Hurricane Irma Reaches 185 MPH, Trailing Only Allen As Strongest Atlantic Storm On Record (arstechnica.com)

An anonymous reader quotes a report from Ars Technica: We are quickly running out of adjectives to describe the destructive potential of Hurricane Irma. As of 2pm ET on Tuesday, the National Hurricane Center upgraded the storm's sustained winds to 185mph. This is near-record speed for a storm in the Atlantic basin, which includes the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. Such high, sustained winds tie Irma for the second-strongest storm on record in the Atlantic, along with Hurricane Wilma (2005), Hurricane Gilbert (1998), and the 1935 Florida Keys hurricane. Only Hurricane Allen, which reached 190 mph in 1980 before striking a relatively unpopulated area of Texas, reached a higher wind speed. Globally, the all-time record for hurricanes is held by Patricia, which reached a staggering 215 mph in the Pacific Ocean in 2015. Although sustained winds capture the most public attention, meteorologists generally measure the intensity of a storm based upon central pressures, which are considerably lower than sea-level pressure on Earth, 1,013 millibars. Typhoon Tip, in 1979, holds this record at 870 millibars. For now, at least, Irma has a relatively high central pressure of 927 millibars. Why the storm has such an odd wind-speed-pressure relationship isn't entirely clear. According to the National Hurricane Center, Irma is expected to bring catastrophic winds and potential storm surges to the U.S. Virgin Islands, Puerto Rico, Dominican Republic, and the UK territory of Turks and Caicos this week. The Florida Keys could get hit by late Saturday night or Sunday.

Comments

Camille

[cirby]

...probably reached 200 MPH, but the instruments at Keesler AFB were blown away when Camille hit Biloxi, so they can't count "sustained wind speed."

Re:Camille

[ShanghaiBill]

I remember Camille. My mom woke me up at 2am, and told me to grab everything I own and take it upstairs. The flood waters from the neighborhood creek were already at our front porch. About 10 minutes later, muddy water started gurgling out of the heater vents on the floor of my bedroom. The water rose another 30cm over the next few hours.

My room was a muddy mess the next morning. But it was worth it because school was cancelled for a week.

This was more than 400 km from landfall.

I happened almost exactly a month after Apollo 11 landed on the moon.

Re:Camille

[PopeRatzo]

the instruments at Keesler AFB were blown away when Camille hit Biloxi

I just moved out of Houston and I was there for Hurricane Harvey. When it hit Corpus Christie, every weather station from there to Galveston was just blown away. And that was "only" a Category Four.

I never want to be near a hurricane like that again. It scared the crap out of me. We were supposed to have moved (driving to the California Central Coast) the day before Harvey hit, and it obliterated our schedule. Couldn't leave town until a week later when the water receded enough off the highways that one lane of traffic could get out. Tons of people were still evacuating, because the "controlled" release of water from the reservoirs was flooding neighborhoods that hadn't flooded during the initial 50+ inches of rain. It took us the entire first day of driving just to get out of Houston city limits and all together, after a day of driving, we only got as far as College Station.

We just arrived in our new place in Cali today. There are wildfires a few hundred miles away, but here where I am, right on the coast, there's no danger of burning. At least that what I'm told. Screw natural disasters. I don't like 'em one bit, no sir. Did you know that the constant sound of heavy rain on the windows for five solid days can make you completely insane?

Re:Local meterologist

[Geoffrey.landis]

Uh, that's not quite the way hurricanes work. They don't "slam into" something and stop. Caribbean islands are small compared to hurricanes!

They stop when they traverse a region where they are separated from the warm ocean, which is (in essence) their power source.

Re:Two storms of unusual magnitude ....

[whoever57]

First it was Global Cooling until that fell flat on it's face.

What fell flat on its face is your knowledge of history. In fact, scientists did not predict cooling: that was only the media.

However, these are media articles, not scientific studies. A survey of peer reviewed scientific papers from 1965 to 1979 show that few papers predicted global cooling (7 in total). Significantly more papers (42 in total) predicted global warming (Peterson 2008). The large majority of climate research in the 1970s predicted the Earth would warm as a consequence of CO2. Rather than 1970s scientists predicting cooling, the opposite is the case.

Let me suggest that you crawl back under your bridge.

Re:Two storms of unusual magnitude ....

[Anonymous Coward]

Doctor A: If you don't stop smoking, you'll die within 10 years.
Doctor B: If you don't stop smoking, you'll die within 5 years.
Patient: "Sheesh, I knew all the smoking paranoia was hokum... the doctors can't even agree"

You tell me, how does a scientist describe increased variability in climate changes? Yes, it's still going to rain, it's still going to snow. There will be hurricanes. But long-term trend changes are observable and they are alarming. The highs get higher and severity of events will increase. And even when models are inaccurate, they are consistently inaccurate pointing to the same concern. No, humans can't destroy the earth, but we can make it a pretty damn difficult place for us to live on.

Difficult to forecast Irma

[Anonymous Coward]

This is a really difficult forecast for a number of reasons.

Most major hurricanes don't just gradually intensify to a category 3 or 4, let alone well into category 5. They undergo periods of rapid intensification, due to bursts of thunderstorms in the core of the storm with lots of hot towers developing. Harvey did this before making landfall in Texas. Irma has done this twice. However, forecasting when this will happen is generally beyond the current limits of meteorology. The Ships statistical model only called for a gradual intensification of Irma. Some of the dynamical models like the GFS, HWRF, and HMON did predict rapid intensification. However, they have been predicting that it was imminent for days, without actually happening. It's obvious when rapid intensification is occurring because the hot towers show up in infrared satellite imagery. But there's very little skill in predicting rapid intensification before it starts. It's related somewhat to ocean heat content, but it doesn't explain when there's high ocean heat content but rapid intensification doesn't occur. Most major hurricanes do undergo rapid intensification at some point, and it's very hard to predict.

It's very likely that Irma will take a hard right turn in a few days and move north. There is very good agreement among the models that this will occur. However, it's not clear exactly when this will happen. If it happens sooner, Irma could miss Florida entirely and move toward the Carolinas. This isn't especially likely, but it's possible. It could turn north a bit later and move across the Florida Keys into South Florida. There are also model solutions that bring Irma into the eastern Gulf of Mexico. This last situation also isn't especially likely, but is definitely possible. This doesn't include true outlier model forecasts, such as missing the United States entirely. Irma will also get close to Cuba, and moving over mountainous land for an extended period of time could wake Irma substantially. It just isn't clear yet whether this will happen or not. Hurricanes are steered by winds in the upper atmosphere around areas of high pressure (ridges) and low pressure (troughs). There are currently special upper air observations being taken every six hours in the central United States to help with forecasting Irma. There's an upper level trough over its area, that will interact with a ridge to the east, which has an impact on steering Irma. It's not clear whether these extra observations are helping with the forecasting of Irma, but it's definitely possible. Maybe these types of special observations well over a thousand miles from a storm have been taken before, but I don't recall seeing it. It's a very interesting idea for sure, to try to help improve forecasting of the storm's track in the 3-7 day time frame. Even though we know Irma will very likely take a hard turn to the north, relatively small differences in where this occurs will have a big difference on the impacts to the United States. And this is not at all unusual in hurricane forecasting.

Despite running tens of different computer models every six hours, it's really hard to predict where the storm is going to go. And yet the track forecasting has improved quite a bit over the past couple of decades, definitely outpacing intensity forecasts.