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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.[1]

Countries such as Australia also issue similarly worded warnings.[2]

Contents

Example Flash Flood WatchEdit

Below is an example issued by the National Weather Service in Cleveland, Ohio.


421 
WGUS61 KCLE 230740
FFACLE

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE CLEVELAND OH
340 AM EDT SAT JUL 23 2011

OHZ003-006>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 VERNON
340 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 EXISTS
ALONG RIVERS AND CREEKS AND LOW LYING AREAS. IF YOU ARE IN THE
WATCH AREA YOU SHOULD MONITOR WEATHER CONDITIONS CLOSELY. BE READY
TO MOVE TO HIGHER GROUND IF FLOODING IS OBSERVED OR A WARNING IS
ISSUED. STAY TUNED TO WEATHER RADIO FOR FURTHER UPDATES.

&&

$$

PDS watchesEdit

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. Below is an example issued by the National Weather Service in Memphis, Tennessee.

URGENT - IMMEDIATE BROADCAST REQUESTED
 FLOOD WATCH
 NATIONAL WEATHER SERVICE MEMPHIS TN
 239 PM CDT SUN APR 24 2011
 
 ...VERY HEAVY RAINFALL THROUGH THE MIDDLE OF THIS WEEK WILL LIKELY
 LEAD TO SIGNIFICANT...WIDESPREAD FLASH FLOODING...
 
 ...THIS IS A PARTICULARLY DANGEROUS SITUATION...
 
 A BOUNDARY WILL CONTINUE TO REMAIN STATIONARY ACROSS SOUTHERN
 MISSOURI INTO KENTUCKY THROUGH MONDAY. REPEATED ROUNDS OF
 THUNDERSTORMS WILL TRACK ALONG THE FRONT BRINGING HEAVY RAINFALL.
 THEN A LOW PRESSURE SYSTEM WILL TRACK ALONG IT INTO MISSOURI AND
 PUSH THE FRONT FURTHER SOUTH TO ALONG THE I-40 CORRIDOR MONDAY
 NIGHT THROUGH TUESDAY NIGHT. THIS WILL SHIFT THE HEAVY RAIN AXIS
 FURTHER SOUTH TO ALONG AND JUST NORTH OF THE I-40 CORRIDOR.
 
 A SECOND LOW PRESSURE SYSTEM WILL TRACK ALONG THE NEWLY STALLED
 BOUNDARY AND SET OFF ADDITIONAL TRAINING THUNDERSTORMS LATE
 TUESDAY NIGHT AND WEDNESDAY. THE FINAL COLD FRONT WILL PASS
 THROUGH LATE WEDNESDAY AFTERNOON...ENDING THE PERSISTENT HEAVY
 RAINFALL.
 
 ARZ026>028-035-036-048-049-058-MSZ001>014-TNZ003-004-019>021-
 048>055-088>092-250400-
 /O.NEW.KMEG.FF.A.0007.110426T0000Z-110428T0000Z/
 /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
 CRAIGHEAD-POINSETT-MISSISSIPPI-CROSS- 
 CRITTENDEN-ST. FRANCIS-
 LEE AR-PHILLIPS-DESOTO-MARSHALL-BENTON MS-TIPPAH-ALCORN-
 TISHOMINGO-TUNICA-TATE-PRENTISS- 
 COAHOMA-QUITMAN-PANOLA-LAFAYETTE- 
 
 UNION-WEAKLEY-HENRY-DYER-GIBSON-CARROLL-LAUDERDALE-TIPTON-HAYWOOD-
 CROCKETT-MADISON-CHESTER-HENDERSON- 
 DECATUR-SHELBY-FAYETTE-
 HARDEMAN-MCNAIRY-HARDIN-
 INCLUDING THE CITIES OF...JONESBORO...HARRISBURG...BLYTHEVILLE...
 WYNNE...WEST MEMPHIS...FORREST CITY...HELENA... 
 SOUTHAVEN...
 OLIVE BRANCH...CORINTH...IUKA...TUNICA...[[Booneville, 
 Mississippi|BOONEVILLE]]...
 CLARKSDALE...BATESVILLE...OXFORD...NEW ALBANY... 
 MARTIN...
 DRESDEN...PARIS...DYERSBURG...HUMBOLDT...MILAN...HUNTINGDON...
 COVINGTON...JACKSON...LEXINGTON...BARTLETT...GERMANTOWN...
 COLLIERVILLE...MEMPHIS...MILLINGTON...SOMERVILLE... 
 BOLIVAR...
 SAVANNAH
 239 PM CDT SUN APR 24 2011
 
 ...FLASH FLOOD WATCH IN EFFECT FROM MONDAY EVENING THROUGH
 WEDNESDAY EVENING...
 
 THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A
 
 * FLASH FLOOD WATCH FOR PORTIONS OF EAST ARKANSAS...NORTH MISSISSIPPI
 AND WEST TENNESSEE...INCLUDING THE FOLLOWING AREAS...IN EAST
 ARKANSAS...CRAIGHEAD...CRITTENDEN...CROSS...
 LEE...MISSISSIPPI...PHILLIPS...POINSETT AND ST. FRANCIS. IN
 NORTH MISSISSIPPI...ALCORN...BENTON...COAHOMA...DESOTO...
 LAFAYETTE...MARSHALL...PANOLA...PRENTISS...QUITMAN...TATE...
 TIPPAH...TISHOMINGO...TUNICA AND UNION. IN WEST TENNESSEE...
 CARROLL...CHESTER...CROCKETT...DECATUR...DYER...FAYETTE...
 GIBSON...HARDEMAN...HARDIN...HAYWOOD...HENDERSON...HENRY...
 LAUDERDALE...MADISON...MCNAIRY...SHELBY...TIPTON AND WEAKLEY.
 
 * FROM MONDAY EVENING THROUGH WEDNESDAY EVENING.
 * THIS IS A PARTICULARLY DANGEROUS SITUATION
 * TOTAL RAINFALL AMOUNTS OF 5 TO 8 INCHES ARE EXPECTED ALONG AND
 NORTH OF I-40 WITH 2 TO 5 INCHES EXPECTED SOUTH OF I-40. LOCALLY
 HIGHER AMOUNTS ARE LIKELY.
 
 * RAINFALL AMOUNTS SUCH AS THESE MAY LEAD TO WIDESPREAD...
 SIGNIFICANT...AND LIFE THREATENING FLASH FLOODING. THIS EVENT
 MAY BE AS SEVERE AS THE MAY 1–2, 2010 FLOODING IN PLACES. FLASH
 FLOODING OF CITIES...RURAL AREAS...RIVERS...AND SMALL STREAMS
 ARE POSSIBLE.
 
 PRECAUTIONARY/PREPAREDNESS ACTIONS...
 
 A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
 TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
 
 YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
 SHOULD FLASH FLOOD WARNINGS BE ISSUED.
 
 &&
 
 $$
 
 ARZ008-009-017-018-MOZ113-115-TNZ001-002-250400-
 /O.EXT.KMEG.FF.A.0006.000000T0000Z-110428T0000Z/
 /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
 RANDOLPH-CLAY-LAWRENCE-GREENE-DUNKLIN-PEMISCOT-LAKE-OBION-
 INCLUDING THE CITIES OF...WALNUT RIDGE...PARAGOULD...KENNETT...
 CARUTHERSVILLE...UNION CITY
 239 PM CDT SUN APR 24 2011
 
 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH WEDNESDAY EVENING...
 
 THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR
 
 * PORTIONS OF EAST ARKANSAS...SOUTHEAST MISSOURI AND WEST
 TENNESSEE...INCLUDING THE FOLLOWING AREAS...IN EAST ARKANSAS...
 CLAY...GREENE...LAWRENCE AND RANDOLPH. IN SOUTHEAST MISSOURI...
 DUNKLIN AND PEMISCOT. IN WEST TENNESSEE...LAKE AND OBION.
 
 * THROUGH WEDNESDAY EVENING.
 * THIS IS A PARTICULARLY DANGEROUS SITUATION
 * ADDITIONAL RAINFALL AMOUNTS OF 6 TO 9 INCHES ARE EXPECTED.
 LOCALLY HIGHER AMOUNTS ARE LIKELY. THIS...IN COMBINATION OF
 THE 2 TO 4 INCHES THAT HAVE ALREADY FALLEN MAY LEAD TO TOTAL
 RAINFALL AMOUNTS IN EXCESS OF 12 INCHES IN MANY LOCATIONS.
 
 * RAINFALL AMOUNTS SUCH AS THESE WILL LIKELY LEAD TO WIDESPREAD...
 SIGNIFICANT...AND LIFE THREATENING FLASH FLOODING. THIS EVENT
 MAY BE AS SEVERE AS THE MAY 1-2 2010 FLOODING IN MANY PLACES.
 FLASH FLOODING OF CITIES...RURAL AREAS...RIVERS...AND SMALL
 STREAMS ARE POSSIBLE.
 
 PRECAUTIONARY/PREPAREDNESS ACTIONS...
 
 A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
 TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
 
 YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
 SHOULD FLASH FLOOD WARNINGS BE ISSUED.
 
 &&
 
 $$
 
 BORGHOFF

See alsoEdit

ReferencesEdit

  1. ^ "Flash flood watch definition". Weather.gov. 16 August 2019.
  2. ^ "Flood Warning Services". Bureau of Meteorology. Retrieved 19 June 2014.