Weather Friday: YUCK.

Both IA and Shuttle reported moderate to severe turbulence between 11 and 1pm,  especially on approach to HYA from 3000 on down.  Things started getting nasty at 10am. Cape Air pulled the plug around 1030- 11.  Lots of pilot reports regarding significant wind shear and turbulence within the Cape and islands.  Not a day to fly for those with queasy stomachs. 

I called Island Air a few minutes ago. One of their pilots reported sever turbulence. They were on hold but thought that they might be able to fly later. 

I've been hearing planes but they might be private. Must be serious shear just off the deck. Any pilots or controllers want to chime in?

Last plane went around 10. Just made the Hyline. I'm not a boat person but it isn't too bad.

I should mention that visibilities may drop at the same time that possible window of lighter winds arrive which could hinder flights as well.

Very difficult call because of the approach of a very strong low level jet(stream) at just a couple thousand feet today. Several factors to consider. Actual wind speed and vector(relative to the alignment of the runway)on the surface, wind speed and vector as the planes climb or decend and flight level wind speed and vector. Also the density of the air at different elevations causing what's called an inversion layer.

My charts show a 30-50kt jet approaching at 9-11am from around 220-240 degrees at about 3000 ft. The puddle jumpers fly at 1000-1500 ft. With cold(sea) air at the surface and slightly warmer air aloft, an inversion sets up and doesn't allow those stronger winds to "mix" down to the surface(or flight level). No significant shear 11ish through 1ish, as surface winds are around 35kts from the same direction. So far so good.

From 2-4pm, the LLV jet increases to 80-90kts from around 240-250 degrees. The surface winds are still in the 35kt range from around 240 degrees so we start to see 30-40kts of almost uni-directional shear as the planes take-off on runway 24, ascend to flight level then land on 24 in HYA(or visa versa). Pilots discretion would come into play at this point. Probably doable, but on the fence. There will be a brief period late in this time-frame(a couple hours perhaps)where winds will be cranking and uni-directional shear will be causing flight interuptions.

Between 4:30-6:30pm we MAY have a period of diminishing winds both on the ground and aloft as the low pressure system moves near and past us. Very tough call but a few pilots may take advantage of the possible window.

From 7-10pm winds at the suface are veering into the WNW-NW as are winds aloft, although at different times. The inversion gets broken down because the air aloft is now colder than the surface air and the winds really howl as cold air advection mixes the strong winds aloft down to the surface. Wind speeds and shear will probably prohibit flights at this time. 

In a nutshell: 1. Get in before 3pm. 2. You might have a window late afternoon evening. 3. Probably no flights after 6-7pm.

Saturday will be breezy but I think flights will go.

NOTE: For those who don't know, I am not a met, so this event may not play out as written.

Yes at what point do you think no planes Nantucket to Hyannis?!?!

I got a missive through the Clerks' network today saying that at 5000 feet, the winds would be "screaming" at 100 mph.  They intimated that it could be dangerous for some flights. 

I'm happy to forward the email if you want.  I'm at flanaganstover@yahoo.com  if you email me, I will send it on.

QC

what he said...when are these winds supposed to kick in, and which boats might get cancelled, if you had to make a prediction?

Blair? Bueller?

SL