A natural extension of the H-E is its evolution into an automatic H-E Nowcaster. However, this is not an easy task since one of the greatest challenges of an operational meteorologist is the short term prediction of the direction and speed of movement of Mesoscale Convective Systems (MCS). Propagation is the controlling influence on the movement of MCSs. At this time, the mechanisms of storm propagation are minimally understood. Any 3 hour Nowcast algorithm must take into account propagation characteristics of MCSs. In the spirit of NCAR's (National Center for Atmospheric Research) radar-driven Auto-nowcast system, an initial attempt at developing a satellite-driven H-E Nowcaster is presented. The following briefly describes the H- E Nowcaster process: (a) the speed and direction of the coldest portions (or most active) of the convective systems are measured on the latest satellite imagery; (b) this speed and direction are used to extrapolate the current estimated rainfall rates from the H-E out to 3 hours; (c) in forward propagating events, heaviest rainfall areas are correlated best to the mean cloud-layer shear vector (i.e., moves in the direction of 850-300 thickness isopleths, (d) for regenerative convective systems (e.g. back building, quasi-stationary, forward moving meso beta) (Corfidi et al, Chappell, Shi and Scofield) the growth and movement of individual clusters must be considered in the computation process, and (5) trend and expectancy guidelines are used to anticipate the evolution of the convective systems for the next 3 hours and are used to adjust the extrapolated rainfall. In addition to the GOES (Geostationary Operational environmental Satellite) infrared (IR) and visible (VIS) imagery and various POES (polar orbiting environmental satellite) microwave data, the H-E Nowcaster will make use of 6.7 um GOES Water Vapor imagery, GOES derived products and Sounder data, SSM/I data, the NOAA 15/16 AMSU, and TRMM data, and blends of various satellite data. WSR-88D data will assist in the diagnostics of storm evolution and be used as a boundary detector to help determine where MCS will propagate.
Home pages that contain automatic Flash flood estimates (around the world) and future Nowcasts are on the NESDIS Flash Flood Home Page: "http://orbit35i.nesdis.noaa.gov/arad/ht/ff".