Flash flood watch

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A Flash flood watch is issued when conditions are favorable for flash flooding in flood-prone areas where grounds are already saturated from recent rains.

The Storm Prediction Center does not issue those watches, only National Weather Service offices can do so.

==Example of a Flash Flood Watch:

FLOOD WATCH
NATIONAL WEATHER SERVICE SAN JUAN PR
1037 AM AST SAT MAY 3 2008

PRZ001>011-040245-
/O.EXT.TJSJ.FF.A.0002.000000T0000Z-080504T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN JUAN AND VICINITY-NORTHEAST-SOUTHEAST-EASTERN INTERIOR-
NORTH CENTRAL-CENTRAL INTERIOR-PONCE AND VICINITY-NORTHWEST-
WESTERN INTERIOR-MAYAGUEZ AND VICINITY-SOUTHWEST-
INCLUDING THE MUNICIPALITIES AND/OR ISLANDS OF...SAN JUAN...
CAROLINA...FAJARDO...HUMACAO...GUAYAMA...ARROYO...YABUCOA...
SALINAS...COCO...CAGUAS...ARECIBO...VEGA BAJA...DORADO...COAMO...
COROZAL...AIBONITO...VILLALBA...JAYUYA...PONCE...AGUADILLA...
ISABELA...HATILLO...QUEBRADILLAS...UTUADO...SABANA GRANDE...LARES...
ADJUNTAS...HORMIGUEROS...MOCA...AGUADA...LUYANDO...CABO ROJO...LAJAS
1037 AM AST SAT MAY 3 2008

...FLASH FLOOD WATCH NOW IN EFFECT THROUGH THIS EVENING...

THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR

* ALL OF PUERTO RICO

* THROUGH 11 PM THIS EVENING

* THE RAPID APPROACH OF ANOTHER MID TO UPPER LEVEL SHORT WAVE
  TROUGH DIGGING SOUTHEAST TOWARDS THE REGION...AND THE PROXIMITY
  OF A SURFACE TROUGH SINKING SOUTH ACROSS THE DOMINICAN REPUBLIC
  AND THE MONA PASSAGE...COMBINED WITH ABUNDANT LOW LEVEL TROPICAL
  MOISTURE AND DIURNAL AND LOCAL ISLAND EFFECTS...WILL AGAIN RESULT
  IN THE DEVELOPMENT OF SCATTERED TO NUMEROUS SHOWERS AND
  THUNDERSTORMS...SOME WITH VERY HEAVY RAINFALL ACROSS PUERTO RICO
  AT LEAST THROUGH THIS AFTERNOON. IN ADDITION...GROUNDS ACROSS THE
  WATCH AREA REMAIN AT OR NEAR SATURATION AND MANY RIVERS REMAIN AT
  ABOVE NORMAL LEVELS ESPECIALLY ALONG THE NORTHERN AND EAST
  SECTION OF THE ISLAND.

* ADDITIONAL RAINFALL OF 1 TO 3 INCHES...WITH LOCALLY HIGHER
  AMOUNTS POSSIBLY OVER 5 INCHES ARE EXPECTED OVER PARTS OF PUERTO RICO
  THROUGH THIS AFTERNOON AS SHOWERS ACTIVITY MAY RAPIDLY BE
  ENHANCED WITH THE DAYTIME HEATING. THIS RAINFALL COULD RESULT IN
  ADDITIONAL FLASH AND RIVER FLOODING. ALSO...ROCK AND MUDSLIDES
  (DEBRIS FLOW) ARE POSSIBLE OVER AREAS OF STEEP TERRAIN.

A FLASH FLOOD WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR HEAVY
RAIN ACROSS THE WATCH AREA...WHICH MAY LEAD TO FLOODING. IF YOU ARE
IN THE WATCH AREA...CHECK YOUR PREPAREDNESS REQUIREMENTS...ESPECIALLY
IF YOU HAVE INTERESTS ALONG AREA RIVERS. KEEP INFORMED... AND BE
READY FOR QUICK ACTION IF FLOODING IS OBSERVED OR IF A FLASH FLOOD
WARNING IS ISSUED.

PEOPLE IN THE WATCH AREA SHOULD CONTINUE TO BE AWARE OF THE
POSSIBILITY FOR HEAVY RAINFALL. AVOID LOW LYING AREAS...AND BE
CAREFUL WHEN APPROACHING HIGHWAY DIPS AND UNDERPASSES. ADDITIONAL
HEAVY RAIN MAY CONTINUE TO CAUSE MUDSLIDES IN AREAS OF STEEP
TERRAIN.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL TV...RADIO OR YOUR CABLE
TELEVISION PROVIDER FOR LATER STATEMENTS AND POSSIBLE WARNINGS.

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND CLIMATE
INFORMATION...IS AVAILABLE ON THE WEB AT HTTP://WWW.SRH.NOAA.GOV/SJU
OR AT HTTP://WEATHER.GOV.

$$

[edit] See also