MARWORDS is a natural language text generation system which has been developed to synthesize marine forecasts for the Davis Strait area in Northern Canada. It uses standard manually produced predictions of wind speed, air temperature, and other weather conditions to generate English language text forecasts. The resulting text compares favorably with those written by marine weather specialists. MARWORDS incorporates a detailed grammar to capture the constraints on words, sentences, and texts that are natural to the domain. This grammar was developed from a study of approximately 50 000 words of forecast text. Among the problems faced were the linguistic treatment of data-salience relations and the modulation of temporal adverbs to reflect increasing levels of uncertainty for more remote events. In addition the system was designed so that it could be extended to synthesize bilingual (French and English) or multilingual forecasts.