Bill intensifies to Category 4; globe has 5th warmest July on record

By: Dr. Jeff Masters , 3:28 PM GMT on August 19, 2009

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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

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yah! it was the tool used to predict these events before computers and television. And has been known to very accurate! years back it was what a lot of folks lived by. they used the moon, stars and sun to predict events. just like the ocean sailors for tracking purposes. not trying to offend you but in some areas of the US it is still a trusted figure, unlike METs
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Quoting naplesdoppler:
Hello all, lurker for years and I do post once and a while. Not sure if it is new this year but I have never noticed it before. I understand obviously the H for Hurricane, S for Tropical Storm, and D for Depression, but what is M??? I know it is for winds 110 and higher but what is the reasoning behind the letter M?

Major
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1471. jdjnola
Ok I'm going to throw this out there and see if anyone has an opinion or some facts. We know that two tropical low pressure systems who approach each other can exhibit a Fujiwhara effect, but what about a low pressure trough (which is expected to push Bill N/NE) and a tropical low pressure system (aka Bill)? Is it possible that the approaching low pressure trough and Bill can exhibit the Fujiwhara effect and orbit each other in a cyclonic fashion?
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Models will should contnue to inch back to the West unfortunately.
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StormW, since this is my first time approaching your illustriousness, I ask that you forgive me.
Do you think by any figment of the imagination that the 18z GFDL is overdone? 165mph winds seems a bit overdone to me, but I hear the GFDL is more reliable compared to the HWRF? Thanks!
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Hello all, lurker for years and I do post once and a while. Not sure if it is new this year but I have never noticed it before. I understand obviously the H for Hurricane, S for Tropical Storm, and D for Depression, but what is M??? I know it is for winds 110 and higher but what is the reasoning behind the letter M?
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how far west will bill go?
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1466. Dakster
Quoting StSimonsIslandGAGuy:


Actually it's very simple. New Jersey is hundreds of miles west of the westernmost model track. And Bill will be moving at 30 kts and New Jersey will be on the weak left side of the storm. It's not rocket science. It's as easy as saying Texas will have no significant impact from Bill.

And I'm not that young, lol.


And you can rule out California too..
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I might have to ride down and watch some of those waves.

You might want to plan ahead. You might get caught up in evacuation traffic... 5 mph, bumper to bumper, no gas in the stations, everyone trying to get boats out of the water... what a zoo.

If you plan a way in to look at the waves, think about at least 2 good routes to get out if it hits the fan.
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Quoting MelbourneTom:
One more question for StormW or anyone willing. Thoughts on Cap Code this weekend. We have family there and can not get in touch with them. Found out they are on an extended weekend and may be on their boat.

Not a time to be on the water. This site shows expected wave activity.
https://www.fnmoc.navy.mil/ww3_cgi/cgi-bin/ww3_area.cgi?color=w&area=natl
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StormW, since this is my first time approaching your illustriousness, I ask that you forgive me.

By any figment of the imagination, do you think that the 18z GFDL is a little overdone? 165mph winds seems a little much for me, but I hear that it's the more reliable model compared to the HWRF? THANKS!
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goodnight and sweet dreams of nice places.
glad bill is cooperating with his track!
Hi JLPR, actually, there was mention of this in the 8 p.m. Discussion:
...TROPICAL WAVES...
A TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS EXTENDING FROM 15N22W TO 9N19W MOVING W NEAR 10 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE DERIVED WINDS ALSO INDICATE LOW/MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.
Also relieved there is nothing spinning up in the Gulf. So far so good!
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1461. JLPR
yep our wave train seems to have dissipated =P



They start to look weak inland and then they loose all convection when they hit water
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1445 - maybe the models finally took a gander at their own prediction for the slower frontal movement and that's why it's going west lol sometime i really hate the models especially during hurricane season. My personal feeling is a slight to moderate westward trend to the forecast is going to take shape.
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Quoting cajunkid:
medicroc, you might ask StormW about the models

Didn't want to bother. He's got his hands full with everyone else(he's always a gentleman and always accomodating. Don't want to take advantage).
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Thats what I have been saying and the NHC still stays with there track. But they wrote this in the discussion. I quote "IF THIS SOLUTION IS CORRECT...BILL WOULD BE ABLE TO MOVE A LITTLE
FARTHER TO THE WEST BEFORE TURNING TO THE NORTH AND NORTHEAST.
THERE HAS BEEN A SMALL WESTWARD SHIFT IN MOST OF THE AFTERNOON
MODEL GUIDANCE...AND THE OFFICIAL FORECAST IS SHIFTED IN THAT
DIRECTION. THIS IS A GOOD TIME TO POINT OUT THAT THERE IS A LOT OF
UNCERTAINTY IN THE LONG-RANGE TROPICAL CYCLONE FORECAST AND ONE
SHOULD NOT FOCUS ON THE EXACT TRACK AT THOSE TIME PERIODS.
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StormW...asked earlier..no one responded. Been outta loop for a while. Where is Nash?
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I might have to ride down and watch some of those waves. OBX isn't far at all... hour and half tops.
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medicroc, you might ask StormW about the models
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Going to be some rough surf in the Outer Banks for sure...heading down there this weekend.
Member Since: September 12, 2007 Posts: 0 Comments: 725
Quoting texascoastres:
For those concerned with the GOM. I do not know if you trust the Farmers Almanac, but it is predicting 2 hurricanes in the GOM this year. One around the 4th of september, the other around the 12th of september. Both to jack with Texas. They predicted one last year too! "IKE".
WOW! Farmer's Almanac!
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Going up...




Significant Wave Height



National Data Buoy Center
6-meter NOMAD buoy

21.652 N 58.695 W (2139'7" N 5841'42" W)
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Quoting Ossqss:
Wow, they just referenced 16-22' waves at the Outer banks in a few days on the TWC. That is ontop of the water level increase !

Big all the way up/down the coast.

Think I'm going to look for some webcams for this.
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1445. breald
It looks like the models are starting to cluster over New England. Not sure if this is a trend. I think the NHC will adjust their cone to cover more of Cape Cod at 11pm.
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One more question for StormW or anyone willing. Thoughts on Cap Code this weekend. We have family there and can not get in touch with them. Found out they are on an extended weekend and may be on their boat.
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Quoting cajunkid:
September 4th. I prob. should not have said anything...thats a looong way away

Hey, don't worry. As we say in NY "fuggetabouit":)
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anyway, glad that bad boy is behaving as predicted and staying offshore.
so far it's best case scenario.
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For those concerned with the GOM. I do not know if you trust the Farmers Almanac, but it is predicting 2 hurricanes in the GOM this year. One around the 4th of september, the other around the 12th of september. Both to jack with Texas. They predicted one last year too! "IKE".
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Quoting cajunkid:
go to maps on the home page and look at models

Link


Pardon if this sounds bizarre but is the nam on this link showing the trough breaking down or pulling back from the coast(trying to better learn how to read these models). Bill is looking uncomfortably close on this animation
Thank you
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maybe bill will remedy the inversion problem in the ne.
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am i the only person who thinks they are writing off this storm too early? Every model run I've seen lately has slowed the front from clearing the east coast, if this trend continued wouldnt that cause a western shift in the end result? Also noticed one model has now gone back to a southern New England landfall, but it has been inconsistant. A local example of this is this weekend was suppose to be nice here in Connecticut because the front was supposed to blow on through Friday.... now the front isn't supposed to clear until late sat or early sun. Also I noticed a couple of models now showing the hurricane "breaking free/through" the influence of this trough in the first place.... but I've been into the weather for two decades and I know not to trust the models too much.
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1434. Relix
@Kman: thanks for the quicksat. Doesn't seem like much going on there at the moment. Seems like the season will wind down for a while after Bill and wake up later.
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September 4th. I prob. should not have said anything...thats a looong way away
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1431. Ossqss
Wow, they just referenced 16-22' waves at the Outer banks in a few days on the TWC. That is ontop of the water level increase !

Big all the way up/down the coast.
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1430. snotly
Quoting hydrus:
Whats a cantori cam?


Cantore or Cantori how does he spell it?
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StSimonsIslandGAGuy,
I stand corrected...
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1427. Dakster
P451 - I happy it ISN'T happy... This is one of the things keeping it from becoming an Annular Hurricane, which would be "bad"...
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Quoting StormW:


Yes sir...take and move your cursor out to the left edge (blue area), and right click on your mouse.


Thanks, I will try it.
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Quoting hydrus:
Whats a cantori cam?
The "Cantori Cam" is Jim Cantori's personal camera.
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go to maps on the home page and look at models

Link

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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