36-hour forecast of Hurricane Frances generated by the 20-km CRAS model valid 00UTC September 5, 2004. The actual storm location is denoted by the yellow symbol. Moisture and clouds in the CRAS are initialized using information from the GOES sounders.
The realtime 61km CRAS forecast is capable of predicting the track of hurricanes when they fall within the model domain. Scientists at the Cooperative Institute for Meteorological Studies (CIMSS) are examining how information from satellites might influence hurricane track forecasts. The successive 69 hour forecast tracks below are generated from the realtime 61 kilometer CRAS forecasts that update every 12 hours. A 12 hour forecast spinnup proceedure that incorporates moisture and cloud information from the GOES sounders is used to initialize the moisture fields used by the CRAS.
The forecast positions from successive CRAS forecasts are shown in the animations below. Hurricane locations are computed based on the maximum vorticity at 850hPa. Each forecast track starts with the initial location at either 00UTC or 12UTC, followed by the 3-hour position, and 6 hourly positions out to 69 hours. This is done to match the 03UTC, 09UTC, 15UTC, and 21UTC positions indicated by the Tropical Prediction Center (TPC).
A 20-km CRAS nest was run for Frances at 12UTC 03Sep04 to determine if the CRAS physics could accurately simulate cloud and precipitation features. Animations are available at the link below.