Bonnie weakens to a tropical depression
Tropical Depression Bonnie is nearing the end of its traverse of South Florida, and passage over land has significantly disrupted the small storm. Satellite images show almost no heavy thunderstorms near Bonnie's center of circulation, and the center is now exposed to view. Radar-estimated rainfall from the Key West radar shows that Bonnie dumped very little rain on South Florida--maximum rainfall amounts from the storm were about four inches over a small region southwest of Miami. Water vapor satellite loops show that Bonnie is embedded in a large area of dry air, thanks to an upper level low to the west over the Gulf of Mexico. This low has brought an increasing amount of wind shear to Bonnie today, and shear has increased from 20 knots this morning to 25 knots this afternoon. Surface observations in South Florida currently don't show any tropical storm force winds. Bonnie's top winds today were at Fowey Rocks, which had sustained winds of 46 mph, gusting to 53 mph, at 10:45 am EDT.
Figure 1. Satellite image of Bonnie from NASA's MODIS instrument, taken at 17:10 UTC July 23, 2010. Image credit: NASA/.
Track Forecast for Bonnie
The latest set of model runs from 8am EDT (12Z) are very similar to the three previous sets of runs, and this degree of consistency gives me confidence that Bonnie will stay within the cone of uncertainty depicted on the track forecast images. The projected track will take Bonnie over the oil spill region, and the storm's strong east to southeasterly winds will begin to affect the oil slick on Saturday morning. Assuming Bonnie doesn't dissipate over the next day, the storm's winds, coupled with a likely storm surge of 2 - 4 feet, will drive oil into a substantial area of the Louisiana marshlands. However, the current NHC forecast has Bonnie making landfall in Louisiana near 9pm CDT Saturday night. According to the latest tide information, this will be near the time of low tide. This will result in much less oil entering the Louisiana marshlands than occurred during Hurricane Alex in June. That storm brought a storm surge of 2 - 4 feet and sustained winds of 20 - 30 mph that lasted for several days, including several high tide cycles. The latest oil trajectory forecasts from NOAA (Figure 2) predicts potential oil impacts along a 150-mile stretch of Louisiana coast on Sunday.
Figure 2. Oil Trajectory forecast for Sunday for the Deepwater Horizon oil spill. Image credit: NOAA.
Intensity Forecast for Bonnie
Bonnie has been disrupted by its passage over land, and it will take at least six hours for the storm to reorganize once it moves over the warm waters of the Gulf of Mexico tonight. This process will be hindered by the large upper-level low to its west. If the low remains in its present location, relative to Bonnie, it will bring high wind shear of about 20 - 30 knots to the storm. This will allow for only slow intensification, or may even destroy Bonnie. Bonnie is unlikely to intensify to more than a 50 mph tropical storm, and I give a 30% chance it will dissipate over the Gulf of Mexico before making landfall. The GFDL model predicts Bonnie could hit the Gulf Coast as a 50 mph tropical storm, but the other major models such as the HWRF, GFS, ECMWF, and NOGAPS show a much weaker storm. I don't give Bonnie any chance of becoming a hurricane. NHC is putting the odds of Bonnie being a hurricane at 2 pm Saturday at 4% (5pm advisory.)
If you are wondering about the specific probabilities of receiving tropical storm force winds at your location, I recommend the wind probability product from NHC. The latest probabilities of various locations getting tropical storm force winds, 39 mph or higher, from the 5pm EDT advisory:
Buras, LA 30%
New Orleans 28%
Mobile, AL 37%
Pensacola, FL 30%
Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami
Next update
I'll have an update Saturday morning.
Jeff Masters
Reader Comments
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 — Blog Index
18z Early Cycle NHC model tracks
Bonnie
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)
Dynamic Models (More sophisticated models)
Early Model Wind Forecasts
Pat...you have WU mail...
v/r
Jon
I wonder if that ULL will be loosing steam? There is some moisture being brought into that low and the wator vapor imagery is showing the low to flatten out at the bottom.
Eggcellent.
Almost as good as the Popeyes chicken too
This guy from the houston chronicle does a good job on tracking hurricanes without the hype.
I feel I face, My Final Advisory"..
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032010
500 PM EDT FRI JUL 23 2010
SATELLITE IMAGERY AND RADAR OBSERVATIONS INDICATE THAT BONNIE HAS
BECOME LESS ORGANIZED WHILE MOVING INLAND OVER SOUTHERN FLORIDA.
THE CENTER IS TO THE SOUTHEAST OF AN AREA OF SHAPELESS DEEP
CONVECTION. GIVEN THE CURRENT ORGANIZATION AND SURFACE
OBSERVATIONS...THE INITIAL INTENSITY HAS BEEN LOWERED TO 30 KNOTS.
THE ENVIRONMENT IN THE GULF OF MEXICO IS FORECAST TO REMAIN
UNFAVORABLE FOR STRENGTHENING MAINLY DUE TO STRONG WIND SHEAR. WITH
THE EXCEPTION OF THE STATISTICAL MODELS WHICH BRING THE WINDS UP A
LITTLE BIT...NONE OF THE DYNAMICAL GUIDANCE RESTRENGTHENS BONNIE IN
THE GULF OF MEXICO. BASED ON CONTINUITY AND THE STATISTICAL
MODELS...THE OFFICIAL FORECAST CALLS FOR SLIGHT STRENGTHENING
BEFORE THE CYCLONE APPROACHES THE NORTH GULF COAST LATE SATURDAY.
HOWEVER...DEGENERATION INTO AN OPEN TROUGH IS ALSO POSSIBLE.
THE CENTER OF BONNIE HAS BEEN RAPIDLY CROSSING THE SOUTHERN FLORIDA
PENINSULA ABOUT 300 DEGREES OR WEST-NORTHWEST AT 16 KNOTS DURING
THE PAST FEW HOURS. BONNIE IS EMBEDDED WITHIN WELL-DEFINED
STEERING CURRENTS ASSOCIATED WITH THE FLOW BETWEEN A HIGH PRESSURE
SYSTEM OVER THE UNITED STATES AND AN UPPER-LOW OVER THE WESTERN
GULF OF MEXICO. THIS PATTERN IS FORECAST TO PERSIST...KEEPING
BONNIE ON THE SAME GENERAL TRACK THROUGH THE NEXT 2 TO 3 DAYS.IF
BONNIE SURVIVES AS A TROPICAL CYCLONE...ONLY A SMALL DECREASE IN
THE CURRENT FORWARD SPEED IS ANTICIPATED. SINCE THE STEERING
CURRENTS ARE WELL DEFINED AND THE GUIDANCE IS TIGHTLY CLUSTERED
THERE IS A GOOD CONFIDENCE IN THE TRACK FORECAST.
FORECAST POSITIONS AND MAX WINDS
INITIAL 23/2100Z 26.2N 81.9W 30 KT
12HR VT 24/0600Z 27.5N 84.5W 30 KT
24HR VT 24/1800Z 29.0N 87.5W 40 KT
36HR VT 25/0600Z 30.5N 90.0W 35 KT...INLAND
48HR VT 25/1800Z 31.5N 91.0W 25 KT...INLAND
72HR VT 26/1800Z 33.5N 93.0W 20 KT...POST-TROP/REMNT LOW
96HR VT 27/1800Z...DISSIPATED
$$
FORECASTER AVILA/ROBERTS
HOWEVER...DEGENERATION INTO AN OPEN TROUGH IS ALSO POSSIBLE.
A degenerate,..?
O man..
Im glad I dont use sarcasm..
Thats what Im sayin!!
There's a Hole in the GOM where a Hurricane should be..?
Saved by da ULL from Up above.
..literally.
I'll drink to dat.
I am not a "down caster" but I just do not think it will stay on that forcast track...
but I've been wrong before ... but I think Bonnie looks pretty bad...but maybe she will perk up a bit in the GOM...
We have a consolation prize..!
Time until Friday, December 21, 2012 at 11:11:11 AM (UTC time)
881 days
21158 hours
1269493 minutes
76169615 seconds
Alternative version
It is 881 days, 14 hours, 13 minutes and 35 seconds until Friday, December 21, 2012 at 11:11:11 AM (UTC time)
Current time is
Friday, July 23, 2010 at 20:57:36 UTC
Thanks in Advance.
No deep convection anywhere near the center...just a couple of light rainbands. It's not really a tropical cyclone anymore and with this environment staring it in the face I would doubt that any reorganization over the GOM is possible...it only has a day or so to do this, and when the storm is this decoupled and ill-defined it is just not likely.
(Unless, maybe, that was sarcasm?)
We should be more sensitive to tropical waves moving west through Caribbean. I think it's supose to eventually move into bay of Campeche before turning N into S Texas. Local NWS mets watching it for rain.
Look at the vis sat loop. there is an obvious but naked LLC at 26N 81.7W or right about over FT Myers..
Pouch discussion.
Thanx for that one Drak
I agree with you. I just looked at buoys within 60 miles of the listed coordinates. Nothing much there.
Spurious Bonnie may be true.
Isnt that how she started out? Maybe we've come full circle with her. :)
WNW
Viewing: 1 - 51
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 — Blog Index