• Sailing is all about the Weather.

    Big into the exploration of Atlantic Hurricanes since Katrina came uninvited into his world, James (Jim) Gurley (JamesG161) has followed every Tropical Storm birthed in Atlantic, Gulf and Caribbean waters since. Being a boater, he knows that we often need more time to prepare than we get from the TV weather folk. Jim relies on the science of storm development to share early warning info with friends and fellow boaters.

    Early in 2018, Jim and John Shepard, (JSSailem) started to chat about the weather data available. John asked Jim to help forecast Pacific NW storms, and this morphed into discussions on weather forecasting.

    For John, sailing in the PNW is sometimes hit and miss. One day is ugly, then a string of beautiful days but no wind, followed by a series of blue-sky days and 12 knot breezes. Being ready for those great sailing days means you need to look to the Pacific Ocean and what is brewing. John has been into Pacific NW Weather since the 1970’s when his first PNW November storm hit bringing more than 40 days and 40 nights of continual rain.

    Together we want to share information, new APPs, safety, and thoughts about letting the weather help you. Identify some of the resources for sailors and help prepare you for your next sailboat outing.

    It is far better to go out on the water knowing what to expect in weather terms, than to be out on the water and see dark ominous clouds suddenly appear, unprepared.

Hurricane Dorian <-- TS<--TD 5 <-- Invest 99L

JamesG161

JamesG161

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Feb 14, 2014
7,418
Hunter 430 Waveland, MS
capta said:
You are implying that the Antilles Current (variable) and the Gulfstream (2.5 knot average) won't be replenishing that heat pretty quickly? I'm not sure I'd take that bet. lol
Click to expand
So to show @capta good point on the Gulf Stream, here is a graphic update to my post #74

cdas-sflux_ssta7diff_watl_1-2.png


I like to think of the Gulf Stream as a Heat Pipe line, fast and full of Heat from the south Caribbean Fuel Tank.

The big difference is the Storm Surface Area of Heat Fuel Removal versus the replenishment by the Gulf Stream.

Two other Keys to lowering 2019 season intensity
1) many small Gulf disturbances that rain a lot
2) very "quiet" Sun and low Solar activity;)
3) Storms mix up the deeper Heat, blending from cooler temperatures below.
Jim...
 
capta

capta

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Jun 4, 2009
4,772
Pearson 530 Admiralty Bay, Bequia SVG
According to that, the Abacos area is already back to being very warm. In most cases the tropical cyclonic events I've experienced have been followed by extremely hot, still and humid conditions, which must also replenish the heat a bit more quickly.
 
JamesG161

JamesG161

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Feb 14, 2014
7,418
Hunter 430 Waveland, MS
JamesG161 said:
Storms mix up the deeper Heat
Click to expand
Heat is Energy content. Even cooler waters have Heat, just cooler.
____
capta said:
According to that, the Abacos area is already back to being very warm.
Click to expand
Very true, it is Summer still.
But...
Heat removed.

That chart is what Meteorologist use to study Sea Surface Temperatures Variations versus a agreed upon standard.
That Standard is the Average of the period 1981-2010.
Why that time range?
Satellite measurements. Earlier years not so globally done.

ohc_naQG3_ddc-3.gif

Heat content versus SST Anomalies.
This is done by Two Satellites used together since about 1980.
Look at the Caribbean Fuel now. But note less influence by the Gulf Stream.
Jim...
 
capta

capta

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Jun 4, 2009
4,772
Pearson 530 Admiralty Bay, Bequia SVG
Not to be argumentative, just for the conversation, wouldn't you expect the majority of the heat sitting under Cuba around the Caymans and Jamaica to be picked up by the stream and carried north pretty quickly considering the average Gulfstream speed of around 2.5 knots?
I haven't been following this map, so I have no idea what has caused the pause north of Cuba in the stream to create this warm pool.
It must really be killing the offshore fishing in the Keys. Time to get out the flats boats.
 
JamesG161

JamesG161

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Feb 14, 2014
7,418
Hunter 430 Waveland, MS
capta said:
just for the conversation, wouldn't you expect the majority of the heat sitting under Cuba around the Caymans and Jamaica to be picked up by the stream and carried north pretty quickly considering the average Gulfstream speed of around 2.5 knots?
Click to expand
Absolutely!!
But think like a Diesel Fuel tank. Gulf Steam is draining Heat from the Big Tank [not majority drain tho]. All along the Gulf Stream that Heat is spreading out too.
_____
capta said:
so I have no idea what has caused the pause north of Cuba in the stream to create this warm pool.
Click to expand
The spot in Central Gulf is the Heat "Swirl" then the Stream goes around FL. And the Gulf is Very Deep at the return point.
Mixing.
Jim...
 
jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
Good point Capta... The Gulfstream is a big mover of the Caribbean heat.
Screen Shot 2019-09-14 at 9.58.32 AM.png


But the Gulfstream is not moving at a constant speed it is influened by Low Pressure cells. The cells when big enough and spinning in a counter clockwise direction can influence even the Gulfstream. As seen in image 2 off the Central East coast of Florida. Slowing the stream down to 0.9knt and evening causing it to swirl out and away from its primary route NE along the coast.

Screen Shot 2019-09-14 at 10.02.06 AM.png
 
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capta

capta

.
Jun 4, 2009
4,772
Pearson 530 Admiralty Bay, Bequia SVG
Oh, I don't disagree at all about fluctuations in the stream's speed, as I have personally experienced one crossing from the Northeast/Northwest Providence channel to Lauderdale where my landfall was North Miami Beach (where oh where are the smokestacks when you really need them?), meaning no current at all on the trip. On the other hand, coming back from Brazil on my freighter, my original pilot meeting time of about 9 PM at Palm Beach A buoy was pushed ahead repeatedly as it became apparent that the stream was running at around 8 knots!
I just use the 2.5 as an average between Mexico and western Cuba to Cape Hatteras or so. Very general, but serviceable.
 
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jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
It is an ocean and it will be changing. We as sailors need to adapt.

The info was provided to help understand the variances of the current and the Low pressure cells that are stirring up the weather we are all following. It is easy to be wow'd by the surface storm. Dorian was a great example. At the surface it was doing one thing, at 5000 to 10000 feet it was doing something totally different. Why there were so many HH flights to try and understand what the storm was doing. All the while it was changing the under water conditions of the of the Caribbean Heat source for the storm.

The plots give a bit of information about the water currents that influence the area and the weather.
 
JamesG161

JamesG161

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Feb 14, 2014
7,418
Hunter 430 Waveland, MS
jssailem said:
The Gulfstream is a big mover of the Caribbean heat.
Click to expand
Pretty cool use of Windy.com. I will see if i can get the SST Anomaly combined.

Also note that Cool Calm Heat area North of Havana is influenced by the Everglades rain fall run off.
 
BlowMeAway

BlowMeAway

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Nov 30, 2015
1,337
Hunter 1978 H30 Cherubini, Treman Marina, Ithaca, NY
Jim/John, What’s up with Humberto? Dorian killed our spring plans for the Abacos bare boat trip. I guess it’s back to the BVI in 2020. Windy.com rules!
 
jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
NOAA is saying...
"Tropical Force winds and Heavy Rain."
Current path has it running north of the Bahamas on a similar path as taken by Dorian.
Not currently forecasted to have the strength of Dorian. But all of this can change. Follow the advice of your local officials.
 
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