Tropical Storm Bonnie Makes Her Debut

By: Dr. Jeff Masters , 4:32 AM GMT on July 23, 2010

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Hi everybody, this is Dr. Rob Carver filling in for Jeff on the late shift.

Based on information from Hurricane Hunters, the National Hurricane Center upgraded TD Three to Tropical Storm Bonnie. As of the 11PM EDT advisory, Bonnie was at 23.4N, 76.5W which is 285 miles southeast of Miami, Florida. Bonnie has maximum winds of 40 mph, a minimum central pressure of 1007 mb, and is moving to the northwest at 14 mph. Bonnie will pass over the Everglades/Florida Keys Friday and cross into the Gulf of Mexico Friday night/early Saturday morning. Tropical storm warnings are in effect for both Florida coasts south of Lake Okeechobee to Key West.


Fig. 1 IR satellite image of Tropical Storm Bonnie at 1216AM EDT.

Threats
NHC is expecting 2-4 inches of rain over south Florida due to Bonnie and 3-5 inches over the Bahamas. They are forecasting a storm surge of 1-2 feet. Tropical storm force winds are expected in the Bahamas starting Thursday night, and they are forecast to arrive in southern Florida Friday morning.

Impacts and Emergency Preparedness
As of 1130PDT EDT, the Key West NWS office is indicating that there are no evacuation orders in effect or planned for Monroe County (the Keys). Small craft are being advised to stay in port and be well secured to their docks. Two shelters will be opened, Key West High School and Stanley Switlik Elementary School in Marathon.

Most of the ships at the Deepwater Horizon oil spill site and other skimming ships have been ordered to seek safe harbor. In the statement, Adm. Allen said ships that operate the ROVs will be the last out and the first back to keep the wellhead observations going as long as possible.

Forecast/Model Assessment
The track models and ensemble models show remarkably good agreement for Bonnie's path across south Florida and towards southeast Louisiana. The current intensity forecast calls for Bonnie to maintain strong tropical storm force winds (40-50 knots) until it makes landfall in Louisiana, with a 15% chance of becoming a hurricane before then. However, the global models (GFS, Canadian GEM, NOGAPS) and the hurricane dynamical models (GFDL, Navy GFDL, and HWRF) do not intensify Bonnie at all. The statistical models (SHIPS and LGEM) support the intensity forecast.

I'm inclined to take the predictions of global and dynamical models with a large grain of salt. When I reviewed the latest model runs (18Z and 12Z), it was apparent that none of the models had a good initialization of Bonnie's structure. Bonnie has a relatively small circulation, so it's easy for the models' initialization to act like there isn't much of a storm there. Without accurate starting conditions, any model will have trouble producing an accurate forecast. NHC has a good summary of the different forecast models they use.

Next Update
Jeff will have an update sometime Friday morning.

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547. xcool
lol
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Quoting Ivanhater:
That 1010 was not the center noted by the strong winds at the surface


No that was not a vortex message, just a dropsonde inbound from NE.
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Quoting robert88:
What a stretched out weak mess. The ULL did a # on Bonnie. It will be downgraded soon. Conditions won't get any better in the GOM. Your looking at Bonnie at her peak.


Well looking at the Eastern US rgb. Showing fronts. And she just cant shake that ULL. And that is one big ridge. A front came south and that ridge said I don't think so little man. Lol.
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543. xcool


good

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Oh well she tried. Time for bed. Tired of looking at this mess lol Let's hope the next storm we track looks better than Bonnie.
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Quoting xcool:


eye ?
storms to east of center are already bending southwestward from the northeast flow
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That 1010 was not the center noted by the strong winds at the surface
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538. xcool
yeah she doom lol
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1010mb now. She is dying fast.
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536. xcool
Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 23rd day of the month at 07:28Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 305)
Storm Number: 03
Storm Name: Bonnie (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 09

Part A...

Date: Near the closest hour of 7Z on the 23rd day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 24.7N 77.4W
Location: 26 miles (41 km) to the S (189°) from Nassau, Bahamas.
Marsden Square: 080 (About)

Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1010mb (29.83 inHg) Sea Level (Surface) 28.0°C (82.4°F) 26.3°C (79.3°F) 110° (from the ESE) 36 knots (41 mph)
1000mb 91m (299 ft) 27.0°C (80.6°F) 25.4°C (77.7°F) 115° (from the ESE) 40 knots (46 mph)
925mb 778m (2,552 ft) 22.2°C (72.0°F) 22.0°C (71.6°F) 135° (from the SE) 42 knots (48 mph)
850mb 1,512m (4,961 ft) 18.6°C (65.5°F) 18.6°C (65.5°F) 135° (from the SE) 40 knots (46 mph)

Information About Radiosonde:
- Launch Time: 7:18Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...

Dropsonde Location: Dropped in maximum wind band.

Splash Location: 24.71N 77.46W
Splash Time: 7:20Z

Release Location: 24.69N 77.43W
Release Time: 7:18:07Z

Splash Location: 24.71N 77.45W
Splash Time: 7:20:19Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 120° (from the ESE)
- Wind Speed: 41 knots (47 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 130° (from the SE)
- Wind Speed: 41 knots (47 mph)
- Depth of Sounding: From 844mb to 1010mb

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: 115° (from the ESE)
- Wind Speed: 39 knots (45 mph)

Sounding Software Version: AEV 20801

Part B: Data For Significant Levels...

Significant Temperature And Relative Humidity Levels...
Level Air Temperature Dew Point
1010mb (Surface) 28.0°C (82.4°F) 26.3°C (79.3°F)
966mb 24.2°C (75.6°F) 24.0°C (75.2°F)
860mb 19.2°C (66.6°F) 18.6°C (65.5°F)
850mb 18.6°C (65.5°F) 18.6°C (65.5°F)
844mb 17.4°C (63.3°F) 17.4°C (63.3°F)

Significant Wind Levels...
Level Wind Direction Wind Speed
1010mb (Surface) 110° (from the ESE) 36 knots (41 mph)
1003mb 110° (from the ESE) 40 knots (46 mph)
994mb 115° (from the ESE) 38 knots (44 mph)
969mb 120° (from the ESE) 45 knots (52 mph)
855mb 135° (from the SE) 41 knots (47 mph)
844mb 135° (from the SE) 39 knots (45 mph)
The highest wind observed in the "Significant Wind Levels" section is noted in bold.


Member Since: Posts: Comments:
Quoting weatherwart:
When the coffee stops working, it's time for bed. I'll probably catch the 0800 update.

Night everyone!


Night weatherwart!
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When the coffee stops working, it's time for bed. I'll probably catch the 0800 update.

Night everyone!
Member Since: August 18, 2008 Posts: 0 Comments: 884
533. xcool
poof bye she go lollmao
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What a stretched out weak mess. The ULL did a # on Bonnie. It will be downgraded soon. Conditions won't get any better in the GOM. Your looking at Bonnie at her peak.
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530. 7544
everyone here is getting slap happy i dont know who to listen too ill just wait till dmax ends
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Quoting Eagle101:
FYI...Andros Town reported a station pressure of 28.88 inHg...977.98 milibars...surface winds from the east @ 17 mph...0600UTC...about one and a half hours ago...

v/r

Jon


The sensor is malfunctioning...Nassau airport also reported a similar reading at the same hour.
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Quoting Eagle101:
FYI...Andros Town reported a station pressure of 28.88 inHg...977.98 milibars...surface winds from the east @ 17 mph...0600UTC...about one and a half hours ago...

v/r

Jon


That must be a bad reading. Dropsonde dropped about 20 miles east of there just recorded 1010 at the surface.
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just had a thought... wouldn't it be funny if the next named storm would be "clyde" since it's a male name?
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525. 7544
lol
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Quoting TampaSpin:
My bad....my eyes are hurting with the colors on Google Earth......LOL...the orange was brown...LOL....it was 35-40mph winds.....LOL....its bed time it believe.......NITE everyone.


LOL good night...get some rest!
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FYI...Andros Town reported a station pressure of 28.88 inHg...977.98 milibars...surface winds from the east @ 17 mph...0600UTC...about one and a half hours ago...

v/r

Jon
Member Since: January 7, 2007 Posts: 0 Comments: 40
522. xcool


eye ?
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My bad....my eyes are hurting with the colors on Google Earth......LOL...the orange was brown...LOL....it was 35-40mph winds.....LOL....its bed time it believe.......NITE everyone.
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Quoting 7544:
bonnie if she dosent turn west shes going to slam into broward county


The COC is south of the large area of convection which will impact Broward County. Whether of not the HH finds a closed circulation this morning remains to be seen. I don't think they will.
Member Since: August 18, 2008 Posts: 0 Comments: 884
RECON just passed right through the ball of deep convection...still no flight level winds above what we've already seen. Now they will check to see if we still have a tropical cyclone.
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518. xcool
did i see eye no lies
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516. 7544
bonnie if she dosent turn west shes going to slam into broward county
Member Since: May 6, 2007 Posts: 0 Comments: 6874
514. xcool
7544 ?
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513. 7544
nice new fedder band forming
Member Since: May 6, 2007 Posts: 0 Comments: 6874
512. xcool
TampaSpin .poof lolol
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I beleive the COC is under the deep stuff that recon is now gettng ready to head into....could be wrong tho..
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509. 7544
oh wait i mean the open wave like you are saying lol
Member Since: May 6, 2007 Posts: 0 Comments: 6874
508. 7544
bonnir is now in the open waters right bet fla and andros is
Member Since: May 6, 2007 Posts: 0 Comments: 6874
496 Eagle101 " [radar loop] "

Wow, Bonnie's southside is as bare as MotherHubbard's cupboard.
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506. 7544
wahy
Member Since: May 6, 2007 Posts: 0 Comments: 6874
RECON making another center pass from NE to SW...let's see if they can find an actual closed circulation.
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504. IKE
Quoting IKE:
00Z ECMWF



Eastern ATL view through Aug. 2nd.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting CoopNTexas:
EURO shows ZIPPO...NADA

NIGHT!!!


It shows yet another system for TX/MX. Unfortunately. At least rain.
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502. xcool
40 knot winds at flight
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http://www.tropicalatlantic.com/recon/ge/Recon_Data_for_the_Atlantic_Basin.kmz

This is reoon on google earth..
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498. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #43
TROPICAL DEPRESSION, FORMER CHANTHU (T1003)
15:00 PM JST July 23 2010
============================

At 6:00 AM UTC, Tropical Depression, Former Chanthu (1000 hPa) located at 23.0N 107.0E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west northwest at 10 knots.

THIS IS THE FINAL TROPICAL DISTURBANCE ADVISORY FROM THE JAPAN METEOROLOGICAL AGENCY
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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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