Warn on Forecast Briefing September 2014

Warn on Forecast Brief for NCEP planning

NSSL and GSD

September 2014

Warn on Forecast Briefing September 2014

Warn on Forecast Vision (~2020+)• Short-term NWP forecasts at 0.5-1.0 km resolution

• Using improved models for convective-scale NWP

• Incorporation of high-resolution satellite and radar data

• Sub-hourly update cycle with 2-3 hour forecasts

• Providing uncertainty estimates via an ensemble system

• New paradigm for severe weather warnings

• Blend WoF output with observed/historical radar data• Blending using the Multi-Year Reanalysis Of Remotely-Sensed Storms (MYRORSS)

• Similar approach is used by NHC

• Extending lead times (1 hour for tornadoes, 2-3 hours wind, QPF, hail)

• Probabilistic warnings visualized using)

• Probabilistic Hazard Information tools (PHI)

• Forecasting A Continuum of Threats tools (FACETS)

• Leveraging societal knowledge and its technology

• Improving warning effectiveness via social science research

• Communicating threat information via new media

Warn on Forecast Briefing September 2014

• Assimilation• relative value of hybrid versus pure ensemble approaches as well as multi-resolution approaches

• ensemble ICs and mechanisms for maintaining optimal forecast spread (uncertainty)

• dealing with model biases

• use of dual-polarization data

• Observations• data quality control for dBZ, Vr, and dual-polarization variables

• optimal combinations of surface, radar and satellite

• appropriate superobbing for dense observational data

• Models

• Reducing model errors in PBL, radiation, and land surface

• appropriate microphysics relative to observations (e.g., single-pol versus dual-pol radar data)

• Verification• quantitative ensemble object based verification

• best methods to quantify model skill for these types of high-impact & rare events?

• value of high-resolution WoF system for non-severe convective weather

• Predictability

• what is the practical predictability for different environments and weather threats?

• how long does high-resolution satellite/radar data assimilation positively impact forecasts?

• hail and lightning?

Current Research Issues

Warn on Forecast Briefing September 2014

• Operational Implementation?• Background: Hourly-updated ~60 member 3 km convective-permitting model

• Warn on Forecast system:

• 0.5-1 km resolution with ~60 members

• Regional grid (1500-2000 km size grid, possibly moving)

• 5-15 min cycling with 1-3 hour forecasts generated 4-6x per hour

• 15 min latency (e.g., forecast is available T+15 minutes).

• Inputs: sub-hourly radar, satellite (GOES-R?), mesonet obs.

• Outputs: rotation tracks and intensities, QPF, severe wind probabilities, hail, etc.

• Operational Use?• WoF system is an ON-DEMAND service, much like HWRF is today.

• NOAA Storm Prediction Center would control placement and activation of WoF system (that would be run at NCEP)

• Output would be made available to SPC and WFOs through products

• WFOs might “blend” products locally for their needs with other observations(?)

• FACETS and PHI tools would consolidate model output and observations for forecasters into probabilistic threat information

Operational Warn on Forecast?

Warn on Forecast Briefing September 2014

• Research and development of a Warn on Forecast system is on track for end-of-decade specification for NCEP

• NSSL and GSD are working closely together to develop the high-resolution and high-frequency NWP system to provide probabilistic hazardous weather information for watches and warnings in 2020s.

• Given current state of NWP science for convective scale:

• high-resolution & high-frequency will likely regional grid initially (~40K cores?)

• system runs on-demand at NCEP? (like HWRF does?)

• SPC: logical center to decide on location for WoF on high-impact days.

• SPC and WFO’s can collaborate as to configuration (similar to how the convective outlooks and watches are already done)

• unclear yet whether sub-hourly 0.5-1 km forecasts will be useful for non-severe convective weather situations.

Summary