• 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.

Tropical Storm Arthur <-- Invest 90

Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Invest is a term that triggers computer models to focus on a Tropical Disturbance or, INVESTigation mode.
The number 90 is assigned by monitoring sections of the World. That number starts at 90 for Atlantic and Caribbean Section and will increment for each storm in 2020.
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Now on to the current storm, Invest 90.;)

It is raining in Southern Florida now and will develop into full blown LOW pressure system on Sat 16th, after passing over the Bahamas.
It will not develop beyond a small Tropical Storm named Arthur.

The best model, we track, has it going to North Atlantic by Tuesday 19th. [Note: We call this a "Fish Storm" not much impact on SBO boaters]

But...

Another LOW pressure will form over the Central USA on Tuesday 19th and will pass on to the Eastern seaboard giving the impression it was part of Invest 90. :badbad:

So expect some crappy weather from that trailing LOW buy Wed-Thurs on the Mid Atlantic coastal areas.
Jim...
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Of course it got a name.

TS Arthur

It appears to be giving North Carolina a Breezy Monday 18th, before heading away from Land.

News headlines strongly suggest early storms are an indication of big 2020 season.

Actually early storms are a good thing, in the sense of intensity.

Hurricanes are a Heat Engines, fueled by the Sun. Depleting the Heat by evaporation/rain cycle is a good thing.
ohc_naQG3_ddc-4.gif
That shows the Heat Potential on Arthur's path. Nothing to fire it up.

Sea Surface Temperatures [SST] are just that. Warm in the top ≈10 feet.

If you stir that SST up with wave action and mix with cold rain, the storm has to move or die.

Note: the only Heat Potential is the Caribbean, thus the area of the birth of TS Arthur.
Also note the African Atlantic now. Only along the Equator which is too far South for birthing there.

Jim...
 
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Feb 14, 2014
7,400
Hunter 430 Waveland, MS
TS Arthur begins to go South!

083231_5day_cone_no_line_and_wind.png
Why?

This is really a good example of pressure front timing. [pressure fronts are atmospheric waves]
Fronts move West to East at different velocities. Those speeds vary as the season changes.
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A second LOW pressure front, a bit further South today, will join TS Arthur in the next 2 days.
This is causing the curve.

No biggie because there is very little Heat to fuel the storm.
______
During the 2020 Hurricane season, we will discuss....

Timing is everything

In 2019, the USA was protected by HIGHs from the Pacific NW. Many storms, but few direct hits.
[ Dorian hit the Bahamas worst and 18 named Storms]

Jim...