• 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 Florence

Oct 19, 2017
7,733
O'Day 19 Littleton, NH
How do hurricanes typically behave when they cross Gulf Stream waters? That massive river of warm water must be putting up a wall of warming rising air. Do they absorb the energy and intensity or do they slow and change course to follow?
I've heard speculation about Florence stalling mid Atlantic and just sitting there. With the continental high ahead of her, do you think this is possible?

-Will ("ever the optimist", Dragonfly)
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
H.Florence will be crossing 85deg F water as it approaches the coast, that heat will fuel the hurricane and strengthen it, not slow it. Shearing upper-level SW winds will be affecting how much strength it can build, and continental high pressure has already caused the computer models to predict it will steer further south. NHC is now depicting the coarse to steer out across North Carolina. Current track speeds are 15 mph, if the high stuffs the storm it will camp out on North Carolina/South Carolina and likely increase the predicted rainfall totals as it streams ashore.
 
Oct 19, 2017
7,733
O'Day 19 Littleton, NH
I'm glad, right now, I didn't buy a place on the Outer Banks. I hope everyone is prepared. When Hugo hit Charleston, it had no trouble at all reaching us in Winston-Salem with plenty of wind and rain and tree toppling power. I don't think the city was prepared for that. With hurricanes, 300 miles is not enough buffer.

-Will (Dragonfly)
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
The water temperature near shore by me right now is just north of 84 degrees. 6 miles out, it is just north of 87 degrees. Yesterday there was a 9 knot north current 6 miles out (not a typo). Normal north current there is 1-3 knots.

There is a small disturbance just NE of the main storm now being shown on the NHC charts. I will be watching to see if this pushes the storm further south. The water to the south is warm enough to make the storm really blossom.
 
Jan 1, 2006
7,040
Slickcraft 26 Sailfish
... When Hugo hit Charleston, it had no trouble at all reaching us in Winston-Salem with plenty of wind and rain and tree toppling power.../QUOTE]
Or Springfield Ohio where we were. Maybe not tree toppling but a notable storm. I remember thinking I'm used to worrying about hurricanes on Long Island, but in Ohio?
 
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Feb 14, 2014
7,400
Hunter 430 Waveland, MS
This is the current Hurricane Hunters Mission #11 into Florence on going NOW.
recon_AF306-1106A-FLORENCE_timeseries.png

1) How many times have they passed near the EYE?
2) What was the aircraft real Altitude?
3) At what time [point] was the greatest intensification potential?

This is the REAL Data, not satellite.

Dammit Jim...

PS: Hints MSLP=Mean Sea Level Pressure, SFMR= Microwave Surface wind Speed. mb=millibars=hPa, kts*1.15 = mph
 
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Jan 1, 2006
7,040
Slickcraft 26 Sailfish
Twice through the eye?
Altitude? I'd like to say 32000 feet. But the altitude is in meters. I don't know what Geopotential Height is even after reading the definition.
Intensification 14:57?
 

Johann

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Jun 3, 2004
420
Leopard 39 Pensacola
If I’m reading the pressure/alt graph correctly, they are flying a constant pressure altitude (ie with ref to a barometric altimeter) not a constant height (radar altimeter). The geopotential altitude is actual height above MSL I believe, which is varying significantly with the pressure change.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
upload_2018-9-12_12-45-49.gif


Look at the spaghetti model tracks. NOAA is hanging onto their current predicted track but the European model is depicting the skipping hurricane concept that sent H. Matthew up the coast and into South Carolina. THIS is why we give hurricanes a name, they have a mind of their own. South Carolina is now in the target zone and Atlanta is looking threatened. Later it looks like the hill country of South Carolina and East Tennessee before it either goes east across Virginia or into the northeast via the Ohio River valley.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
not a constant height
They fly, as best they can Constant height. the lower right graph is inside the aircraft mb pressure

European model is depicting the skipping hurricane concept
For a reference, that same combined model is linked on my post#13, Last Friday. Note my "PS" on the TABD model.
Wait a minute they changed the European model designator to EECF????

.
 

Johann

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Jun 3, 2004
420
Leopard 39 Pensacola
They fly, as best they can Constant height. the lower right graph is inside the aircraft mb pressure
.
The graph shows the light line as “height” which is varying, and the dark line as “pressure” which is steady. The constant pressure corresponds to a barometric altitude of 10000’ with an altimeter setting of 1013 hpa. So I still think they are flying via baro altitude at 10000’. I’m pretty sure my dad said that’s how they did it in the 70’s when he was in the 53rd/54th WRS. Still, with the new WC J models maybe they have new capabilities for constant “height” flying.
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
with the new WC J models maybe they have new capabilities for constant “height” flying.
Yes. More control less seat of your Pants flying. Makes the geek guys in the lab happy.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
This is the best description of what is happening to Florence.

This guy know his stuff. It is long, but includes ALL of NOAAs points of tracking

Dammit Jim...

PS: It says 9/11/2018 but is today early.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Wait a minute they changed the European model designator to EECF????
storm_06_ens.gif

This one is the only one I saved. Note the date in lower left corner when compared to @Gunni above
ECMF=>EECF ???
I am still looking for that change reason.

The turning KEY is still the HIGH Pressure on the NORTH which is moving East by North East.
Dammit Jim...

PS: I still like the TABD triangle model from Gunni's post. About the same as NHC circles.
 

Sailm8

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Feb 21, 2008
1,746
Hunter 29.5 Punta Gorda
We have been through 2 big hurricanes and numerous TS. Get out. The aftermath is worse than the hurricanes. Weeks without power. Toilets won't flush and no water. Even if your boat is well prepared it is at the mercy of the boats that weren't. We had boats from half a mile away come along and sink well-prepared boats. There is no rhyme or reason to what will happen. You can't drive without getting a flat. Be safe. I wish you the best.
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
I just looked at the Windy.com version of the ECMWF modeling (likely 12 hrs old) and it is showing the storm dancing down the coast from NC to SC till Saturday still unclear if it will hang around or head inland.

upload_2018-9-12_15-47-39.jpeg

upload_2018-9-12_15-47-56.jpeg

upload_2018-9-12_15-48-16.jpeg
 
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Jan 1, 2006
7,040
Slickcraft 26 Sailfish
I don't know anything about hurricane dynamics but I hope that the fact that it will stall near land will mean the winds will be northerly or north west on the weak quadrant, which will hopefully weaken the storm. Still the amount of rain is scary. With Isabell we saw what torrential rain can do in Vermont and upstate New York. Ski lift poles were washed away. My friend's town in Londonderry Vermont became an island. These areas were many miles away from the eye. I believe the rain bands can be a long way away from the storm center. It's awful. Be safe. It's not going to be easy.
 
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