- A surface ridge northwest of Hawaii will bring weak trade winds to western islands this week, while lighter winds and localized breezes affect eastern areas due to a lingering trough near the Big Island. Abundant moisture will provide cloudy and showery weather at times.
- Through the week, above normal moisture and weak winds will persist across the state due to the trough and moisture drifting south, bringing clouds and showers. Gentler trades may return over the weekend as the trough weakens.
- A significant south swell is expected to arrive Saturday and peak Sunday-Monday, potentially reaching advisory levels for south shores. Otherwise surf will remain below levels through the next several days.
- A surface ridge northwest of Hawaii will bring weak trade winds to western islands this week, while lighter winds and localized breezes affect eastern areas due to a lingering trough near the Big Island. Abundant moisture will provide cloudy and showery weather at times.
- Through the week, above normal moisture and weak winds will persist across the state due to the trough and moisture drifting south, bringing clouds and showers. Gentler trades may return over the weekend as the trough weakens.
- A significant south swell is expected to arrive Saturday and peak Sunday-Monday, potentially reaching advisory levels for south shores. Otherwise surf will remain below levels through the next several days.
Tropical revolving storms, also known as tropical cyclones, form over warm ocean waters and have a circular wind pattern that rotates counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. They develop from tropical disturbances and depressions and can intensify into tropical storms or hurricanes/typhoons depending on wind speeds and location. Tropical storms typically form west of continents in tropical regions between 5 degrees north and south latitude from June to November and can cause significant damage due to strong winds and heavy rain.
The document discusses extreme weather events like tornadoes and hurricanes. It describes how tornadoes form from thunderstorms and can range from weak F0 tornadoes to incredibly strong F5 tornadoes. The largest tornado on record was the 1925 Tri-State Tornado that traveled 219 miles across multiple states with winds over 300 mph. Tornadoes are most likely in the central US. Hurricanes form over warm ocean waters and can have winds up to 175 mph, with the strongest recorded being Hurricane Wilma. Hurricanes often impact the US east coast and Gulf Coast.
The document discusses extreme weather events like tornadoes and hurricanes. It describes how tornadoes form from thunderstorms and can range from weak F0 tornadoes to incredibly strong F5 tornadoes. The largest tornado on record was the 1925 Tri-State Tornado that traveled 219 miles across multiple states with winds over 300 mph. Tornadoes are most likely in the central US. Hurricanes form over warm ocean waters and can have winds up to 175 mph, with the strongest recorded being Hurricane Wilma. Hurricanes often impact the US east coast and Gulf Coast.
Hurricanes and tornadoes are both powerful storms that can cause damage. Hurricanes form over warm tropical waters and gain strength from moisture and wind convergence. They are categorized based on wind speeds and can be over 500 miles wide. Tornadoes form from thunderstorms and wind shear, have narrower widths, and last only a few minutes though some may be over a mile wide. Both storms require safety precautions like sheltering indoors away from windows.
Typhoon Haiyan was one of the strongest tropical cyclones on record, devastating portions of Southeast Asia in November 2013. It caused catastrophic destruction in the Philippines, where over 6,300 people were killed. Agricultural areas were heavily impacted, with rice fields, coconut trees, and fishing communities affected. The typhoon destroyed thousands of acres used for rice farming and impacted the livelihoods of over 1 million farmers. Key industries like sugarcane and coconut production also suffered severe damage. Typhoon Haiyan weakened as it moved through Vietnam and dissipated over land on November 11, causing billions in damages across multiple countries.
Typhoon Haiyan formed in November 2013 and struck the Philippines on November 8th as a category 5 typhoon with peak gust speeds of 379 kph, making it one of the strongest storms on record. It affected Southeast Asia, especially the Philippines, Vietnam, and China. Typhoon Haiyan caused over 6,000 deaths, destroyed over 160,000 buildings and 384,000 acres of land, resulting in an estimated $1.5 billion in damages. It was one of the worst typhoons to impact the Philippines.
1) Hurricanes are severe tropical storms that form over warm ocean waters and bring strong winds, heavy rain, and storm surge flooding.
2) They are categorized on a scale of 1 to 5 based on wind speed, with category 3 and above considered major hurricanes.
3) Storm surge, which is increased by hurricane winds, causes the most damage from hurricanes and is the rising of sea water above the normal tide level.
A typhoon is an intense circulating weather system over tropical seas and oceans characterized by very strong winds and heavy rain. Typhoons are categorized into five categories based on wind speed, ranging from a tropical depression with winds under 120 km/h to a violent typhoon with winds over 249 km/h. During a typhoon, people should take precautions like locking windows, clearing drains, listening to weather forecasts, taping windows, and bringing flower pots indoors.
The document discusses typhoons, hurricanes, and cyclones. It explains that they are the same weather phenomenon, but are called different names depending on their geographic location. Typhoons occur in the northwest Pacific, hurricanes in the northeast Pacific and northern Atlantic, and cyclones in other areas. The document also provides details about the Philippine Atmospheric, Geophysical and Astronomical Services Administration's (PAGASA) storm warning signal system, including meteorological conditions and recommended actions for each warning level from 1 to 4.
A tornado is a violently rotating column of air that extends from a thunderstorm to the ground. They come in different shapes and sizes, with wind speeds that can exceed 300 mph. The deadliest tornadoes include the 1925 Tri-State Tornado that killed 695 people across multiple US states over 219 miles, and the 1989 Daulatpur-Saturnia Tornado in Bangladesh that killed over 1,300 people and destroyed 90% of homes across a 50 mile path. Proper tornado safety is to seek shelter in a basement, interior room or the lowest level of a building.
Typhoons are tropical cyclones that originate in the China Sea between July and October. They have strong winds that spiral inward towards the center of the storm. Typhoons can follow straight, recurving, or northward paths, affecting locations like the Philippines, China, Taiwan, Vietnam, Japan, and small Pacific islands. The eye of the typhoon is the calm center of the storm, which can be up to 40 miles wide and surrounded by heavy rain and strong winds.
Weather cells and weather systems of atmosphereSunil Kumar
Jet streams are fast moving air currents in the upper atmosphere. They were first discovered in the 1920s and knowledge of them increased during World War II. There are two main types: polar and subtropical jet streams. Weather features like storms can form when air rises due to low pressure caused by jet streaks. Other weather systems discussed include air masses, frontal systems like cold fronts and warm fronts, mid-latitude cyclones, thunderstorms, tornadoes, and hurricanes.
Chapter 11, Lessons 7 & 8 Air Masses and Fronts; Severe Stormswhitneyhgodfrey
The document discusses different types of air masses and fronts including cold fronts, warm fronts, thunderstorms, tornadoes, hurricanes, and storm surges. It provides descriptions of the key characteristics of each type of weather phenomenon such as how cold fronts bring brief heavy storms while warm fronts bring lighter precipitation over longer periods. Severe storms like hurricanes are described as large swirling storms with low central pressure that can cause storm surges.
The document summarizes key information about tornadoes including their formation, characteristics, warning signs, safety precautions, and common myths. It discusses how tornadoes form due to collisions of warm and cold air masses. They can have wind speeds over 300 mph and occur most frequently in the late afternoon and evening in tornado alley states. The document outlines safety procedures during tornadoes and emphasizes that underground shelters are the safest location to ride out a tornado.
Learning Competencies:
-explain how typhoons develop;
- infer why the Philippines is prone to typhoons;
-explain how landmasses and bodies of water affect typhoons;
According to the document:
- About 20 tropical cyclones enter the Philippine Area of Responsibility each year according to PAGASA.
- Tropical cyclones are categorized as tropical depressions, tropical storms, or typhoons based on their sustained wind speeds.
- The term "typhoon" is used for tropical cyclones that develop in the northwest Pacific Ocean, while similar storms in other regions are called hurricanes.
Severe weather such as thunderstorms, tornadoes, hurricanes, and blizzards can endanger people and cause property damage. Thunderstorms produce heavy rain, lightning, thunder, and sometimes hail. Tornadoes are violent whirling winds that can destroy buildings. Hurricanes are powerful storms that form over warm oceans and can demolish structures. Blizzards occur in winter when winds blow heavy snow, reducing visibility. It is important to take safety precautions like sheltering indoors during storms and listening for watches and warnings.
- A major winter storm was impacting areas of North Texas, southern Oklahoma, and central Arkansas with heavy ice accumulations, dangerous travel conditions, and potential widespread power outages.
- Additional winter weather was forecast for northern and central parts of the region on Saturday into Sunday, with the possibility of more ice accumulation over areas already impacted, though amounts were expected to be relatively light.
- Confidence in the Saturday/Sunday forecast was low, but temperatures were expected to remain at or below freezing in many areas into next week, keeping ice on power lines and surfaces from melting.
Tropical revolving storms, also known as tropical cyclones, form over warm ocean waters and have a circular wind pattern that rotates counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. They develop from tropical disturbances and depressions and can intensify into tropical storms or hurricanes/typhoons depending on wind speeds and location. Tropical storms typically form west of continents in tropical regions between 5 degrees north and south latitude from June to November and can cause significant damage due to strong winds and heavy rain.
The document discusses extreme weather events like tornadoes and hurricanes. It describes how tornadoes form from thunderstorms and can range from weak F0 tornadoes to incredibly strong F5 tornadoes. The largest tornado on record was the 1925 Tri-State Tornado that traveled 219 miles across multiple states with winds over 300 mph. Tornadoes are most likely in the central US. Hurricanes form over warm ocean waters and can have winds up to 175 mph, with the strongest recorded being Hurricane Wilma. Hurricanes often impact the US east coast and Gulf Coast.
The document discusses extreme weather events like tornadoes and hurricanes. It describes how tornadoes form from thunderstorms and can range from weak F0 tornadoes to incredibly strong F5 tornadoes. The largest tornado on record was the 1925 Tri-State Tornado that traveled 219 miles across multiple states with winds over 300 mph. Tornadoes are most likely in the central US. Hurricanes form over warm ocean waters and can have winds up to 175 mph, with the strongest recorded being Hurricane Wilma. Hurricanes often impact the US east coast and Gulf Coast.
Hurricanes and tornadoes are both powerful storms that can cause damage. Hurricanes form over warm tropical waters and gain strength from moisture and wind convergence. They are categorized based on wind speeds and can be over 500 miles wide. Tornadoes form from thunderstorms and wind shear, have narrower widths, and last only a few minutes though some may be over a mile wide. Both storms require safety precautions like sheltering indoors away from windows.
Typhoon Haiyan was one of the strongest tropical cyclones on record, devastating portions of Southeast Asia in November 2013. It caused catastrophic destruction in the Philippines, where over 6,300 people were killed. Agricultural areas were heavily impacted, with rice fields, coconut trees, and fishing communities affected. The typhoon destroyed thousands of acres used for rice farming and impacted the livelihoods of over 1 million farmers. Key industries like sugarcane and coconut production also suffered severe damage. Typhoon Haiyan weakened as it moved through Vietnam and dissipated over land on November 11, causing billions in damages across multiple countries.
Typhoon Haiyan formed in November 2013 and struck the Philippines on November 8th as a category 5 typhoon with peak gust speeds of 379 kph, making it one of the strongest storms on record. It affected Southeast Asia, especially the Philippines, Vietnam, and China. Typhoon Haiyan caused over 6,000 deaths, destroyed over 160,000 buildings and 384,000 acres of land, resulting in an estimated $1.5 billion in damages. It was one of the worst typhoons to impact the Philippines.
1) Hurricanes are severe tropical storms that form over warm ocean waters and bring strong winds, heavy rain, and storm surge flooding.
2) They are categorized on a scale of 1 to 5 based on wind speed, with category 3 and above considered major hurricanes.
3) Storm surge, which is increased by hurricane winds, causes the most damage from hurricanes and is the rising of sea water above the normal tide level.
A typhoon is an intense circulating weather system over tropical seas and oceans characterized by very strong winds and heavy rain. Typhoons are categorized into five categories based on wind speed, ranging from a tropical depression with winds under 120 km/h to a violent typhoon with winds over 249 km/h. During a typhoon, people should take precautions like locking windows, clearing drains, listening to weather forecasts, taping windows, and bringing flower pots indoors.
The document discusses typhoons, hurricanes, and cyclones. It explains that they are the same weather phenomenon, but are called different names depending on their geographic location. Typhoons occur in the northwest Pacific, hurricanes in the northeast Pacific and northern Atlantic, and cyclones in other areas. The document also provides details about the Philippine Atmospheric, Geophysical and Astronomical Services Administration's (PAGASA) storm warning signal system, including meteorological conditions and recommended actions for each warning level from 1 to 4.
A tornado is a violently rotating column of air that extends from a thunderstorm to the ground. They come in different shapes and sizes, with wind speeds that can exceed 300 mph. The deadliest tornadoes include the 1925 Tri-State Tornado that killed 695 people across multiple US states over 219 miles, and the 1989 Daulatpur-Saturnia Tornado in Bangladesh that killed over 1,300 people and destroyed 90% of homes across a 50 mile path. Proper tornado safety is to seek shelter in a basement, interior room or the lowest level of a building.
Typhoons are tropical cyclones that originate in the China Sea between July and October. They have strong winds that spiral inward towards the center of the storm. Typhoons can follow straight, recurving, or northward paths, affecting locations like the Philippines, China, Taiwan, Vietnam, Japan, and small Pacific islands. The eye of the typhoon is the calm center of the storm, which can be up to 40 miles wide and surrounded by heavy rain and strong winds.
Weather cells and weather systems of atmosphereSunil Kumar
Jet streams are fast moving air currents in the upper atmosphere. They were first discovered in the 1920s and knowledge of them increased during World War II. There are two main types: polar and subtropical jet streams. Weather features like storms can form when air rises due to low pressure caused by jet streaks. Other weather systems discussed include air masses, frontal systems like cold fronts and warm fronts, mid-latitude cyclones, thunderstorms, tornadoes, and hurricanes.
Chapter 11, Lessons 7 & 8 Air Masses and Fronts; Severe Stormswhitneyhgodfrey
The document discusses different types of air masses and fronts including cold fronts, warm fronts, thunderstorms, tornadoes, hurricanes, and storm surges. It provides descriptions of the key characteristics of each type of weather phenomenon such as how cold fronts bring brief heavy storms while warm fronts bring lighter precipitation over longer periods. Severe storms like hurricanes are described as large swirling storms with low central pressure that can cause storm surges.
The document summarizes key information about tornadoes including their formation, characteristics, warning signs, safety precautions, and common myths. It discusses how tornadoes form due to collisions of warm and cold air masses. They can have wind speeds over 300 mph and occur most frequently in the late afternoon and evening in tornado alley states. The document outlines safety procedures during tornadoes and emphasizes that underground shelters are the safest location to ride out a tornado.
Learning Competencies:
-explain how typhoons develop;
- infer why the Philippines is prone to typhoons;
-explain how landmasses and bodies of water affect typhoons;
According to the document:
- About 20 tropical cyclones enter the Philippine Area of Responsibility each year according to PAGASA.
- Tropical cyclones are categorized as tropical depressions, tropical storms, or typhoons based on their sustained wind speeds.
- The term "typhoon" is used for tropical cyclones that develop in the northwest Pacific Ocean, while similar storms in other regions are called hurricanes.
Severe weather such as thunderstorms, tornadoes, hurricanes, and blizzards can endanger people and cause property damage. Thunderstorms produce heavy rain, lightning, thunder, and sometimes hail. Tornadoes are violent whirling winds that can destroy buildings. Hurricanes are powerful storms that form over warm oceans and can demolish structures. Blizzards occur in winter when winds blow heavy snow, reducing visibility. It is important to take safety precautions like sheltering indoors during storms and listening for watches and warnings.
- A major winter storm was impacting areas of North Texas, southern Oklahoma, and central Arkansas with heavy ice accumulations, dangerous travel conditions, and potential widespread power outages.
- Additional winter weather was forecast for northern and central parts of the region on Saturday into Sunday, with the possibility of more ice accumulation over areas already impacted, though amounts were expected to be relatively light.
- Confidence in the Saturday/Sunday forecast was low, but temperatures were expected to remain at or below freezing in many areas into next week, keeping ice on power lines and surfaces from melting.
Tropical cyclones that occur in different regions are known by different names. Hurricanes form in the Atlantic Ocean and Northeast Pacific, typhoons form in the Northwest Pacific, and cyclones form in the South Pacific and Indian Ocean. While they have different names depending on their location, they are all essentially the same type of rotating storm system developing over warm ocean waters. The key differences are in the areas they affect and their peak seasons, with hurricanes affecting the Caribbean and US east coast and typhoons affecting Southeast Asia, for example. They are classified using the same wind speed scales to indicate their intensity.
This document summarizes the potential for severe weather in Pennsylvania on Saturday September 8th. A strong cold front is expected to move across the state, bringing the potential for damaging winds, isolated tornadoes, and large hail. The greatest risks are highlighted in a hatched area on a map, where winds over 75 mph, EF2+ tornadoes, and 2 inch hail are possible. The timing of storms is expected to be morning in western PA, mid-afternoon in central areas, and late afternoon in eastern areas. Impacts may include scattered severe storms ahead of the organized line, and brief but heavy rainfall.
1. Hurricanes develop over warm tropical oceans with sea surface temperatures above 26°C.
2. They tend to form in autumn when sea temperatures are highest and in the trade wind belt near the equator.
3. Hurricanes are difficult to predict once formed and can move in erratic patterns over land and water before dissipating without a warm ocean source.
A severe weather event is expected to impact the region late tonight bringing the threat of hail, damaging winds, and tornadoes. A squall line is forecast to develop after dawn along a cold front, posing risks of large hail, tornadoes, and damaging winds through the morning hours as unstable air moves over the region. Flooding is also possible where heavy rain has already fallen. A tornado watch is anticipated to be issued later tonight as conditions become more favorable for severe weather with the passing line of storms.
This document discusses factors that affect climate and weather patterns in the Philippines. It explains that climate is the average weather over time and is influenced by latitude, altitude, proximity to bodies of water, ocean currents, and topography. Temperature and rainfall are most affected by latitude, with equatorial regions experiencing higher temperatures and rainfall. Altitude, land/water distribution, winds, and monsoon patterns also impact regional climates. The Philippines experiences two pronounced monsoon seasons - the northeast monsoon from December to January and the southwest monsoon from July to September.
Tropical revolving storms form between 5 and 20 degrees north and south of the equator, where warm ocean waters above 27°C provide energy. Uneven heating of the atmosphere and Earth's rotation cause winds that lift warm, moist air and release heat energy through condensation, creating the storms. Tropical storms strengthen as they travel over warm ocean waters, gaining wind speed and size, and can produce damaging winds, storm surges, heavy rain, and tornadoes when making landfall.
Tropical cyclones originate over warm tropical oceans and are characterized by low pressure, high winds, and heavy rain in a spiral pattern around a central area that moves in a counter-clockwise direction. They are known as hurricanes, cyclones, or typhoons depending on their location. The Philippines is prone to typhoons due to its location in the western Pacific basin, which has warm ocean temperatures that allow typhoons to form.
El Niño is a weather pattern that occurs every 2-7 years in the Pacific ocean, causing significant changes in weather. It involves a rise in sea surface temperatures of at least 0.5°C in the east-central Pacific for three consecutive months. This disrupts typical wind and pressure patterns, causing warm water that normally moves westward to head east towards South America. The effects of El Niño can last 1-3 years and impact fisheries, agriculture, and precipitation patterns around the world, sometimes causing floods, droughts, wildfires or diseases in lands thousands of miles away from the Pacific. The opposite phenomenon is called La Niña.
Tropical revolving storms, also known as hurricanes, typhoons or cyclones, develop over warm tropical waters and are low pressure systems characterized by strong winds that spiral inward toward the center. The document discusses the local names, areas of formation, and ideal conditions for tropical revolving storms to develop. It also describes their structure, movement, lifespan and associated weather, as well as different classification systems used to categorize their intensity based on wind speeds.
The document summarizes several key influences on Australia's climate, including latitudinal zones, the subtropical ridge and blocking highs, cut off lows like the 2007 Newcastle storm, easterly troughs, the El Niño/La Niña phenomenon, frontal systems, the Indian Ocean Dipole, the monsoon, and northwest cloud bands. It provides details on each influence and how they impact Australia's weather and rainfall patterns.
1) A gale warning has been issued for Irish coastal waters and the Irish Sea, with south to southwest winds reaching gale force at times.
2) Today will be mild and humid with cloudy skies, hill fog, and a risk of coastal fog. Scattered rain and drizzle will spread west and northwest, becoming more persistent. Clearer colder weather will follow overnight with scattered heavy showers.
3) Tomorrow will be a cool, blustery day with sunshine and scattered heavy showers.
I've discussed about hurricane in a easy way. Everything this realted to hurricanes is discussed in slide slide. For the students of "disaster management" i would suggest this slide. Check out this slide.
Tropical cyclones, also known as hurricanes or typhoons, regularly threaten many South Pacific countries. These powerful storms form over warm ocean waters between December and May as the Intertropical Convergence Zone moves southward with the sun. Warm, moist air rises and causes low air pressure, drawing in surrounding winds that begin to rotate due to the Coriolis effect. Further evaporation and the release of latent heat strengthen the storm into a tropical cyclone. Cyclones can produce devastating winds over 155 mph, large storm surges over 6 meters, and heavy rainfall that cause extensive damage to infrastructure, agriculture, and loss of human life. Countries like Fiji, Tonga, and Vanuatu are especially at risk
Tornadoes and hurricanes are powerful storms that form from specific weather conditions. Tornadoes are rotating columns of air that extend from thunderstorms to the ground, with wind speeds up to 300 mph. They form when warm and cold air masses meet and create instability. Hurricanes are large storms up to 600 miles wide with strong inward spiraling winds between 75-200 mph that gather heat from warm ocean waters and can cause damage when making landfall. Both storms can be predicted to some degree with watches and warnings issued ahead of their arrival to provide time to take shelter.
Fire Weather Planning Forecast Issued At 548 AM EDT THU APR 30 2015dallasbusinessnews
This document provides a fire weather planning forecast for Upper Michigan for July 28, 2015. It summarizes hot and dry conditions expected for most of the area today, with scattered showers and thunderstorms possible tonight as a cold front moves through. Gusty winds are expected on Wednesday behind the front before drier conditions return for the rest of the week. Specific forecasts are given for various zones in Upper Michigan.
The Storm Prediction Center has issued a tornado watch for portions of southeast Iowa, western Illinois, and eastern Missouri until 10:00 PM CDT. Thunderstorms are expected to develop in the afternoon over southern Iowa and northern Missouri and track southward, capable of producing large hail, a few tornadoes, and isolated damaging wind gusts up to 70 mph due to favorable wind fields for supercell storms. People in the watch area should be on the lookout for threatening weather conditions and listen for later statements or possible warnings.
National Safe Boating Week is being observed through May 22nd to promote safe boating practices. The National Weather Service is partnering with the National Safe Boating Council to send messages about wearing life jackets and safe navigation during the week. Each day will feature a public service announcement about a different boating safety topic that can be heard on NOAA Weather Radio or downloaded as an audio or video file.
This document promotes National Safe Boating Week from May 16th to May 22nd. The National Weather Service and National Safe Boating Council are partnering to raise awareness about safe boating practices through public service announcements on weather radio. Each day of the week focuses on a different boating safety topic, and links are provided to audio and video clips about life jackets, boating under the influence, marine forecasts, fire extinguishers, and more.
Fire Weather Planning Forecast Issued At 548 AM EDT THU APR 30 2015dallasbusinessnews
This document provides a fire weather planning forecast for Upper Michigan with weather conditions and forecasts for various zones in the region. Warm and moist conditions are expected to increase through Thursday bringing chances of showers and thunderstorms to the area from Thursday afternoon through Friday morning. Cooler and drier weather is then expected for the weekend.
There are no active watches, warnings or advisories
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1. Footer
FZHW52 PHFO
SRFHFO
SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN MAY 3 2015
OAHU-
400 AM HST SUN MAY 3 2015
Surf along east facing shores will be 3 to 5 feet today, lowering to 2 to 4 feet Monday.
Surf along north facing shores will be 1 to 3 feet through Monday.
Surf along west facing shores will be 1 to 3 feet through Monday.
Surf along south facing shores will be 1 to 3 feet through Monday.
Outlook through Saturday May 9: the rough east-shore surf will continue into next week as the trade
winds remain fresh to locally strong. A moderate long-period southerly swell will begin to fill in
through the day Tuesday, peak sometime Wednesday near advisory levels, then gradually subside
through the remainder of the week. A short period north swell may bring the surf up along north
facing shores Tuesday and Wednesday. A moderate northwest swell is expected to arrive late
Wednesday night into Thursday and continue into the weekend.
Surf heights are forecast heights of the face or front of waves. The surf forecast is based on the
significant wave height, the average height of the one third largest waves, in the zone of maximum
refraction. Some waves may be more than twice as high as the significant wave height. Expect to
encounter rip currents in or near any surf zone.
FXHW52 PHFO
SRDHFO
COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU
NWS/NCDDC HONOLULU HI
300 PM HST FRI MAY 1 2015
This collaborative forecast will be updated Monday through Friday at 300 pm when Pat Caldwell is
8. OPEN OCEAN SWELL HEIGHT MEASURED FROM TROUGH TO CREST IN FEET LOCATED 20
NAUTICAL MILES OFFSHORE
DMNT DIR
DOMINANT DIRECTION TYPICALLY +/-10 DEGREES IN 16 COMPASS POINTS
DMNT PD
DOMINANT PERIOD IN SECONDS
H1/3
SIGNIFICANT WAVE HEIGHT IN THE SURF ZONE
H1/10
AVERAGE HEIGHT OF THE HIGHEST ONE-TENTH WAVES IN THE SURF ZONE
HGT TEND
HEIGHT TENDENCY OF SWELL (VALID VALUES: UP/DOWN/SAME)
PROB
PROBABILITY OF OCCURRENCE (VALID VALUES: HIGH/MED/LOW)
WIND SPD
OPEN WATER WIND SPEED MEASURED IN KNOTS LOCATED 20 NAUTICAL MILES OFFSHORE
WIND DIR
WIND DIRECTION IN 16 COMPASS POINTS
SPD TEND
WIND SPEED TENDENCY (VALID VALUES: UP/DOWN/SAME)
Compass Swell Shadow Lines for Hawaii
SURF HEIGHTS WILL VARY BETWEEN DIFFERENT BEACHES AND AT THE SAME
BEACH AT DIFFERENT BREAK AREAS.
DISCUSSION:
9. Summary: spring pattern with mix of swell from north, east, and south.
Detailed: mid Friday on northern shores has small breakers for locations exposed to refracting
easterly windswell. More of the same is likely for Saturday.
A zonal jet stream at a northerly track near the Aleutians has kept surf sources to a minimum from
NW to N locally since 4/30, and should remain near nil 5/1-4. The jet track is shifting southward 5/1,
increasing odds for may-caliber surf next week.
A low pressure cell is deepening north of Hawaii near 50°N on 5/1. It is modelled to aim gales SE of
Hawaii as it moves east of the Hawaii swell window into the gulf of Alaska 5/2. A small episode is
expected on Tuesday from 350-010 degrees near the may average, which is 6 feet peak face for set
waves, or the h1/10, at top spots. This typical may event should be short-lived.
Mid Friday on eastern shores has surf out of 60-90 degrees above the trade windswell average. A
slow downward trend is expected Saturday.
Strong surface high pressure NNE of Hawaii 4/28-4/30 set up a long, wide fetch of fresh to strong
breezes over Oahu and out to the E to NE over 1000 nm. The late Thursday ascat satellite late
Thursday still showed large pockets of strong breezes aimed at Oahu within 800 nm. This should
keep the dominant wave period of the windswell on the long end of the spectrum through the
weekend, which in turn should keep breakers above average.
The surface high NNE of Hawaii 5/1 is weakening as upper level ridge north of the islands breaks
down and gives way to weak upper level troughs, associated with the southerly shift of the primary
jet over the central north Pacific. The morning ascat readings 5/1 show mostly fresh breezes ENE of
Hawaii out 800 nm. This quasi-minimum to the upstream source should coincide with surf dropping
to near the trade windswell average by late Sunday, holding about the same Monday, as the 8-10
second wave period band loses energy.
10. Models show the surface high nosing back towards the islands and increasing in strength on
Monday, then holding into Wednesday. It is not expected to be nearly as strong as the local event of
4/28-30, which kicked dominant wave periods up within 8-11 seconds, though at least back to fresh
speeds. This should trend the surf up Monday into Tuesday from 60-90 degrees, holding into mid
week with dominant periods of 7-8 seconds.
Mid Friday on southern shores has greatest size for locations receiving easterly windswell. There is
a mix of southern hemisphere low swell energy from within 150-220 degrees and 10-17 second
periods. The windswell should hold on Saturday, with SE exposures topping the heights as a long-
period SSE event fills in.
A huge, severe gale to hurricane-force low pressure cell tracked SW to S of Easter Island 4/24-27,
aiming highest seas at the Americas. Angular spreading could bring in low swell locally starting
Saturday 5/2 from 160-180 degrees. It should be long-lived.
Greater odds for surf from the common southerly swell region SE to E of New Zealand starting
locally Tuesday 5/5. A pattern similar to 4/13-17, which gave the above average SSW surf locally
4/21-23, occurred starting 4/29 just SE of New Zealand. The low center deepened to 964 mb on 4/29
as a cold front backed by gales to storm-force winds pushed NE to near 40s, or about 3800 nm away.
Seas grew over 30 feet into 4/30. The pattern is shifting east 5/1.
The new episode is expected to reach the pacioos/cdip american samoa buoy on Saturday. The long-
period forerunners are due locally on Tuesday 5/5. The onset day for remote events are usually
extra-inconsistent on the sets. The event should slowly build Tuesday, reaching above average by
Wednesday from 185-200 degrees.
11. Into the long range, the jet stream pattern 4/30-5/1 shows a meridional pattern E of New Zealand,
with a large, wide equatorward loop. A pair of short-waves is modelled to fill into the long wave
pattern from the SW. Each has an enhanced surface low pressure area, and in turn, new regions of
gales to storm-force winds. The first in the follow-up series is SE of New Zealand on 5/1. The second
is due 5/3. Both are aiming seas parallel to the Hawaii swell window, primarily to the east of Hawaii.
This makes for larger error bars for the local maximums. The net result should be overlapping
events keeping surf average to above average 5/5-12 from within 180-200 degrees, with local
maximums roughly 5/6, 5/8, and 5/10.
In the northern hemisphere, a cut-off jet level low is modelled near the dateline near 45°N 5/3-5,
with a marginal gale surface low. It is predicted to remain stationary 5/4 then slowly move east just
south of the Aleutians 5/6-7. It should bring surf above the may average starting locally Thursday
5/7, lasting into the weekend of 5/9 from 330-360 degrees.
Trades should remain near the fresh mark 5/7-9 with surf at average to above average levels from
60-90 degrees. A short-lived minimum to the trades within moderate to fresh speeds is predicted for
late Wednesday to early Thursday 5/6-7, associated with the eastward track of the Aleutian low over
the longitude of Hawaii north of 40°N.
Long range forecasts are subject to low confidence.
This collaborative forecast will resume on Monday, May 4.
This forecast was produced through the collaborative efforts of NWS and NCDDC. Please send
suggestions to w-hfo.webmaster@noaa.gov or call the Warning Coordination Meteorologist at 808-
973-5275.
Additional resources: see /in lowercase/ http://www.prh.noaa.gov/hnl/pages/marine.php.
NWS Forecaster and Pat Caldwell, Pacific/Hawaii Liaison Office, NCDDC
Additional Resources:
Latest North Pacific Surface Analysis
Upcoming tides for select Hawaii locations
Tides for Honolulu
Tide tables for Hawaii
http://www.prh.noaa.gov/hnl/pages/SRF.php#Footer