Monday, August 20, 2007

The good news is: it's a side-swipe

Overnight, it has now become clear that Hurricane Dean in the end -- THANK GOD -- "only" side-swiped Jamaica, apparently curving a bit more to the West in so doing -- the Weather Underground satellite animation trended to Portland Point in southern Clarendon, on my take. Clarendon is Jamaica's physically largest parish.

("Semi-technical" note: Dean's track seemed to wobble between WNW and W, from out in the Atlantic on, indicating that the natural tendency to hook right for anything moving other than dead E or W in the Northern hemisphere -- an effect of so-called Coriolis Forces -- was being in part suppressed by steering forces, in this case the high pressure ridge to its north. BTW, there is a NOAA Mariners' 1-2-3 rule of thumb on hurricane track predictions: on days 1 to 3 out, the fan of likely deviations from the current track are 100, 200 and 300 nautical miles wide, which are about 1/5 bigger than statute miles. This is very useful for Cape Verde hurricanes, which tend to have a much more "predictable" track generally to W to WNW, hooking further as they reach either the NE Caribbean if they hit here, or towards the Gulf or Yucatan if they reach there, sometimes recurving all the way to the NE in the Gulf or in the US or off the E coast of the US. If the speed of advance is about 20 mph, that translates into roughly 500 miles per day, or about two days to cross the Caribbean from the EC to Jamaica. As a further, personal observation-based "rule," if hurricanes break into the region at about the level of Barbados, or if they have a very westerly track and break into the region a bit south of Antigua etc, they "often" seem to head Jamaica way -- in either case it seems the high Mountains of Hispaniola [?] and/or weather conditions to the north tend to steer them towards the S side of that Island, lining up Jamaica, the Caymans and Cuba as well as the Yucatan (which includes Belize). Hurricanes that go N of the region tend to head for the US E Coast and/or Bermuda. These are of course very rough personal impression pointers, and hurricanes are very hard to actually predict. Hurricanes that form in the W Caribbean off Honduras and Nicaragua etc, are far less predictable, from my impressions. I think the most notorious case in point in recent years was the zig-zagging Hurricane Gordon of 1994. That hurricane also underscores that it is not just wind that is damaging: rain and knock-on effects can be devastating too. In coastal areas, storm surges [up to 20+ feet with strong storms] and associated high sea waves that ride on the back of the surge [easily up to dozens of feet in some cases] have historically been major destroyers and killers too.)

Dr Jeff Masters of Weather Underground observed, as at 23:21 hrs GMT last evening [or 7:21 pm EC time or 6:21 pm Jamaica time]:
It could have been much worse, but it is very bad for Jamaica. Hurricane Dean's northern eyewall is just offshore the southern tip of Jamaica, bringing sustained Category 2 hurricane winds to southern Jamaica. A recent wind analysis prepared by NOAA's Hurricane Research Division (Figure 1) at 3:30pm EDT today shows winds of Category 1 strength (>65 knots, or 74 mph) already affecting the east end of the island. By extrapolating this wind field over the island to the west-northwest, in anticipation of Dean's track, it is apparent that perhaps 90% of the island will experience sustained winds of 74 mph or greater. At 4pm EDT, Kingston, on the southern side of the island, recorded sustained winds of 81 mph before the instrument failed. We can expect that the southern 1/3 of the island, including Kingston, will receive sustained winds of Category 2 strength--96 to 114 mph. Category 3 and higher winds will be confined to the southernmost 5% of the island, and it appears that the Category 4 winds will stay offshore. The portion of the island affected by the Category 3 winds is very sparsely populated.

Jamaica will probably suffer a billion dollars in damage from Dean, perhaps more. The high winds and rains of up to 20 inches will no doubt claim lives, though probably not nearly as many as the 45 who died during Hurricane Gilbert of 1988. Gilbert cut straight across Jamaica as a Category 3 hurricane with 125-130 mph winds, doing $4 billion in damage. Kingston measured sustained winds of 116 mph during Gilbert; I expect the top winds in Dean will be 10 mph slower than that. [NB: with a speed nearish to 100 mph and the physical science fact that power in the wind goes as the cube of wind speed, that makes for about 1/3 less destructive power, using the Taylor series expansion (for those who want to know where that comes from . . .). Of course, the official numbers on Gilbert were not necessarily the values experienced in particular sites, such as the Mona Campus where I was for Gilbert -- the winds as the eye turned were particularly impressive as I recall, perhaps in part due to funneling up the Hope river valley and rushing over the lip of the bluff.]
Now of course the Caymans are in the sights so to speak, and let us pray for God's protection there and onward in the Yucatan and Pinar del Rio Cuba, etc. AP/Yahoo adds to the above:
Authorities in the Cayman Islands imposed a curfew and evacuated tourists as the British territory braced for a brush Monday with Hurricane Dean, which has left a trail of destruction across the Caribbean killing at least eight people.

Dean was expected to pass to the south of the Caymans but the government said it still posed a "significant threat" to the islands. Forecasters said the islands could receive up to 12 inches of rain . . . .

The National Hurricane Center in Miami said the first hurricane of the Atlantic season was a powerful Category 4 storm, and could reach the highest level — Category 5, with maximum winds greater than 155 mph — later Monday.

As of 2 a.m. EDT Monday, Dean was about 150 miles southeast of Grand Cayman and was traveling west at 20 mph, the U.S. National Hurricane Center said. The storm had maximum sustained winds of 150 mph, up from 145 mph Sunday.

Perhaps most interesting of all is Rev. Gerry Seale's Update 4, of Sunday morning, which notes:

Dr. Jeff Masters at asked this morning: “Can Jamaica pray away Hurricane Dean? The official forecast and nearly all of the computer models have put Jamaica in the bulls-eye for several days now. But hurricanes have a funny way of taking 11th-hour wobbles that spare the island a direct hit. Witness the remarkable turn Hurricane Ivan took in 2004, as it headed directly for the island with 145 mph winds. Ivan took a sudden turn 35 miles from the island, traced out an exact outline of the island's coast 35 miles offshore, then resumed its previous track. In the Jamaica Observer, Custos of Kingston , Reverend Carmen Stewart, contends that it was not the first time that prayers had influenced the turn of events when disaster faced Jamaica . "It has happened time and time again," Reverend Stewart says. "I know people have been praying and I don't see any other reason why it (the hurricane) would make such a drastic turn.... God hears prayer.” ”

Our resounding response is, “Yes, God can.” As we have been praying the projected path of Hurricane Dean has moved to the south of Jamaica . The island will still be in a very serious situation in the next few hours as the worse winds tend to be in the north eastern quadrant of the storm and this quadrant will be impacting Jamaica . Please continue to pray.

And though the damage and several deaths [up to eight it seems] is a tragedy, things could have been much, much worse. However, I am deeply concerned to note from the AP report, indicators that in Jamaica many people seemed to ignore credible warnings of the serious hazards they were running from Dean:
. . . The government [of Jamaica] set up more than 1,000 shelters in converted schools, churches and the indoor national sports arena. Authorities urged people to take cover from the storm, which had maximum sustained winds of 145 mph and could dump up to 20 inches of rain.

But only 47 shelters were occupied as the storm moved in, said Cecil Bailey of the Office of Disaster Preparedness and Emergency Management. More people trickled in later.

George Lee, mayor of the Portmore community near the Jamaican capital Kingston, said appeals to evacuate went unheeded. Some islanders said they were afraid for their belongings if they moved to shelters.

Property, though painful to lose, can be replaced. Lives cannot -- and of course our Lord warns us that it is no profit to gain the whole world but at the expense of losing one's soul. So, let us put this all into perspective.

May God grant us all his grace, and now it is time to move on to the disaster response, recovery and sustainable rebuilding phases in Jamaica and Hispaniola, as in the Eastern Caribbean. END

No comments: