Oil enters the Loop Current and is headed to the Florida Keys
Satellite imagery today from NASA's MODIS instrument confirms that a substantial tongue of oil has moved southeast from the Deepwater Horizon oil spill and entered the Gulf of Mexico's Loop Current. The Loop Current is an ocean current that transports warm Caribbean water through the Yucatan Channel between Cuba and Mexico. The current flows northward into the Gulf of Mexico, then loops southeastward just south of the Florida Keys (where it is called the Florida Current), and then along the west side of the western Bahamas. Here, the waters of the Loop Current flow northward along the U.S. coast and become the Gulf Stream. Once oil gets into the Loop Current, the 1 - 2 mph speed of the current should allow the oil to travel the 500 miles to the Florida Keys in 10 - 20 days. Portions of the Loop Current flow at speed up to 4 mph, so the transport could be just 4 - 5 days. It now appears likely that the first Florida beaches to see oil from the spill will be in the Lower Florida Keys, not in the Panhandle.
Figure 1. Satellite image of the oil spill taken at 12:40 EDT Monday May 17, 2010. The location of the Loop Current is superimposed. Image credit: University of Wisconsin and NASA.
Why is oil getting into the Loop Current?
The winds over the oil spill location are offshore out of the northwest today, and offshore winds will continue intermittently through Wednesday, which should allow a substantial amount of oil to enter the Loop Current. The major reason oil is moving southwards is because of the instability of the currents in the Gulf of Mexico. The Loop Current is not a stable feature, and tends to surge northwards and southwards in a chaotic fashion, and in response to changes in the prevailing winds. Over the past week, chaotic behavior of the Loop Current and a clockwise-rotating eddy just to its north, just south of the oil spill location, have combined to bring a current of southward-moving surface water to the oil spill location. As strong on-shore winds from the southeast slackened this past weekend, oil has been drawn southward into the Loop Current. The latest NOAA trajectory forecasts failed to anticipate the movement of the oil into the Loop Current. The latest surface current forecasts from NOAA's HYCOM model show that oil could continue pouring into the Loop Current for most of the rest of the week. It is highly uncertain how diluted the oil might get on its voyage to northwestern Cuba and the Florida Keys this week, but the possibility for a major ecological disaster in the fragile Keys ecosystem cannot be ruled out. Southeast to east winds of 10 - 15 knots are expected to develop late this week and extend into early next week, which may be strong enough to impose a surface current that will shut off the flow of oil into the Loop Current by Friday or Saturday.
Figure 2. Forecast made at 8pm EDT Sunday May 16, 2010, of the Gulf of Mexico currents by NOAA's HYCOM model. A persistent southward flowing surface current is predicted to occur this week between the oil spill location (red dot) and the Loop Current. Image credit: NOAA.
Likely areas of impact
Based on a study of 194 floating probes released into the Northeast Gulf of Mexico during a 1-year study in the 1990s (Figure 3), the west coast of Florida from Tampa Bay southwards to the Everglades is at minimal risk of receiving oil from surface currents. There is a "forbidden zone" off the southwest Florida coast where the shape of the coast, bottom configuration, and prevailing winds all act to create upwelling and surface currents that tend to take water away from the coast. This study implies that the greatest risk of land impacts by surface oil caught in the Loop Current is along the ocean side of the Florida Keys, and along the coast of Southeast Florida from Miami to West Palm Beach. Eddies breaking away from the Gulf Stream would also likely bring oil to northwest Cuba, the western Bahamas, and the U.S. East Coast as far north as Cape Hatteras, North Carolina, though at lesser concentrations. Southwest Florida cannot rest entirely, though--the "forbidden zone" is only true for surface waters, and there is onshore flow below the surface. Since recent ship measurements have detected substantial plumes of oil beneath the surface, southwest Florida might be at risk if one of these plumes gets entrained into the Loop Current. These subsurface plumes were also detected by current probes launched into the oil spill on May 8 by one of NOAA's hurricane hunter aircraft, according to one scientist I spoke to at last week's AMS hurricane conference. There are plans for the Hurricane Hunters to go out again tomorrow and drop more probes into the spill to attempt to get a better handle on where the oil is and where the currents are taking it.
Figure 3. Paths of 194 floating probes released into the yellow-outlined area in the northeast Gulf of Mexico between February 1996 and February 1997 as part of a study by the Mineral Management Service (MMS). The probes were all launched into waters with depth between 20 and 60 meters. Image credit: Yang, H., R.H. Weisberga, P.P. Niilerb, W. Sturgesc, and W. Johnson, 1999, Lagrangian circulation and forbidden zone on the West Florida Shelf, Continental Shelf Research Volume 19, Issue 9, July 1999, Pages 1221-1245 doi:10.1016/S0278-4343(99)00021-7
When will a Loop Current eddy break off?
Every 6 - 11 months, the looped portion of the Loop Current cuts off into a clockwise-rotating ring of water that then slowly drifts west-southwest towards Texas. When one of these rings breaks off at the peak of hurricane season, it provides a source of heat energy capable of providing fuel for rapid intensification of any hurricanes that might cross over. The Loop Current is not predicted to shed an ring over the next month, as predicted by the latest 1-month forecast from the U.S. Navy. However, the last eddy broke off in July of 2009, ten month ago, and it is unusual for the Loop Current to go more than eleven months without shedding an eddy. I expect we'll see the Loop Current shed an eddy in July or August, just in time to pose the maximum threat for hurricane season. According to an interesting February 2004 article published by offshore-engineer.com, reliable forecasts of these currents and eddies are not available yet. Keep in mind that surface currents are largely driven by winds, and wind forecasts are not reliable out more than about 10 days.
References
Yang, H., R.H. Weisberga, P.P. Niilerb, W. Sturgesc, and W. Johnson, 1999, Lagrangian circulation and forbidden zone on the West Florida Shelf, Continental Shelf Research Volume 19, Issue 9, July 1999, Pages 1221-1245 doi:10.1016/S0278-4343(99)00021-7.
Oil spill resources
NOAA trajectory forecasts
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Surface current forecasts from NOAA's HYCOM model
HYCOM ocean current forecasts from LSU
Jeff Masters
Reader Comments
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Subtropical systems do not have to be asymmetrical. They can be symmetrical too, and often the ones that actually get named do have a certain degree of symmetry. It's something they need to have to develop barotropically.
The phase diagram shows it being symmetrical warm-core but when you go to the vertical profile it shows it being shallow, which still puts it as subtropical.
There are a few things wrong with this:
First, lower than normal pressures, the MJO and warm ssts is more than unstable
Second, the Coriolis parameter is never a problem in the SW Caribbean, afterall, this is a vorticity riched environment.
I live over in Orange and we haven't had any significant rain since March until Saturday. My garden is green and growing thanks to the irrigation system.
Yes as the GFS shows, but then it slowly creeps it north towards death.
LINK
MJO FORECAST CONTINUES TO SUPPORT IDEAS ON POSSIBLE EARLY SEASON DEVELOPMENT
http://www.cpc.noaa.gov/products/precip/CWlink/MJO/gfs.gif
The powerful upward motion forecast for day 10 indicates we could have a named storm on the charts for the Memorial Day weekend. Of course last year there is a righteous argument that the storm that hit Dauphin Island Friday night of Memorial Day weekend should have been named, and it's something I can't argue against. But in this case, it appears the ideas I have had on the possible early start to the season do have some merit, as the modeling is seeing the kind of pattern that would do it.
Our first hint is what is going on south of Asia with a cyclone to hit India later this week and another storm likely to form off the eastern tip of Africa, but indicative of the active monsoonal circulation that means a stronger African wave train this year.
In the meantime, mayhem tomorrow morning over southeastern New England may be a problem as fully leaved trees with 2-4 inches of wind driven rain may come down on Nantucket and the Cape. Let's not put the cart before the (sea) horse as far as influences go.
Wow, what a classic Memorial Day week is shaping up, a heat wave develops and the tropics may come to life.
by joe
hi all.
Jeff I'm not sure if anyone believes it will threaten the US, they just think it has a better chance to develop than the ATL disturbance. It will have a decent 3-4 day window before it moves too far north.
The four columns read from top to bottom:
Analysis
5 Day forecast
10 Day forecast
15 Day forecast
The 10 day forecast shows very strong upward motion over the Gulf, Caribbean and Atlantic. This is around Memorial Day Weekend.
Since I haven't posted in awhile here is a bit about me. Some of you may remember me, I have been posting here in the tropical season since 2006. I am a Senior in High School and am attending Millersville University in PA for Meteorology in August. I am a frequent poster on EasternUSWX and attending a conference on June 6th in Baltimore with Bill Read as a guest speaker. (very excited). And I recently shelled out a good amount of dough (for me at least) for a GR2AE copy, so you will be seeing those images as things come ashore, and I am also amateur photographer.
Salazar: Gov't failed to assure drilling safety
Interior Secretary Ken Salazar caught sharp criticism from lawmakers Tuesday over the government's failures in overseeing offshore oil drilling, and he acknowledged his department had been lax in holding industry accountable.
by The Associated Press
wwltv.com
Posted on May 18, 2010 at 11:36 AM
See all 6 photos »
NEW ORLEANS -- Federal officials say they're expanding the area of the Gulf of Mexico where fishing is shut down because of a massive oil spill.
They had already shut down fishing from the Mississippi River to the Florida Panhandle soon after an offshore oil rig exploded and sank last month. About 7 percent of federal waters were affected.
The National Oceanic and Atmospheric Administration announced Tuesday that it's expanding the closed area, though it won't say exactly where until later in the day. Nearly 46,000 square miles, or about 19 percent of federal waters, will be shut under the expanded ban.
Dr. Jane Lubchenco of NOAA says the government will be testing fish that is caught to make sure it's safe.
(Copyright 2010 by The Associated Press. All Rights Reserved.)
I like to read what he says. He thinks longer range and is usually correct.
NEW 12Z
Discount the track, but the same area...
No
Were all gonna need a bigger room .
The better chance of tropical development is the Caribbean feature, not forgetting the possible hybrid low.
man, that thing looks like a black light poster I had back in '69
so the carib TS is still a possibility? Wouldn't it be odd if we had simultaneous May cyclones that would be a first
becoming a more real possibility with each model runs.
6:52 PM GMT on May 18, 2010
See my blog, Tampa is in the "Forbidden Zone" where very little surface transport of water towards the coast occurs. So unless one of the slow moving deep water plumes of oil gets close, you are probably safe.
Jeff Masters
Tropical Cyclone Advisory NUMBER EIGHT
CYCLONIC STORM LAILA (BOB01-2010)
17:30 PM IST May 18 2010
====================================
Subject: Cyclonic Storm LAILA over southwest and adjoining west central Bay of Bengal:
Cyclone Warning (Orange message)
At 12:00 PM UTC, Cyclonic Storm Laila over southwest and adjoining southeast Bay of Bengal moved west northwest and lays centered over southwest and adjoining west central Bay of Bengal near 13.0N 83.5E, or about 350 kms east of Chennai, 520 kms south of Visakhapatnam, and 1200 kms south southwest of Kolkata.
3 minute sustained winds near the center is 45 knots with a central pressure of 990 hPa. The state of the sea is high around the system's center.
Satellite imagery indicates banding pattern of the system. The intensity of the system is T3.0. Associated broken intense to very intense convection observed over the Bay of Bengal between 8.0 to 17.5N. The lowest cloud top temperature due to convection is around -90C in association with the sytsem.
Vertical wind shear of horizontal wind over the region is low (5-10 knots). The system lies to the south of tropospheric ridge, which roughly runs along 15.0N. System is under the influence of anticyclonic circulation located to the northeast of system. It is likely to guide the system northwest to northward after some time. Shear tendency over the past 24 hours is negative to the north of the system. The relative vorticity at 850 HPA level and upper level divergence are also favorable for intensification, as they increased during the past 12 hours.
Considering all the above and numerical weather prediction model guidances, the system is likely to intensify further and move in a west northwesterly direction then move northwesterly to northerly direction and cross Andhra Predesh coast between Ongole and Visakhapatnam by early Thursday.
Forecast and Intensity
=========================
24 HRS: 15.0N 81.5E - 65 knots (Very Severe Cyclonic Storm)
48 HRS: 17.5N 82.0E - 50 knots (Severe Cyclonic Storm)
72 HRS: 19.5N 84.5E - 40 knots (Cyclonic Storm)
lol
The CMC and the GGEM are the same model.
May 14, 2010:
May 17, 2010:
Pretty substantial difference in just 3 days time.
I bet you still have it
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