With the recent change to Daylight Savings time, most of us in the U.S. have moved an hour closer to Coordinated Universal Time (UTC), more commonly known to meteorologists, aviators, and the military as Zulu (Z) time. Zulu time is based on the time zone that runs through Greenwich, England, and is used to give weather observers and forecasters around the world a common time of reference. Plus, saying Zulu over and over puts a smile on Gothamists face. Upper air observations are made twice a day at 00Z and 12Z (8a.m. and 8 p.m. EDT), with the National Weather Service issuing forecasts based on those, and other observations.
The forecast above is telling us that there is a 90 percent chance of rain for the 24hrs ending tomorrow at 1200 UTC which is 12Z which is 8 a.m. EDT. In other words, it is April, time to get your umbrellas out.