High Tide Bulletin: Fall 2020

When you may experience higher than normal tides between September and November 2020.

The rising and falling of the sea is a phenomenon upon which we can always depend. Tides are the regular rise and fall of the sea surface caused by the gravitational pull of the moon and sun and their position relative to the earth. There are some factors that cause the tides to be higher than what is "normally" seen from day to day. This bulletin tells you when you may experience higher than normal high tides for the period of time between between September and November 2020.

We also publish annual high tide flooding reports that present a broad outlook of what to expect for a given year in terms of high tide flooding, as well as a summary of high tide flooding events for the previous calendar year.

Regional outlook map

Select a region below to see when you may experience higher than normal tides from September and November 2020. Depending on non-tidal conditions (wind, storms, etc.), regions may experience impacts before or after the dates mentioned here.

Higher than normal high tides alone do not necessarily cause coastal flooding. However, they are becoming increasingly impactful due to continued sea level rise. High tide flooding that inundates busy streets, and washes out beaches is more likely to occur during these periods depending on your location along the coast. More severe flooding may result if adverse weather — heavy rains, strong wind or big waves — conditions are present.

Northeast outlook

Includes Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, and New York

When will the tides be higher than normal?

  • September 17-21
  • October 16-20
  • November 14-18

Why will they be higher than normal?

  • Mean sea level is generally higher in the early fall months in the northeast due to warmer, expanding ocean water and changes in weather patterns.
  • A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth. Higher than normal high tides and lower than normal low tides will occur.
  • In October and November, some locations along the Northeast coast are predicted to exceed the high tide flooding threshold based on tides alone.

What kind of impact might I expect along the coast?

  • Due to the topography of the northeast (less low lying areas), high tides alone will not likely cause a significant impact on the coast unless accompanied by storm or strong winds.

Where might I expect high tide flooding?

Tide stations at the following locations have the greatest chance of seeing high tide flooding:

  • Kings Point, New York.; Providence, Rhode Island; Boston, Massachusetts;Bar Harbor, Maine.

Regional outlook Text Only

Northeast outlook

When will the tides be higher than normal?

  • September 17-21
  • October 16-20
  • November 14-18

Why will they be higher than normal?

  • Mean sea level is generally higher in the early fall months in the northeast due to warmer, expanding ocean water and changes in weather patterns.
  • A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth. Higher than normal high tides and lower than normal low tides will occur.
  • In October and November, some locations along the Northeast coast are predicted to exceed the high tide flooding threshold based on tides alone.

What kind of impact might I expect along the coast?

  • Due to the topography of the northeast (less low lying areas), high tides alone will not likely cause a significant impact on the coast unless accompanied by storm or strong winds.

Where might I expect high tide flooding?

Tide stations at the following locations have the greatest chance of seeing high tide flooding:

  • Kings Point, New York.; Providence, Rhode Island; Boston, Massachusetts;Bar Harbor, Maine.

Mid-Atlantic outlook

Includes New Jersey, Delaware, Pennsylvania, Maryland, District of Columbia, Virginia.

When will the tides be higher than normal?

  • September 16-22
  • October 15-20
  • November 14-18

Why will they be higher than normal?

  • Mean sea level is generally higher in the early fall months in the Mid Atlantic due to warmer, expanding ocean water and changes in weather patterns.
  • A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth. Higher than normal high tides and lower than normal low tides will occur.

What kind of impact might I expect along the coast?

  • Minor tidal flooding along the coast, in particular in low-lying areas.
  • If a storm occurs at this time, increased levels of tidal flooding and coastal erosion may occur.
  • Lower than normal low tides will also occur.

Where might I expect high tide flooding?

Tide stations at the following locations have the greatest chance of seeing high tide:

  • The Battery, New York; Bergen Point, New York; Sandy Hook, New Jersey; Cape May, New Jersey; Lewes, Delaware; Sewell’s Point, Virgina

Southeast outlook

Includes North Carolina, South Carolina, Georgia, Eastern Florida coast.

When will the tides be higher than normal?

  • September 15-21
  • October. 14-21
  • November 13-18

Why will they be higher than normal?

  • Mean sea level is generally higher in the fall in the Southeast due to changing weather patterns and typical short-term decreases in Gulf Stream transport.
  • A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth, higher than normal high tides and lower than normal low tides will occur.
  • In October and November, some locations along the Southeast coast are predicted to exceed the high tide flooding threshold based on tides alone.

What kind of impact might I expect along the coast?

  • Minor tidal flooding along the coast, in particular in low-lying areas.
  • If a storm occurs at this time, increased levels of tidal flooding and coastal erosion may occur.
  • Lower than normal low tides will also occur.

Where might I expect high tide flooding?

Tide stations at the following locations have the greatest chance of seeing high tide flooding:

  • Myrtle Beach, SC; Charleston, SC; Fort Pulaski, GA; Fernandina Beach, FL; Mayport, FL; Port Canaveral, FL

Gulf Coast outlook

Includes Texas, Louisiana, Mississippi, Alabama, Western Florida coast.

When will the tides be higher than normal?

  • The Gulf Coast will not be significantly impacted.

Why won’t they be impacted?

  • In many locations of the Gulf Coast, the tidal range is relatively small compared to other regions of the U.S, so they will not be as significantly impacted by a perigean spring tide.

West Coast outlook

Includes California, Oregon, Washington State.

When will the tides be higher than normal?

  • October 17-19
  • November 13-18

Why will they be higher than normal?

  • Mean sea level is generally higher in the early fall months along the southern west coast due to warmer, expanding ocean water and changes in weather patterns.
  • A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth. Higher than normal high tides and lower than normal low tides will occur.
  • In November, some locations along the West Coast are predicted to exceed the high tide flooding threshold based on tides alone.

Hawaii and the Pacific Islands outlook

Includes Hawaii, Guam, American Samoa, Midway, Kwajalein, and Wake Island.

When will the tides be higher than normal?

  • October 16-19
  • November 14-18

Why will they be higher than normal?

  • A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth. Higher than normal high tides and lower than normal low tides will occur.

Where might I expect High Tide Flooding?

  • Tide stations at the following locations have the greatest chance of seeing high tide flooding - Kwajalein, Marshall Islands.

ALASKA outlook

When will the tides be higher than normal?

  • October 16-20
  • November 13-18

Why will they be higher than normal?

  • A perigean spring tide will be occurring. This is when the moon is either new or full and
  • closest to earth, higher than normal high tides and lower than normal low tides will occur.

What kind of impact might I expect along the coast?

  • Due to the topography, in particular for southeast Alaska (less low lying areas), tidal flooding will generally not have a significant impact on the coast unless there is a severe storm.
high tide flooding (King Tide) in Washington State

View the latest report summarizing high tide flooding events in 2019 and our high tide flooding outlook through April 2021. The report is based on new, national flooding thresholds. It focuses on more impactful, deeper floods at some locations and expands the outlook to about 100 coastal locations.

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Last updated:
09/01/20

Author: NOAA

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