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

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

Share this Blog
2
+

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

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1924 - 1874

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46Blog Index

Night Tampa. Thanks for your input.
Member Since: Posts: Comments:
I agree with Tampa on this, it maybe only temporary but the first trough has defiantly been knockout to the n.e. , the real question is will the next trough flatten out, and to what extent. All this has a direct influence on where this storm will go.Models have been pretty accurate so far remember they were not that accurate earlier.
Member Since: Posts: Comments:
Nite everyone ! I'm beat....Bill go north PLEASE!
Member Since: Posts: Comments:
I will put all this to rest I think as all the air rushes toward the center it forms a spiral similar to your tube. The difference being it only has on way to go up, not down. But in the center of the eye all air is rushing up in the eye wall creating a vacuum which cause air to rush down in the eye itself causing low pressure. This is hard to see as the air coming into the eye quickly absorbs the air descending in the eye wall. Possible solution to a hurricane would be how to stop the air from descending in the eye its self.
Member Since: Posts: Comments:
But the problem i have if there is one......is the High off the East coast has gotten larger causing the trough to move further North than models are showing........Don't know if im right or wrong its just what i see.
Member Since: Posts: Comments:
Quoting floridiancanuck:
Is the term "extra tropical" used just to designate that a storm has left the tropics or do these storms somehow behave any differently further north?

Thanks. I've been greatly enjoying reading this blog these past few nights working the graveyard shift. =)


"Extra-tropical" means a tropical cyclone has lost its tropical characteristics. Instead of operating like a typical tropical system, the storm operates as if it's a normal low-pressure system. This happens after a tropical system has weakened considerable due to in being away from the favorable conditions of 80°-plus water and low wind sheer for a long time, usually several days.
Member Since: Posts: Comments:
Quoting canuckmom:
So Tampa, I think you are on the ball when it comes to this stuff, what's your latest take on Bill? Do you think he might keep nudging his way west before the turn? I love there aren't many on to flame me now. Besides, I have not vested interest; just curiousity.


The High that Bill moves up the West side of is just moving off the East Coast. The trough is suppose to erode the West Side of the High and allow Bill to scuddle up the Left side or the west side of the HIGH!

Member Since: Posts: Comments:
Quoting jpsb:
thanks, very nice! So all the air is rising particularly when it gets close to the eye as well as swirling around the eye. I got it, thanks again.


Your welcome! Thats a great Video and very easy to understand....which is what i need.....LOL
Member Since: Posts: Comments:
So Tampa, I think you are on the ball when it comes to this stuff, what's your latest take on Bill? Do you think he might keep nudging his way west before the turn? I love there aren't many on to flame me now. Besides, I have not vested interest; just curiousity.
Member Since: Posts: Comments:
1915. kabloie
Quoting 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.


Interesting enough. And as far as I can tell, untouched by total maniacs. Or, untouched compared to most climate blogs.

Thanks.
Member Since: Posts: Comments:
Quoting gordydunnot:
And I will say also nice blog site Tampa. Goodnight all, we will still be here tomorrow god willing and the creek dose not rise.


Nite.
Member Since: Posts: Comments:
And I will say also nice blog site Tampa. Goodnight all, we will still be here tomorrow god willing and the creek dose not rise.
Member Since: Posts: Comments:
1911. jpsb
Quoting TampaSpin:


DAM! I got everything....LOL! Here is your answer in a video on my site!
thanks, very nice! So all the air is rising particularly when it gets close to the eye as well as swirling around the eye. I got it, thanks again.
Member Since: Posts: Comments:
Quoting Sharkseatmore:


I thought air went in the top of the eye and was spun out the bottom... hence the surface winds


Nope. The eye is the exhaust.
Member Since: Posts: Comments:
Quoting canuckmom:
Okay, it's not showing up when I use my quote button, so I'll have to be more elaborate.

Tampaspin, I've been following this, the WU blog for about three years now and hadn't realized what an awesome blog you have! Well done! I'm totally impressed. I'll have to check it all out tomorrow!


Thanks so much for the kind words.....There is a lot there. As one person put it, I could spend a whole day in one place.........LOL
Member Since: Posts: Comments:
Okay, it's not showing up when I use my quote button, so I'll have to be more elaborate.

Tampaspin, I've been following this, the WU blog for about three years now and hadn't realized what an awesome blog you have! Well done! I'm totally impressed. I'll have to check it all out tomorrow!
Member Since: Posts: Comments:
Quoting Elena85Vet:
Actually the eye is the vent like a chimney.


I thought air went in the top of the eye and was spun out the bottom... hence the surface winds
Member Since: Posts: Comments:
Actually the eye is the vent like a chimney.
Member Since: Posts: Comments:
The NHC probably has tools we cannt imagine, and I am not going x-files on you. The only possible advantage we could have is more eyes. But for sure I would go with the NHC.
Member Since: Posts: Comments:
Quoting canuckmom:
So while I'm at it, if I'm gonna get banned, I really like your NovaFloridian accent! ROFL


Thanks, eh!
Member Since: Posts: Comments:
Is the term "extra tropical" used just to designate that a storm has left the tropics or do these storms somehow behave any differently further north?

Thanks. I've been greatly enjoying reading this blog these past few nights working the graveyard shift. =)
Member Since: Posts: Comments:
Quoting canuckmom:


That's interesting because I thought from everything that I've seen on the blog tonight that it was increasing. Why do you say waning?


I refer to NHC forecast. They're standing pat in regards to CONUS.
Member Since: Posts: Comments:
Quoting jpsb:

Ok, dumb question time. We have hundred of square miles of atmosphere spinning around at a fairly high velocity, but the eye of the strom is prefectly still and yet the eye is where the lowest pressure is and the eye is where all air is trying to get to. So my question is; Where is all that air going that is trying to get to the eye. It's got to be gong someplace it can't just stay whirling around the eye. thanks to anyone that answer my question.


DAM! I got everything....LOL! Here is your answer in a video on my site!
Member Since: Posts: Comments:
So while I'm at it, if I'm gonna get banned, I really like your NovaFloridian accent! ROFL
Member Since: Posts: Comments:
1899. jpsb
Quoting TampaSpin:


William dig a hole well above sea level....LOL
Ike eye passed right over me. I live on Galveston Bay in Texas.
Member Since: Posts: Comments:
LOL! Okay I know we aren't supposed to post this stuff, but the blog's getting quiet. That was cute! I usually just lurk and keep my mouth shut!
Member Since: Posts: Comments:
Quoting Sharkseatmore:
My wife is from Nova Scotia, I'm from Florida.... we end up say how ya'll doing eh?


LOL.
Member Since: Posts: Comments:
Have no answer but love the question. I've learned so much on this site.
Member Since: Posts: Comments:
Quoting Elena85Vet:


CONUS landfall threat continues to wane. Less spectators.


That's interesting because I thought from everything that I've seen on the blog tonight that it was increasing. Why do you say waning?
Member Since: Posts: Comments:
1893. jpsb
Quoting TampaSpin:


There is an ULL to its North that is causing it...YOu can see it on the Link i put up

Ok, dumb question time. We have hundred of square miles of atmosphere spinning around at a fairly high velocity, but the eye of the strom is prefectly still and yet the eye is where the lowest pressure is and the eye is where all air is trying to get to. So my question is; Where is all that air going that is trying to get to the eye. It's got to be gong someplace it can't just stay whirling around the eye. thanks to anyone that answer my question.
Member Since: Posts: Comments:
My wife is from Nova Scotia, I'm from Florida.... we end up say how ya'll doing eh?
Member Since: Posts: Comments:
Quoting gordydunnot:
The only negative so far is the trough in the central us seems to be flatting out. Although I do like the last jog north in the satellite photo.


I had said that earlier today....I noticed the high in the GOM had bulged NorthEast causing the trough to move more North.....Could be interesting to watch. I spoke of this in my Update i did yesterday.
Member Since: Posts: Comments:
Quoting SCwannabe:


I'm originally from Norhtern MN and we all say ehh too! Now I'm in South Carolina and I had to learn to say ya'all!


We flew out of Ely, Mn. matter of fact.
Member Since: Posts: Comments:
The only negative so far is the trough in the central us seems to be flatting out. Although I do like the last jog north in the satellite photo.
Member Since: Posts: Comments:
Quoting Elena85Vet:


LOL. I was gonna say "eh", but didn't know if it would be read right. LOL


It's one of "those" things that you don't even know you're doing. Kind of like the y'all from the south.
Member Since: Posts: Comments:
Night all...check back in tomorrow.
Member Since: July 2, 2009 Posts: 0 Comments: 2811
Tampa police over shot and killed Link
Member Since: Posts: Comments:
Quoting Elena85Vet:


LOL. I was gonna say "eh", but didn't know if it would be read right. I was in NW Ontario a few years back on an outpost fishing camp. The folks that ran the camp are from NS and spend their summers running it. They followed everything with "eh". Like "Bear tracks eh?", "Bear tracks Eh?" as they're following bear tracks into te woods. I'm saying "boat eh?", "boat eh?" LOL


I'm originally from Norhtern MN and we all say ehh too! Now I'm in South Carolina and I had to learn to say ya'all!
Member Since: Posts: Comments:
Quoting canuckmom:
I have to admit, I'm watching this one. We have family in lower Manhattan and I sure hope it doesn't make much more of a westerly jog!
You are very wise, Pay attention and be prepared. That does not mean you will be affected. But as weather 456 stated earlier, pay attention.
Member Since: Posts: Comments:
Quoting canuckmom:


Cause up here in Canada we say "eh!" Not "Aye" LOL It must be the accent


LOL. I was gonna say "eh", but didn't know if it would be read right. I was in NW Ontario a few years back on an outpost fishing camp. The folks that ran the camp are from NS and spend their summers running it. They followed everything with "eh". Like "Bear tracks eh?", "Bear tracks Eh?" as they're following bear tracks into te woods. I'm saying "boat eh?", "boat eh?" LOL
Member Since: Posts: Comments:
I have to admit, I'm watching this one. We have family in lower Manhattan and I sure hope it doesn't make much more of a westerly jog!
Member Since: Posts: Comments:
Quoting SCwannabe:
How far West would Bill have to make it to start making the NHC get nervous?


70W seems to be the consensus.
Member Since: Posts: Comments:
BEWARE, A MAJOR STORM WILL HIT FLORIDA THIS YEAR!
Member Since: Posts: Comments:
Quoting Elena85Vet:


Being from NS, I'm wondering why you don't finish your posts off with "aye"? j/k :)


Bill's got such a big "aye", it's pretty hard to compete.
Member Since: Posts: Comments:
Quoting Elena85Vet:


Being from NS, I'm wondering why you don't finish your posts off with "aye"? j/k :)


Cause up here in Canada we say "eh!" Not "Aye" LOL It must be the accent
Member Since: Posts: Comments:
Thank god the trough at 70 is still there ,it missed the first one only slightly influenced. I guess will know in the morning.
Member Since: Posts: Comments:
Appears all is as expected here, Huricane still spinning. Models all still in agreement. Wait watch and see and no one seems to be getting overly hyper as we watch and see! ( that last point is somewhat unusual) Hopefully everyone near or close to near of the expected track has a plan and is prepared,
Member Since: Posts: Comments:
How far West would Bill have to make it to start making the NHC get nervous?
Member Since: Posts: Comments:
Quoting TampaSpin:


William dig a hole well above sea level....LOL


I'm a-hunkering, fer sure, fer sure.
Member Since: Posts: Comments:

Viewing: 1924 - 1874

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46Blog Index

Top of Page

About

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