Saturday, 24 October 2015

Hurricane Patricia’s Epic Bombification

Patricia’s Epic Bombification — Monster El Nino + Climate Change Serves Up Strongest Western Hemisphere Hurricane Ever

Now this is scary. A tragic development you’d tend to see in a disaster movie screenplay and not in any typical meteorological record for any 36 hour period. But here we have it.
23 October, 2015
Patricia, as of 36 hours ago, was a rather mild tropical storm churning through the human hothouse and El Nino warmed Eastern Pacific. The storm was predicted to make landfall in Western Mexico as a hurricane, then turn north into Texas, Louisiana and Mississippi — dumping extreme rains over a drought stricken region. But there was little hint as to what would happen next.

(Patricia becomes the strongest Western Hemisphere storm ever recorded as it sets sights on a swath from the Pacific Mexican Coast and on through to Texas, Louisiana, Mississippi and Arkansas. Video Source.)

Favorable atmospheric conditions and next to zero wind shear set the stage for strengthening. But the main driver was the hot ocean water which Patricia could tap as fuel for rapid intensification. For the entire region now features ocean surface temperatures in the range of 30 to 31 C (86 to 88 F) or about 2-3 degrees Celsius above average. It’s heat fed by an El Nino that could be one of the top three strongest on record. Heat further intensified by a human forced warming of the globe that has now hit about 1 C above 1880s levels. Heat that would allow Patricia to hit never before seen heights of storm force in a period of extraordinarily rapid intensification.
They call it bombification for a reason. Pressures drop rapidly, wind speeds rage to epic force, and the storm presents a tell-tale angry red signature in the infrared satellite shot. During recent years, bombification has become an all-too-common word associated with ocean storms that are now feeding on unprecedented amounts of heat, moisture, and temperature differentials. Some have even claimed that Hansen’s terrifying ‘Storms of My Grandchildren’ are starting to arrive early. But what happened with Patricia was even outside the new abnormal bombification ‘norm.’
Though weather models did forecast a rapid strengthening for Patricia, the kind of strengthening we ended up with was something both freakish and extraordinary. In a 36 hour period pressures plunged from a mild 990s mb storm to a system featuring an 880 mb minimum central pressure. This raging period of ocean-shattering intensification propelled Patricia to a dubious status of most intense storm ever recorded for the Western Hemisphere over centuries of barometric readings. Winds also rapidly strengthened — roaring up from 40 miles per hour to a current top intensity of 200 miles per hour. That’s 160 mph of wind intensification in a little more than 36 hours.

At current intensity, the storm is now comparable to the monster western Pacific Storms — Haiyan (195 mph and about 890 mb) and Tip (195 mph and 870 mb) — otherwise known as the strongest storms ever recorded. And all this fury now aimed at a well-populated swath from the Pacific Coast of Mexico through to the Gulf Coast of the United States.
An Unimaginably Dangerous Storm Following a Ridiculously Dangerous Path
The potential for tragedy in this situation cannot be understated. A similar strength Hurricane Haiyan — also fueled by abnormally hot waters made hotter by human-forced warming — rendered tens of thousands homeless even as it resulted in the horrible loss of 6,000 souls.
Patricia falls into this high-danger category for a few reasons. The first is that the storm is expected to maintain its extreme Category 5 intensity all the way through to landfall — which is predicted to occur within the next 10-12 hours. Abnormally intense ocean heat content along the path of Patricia, as seen in the graphic below, will continue to provide the powerful storm with fuel as it encroaches upon the Mexico Coast.
Ocean Heat Content and Patricia Track
(Ocean heat content and predicted storm path by Colorado State University.)
As a result, a 15-30 mile swath of the Mexican coast may experience sustained winds near or in excess of 200 mph with gusts up to as high as 250 mph. That’s tornado intensity winds but spread out over an area the size of a small state. Storm surges and related onshore waves are expected to be ‘catastrophic’ (the National Hurricane Center’s words). How catastrophic is unclear (no specific surge height predictions are given), but taking such extreme wind speeds and low pressures into account, we could certainly expect surges near and to the right side of the storm center to be in excess of 20 feet.

As Patricia begins to interact with the mountainous terrain near the coast, it should begin to weaken even as it dumps heavy rainfall over a broad region. Already, moisture and storm outflow from Patricia are being caught up in the Jet Stream and pulled north and eastward over Texas. By Sunday, the remnants of Patricia are expected to combine with a non-tropical cyclone which is predicted to, in turn, dump between 5 and 9 inches of rain over a wide section of Texas, Louisiana and Arkansas.
Severe rainfall Texas
(NOAA 5 day precipitation forecasts show severe rains hitting drought stricken regions of Texas, Arkansas and Lousiana as the remnants of Patrica track northward. Image source:NOAA.)

These rains will provide yet one more weather whiplash to a region that experienced severe flooding this past Winter and Spring only to be replaced by severe flash drought conditions and extreme wildfire outbreaks during late summer and early fall. Patricia’s expected flooding rains will begin what is expected to be an extremely wet Winter for the region — providing no relief for the highly varied conditions that have impacted the region for some time now. The kind of extreme weather variation that scientists warned was also a potential upshot of human-forced climate change. And, in this case, a record strength storm fueled by a near record El Nino, forming in a record hot world, and feeding on record hot Pacific Ocean waters is the delivery mechanism for the predicted switch.
(Updates to Follow)
Hat Tip to DT Lange
Hat Tip to Greg

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