A weak cool front is pushing through and with our winds turning into the north cooler, less humid air is coming in.  Along the front there are some showers that have formed and there are likely to be more, primarily south of DC later this afternoon.  Meanwhile the National Hurricane Center has upgraded Isaac to a weak category one hurricane with maximum sustained winds of 75 mph.  The biggest risk is still a storm surge of 5-10 feet along the Louisiana-Mississippi Gulf and flooding rains.  There is still NO SIGN that what is left of Isaac will have any significant impact on our weather.  There is a slight chance of some showers late Saturday or Sunday if some Isaac moisture slides to our north.  More likely, high pressure over us into Saturday.