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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Quoting weathersp:


Hey look I'm on that map.... crap.


Welcome to the club!

I'm going to take a break and come back later.

New mantra for today:

"West, North, West, North, Wobble, Wobble."
repeat 3x and breathe
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thanks, I thought I was looking at it right. Just wanted to double check myself.
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Quoting K8eCane:


i'm about a mile from the one in wrightsboro
where in nc did u live?
Lived in Greensboro, on the Piedmont, back before Hugo came to visit. It was really startling a few years later to visit places like Charlotte and Raleigh and find gaping places where venerable old trees had been....
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721. A4Guy
Quoting TheCaneWhisperer:


August 19th. It is current and accurate.


Sorry...it's updated now. I swear when you first posted it was 8-17 - I triple checked. Maybe I had an issue with my PC showing me an old cached version, somehow??
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Quoting TexasHurricane:
I noticed a concern at the end of this in the GOM...Is there anything else out there that shows this as well? (I know all these aren't 100% accurate - just wondering if anything else may be hinting at a potential problem in GOM, coming up)



yea I was looking at that too.... that would be too soon to be the new wave developing.
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Model performance thus far for Bill...


http://hurricane.methaz.org/tracking/storms/AL032009_model_perf.html
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.
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Quoting TheCaneWhisperer:
It will be tough to get them to budge with the LGEM following their track. They may bend it a little left to account for the TCVN though.


Agree with the TVCN. LGEM follows their track because it is their track (interpolated). LGEM is an intensity model using the same track as SHIPS.
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I think the simplest way to see the trough is in the jet stream maps. The big dip in the jet in the center of the US is the longwave trough.

WU jet stream map
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HurricaneCavalier: Anything useful to say? At all? Then why are you posting?
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Quoting HurricaneCavalier:


Ah, so you confirm? Sweet. Time to change my tunic and pantaloons and slip into some high cut jean shorts and a faded AC/DC t-shirt.



AC-DC?...

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Quoting seminolesfan:
Baby chickens...on a weather blog... Nothing here surprises me anymore so, sure, why not!
I'd have thought a farm, or even the front yard of certain Cayman Islanders' residences, might have been a more effective place to look, myself.
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Quoting cajunmoma:
can someone tell me where the trough that Dr. Master's speaks of is located now? TIA


Is currently developing... but you can see it on the W CONUS...

Link

If you put it in motion... you'll see the trough amplifying southward. Coming down from the US NW region (Idaho, etc...) and getting down to Texas.

You can also see it in this other link (shown in the red coloring):

Link
Member Since: August 14, 2008 Posts: 4 Comments: 5029
Quoting cajunmoma:
can someone tell me where the trough that Dr. Master's speaks of is located now? TIA


Midwest into Manitoba.

US Water Vapor Loop
Member Since: January 14, 2007 Posts: 17 Comments: 4140
Quoting klaatuborada:


"One man's garbage is another man's treasure"

unless of course, you're a racoon.


LOL, I like you...you're funny
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Quoting A4Guy:
673 - your SFWMD map is from August 17!!!!!


August 19th. It is current and accurate.
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I noticed a concern at the end of this in the GOM...Is there anything else out there that shows this as well? (I know all these aren't 100% accurate - just wondering if anything else may be hinting at a potential problem in GOM, coming up)

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Quoting Crawls:


It has nothing to do with being a snob. It has everything to do with trying to learn a few things and weeding through the garbage.


"One man's garbage is another man's treasure"

unless of course, you're a racoon.
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Quoting cajunmoma:
can someone tell me where the trough that Dr. Master's speaks of is located now? TIA
The strong trough is the one near the Dakotas currently. The one further east is progged to wash out.
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Quoting TheCaneWhisperer:
It will be tough to get them to budge with the LGEM following their track. They may bend it a little left to account for the TCVN though.


I say they will keep the track as is. This shifting has been happening for as long as I have been following.
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Quoting BahaHurican:
Ah, Food Lion..... those were the days.....

U know no hurricanes hit NC or SC the entire 3 years I was living in NC????

LOL



i'm about a mile from the one in wrightsboro
where in nc did u live?
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Quoting cajunmoma:
can someone tell me where the trough that Dr. Master's speaks of is located now? TIA


You can see it progress by looking at the HPC 7 day surface forecast loop.
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NHC will shift west at 5PM...Things are getting interesting again, after our collective dissapointment with it missing Florida ;)





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Quoting nrtiwlnvragn:


I think NHC will shift left somewhat, but not a lot at least on the next advisory. Just as the models have been shifting west, they could begin to shift east again. If they maintain a lefward bias, the NHC will follow in that direction.


Agree, tad left IMO They tend to follow the two I mentioned below.
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I really hope there is no NY landfall.
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696. Prgal
Quoting cajunmoma:
can someone tell me where the trough that Dr. Master's speaks of is located now? TIA

I think you can see it here: http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?wv_east_enhanced+12
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695. A4Guy
673 - your SFWMD map is from August 17!!!!!
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First Ana death? Rip tide killed a 73 yr old man trying to save his grand kids here in East NC.
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Quoting reedzone:
Again, my forecast does NOT make landfall in the USA. It's a straight up good forecast for right now, but if trends continue showing a weaker trough pulling more northward in Canada, I might have to nudge it more to the left unfortunately.
Hey reed, right now I'm liking the NHC forecast. HOwever, that hasn't stopped from keeping a beady eye on Bill. Too many storms have come our way from that general vicinity over the years for me to feel completely comfortable .... I like leelee's aproach - grill a little of that fresh meat u have in the house, savour the sunset, stuff like that. LOL
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Bill going by Hurricane Hole:
Link
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I think the Hurricane Center will shift west to be in the middle of the guidance envelope at 5 pm. My thinking is Bill will ride along the coast, and not make an official landfall. Jim Cantore headed to Nantucket Island to cover Bill?
Member Since: June 29, 2009 Posts: 13 Comments: 5315
Bill seems to fight pretty much with the shear infront and seems to loose some substance to the north. He is still away from the 29C. warm SST's.
And he is a little north of the forcasted track, shown here: Caribbean - Water Vapor Loop
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It will be tough to get them to budge with the LGEM following their track. They may bend it a little left to account for the TCVN though.
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Quoting cajunmoma:
can someone tell me where the trough that Dr. Master's speaks of is located now? TIA


In the Midwest...some areas near Kansas City have received over 10" of rain this week from this trough.
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Quoting TheCaneWhisperer:
Looks like the NHC is becoming east of the guidance envelope.



I think NHC will shift left somewhat, but not a lot at least on the next advisory. Just as the models have been shifting west, they could begin to shift east again. If they maintain a lefward bias, the NHC will follow in that direction.
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can someone tell me where the trough that Dr. Master's speaks of is located now? TIA
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Quoting HurricaneCavalier:


Ah, so you confirm? Sweet. Time to change my tunic and pantaloons and slip into some high cut jean shorts and a faded AC/DC t-shirt.

I don't know...there is quite a tropical feel here...some white slacks and a flowered shirt might be needed.
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Quoting weathersp:


Hey look I'm on that map.... crap.


Everyone in the NE should watch Bill... even if it is unlikely to hit. Tracks change... even the high probability ones
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Quoting HurricaneCavalier:


Yeah most snobs have extensive hate lists.


You don't have to be a snob to have lots of people on ignore. A few just ask for it. Also, JFYI, "ignore" is not the same as "hate" by a long way. Oh, POOF, BTW!
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Quoting centrfla:
frances in 04 is approximately at the same place as bill is now (19.0 56.8)...what makes the difference in their forecast track????
The presence or absence of a trough. Lots of other storms have passed through those coordinates over the years. The bulk of them have been turned by troughs. The rest of them, like Frances and Ike, become the storms we warn our children with.....
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Quoting Orcasystems:


Landfall locations.. NY is in play


How come this map won't load for me?
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676. Prgal
I think we are all entitled to have an opinion. But at the end, the people in the NHC are the ones making the calls and they are doing a great job. I trust the 3-day cone because its highly accurate but not the 5-day cone. PR was in the cone for a few days and nothing happened (glad it didn't).

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Quoting Crawls:


It has nothing to do with being a snob. It has everything to do with trying to learn a few things and weeding through the garbage.


Thanks, crawls...you are exactly right
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I am thinking that the NHC has been dead on so far !!
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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.