Tropical Depression Two forms from Invest 98L

By: Dr. Jeff Masters , 9:33 PM GMT on July 17, 2011

Share this Blog
0
+

Tropical Depression Two (TD2) formed from Invest 98L this afternoon. Hurricane Hunters flew into the suspect area and found a surface circulation north of the Bahamas, with maximum sustained winds of 35 mph. They also determined the system had become warm core—a characteristic that must be present in order to declare a tropical cyclone. Satellite imagery continues to show the system is becoming more organized with a stronger circulation. Wind shear is forecast to remain favorable for the system until Tuesday or Wednesday when higher shear will slide in from the north. Sea surface temperatures are warm enough to sustain a tropical storm.


Figure 1. Satellite imagery of Tropical Depression Two in the Atlantic, east of Florida. This graphic will update to the current satellite imagery.


Figure 2. Official 5-day forecast for Tropical Depression Two. This graphic will remain current.

Forecast for TD2

The models are coming into better agreement as TD2 has become more organized. In terms of dynamical forecast models, the HWRF and GFS both forecast TD2 to max out just above tropical storm strenth. HWRF intensifies TD2 to around 47 mph in the next 24 hours, whereas GFS is a bit slower to bring the system up to tropical storm status. Two statistical models, the DSHP (SHIPS model that includes land interaction) and the LGEM (Logistical Growth Equation Model) both intensify TD2 to a moderate tropical storm over the next 2-3 days.

There tends to be a lot of uncertainty involved with tropical cyclones that form under these circumstances, but our forecast remains in line with the National Hurricane Center and the reliable forecast models. TD2 will move slowly to the northeast in weak steering currents over the next few days before eventually becoming an extratropical storm. There is minimal chance that this system will cross over Florida into the Gulf of Mexico. Timing and path depend heavily on how intense the cyclone gets, as Jeff mentioned in his blog earlier today. A weaker storm will tend to stay south, whereas a stronger storm will grow taller in the atmosphere and winds at higher levels will influence it and steer it northeast.

None of the reliable models predict tropical cyclone development over the remainder of the Atlantic through July 23.

Angela

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: 825 - 775

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 | 25Blog Index

45mph? Not sure if serious...LOL.
Member Since: Posts: Comments:
I'm seeing an eyewall form, no?
Member Since: Posts: Comments:
Cross-section of the center from N-S.

FULL IMAGE

Member Since: Posts: Comments:
45 MPH storm now
Member Since: July 22, 2010 Posts: 6 Comments: 752
000
WTNT32 KNHC 180547
TCPAT2

BULLETIN
TROPICAL STORM BRET INTERMEDIATE ADVISORY NUMBER 2A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
200 AM EDT MON JUL 18 2011

...BRET A LITTLE STRONGER...TROPICAL STORM WARNING ISSUED FOR PART
OF THE NORTHWEST BAHAMAS...


SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...27.1N 78.0W
ABOUT 75 MI...120 KM NW OF GREAT ABACO ISLAND
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...SSE OR 155 DEGREES AT 4 MPH...6 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A TROPICAL STORM WARNING
FOR GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST
BAHAMAS.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST BAHAMAS

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN THE
NEXT FEW HOURS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 AM EDT...0600 UTC...THE CENTER OF TROPICAL STORM BRET WAS
LOCATED BY AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT NEAR
LATITUDE 27.1 NORTH...LONGITUDE 78.0 WEST. BRET IS MOVING TOWARD
THE SOUTH-SOUTHEAST NEAR 4 MPH...6 KM/H...HOWEVER A TURN TOWARD THE
NORTH-NORTHEAST IS EXPECTED ON MONDAY.

DATA FROM THE AIRCRAFT INDICATE THAT MAXIMUM SUSTAINED WINDS HAVE
INCREASED TO NEAR 45 MPH...75 KM/H...WITH HIGHER GUSTS. SOME
ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT DAY OR SO.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM
FROM THE CENTER.

THE LATEST MINIMUM CENTRAL PRESSURE MEASURED BY THE HURRICANE HUNTER
AIRCRAFT WAS 1002 MB...29.59 INCHES.


HAZARDS AFFECTING LAND
----------------------
RAINFALL...BRET COULD PRODUCE TOTAL RAINFALL AMOUNTS OF 2 TO 4
INCHES OVER THE NORTHWEST BAHAMAS.

WIND...TROPICAL STORM CONDITIONS ARE ONGOING OR IMMINENT IN THE
WARNING AREA...AND ARE EXPECTED TO CONTINUE THROUGH MONDAY.

SURF...LOCALLY HIGH SURF CONDITIONS CAN BE EXPECTED ALONG NORTHERN
AND WESTERN FACING BEACHES IN THE NORTHWEST BAHAMAS THROUGH MONDAY.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 AM EDT.

$$
FORECASTER BRENNAN
Member Since: Posts: Comments:
Some hot waters...

Member Since: Posts: Comments:
Quoting Stormchaser2007:
This is why I like the night shift...
me too.

night shift is more relaxed, calm, and quiet
Member Since: Posts: Comments:
NHC taking there time on their 2am update, don't know how they are going to explain these readings.
Member Since: Posts: Comments:
now the hurricane season getting interesting! Finally something to talk about. Bret seems really impressive on radar. I wonder if it has a chance to get the first hurricane of the season.
Member Since: Posts: Comments:
Still continues to chug SSE according to recon/radar.

May extend the time it has to strengthen.
Member Since: Posts: Comments:
Wow, I'm amazed. These reports have made my jaw drop.
Member Since: Posts: Comments:
Live in Dania beach area just south of ft lauderdale and got hit with pretty hard rains this evening and they said was not associated with bret but i look at the radar and it seems like that was the tail....
Member Since: Posts: Comments:
So this has moved a lot farther south than the NHC said, can that affect the track from here on out? whether it feels the weakness?
Member Since: Posts: Comments:
Quoting Skyepony:
I'm floored by that temp dif inside & out.
Skye, you think were seeing the beginnings of an eye? I noticed the same thing.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
809. Skyepony (Mod)
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 18th day of the month at 05:35Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 308)
Storm Number & Year: 02L in 2011
Storm Name: Bret (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 04
A. Time of Center Fix: 18th day of the month at 5:12:20Z
B. Center Fix Coordinates: 27°09'N 77°59'W (27.15N 77.9833W) (View map)
B. Center Fix Location: 132 miles (212 km) to the ENE (77°) from West Palm Beach, FL, USA.
C. Minimum Height at Standard Level: 1,454m (4,770ft) at 400mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 49kts (~ 56.4mph)
E. Location of the Estimated Maximum Surface Wind: 5 nautical miles (6 statute miles) to the NW (310°) of center fix
F. Maximum Flight Level Wind Inbound: From 48° at 43kts (From the NE at ~ 49.5mph)
G. Location of Maximum Flight Level Wind Inbound: 8 nautical miles (9 statute miles) to the NW (316°) of center fix
H. Minimum Sea Level Pressure: 1002mb (29.59 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 15°C (59°F) at a pressure alt. of 1,462m (4,797ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 1,473m (4,833ft)
K. Dewpoint Temp & Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 400mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 5 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 43kts (~ 49.5mph) in the northwest quadrant at 5:09:40Z
Maximum Flight Level Wind Outbound: 51kts (~ 58.7mph) in the southeast quadrant at 5:16:40Z
Remarks Section - Additional Remarks...
Banding North and East on radar
Member Since: August 10, 2005 Posts: 227 Comments: 39445
Latest frame of IR at 0531Z shows a possible hot tower starting to fire just N of the center. If this expands, intensification should easily continue.
Member Since: Posts: Comments:
i live in ft lauderdale no chqnce of it coming this way right still heading north and then northeast right?
Member Since: Posts: Comments:
806. Skyepony (Mod)
I'm floored by that temp dif inside & out.
Member Since: August 10, 2005 Posts: 227 Comments: 39445
Member Since: Posts: Comments:
Quoting Stormchaser2007:
This is why I like the night shift...
And the environment on the blog is so calm. No 3 letter trolls.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Bret has been intensifying approximately 1 millibar an hour. Could justify what appears to be an eyewall developing on radar imagery.
I was thinking this too, but the VDM made no mention of this.
Member Since: Posts: Comments:
1002 MB: 50 MPH winds at least
Member Since: July 22, 2010 Posts: 6 Comments: 752
This is why I like the night shift...
Member Since: Posts: Comments:
Bahamas need TS warnings ASAP.
Member Since: Posts: Comments:
Bret has been intensifying approximately 1 millibar an hour. Could justify what appears to be an eyewall developing on radar imagery.
Member Since: Posts: Comments:
Quoting Stormchaser2007:
Low-level spiral bands are developing near the COC according to radar.


000
URNT12 KNHC 180535
VORTEX DATA MESSAGE AL982011
A. 18/05:12:20Z
B. 27 deg 09 min N
077 deg 59 min W
C. 400 mb 1454 m
D. 49 kt
E. 310 deg 5 nm
F. 048 deg 43 kt
G. 316 deg 8 nm
H. 1002 mb
I. 15 C / 1462 m
J. 21 C / 1473 m
K. NA / NA
L. NA
M. NA
N. 12345 / 4
O. 0.02 / 5 nm
P. AF308 0202A BRET OB 04
MAX FL WIND 43 KT NW QUAD 05:09:40Z
MAX OUTBOUND FL WIND 51 KT SE QUAD 05:16:40Z
Banding North and East on radar
Member Since: Posts: Comments:
and its moved about 25 miles SSE from this afternoon
Member Since: September 18, 2010 Posts: 0 Comments: 5248
Quoting Stormchaser2007:
Tops way up to 50kft!



Let's see what they find in the NE quadrant. Wow I must admit I did not see this coming.
Member Since: Posts: Comments:
Interesting reports coming in from Hurricane Hunters. This is why real-time data is so much more valuable than satellite data. Gotta love the hunters...
Member Since: Posts: Comments:
Tops way up to 50kft!



Member Since: Posts: Comments:
Will be interesting to see what the remarks are on the VDM.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
791. Skyepony (Mod)
Dropsonde came in with 1002mb..
Member Since: August 10, 2005 Posts: 227 Comments: 39445
Pressure down to 1002mbs according to the sonde.
Member Since: Posts: Comments:
Holy crap.... 1002 mb.... thats a big drop.
Member Since: Posts: Comments:
Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 18th day of the month at 05:26Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 308)
Storm Number: 02
Storm Name: Bret (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 05

Part A...

Date: Near the closest hour of 5Z on the 18th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 27.1N 78.0W
Location: 130 miles (209 km) to the ENE (78°) from West Palm Beach, FL, USA.
Marsden Square: 080 (About)

Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1002mb (29.59 inHg) Sea Level (Surface) 27.6°C (81.7°F) 25.2°C (77.4°F) 225° (from the SW) 9 knots (10 mph)
1000mb 21m (69 ft) 27.4°C (81.3°F) 25.1°C (77.2°F) 225° (from the SW) 10 knots (12 mph)
925mb 709m (2,326 ft) 22.2°C (72.0°F) 21.4°C (70.5°F) 230° (from the SW) 11 knots (13 mph)
850mb 1,447m (4,747 ft) 20.4°C (68.7°F) Approximately 14°C (57°F) 270° (from the W) 10 knots (12 mph)

Information About Radiosonde:
- Launch Time: 5:12Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...

Dropsonde Location: Dropped in eye.

Splash Location: 27.14N 77.97W
Splash Time: 5:14Z

Release Location: 27.14N 77.97W
Release Time: 5:12:29Z

Splash Location: 27.14N 77.97W
Splash Time: 5:14:17Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 235° (from the SW)
- Wind Speed: 10 knots (12 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 235° (from the SW)
- Wind Speed: 8 knots (9 mph)
- Depth of Sounding: From 849mb to 1002mb

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 158 gpm - 8 gpm (518 geo. feet - 26 geo. feet)
- Wind Direction: 230° (from the SW)
- Wind Speed: 10 knots (12 mph)

Sounding Software Version: AEV 20802

Part B: Data For Significant Levels...

Significant Temperature And Relative Humidity Levels...
Level Air Temperature Dew Point
1002mb (Surface) 27.6°C (81.7°F) 25.2°C (77.4°F)
927mb 22.2°C (72.0°F) 21.5°C (70.7°F)
904mb 23.4°C (74.1°F) 18.7°C (65.7°F)
850mb 20.4°C (68.7°F) Approximately 14°C (57°F)
849mb 20.2°C (68.4°F) Approximately 14°C (57°F)

Significant Wind Levels...
Level Wind Direction Wind Speed
1002mb (Surface) 225° (from the SW) 9 knots (10 mph)
917mb 235° (from the SW) 11 knots (13 mph)
885mb 235° (from the SW) 4 knots (5 mph)
862mb 260° (from the W) 4 knots (5 mph)
849mb 270° (from the W) 11 knots (13 mph)
The highest wind observed in the "Significant Wind Levels" section is noted in bold.

lol, anyway its already down to 1002 mb.
Member Since: Posts: Comments:
787. JLPR2
Quoting wolftribe2009:
GFS is showing TWO lows coming off Africa. One around 300 Hours and one 384 Hours

300 Hours
Link

384 Hours
Link


The 00zGFS also shows a decent vort entering the Caribbean from the TW that is around the Cape Verde islands; but dissipates it soon afterwards.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Quoting Stormchaser2007:


and eye..................LOLOLOLOL
Member Since: September 18, 2010 Posts: 0 Comments: 5248
50's and 60's in the thunderstorm
Member Since: September 18, 2010 Posts: 0 Comments: 5248
Time: 05:10:00Z
Coordinates: 27.2333N 78.0833W
Acft. Static Air Press: 849.6 mb (~ 25.09 inHg)
Acft. Geopotential Hgt: 1,479 meters (~ 4,852 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 43° at 41 knots (From the NE at ~ 47.1 mph)
Air Temp: 15.7°C* (~ 60.3°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 43 knots (~ 49.4 mph)
SFMR Peak (10s) Sfc. Wind: 47 knots (~ 54.0 mph)
SFMR Rain Rate: 3 mm/hr (~ 0.12 in/hr)
(*) Denotes suspect data
Member Since: September 18, 2010 Posts: 0 Comments: 5248
Why no extrap. pressure readings?
Member Since: Posts: Comments:
782. JLPR2
Quoting sunlinepr:

Tomorow I'll go and buy the front door "Tormenteras" that I'm missing... (including the pampers)


I would have raid Home Depot I'm missing the storm shutters off everything. :\
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Note:

They are flying at the 850mb level.
Member Since: Posts: Comments:
780. Skyepony (Mod)
Recon hit center ~27.150N 78.000W.
Member Since: August 10, 2005 Posts: 227 Comments: 39445
Quoting SouthDadeFish:
Some of the SFMR readings may be inaccurate due flying over shallow waters/land. The 51 knot flight level wind is impressive though.


The winds have not been flagged as suspect, though.
Member Since: June 29, 2009 Posts: 13 Comments: 5315
Quoting PrivateIdaho:
sure questionable moves can occur but the type of conspiracy you are postulating would require everyone from the H.H. to the director of the NHC to be falsifying data.....not happening.
I once knew an ER Doctor. Very ethical ,etc. BUT this CLOWN administrator would pass by the ER every so often and say "we need to get admits up to 20%. XYZ Hospital down the road admits 23% of their ER visits. Maybe you guys are not being careful enough." And so he admitted more.

BTW, louisiana seafood never tasted better. I recommend the fried trout right now.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
ime: 05:09:30Z
Coordinates: 27.2667N 78.1W
Acft. Static Air Press: 849.0 mb (~ 25.07 inHg)
Acft. Geopotential Hgt: 1,493 meters (~ 4,898 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 48° at 41 knots (From the NE at ~ 47.1 mph)
Air Temp: 14.5°C* (~ 58.1°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 43 knots (~ 49.4 mph)
SFMR Peak (10s) Sfc. Wind: 53 knots (~ 60.9 mph)
SFMR Rain Rate: 13 mm/hr (~ 0.51 in/hr)
(*) Denotes suspect data

Not suspect data?
Member Since: Posts: Comments:
Some of the SFMR readings may be inaccurate due flying over shallow waters/land. The 51 knot flight level wind is impressive though.
Member Since: Posts: Comments:

Viewing: 825 - 775

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 | 25Blog 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

Mostly Cloudy
38 °F
Mostly Cloudy

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron