Bill intensifies to Category 4; globe has 5th warmest July on record
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
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4:40 PM GMT en Agosto 19, 2009
A hurricane can break through a short wave trough or upper-level cold low, although the passage will weaken it. A hurricane cannot break through a major long wave trough like the one approaching Bill this weekend. In some cases, a long wave trough will move too quickly or not extend far enough south to fully recurve a hurricane, leaving the hurricane behind after the trough passes. That will not be the case with this weekend's trough, which is unusually strong will reach unusually far south for this time of year.
Jeff Masters
Good loop of entire Atlantic Africa too!
Can you be a little more specific on this?? How bad is that or would that be?
Yea well, some people.
06Z GFS
12Z GFS
Uhh, yes it does matter if the NHC predicted it. It means that it's not some random, unpredictable thing that could happen to Bill without warning, like some of the doom/wishcasters seem to want. It's a phenomenon that the models are able to predict...
You're missing my point: the 850 mb vorticity IS the LLC for the storm; no vorticity at 850, no low level circulation. The 850mb vorticity can't strengthen the storm, it IS the storm. If something else strengthenms the storm the vorticity at that level (and lower even) can strengthen, but the vorticity is a function of the strengthening, not the element that strengthens it
I don't like the look of that HWRF, it has bill staying over warm water longer and puts St. John's into the eastern Eyewall.
I realize that it may be wrong, but what does it say for September?
That is part of the trough, but the "kicker" part is just developing. Single step through HPC's 7 Day Surface Analysis. The main part comes out of North Dakota, which you can see starting looking at Western U.S. - Water Vapor Loop
Good way to put it, Storm! Pretty much my sentiments, especially if the GFS forecast pans out past 7 days.
...unless it were to be strong enough to advect vorticity from some other, nearby feature. Happens. (But I do not see that being the case with Ana-wave)
Maritimes BE PREPARED!
I confused. Crap as in oh darn or crap as in not true.
Certainly, but with the wave formerly known as Ana you are correct...
If that's what you meant, it is not clear in your forecast. You talk about how small the ULL is, and you never use the terms long-wave or short-wave...
One more question and I appreciate you being patient with me. Our local NWS is saying the front is supposed to stall? is this the same trough we are speaking of? So It sounds like a matter of timing then?
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND ACROSS THE AREA FROM THE
ATLANTIC THROUGH FRIDAY. A COLD FRONT WILL APPROACH FROM THE WEST
SATURDAY AND STALL OVER THE EASTERN CAROLINAS BEFORE WASHING OUT
THROUGH EARLY NEXT WEEK. HURRICANE BILL IS EXPECTED TO EVENTUALLY
CURVE NORTH AND REMAIN WELL EAST OF THE REGION. INCREASING OCEAN
SWELLS FROM HURRICANE BILL WILL INCREASE THE THREAT OF RIP
CURRENTS AND HIGH SURF FROM FRIDAY THROUGH THE WEEKEND.
Thanks for clearing that up. Isabel blew through here with winds of 60, and im well inland.
That was cool! So was that an official Trough Bust? Looked like that was a much weaker trough than the one Bill has to contend with.
That's a large eye, open on the southwest, with minimum central pressure continuing to decline, albeit slowly. The actual observed winds continue to be lower than the T numbers would predict, but the gap has somewhat narrowed. And the windfield, to judge by the HCH current path to the southeast, remains formidably large.
My lurking goes better with you 2 helping the flow of info.
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
Transmitted: 19th day of the month at 16:40Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number: 03
Storm Name: Bill (flight originating in the North Atlantic basin)
Mission Number: 2
Observation Number: 07
Part A...
Date: Near the closest hour of 16Z on the 19th day of the month
Highest Mandatory Level For Which Wind Was Reported: 700mb
Coordinates: 19.3N 56.7W
Location: 616 miles (991 km) to the E (84) from San Juan, Puerto Rico (USA).
Marsden Square: 042 (About)
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
968mb (28.59 inHg) Sea Level (Surface) 25.2C (77.4F) 25.2C (77.4F) 5 (from the N) 85 knots (98 mph)
1000mb -289m (-948 ft) Other data not available.
925mb 398m (1,306 ft) 22.4C (72.3F) 22.4C (72.3F) 20 (from the NNE) 125 knots (144 mph)
850mb 1,134m (3,720 ft) 19.6C (67.3F) 19.6C (67.3F) 45 (from the NE) 100 knots (115 mph)
700mb 2,794m (9,167 ft) Unavailable Unavailable 65 (from the ENE) 98 knots (113 mph)
Information About Radiosonde:
- Launch Time: 16:08Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.
Remarks Section...
Dropsonde Location: Dropped in eyewall. (315 - This is either the radians or degrees to the eye center. Our system cannot tell the difference.)
Splash Location: 19.19N 56.79W
Splash Time: 16:12Z
Release Location: 19.27N 56.71W
Release Time: 16:08:24Z
Splash Location: 19.19N 56.79W
Splash Time: 16:11:59Z
Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 15 (from the NNE)
- Wind Speed: 114 knots (131 mph)
Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 40 (from the NE)
- Wind Speed: 107 knots (123 mph)
- Depth of Sounding: From 697mb to 967mb
Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 159 gpm - 9 gpm (522 geo. feet - 30 geo. feet)
- Wind Direction: 5 (from the N)
- Wind Speed: 98 knots (113 mph)
Sounding Software Version: AEV 20801
Part B: Data For Significant Levels...
Significant Temperature And Relative Humidity Levels...
Level Air Temperature Dew Point
968mb (Surface) 25.2C (77.4F) 25.2C (77.4F)
850mb 19.6C (67.3F) 19.6C (67.3F)
762mb 15.0C (59.0F) 15.0C (59.0F)
718mb 14.2C (57.6F) 13.4C (56.1F)
702mb Unavailable
697mb 10.4C (50.7F) 10.4C (50.7F)
Significant Wind Levels...
Level Wind Direction Wind Speed
968mb (Surface) 5 (from the N) 85 knots (98 mph)
959mb 5 (from the N) 95 knots (109 mph)
953mb 10 (from the N) 110 knots (127 mph)
950mb 10 (from the N) 115 knots (132 mph)
944mb 10 (from the N) 114 knots (131 mph)
936mb 10 (from the N) 124 knots (143 mph)
931mb 15 (from the NNE) 122 knots (140 mph)
921mb 20 (from the NNE) 127 knots (146 mph)
901mb 25 (from the NNE) 113 knots (130 mph)
893mb 30 (from the NNE) 120 knots (138 mph)
879mb 35 (from the NE) 117 knots (135 mph)
872mb 40 (from the NE) 120 knots (138 mph)
865mb 45 (from the NE) 115 knots (132 mph)
857mb 45 (from the NE) 103 knots (119 mph)
850mb 45 (from the NE) 100 knots (115 mph)
793mb 55 (from the NE) 121 knots (139 mph)
697mb 65 (from the ENE) 96 knots (110 mph)
The highest wind observed in the "Significant Wind Levels" section is noted in bold.
191507Z AUG 09
FM NMFC
BT
UNCLAS
MSGID/NMFC/OVLY2/0087/AUG
OVLY/ATL STORM 03L/191200Z3/AUG/1OF1/HURRICANE BILL(03L)/METOC
TEXT/12//G/181800N8/0553600W9/H
TEXT/12//G/214200N9/0610000W7/H
TEXT/12//G/260000N8/0653000W4/H
TEXT/12//G/320000N5/0683000W7/H
TEXT/12//G/383000N4/0670000W3/H
TEXT/12//G/470000N1/0580000W3/H
LINE/6//G/181800N8/0553600W9/214200N9/0610000W7/260000N8/0653000W4
/320000N5/0683000W7/383000N4/0670000W3/470000N1/0580000W3
ARC/0/G///181800N8/0553600W9/150NM/150NM
ARC/0/G///214200N9/0610000W7/180NM/180NM
ARC/0/G///260000N8/0653000W4/180NM/180NM
ARC/0/G///320000N5/0683000W7/180NM/180NM
TEXT/12//G/161800N6/0530600W4/HURRICANE BILL
TEXT/12//G/151800N5/0530600W4/19 AUG 1200Z
TEXT/12//G/141800N4/0530600W4/MAX 115 KT
TEXT/12//G/131800N3/0530600W4/300 AT 16 KT
TEXT/12//G/121800N2/0530600W4/34 KT RADII SHOWN
TEXT/12//G/214200N9/0570000W2/2012Z MAX 125
TEXT/12//G/260000N8/0613000W0/2112Z MAX 120
TEXT/12//G/320000N5/0643000W3/2212Z MAX 115
TEXT/12//G/383000N4/0630000W9/2312Z MAX 100
TEXT/12//G/470000N1/0540000W9/2412Z MAX 75
ENDAT
BT
#0001
NNNN
WTNT02 KNGU 191502
SUBJ: HURRICANE BILL (03L) WARNING NR 017
1. HURRICANE BILL (03L) WARNING NR 017
01 ACTIVE TROPICAL CYCLONE IN ATLANTIC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
191200Z --- NEAR 18.3N 55.6W
MOVEMENT PAST SIX HOURS - 300 DEGREES AT 16 KTS
POSITION ACCURATE TO WITHIN 015 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT
RADIUS OF 064 KT WINDS - 070 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
150 NM NORTHWEST QUADRANT
REPEAT POSIT: 18.3N 55.6W
---
FORECASTS:
12 HRS, VALID AT:
200000Z --- 19.9N 58.3W
MAX SUSTAINED WINDS - 120 KT, GUSTS 145 KT
RADIUS OF 064 KT WINDS - 070 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
160 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
160 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 305 DEG/ 15 KTS
---
24 HRS, VALID AT:
201200Z --- 21.7N 61.0W
MAX SUSTAINED WINDS - 125 KT, GUSTS 155 KT
RADIUS OF 064 KT WINDS - 070 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
175 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
180 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 310 DEG/ 15 KTS
---
36 HRS, VALID AT:
210000Z --- 23.5N 63.5W
MAX SUSTAINED WINDS - 125 KT, GUSTS 155 KT
RADIUS OF 064 KT WINDS - 070 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
175 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
180 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 325 DEG/ 15 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
211200Z --- 26.0N 65.5W
MAX SUSTAINED WINDS - 120 KT, GUSTS 145 KT
RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
175 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
180 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 335 DEG/ 16 KTS
---
72 HRS, VALID AT:
221200Z --- 32.0N 68.5W
MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT
RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
170 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
170 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 010 DEG/ 17 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 225 NM
ON DAY 4 AND 300 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
231200Z --- 38.5N 67.0W
MAX SUSTAINED WINDS - 100 KT, GUSTS 120 KT
VECTOR TO 120 HR POSIT: 035 DEG/ 27 KTS
---
120 HRS, VALID AT:
241200Z --- 47.0N 58.0W
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
---
REMARKS:
191500Z POSITION NEAR 18.7N 56.3W
OR APPROX 380 NM ENE OF THE LEEWARD ISLANDS.
12 FT SEAS: 360NM NE, 300NM SE, 210NM SW, 310NM NW.
NEXT WARNINGS AT 192102Z, 200302Z, 200902Z AND 201502Z.//
BT
#0001
NNNN
Yes, and the global warming skeptics are bruiting the latter from the rooftops . . . even though the arctic ice meltdown looks like it's heading for a record year.
When will they ever learn . . . when will they ever learn?
Hello DR. Masters,
Have you noticed the GOM High bulging to the NE making the trough ride over the top more than expected. I may be wrong but, is this why the models have moved more West some. I May be wrong.....here is a nice WV look
Howdy, Fire...how's things?
So based on this new development... it could explain why current and may future runs of forecast models are hinting towards cyclogenesis in the ATL still.
To me, different explanations of the same thing, understood both.
Well, this is a little dated, but accurate: http://www.usclivar.org/Organization/MJO%20WorkingGroup/MJO-Hurricanes.html
The forecasted short-term and long-term MJO results I posted are heavily in the western phase direction.
Comments would be appreciated.
Oh. Well CRAP! LOL
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