A tragedy happen yesterday (Sunday, September 4) with the crash of a float airplane over Mutiny Bay of southern Whidbey Island simply after 3 PM (see map beneath, the star signifies the accident website).
The plane was en route from Friday Harbor to Renton. Like all plane accidents, will probably be examined comprehensively by the Nationwide Site visitors Security Board (NTSB), which may be very worthwhile. Flying is awfully secure as a result of the causes of previous accidents are painstakingly investigated and the system is improved because of this.
A number of people have requested me whether or not there was a meteorological contributor to this horrible prevalence, and after inspecting the info, I did discover one thing important.
Let me present you now.
Throughout the precise time of the accident a entrance was shifting by way of the regon, and this passage, interacting with native terrain, produced a really sharp low-level wind shift within the lee of the Olympics.
Listed below are the floor observations at 3 PM. To the south of the accident website the winds have been from the south (the barbs face the route from which the wind is coming) whereas to the north the winds have been from the northwest.
Temperatures have been a lot hotter within the southerly move in comparison with the northerly move.
Such convergence of low-level airflow typically accompanies frontal passage over Puget Sound and infrequently produces a band of clouds and precipitation: the notorious Puget Sound Convergence Zone.
This transition could be very sharp, as a cool wedge of chilly, northerly air undercuts and pushes apart hotter southerly move (see schematic vertical cross part beneath).
To see how sharp the transition was, let me present you the observations from a floor observing location (Bush Level), simply north of Mutiny Bay (courtesy of the WeatherUnderground).
The underside panel is wind route. Wow… a VERY sharp, virtually instantaneous wind shift from southerly to northerly at 3 PM. The highest panel (pink line) reveals temperature, which plummeted after the windshift. Different close by observations confirmed the identical factor.
The seen satellite tv for pc picture 3 PM reveals a band of clouds related to the windshift line.
Actually not that spectacular and the climate radar confirmed no lively precipitation with the windshift line (see beneath).
3 PM climate radar
The vertical construction of the vanguard of the wind shift line (illustrated by the determine above) can be a slender wedge of northerly winds at low ranges, with the southerly winds proper above. Excessive-resolution UW WRF mannequin simulations indicated such a construction (see simulated sounding with peak at 2 PM for the purpose in query). The Camano Island radar famous the identical factor.
With all this meteorology in thoughts, let’s get again to the float airplane accident. Based on flightradar24 (beneath), the airplane was flying round 600 ft AGL, climbed to round 1000 ft, after which quickly misplaced altitude at 3:09 PM (2209 UTC). Plane velocity was round 125 knots earlier after which misplaced velocity simply after 3:08 PM.
Flying south that they had the northerly winds behind them. Then they hit the convergence zone line. Shifting from northerly to southerly winds might clarify their fast lack of velocity. Though their floor velocity would decline, their airspeed might improve, inflicting extra raise. Did that contribute to their rising elevation on the finish?
Not solely did the wind reverse immediately, however there would have been appreciable turbulence as a result of robust vertical wind shear related to the convergence/windshift line.
Did this have something to do with this accident? I have no idea. All I can say is that the accident occurred in an space of an lively wind shift and potential low-level turbulence.
