Good afternoon...We're going to begin with current satellite trends. Tropical Storm Issac as of 25/1600Z is moving NNW and is right along the extreme eastern tip of Cuba and about to exit back into open water. On water vapor imagery a good bit of the circulation surrounding the center remains somewhat dry. The big area of convection that is over FL and the surrounding waters is part of the broader circulation of Issac but winds aloft are in excess of 40 knots and are in response to a COL that is between both upper ridges, the long wave trough to the north and the inverted trough associated with Issac to the south; however, winds above 500 millibars are quite strong from the S and SW in response a full latitude longwave trough along the Eastern United States that extends well into the Gulf of Mexico. There is a 200/300 millibar upper high directly over Issac with excellent outflow. The remnants of Joyce are caught up in the Central Atlantic TUTT that extends along and near 52W longtitude to the equator. At 500 millibars there are 588 dm upper highs centered over the central coast of LA with a very narrow ridge axis extending ESE to a 588 upper high over central FL and extending ENE to the Bermuda upper ridge in the AO. The full latitude longwave trough is positive tilted to Jacksonville, FL with a very small upper low which was over SC two days ago, NC yesterday is now centered over VA. The trough inverts from Jacksonville southward to Issac. It should be noted the area that is inverted is elongated from NW to SE which is contributing to convection ongoing near FL at this time. Height falls remain generally neutral but there are slight rises along the Eastern United States east of the trough which are indicative of the trough lifting out and the Bermuda ridge slowly strengthening over the area; it is this that forecasters expect Issac to nudge itself slowly left of current track along with the narrow ridge that is in place west to east across the region N of Issac's track. We think of COLs as an area of weak steering currents but they too are simply like an intersection where multiple players meet as is the case here...Though the track cannot be precise it is clear what it is and where it will go in the broader sense; it becomes a question of what upper ridge at any given time will be the strongest. Another player in this is the shortwave in the middle of the US that is progressing east and will be what turns Issac north in a few days. This system will be welcomed in a good chunk of the country that is in need of making up rainfall deficits; others like N FL and SE GA won't welcome it. I cannot predict whether Issac is to become a major hurricane; there is no evidence to suggest today it will be but the water is hot and the upper air appears favorable for strengthening assuming the trough over the GOM in the upper levels gets out of the way.