Public Information Statement
Issued by NWS National HQ
Issued by NWS National HQ
170 NOUS41 KWBC 031550 PNSWSH Service Change Notification 24-36 National Weather Service Headquarters Silver Spring MD 1150 AM EDT Wed Apr 3 2024 To: Subscribers -NOAA Weather Wire Service -Emergency Managers Weather Information Network -NOAAPORT Other NWS Partners, Users and Employees From: Patrick T. Marsh Chief, Science and Support NWS/Storm Prediction Center Subject: Upgrade to SPC Post Processing for NCEP Models, Effective May 7, 2024 On or about May 7, 2024, beginning with the 1200 Universal Coordinated Time (UTC) model run, the National Centers for Environmental Prediction (NCEP) will upgrade SPC_POST, SPCs postprocessing package for the NCEP model suite, to v2.0. In the event that the implementation date is declared a Critical Weather Day (CWD), an Enhanced Caution Event (ECE), or other significant weather is occurring or is anticipated to occur, implementation of this change will take place at 1200 UTC on the next weekday not declared a CWD and when no significant weather is occurring. In preparation for the retirement of the Short-Range Ensemble Forecast (SREF) system, HREF/GEFS calibrated severe guidance is generated using storm information from the High-Resolution Ensemble Forecast (HREF) system and environment information from the Global Ensemble Forecast System (GEFS). HREF/GEFS provides hazard-specific calibrated severe guidance for 4-hour periods through day 2 and for full periods for day 1 (both 00Z and 12Z runs) and day 2 (12Z runs only). The file name convention for these files is severe/spc_post.tCCz.href_cal_gefs_HAZ_ENV.ACChr.fFFF.grib2 where CC is the HREF cycle (00 or 12), HAZ is the hazard (either tor, wind, or hail), ENV is the initialization hour for the GEFS run used for the environment data (00, 06, 12, or 18), ACC is the accumulation length (either 4 or 24) and FFF is the 3-digit forecast hour. This version of SPC_POST continues the HREF Calibrated Thunder (HREFCT) and HREF/SREF products from the previous version of SPC_POST and adds several capabilities. The only change to existing output of HREFCT is to the file names to follow established conventions. The file names on the NOAA Operational Model Archive and Distribution Service (NOMADS) and FTPPRD (see below for the URLs) change as follows: thunder/hrefct.tCCz.thunder_1hr.fFFF.grib2 => thunder/spc_post.tCCz.hrefct_1hr.fFFF.grib2 thunder/hrefct.tCCz.thunder_4hr.fFFF.grib2 => thunder/spc_post.tCCz.hrefct_4hr.fFFF.grib2 thunder/hrefct.tCCz.thunder_full.fFFF.grib2 => thunder/spc_post.tCCz.hrefct_full.fFFF.grib2 Finally, this upgrade also adds GEFS-MLP, machine-learning based severe weather guidance through day 8 based on the GEFS. The algorithm is a random-forest method originally developed by researchers at Colorado State University. GEFS-MLP provides probabilistic individual hazard guidance through day 3 and probabilistic total severe guidance on days 3-8. The file naming convention is as follows: gefs_mlp/spc_post.tCCz.gefsmlp_HAZ_SIG.fFFF.grib2 where CC is the cycle (00 or 12), HAZ is the hazard (either tor, wind, hail, or severe), SIG is either std for any severe or sig for significant severe, and FFF is the 3-digit forecast hour. A consistent parallel feed of data will be available on the NCEP parallel NOMADS site beginning at least 30 days prior to implementation at the following location: https://nomads.ncep.noaa.gov/pub/data/nccf/com/spc_post/para/ https://www.ftp.ncep.noaa.gov/data/nccf/com/spc_post/para/ tp://ftp.ncep.noaa.gov/pub/data/nccf/com/spc_post/para/ New and existing data files for SPC_POST will remain at their current location on the NOMADS/FTPPRD web services at: https://nomads.ncep.noaa.gov/pub/data/nccf/com/spc_post/prod/ https://www.ftp.ncep.noaa.gov/data/nccf/com/spc_post/prod/ ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/spc_post/prod/ For questions regarding this change, please contact: Tim Supinie NWS/Storm Prediction Center, Norman, OK tim.supinie@noaa.gov For questions regarding the data flow, please contact: Tony Salemi NCEP/NCO Implementation and Data Services Branch College Park, MD 301-683-0567 Email: ncep.pmb.dataflow@noaa.gov National Service Change Notices are online at: http://www.weather.gov/notification