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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Not been posting here much lately, but have to come out of work/lurk mode for this one!

Floodman! Great to see ya!
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Even though we (in Trinidad) are out of Bill's path, friends in Toco just reported some pretty rough waters to the North-East of the island. The Stone Walls are taking a beating. But other than that, its pretty good weather.
Member Since: August 18, 2009 Posts: 0 Comments: 201
reed, what do you think about this path? I made it at 9 am. I definitely should have included Bermuda in the cone, but follow the center line....what do you think?
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Quoting rwdobson:
@262, just asking b/c someone said the NAM re-develops Ana. From what I know about NAM it is especially bad for formation because it has issues with convective feedback...creates a lot of storms that never happen.


Correct
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269. IKE
Quoting apocalyps2:
From DR Masters"
its still not clear when Bill is going to turn"
For me it is clear for days.Bill will turn friday.


It's quite clear you are a west-caster.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting futuremet:


The 12Z GFS expects a mid level high to develop and steer a tropical cyclone toward the east coast. It also tries to develop a quasi-permanent troughing pattern over the east coast for the next two weeks, which would likely curve any TCs out to sea. The ECMWF has been showing an analogous pattern, but has been eroding the trough over the past runs..


And when do they expect this Tropical Cyclone to steer near the East Coast?
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Ok time for advice

i'm here in wilmington nc (cape fear) and i'm watching Bill. the local forcasters are all over it too. They are basically saying we are clear from a direct hit but are not ruling out tropical storm conditions just yet. What say ye??
Member Since: April 26, 2006 Posts: 5 Comments: 3098
263. IKE


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
1054 AM EDT WED AUG 19 2009

.UPDATE...
THE COVERAGE OF SHOWERS AND THUNDERSTORMS HAS BEEN MUCH LESS THAN
ORIGINALLY ANTICIPATED -- ESPECIALLY ACROSS THE SOUTHWESTERN
HALF OF THE FORECAST AREA. IT APPEARS THAT A LOW-LEVEL INVERSION
SEEN IN THE 12Z MFL RAOB AND LIMITED DIURNAL HEATING BENEATH A
BROAD CIRRUS DECK ARE BOTH RESPONSIBLE FOR THIS. HOWEVER...PWAT
VALUES DO REMAIN VERY HIGH...EVEN FOR LATE AUGUST...AND WITH A
MID-LEVEL TROUGH IN THE VICINITY OF SOUTH FLORIDA AND POTENTIAL
FOR ADDITIONAL WARMING THIS AFTERNOON...AM RELUCTANT TO LOWER POPS
BELOW 60 PERCENT. THIS CHANGE WILL BE NOTED IN FORTHCOMING ZFPMFL
PRODUCT.
Member Since: September 23, 2005 Posts: 14 Comments: 11059
@262, just asking b/c someone said the NAM re-develops Ana. From what I know about NAM it is especially bad for formation because it has issues with convective feedback...creates a lot of storms that never happen.
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263. IKE
Here's the forecast this afternoon for Miami....

"Rest of Today
Mostly cloudy with showers and thunderstorms likely. Breezy. Locally heavy rainfall possible. Highs around 90. Southeast winds 15 to 20 mph decreasing to 10 to 15 mph later in the afternoon. Chance of rain 60 percent."


Here's their current conditions....

"Miami, Florida (Airport)
Updated: 31 min 31 sec ago
Mostly Cloudy
87 °F
Mostly Cloudy
Humidity: 69%
Dew Point: 76 °F
Wind: 13 mph from the ESE
Pressure: 30.06 in (Steady)
Heat Index: 97 °F
Visibility: 10.0 miles
UV: 8 out of 16
Clouds:
Scattered Clouds 2500 ft
Mostly Cloudy 14000 ft
(Above Ground Level)
Elevation: 7 ft".....


Here's their radar........WTH?

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting rwdobson:
Correct me if I'm wrong, but I don't think the NAM can be trusted at all to predict whether something develops or not...


The majority of the models had a mediocre performance so far this year. I recommend using the ECMWF
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IF other models trend towards NOGAPS, GFS, and CMC, The NHC western part of the 5 day cone might cover the eastern end of Long Island, NY.
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Correct me if I'm wrong, but I don't think the NAM can be trusted at all to predict whether something develops or not...
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Quoting TampaSpin:
We need to watch this spin at 24N 84W NAM has it developing i do believe it old ANA.




Yep.... and on Long Range radar from Key West, you can make out some slight rotation. Nothing even strong yet but thunderstorms are building (slightly). Something to watch today but it would have to really blow up and soon to be a player (or anything for that matter).

Link
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I'm still predicting that Bill will skirt the New England coastline and effect Canada.. This has been my thinking since Sunday.
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Quoting TampaSpin:
We need to watch this spin at 24N 84W NAM has it developing i do believe it old ANA.



Well crap. Thanks for the heads up Tim.
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Gulf is a little different too, since "fish storm" isn't really an option when it gets to the gulf...

anyway, i think people in the northeastern US should certainly not consider themselves in the clear yet. florida is safe, despite apoclyps' best efforts.
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Quoting WxLogic:
One interesting thing to note with GFS... it is trying to forecast another IKE type HURR... this year is certainly proving to be quite interesting with quite a bit of dynamics happening every week and sometimes unusual.


The 12Z GFS expects a mid level high to develop and steer a tropical cyclone toward the east coast. It also tries to develop a quasi-permanent troughing pattern over the east coast for the next two weeks, which would likely curve any TCs out to sea. The ECMWF has been showing an analogous pattern, but has been eroding the trough over the past runs..
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252. IKE
Latest GFS...CMC and NOGAPS are about the same, showing Bill crossing just SE of Maine.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Weather456:
Good Afternoon

Hurricane Bill complete update



Nice update 456!
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Quoting apocalyps2:
That through will be late and much more to the north.
That allows Bill to go longer to the West.


Don't I know you from somewhere?
Quoting katzanddogz:



Opps. LOL Had that experience happen just last week! LOL


Sorry to hear that...pk's and gauze I take it? That's what I got when I heard that dreadful phrase
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Quoting DestinJeff:


ok, New Orleans on the west / Tampa to the east .... either way, the point is residents along the northern Gulf Coast wouldn't be told ALL CLEAR, /em>


wow, thats a very good point. something to think about anyway.
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Quoting Floodman:


No worries...I'm more concerned with Stormw's "crap"...kind of like being in the dentists chair with his hands in your mouth and he says "Uh oh"...typically nothing good comes from it



Opps. LOL Had that experience happen just last week! LOL
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"-- about 200 miles from Destin to Biloxi by car (not sure as the Crow flies)"

wow, guess it's been too long since I was in the area...need to go back and see my cousin at his beach house in Mary Esther...
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Quoting TampaSpin:
We need to watch this spin at 24N 84W NAM has it developing i do believe it old ANA.



Interesting, Tampa

I made my first blog a little bit ago comments would be appreciated
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Good Afternoon

Hurricane Bill complete update

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Quoting SomeRandomTexan:


True the "P" word can do that.. lol! good to see you on!

You know, the trolls got angry about that and had me banned for a weekend last year. Now I just stay silent about certain individuals and ignore them without any foofooraw; easier that way and I don't have to monitor the blog as a guest
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242. IKE
Quoting WxLogic:


Hehe... is basically taking the possible Tropical Disturbance Doc just mentioned and having it miss the trough that is currently forecasted to affect Bill and then be driven SW by a developing High behind it.

Check the 12ZGFS and you'll see the similarities.


I looked at the 12Z GFS. I see a low that crosses that Atlantic that winds up east of the USA at 384 hours, never affecting any land(like Ike).
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting SomeRandomTexan:


Speaking of glowing in the dark... we actually had that happen after Gustav, down by the pass, baitfish and mud that was stirred up would actually glow. They said it was a phenomenon caused from algae. PA beaches aren't all that nice, good for fishing though, especially for sharks and reds!
There is an oceanic alga Noctaluca that shows up occasionally in the shore waves. It is phosphorescent and has a pleasant "watermelon" like odor. Nothing like the unpleasant Gymnodinium organism that causes occasional red tides!
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Quoting Floodman:


No worries...I'm more concerned with Stormw's "crap"...kind of like being in the dentists chair with his hands in your mouth and he says "Uh oh"...typically nothing good comes from it
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.
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@234

That's in a bad spot too...
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Quoting PortABeachBum:
35 years in the same house. Keep the insurance paid up and hope it's all still when I get back from evac. And we do evacuate, well in advance, and every time!


By the way, I like your avatar...my dad was in Inchon in the early 50s...he wasn't leaving the port though; he and his luggage were heading inland LOL
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We need to watch this spin at 24N 84W NAM has it developing i do believe its old ANA.

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Quoting Floodman:


Don;'t say poof, brother...gets you in trouble around here...LOL. Just trying to peal the virus out of the bosses PC and keeping up with the weather


True the "P" word can do that.. lol! good to see you on!
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I was wondering if BILL is becoming annular. This evening, I have seen an algorithm to determinate it... Can anyone say something about it?

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"For comparison .... a gulf coast resident (Destin, for example) would NEVER let guard down if a storm had NHC track at 5 days in Appalachiacola, or Biloxi".

That's not really a very good analogy. Destin is, what, 100 miles from Biloxi? Destin would be well inside the cone if the 5-day track had the landfall at Biloxi or Appalachicola.

And most people on here would say that Cape Cod does need to keep an eye on Bill...I sure would.
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Quoting PortABeachBum:
35 years in the same house. Keep the insurance paid up and hope it's all still when I get back from evac. And we do evacuate, well in advance, and every time!


I like it down there, and after this year so do my sister and brother in law...quiet peaceful little place with decent beaches...what part of town you in?
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90/96 hour point not looking too good on 12Z CMC.

Edit - about bang on with the 12Z GFS that someone noted in an earlier post.
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Quoting atmoaggie:

You didn't possibly think that anyone would have the word beach in their handle and be from Port Arthur, did ya, FloodMan? (Well, I did, once) Port Arthur's "beach" isn't somewhere one would want to be often or for very long...unless you want to glow in the dark.


Speaking of glowing in the dark... we actually had that happen after Gustav, down by the pass, baitfish and mud that was stirred up would actually glow. They said it was a phenomenon caused from algae. PA beaches aren't all that nice, good for fishing though, especially for sharks and reds!
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226. 7544
Quoting IKE:
Here's the 12Z NOGAPS.

Notice the vorticity with Bill mainly stays just south and east of Maine....by then it will be in colder waters and a shearing system...


whats that behind bill tia
Member Since: May 6, 2007 Posts: 0 Comments: 6751
Quoting WxLogic:
One interesting thing to note with GFS... it is trying to forecast another IKE type HURR... this year is certainly proving to be quite interesting with quite a bit of dynamics happening every week and sometimes unusual.


link?
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Hey Atmo-

Does the modeled MJO cause the enhanced tropical thunderstorm activity (and cyclones) or do the cyclones themselves cause the signal in the 200hPa divergence???

Especially with the models, you get the chicken or the egg conundrum...

My understanding was that a TRUE MJO pulse emanated from the very strong convection in the Indian Ocean/Indonesia region and "reverberated" around the globe generally moving easterly like a wave.

The signal we seen in the 200hPa anomalies often seem more of a locally enhanced event
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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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