Friday, October 23, 2015

Hurricane Patricia Most Powerful Ever; Not A Wind Event For Houston But Flooding Dangers Are Real Enough

Hurricane Patricia, approaching the Pacific coast of Mexico with possible catastrophic results there and the possibility of dangerous winds on the Texas coast and rain events tracking northeast across Texas and other states, is the most powerful weather events ever recorded. Right now, Friday at about 5:00PM Central time, it is a category 5 hurricane, the highest possible on the Saffir-Simpson scale, with current winds of... get this... 190 mph with gusts to 240 mph (that's tornado-like, said one meteorologist) and comparably low barometric pressures measured at the center (by dropped barometers, not aircraft, thank goodness). [UPDATE from Weather Underground: "At 2:30 pm Friday afternoon, October 23, 2015, a NOAA hurricane hunter aircraft measured a central pressure of 879 mb--the lowest pressure ever measured in a hurricane in the Western Hemisphere." Wow.]

That said, I hope you can set your mind at ease about our hazards from this awesome, awful storm: long before it reaches us, for example 1:00AM CT Sunday just prior to its reaching the Mexico-Texas border, winds will probably be 35-40 mph... not even quite tropical storm level. (See map above for forecast extent of tropical storm winds.) That's according to KHOU-TV, which still guests well-known retired meteorologist and acknowledged hurricane expert Dr. Neal Frank and employs several other very respectable younger meteorologists also with tropical expertise and experience.

The rainfall could be a very different matter. Houston's bayous have been successfully engineered over more than 50 years to cope with rains as high as 8" per hour and may... may... be able to withstand as high as 12" per hour in many parts of the city. But the forecast for this event? Between 11" and 15" per hour at its peak. Why such a wide range of possibilities? Well, for one thing, we're talking about tropical rain and South Texas topography here; it's not that easy to forecast in the best of circumstances. For another thing, Houston is a gigantic, spread-out city; people who talk about the "eight-county metropolitan area" are not speaking just metaphorically. Houston is huge. Worse still, its topography is highly diverse... it won't do to forecast one rainfall rate for the whole city because it doesn't work that way.

Of course I'll continue to post as long as we have power, which may be straight through the event... or not. We have food, water, a fairly elevated location within the city, a house that has survived several hurricanes of categories 1 through 3 over the years, a deep and well-engineered bayou near enough to absorb considerable runoff and far enough that we won't flood just by its proximity. As for gasoline, I'm determined neither of us will use any; the city's orders are for citizens NOT to evacuate but to stay home. Those of you who live along coasts know the drill; those of you who live where other kinds of severe storms occur can at least conceive of it.

I'll let you know what we experience. If we lose power and can't use the usual web interface, I can use a cell phone to post a line or two on this blog... ugly but functional. Or maybe Stella will lend me her iPad for a half hour...

Stay safe and dry, my friends. My prayers for the folks in Mexico who are choosing to stay in Patricia's path.

(I have made several post-posting corrections. - SB)

No comments:

Post a Comment


• Click here to view existing comments.
• Or enter your new rhyme or reason
in the new comment box here.
• Or click the first Reply link below an existing
comment or reply and type in the
new reply box provided.
• Scrolling manually up and down the page
is also OK.

Static Pages (About, Quotes, etc.)

No Police Like H•lmes