A potent upper-level through, an advancing cool front and an influx of deep Gulf moisture will create a volatile mixture for Thursday here in Galveston. Accordingly, the National Weather Service has issued both a Flash Flood Watch and a Hazardous Weather Outlook for most ot southeast Texas, including Galveston Island.

This outlook means that the first couple of days of the Lone Star Biker Rally may be a little messy, as rains linger through Friday. On the positive side, it stills seems fairly likely that the rains will move out of the picture by Saturday and the Rally may end up with sunny skies and cool temperatures.

In any case, those arriving early for the Rally may wish to prepare for wet weather through at least the first half of the event. As for Trick or Treaters, it seems that the bad weather should be out of the way in time to allow plenty of fun come Saturday night!

This surface map shows the cool front moving towards the coast on Thrusday:

Meanwhile a deep low pressure trough slowly heads east, promoting a strong southwesterly wind flow at the upper-levels over southeast Texas:

This combination should result in heavy rain over east and southeat Texas: