Hurricane Omar Threads the Needle


Hurricane Omar IR Satellite 1016 1515Z

Hurricane Omar IR Satellite 1016 1515Z

Hurricane Omar Forecast Track 1016 11AM

Hurricane Omar Forecast Track 1016 11AM

Hurricane Omar moved quickly through the northern Antilles….the Northern Leeward Islands…and did so in a quite pleasing manner. I had explained late Wednesday that the storm was on the upswing and that was potentially bad news. As it went through the islands, the pressure was down to about 961mb and the winds up to 125 mph. But, the center of the storm where the strongest winds are located, passed between St. Croix in the US Virgin Islands and St. Martin. St. Croix was on the left hand side of the storm and while, when you read this report, it says that the island was on the “weak side” of the storm. That weak/strong point is well known for a landfalling hurricane. But, when you are talking about a storm in open waters perhaps passing over small islands, I don’t think that weak side/strong side formula holds much veracity. As it was, the US Virgin Islands were far enough away from the center that the winds were around 50 mph.

Hurricane Omar Vis Satellite 1016 1515Z

Hurricane Omar Vis Satellite 1016 1515Z

I have learned something new though…that is that one of the 10 largest oil refineries is on St. Croix. Authorities there shut down the Hovensa oil refinery as a precaution. Apparently Hess got together with the US Virgin Islands government to diversify the economy. Now, the refinery is situated in a spot where it can make finished products and then send them up the east coast or into the Gulf of Mexico or even up the Missisippi River to the US Interior. Its the largest employer in St. Croix. I wonder if the products from the refinery that end up in the US are considered imports…and anything that goes to another country considered to be an export? I guess I’m not up to speed on what degree the US Virgin Islands are considered part of the US.

Anyway, as I had mentioned in the previous post, Omar is moving rapidly and will move even more quickly as it goes into the North Central Atlantic where it has already begun to diminish and will continue to do so as it moves into much colder water. In all honesty, the satellite imagery looks pretty ragged on midday Thursday and it looks like this guy is getting ripped up very quickly. This storm passed through the islands at the very height of its life…the folks on the islands are fortunate that they didn’t get a direct hit and that Omar was good at threading needles.

HURRICANE OMAR DISCUSSION NUMBER 13

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152008

1100 AM EDT THU OCT 16 2008

Hurricane Omar Spaghetti Model 1016 12Z

Hurricane Omar Spaghetti Model 1016 12Z

IT IS SIMPLY AMAZING TO ME AT HOW QUICKLY A HURRICANE CAN SPIN UP AND JUST AS QUICKLY FALL APART. OMAR REACHED NEAR THE THRESHOLD OF CATEGORY 4 EARLY THIS MORNING AROUND 06Z AND NOW WE HAVE AN EXPOSED LOW-LEVEL CENTER SHOWING UP IN THE VISIBLE SATELLITE IMAGERY JUST A FEW HOURS LATER. SUBJECTIVE AND OBJECTIVE DVORAK TECHNIQUES WERE SUGGESTING AROUND 90-100 KT AT 12Z. BUT GIVEN THE RAPID DETERIORATION OF THE CONVECTIVE SIGNATURE…THE CURRENT INTENSITY IS ESTIMATED…WITH SIGNIFICANT UNCERTAINTY…TO BE 75 KT. DESPITE VERY WARM WATERS…THE COMBINATION OF STRONG VERTICAL SHEAR AND LOW TO MID-LEVEL DRY AIR…AS SEEN IN THE TOTAL PRECIPITABLE WATER IMAGERY…HAS PRODUCED THE WEAKENING IN OMAR AND WILL LIKELY CONTINUE TO CAUSE A DECREASE IN ITS INTENSITY. BECAUSE THE

Hurricane Omar Spaghetti Model Intensity Graph 1016 12Z

Hurricane Omar Spaghetti Model Intensity Graph 1016 12Z

TREND OF OMAR’S INTENSITY WAS NOT CORRECTLY ANALYZED AT SYNOPTIC TIME…THE STATISTICAL MODELS…SHIPS AND LGEM…ARE PROVIDING VALUES THAT ARE PROBABLY TOO HIGH. THE FORECAST IS CLOSEST TO THE HWRF MODEL WHICH DID VERY WELL IN ANTICIPATING THIS MORNING’S RAPID WEAKENING OF OMAR. AS THE CYCLONE BECOMES EXTRATROPICAL AROUND DAY 4…IT DOES NOT APPEAR THAT SIGNIFICANT RE-INTENSIFICATION WILL TAKE PLACE AT THAT TIME BASED UPON THE GLOBAL MODELS’ CONSENSUS. THE NOW EASY-TO-SEE CENTER DID FORCE US TO MAKE A LAST SECOND RELOCATION OF THE INITIAL POSITION AS WELL AS THE SHORT TERM TRACK FORECAST TO ACCOUNT FOR THE MORE SOUTHERN LOCATION THAN AT FIRST ESTIMATED. THE TRACK GUIDANCE IS CLOSELY CLUSTERED THROUGH 72 HR…BUT THEN SHOWS SIGNIFICANT DIVERGENCE AT DAYS 4 AND 5. THE TRACK FORECAST IS A BLEND OF THE FASTER CONSENSUS OF THE GLOBAL AND HURRICANE MODELS AND THE SLOWER PREVIOUS ADVISORY.

FORECAST POSITIONS AND MAX WINDS

INITIAL 16/1500Z 20.2N 61.3W 75 KT

12HR VT 17/0000Z 23.5N 59.5W 70 KT

24HR VT 17/1200Z 28.0N 56.9W 65 KT

36HR VT 18/0000Z 31.3N 54.3W 60 KT

48HR VT 18/1200Z 33.4N 51.9W 55 KT

72HR VT 19/1200Z 38.0N 45.0W 55 KT

96HR VT 20/1200Z 40.0N 34.5W 50 KT…EXTRATROPICAL

120HR VT 21/1200Z 40.0N 23.0W 40 KT…EXTRATROPICAL

$$ FORECASTER LANDSEA/STEWART

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