Tropical depression forming over the Bahamas

By: Dr. Jeff Masters , 1:29 PM GMT on July 22, 2010

Share this Blog
0
+

A tropical wave (Invest 97L) over the eastern Bahama Islands has developed a closed circulation at the surface, and has become a tropical depression or tropical storm. Here is the text of the Special Tropical Weather Outlook from NHC at 8:25am EDT today:

Visible satellite images and observations from the Bahamas indicate that the area of low pressure in the southeastern Bahamas has become better organized and a closed circulation has formed. Advisories on a tropical depression or a tropical storm will be initiated at 11 am EDT...1500 UTC today. This advisory will likely include tropical storm watches and warnings for portions of the Bahamas and southern Florida.

Satellite images of 97L show a modest area of heavy thunderstorms that have slowly increased in intensity and areal coverage this morning. Water vapor satellite loops show a large area of dry air lies to the west of 97L, over Florida. This dry air is associated with a large upper-level low pressure system that is moving west at about the same speed 97L is. The counter-clockwise flow of air around the upper low is bringing about 20 knots of wind shear to 97L. Surface observations in the Bahamas and several nearby ships have shown top winds in 97L of up to 35 mph, so the storm is close to the 40 mph winds needed to be classified as a tropical storm.


Figure 1. Water vapor satellite image showing dry air (brown colors) associated with the upper-level low over Florida. Image credit: NOAA/NESDIS.

Track Forecast for 97L
The storm is in a fairly straightforward steering current environment, and 97L should progress steadily to the west to west-northwest through Saturday. This will bring the storm ashore over the Florida Keys or South Florida on Friday, and into the Gulf of Mexico on Saturday. The latest set of model runs from 2am EDT (6Z) had the advantage of having data from a flight of the NOAA jet last night, so we have higher confidence than usual in the track of 97L over the next two days. The location of 97L's final landfall along the Gulf of Mexico coast has the usual uncertainties for 3 - 4 days, with the various models calling for landfall somewhere between the upper Texas coast and the Florida Panhandle coast. Given the uncertainties, the move halt operations in the Deepwater Horizon blowout recovery effort are probably wise.

Intensity Forecast for 97L
The primary detriment to development of 97L for the next three days will be the presence of the large upper-level low to its west. As long as this low remains in its present location, relative to 97L, it will bring wind shear of about 20 knots and dry air into the storm. This will limit the intensification potential of 97L to no more than about 10 - 20 mph per day. If the upper-level low picks up speed and pulls away from 97L, the storm may be able to intensify at a faster rate. None of the computer models is calling for that to happen, but it is possible. I put the odds of 97L making it to hurricane strength in the Gulf of Mexico at 20%.

98L
An area of disturbed weather (98L) has developed in the Gulf of Mexico's Bay of Campeche. This system is under a low amount of shear, 5 - 10 knots, and may barely have enough time to organize into a tropical depression before making landfall along the Mexican coast a few hundred miles south of the Texas border on Friday.

I'll have an update after NHC releases their 11am advisory package.

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: 121 - 71

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17Blog Index

121. 7544
all we need are the plots now stay tuned
Member Since: May 6, 2007 Posts: 0 Comments: 6707
Its easier to watch a storm develop and strengthen when the models are not clustered right over you lol
Member Since: August 29, 2006 Posts: 22 Comments: 1342
Quoting WINDSMURF:
Hopefully it will miss florida completely. Any one of you experts believe that it may actually go a little north and impact the metro area in Miami?


Depends what you mean by 'impact', of course. The eye/CoC passing directly over Miami? That's a small target for such a big system, so chances of that aren't very good. But if you mean lots of rain and lots of wind--many hours' worth--then most likely yes.
Member Since: Posts: Comments:
Quoting whs2012:
Will the NHC come out with the cone of uncertainty around 11PM CST or EST?


On TD3, NHC goes based on ET. Based on the previous info provided by them on 97L... yes there will be graphical tracks and impacts being issued by 11AM ET
Member Since: Posts: Comments:
Quoting WINDSMURF:
Hopefully it will miss florida completely. Any one of you experts believe that it may actually go a little north and impact the metro area in Miami?


looking at the shape of it now... looks like all the rain will be on the right, the fla side, unless it starts being a different shape. i am not janice-stradamas
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Storm, I have a question for you.

The ULL seems to be moving WSW. If it dends up a bit south and west of TD3, can it provide a nudge to the north for TD3 if it becomes a TS ? Also what will it provide in terms of ventilation depending upon its relative position to TD 3?
Member Since: Posts: Comments:
Looks like TD3 has building some convection in its northwestern quadrant. Also looks to have slowed down some.
GOES satellite animation
Member Since: October 28, 2006 Posts: 57 Comments: 29942
Thank you Doc and Storm as always
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting Jeff9641:


The coc is north of the model plots at 8am due to bad info from last night. COC appears like it will go anywhere from FLL to Marathon Key. Also people in Tampa this will not be be too far to the south of you so 25 to 35mph winds and heavy rain with totals of 2 to 4" from Fri thru Sat.


Jeff, I honestly don't see that. The LMWA's just don't support that drastic of an impact in Tampa, the HPC's FIVE day total is only about 1 inch to 1.25 inches in the Tampa area.. I'd temper the warnings just a bit, IMO. The 12Z BAM models (Which have been more accurate with 97L than any others) did have the correct initial coordinates of 21.6N, 74.4W at the time.

Member Since: Posts: Comments:
Okay, let's try a simple plea.

Storm has been wrong, and Doc masters, and Levi and Pat and 456 and etc.... It happens.

We now have a storm headed our way that will be a concern and a danger to life, limb and property.

Could we reserve this space for that and save the backbiting for when you all have just nothing better to do?

Please?

Cool...and oh yeah better mention this, I have been wrong too :-)
Member Since: Posts: Comments:
Quoting Chucktown:
Just remember - the current track is a worst case scenario right now for the oil slick. If Bonnie were to make landfall near the TX/LA border, the slick will be right there in the NE onshore quadrant, regardless if it is a storm or minimal hurricane. Believe it or not, they are better off with the storm making a direct hit to "minimize" the surge a bit.


You might be right about that......
Member Since: Posts: Comments:
Quoting CybrTeddy:
Well now we know what will be the top story on the local news at 5 pm today.


Actually.. when it gets a new designation @11, they probably wont go off the air
Member Since: Posts: Comments:
Shear doesn't look like it will be an issue at least according to this map:

Larger version
Member Since: Posts: Comments:
twcracker patrap gave us this link last night



http://raleighwx.easternuswx.com/models/atcfstorm1.html
Member Since: June 28, 2009 Posts: 0 Comments: 156
102. CJ5
Quoting IKE:


See post #40.


Ike, how are things in LA? I will be driving through on the way to Destin next week. Thankfully, I got the hurricane insurance but I would rather go on vacation. Maybe, with some luck, I can.
Member Since: Posts: Comments:
The intensity of this one willl be easy to monitor, watch the WV loops to see what is happening with all that dry dry air.
Member Since: Posts: Comments:
Well now we know what will be the top story on the local news at 5 pm today.
Member Since: Posts: Comments:
Quoting whs2012:
Will the NHC come out with the cone of uncertainty around 11PM CST or EST?


est
Member Since: Posts: Comments:
Quoting StormW:
97L / 98L SYNOPSIS ISSUED 9:30 A.M. JULY 22, 2010


Thanks Storm -
Member Since: Posts: Comments:
Just remember - the current track is a worst case scenario right now for the oil slick. If Bonnie were to make landfall near the TX/LA border, the slick will be right there in the NE onshore quadrant, regardless if it is a storm or minimal hurricane. Believe it or not, they are better off with the storm making a direct hit to "minimize" the surge a bit.
Member Since: Posts: Comments:
i am just warning everyone tho... the other day i was feeling weirdly anxious so I sat down at the computer with a huge thirst buster size 64 ox triple latte and googled what causes anxiety and the first on the list was "excessive amounts of caffeine". so maybe lay off the caffeine when a storm is coming. nah. gotta stay awake and not miss anything haha!
Member Since: Posts: Comments:
Quoting CaribBoy:
Tropical cyclone heading towards South floridia... I can't imagine how this blog will look like!

*getting out the popcorn and drinks*
Member Since: Posts: Comments:
I dont think this system will make landfall in S.Fl. I may be wrong though.
Member Since: Posts: Comments:
Quoting Jeff9641:


The coc is north of the model plots at 8am due to bad info from last night. COC appears like it will go anywhere from FLL to Marathon Key. Also people in Tampa this will not be be too far to the south of you so 25 to 35mph winds and heavy rain with totals of 2 to 4" from Fri thru Sat.


I have mucho respect for the NHC but, I have to say, last night I wanted to call the 2am forecaster and ask him what the He** are you looking at, 40%?
Member Since: Posts: Comments:
Quoting BahaHurican:
Wow a due NW heading for TD3 would bring the centre right over New Providence... in about 25-30 hours... LOL

I'll take W or WNW for a lot of money, ta.


that is something to really watch if the High is really strong then a more westerly component should begin.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
9:40 AM EDT - About 9 minutes old.



Very nice shape to her now.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
9:40 AM EDT - About 9 minutes old.

I would put the LLC of 03L between Mayaguara Island and Acklins Island.

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Hopefully it will miss florida completely. Any one of you experts believe that it may actually go a little north and impact the metro area in Miami?
Member Since: Posts: Comments:
Quoting StormW:


MODELS (UNDER TROPICAL MODELS ATCF)


wow that is a great website. i saved it under my "emergency management" file :) Looks like NOLA tho... maybe things have been fixed enough there to handle it tho. I will think hopeful thoughts for wherever it goes!
Member Since: Posts: Comments:
This thing isnt that big, thats for sure

Smaller rotations do tend to ramp up and organize a little quicker

Not saying it will btw
Member Since: Posts: Comments:
Quoting extreme236:
hurrkat05 is never right anyway. If you listen to him you get what you deserve.


He/she is probably stormkat.
Member Since: Posts: Comments:
10 am central ..... bonnie and colin ..... will the high pressure force this bahamas storm more west .... port o'conner to port arthur...? shouldn't this be bonnie and clyde....
Member Since: Posts: Comments:
Member Since: October 28, 2006 Posts: 57 Comments: 29942
78. 7544
its not moving again just spining
Member Since: May 6, 2007 Posts: 0 Comments: 6707
Wow a due NW heading for TD3 would bring the centre right over New Providence... in about 25-30 hours... LOL

I'll take W or WNW for a lot of money, ta.
Member Since: October 25, 2005 Posts: 19 Comments: 21668
Quoting CaribBoy:
Tropical cyclone heading towards South floridia... I can't imagine how this blog will look like!


It won't be as crazy as a Cat 5 hitting s fL (or Andrew)
Member Since: Posts: Comments:
9:40 AM EDT - About 9 minutes old.

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Having some troubles posting images...but wow. TD 3 is looking impressive. Link
Member Since: Posts: Comments:
Tropical cyclone heading towards South floridia... I can't imagine how this blog will look like!
Member Since: Posts: Comments:
Its unbelievable, around this time yesterday it was poorly disorganized, now I wake up to a TD.
Member Since: Posts: Comments:

Viewing: 121 - 71

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17Blog 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
62 °F
Mostly Cloudy