Global to regional fire weather forecasts

J. Roads1, S. Chen2, Francis Fujioka3, H. Juang4, M. Kanamitsu5
Experimental Climate Prediction Center, UCSD, 0224 La Jolla, CA 92093-0224, USA.
Tel.: +1-619-534-2099, Fax: +1-619-534-8561,
E-mail: jroads@ucsd.edu
3Forest Service, Riverside, CA, USA
4,5NCEP, Camp Springs, MD, USA

A modelling system, developed at NCEP for making short-range global to regional weather forecasts, is being used to make global to regional, monthly fire weather forecasts. The system uses a regional spectral model (RSM), which is a high resolution regional spectral model nested within NCEPís MRF or GSM (global spectral model). The nesting is done by first integrating the GSM which thus provides initial and low spatial resolution model parameters as well as lateral boundary conditions of the RSM. The RSM then predicts regional variations influenced more by the higher resolution orography and other land distributions within the limited but high resolution domain. Both models use the same 28 terrain following sigma layers, the same comprehensive set of physical parameterisation modular packages, and the same diagnostic packages, which provide land surface parameters (e.g. soil wetness, soil temperature, etc.), sensible and latent heat fluxes, radiation fluxes, cloudiness, various three dimensional heating and moisture distributions, max/min temperatures, etc. Global to regional forecasts of the fire weather index and precipitation are currently displayed on our Experimental Climate Prediction Centre web site for several regions (Global, U.S., California, S. California, Hawaii) and several forecast times up to 72 hours after the initial date. The entire globe is shown at 100 km resolution; the entire U.S., including Alaska is shown at 50 km resolution; California is shown at 25 km resolution; Hawaii is shown at 10 km resolution. This global to regional modelling system can be easily moved anywhere else in the world. An experimental mesoscale model is now under development and experimental emergency forecasts at 2 km resolution will also soon be available. Also under development are long range monthly (individual weeks) global to regional forecasts. Examples and validations of these forecasts of fire weather will be provided at the meeting.