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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1824. jpsb
Quoting hunkerdown:
The second trough may or may not have any additional northerly influence on him...it should be the trough currently over the states that turns him away.
Yea, I was just wondering if I had all the pieces of the forecast right in my head. I've been watching that ull here http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?wv_east_enhanced+12 and noticed that it is not looking as vigorous as it did 2 days ago. Still should do the job of turning bill more to the north. Also the big trof over the eastern US has slowed a bit hopefully it will get over the east coast in time to carry bill away.
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Quoting hunkerdown:
The second trough may or may not have any additional northerly influence on him...it should be the trough currently over the states that turns him away.


Evening all. This shows the trough that Hunker is talking about thats supposed to turn Bill to the north. Hope it helps. :)


Link
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Quoting lurkn4yrs:



Wow..geez..thanks I already did that. That's why I was asking here so that I can get a better opinion from people with knowledge.

Robert Herbert stressed the point that not every hurricane that went through his hypothetical boxes hit Florida. Nevertheless he stressed that every storm that went through either box should be monitored closely.
Please out there, be my guest in correcting me if I'm wrong.
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1821. IKE
1817...I think the "benchmark" they refer to is 40N and 70W. Discussions in the NE USA reference that a lot in their discussions.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:


LOL...I was just thinking about that when I saw your avatar. Anxiously awaiting your new one....
I hope you are not holding your breath.
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Quoting 7544:


getting to close to bhamas now could he be taking the southern route of the nhc cone instead oihh lets hope he dosent ride that line
barring some unforeseen change, he is currently about as close to the Bahamian chain as he will get.
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1818. IKE
Quoting eyesontheweather:
BTW IKE, I am still looking for a new picture as discussed this morning...


LOL...I was just thinking about that when I saw your avatar. Anxiously awaiting your new one....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
This is from WHDH News Center 7 Boston:

Daily Weather BlogLast Updated on 08/19/2009 at 11:08pmBy Pete BouchardWell it's official. Despite being tickled by a sea breeze in the early afternoon, we made a mid-afternoon run for 90 and made it.


Heat wave status in Boston!


Already the temperatures are falling and the cooler air is coming in. This will last for a whole day before the muggy air comes roaring back on Friday.


Good news? Thunder is only "chancy" through Saturday. Bad news? It's all because the fronts and weather systems are waiting for Hurricane Bill to make his move. We don't need them to stop, we need them to move...Bill...outta here!


See this?






That's what is known as "the benchmark" in weather. If Bill goes to the left of that mark, he may hit hit us. If he goes to the right, we're just watching the surf and talking about what "mighta been".


It's as simple as that. Right now, the weather maps are sending him several hundred miles offshore. But there are a couple of outliers that send him right off of Chatham and Nantucket - and they weren't showing that scenario this morning or last night. If he doesn't make that last minute turn to the right Saturday night, he could sail right onto Cape Cod.


On this, the anniversary of Hurricane Bob (1991), we're on pins and needles.


(And as a matter of record, when the name Bob was retired in 1992, he was replaced with Bill.)


Surf's up!


Pete
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1816. 7544
Quoting Elena85Vet:
Bill now in the Northwest Atlantic sat imagery.





getting to close to bhamas now could he be taking the southern route of the nhc cone instead oihh lets hope he dosent ride that line
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1815. IKE
Quoting eyesontheweather:
Good evening Ike, All I have been keeping an eye on this track and been keeping a chart. Am just noticing (I am an amatuer) that Bill has never yet made it to a full 315* (NW). Since 08-18-09 at 7:00 am it has been on a course of 285* and since 6 pm central today has been on a course of 280*. This is based on points at time intervals on tracking map, not a moment by moment movement. It is all very interesting and in the end bill will go where he wants go(weather patterns take him) And might I add while models can and do change the accuracy becomes better each and every year.


True about it being south of a NW track the entire time. I think he's on a 305 track now.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
BTW IKE, I am still looking for a new picture as discussed this morning...
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1813. IKE
Quoting StSimonsIslandGAGuy:
The NHC should make their forecast based on what their information shows, period. If the models change to show a New England impact, they should show it and give people time to prepare. If the models show it staying further out to sea, they should show that. Speculation on economic effects should have no place in their forecasts. And I doubt such things play any role.


I can't recall them ever mentioning anything in any discussion about a USA hit. Not saying they've excluded the USA, just can't recall them mentioning them......yet.

They seem pretty sure on track.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:


Think it starts on the 0345UTC frame and ends at 0615UTC.
Good evening Ike, All I have been keeping an eye on this track and been keeping a chart. Am just noticing (I am an amatuer) that Bill has never yet made it to a full 315* (NW). Since 08-18-09 at 7:00 am it has been on a course of 285* and since 6 pm central today has been on a course of 280*. This is based on points at time intervals on tracking map, not a moment by moment movement. It is all very interesting and in the end bill will go where he wants go(weather patterns take him) And might I add while models can and do change the accuracy becomes better each and every year.
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Bill now in the Northwest Atlantic sat imagery.



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Looking @ post 1650(WV Loop of Bill).

1. Anybody else notice how clearly that offshore trough is showing up in the WV? Very cool.

2. Anybody else realize how far WEST Bill has to go to line up with the NHC track? The Wward jogs are not actually out of line with expectation. I'm not going to get "parrie" abt Wward motion unless it suddenly brings Bill well west of 65W before it crosses 25N. Anything else is business as usual.
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Quoting jpsb:
Am I correct? Bill has broken free of the first trof and will soon be interacting with the second trof? And this second trof is suppost to turn him more to the north. Is that correct, anyone? thanks.
The second trough may or may not have any additional northerly influence on him...it should be the trough currently over the states that turns him away.
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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.
Yes, that is how I do it. Is on WNW to NW track, about a 300 track. Definitely not due NW.
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Hopefully Bill will be nothing but a wave maker for the US, but if I was the NHC I would be very sure before releasing any information even hinting on a continental US landfall. The effects of just the "possibility" would cause consumer chaos, and spending. Its a loose win situation I guess.
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1805. jpsb
Quoting LoneStarWeather:
It looks like Bill's outflow on the NW quadrant is being disrupted a bit.
Am I correct? Bill has broken free of the first trof and will soon be interacting with the second trof? And this second trof is suppost to turn him more to the north. Is that correct, anyone? thanks.
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1804. 7544
best thing to do is too see where bill jumps afetr the blackout and during dmax will he jump west or nw untill then we have to wait but strange things happen at that time to systems
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WOW, Bill looks to be thinking of visiting NY. Glad its not coming to the Gulf.
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Quoting KerryInNOLA:
It IS a jog, and has lasted several frames. Whether it is temporary or a real trend only time will tell. Am waiting for blackout to end.
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.
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1801. IKE
Quoting KerryInNOLA:
It IS a jog, and has lasted several frames. Whether it is temporary or a real trend only time will tell. Am waiting for blackout to end.


Think it starts on the 0345UTC frame and ends at 0615UTC.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Evening, all.

REading abt the family members who may be out on the waters. Key idea here is LONG vacation. I don't see how u can condemn to death people who were boating off Nantucket at a time when Bill was 900 miles east of Antigua. However, I also doubt such people would be completely ignorant of the weather. Despite the harshness of its wording, I think press' advice was sound. The worried family members should attempt to connect the boaters, through the Coast Guard if necessary. I don't think the boaters are just out there, carefree, doing their thing. They may not be aware that their landbound family members are worried about them, though.

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Quoting centex:
How is fishing in NE?


I'm sorry if I was inconsiderate of your concerns, I'm leaning toward the east side of the track, but I could be wrong. If you are on the west side I hope I am correct and it goes east does not effect you. I believe the trough will be strong enough to take Bill out to sea. I only have best of wishes for all in saying Bill is going fishing.
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1798. IKE
Quoting lurkn4yrs:



Wow..geez..thanks I already did that. That's why I was asking here so that I can get a better opinion from people with knowledge.


Looks like Bill won't be going through one of those boxes and won't be hitting Florida. Mr Hebert's theory holds true for Bill.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
It IS a jog, and has lasted several frames. Whether it is temporary or a real trend only time will tell. Am waiting for blackout to end.
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It looks like Bill's outflow on the NW quadrant is being disrupted a bit.
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1794. IKE
Looks to me like he's just wobbling WNW and then wobbling back to the NW. Normal in strong systems. Impressive looking storm.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
It appears that there is movement to the west. More than just a wobble.
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The wave that is supposed to pull bill seems to be too far north. The wobble toward the west appears to me to be more of a jog to the west.
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1791. IKE
Quoting jsit:


But what do the results imply? looks like it splits up or something offshore new england and the models arent done past like 81 hours or so. Just looked wierd- I dont know what to make of that at all.


It just shows that some of the ensembles have Bill brushing northern New England, while most of the models keep him east of Maine, making landfall in Canada.

NHC is going with a Canadian landfall, right now. That is subject to change.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting HopquickSteve:
http://en.wikipedia.org/wiki/Hebert_box



Wow..geez..thanks I already did that. That's why I was asking here so that I can get a better opinion from people with knowledge.
Member Since: August 15, 2009 Posts: 0 Comments: 90
Quoting HopquickSteve:
Anywhere in Bos-wash, landfall would be horrible. I'm really glad that there is at least some curving.

Quoting HopquickSteve:
Anywhere in Bos-wash, landfall would be horrible. I'm really glad that there is at least some curving.

That swath of states houses 20 million plus people. The tri-state region(NY,NJ,Conn)is the home of 1 in 16 Americans. Catastrophic wouldn't even begin to describe what would happen
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1788. centex
Panic if it moves west of next forecast plot. So far so good but I would not bet my life on forecast track.
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1787. jsit
Quoting IKE:


Ensemble members of the GFS model and their forecast tracks....


But what do the results imply? looks like it splits up or something offshore new england and the models arent done past like 81 hours or so. Just looked wierd- I dont know what to make of that at all.
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Quoting lurkn4yrs:
Hey guys whats up with this Herbert Box theory I heard on here today..
http://www.hurricanecity.com/hebertbox.htm
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1785. IKE
Quoting jsit:
Can someone better with weather than I explain to me the GFS model data for new england on the wundermap? Not sure I get what it means so far as this Bill storm.


Ensemble members of the GFS model and their forecast tracks....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
check out this buoy reading.... significant wave height of 40ft, so swells peaking in upwards of 70ft plus
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Anywhere in Bos-wash, landfall would be horrible. I'm really glad that there is at least some curving.
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1782. jsit
Can someone better with weather than I explain to me the GFS model data for new england on the wundermap? Not sure I get what it means so far as this Bill storm.
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Quoting KerryInNOLA:
With models slowly moving west and Bill jogging west, I would keep my eyes open and car gassed up if I lived on Cape Cod.
Bill is not jogging west, he is and has been averaging almost a dead on NW track.
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1780. RJY
http://wattsupwiththat.com/

Want to know the real deal on climate change???? READ IT The best objective look on the topic of climate change I've ever seen. Educate yourself people don't listen to the media/talking heads.
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Hey guys. Has blackout started yet?
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http://en.wikipedia.org/wiki/Hebert_box
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With models slowly moving west and Bill jogging west, I would keep my eyes open and car gassed up if I lived on Cape Cod.
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Quoting Thundercloud01221991:


Wasn't it Hurricane on NOLA but they never showed it because 2 days before airing it Hurricane Katrina made landfall so they showed it 2 years later

Both you and Ike are correct. Yes 1,1 was NY, and there was the NOLA cat 5 scenario "what if" that sort of happened.
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1775. centex
Quoting washingaway:


Gone Fishing
How is fishing in NE?
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Hey guys whats up with this Herbert Box theory I heard on here today..
Member Since: August 15, 2009 Posts: 0 Comments: 90

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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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