Hurricane Irma. Hurricane Warning for Puerto Rico

Our home base in northeastern Fajardo, Puerto Rico

We are safe in our RV in Colorado.  Our boat is insured.  When we left the boat in storage in June, it was prepped for a hurricane.  We monitor the Caribbean weather daily.  We’ve been watching Irma since it was in the mid-Atlantic.  We've experienced a low-wind Tropical Storm & 70 kts at anchor, but this is our first time in the path of a hurricane.

Dry boat storage at Puerto del Rey

Irma's track has been adjusted south this morning and Puerto Rico has officially activated emergency hurricane plans.  We are officially freakin worried about our home island, that floods when it rains...

“...IRMA BECOMES AN EXTREMELY DANGEROUS 

CAT 5 HURRICANE...

MAXIMUM SUSTAINED WINDS...175 MPH...280 KM/H…

Hurricane-force winds extend outward 

up to 45 miles (75 km) from the center 

and tropical-storm-force winds extend outward 

up to 140 miles

(220 km)…”

NOAA wind forecast

Our hurricane plan:  s/v Odin is in dry storage at Puerto del Rey, Fajardo, Puerto Rico.  She's stripped and strapped down.  We chose Puerto del Rey because it is largely considered one of the safest storage yards in the Caribbean and is approved by our insurance company.

“Puerto Del Rey Marina provides excellent 

protection from hurricanes for 

mono-hull and catamarans. 

Underground hurricane-proof steel and 

cement structures are protected from the sea 

by 100,000 square meters of US NAVY 

controlled mangrove. A block-and-jack-stand 

support system is used within a 

network of strong tie-down points.”

Our location in the yard, back row next to a large powerboat

Hurricane monitoring:  We receive Chris Parker & NOAA weather forecast emails daily.  When there is a threat, we monitor the NOAA Tropical Storm Forecast every 6 hours.  There are several other websites that we follow also.

Officially the strongest hurricane in the Atlantic Basin

Hurricane Hugo:  Hurricane Hugo is the most talked about weather event in Puerto Rico.  It was part of the criteria when we chose our storage facility.  It was a Cat 5 approaching the islands, Cat 4 over St. Croix and a Cat 3 when it reached Puerto Rico (Cat 4 damage recorded on the ground).  You can read more here:

https://www.nap.edu/read/1993/chapter/2#3

Sailors may remember that Hurricane Hugo is the storm that took Fatty Goodlander's boat Carlotta, while anchored in Culebra, Puerto Rico.  You can read an excerpt here:

http://www.fattygoodlander.com/corina__other_boats/carlottas_end

Latest Chris Parker forecast:  N PR near SanJuan: ENE<NE@7-15<15-20k Today; then NE<N@15-20g25k overnight-Wed6 morning N@15-30<W@50-70k<SW@40-70k Seas 25-35’ Storm Surge 6-10’ Wed6 afternoon-Wed6 midnight; SW<S@40-70<S@30k Late Wed6 night-Thu7 morning then similar to Guadeloupe-Leewards Thu7 onward.  

Webcams:

Puerto del Rey:  http://www.puertodelrey.com/en/boatyard-storage

Fajardo:  https://www.webcams.travel/webcam/1277812058-Weather-Fajardo-Bay-View-from-Rabirubia-Vacation-Rental-Playa-Sardinera

Links:

Chris Parker

NOAA Hurricane:  http://www.nhc.noaa.gov/

Puerto del Rey:  http://www.puertodelrey.com/en/boatyard-storage

Tuesday morning forecast, NOAA Hurricane Center, Public Advisory: (http://www.nhc.noaa.gov/text/refresh/MIATCPAT1+shtml/051742.shtml?)

000

WTNT31 KNHC 051159

TCPAT1

Hurricane Irma Special Advisory Number  25

NWS National Hurricane Center Miami FL       AL112017

800 AM AST Tue Sep 05 2017

...IRMA BECOMES AN EXTREMELY DANGEROUS CATEGORY 5 HURRICANE...

...PREPARATIONS SHOULD BE RUSHED TO COMPLETION IN THE HURRICANE

WARNING AREA...

SUMMARY OF 800 AM AST...1200 UTC...INFORMATION

----------------------------------------------

LOCATION...16.7N 57.7W

ABOUT 270 MI...440 KM E OF ANTIGUA

ABOUT 280 MI...445 KM ESE OF BARBUDA

MAXIMUM SUSTAINED WINDS...175 MPH...280 KM/H

PRESENT MOVEMENT...W OR 280 DEGREES AT 14 MPH...22 KM/H

MINIMUM CENTRAL PRESSURE...929 MB...27.44 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY:

The government of the Dominican Republic has issued a Hurricane

Watch from Cabo Engano to the northern border with Haiti and a

Tropical Storm Watch from south of Cabo Engao to Isla Saona.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Warning is in effect for...

* Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, and Nevis

* Saba, St. Eustatius, and Sint Maarten

* Saint Martin and Saint Barthelemy

* British Virgin Islands

* U.S. Virgin Islands

* Puerto Rico, Vieques, and Culebra

A Hurricane Watch is in effect for...

* Guadeloupe

* Dominican Republic from Cabo Engano to the northern border with

Haiti

A Tropical Storm Warning is in effect for...

* Guadeloupe

* Dominica

A Tropical Storm Watch is in effect for...

* Dominican Republic from south of Cabo Engao to Isla Saona

A Hurricane Warning means that hurricane conditions are expected

somewhere within the warning area. A warning is typically issued

36 hours before the anticipated first occurrence of tropical-storm-

force winds, conditions that make outside preparations difficult or

dangerous. In this case, for some of easternmost islands, the

hurricane conditions are expected within the next 24 hours.

Preparations to protect life and property should be rushed to

completion.

A Tropical Storm Warning means that tropical storm conditions are

expected somewhere within the warning area in this case within 36

hours.

A Tropical Storm Watch means that tropical storm conditions are

possible within the watch area, generally within 48 hours.

Interests elsewhere in the Dominican Republic, along with Haiti,

the Turks and Caicos Islands, Cuba, and the southeastern and central

Bahamas should monitor the progress of Irma.

For storm information specific to your area in the United

States, including possible inland watches and warnings, please

monitor products issued by your local National Weather Service

forecast office. For storm information specific to your area outside

the United States, please monitor products issued by your national

meteorological service.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

At 800 AM AST (1200 UTC), the distinct eye center of Hurricane Irma

was located near latitude 16.7 North, longitude 57.7 West. Irma is

moving toward the west near 14 mph (22 km/h), and this general

motion is expected to continue today, followed by a turn toward the

west-northwest tonight. On the forecast track, the dangerous core of

Irma will move near or over portions of the northern Leeward Islands

tonight and early Wednesday.

Reports from NOAA and U.S. Air Force Hurricane Hunter aircraft

indicate Irma continues to strengthen and maximum sustained winds

have increased to near 175 mph (280 km/h) with higher gusts.  Irma

is an extremely dangerous category 5 hurricane on the Saffir-Simpson

Hurricane Wind Scale.  Some fluctuations in intensity are likely

during the next day or two, but Irma is forecast to remain a

powerful category 4 or 5 hurricane during the next couple of days.

Hurricane-force winds extend outward up to 45 miles (75 km) from the

center and tropical-storm-force winds extend outward up to 140 miles

(220 km).

The latest estimated minimum central pressure from aircraft data is

929 mb (27.44 inches).

HAZARDS AFFECTING LAND

----------------------

STORM SURGE:  The combination of a dangerous storm surge and large

breaking waves will raise water levels by as much as 7 to 11 feet

above normal tide levels along the coasts of the extreme northern

Leeward Islands within the hurricane warning area near and to the

north of the center of Irma.  Near the coast, the surge will be

accompanied by large and destructive waves.

The combination of a dangerous storm surge and the tide will cause

normally dry areas near the coast to be flooded by rising waters

moving inland from the shoreline.  The water is expected to reach

the following heights above ground if the peak surge occurs at the

time of high tide...

British and U.S. Virgin Islands except St. Croix...7 to 11 ft

Northern coast of Puerto Rico...2 to 4 ft

Southern coast of Puerto Rico and St. Croix...1 to 2 ft

The deepest water will occur along the immediate coast in areas of

onshore winds, where the surge will be accompanied by large and

destructive waves.  Surge-related flooding depends on the relative

timing of the surge and the tidal cycle, and can vary greatly over

short distances.  For information specific to your area, please see

products issued by your local National Weather Service forecast

office.

WIND:  Hurricane conditions are expected within the hurricane

warning area in the Leeward Islands by tonight, with tropical storm

conditions beginning later today. Tropical storm conditions are

expected within the tropical storm warning area where hurricane

conditions are also possible. Hurricane conditions are expected

to begin within the hurricane warning area in the British and U.S.

Virgin Islands and Puerto Rico on Wednesday, with tropical storm

conditions beginning tonight. Hurricane and tropical storm

conditions are possible within the watch area in the Dominican

Republic by early Thursday.

RAINFALL:  Irma is expected to produce total rainfall accumulations

of 4 to 8 inches with isolated maximum amounts of 12 inches across

the northern Leeward Islands, the British and U.S. Virgin Islands,

and Puerto Rico.  These rainfall amounts may cause life-threatening

flash floods and mudslides.

SURF:  Swells generated by Irma will affect the northern Leeward

Islands, Puerto Rico, and the U.S. and British Virgin Islands

during the next several days.  These swells are likely to cause

life-threatening surf and rip current conditions. Please consult

products from your local weather office.

The BVI's are just SWELL!

St. John, USVI & part of the BVI's

As we cruise back through the Virgin Islands this season, our goal is to visit anchorages we skipped last time.  When we could find all around protection last year, we took it.  This season, I'm hoping to be more adventurous.  New friends are sharing their favorite spots and I'm keeping a list.  However, in passing, someone mentioned, "We got caught in an anchorage with a ground swell and had to move in the middle of the night."  How do we avoid that?!

So, I looked it up.  According to the Scott's "Cruising Guide to the Virgin Islands" (the bible for this area), certain anchorages should be avoided when the "ground sea is running."  One example is Trunk Bay, St. John.  OK, what is it and where is that forecast?

In the same book in the Virgin Weather section, they refer to ground swells.  The same thing?  Confusing.  "During the winter months of November through April, any significant weather in the North Atlantic will product heavy swells along the entire north coast of the Virgins several days later.  These ground swells have little effect on vessels under sail, but can turn a normally tranquil anchorage into pounding surf.  Most anchorages exposed to the north are prone to this phenomenon--chose your anchorage accordingly."  Hmmmm.  More information please.

NOAA Swell forecast

On our visit to the BVI's last year, friends warned us off of Cane Garden Bay and the north side of St. John during a "North swell".  (Yep, the cruising guide confirms Cinnamon Bay is "untenable during northeast ground seas")!  This led us to subscribe to the NOAA Wave Period/Swell Direction Forecast (or read all the way to the end of the Chris Parker forecast).  North swell is also briefly discussed in Bruce Van Sant's weather section regarding the north coast of the Dominican Republic.

Further googling swell in the Virgin Island area revealed the terms "Atlantic swell" or references to "No swell".  (Isn't there is always an ocean swell ie. Statia?!  Apparently it means "No north swell").

All good wave research ultimately lands me on surfing websites.  Who LOVES big waves?  Surfers!  And their wave forecasting is impressive.  Apparently the north coast of Dominican Republic, Puerto Rico and the Virgin Islands are popular surf spots in the winter because of THE NORTH SWELL!  Some info I found about "groundswell" (one word) from leading surfing meteorologist and Surfline.com forecaster Sean Collins about the difference between normal wind swell and groundswell (http://www.surfline.com/community/whoknows/whoknows.cfm?id=1144):

"Windswells are swells that are generated by local winds within a few hundred miles of the coast. As a result, the swell periods are short (four to 10 seconds between crests) and the waves tend to stack up on each other with very consistent sets. Also, a windswell's energy doesn't extend very deep -- maybe only 100 feet or so -- so it can only travel a few hundred miles before dissipating because most of the wave energy is concentrated closer to the ocean surface. 

Groundswells are swells that are usually generated by winds much farther away. These swells are created by strong winds over long distances -- we refer to this distance as the "fetch" -- and over longer periods of time. As a result, more energy is transferred into the water during the generation of the waves, which create longer swell periods. Waves with longer swell periods can travel great distances without losing the swell energy like windswells do. Furthermore, swell energy in groundswells can also extend down to around 1,000 feet deep. This allows greater interaction with the ocean floor when the groundswells move into shallow water. For example, this process of refraction will allow groundswells to wrap into a spot -- up to 180 degrees or more -- while windswells wrap very little if at all."  And this is why the ground seas running or north swell is so dangerous for sailors.

Van Sant, Passages South

Summary:  Take any groundswell/ground seas/north well SERIOUSLY.  It's not just "windy and rolly".  We sat out the last north swell tucked into Ensenada Honda, Culebra, Puerto Rico.  

My final definition:  Any significant low pressure system in the North Atlantic can create an ocean swell thousands of miles ahead of it.  The strong winds over long distances (fetch) creates longer period swells of 10-20 sec+ period.  These waves have more energy than a normal wind driven wave, extending down to 1000 ft deep.  This can make unprotected northern anchorages in the Virgins not just rolly but "untenable" (unable to be occupied--calculating the scope required is precarious and picturing what it is doing to your anchor should also keep you up all night).  It will produce strong rip currents ("no swimming" warning from the BVI during the last "Northerly"), and landing dinghies can be dangerous (ie. The Baths, Virgin Gorda).  The swell may last for 3-4 days.  And don't forget:  swell may arrive the 1-2 days before the forecast wind shift!  The waves travel ahead of the weather system!

NOAA Offshore Forecast

On a side note:  This relates back to a discussion about waves and swell in my previous weather blog (what-do-you-use-for-weather). Here is how a north swell can affect your forecast. Van Sant recommends always using the NOAA Offshore Report, but this season I've discovered the NOAA Coastal Water Report puts the "wind" wave and "swell" wave forecast next to each other, so it's easier to recognize a confused sea state.   If you compare the swell to the normal wave forecast, you can more easily predict "washing machine" seas.  Not comfortable, and slows us down.  Example:  EAST WINDS 10 TO 15 KNOTS. SEAS 4 TO 6 FEET WITH OCCASIONAL SEAS UP TO 8 FEET. DOMINANT PERIOD 10 SECONDS. NORTH SWELL 4 TO 5 FEET. 

NOAA Coastal Waters Forecast

References:

Passages South by Bruce Van Sant

Scott's Cruising Guide to the Virgin Islands

Nigel Calder's Cruising Handbook

surfline.com

NOAA marine forecasts

Tracking Hurricanes

Hurricane season is upon us in the Caribbean.  With internet access anywhere from good to non-existent, we need a reliable source of info about possible activity.  I've received our first Atlantic Tropical Weather Outlook email, so I'll share what I have set up, then I'll update as the season progresses.

This is based on an article from The Boat Galley written in 2006, titled Tropical-Storm-Tracking-with-Sailmail-Revised-2-06.  I've tweaked it with updated info and to include references to our Iridum GO! (see blog, "Setting up my Iridium GO!")  The goal it to use Saildocs to receive text forecasts on our Iridium email (and regular email when available).  Secondly, research and bookmark links for low-bandwidth graphic forecasts for the Opera Mini browser (see blog "Slow internet and/or using less data") when closer tracking is required.

We'll start simple.  On Twitter, follow @NHC_Atlantic:  on the Iridium GO!, text to 40404: follow @NHC_Atlantic

Facebook also has several good pages including : NOAA NWS National Hurricane Center, Mike's Weather Page, Marv's Weather Service, and Crown Weather Service

Now it's time to go to saildocs.com and get familiar with their service.  The following are the send/sub requests you might need for hurricane season.

TEXT FORECASTS, Saildocs, (Atlantic):  

If you want to check my work, for current Saildocs filenames send email to query@saildocs.com:

• send nws-gmex

I recommend the Offshore Forecast throughout the season (text):

• sub FZNT23.KNHC (see blog What do you use for weather?)

but if you’re sitting for hurricane season, maybe:

• Synopsis only (Carib):  send/sub AMZ001
• Windward/Trinidad only (no synopsis!): send/sub AMZ035

The following 11 subscriptions are for tracking a tropical storm.  After the initial subscription, you only get an email when there is a change:

1.  Atlantic/Carib Tropical Wx Outlook: 

• sub atl.outlook interval=1 days=365  

2.  Atlantic/Carib Discussion (gen comments/prediction confidence).  NHC monitors multiple systems so repeat for 2, 3, 4, & 5.

• sub atl.disc1 interval=1 days=365
• sub atl.disc2 interval=1 days=365
• sub atl.disc3 interval=1 days=365
• sub atl.disc4 interval=1 days=365
• sub atl.disc5 interval=1 days=365

3.  Tropical Depression Forecast/Advisory (detailed).  NHC monitors multiple systems so repeat for 2, 3, 4, & 5.

• sub atl.tech_advis1 interval=1 days=365 
• sub atl.tech_advis2 interval=1 days=365 
• sub atl.tech_advis3 interval=1 days=365 
• sub atl.tech_advis4 interval=1 days=365 
• sub atl.tech_advis5 interval=1 days=365

(Check at 1 hour intervals for updates:  interval=1)(Specify subscription period: days=365)

You can also get National Hurricane Center's High Seas Forecast (text):

• send/sub FZNT02.KNHC

I recommend subscribing to the text forecasts above.  However, the following are larger graphic forecasts, so experiment then have this list standing by for when things require closer observation:

Bookmark NHC Marine Forecasts in Opera browser:  http://www.nhc.noaa.gov/marine/

Here are the 5 primary graphics from the National Hurricane Center:
GRAPHICS, Saildocs, (Atlantic).  Be aware of file size vs your data plan

• (To get a list of Radiofax Internet File Names (Caribbean/New Orleans):  http://weather.noaa.gov/pub/fax/rfaxmex.txt )

• 1.  NHC Sea State Analysis (graphic, current):  send PJEA11.TIF

Subscribe 0000Z (graphic): sub PJEA88.TIF

Subscribe 1200Z (graphic): sub PJEA90TIF

• 2.  NHC Tropical Surface Forecast (graphic, E half, 24, current): send PYEE10.TIF

24 HR 0000Z: sub PYEE79.TIF

24 HR 1200Z: sub PYEE80.TIF

Get 48 (graphic, E half, current): send PYEI10.TIF

48 HR 0000Z: sub PYEI81.TIF

48 HR 1200Z: sub PYEI82.TIF

Get 72 (graphic, E half, current): send PYEK10.TIF

72 HR 0000Z: sub PYEK83.TIF

72 HR 1200Z: sub PYEK84.TIF

• 3.  NHC Wind/Wave forecast (graphic, current, 24): send PWEE11.TIF

0000Z: sub PWEE89.TIF

1200Z: sub PWEE91.TIF

Get 36 HR, 1200Z:  send/sub PWED98.TIF

Get 48 (graphic, current): sub PWEI11.TIF

0000Z:  sub PWEI88.TIF

1200Z:  sub PWEI89.TIF

Get 72 (graphic, current): sub PJEK11.TIF

0000Z:  sub PJEK88.TIF

1200Z:  sub PJEK89.TIF

• 4.  NHC Wave Period/Swell Direction (graphic, 48 HR, current):  send PJEI11.TIF

0000Z: sub PJEI88.TIF

1200Z: sub PJEI89.TIF

Get 72 HR (graphic, 0000Z):  send/sub PKEK88.TIF

• 5.  NHC Tropical Cyclone Danger Area (graphic, current, after May 15/High Wind Sea):  send PWEK11.TIF  

0300Z:  sub PWEK89.TIF

0900Z:  sub PWEK90.TIF

1500Z:  sub PWEK91.TIF

2100Z:  sub PWEK88.TIF

(Mariner’s 1-2-3 Rule)

I also consider the following useful:

• Tropical Surface Analysis (low res wide area, graphic, E half, current):  send PYEA11.TIF

(W half, current):  send PYEB11.TIF

0000Z (E): sub PYEA86.TIF (W) sub PYEB86.TIF

0600Z (E): sub PYEA87.TIF (W) sub PYEB87.TIF

1200Z (E): sub PYEA85.TIF (W) sub PYEB85.TIF

1800Z (E): sub PYEA88.TIF (W) sub PYEB88.TIF

Is that clear as mud?  I had to save to the blog, so I wouldn't risk losing all my notes!  I can't promise this is all accurate, but it's a start.  Please share any ideas (or point out any errors) below.  Good luck out there.

"What do you use for weather?" (Update: Ocean Swell & NHC)

This should really be called "The Weather Cycle."
http://www.srh.noaa.gov/jetstream/atmos/images/hydro.jpg

NERD ALERT!  This blog isn't for everyone.  I'll update as our offshore weather knowledge evolves.

We thought, as pilots, we'd have an advantage in this department and maybe we do, but offshore weather is different. You are not only concerned about wind direction and speed (and thunderstorms or "squalls") but wave direction, height and period. Our previous weather sources weren't cutting it on the Chesapeake. One thing for sure is most good weather info is free!  NOAA & the NWS are government-funded and, as it turns out, will carry you pretty far down the Caribbean. It's always a good idea to consult at least two sources of info.  You'll learn which one is more accurate in your area.  Here's what we are currently using:

PocketGrib app, map view

PocketGrib app, Meteogram view

GRIB: NOAA automated, computer-generated forecast usually GFS but also WW3, US Navy, or Euro, for example.  I'm not going to explain all of that here, but know what you are looking at.  Different GRIB viewers have different default settings. You also need to know a human does not review this information.  You need to use your noggin (or pay Chris Parker see below).  Our preferred GRIB viewer is the app, PocketGrib (Not user-friendly, so you may need to find a fellow sailor. Thanks Deb Akey, for the tutorial).  Again, GRIB's are free information, so do your research before paying for this info or a viewer!

Windfinder app

WindFinder app: This is the third most common source of weather info we hear about from other cruisers (Chris Parker is second to GRIB). We paid for the pro-version to get Euro & the extended forecast (also uses less data since there are no ads). A cool trick you can do is watch conditions at the ports before you, ie. if you're in Georgetown, watch Staniel Cay for the wind shift.  In St. Louis, we would watch Jefferson City or Columbia.)  UPDATE:  Unfortunately, this seems to underestimate the winds on the south coast of Puerto Rico.

NOAA Marine Forecast

NWS NOAA Offshore Report by Tropical Prediction Center in Miami:  I believe the SSB broadcast has been cancelled, but you can get this on the internet (nws.noaa.gov) or by email ie. Iridium (see SailDocs). We get the Tropical N Atlantic & Caribbean Sea.  Don't let the clunky, government website deter you--there is some good stuff here (check out the tide tables while you're browsing:  Blog "When is high tide in Georgetown?", http://tidesandcurrents.noaa.gov/tide_predictions.html).  This report is a little daunting to read. It used to make my eyes glaze over, not unlike an electrical schematic.  First, figure out which area you need (see outline below) or start with "condensed for radio broadcast" until you get the hang of it.  It's very general (broad time frames over a large area) but like the GRIB, it is part of the source info used by Chris Parker and other paid sources. 

• Report Name (FZNT23.KNHC, you'll need this for SailDocs)
• Check the time to see how old the report is (1114 AM EDT SUN MAR 27 2016)
• "SEAS GIVEN AS SIGNIFICANT WAVE HEIGHT...WHICH IS THE AVERAGE HEIGHT OF THE HIGHEST 1/3 OF THE WAVES. INDIVIDUAL WAVES MAY BE MORE THAN TWICE THE SIGNIFICANT WAVE HEIGHT!"
• Synopsis

(For a reference lat/long map, try Bahamas Explorer Chartbook weather page or  http://www.nws.noaa.gov/os/hurricane/resources/HurricaneTrackingMap11-14.pdf)

AMZ011:  N of 18N, W of 85W (including yucatan basin)

AMZ013:  N of 18N, 76W-85W (including cayman basin)

AMZ015:  Caribbean approaches to the windward passage

AMZ017:  Gulf of Honduras

AMZ019:  15N-18N, 80W-85W

AMZ021:  15N-18N, 72W-80W

AMZ023:  N of 15N, 64W-72W (DR, PR, Virgins)

AMZ025:  Offshore waters Leeward Islands (Lesser Antilles, St. Martin-Dominica)

AMZ027:  15N-19N, 55W-60W

AMZ029:  11N-15N, W of 80 W 

AMZ031:  11N-15N, 72W-80W (including Colombia basin)

AMZ033:  S of 15N, 64W-72W (including Venezuela basin)

AMZ035:  Offshore waters windward islands (Martinique through Grenada) including Trinidad & Tobago

AMZ037:  Tropical n atlantic from 07n to 15n between 55w and 60w

AMZ039:  SW caribbean S of 11N (including approaches to Panama Canal)

AMZ101:  Synopsis for the SW N atlantic including the bahamas

AMZ111:  Atlantic from 27N to 31N w of 77W

AMZ113:  Atlantic from 27N to 31N between 70W and 77W

AMZ115:  Atlantic from 27N to 31N between 65W and 70W

AMZ117:  Bahamas including Cay Sal bank

AMZ119:  Atlantic from 22N to 27N (E of Bahamas) to 70W 

AMZ121:  Atlantic from 22N to 27N between 65W and 70W

AMZ123:  Atlantic S of 22N W of 70W (including approaches to the Windward Passage)

AMZ125:  Atlantic S of 22N between 65W and 70W (including Puerto Rico Trench)

AMZ127:  Atlantic from 19N to 22N between 55W and 65W

If you fell asleep in the the middle of the Offshore Report, WAKE UP!

Buoys:  Another original source of weather info is buoys. You can got to NOAA Data Buoy Center or download apps to see live information, particularly helpful while we were in the Chesapeake. (They always seemed to be out of service when we really needed them). Good for a day sail when you have cellular. 

Chris Parker:  The Marine Weather Center (mwxc.com). Chris is a meteorologist who specializes in marine Caribbean forecasts. He is good at interpreting and explaining the big picture and trends. He also combines a lot of the above information into a more readable format.  You will learn about weather patterns, so you can also track them on other sources (above) when out of range. Read his FAQ including philosophy (he gives "worst case" which is good, but don't let it scare you from ever leaving port) & "How to read email forecasts".  Make a copy of the Explorer Chart Weather Plotting chart and copy down an outline of the email/broadcast so you don't get overwhelmed.

If you have SSB, you can listen to his broadcasts for free, if you know the time and frequency (check with other cruisers in the area or link frequency list). His broadcasts tend to be more detailed and up-to-date (sometimes better if your eyes gloss over while reading the email, but my wanders during the long broadcast--try having a printed format in front of you to help follow along. See below). 

We receive his email forecasts: We can get a copy on the Iridium when wifi isn't available. We like having a printed copy to study. We get it the night before.  We can discuss without missing any of the broadcast. It also gives us access to his online simulcast & recordings. 

SailDocs.com:  We use this free resource to get NOAA weather on the Iridium GO!  Practice before you need it!  Go to saildocs.com for more information.  I found their email instructions tedious.  Our friends on Kelly Nicole helped me set this up.  Caution:  Delete your “signature” or “email-footer” or Saildocs may not respond.  It may be best to copy & paste the request.  SailDocs is very picky about capital letters, punctuation and spacing.

• OffShore Report: To receive the full SW & Tropical North Atlantic & Caribbean Sea, send an email to query@saildocs.com, (subject blank), body of email:  FZNT23.KNHC  (FZNT31.KNHC for condensed).  
• To subscribe (receive once per day for 14 days): sub FZNT23.KNHC
• To receive every 6 hours:  sub FZNT23.KNHC time=00:00 interval=6
• To receive for more than 14 days: sub FZNT23.KNHC time=00:00 interval=6 days=90
• Grib (beware of data usage, no spaces—adjust lat/long for your area.  When you receive the email, it will ask how you want to open it.  Select your preferred grab viewer):  send gfs:22N,19N,72W,69W
• Request text-only web page (beware of data usage)

Local net:  It's always better to go to the source (and have a written copy to review at your leisure--another reason we like emails), but if you don't have internet or SSB, the local net will often read Chris Parker emails or WindFinder info (ask the source if they don't disclose).

Still here?  Here's some new toys we've been playing with:

Windyty.com showing "island lee" in the Mona Passage

windyty.com: This is a great graphic website if the Offshore Report makes your eyes glaze over.  The teacher in me thinks this would be a great way to teach island lee or the relationship between wind & waves.  Try playing with wind and waves in the Mona Passage.  It's a bandwidth hog, so this isn't our primary source of weather.  (I think it works better on the laptop than the iPad.)

windrea.net showing the current through the Mona Passage

windria.net:  A similar website to windyty.com, but also allows you to view current.  Helpful and educational!

Beaufort table explains how wind affects wave height

What I've learned about waves:
Waves are complicated.  They are mostly caused by the the wind.  The Beaufort table above explains the wave heights you should expect based on wind strength.
The depth of water also affects waves.  A shallower body of water can be "choppier" with shorter period waves, ie. Chesapeake Bay and Bahia de Samana in the Dominican Republic.
Fetch is how far a wave has travelled.  The longer the fetch, the bigger the waves, ie. any large body of water, but in particular, the Atlantic Ocean!

An NOAA article, "A closer look at wave forecasts:  http://www.vos.noaa.gov/MWL/apr_06/waves.shtmlBeaufort force Wind & wave table

After a blow, waiting 1-2 days for waves to "lay down" will give us the best ride.

What is ocean swell? Swell is a collection of waves moving away from distant weather systems.  They can travel halfway around the world!   An excellent explanation of these waves comes from surfers.  Check out stormsurf.com's "Wave Basics" for a more detailed explanation.  Being aware of a north swell is important on the north shore of the Dominican Republic, northern anchorages in the BVI and in the more exposed anchorages of the southern Caribbean. I've added the graphic "Peak wave period, primary swell direction" to our email weather list.

Saildocs.com request, email query@saildocs.com:

For 48 HR, current:  send PJEI11.TIF

Subscribe to 48 hr, 0000Z: sub PJEI88.TIF

Subscribe to 48 hr, 1200Z: sub PJEI89.TIF

Get/subscribe 72 HR, 0000Z:  send/sub PKEK88.TIF

Learn more about this graphic forecast on the National Hurricane Center's Marine Product Descriptions page:  http://www.nhc.noaa.gov/abouttafbprod.shtml#PEAKWAVE

Summary:

• Track the weather daily, so you know which of your sources is most accurate in your area and currently functional.  {cough, cough}  Saildocs.  {cough, cough}  Iridium.
• Know the source and time stamp of the data.  Don't assume.  Ask if it's not obvious.
• Use multiple sources of info.  Cross reference.
• Have a written copy--either that you transcribed, email or saved from app/website.  Take a screenshot if necessary, for when the internet is not available.  The Captain frequently refers to PocketGrib throughout the day.
• Discuss!  No one loves to talk about the weather more than cruisers.  "Hey, did you check the weather this morning?"  (Like we didn't!  Ha, ha).  "What do you think?"  "That Crazy Chris Parker!"  "THAT wasn't in the forecast!" 

Don't forget to bookmark the mobile versions of these websites:
Offshore:  http://cell.weather.gov/marine/off.htm
Bouys:  http://www.ndbc.noaa.gov/mobile/

NHC Marine Forecasts: http://www.nhc.noaa.gov/mobile/marine.php

When is high tide?

Nerd alert—The word of the day is, TIDE!  Say it with me, T-IIIII-DDD-EEEEE!

It all started with a simple question--when is high tide in Georgetown, Bahamas?  On our journey south, Mother Nature gently taught us land-locked Missourians about tides.  In Annapolis, MD the mean range was 0.97 ft with fixed docks at most of the marinas.  By the time we reached Brunswick, GA the mean range was 6.6 ft with most marinas having floating docks.  In Florida, the mean range goes back down to 2.5 ft.  In the Bahamas, it is 3 ft (mostly fixed docks).  (The largest tides in the world are 38 ft in Nova Scotia!)

Definition:

According to Chapman’s the definition of tide is “…the rise and fall, the vertical movement, of bodies of water as a result of the gravitational pulls of the moon and sun…Tides originate in the open oceans and seas, but are only noticeable and significant close to shore...Curiously, the effect of tides may be more noticeable a hundred miles up a river than it is at the river's mouth because water piles up higher in the river's narrower stretches.”  (versus current which is the horizontal flow of water.)  

The effect of the moon:  When the moon is full, it is called “Spring tides” and have a greater range.  When the moon is quarter, it is called “Neap tides” and have less range.  As we learned in Special Report: What the heck is a perigean spring tide?, "When the moon is closest to the earth, it is called a lunar perigee.  The gravitational pull of the moon is the strongest.  Three to four times a year, the lunar perigee and full moon coincide.  This is the perigean spring tide (or unofficially, the supermoon or "king tide" in New Zealand) and can affect tides up to 20 percent (usually just a few inches).  Apparently, we experienced this once in Annapolis--when it's perigean spring tide, wind blows onshore from the bay and it storms (barometric pressure drop), they get flooding downtown." (See weather below)

The effect of weather:  According to NOAA, “we cannot predict the effect that wind, rain, freshwater runoff, and other short-term meteorological events will have on the tides.”

In an example, Explorer Chart's stated, "...the tides were running at least ½-meter higher than predicted schedules—that would be 1.5 meters above chart datum—Mean Low Water Springs. This was due to the Derecho that occurred in the Exumas on January 6, 2016."  In other words, the high winds had driven more water into the Bahama Banks than usual.

Explorer Chartbook further explains tides by stating, “[it is] part science, part art…Tides are seldom exactly like the predictions.”  and further explaining that tide is affected by local features with differences at cuts.  “Generally, the farther from the ocean, the later the tide.”

The tidal flow in our part of the world is generally a 6-hour cycle between high tide and low tide and changes daily.  There are generally, two high tides and two low tides a day.

I learned the term “rage tide” from the National Park Service kayaking website, while anchored at Cape Lookout Bight just outside Beaufort, NC.  http://www.nps.gov/calo/planyourvisit/paddling.htm 

“Most paddlers will want to avoid the rage tide, the time when the current flows the hardest, as ½ of the total water volume passes through inlets during the third and fourth hours of tide flow. During this time, flatwater will turn to whitecap waves and intermediate terrain can become expert.”

This is further explained by the Rule of Twelfths:  Per Nigel Calder's Cruising Handbook, you can use the Rule of Twelfths to approximate the state of tide.  "This says that in the first hour after high or low tide, the water falls or rises by one twelfth of the total tide; in the second and fifth hours, it is two twelfths; and in the third and fourth hours, it is three twelfths."  This also means that the hour before and hour after, you are still relatively close to high/low tide.

What are tide tables:

According to Chapman’s, The National Ocean Service (NOAA) is responsible for surveying and publishing the computer-generated Tide Tables which are “…PREDICTED times and heights of high and low waters for each day of the year at a number of important points known as ‘reference stations.’”.  This information is available for free at http://tidesandcurrent.noaa.gov

More examples of tide information:

Navionics e-charts:  “Our Tide & Current data are predictions based on the government Tide & Current Stations (including many different sources, which are proprietary information)…Please note that the Tide & Current information do not take Daylight Saving Time (DST) into account, so during this time period the predictions may be off by one hour if the device settings have not been adjusted for DST.”

Garmin BlueCharts: source unknown

Explorer Charts:  pg 72 Bahamas Exumas.  Nassau tide tables, “NOTE:  this data may differ slightly from the Bahamas Dept of Meteorology tables due to different source data.”  They also give a correction range for the Bahamas of Nassau -0:13 to 0:30 (source:  Bahamas Department of Meteorology)

A Cruising Guide to:  The Southern Bahamas by Stephen Pavlidis

A Yachtsman's Guide to the Bahamas

Bahamas Department of Meteorology (bahamasweather.org.bs) daily weather forecast

bahamascruisersguide.com 

The local net (usually references local knowledge)

OR:  the book Passages South, The Thornless Path to Windward by Bruce Van Sant, "Near open ocean you can assume high tide at 8 o'clock local time on the day of a full moon.  Add 52 minutes a day thereafter and do without tide tables forever!"

So when is high tide in Georgetown, Bahamas?  

It depends on who you ask.  For example, on January 16, 2016 (departing Red Shanks anchorage):

11:15 am Navionics chart plotter gave high tide at “Exuma Harbour” 

12:18 pm Pavlidis Appendix E, Nassau 12:38 - 0:20

12:37 pm Dept of Meteorology (“Exumas”)  = Nassau -0:01 

12:38 pm Yachtsman’s Guide to the Bahamas = Nassau

12:45 pm Garmin at “Steventon” (“14 miles from chart center”—North, Nassau + 7)

12:53 pm BahamasCruisersGuide.com  (Nassau 12:38 + 15)

12:58 pm local & charter captain (Nassau + 20)

1:21 pm The Net says Nassau 12:38 + 45 

(Thornless:  The next full moon is Jan 24, so high tide should be 8:00 if "near open ocean". NOAA has high tide at Nassau as 7:51)

That’s a 2-hour difference!  A local told me that high tide can be different at either end of the harbor. If you use the Thornless explanation of "near open ocean" this makes sense. The Northern entrance is the Exuma Sound (very close to the ocean) and the southern cut is very shallow water ("the banks", 11 ft) 

Why do I care?

Anchoring:  While anchoring, we need to know where we are in the cycle. Do we need to factor an additional 3 ft into our depth while calculating our 7:1 scope?  Or will it be 3 ft less under the keels than what our depth finder is reading? If there is a Supermoon or derecho (1 meter = 3 ft x 7 = 24 ft) it could be the difference between dragging anchor or not dragging (ask the catamaran next to us in Lake Worth!)

Skinny water:  Many cuts can be shallow, requiring a high tide to safely navigate through. (Others can have a significant current, requiring slack water to be navigable--another topic, but you definitely do not want to transit during the rage). The ICW also has areas that silt in, requiring high tide to avoid going aground (until it can be dredged again). Some excellent anchorages have a shallow entrance, requiring high tide to enter, but deep water once inside (RedShanks).

At a dock:  If you are at a fixed dock, and tie up at low tide, lines have to be secured with the idea that the boat will rise 3 ft at some point (usually in the middle of the night) possibly straining lines, stanchions or fenders.

Clearing bridges:  Our catamaran (47 ft mast) was in winter storage at a primarily-powerboat marina, with a bridge height just before the entrance of 53 ft. Our visit to the Albemarle Sound had us scooting under the Plymouth, NC 50 ft bridge to ride out the remnants of a Tropical Storm at the sheltered and free town dock.

The moral of the story:
Question your chartplotter.
Question the tide tables.
Confirm the location of the tide info given.
Confirm the source of the info.
Take into consideration the moon phase and weather (especially barometric & wind)
Take into consideration the range of tidal swing (2 ft or 8 ft?)

Compare the depth finder to your charts

Compare the depth finder to tide table
Keep a log
Look around--not just while anchoring but frequently throughout the day to get a feel for the area.
Ask a local fisherman or charter captain:  I've tried this and I get a lot of shoulder shrugs. "It is, when it is." Here's how they do it: visually.  Look at landmarks, pilings, limestone (water marks), sand bars/reef, slime on the side of buildings (visible?  low tide.  Not visible?  high tide)

We've also been known to stand on our stern step and attempt to "stick the bottom" with the boat hook.  We've also snorkelled down to take a look--in very shallow water, we can approximate how much water is under our keels or even stand up!

Don't get me started on low tide vs slack water.