1

NMM, ARW in NCEP Operations• Pre-WRF NMM at NCEP• May 2000: nonhydrostatic option

released in upgrade to NCEP’s workstation Eta

• May 2001: NMM model equations, solution techniques & test results published in Janjic, Gerrity, and Nickovic, 2001, Mon. Wea. Rev. also Janjic, 2003, Meteor. & Atmos. Phys.

• February 2002: HiResWindow runs upgraded to use 8 km NMM replaces 10 km Eta (hydrostatic)

• February 2002: On-Call Emergency Response (OCER) capability begins using 4 km NMM to support HYSPLIT

• May 2003: Fire Weather / IMET Support runs implemented using 8 km NMM

• WRF-ARW at NCEP • September 2004: HiResWindow first

WRF implementation of 10 km WRF-ARW v1.3

• June 2005: HiResWindow upgraded to use 5.8 km WRF-ARW with explicit convection

• December 2005: Short Range Ensemble Forecasting system adds 3 members using 45 km WRF-ARW v2.0

• September 2007: HiResWindow expanded domain and upgraded to 5.1 km WRF-ARW v2.2.1

• October 2009: SREF WRF-ARW upgraded to v2.2.1, add 2 members and increase resolution to 35 km

2

WRF-NMM in NCEP Operations• April 2004 thru present:

NSSL/SPC Spring Program, daily developmental run of 4.5 km WRF-NMM with explicit convection

• September 2004: HiResWindow first WRF implementation of 8 km WRF-NMM v1.3 replaces pre-WRF NMM

• June 2005: HiResWindow upgraded to use 5.1 km WRF-NMM with explicit convection

• December 2005: Short Range Ensemble Forecasting system adds 3 members using 40 km WRF-NMM v2.0

• June 2006: NAM runs use 12 km WRF-NMM v2.1 & WRF-GSI replacing Eta & Eta-3DVar

• September 2007: HiResWindow expanded domain and upgraded to 4 km WRF-NMM v2.2.1

• December 2008: final major NAM/NMM upgrade

Runtime & optimal node apportionment for NMMB nesting with a Fire Wx nest over CONUS (30 nodes): 12 hr fcst in 1619 s [Matt Pyle]

3 km Puerto Rico nest 1.5/30 or 5%

1.33 km CONUS FireWx nest 5/30 or 17%

4 km CONUS nest 17/30 or 57%

3

3 km Hawaii nest 1.5/30 or 5%

12 km parent 3/30 or 10%

6 km Alaska nest 2/30 or 7%

WRF-NMM takes 3.6 times longer to run comparable nesting with Fire Wx nest over CONUS (30 nodes): 12 hr fcst in 5857 s [Matt Pyle]

4 km* Puerto Rico nest 30/30 or 100%

1.33 km CONUS FireWx nest 30/30 or 100%

4 km CONUS nest 30/30 or 100%

4

4 km* Hawaii nest 30/30 or 100%

12 km parent 30/30 or 100%

4 km* Alaska nest 30/30 or 100%

5

More Stats Showing Improved Computational Speed & Efficiency

• Runtime for NAM with 5 nests on 72 nodes:

Current opnl code: > 4 hours

New code: 70 minutes

• New NAM is doing 11 times more work than the current NAM, but uses only 7.7 times more compute resources!

• IBM estimates the NMMB will easily scale to at least 24,000 processors (if we could ever get them)

Why Does NMMB Run So Much Faster?NMMB NMM

Runtimes 1619 s 5857 s 3.6 x faster

Contribution to speed up

New Model Dynamics

NMMB NMM ~2%

Infrastructure NEMS WRF ~2%

Nesting

• NMMB specific• Outside of the NEMS infrastructure• Processor apportionment• 1-way nests solved simultaneously

• ~Core independent* • Part of the WRF infrastructure• No processor apportionment• 1-way nests solved sequentially

~96%

Horizontal resolution step-

down ratio

Any integer ratio, e.g. 2:1, 3:1, 4:1, …

Only 3:1*0% - this relates to flexibility, not

speed 6

Hypothetical NMMB Simultaneous Run Global [with Igor & Julia] and NAM [with CONUS nest]

27 km Global NMMB27 km Global NMMB

12 km NAM NMMB

12 km NAM NMMB

4 km NAM-nest NMMB9 km Igor NMMB

9 km Julia NMMB

Movable Storm Scale• SPC’s 2022 Requirement

– Inside every HRRRE member– Movable domain update SSEF: – 1 km movable regional domain – 20-30 member storm scale ensemble – advanced state-of-the-science DA – run every 1 hr with forecasts to 18-24 hr– focused on “severe weather of the day” areas

• In 2014, NAM upgrade could include– Movable FireWx nest tracking tropical storm– Movable FireWx nest with prescribed motion 8

Superstorm Sandy was ‘contained’ in fixed domainNAM 1.33 km nest from 18z 10/29/12

SLP, 1-h Accum Precip (in), 10-m wind (kt)

9

Superstorm Sandy was ‘contained’ in fixed domain NAM 1.33 km nest from 18z 10/29/121-h Maximum Wind Speed Gust (kt)

10

Hurricane Irene was not ‘contained’ in fixed domainNAM 1.33 km nest from 18z 10/29/12

SLP, 1-h Accum Precip (in), 10-m wind (kt)

1.33 km Moving nest

12

Courtesy Brad Ferrier,Eric Aligo & Dusan Jovic

1.33 km Moving nest

13

Courtesy Brad Ferrier,Eric Aligo & Dusan Jovic