Coastal flood watch

A coastal flood watch is issued by the National Weather Service of the United States when coastal flooding along the coast of the Atlantic Ocean, Pacific Ocean, or the Gulf of Mexico is possible. The flooding must be due to water being forced from the nearby body of water onto land, and not from rainfall. Nor'easters, hurricanes, tropical storms, and thunderstorms can all lead to the issuance of a coastal flood watch.^[1]

Example

The following is an example of a coastal flood watch issued by the National Weather Service office in Norton, Massachusetts.^[2]

 462 WHUS41 KBOX 130725 CFWBOX URGENT - IMMEDIATE BROADCAST REQUESTED Coastal Hazard Message National Weather Service Boston/Norton MA 325 AM EDT Mon Mar 13 2023 MAZ007-015-016-019-022-132030- /O.NEW.KBOX.CF.A.0001.230315T0700Z-230315T1200Z/ Eastern Essex MA-Suffolk MA-Eastern Norfolk MA- Eastern Plymouth MA-Barnstable MA- 325 AM EDT Mon Mar 13 2023 ...COASTAL FLOOD WATCH IN EFFECT FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING... * WHAT...Up to one foot of inundation above ground level possible in low-lying areas near shorelines and tidal waterways (2.1 to 12.9 feet Mean Lower Low Water). * WHERE...Eastern Massachusetts coast from the Merrimack River to Cape Cod. * WHEN...From late Tuesday night through Wednesday morning. * IMPACTS...Flooding is up to one foot deep and affects more vulnerable shore roads, including Morrissey Boulevard in Boston. * ADDITIONAL DETAILS...Large waves may produce pockets of moderate flooding along the ocean shoreline in places such as Gloucester, Revere, Hull, and Scituate. Flooding could be 1 to 2 feet deep in some locations and debris could wash onto coastal roadways. Significant beach erosion is also possible. PRECAUTIONARY/PREPAREDNESS ACTIONS... If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property. && && Time of high total tides are approximate to the nearest hour. Gloucester Harbor MLLW Categories - Minor 11.5 ft, Moderate 13.0 ft, Major 15.0 ft MHHW Categories - Minor 2.0 ft, Moderate 3.5 ft, Major 5.5 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 10.2/10.7 0.7/ 1.1 0.8/ 1.3 6 None 13/04 PM 8.9/ 9.4 -0.7/-0.2 0.6/ 1.1 5-6 None 14/05 AM 10.4/10.9 0.9/ 1.4 1.1/ 1.6 6-8 None 14/05 PM 10.0/10.5 0.5/ 1.0 2.0/ 2.5 13-17 None 15/06 AM 10.7/11.2 1.2/ 1.7 1.5/ 2.0 12-15 Minor 15/06 PM 8.9/ 9.4 -0.7/-0.2 1.0/ 1.5 8-10 None Merrimack River near Newburyport MA MLLW Categories - Minor 11.0 ft, Moderate 12.0 ft, Major 13.5 ft MHHW Categories - Minor 1.5 ft, Moderate 2.5 ft, Major 4.0 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 9.2/ 9.7 -0.3/ 0.2 0.8/ 1.3 5 None 13/05 PM 8.1/ 8.6 -1.5/-1.0 0.7/ 1.1 5 None 14/05 AM 9.5/10.0 0.0/ 0.5 1.1/ 1.6 4-5 None 14/05 PM 9.0/ 9.5 -0.6/-0.1 2.1/ 2.6 8-10 None 15/06 AM 10.0/10.5 0.5/ 1.0 1.6/ 2.0 9-10 Minor 15/07 PM 7.8/ 8.4 -1.7/-1.2 0.9/ 1.4 5-7 None Boston Harbor MLLW Categories - Minor 12.5 ft, Moderate 14.0 ft, Major 15.0 ft MHHW Categories - Minor 2.4 ft, Moderate 3.9 ft, Major 4.9 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 10.6/11.1 0.5/ 1.0 0.8/ 1.3 1 None 13/04 PM 9.4/ 9.9 -0.8/-0.2 0.7/ 1.1 2 None 14/05 AM 11.0/11.5 0.9/ 1.4 1.3/ 1.8 2 None 14/05 PM 10.4/10.9 0.2/ 0.8 2.0/ 2.5 2 None 15/06 AM 12.3/12.8 2.2/ 2.7 2.6/ 3.1 2 Minor 15/06 PM 9.3/ 9.8 -0.9/-0.4 1.1/ 1.6 2 None Revere MLLW Categories - Minor 12.5 ft, Moderate 14.5 ft, Major 16.0 ft MHHW Categories - Minor 2.6 ft, Moderate 4.6 ft, Major 6.1 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 10.6/11.1 0.7/ 1.1 0.8/ 1.3 1 None 13/04 PM 9.3/ 9.8 -0.7/-0.2 0.7/ 1.1 1-2 None 14/04 AM 10.8/11.3 0.9/ 1.4 1.2/ 1.7 2 None 14/05 PM 10.2/10.7 0.2/ 0.8 1.9/ 2.3 2 None 15/05 AM 12.1/12.6 2.2/ 2.7 2.6/ 3.1 2 Minor-Mdt 15/06 PM 9.1/ 9.6 -0.9/-0.4 1.1/ 1.6 2 None Scituate MA MLLW Categories - Minor 11.5 ft, Moderate 13.5 ft, Major 15.5 ft MHHW Categories - Minor 1.8 ft, Moderate 3.8 ft, Major 5.8 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 10.2/10.7 0.5/ 1.0 0.8/ 1.3 5 None 13/04 PM 9.0/ 9.5 -0.8/-0.2 0.7/ 1.1 5 None 14/05 AM 10.6/11.1 0.9/ 1.4 1.2/ 1.7 5-7 None 14/05 PM 10.1/10.6 0.4/ 0.9 2.0/ 2.5 11-14 None 15/06 AM 12.0/12.5 2.2/ 2.7 2.6/ 3.1 11-13 Minor-Mdt 15/06 PM 9.1/ 9.6 -0.7/-0.2 1.2/ 1.7 7-8 None Buzzards Bay at Woods Hole MLLW Categories - Minor 5.5 ft, Moderate 7.0 ft, Major 8.5 ft MHHW Categories - Minor 3.5 ft, Moderate 5.0 ft, Major 6.5 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/01 PM 2.5/ 3.0 0.5/ 1.0 0.7/ 1.1 2-3 None 14/01 AM 3.4/ 3.9 1.4/ 1.9 1.3/ 1.8 4 None 14/01 PM 2.7/ 3.2 0.8/ 1.3 1.3/ 1.8 4 None 15/02 AM 1.9/ 2.3 -0.2/ 0.3 -0.2/ 0.2 6-7 None 15/03 PM 2.3/ 2.8 0.4/ 0.9 0.7/ 1.1 5 None Chatham MA - East Coast MLLW Categories - Minor 9.0 ft, Moderate 11.5 ft, Major 13.0 ft MHHW Categories - Minor 1.3 ft, Moderate 3.8 ft, Major 5.3 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 5.9/ 6.4 -1.9/-1.4 0.8/ 1.3 5-6 None 13/05 PM 4.7/ 5.2 -3.0/-2.5 0.7/ 1.1 5-6 None 14/05 AM 6.2/ 6.7 -1.6/-1.1 1.1/ 1.6 7-9 None 14/06 PM 5.0/ 5.5 -2.7/-2.2 1.0/ 1.5 13-14 None 15/06 AM 6.4/ 6.9 -1.4/-0.9 1.3/ 1.8 12 None 15/07 PM 5.1/ 5.6 -2.7/-2.2 1.2/ 1.7 9-10 None Chatham - South side MLLW Categories - Minor 9.0 ft, Moderate 10.5 ft, Major 11.5 ft MHHW Categories - Minor 4.5 ft, Moderate 6.0 ft, Major 7.0 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 4.7/ 5.2 0.2/ 0.8 0.8/ 1.3 4-5 None 13/05 PM 4.0/ 4.5 -0.6/-0.1 0.8/ 1.3 4-5 None 14/06 AM 5.2/ 5.7 0.8/ 1.3 1.2/ 1.7 6-8 None 14/06 PM 4.2/ 4.7 -0.3/ 0.2 1.1/ 1.6 10-13 None 15/06 AM 5.2/ 5.7 0.8/ 1.3 1.1/ 1.6 10-11 None 15/07 PM 4.2/ 4.7 -0.3/ 0.2 1.1/ 1.6 7-9 None Provincetown Harbor MLLW Categories - Minor 13.0 ft, Moderate 14.0 ft, Major 15.0 ft MHHW Categories - Minor 2.9 ft, Moderate 3.9 ft, Major 4.9 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 10.7/11.2 0.6/ 1.1 0.8/ 1.3 4 None 13/04 PM 9.4/ 9.9 -0.8/-0.2 0.6/ 1.1 4 None 14/05 AM 10.8/11.3 0.7/ 1.1 0.9/ 1.4 6-8 None 14/05 PM 10.8/11.3 0.7/ 1.1 2.2/ 2.7 12-19 None 15/06 AM 12.5/13.0 2.3/ 2.8 2.6/ 3.1 13-15 None 15/06 PM 9.6/10.1 -0.6/-0.1 1.3/ 1.8 9-11 None Dennis - Sesuit Harbor MLLW Categories - Minor 13.0 ft, Moderate 14.5 ft, Major 16.0 ft MHHW Categories - Minor 2.5 ft, Moderate 4.0 ft, Major 5.5 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 11.1/11.6 0.6/ 1.1 0.9/ 1.4 3 None 13/04 PM 9.6/10.1 -1.0/-0.5 0.6/ 1.1 3-4 None 14/05 AM 11.0/11.5 0.5/ 1.0 0.9/ 1.4 4-6 None 14/05 PM 11.2/11.7 0.7/ 1.1 2.3/ 2.8 7-10 None 15/06 AM 12.7/13.2 2.2/ 2.7 2.6/ 3.1 8-9 Minor-Mdt 15/06 PM 10.1/10.6 -0.5/ 0.0 1.5/ 2.0 6-7 None Sandwich Harbor MLLW Categories - Minor 12.0 ft, Moderate 14.0 ft, Major 15.0 ft MHHW Categories - Minor 1.7 ft, Moderate 3.7 ft, Major 4.7 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/04 AM 9.5/10.0 -0.9/-0.4 0.8/ 1.3 4 None 13/04 PM 8.3/ 8.8 -2.0/-1.6 0.7/ 1.1 3-4 None 14/05 AM 9.8/10.3 -0.6/-0.1 1.2/ 1.7 3-5 None 14/05 PM 9.5/10.0 -0.9/-0.4 2.1/ 2.6 6-10 None 15/06 AM 11.2/11.7 0.9/ 1.4 2.6/ 3.1 8-9 Minor 15/06 PM 8.7/ 9.2 -1.7/-1.2 1.4/ 1.9 6-7 None Wings Neck MLLW Categories - Minor 6.5 ft, Moderate 9.0 ft, Major 11.5 ft MHHW Categories - Minor 2.1 ft, Moderate 4.6 ft, Major 7.1 ft Total Total Departure Day/Time Tide Tide from Norm Waves Flood ft MLLW ft MHHW ft ft Impact -------- --------- --------- --------- ------- -------- 13/01 PM 4.0/ 4.5 -0.5/ 0.0 0.8/ 1.3 3 None 14/02 AM 5.0/ 5.5 0.6/ 1.1 1.2/ 1.7 3 None 14/01 PM 4.2/ 4.7 -0.2/ 0.2 1.4/ 1.9 3 None 15/02 AM 4.0/ 4.5 -0.3/ 0.2 0.2/ 0.8 4 None 15/03 PM 3.7/ 4.2 -0.7/-0.2 0.7/ 1.1 5 None && $$ 

^[3]

See also

• Severe weather terminology (United States)

References

1. National Weather Service. "Coastal Flood Watch". Glossary - JetStream - Online School for Weather. Retrieved 17 May 2011.
2. National Weather Service. "Coastal Flood Watch". Iowa Environmental Mesonet NWS Product Archive. Retrieved 17 May 2011.
3. herzmann, daryl. "IEM :: Valid Time Event Code (VTEC) App". mesonet.agron.iastate.edu. Retrieved 2023-06-02.

External links

• National Weather Service