If you are not going to use the formatted date in more than one Test Case, then you can simply change from using GlobalVariables to a simple String variable, like below:
Date todaysDate = new Date();
def screenFormattedDate = todaysDate.format("MM/dd/yyyy");
"date of initial inquiry"
WebUI.setText(findTestObject('myPage/input_GeneralInfo.DateInitialInquiry'),
screenFormattedDate)
"click on another area of the page to let the calendar GUI disappear"
WebUI.click(findTestObject('myPage/textarea_GeneralInfo.Location'))
"verify the date is set"
WebUI.verifyElementAttributeValue(findTestObject('myPage/input_GeneralInfo.DateInitialInquiry'),
"value", screenFormattedDate, 10)