CSU predicts highly active hurricane season; Cyclone Phet approaching Oman
A very active Atlantic hurricane season is on tap for 2010, according to the seasonal hurricane forecast issued June 2 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 18 named storms, 10 hurricanes, and 5 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 185% of average. Between 1950 - 2000, the average season had 10 named storms, 6 hurricanes, and 2 intense hurricanes. But since 1995, the beginning of an active hurricane period in the Atlantic, we've averaged 14 named storms, 8 hurricanes, and 4 intense hurricanes per year. The new forecast is a step up from their April forecast, which called for 15 named storms, 8 hurricanes, and 4 intense hurricanes. The new forecast calls for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (51% chance, 31% chance is average) and the Gulf Coast (50% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also high, at 65% (42% is average.) This is the most aggressive early June forecast ever issued by the CSU group; the previous most aggressive such forecasts were for the 2006 and 2007 seasons, when the CSU team predicted 17 named storms, 9 hurricanes, and 5 intense hurricanes. Both of these forecasts did poorly, particularly the 2006 forecast, as only 10 named storms, 5 hurricanes, and 2 intense hurricanes were observed.
The forecasters cited four main reasons for an active season:
1) Weak La Niña conditions should develop by the most active portion of this year's hurricane season (August-October). The expected trend towards weak La Niña conditions should lead to reduced levels of vertical wind shear compared with what was witnessed in 2009.
2) Current SST anomalies are running at near-record warm levels. These very warm waters are associated with dynamic and thermodynamic factors that are very conducive for an active Atlantic hurricane season.
3) A weaker-than-normal Azores High prevailed during April-May. Weaker high pressure typically results in weaker trade winds that are commonly associated with more active hurricane seasons.
4) We are in the midst of a multi-decadal era of major hurricane activity, which began in 1995. Major hurricanes cause 80-85 percent of normalized hurricane damage.
Analogue years
The CSU team picked four previous years when atmospheric and oceanic conditions were similar to what we are seeing this year: weak El Niño to neutral conditions, well above-average tropical Atlantic SSTs, and above-average far North Atlantic SSTs during April - May. Those four years were 2005, the worst hurricane season of all time; 1969, the 3rd worst hurricane season of all time, featuring Category 5 Hurricane Camille which hit Mississippi; 1966, a relatively average year that featured Category 4 Inez that killed 1,000 people in Haiti; and 1958, a severe season with 5 major hurricanes. The mean activity for these five years was 17 named storms, 10 hurricanes, and 5 intense hurricanes, almost the same as the 2009 CSU forecast.
How accurate are the June forecasts?
The June forecasts by the CSU team over the past 12 years have had a skill 19% - 30% higher than a "no-skill" climatology forecast for number of named storms, number of hurricanes, and the ACE index (Figure 1). This is a decent amount of skill for a seasonal forecast, and these June forecasts can be useful to businesses such as the insurance industry and oil and gas industry that need to make bets on how active the coming hurricane season will be. Unfortunately, the CSU June 1 forecasts do poorly at forecasting the number of major hurricanes (only 3% skill), and major hurricanes are what do 80 - 85% of all hurricane damage (normalized to current population and wealth levels.) This year's June forecast uses the same formula as the past two years, which did quite well predicting the 2008 hurricane season (prediction: 15 named storms, 8 hurricanes, 4 intense hurricanes; observed: 16 named storms, 8 hurricanes, 5 intense hurricanes) and 2009 hurricane season (prediction: 11 named storms, 5 hurricanes, 2 intense hurricanes; observed: 9 named storms, 3 hurricanes, 2 intense hurricanes.) An Excel spreadsheet of their forecast skill (expressed as a mathematical correlation coefficient) show values from 0.44 to 0.58 for their June forecasts, which is respectable.
Figure 1. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 1999-2009 (May) and 1998-2009 (August), using the Mean Squared Error. The British firm Tropical Storm Risk (TSR) will issue their outlook for the 2010 Atlantic hurricane season on June 4. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.
NOAA's 2010 hurricane season forecast
NOAA issued their forecast for the upcoming Atlantic hurricane season last week. As I discussed in my post on their forecast, NOAA is calling for very active and possibly hyperactive season. They give an 85% chance of an above-normal season, a 10% chance of a near-normal season, and just a 5% chance of a below-normal season. NOAA predicts a 70% chance that there will be 14 - 23 named storms, 8 - 14 hurricanes, and 3 - 7 major hurricanes, with an Accumulated Cyclone Energy (ACE) in the 155% - 270% of normal range. If we take the midpoint of these numbers, NOAA is calling for 18.5 named storms, 11 hurricanes, 5 major hurricanes, and an ACE index 210% of normal. A season with an ACE index over 175% is considered "hyperactive."
Figure 2. Visible satellite image of Tropical Cyclone Phet on Thursday, June 3, 2010.
Tropical Cyclone Phet the 2nd strongest Arabian Sea storm on record
Record heat over southern Asia in May has helped heat up the Arabian Sea to 2°C above normal, and the exceptionally warm SSTs helped fuel Tropical Cyclone Phet into the second strongest tropical cyclone ever recorded in the Arabian Sea. Phet peaked at Category 4 strength with 145 mph winds yesterday, and has weakened slightly to 135 mph winds this morning. Only Category 5 Cyclone Gonu of 2007, which devastated Oman, was a stronger Arabian Sea cyclone.
Phet is over very warm waters of 30 - 31°C, and is under moderate wind shear of 10 - 20 knots. However, the storm is wrapping in dry air from the Arabian Peninsula, which has caused weakening. Visible satellite imagery from this morning (Figure 2) shows that the heavy thunderstorms on the north side of Phet have been eroded away by dry air. Phet is a small storm, and could fall apart fairly quickly if dry air can penetrate into its core. This should happen later today, since wind shear is on the increase, and the shearing winds should be able to disrupt the circulation enough that dry air can force its way into Phet's eyewall. Phet is fairly small, will miss the most heavily populated areas of Oman, and will likely undergo significant weakening before landfall, so the storm is unlikely to cause the kind of catastrophic flooding that Category 5 Cyclone Gonu of 2007 brought to Oman. Gonu killed 50 people and did $4.2 billion in damage. Phet's heaviest rains will be confined to a relatively sparsely populated region of Oman's coast. Rainfall amounts in excess of 6 inches in 18 hours (Figure 3) can be expected along Oman's coast today, which will likely cause extreme flooding.
After Phet's encounter with Oman, the storm will probably be at tropical storm strength when it makes its second landfall in Pakistan. Heavy rains from Phet will be the major danger for Pakistan, and serious flooding can be expected over southern Pakistan.
Figure 3. Forecast rain amounts for the 18-hour period ending at 2am EDT June 3, 2010. Image credit: NOAA/NESDIS.
Oil spill update
Onshore winds out of the south, southwest, or west are expected to blow over the northern Gulf of Mexico over most of the next week, resulting increased threats of oil to Alabama, Mississippi, and the Florida Panhandle, according to the latest trajectory forecasts from the State of Louisiana. The latest ocean current forecasts from the NOAA HYCOM model show that these winds will generate a 0.5 - 1 mph current flowing from west to east along the Florida Panhandle coast Sunday and Monday. If this current develops as predicted, it will be capable of bringing light amounts of oil as far east as Fort Walton Beach, Florida, by Monday. If you spot oil, send in your report to http://www.gulfcoastspill.com/, whose mission is to help the Gulf Coast recovery by creating a daily record of the oil spill.
Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
My post Wednesday with answers to some of the common questions I get about the spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami
I'll be back Friday with an analysis of the new TSR hurricane forecast and a new forecast by a promising Florida State University model.
Jeff Masters
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 — Blog Index
It really is quite cool-looking. I am impressed at how much vorticity it has stacked from the surface all the way up to 500mb.
I don't normally use the NAM for forecasting out beyond 24 hours but, it was right on yesterday with a mini storm in the GOM possibly
Repost - this was directed at 536. Hurricane Junky - the quote feature did not work ... sorry.
If you are using Firefox with Adblock Plus you can right mouse the image and block it directly. The image will be replaced with a white block. - take care
I dont think i've ever seen a vertically stacked upper low before!? i was wondering why we were getting the low level winds of a circulation
I think that they assume they can get a tight enough seal, to prevent water getting in, and also (more important) to prevent the gasses from expanding in a large enclosed box (like the Dome they first put down)
Once they can get the stuff up the pipe to the surface, they can frac out the gasses and flare them off.
At least, this is how I read it.
A methanol Loop is in the Unit and that may,..may, prevent the Hydrates from Forming.
Its a big if though.
Nice!
AN UPPER LOW ALONG THE TEXAS AND LOUISIANA COAST WILL BE
WOBBLING OVER SOUTHERN LOUISIANA AND THE NORTHERN GULF OF MEXICO
THROUGH THE WEEKEND. THIS SYSTEM WILL KEEP THE CHANCE FOR SHOWERS
AND THUNDERSTORMS ONGOING...ESPECIALLY FOR LOCATIONS ALONG AND TO
THE SOUTHEAST OF AN EL DORADO ARKANSAS...TO SHREVEPORT AND BOSSIER
CITY LOUISIANA...AND TYLER TEXAS LINE. THE STRONGER STORMS
WILL BE CAPABLE OF PRODUCING WIND GUSTS OF 35 TO 45 MPH...HAIL
UP TO THE SIZE OF DIMES...DEADLY LIGHTNING...AND LOCALLY
HEAVY RAINFALL...WITH AMOUNT OF NEAR ONE INCH PER HOUR. DISCRETE
SEVERE THUNDERSTORMS WILL BE POSSIBLE...PRODUCING LARGE HAIL AND HIGH
AND DAMAGING WINDS. THERE MAY BE SOME PONDING OF WATER IN STREETS...
LOW LYING AND POOR DRAINAGE AREAS DUE TO RECENT HEAVY RAINS.
.SPOTTER INFORMATION STATEMENT...
ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND EMERGENCY
MANAGEMENT PERSONNEL IS NOT EXPECTED THIS AFTERNOON OR
TONIGHT.
$$
That small section of the choke/kill pipe which was welded to the side of the riser is cut off.
can work or
not work
does not
matter
the damage
is done
LOL....
Vertically-stacked lows occur every day. All it is is the upper low stacked on top of the surface circulation.
There is a surface low because strong MCCs can sometimes form their own surface circulation through inflow and upward motion, which causes low pressure beneath them. At this point they become an MCV, which is what this system did last night. The circulation often remains for a day or so afterward, and can spark thunderstorms near it the next afternoon. They can get quite nasty....the one over Illinois last year looked like a tropical cyclone.
Yeah, the restrictions in the BOP are still slowing the flow. GOOD!
True, I forgot that.
Tropical Storm Allison - June 4-18, 2001
A tropical wave moved off the west coast of Africa on May 21st. Tracking westward, it moved
through the tropical Atlantic and Caribbean Sea...reaching the eastern Pacific Ocean on June 1st.
A low level circulation formed on the 3rd south of Vera Cruz, and this system moved north into
southeast Mexico steered by deep southwest flow. It emerged into the Bay of Campeche on the
4th as an area of thunderstorms, and guided north-northwest through the western Gulf of Mexico.
The low became increasingly organized, and when reconnaisance aircraft investigated the system
on the 5th, it had already become a tropical storm about 80 miles south of Galveston Texas. As it
was steered by the subtropical ridge off the southeast, Allison moved north into Texas that evening,
eventually tracking as far inland as Lufkin by the morning of the 7th. After already dropping ten or
more inches of rain across portions of Texas and Louisiana, the cyclone began to move southward as
a ridge over New Mexico strengthened just as the high off the southeast flattened and moved southeast.
This set the stage for massive flooding in southeast Texas on on the 7th and 8th. The highest totals
noted were 36.99 inches at the Port of Houston Texas, and 29.86 inches at Thibodaux Louisiana.
Portions of Houston, Beaumont, Thibodaux, Lafayette, New Orleans, and Baton Rouge saw severe
flooding from all this rain. Rains would continue into the 11th, as Allison moved back off the Texas
coast, paralleling the coast of Louisiana before making a second landfall in the Teche region of the
Bayou State.
Reintensifying over land as it tracked through southeast Louisiana and southwest Mississippi,
Allison formed an eye feature during the morning of the 11th, a rare accomplishment for a tropical
cyclone over land. The system moved swiftly east-northeast crossing southern Mississippi and
Alabama, central Georgia, and South Carolina, being steered by the subtropical jet stream to its
north.
Motion slowed as it approached a blocking ridge of high pressure off the coast of New
England, which then allowed the cyclone to move northward along the coast of the Mid Atlantic
and just offshore New England from the 16th through the 18th. Significant floods occurred in
northeast North Carolina and southeast Pennsylvania during this time frame, with areas measuring
10 inches of rain within 6-12 hours. The last of the heavy rains with Allison escaped off the
Eastern Seaboard during the early morning hours of the 18th.
Damages as of this writing are estimated at $5 billion...with over $4 billion in the state of Texas.
This makes Allison the most costly tropical cyclone in Texas history. Its track lies below.
To date Allison is the ONLY Tropical Storm to have its name retired.
i think i'm done for today
It does matter, the damage will get worse!
THAR SHE BLOWS
incredible video of uninterupted Horrors.........
Looks like a good southerly flow to the lows east...bad news for oil-haters along the northern gulf coast.
There is a google earth file for the flight, once opened need to click "non-tasked mission" on the left.
It's gone! Now, cap the son of a gun, why don't ya...
not really
at this point
it's a matter of
relatively minor
degrees
Well she appears to have formed from a disturbance coming NW off the Yucatan. Are you thinking of when she finally came back over water after sitting over Texas for days?
What feed are you watching?
Yeah that isn't gonna be good. :(
Well.....
THAR SHE BLOWS
incredible video of uninterupted Horrors.........
what did I miss??!!
CNN Website. They have several feeds.
Those must be old....i have the live feeds up....
I step away for one second and miss all the action.
CNN feeds have gone away from the outflow at the BOP now
They change around from time to time. I am sure when they start with the cap, they will be live there.
Viewing: 601 - 651
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 — Blog Index