Wednesday, November 25, 2015

Storm stalking update

The Gulfstream IV, operated by the National Oceanic and Atmospheric Administration, just flew over a jet-stream wind of 138 m.p.h., stronger than that of a Category 3 hurricane.

Storm stalking update


The government jet prowling the atmosphere over the North Pacific now is riding above a solid cloud mass and probes directly into the  upper-level weather system affecting Northern California.

The Gulfstream IV, operated by the National Oceanic and Atmospheric  Administration, just flew over a jet-stream wind of 138 m.p.h., stronger than that of a Category 3 hurricane.

Those strong winds, measured about 1,600 miles northeast of Honolulu,  are on the east side of the upper-level that is giving a kick to the  system now affecting northern California.

That same feature may bring what flight meteorologist Jessica Williams  describes as a "heavy precipitation event" to her hometown, Willow  Grove, and the rest of the Philadelphia region by Sunday.

Her best guess right now would be rain, but coming up with a more-precise answer obviously is an important one, and Williams says that's one reason the Gulfstream IV is up here.

That wind reading is significant, because the U.S. computer model yesterday was forecasting a wind of about 120 m.p.h.

But the tiny computer board on the  "dropsonde" device, about 18 inches long and 2 ½ inches in diameter, came back with the 138 m.p.h.  real-time reading. That's a significant difference.

In the end, the details that can make all the difference in a forecast as a system moves downstream.

Inquirer Weather Columnist
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Everyone talks about the weather, and here we write about it.

When we’re around and conditions warrant, we’ll keep you updated about what’s coming, but we will do our best always to discuss weather and climate developments in context and remind you that nothing in the atmosphere happens in a vacuum.

Tony Wood has been writing about the atmosphere for The Inquirer for 26 years.

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