Proposed RUC Change - September 2004 Stan Benjamin – NOAA/FSL Geoff Manikin – NOAA/NCEP/EMC Modifications to RUC analysis Improved surface / CAPE analyses and forecasts

2 History 1) RUC change package implemented on 14 April 2004 Included model, land-use, and analysis changes. Analysis change was mainly to use boundary-layer depth to better assimilate surface observations, goal: improve CAPE and boundary-layer analysis. 2)26 April 2004 – analysis change recalled (other changes retained). Problem – Noise in moisture fields, made worse by PBL-based assimilation. Recall advised by EMC and FSL. 3)May-June - FSL/EMC investigation / redesign. 4)Late June – Sept. EMC/NCO parallel testing of RUC with redesigned moisture analysis, including PBL-based assimilation.

3 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 surface based on estimated boundary-layer depth Original slides from April 2004

4 PBL-based METAR assimilation Problem: Representativeness of sfc data in PBL not used Design: Use METAR data through PBL depth from 1h fcst Create extra pseudo-residuals (obs-bkg) in PBL RUC oper analysis 18z 3 Apr 02 IAD Original slides from April 2004

5 Summary of proposed RUC analysis changes – September 2004 Use of boundary-layer depth in METAR assimilation - redesigned version Constrained moisture analysis increments Constrained moisture and temperature near-surface observation residuals

6 CAPE z 20 April 2004 RUC analysis Operational RUC Rerun of RUC (from 00z onward) with modified RUC analysis Problem areas Problem areas gone. Improved CAPE in IL/IA area (tornado outbreak)

7 PBL-based METAR assimilation Use METAR data through PBL depth from 1h fcst RUC oper analysis 18z 3 Apr 02 IAD x x x x Effect of PBL-based METAR assimilation

8 Effect of PBL-based assimilation RUC 6h CAPE fcsts Valid 2100z 10 Nov 2002 Oper RUC (OI analysis) RUC w/ 3DVAR + PBL obs Problem with all models in this case: Insufficient CAPE

9 RUC 6h fcsts -CAPE Valid 2100z 10 Nov 03 Oper - OI FSL rerun - 3DVAR FSL rerun -3DVAR + PBL obs

10 Parallel testing for RUC analysis change Real-time (warm season) 19 August – current time Retrospective (cold season) 1-20 February 2004

11 Cold-season testing – 1-20 Feb Upper-air wind RUC oper – solid RUCX - dashed 00h 03h 12h

12 Cold-season testing – 1-20 Feb Upper-air temp RUC oper – solid RUCX - dashed 00h 03h 12h

13 Warm-season testing – 19 Aug-20 Sep 04 - Upper-air wind RUC oper – solid RUCX - dashed 00h 03h 12h

14 Warm-season testing – 19 Aug-20 Sep 04 - Upper-air temp RUC oper – solid RUCX - dashed 00h 03h 12h

15 Warm-season testing – 19 Aug-20 Sep 04 – 2-m temp 00h 03h RUC oper – pink RUCX - blue Valid at 00z 3h12h Valid at 12z

16 Cold-season testing – 1-20 Feb 04 – 2-m temp RUC oper – pink RUCX - blue Valid at 00z 3h12h Valid at 12z

17 Case – 00z 21 July 2004 RUC2 – oper RUC20 RUCX – para - revised moisture anx incl. PBL-based assimilation Rome, OR Winnemucca, NV para oper

18 RUC2 – oper RUC20 RUCX – revised moisture anx incl. PBL-based assimilation Case – 12z 1 July 2004

19 RUC2 – oper RUC20 RUCX – parallel - revised moisture anx incl. PBL-based assimilation Case – 00z 13 July m temp

20 RUC2 – oper RUC20 RUCX – parallel -- revised moisture anx incl. PBL-based assimilation Case – 00z 13 July m dewpoint

21 Summary of proposed RUC analysis changes – September 2004 Use of boundary-layer depth in METAR assimilation - redesigned version - Constrained moisture analysis increments - Constrained moisture and temperature near-surface observation residuals Upper-air verification – slightly better than oper Surface verification – similar to oper Case studies – better CAPE, sfc temp/dewpoint analyses Interim fix for RUC moisture analysis for now. Planned change of moisture variable from ln-q to RH with 13km RUC package.