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

By: Dr. Jeff Masters , 03:28 PM GMT on Αύγουστος 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: 74 - 24

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

A Cat 4, West of Bermuda in a few days is too close for comfort for this East Hampton, Long Island weather watcher! A couple of questions for those more experienced:

1- Where will that Bermuda high be in 2 days, and will Bill slip under it, or blast it.

2- What is the bias for a major hurricane? Refresh my memory, does it tend to go left or right when it is so strong? With only warmer waters and low shear ahead over next few days, it only looks to get more intense, which is why I ask about the bias. Big storms can make their own weather.

Thanks!
Member Since: Posts: Comments:
Hurricane Bill may not be headed for mainland, but he is a frieght train of heat headed for the northern seas. Good luck Greenland Ice cap.
Member Since: Posts: Comments:
Quoting jurakantaino:
In Puerto Rico the humid outflow of Bill is bringing scatter showers to the area and breeze conditions. Waves are increasing rapidly.
U guys are going to get some serious wave action along the north coast all weekend, it seems.....

Glad it seems it won't be any worse.....
Member Since: Posts: Comments:
Quoting TropicTraveler:
Chicklit - I too was wondering about how the wave heights within the storm translate to wave heights that later hit the shores nearby. For example - yesterday 55 ft wave heights were shown on a buoy within the storm - yet the wave height projections on the shore were much lower amounts.

And Squawk - what's with the sarcasm? Seems like a very good observation from Chicklit and a good question that a lot of people on here are knowledgeable enough to answer.


Guess I missed it, but I did not see a question in there anywhere. Maybe my browser is dropping text, ya think?
Member Since: Posts: Comments:
Quoting willdunc79:


First! (2nd guesser) lets see how many more come along in the next hour.


it was a question, not a guesser. is that not what this blog is for? to ask questions that you are not sure about.
Member Since: Posts: Comments:
Rit from Cape Cod here. Just a little wobble to the West and we might get more than a mild blow. Surfer's and wind-surfers are going to go crazy happy with it. I'm still sitting on the fence waiting to see what happens.

Even my wunderground has only gotten our weather right about 40% of the time for the past year.

The rain they say we're going to get goes to our West and North, we've barely gotten any of the rain that's predicted, but we've gotten weather that wasn't s'posed to hit us plenty. So... I'm still watching Bill.
Member Since: Αύγουστος 15, 2004 Posts: 23 Comments: 380
Quoting jurakantaino:
In Puerto Rico the humid outflow of Bill is bringing scatter showers to the area and breeze conditions. Waves are increasing rapidly.

About 30 minutes ago we had showers with gusty winds that lasted about 5 minutes. Now we have a beautiful sunny day. It went by so quickly!
Member Since: Posts: Comments:
67. jpsb
Quoting Floodman:
Quoting reedzone:


Hurricane Isabel in 2003 busted through the trough and hit the Carolinas. It's slim, but there is a chance Bill could do that.


Bear in mind that Isabel was an annular storm; annuklar stiorms are less effected by shear and marginal conditions...I just can't recall whether or not the effects of trof and lows are the same or decreased for annulars
I am pretty sure Hurricane Allen did too. It is from Allen that I learned that a hurricane can build a temporary ridge against a weak low if it is pumping out move air than the low can move. Needless to say it's got to be a really big powerful hurricane and a weak low trof.
Member Since: Ιούνιος 30, 2009 Posts: 0 Comments: 1013
Quoting rwdobson:
Looking at the archive...I don't think Isabel really "busted" a trough. Here's what NHC discussion was saying @ 5am Sept 13 2003 "IT
APPEARS THAT THE TROUGH WHICH IS CURRENTLY ERODING THE WESTERN
PORTION OF THE RIDGE WILL WEAKEN AND THE HIGH WILL EXPAND WESTWARD."

This was about 5 days before landfall....


This sounds more like what I remember.....
Member Since: Posts: Comments:
Quoting mkmand:
Bill is one large and tall Hurricane lattitude wise. I've never seen a Hurricane like that before.

Any guesses on what would be Bill's peak intensity. I would say 140 mph, 24 hours from now, with pressure ~940 mb


150 with a pressure around 935 would be my guess.
However 160 Category 5 certainly is possible as the SSTs increase.
Member Since: Posts: Comments:
In Puerto Rico the humid outflow of Bill is bringing scatter showers to the area and breeze conditions. Waves are increasing rapidly.
Member Since: Posts: Comments:
Quoting BahaHurican:
3742. BahaHurican 11:37 AM EDT on August 19, 2009
Quoting GwadaGeek:

The date on the picture is... april 2008. Quite a sunny day here in Guadeloupe...
One of the things that always amuses me is how absolutely beautiful the weather can be when a storm is travelling. It's as if the storm sucks up all the clouds for hundreds of miles around it.





I think it creates high pressure on the 'outside' of the storm as air is sucked into the center and spills over the top. so to speak.
Member Since: Posts: Comments:
Chicklit - I too was wondering about how the wave heights within the storm translate to wave heights that later hit the shores nearby. For example - yesterday 55 ft wave heights were shown on a buoy within the storm - yet the wave height projections on the shore were much lower amounts.

And Squawk - what's with the sarcasm? Seems like a very good observation from Chicklit and a good question that a lot of people on here are knowledgeable enough to answer.
Member Since: Posts: Comments:
Quoting TriniGirl26:
Quoting pearlandaggie:
Do we have any friends on the blog that live in the Antilles?

Don't Know if i count. I'm from Trinidad...lol..party cloudy here...expecting rain in about 30 mins.


Of course you count! are the waves kicking up yet?
Member Since: Posts: Comments:
Quoting Walshy:
Bill has a nice outflow to the south-east but not on the west side.



WAlshy - Your picture mataches your avatar. All I see is a red X...
Member Since: Posts: Comments:
Looking at the archive...I don't think Isabel really "busted" a trough. Here's what NHC discussion was saying @ 5am Sept 13 2003 "IT
APPEARS THAT THE TROUGH WHICH IS CURRENTLY ERODING THE WESTERN
PORTION OF THE RIDGE WILL WEAKEN AND THE HIGH WILL EXPAND WESTWARD."

This was about 5 days before landfall....


Member Since: Ιούνιος 12, 2002 Posts: 0 Comments: 1574
Quoting reedzone:


Hurricane Isabel in 2003 busted through the trough and hit the Carolinas. It's slim, but there is a chance Bill could do that.


Bear in mind that Isabel was an annular storm; annular stiorms are less effected by shear and marginal conditions...I just can't recall whether or not the effects of trof and lows are the same or decreased for annulars
Member Since: Posts: Comments:
Quoting Chicklit:
Bill's big waves
. . .NOAA Wavewatch III model suggests that significant wave heights near Bill's center will reach 50 feet on Sunday. . . . a few huge waves near Bill's center may reach 95 feet high.
Holy cow Dr. Masters!
Great news for Bermuda:
High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.



and the purpose of your post was what?
Member Since: Posts: Comments:
Quoting leelee75k:
Thanks Dr. Masters. The confidence that the NHC and other meteorologists like Dr Masters have in this trough and Bill's path should be comforting to all of us. Seems forcasting is and has gotten better so therefore, we should all stop watching Bill and go on with our lives. We are all safe and that's a good thing.
leelee, some of us are just too paranoid to stop watching until it's gone ..... lol

But maybe we can not be so stressed....
Member Since: Posts: Comments:
The current Hurricane Hunter mission has just descended to 10,000 ft and commenced its run into the center of the storm. We should have another vortex message in about 30 minutes - it'll be interesting to see the central pressure.
Member Since: Posts: Comments:
Bill has a nice outflow to the south-east but not on the west side.

Member Since: Posts: Comments:
53. jpsb
Quoting rwdobson:
@41, yes, you are correct, a high is a dome of air. most upper level maps actually show height, not pressure.
Thank you, I am doing my know MET 101 and want to get a good handle on the basics.
Member Since: Ιούνιος 30, 2009 Posts: 0 Comments: 1013
hi reedzone,

that is kind of what I was wondering. was there ever a previous storm that the trough did not effect it? was isabel the only one?
Member Since: Posts: Comments:
Quoting pearlandaggie:
Do we have any friends on the blog that live in the Antilles?

Don't Know if i count. I'm from Trinidad...lol..party cloudy here...expecting rain in about 30 mins.
Member Since: Posts: Comments:
It's been overcast here for a while.....


Member Since: Posts: Comments:
Bill's big waves
. . .NOAA Wavewatch III model suggests that significant wave heights near Bill's center will reach 50 feet on Sunday. . . . a few huge waves near Bill's center may reach 95 feet high.
Holy cow Dr. Masters!
Great news for Bermuda:
High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.

Member Since: Posts: Comments:
Quoting WaterWitch11:
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.

Are you a 100% sure that the trough will turn this North? I just worry that so many many people are banking on the fact that this is true.


First! (2nd guesser) lets see how many more come along in the next hour.
Member Since: Posts: Comments:
Quoting IKE:
Dr. Masters new blog....check.
Wishcasters back in their shell...check.
Ana dead....check.


High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.....

Good news for Bermuda.....

Thanks doc!


Ike got it right again!! CHECK
Member Since: Posts: Comments:
Quoting reedzone:


Hurricane Isabel in 2003 busted through the trough and hit the Carolinas. It's slim, but there is a chance Bill could do that.
I think I'm going to go back and read the report on Isabel. I admit I don't remember any "trough-busting" type comments made about her.

Even if so, I'd like to know what kind of trough it was she busted through. Weak? Mediocre? Strong? All troughs are not created equal. On top of that, Isobel was the one in 100 genuine article annular storm; Bill is certainly not that.

I'm not expecting any "trough-busting" with that final trough this weekend. After all, even Wilma obeyed her trough.....

Member Since: Posts: Comments:
@41, yes, you are correct, a high is a dome of air. most upper level maps actually show height, not pressure.
Member Since: Ιούνιος 12, 2002 Posts: 0 Comments: 1574
Short lived storms in 2009. Bill should be the exception though as it heads north to Canada.

Member Since: Posts: Comments:
Bill is one large and tall Hurricane lattitude wise. I've never seen a Hurricane like that before.

Any guesses on what would be Bill's peak intensity. I would say 140 mph, 24 hours from now, with pressure ~940 mb
Member Since: Posts: Comments:
Hi all.

I noticed the Navy model has Bill making contact/grazing upper New England. How reliable is that model, and what should we yankees be looking for to get a better idea of Bill's track?
While I am a huge fan of dramatic weather events, I am also working on possible evacuation plans for my family should Kennebunkport, ME face imminent danger.

Thanks guys.
Member Since: Posts: Comments:
41. jpsb
Quoting reedzone:


Hurricane Isabel in 2003 busted through the trough and hit the Carolinas. It's slim, but there is a chance Bill could do that.
Now that we got that one cleared up, I still like to know if highs are taller then lows. By that I mean are the tops of high at a higher altitude then the tops of lows? Or our the tops of both at the same altitude but of different densities. (That is sitting next to one another at the same latitude of course.) thanks
Member Since: Ιούνιος 30, 2009 Posts: 0 Comments: 1013
I live in PR.
Member Since: Posts: Comments:
Quoting Walshy:
Pin hole eye on Typhoon Vamco

This looks like it's building.
Member Since: Posts: Comments:
38. IKE
Quoting BahaHurican:
Hey. Some of the Antilles-based bloggers were on last night. (Don't forget 456 lives in St. Kitts.) Dunno if anybody's about this a.m., though.


456 was on early this morning. Said he would be back this afternoon.
Member Since: Ιούνιος 9, 2005 Posts: 23 Comments: 37858
The thing is, Isabel was never expected to take a sharp turn in the same way Bill is now. Go back and look at the archive. And the trough did pick it up and move it north, it just happened when the storm was far enough east that it hit the US.
Member Since: Ιούνιος 12, 2002 Posts: 0 Comments: 1574
Quoting pearlandaggie:
Do we have any friends on the blog that live in the Antilles?
Hey. Some of the Antilles-based bloggers were on last night. (Don't forget 456 lives in St. Kitts.) Dunno if anybody's about this a.m., though.
Member Since: Posts: Comments:
Hurricanes and Troughs, Interesting , but not a short read :)

http://ams.allenpress.com/perlserv/?request=get-document&issn=1520-0493&volume=130&issue=09&page=22 10&ct=1

Idealized Numerical Simulations of Hurricane%u2013Trough Interaction
Member Since: Ιούνιος 12, 2005 Posts: 6 Comments: 8183
Not weather related but I just got this: -- Television pioneer Don Hewitt, the creator of "60 Minutes," has died, CBSNews.com reports. RIP
Member Since: Posts: Comments:
Quoting reedzone:


Hurricane Isabel in 2003 busted through the trough and hit the Carolinas. It's slim, but there is a chance Bill could do that.

Yep. StormW also mentioned that as well.
Member Since: Ιούνιος 29, 2009 Posts: 13 Comments: 5238
Good Evening/Morning all.
I see we could have 2 Cat 4's on earth at once.
Hurricane Bill and Typhoon Vamco.
Also, My blog auto updates. I will be adding to it over time, so if you want to know the latest weather in OZ, Have a look, leave a comment.
Cheers AussieStorm
Member Since: Posts: Comments:
Quoting WaterWitch11:
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.

Are you a 100% sure that the trough will turn this North? I just worry that so many many people are banking on the fact that this is true.

I am no expert but I wouldnt say that its a 100% sure. These models are not that accurate after 3-5 days. I remember that when Bill was in the middle of the Atlantic the track was aimed at PR and looked what happened.

I am NOT saying that it will hit the US. I am only saying that the models are not 100% accurate in the long run. So far the NHC has done a great job with Bill (short term). Just keep an eye on the system and be prepared...we should all be in hurricane season.
Member Since: Posts: Comments:
Quoting lizrod43:
let the 2nd guessing begin...



lol
Member Since: Posts: Comments:
Quoting reedzone:


Hurricane Isabel in 2003 busted through the trough and hit the Carolinas. It's slim, but there is a chance Bill could do that.


Wasn't it forcasted to do that though?
Member Since: Posts: Comments:
28. IKE
Dr. Masters new blog....check.
Wishcasters back in their shell...check.
Ana dead....check.


High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.....

Good news for Bermuda.....

Thanks doc!
Member Since: Ιούνιος 9, 2005 Posts: 23 Comments: 37858
Thanks Dr. Masters. The confidence that the NHC and other meteorologists like Dr Masters have in this trough and Bill's path should be comforting to all of us. Seems forcasting is and has gotten better so therefore, we should all stop watching Bill and go on with our lives. We are all safe and that's a good thing.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Good morning! Thanks Dr. Masters. It definitely has been a cooler July and August here! It's the middle of August and I haven't had to us my A/C since last Friday!
Member Since: Posts: Comments:

Viewing: 74 - 24

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.

Local Weather

Partly Cloudy
45 ° F
Λίγο Νεφελώδης