of surface/METAR obs better temp/dewpoint/CAPE/convection forecasts
Spring 2005 – Will be first convective season to see effect of PBL-based assimilation. Also will be evident in RUC13 results.
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Problems with model PBL structure in RUC analysis
Sounding structure is sometimes not realistic and does not account for boundary-layer depth
No accounting in current RUC analysis for vertical correlation of forecast error near surfacebased on estimated boundary-layer depth
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PBL-based METAR assimilationProblem: Representativeness of sfc data in PBL not usedDesign: Use METAR data through PBL depth from 1h fcst Create extra pseudo-residuals (obs-bkg) in PBL
RUC oper analysis18z 3 Apr 02IAD
Original slides from April 2004
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PBL-based METAR assimilation
Use METAR data through PBL depth from 1h fcstRUC oper analysis
18z 3 Apr 02IAD
x xxx
Effect of PBL-basedMETAR assimilation
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EMC/Geoff Manikin RUC20/13 comparison web pagehttp://www.emc.noaa.gov/mmb/ruc2/para
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EMC/Geoff Manikin RUC20/13 comparison web pagehttp://www.emc.noaa.gov/mmb/ruc2/para
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Revised moisture analysis design in RUC13 – pseudo-RH
Current RUC20• Separate analyses of in-situ moisture observations and precipitable water obs with intervening recalculation of observation innovations• Use of log (water vapor mixing ratio-qv) as analysis control variable for moisture.
• Some good characteristics (continuous in 3-d space, will not go negative) but not ‘responsive’ to increase RH (e.g., from 10% to 50%)• Related to summer 2004 RUC analysis fixes to avoid CAPE noise problems
Revised RUC13• Fully integrated moisture analysis with both in-situ and precipitable water obs treated together• Uses pseudo-RH (RH relative to background sat qv) as analysis control variable
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RUC13-exp
RUC20-ops
RUC13 matches moisture profiles much better than OperRUC20
• Use of pseudo-RH moisture control variable instead of Log (water vapor mixing ratio) used in RUC20.
TUS soundings – 12z 18 April 2005
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RUC13-exp
RUC20-ops
RUC13 forecast soundings at TUS also better than RUC20 - Reasons• Assimilation of GPS PW• Improved soil moisture in RUC13
• Better physics/assimilation, soil nudging
TUS soundings – 12z 18 April 2005
RUC 6h forecasts valid 12z
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36h afterrestoration of oper RUC20 soil moisture
Oper RUC20
Para RUC13
6h fcst valid 00z Analysis valid 00z
2m dewpoint- 00z 22 Apr 05 - excessivedryness in RUC20
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RUC13 analysis – includes nudging of soil moisture and temperature
Dependent on:• 2m T/Td 1h forecast errors• Only in daytime (zen angle > 0.3) with no clouds or precipitation (defined after METAR/GOES cloud assimilation)
Developed as part of NOAA New England High-Resolution Temperature (NEHRT) Program- FSL, ETL, NSSL, NCEP/EMC
Oper RUC20
Para RUC13
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Oper RUC20
Para RUC13
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Typical CAPE effect from improved soil moisture and moisture analysis in RUC13
12h forecastsValid Thur evening00z- 5 May 05
Oper RUC20
Para RUC13
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Typical CAPE effect from improved soil moisture and moisture analysis in RUC13
Para RUC13
Oper RUC20
More convective precip inRUC13 over land, less over ocean
CAPE
0-12h prec
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Typical CAPE effect from improved soil moisture and moisture analysis in RUC13
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MODEL PHYSICS CHANGES FOR RUC13
-Land-surface model: When ground temp < 0°C, vapor deposition on ground now based on ice saturation, not water * Diminishes unrealistic widespread nighttime fog formation, especially over snow cover
Evident in real-time comparisons between RUC13 and oper RUC20 for visibility forecasts, especially at night.
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Test of Ice Saturation for Surface Latent-heat Flux
13 Apr 2004 - 18h fcst valid 06z
Oper RUC20 Revised RUC20
Cloud-water mixing ratio at lowest model level
Reduction in fog, especially over snow.Much improved visibility forecasts, avoids high bias
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RUC13 Model Physics Changes (cont)
-Convection (Grell-Devenyi scheme) * Empirically estimated ensemble weights to improve quantitative precipitation forecasts
RUC20 - dCAPE/dt- Kain-Fritsch – CAPE relaxation- low-level vertical velocity- moisture convergence
RUC13 - adds Arak-Schu scheme for cloud work fn
- no KF over ocean, reweighted all closures• Addition of convection-inhibition ensemble members
• CAPE dp – 25, 75, 125 mb – fn ( TKE)• Does not produce significant outflows (slightly more in RUC13)• Still no shallow convection in RUC13 Grell-Dev scheme
• Still much less sounding modification than NAM/BMJ• Eliminated extreme surface drying showing up in certain situations
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RUC13 Model Physics Changes (cont)- Microphysics [NCAR and FSL]
Overall goal: To incorporate best understanding of “warm-rain” and mixed-phase processes important for cold-season aviation operations (inflight icing, pre-takeoff deicing requirements, low ceiling, visibility) into operational NWP models. Major changes for RUC13 • Dropsize distribution now transitions
between drizzle and rain • Replace Kessler with Barry-Reinhardt autoconversion (collision-coalescence cloud droplets to rain) Correct ice-particle accretion (ice snow more readily) Ice particle fall speed no longer set to 1 m/s
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RUC13 Model Physics Changes (cont)
* - Snow
- Diagnosis of snow-particle size distribution - Operational RUC20: - Depends on snow mixing ratio - RUC13: - Depends on temperature
- Graupel
- Growth/depletion via deposition/sublimation: Change size distribution from gamma to inverse exponential
- Results in less graupel
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EAST COAST BOMB 22-23 JAN 2005RUC13 9h Forecast for 0900 UTC 23 Jan
Sfc wind, temp, 3-h pcpnPrecipitation type
Snow
Rain
X-sec
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HYDROMETEOR CROSS SECTIONS
RUC13 RUC20 - OPER
CLOUD-WATER MIXING RATIO (qc)
Atlantic MA ME
RUC 9h Forecasts for 0900 UTC 23 Jan
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Hydrometeor Mixing Ratios (Cont)RAIN WATER (qr)
RUC13
Atlantic MA ME
Oper - RUC20
More rain in RUC13 – different rain processes
RUC 9h Forecasts for 0900 UTC 23 Jan
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Hydrometeor Mixing Ratios (Cont)CLOUD ICE (qi)
RUC13 Oper RUC20
Atlantic MA ME
Less ice in RUC13 – modified ice-particle accretion
RUC 9h Forecasts for 0900 UTC 23 Jan
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Hydrometeor Mixing Ratios (Cont)SNOW (qs)
RUC13 Oper RUC20
Atlantic MA ME
More snow in RUC13 – modified ice-particle accretion
RUC 9h Forecasts for 0900 UTC 23 Jan
45
Hydrometeor Mixing Ratios (Cont)GRAUPEL (qg)
RUC13 Oper RUC20
Atlantic MA ME
Less graupel in RUC13 More supercooled liquid water (important for icing/aviation)
RUC 9h Forecasts for 0900 UTC 23 Jan
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RUC13 Model Physics Changes (cont)
- Coupling between physics processes * Reduction of cloud attenuation coefficients for
shortwave and longwave transmission to match WRF/MM5
* Effects of microphysics changes (more ice fallout - results in less Cirrus, Cirrostratus) on radiation budget and surface temperature forecasts
* Detrainment of hydrometeors from convection to the grid scale – More latent heating due to freezing on explicit scale in convection
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2004/05 - 13km RUC testing
Fall 2003 - 13km RUC model real-time testing started- Initialized from 20km analysis, run 4x daily
May 2004 – Full 1-h cycle testing started
Evaluation - FSL verification – against raobs, sfc, precipitation obs - 13km RUC vs. backup RUC – raob
- NOAA New England High-Resolution Temp Project - ETL, NSSL evaluation - June-Sept 2004
- Experimental use in NWS Central and Eastern Region WFOs
- July 2004 – current - Available via LDM from FSL (contact Tracy Smith)- NCEP pre-implementation testing started – Jan 05
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RUC20
RUC13
6h precipitation forecastValid 18z Thurs 30 Sept 2004RUC20 (oper) vs. RUC13
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Obs radar - 0235z - 31 Mar 05
RUC13 9h fcst - valid 03z- 31Mar05
RUC20 9h fcst - valid 03z - 31 Mar 05
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Obs radar - 0115z - 12 May 05
RUC13 12h fcst - valid 03z- 12May05
RUC20 12h fcst - valid 03z- 12May05
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CAPE
Oper RUC20
Exp RUC13
Improved moisture analysis in RUC13 – pseudo-RH instead of ln-qv- use of GPS PW
Thursday 21 April 2005 – 12z
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Thursday 21 April 2005 – 12z
Oper RUC20
Exp RUC13
Improved moisture analysis in RUC13 – pseudo-RH, GPS PW
Radar summary – 1400z
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RUC20 vs. RUC13 precipitation forecast (12h) verificationWinter –Jan-Feb 05 (verified w/ NCEP 24h precip analysis)
RUC13-higher equitable threat score- bias closer to 1
Why?- Improved initial conditions- Improved precip physics- Higher horizontal resolution
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RUC20 vs. RUC13 precip forecast – 24h period ending 12z - 12 Feb 2005 (verified w/ NCEP 24h precip analysis)
RUC20
RUC13
obs
(inches)
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Ceiling analysis: comparison of Operational RUC (top) with the NCEP RUC13 (bottom)
Scale (AGL): x 1000 ft
Analyses at 1800 UTC on 9 May
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Observations: cigs <= 5000 ft only
Observations: cigs <= 500 ft onlyPoint observations at 1800 UTC 9 May, for different ceiling heights, to compare to previous figure. 4 areas of lower cigs are apparent. -New England: Better coverage of lower cigs by RUC13 looks good. -Northern Plains/Midwest: more coverage of lower cigs in RUC13, tho similar coverage for very lowest categories. Again, obs for aob 5000 ft cigs support RUC13. -West Coast: both have lower cigs in LA area. More coverage on RUC13 in intermountain west, not sure if this is overdone or not. -Northeast TX: RUC13 looks better here.
Observations: cigs <= 3000 ft only
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Ceiling 1h forecasts: comparison of Operational RUC (top) with the NCEP RUC13 (bottom)
Scale (AGL): x 1000 ft
Forecasts at 1900 UTC on 9 May
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Ceiling 3h forecasts: comparison of Operational RUC (top) with the NCEP RUC13 (bottom)
Scale (AGL): x 1000 ft
Forecasts at 2100 UTC on 9 May
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Focus on the Midwest and Northern Plains. Quite a few obs have cigs < 3000 ft, but only a few lower vis reports. It does appear that low clouds lurk JUST east of the eastern WI shoreline, like what was found in the RUC Operational run.
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Focus on eastern Texas. Cigs < 3000 ft are relatively widespread.
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Variable RUC20 RUC13
Temp –s.d. East domain 2.8 2.6
Temp – s.d. West domain 3.6 3.3
Dewpoint – s.d. East domain 2.9 2.7
Dewpoint – s.d. West domain 3.5 3.2
12-h surface forecasts verified vs. METAR obs25 Nov 2004 – 18 Jan 2005 - every 3 h (00z,03z,…21z)
20-km RUC (oper) vs. 13-km RUC
- METARs in RUC domain (East/West of 100° W)- RUC13 uses 13km mini topography field derived from 3.3km topo
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Rawinsonde verification - wind - RUC13 vs. RUC20
-RUC13 provides improvement in 150-300 mb winds
20km 13km
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Rawinsonde verification - RH - RUC13 vs. RUC20
-RUC13 provides much better RH forecasts- With RUC13, 3h RH forecasts are more accurate than 12h RH forecasts (unlike RUC20) GOES and GPS used (more) effectively, physics improved also.
20km 13km
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2005 - 13km RUC implementation plan
February-May 2005- Real-time parallel testing – EMC- Intercomparison RUC13 vs. RUC20 by EMC, FSL
- daily inspection w/ graphics, statistics (raob, surface)- Transfer afterward to NCEP/NCO
May-June 2005- Real-time parallel testing – NCO- 4-week field test evaluation – NWS regions, AWC, SPC…- Retrospective testing (at NCEP) for cold season- Report on testing to EMC and NCEP directors
~ June/July 2005- Operational implementation
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RUC13 output grids• ~Same products/fields as for RUC20 and RUC40
– Add sfc-based CAPE to best-300mb CAPE
• 20km and 40km look-alike grids – Native (Note: 50 levels instead of 40)
– 25-mb isobaric and 88 2-d grids – 25 2-d variables
• BUFR station time series output– nearly identical to Eta (Exception: 5 soil levels with RUC (out of
actual 6) compared to 4 with Eta/NAM model)– RUC13 – station files with all output time (as with RUC20)- RUC13 – improved land/water matching (important for coastal
stations)• Continue RUC web forum for questions (under RUC web site)
• Continue RUC hot backup – transition to 13km
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2005- Implementation of 13km RUC in operations at NCEP
• Assimilation of new observations - GPS-precipitable water improved moisture forecasts
- METAR cloud/vis/current weather improved ceiling and vis fcsts
- Mesonet, RASS temperatures2005Soil moisture/temp nudging2006Improved moisture analysis – pseudo-RH instead of
log q2007Model changes – New versions of - mixed-phase cloud microphysics (NCAR-FSL) - Grell-Devenyi convective parameterization
- Revised radiation – cloud effects- Corrected treatment of frost formation
improved icing and convection forecasts, cloud/sfc temp, vis forecasts
• Improved post-processing – visibility, precip type, 20km/40km look-alike
• Hourly forecasts to be extended to 9h from 3h duration
(at 01z, 02z, 04z, 05z, …)(12h forecasts to be continued at 00z, 03, 06… init
times)