Van Leer - Henschen PR Forecast

Puerto Rico Forecast Analysis - valid 4pm EST 1 March 2011

The main focus for this forecast lies in a precipitation event that will move through the area on Friday. This precipitation is associated with a pressure trough that is moving off of the East Coast. The GFS HD 12Z showed a significant amount of precipitation for the typically dry early spring season. The calculation that was performed involved the Trenberth form of the QG omega equation. The by hand calculation was performed using the figure showing the geostrophic relative vorticity and 1000-500mb thickness. The value calculated was in the range of -2 x 10-8 Pa/s. While the gaussian smoothed GEMPAK field showed a value of about -10 x 10-10 Pa/s for omega. This support a forecast for precipitation that is called for in the model.