[ Post a Response | FLSC Message Board ]
Posted by Ray
on 12/30/2011, 7:57 am
74.65.47.166
....like a Lion! The question for Sunday is not, "will there be enough wind for wave?" Rather, it's "will there be too much wind to fly at all?". Tomorrow, wind won't be a problem. But crappy and IFR in the morning, albeit OK later in the PM.
The flow at 500mb across the eastern Pacific and continental US is quasi-zonal: more or less east-west, no big troughs, but lots of little (relatively) kinks ("short wave troughs" or "vorticity maxima" in the lingo). Now in general the translational speed of such waves is inversely proportional to their amplitude, and this weekend is a text book case. Am not going to spend three pages discussing the flow evolution at various levels for the next three days...but it is fascinating to see...and geeks are strongly encouraged to. The culprit for Sunday was, at 7 PM last night, just a little vort max, out over the Pacific, in line with the US-Canada border, and about 200 miles offshore. But it is a speed demon: by tomorrow morning it spans Idaho/Wyoming, and by Sunday morning it's reached the Great Lakes! Now the GFS and NAM agree closely out to 60 hours (1200 UTC Sunday). They also agree after that, as to the general shape of the isobars...but not at all to the spacing, i.e. the wind strength. At 925mb for example (just above the ridge), the NAM has 20-30 knots WSW reaching western NY...but the GFS, for the same time and place, has 50-60 knots (holy crap!). Which of these two models verifies is crucial for us of course. Notice that everyone is talking about the cold front crossing NY state on Sunday, but no one, including NWS Buffalo, is saying when. And this is why. Anyway: even if the GFS winds verify, the front probably won't cross first thing in the AM. That, in conjunction with the fact that KDSV sits sheltered in the valley from crosswinds, means we'll probably be able to get some early tows off...but expect to get kicked hard on tow. You may get early ridge lift...but if you stay on it too long, you might not want to land...but when the front comes in, you would have to. Get the idea?
Because of all the above, we definitely need another 24 hours of model output, and analysis thereof, to better pin down when Sunday's front comes in. And you will get it, tomorrow AM.
Message Thread
« Back to index