Bill intensifies to Category 4; globe has 5th warmest July on record
Category 4 Hurricane Bill is now the the fourth strongest tropical cyclone to appear on the planet so far this year, and may grow even stronger. Visible and infrared satellite imagery continue to show an impressive, well-organized, hurricane, with plenty of low-level spiral banding and upper-level outflow well-established on all sides except the west. On Bill's west side, upper-level winds from the west are creating a modest 10 knots of wind shear, which is giving the hurricane a bit of a squashed appearance there.
Wind shear is forecast to remain low to moderate, 5-15 knots, for the next four days. Sea Surface Temperatures (SSTs) will rise steadily from 28.5°C today to 29°C on Friday. Total ocean heat content is at a maximum today, and will gradually decline over the next four days. Bill should be able to take advantage of these favorable conditions a remain a major hurricane the next three days.
Figure 1. Visible satellite image from NASA's Aqua spacecraft at 12:40pm EDT Tuesday August 18, 2009. Image credit: NASA GSFC.
Water vapor satellite loops show a small "short-wave" trough of low pressure to the north-northwest of Bill, and this trough has turned Bill on a more northwesterly track over the past two days. Bill will miss the Lesser Antilles Islands, and the main impact of the hurricane on these islands will be high waves. The short wave trough (so called because it has a relatively small amplitude and wavelength) is not strong enough to turn Bill due north, and Bill is also expected to miss Bermuda. High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.
Figure 2. Visible satellite image of Bill's eye zoomed in, taken from NASA's Aqua spacecraft at 12:40pm EDT Tuesday August 18, 2009. Image credit: NASA GSFC.
An unusually strong "long wave" trough of low pressure (called long wave because of its large amplitude and wavelength) is expected to develop along the U.S. East Coast late this week. This trough will turn Bill to the north, and also bring high levels of wind shear in the 40 - 65 knot range on Sunday. Exactly where this turn occurs is still not clear. The models continue to be in two camps: an eastern camp (GFS, GFDL, HWRF, and ECMWF) that takes Bill 300 - 500 miles east of Cape Cod, and a more western camp (NOGAPS, UKMET) that bring Bill within 150 - 200 miles of Cape Cod. Both sets of models bring Bill ashore over the Canadian provinces of Newfoundland or Nova Scotia. Bill will be weakening rapidly as it makes landfall, and is likely to be a Category 1 hurricane if it hits Nova Scotia, or strong tropical storm if it hits Newfoundland.
Bill's big waves
Large swells from Bill will begin impacting the U.S. East coast from Florida to Maine beginning Friday night or Saturday morning. Seas will build to 5 - 10 feet in the offshore waters from central Florida northwards to South Carolina, and to 10 - 15 feet from North Carolina to Cape Cod. Near shore, waves will be about 40% less. This will cause a significant coastal erosion event along some portions of the coast. The latest run of the NOAA Wavewatch III model suggests that significant wave heights near Bill's center will reach 50 feet on Sunday. Since maximum wave height is typically about a factor of 1.9 greater than the significant wave height (which is the average trough-to-crest height of the top 1/3 largest waves), a few huge waves near Bill's center may reach 95 feet high.
Possible impacts to New England
The current set of computer model runs predicts that the center of Bill will pass Cape Cod, Massachusetts Sunday afternoon or evening. Tropical storm-force sustained winds of 39 mph or greater currently extend out 185 miles to the west of Bill's center, so that if Bill maintains its current wind distribution, Cape Cod could see sustained winds of about 40 mph Sunday night if the models predicting a more westerly path are correct. However, Bill will not keep this same radius of winds. The hurricane will weaken considerably beginning Sunday morning, once the storm gets caught up in the approaching long wave trough. High wind shear of 40 - 65 knots due to strong southwesterly winds aloft will act to compress the hurricane in the east-west direction, keeping the hurricane's strongest winds away from Cape Cod. The highest winds are likely to be no more than 30 mph on Cape Cod from Bill, if the storm follows the track of the western camp of models nearest to the Massachusetts. A few rain squalls may affect coastal Massachusetts, but the main impact of Bill on New England is likely to be coastal erosion from high waves.
Elsewhere in the tropics
The remains of Tropical Storm Ana are bringing scattered heavy rain showers to the Bahamas and Florida today. The remains are disorganized, and are not likely to re-develop. The only model calling for a new tropical cyclone to develop in the Atlantic over the next seven days is the GFS model, which predicts development off the coast of Africa about 7 days from now.
Fifth warmest July on record globally; a cold July in the U.S.
The globe recorded its fifth warmest July since record keeping began in 1880, according to NOAA's National Climatic Data Center. NOAA rated the period January - July 2009 as the sixth warmest such period on record. NASA's Goddard Institute for Space Studies rated July 2009 as the 2nd warmest July on record, behind July of 1998. For the second month in a row, global ocean Sea Surface Temperatures (SSTs) in July were the warmest on record, 0.59°C (1.06°F) above the 20th century average. This broke the previous July record set in 1998. The record July SSTs were due in part to an ongoing El Niño event in the Eastern Pacific, which has substantially warmed a large stretch of the tropical Eastern Pacific Ocean. As El Niño conditions mature during the coming months, near-record global ocean and land temperatures will probably continue. Now that El Niño conditions have been well-established for three months, the atmosphere has begun to heat up in response. It typically takes up to seven months for the atmosphere to heat up in response to ocean heating from an El Niño. This may explain why June of 2009, which independent assessments by NOAA, NASA, and the UK Hadley center agreed was the 2nd or 3rd warmest June on record at the surface, recorded only average satellite-measured temperatures in the lower atmosphere. In contrast, the July satellite-measured temperatures in the lower atmosphere were the 2nd or 3rd warmest on record, in agreement with the assessments that surface temperatures were the 2nd to 5th warmest on record.
Figure 3. Departure of temperature from average for July 2009. Image credit: NOAA/NCDC.
A cold July for the U.S.
For the contiguous U.S., the average July temperature of 23.1°C (73.5°F) was the coolest since 1994, and July temperatures were the 27th coolest in the 115-year record, according to the National Climatic Data Center. Ohio, Illinois, Indiana, Pennsylvania, Iowa, and West Virginia experienced their coolest ever July. Kentucky, Missouri, Michigan, and Wisconsin recorded their second coolest July in history. A strong trough of low pressure parked itself over the eastern portion of the U.S. in July, funneling down plenty of cold air from Canada. In the western U.S., a ridge of high pressure dominated, bringing unusually hot conditions. Arizona recorded its 3rd warmest July on record, and Seattle, Washington recorded its hottest day in history on July 28, notching a 103°F reading. This was 3°F above the previous record set in 1994.
U.S. precipitation was near average in July, with the month ranking 40th wettest in the 115-year record. U.S. tornado activity was above average in July, according to NOAA's Storm Prediction Center. However, no tornado deaths occurred in July.
At the end of July, 14% of the contiguous United States was in moderate-to-exceptional drought. This is a drop from the 19% figure observed at the beginning of the year. These extreme drought regions were exclusively in South and Central Texas.
I'll have an update Thursday morning.
Jeff Masters
Reader Comments
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AMEN! I think I've found the first person to go on my list this year.
Good morning, y'all :)
isnt that the bahamas
I am originally from Long Island. You are not the first person to mention evacuating the NY area. I am here to tell you, there is no possibility of evacuating Long Island, for example, and even the island of Manhattan (between the mainland and Long Island) is a huge stretch. There are far too many people and far too few bridges and tunnels off of these two islands. My opinion is that it would take weeks to evacuate, not days.
Having said that, on Long Island, we have been through hurricanes before, because of how it sticks out off the east coast (south of Connecticut, etc.) though not often and nothing as major as a Cat 3 or 4. Still Long Island, geographically, is a BIG island, and not all of it is coastline. I imagine that evacuations would be similar to how they are done in Pinellas County in Florida where I now live, which is a peninsula, smaller than the size of Long Island. The barrier islands and coastline would be evacuated, and those folks would move inland, or in the case of Long Island it's probably more accurate to say that they would pull more into the center of the island.
I was at college in Upstate NY in 1985, when Gloria hit Long Island (where my folks and my sister still lived) with 85 mph winds and a forward speed of 35mph--combined winds of about 120mph if you do the math. They were without power or phones for over a week. But they survived, and the house survived. There was never any concept of evacuation. On a good day, without major traffic, it would have taken my parents 2 hours to get "off of" Long Island. They would have been in stopped traffic, stuck in their cars when the hurricane hit, if there was any attempt at evacuation. It's simply not feasible.
Thanks,i always wanted to be on youre list.
What do you think about Bill?Since youre seem to be so smart.Or are you afraid to tell youre opinion?
At least i dear to give mine.
No hard feelings.Amen.
I understand what you are saying. I just NEVER want to see a repeat of what happened in NO. That was a mess. When Gustav came last year they put into effect Contraflow...and it seem to work really well. I guess having gone through so many of these things, it just scares me to think of all the people and no where to go. Take Ike for instance, it just skirted us and we still got really high winds inland here in Louisiana. The surge is a big threat as well, I don't think anyone really expected Ike to have such huge surge with it. It would just be nice if it were some way to get people out of harms way.
2007. P451 11:32 AM GMT on August 20, 2009 Hide this comment.
Quoting hunkerdown:
don't analyse every satellite update, click the lat/long tab and look at the average track over the whole loop...you will see a NW track.
With Bermuda being equivalent to a needle in a haystack, every jog does make a big difference. It looks like it is going to jog again to the right of the track this morning. All those jogs bring the storm closer and closer and a jog of a mere 50 miles could have HUGE ramifications on the small island. I think people who pick enjoy it and are merely here to cause problems instead of study the weather. NHC is for sure studying every jog to see if it corrects itself or if the track may need to be adjusted to accommodate. Study away I say and for those that don't like it, simply move on to the next post.
Hello and Good Evening/Morning all.
1 question, Why isn't Typhoon Vamco listed as a Super Typhoon? Isn't Cat 4 Cat 5 normally classified as a Super Typhoon?
Cheers AussieStorm
Don't let them bother you. It is relevant and interesting. If we ignore the current things happening, we would only need to post every 6 hours on the updates and it is sure does break up the monotony :)
You are right, of course. It scares me a bit too--should have put that in my first post! My family still lives on Long Island, near the north shore, but not that close to the coast. Obviously, the north shore doesn't get it as bad as the south shore since the land mass would likely slow Bill down considerably.
If all goes well with the current track, they won't feel more than some gusty winds...but it is something I am keeping my eye on, because it would simply be a monumental task--in my opinion impossible--to evacuate that many people when there are only a few ways off of the island.
Lol...True!!
A true NW track would mean he travelled the same distance west as north. Most of his track has been roughly WNW, which means 2 miles west for each mile north.
Im just hoping Bill stays away...far far away!!
Back to Basic Definitions Page | Back to Main FAQ Page
Subject: A3) What is a super-typhoon? What is a major hurricane ? What is an intense hurricane ?
Contributed by Stan Goldenberg
"Super-typhoon" is a term utilized by the U.S. Joint Typhoon Warning Center for typhoons that reach maximum sustained 1-minute surface winds of at least 65 m/s (130 kt, 150 mph). This is the equivalent of a strong Saffir-Simpson category 4 or category 5 hurricane in the Atlantic basin or a category 5 severe tropical cyclone in the Australian basin.
"Major hurricane" is a term utilized by the National Hurricane Center for hurricanes that reach maximum sustained 1-minute surface winds of at least 50 m/s (96 kt, 111 mph). This is the equivalent of category 3, 4 and 5 on the Saffir-Simpson scale.
"Intense hurricane" is an unofficial term , but is often used in the scientific literature. It is the same as "major hurricane".
Amen to that!!
No....at least 300 miles east of NC.....
They still like the CV potential.
thats what i was looking for was the actual miles
local mets aint even saying the actual miles
again thank you
Anyway - I am writing now to voice irritation with a newscaster on tv today. After reading everything y'all have said - and how nothing is ever certain, this weather person blew off Bill with absolute certainty.
"Good news! Bill is an exciting storm - I like a good hurricane - but everyone is in the clear. It's going to miss the Bahamas, the East coast -" blah blah blah -- but she presented it as a "for sure."
Irritating.
Indeed and add a more western track to all models.Today Bill is going WNW.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
658 AM EDT THU AUG 20 2009
.SYNOPSIS...
BERMUDA HIGH PRESSURE REMAINS NEARLY STATIONARY OFF THE SOUTHEAST
UNITED STATES COAST THROUGH FRIDAY. A SLOW MOVING FRONTAL BOUNDARY
WILL APPROACH THE AREA FROM THE WEST FRIDAY NIGHT...THEN PUSH ACROSS
THE AREA SATURDAY INTO SUNDAY. HURRICANE BILL WILL PASS SEVERAL
HUNDRED MILES EAST OF THE MID ATLANTIC COAST LATE SATURDAY THROUGH
SUNDAY.
Just like Hurricane Jeanne was surely going out to sea. The models were in great agreement on that until the pesky NoGaps picked up on the loop.
I have a business trip set up for this weekend in NY and Boston, my question, should i cancel my trip or proceed? and what percentage of striking that area now?
And the eye is shrinking.Putting his act together.
Great graphic.
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