2.4 Experimental Upgraded LAMP Convection and Total lightning Probability and "Potential" Guidance for CONUS

Monday, 23 January 2017: 2:15 PM
Conference Center: Skagit 2 (Washington State Convention Center )
Jerome P. Charba, Meteorological Development Laboratory, Silver Spring, MD; and F. G. Samplatsky, P. E. Shafer, J. E. Ghirardelli, and A. J. Kochenash
Manuscript (1000.5 kB)

Automated operational 1-25 h LAMP (Localized Aviation MOS Program) convection and cloud-to-ground lightning (CG) probability and potential guidance forecasts developed by the Meteorological Development Laboratory (MDL) of the National Weather Service have been issued hourly for the CONUS since March 2014.  The convection product is targeted for tactical and strategical aviation forecast applications, whereas the CG guidance is targeted for wildfire management and public safety applications.  The temporal resolution of these gridded products is two hours and the grid resolution is 20 km, each of which is coarser than preferred by some users.  MDL is addressing the need for higher resolution by reducing the valid period to one hour and the grid mesh to 10 km.  To support the higher resolution, cutting-edge fine scale datasets are utilized, including Multi-Radar Multi-Sensor (MRMS) reflectivity products developed and recently implemented by NOAA National Severe Storms Laboratory, total lightning [TL -- a composite of CG and in-cloud (IC)] flashes reported by Earth Networks, Inc., and output from the High Resolution Rapid Refresh (HRRR) model developed and recently implemented by NOAA Earth System Research Laboratory.

The experimental, upgraded LAMP convection predictand is defined as occurrence/non-occurrence of ≥ 40 dBZ radar reflectivity and/or ≥ 1 TL flashes in 20-km gridboxes spaced 10 km apart over a 1-h period.  The corresponding lightning predictand is specified as the TL component of the convection definition.  Since the convection specification is dominated by the radar component, redundancy between the two predictands is small.  Also, replacement of CG flashes embodying the currently operational convection or lightning predictand with (more frequent) TL flashes in the corresponding upgraded predictand provides a more complete specification of convection or lightning events and accommodates higher temporal resolution.

The predictor base for the multiple-regression-based convection or TL probabilities consists of a blend of the most recent and advected radar and lightning parameters, HRRR products, and the National Centers for Environmental Prediction Global Forecast System (GFS) - and North American Mesoscale Model (NAM) -based model output statistics (MOS) convection or TL probabilities.  The observational predictors yield fine detail and high skill in the first few LAMP hourly valid periods, HRRR predictors skillfully extend detail out to 17 hours, and MOS probabilities specify large scale forecast patterns (with modest skill) for all LAMP forecast projections.

The upgraded LAMP convection and TL guidance products are presently being issued experimentally in real time for user evaluation and feedback (early convection feedback has been quite favorable).  The conference presentation will describe how the probability and potential products are formulated, their performance, and the anticipated implementation schedule.

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