NOUS41 KWBC 061910



Technical Implementation Notice 13-23

National Weather Service Headquarters Washington DC

310 PM EDT Tue Aug 6 2013


To:       Subscribers:

          -Family of Services

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners, Users and Employees


From:     Timothy McClung

          Science Plans Branch Chief

          Office of Science and Technology


Subject:  Temporary Change to Preemption of HIRESW:

          Effective August 13, 2013


Effective on or about Tuesday, August 13, 2013, beginning with

the 1200 Coordinated Universal Time (UTC) run, the National

Centers for Environmental Prediction (NCEP) will modify the

preemption of the High-Resolution Window Forecast System



Due to resource limitations, NWS has had to cancel select HIRESW

runs during hurricane season depending on the number of hurricane

models running during that cycle. Currently, the HIRESW runs are

preempted when there are 3 or more tropical storms being run.


Because of the increased size and power of the new WCOSS

supercomputers, beginning August 13, the HIRESW runs will not be

preempted until 4 or more tropical storms are being run. This

rule will apply for the remainder of the 2013 hurricane season

only. Once the HIRESW suite is upgraded late this year or early

next year, the preemption limit likely will return to a smaller

number of storms. With a subsequent upgrade to either the

Hurricane Weather and Research Forecast (HWRF) or the HIRESW, the

preemption could begin with just 1 storm. A new Technical

Implementation Notice would alert users to such a change.


Long term, the HIRESW functionality will be covered by the High

Resolution Rapid Refresh ENSEMBLE (HRRRE), which will provide 

18-24 hour guidance updated hourly, and by the Short Range

Ensemble Forecast (SREF), which will provide longer range

ensemble guidance by extending the HRRRE members to 48-60 hours,

4 times per day.  This configuration (roughly 2018) will

alleviate the need for any preemption.


For questions regarding these model changes, please contact:


  Geoff Dimego

  NCEP/EMC, Mesoscale Modeling Branch

  College Park, Maryland, 20740



NWS National Technical Implementation Notices are online at: