According to Ulster County Emergency Communications./Emergency Management Directory Arthur Snyder, there will be rain moving through the Catskills tonight, and nobody really know how much. From his email earlier today:
Special attention to all those involved in Irene recovery efforts
Here is the latest information from the National Weather Service: Flash flooding threat looks to be an isolated threat. A flood watch will be issued this afternoon. Can expect showers this afternoon with heavier, steadier rain overspreading the area tonight into Wednesday morning. It appears the heaviest rains will occur to our west. Basin average rainfall expected over the next 48 hours is in the 2" range. Higher amounts are possible in the Catskills. Flooding will remain a concern through Thursday. The actual amount of rain to be received over the Catskills is questionable and of the highest concern.
Flood watches have been issued for Delaware, Sullivan, Ulster, Greene and Schoharie counties through tonight.
A look at the hydrographs from the Advanced Hydrologic Prediction Service shows that minor flooding is expected at the Pepacton Reservoir and in Walton in the next 48 hours.