A flash flood watch (SAME code: FFA; also referred as a "green box" by meteorologists) is issued by the National Weather Service when conditions are favorable for flash flooding in flood-prone areas, usually when grounds are already saturated from recent rains, or when upcoming rains will have the potential to cause a flash flood. These watches are also occasionally issued when a dam may break in the near future.
Contents
Countries such as Australia also issue similarly worded warnings.
Example Flash Flood Watch
421 WGUS61 KCLE 230740FFACLEURGENT - IMMEDIATE BROADCAST REQUESTEDFLOOD WATCHNATIONAL WEATHER SERVICE CLEVELAND OH340 AM EDT SAT JUL 23 2011OHZ003-006>013-017>023-027>033-036>038-047-231545-/O.NEW.KCLE.FF.A.0002.110723T0800Z-110724T1000Z//00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/LUCAS-WOOD-OTTAWA-SANDUSKY-ERIE OH-LORAIN-CUYAHOGA-LAKE-GEAUGA-HANCOCK-SENECA-HURON-MEDINA-SUMMIT-PORTAGE-TRUMBULL-WYANDOT-CRAWFORD-RICHLAND-ASHLAND-WAYNE-STARK-MAHONING-MARION-MORROW-HOLMES-KNOX-INCLUDING THE CITIES OF...TOLEDO...BOWLING GREEN...PORT CLINTON...FREMONT...SANDUSKY...LORAIN...CLEVELAND...MENTOR...CHARDON...FINDLAY...TIFFIN...NORWALK...MEDINA...AKRON...RAVENNA...WARREN...UPPER SANDUSKY...CAREY...BUCYRUS...MANSFIELD...ASHLAND...WOOSTER...CANTON...YOUNGSTOWN...MARION...MOUNT GILEAD...MILLERSBURG...MOUNT VERNON340 AM EDT SAT JUL 23 2011...FLASH FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...THE NATIONAL WEATHER SERVICE IN CLEVELAND HAS ISSUED A* FLASH FLOOD WATCH FOR PORTIONS OF NORTH CENTRAL OHIO... NORTHEAST OHIO AND NORTHWEST OHIO...INCLUDING THE FOLLOWING AREAS...IN NORTH CENTRAL OHIO...ASHLAND...CRAWFORD...ERIE OH... HURON...KNOX...LORAIN...MARION...MORROW AND RICHLAND. IN NORTHEAST OHIO...CUYAHOGA...GEAUGA...HOLMES...LAKE... MAHONING...MEDINA...PORTAGE...STARK...SUMMIT...TRUMBULL AND WAYNE. IN NORTHWEST OHIO...HANCOCK...LUCAS...OTTAWA... SANDUSKY...SENECA...WOOD AND WYANDOT. * THROUGH LATE TONIGHT* SHOWERS AND THUNDERSTORMS ARE LIKELY TODAY AND SOME OF THE THUNDERSTORMS WILL HAVE HEAVY RAIN. RECENT RAINS HAVE MADE THE GROUND WET...AND ANY ADDITIONAL HEAVY RAIN WILL BRING THE POTENTIAL FOR FLOODING. * THERE IS ALSO A CHANCE FOR REPEAT THUNDERSTORMS TODAY AND TONIGHT. AREAS THAT GET MULTIPLE THUNDERSTORMS WILL BE AT RISK FOR FLOODING.PRECAUTIONARY/PREPAREDNESS ACTIONS...A FLASH FLOOD WATCH MEANS THE THREAT OF FLASH FLOODING EXISTSALONG RIVERS AND CREEKS AND LOW LYING AREAS. IF YOU ARE IN THEWATCH AREA YOU SHOULD MONITOR WEATHER CONDITIONS CLOSELY. BE READYTO MOVE TO HIGHER GROUND IF FLOODING IS OBSERVED OR A WARNING ISISSUED. STAY TUNED TO WEATHER RADIO FOR FURTHER UPDATES.&&$$PDS watches
In the event that a flash flood watch is likely to lead to a major flash flood disaster, enhanced wording with the words This is a particularly dangerous situation (PDS) can be added to the watch; this is occasionally issued.
References
Flash flood watch Wikipedia(Text) CC BY-SA