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: 771 - 721

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

max winds are max winds. They are measured by the HH's. You don't have to do math upwards. YOu can subtract from the max on the weak side. They will not list a storm as a cat 1 if someone is going to get cat 2 or 3 winds.
Member Since: Posts: Comments:
Member Since: January 30, 2010 Posts: 0 Comments: 3259
in a weak tropical storm worst waether is typically not right at the center so we might actually get worst weather in extreme S Fl than right at the center as we will be on the dirty side Ne quadrant.
Member Since: August 16, 2008 Posts: 0 Comments: 81
Quoting HoustonTxGal:
It sure is not a good thing that the water temp's in the Gulf are in the mid to upper 80's either.

UGH OH noaa say otherwise for south florida
.SYNOPSIS...TROPICAL DEPRESSION THREE INTENSIFY TONIGHT TO
TROPICAL STORM DRIFT W AT 6 KT AND APPROACH CENTRAL BAHAMAS
TONIGHT AND TO S FLORIDA FRI. ELSEWHERE RIDGE ALONG 31N THROUGH
MON.

$$
Member Since: Posts: Comments:
Quoting chrisdscane:
what time do u guys expect the first few outerbands will reach Sfl ima try to geta round of golf today

I bet you'll be fine until about 4-5pm. After that, you'll be wasting balls.
Member Since: Posts: Comments:
i have google earth.. how do i get to the HH info?>
Member Since: May 30, 2010 Posts: 0 Comments: 111
I still am holding to 90% probability for a hurricane. Too many days over warm water and an upper level low that has already gone ahead of old model forecasts.
Member Since: Posts: Comments:
Quoting gator23:

they will probably shut it down tonight or provide reduced service tommorow. No one should be going to the beaches or Downtown tommorow.


Eh depends on its course it if it stays generally on course or a bit to the north maybe. And how strong it gets as well as the wind field.
Member Since: Posts: Comments:
It sure is not a good thing that the water temp's in the Gulf are in the mid to upper 80's either.
Member Since: Posts: Comments:
Hey El Conando Hemmingways or polydactels are cool cats. have several of them and i live in texas and have friends in the keys that have one of my poly babys and he is huge. not nice to knock the critters because there different. can send pic if you would like!
Member Since: Posts: Comments:
Member Since: Posts: Comments:
man no doubt 98L should be red at the 2 pm update very well organized
Member Since: Posts: Comments:
Quoting gator23:

i think he was referring to the MetroRail not the Tri-Rail


I really don't see either affected tomorrow, but it is a government operation so who knows.
Member Since: Posts: Comments:
Quoting Drakoen:
Some deep convection trying to fire over TD3's center. GOES satellite imagery clouds trying to wrap around the northwest side which is a sign that shear is mitigating.


Indeed. What Lat/Lon do you see the LLC?
Member Since: Posts: Comments:
757. 7544
bahama govmt feels this will become a ts thats why its so far north they issue they own warnings
Member Since: May 6, 2007 Posts: 0 Comments: 6871
Quoting Drakoen:
Some deep convection trying to fire over TD3's center. GOES satellite imagery clouds trying to wrap around the northwest side which is a sign that shear is mitigating.


also just looked at a loop of 98L and you are right, this could be classified today as well, looking impressive
Member Since: Posts: Comments:
755. Chigz
Quoting Jeff9641:


I really think MIA/FLL may get this one. Center seems to be building further north. This is why we need recon info. If I'm wrong so be it as this is only a mere blog.


Where do you live Jeff? Not Miami by any chance?
Member Since: Posts: Comments:
WOW, our Local news/weather.. ABC13 just now sent out a blast text saying there was a TD out there. My they are on the ball!
Member Since: Posts: Comments:
what time do u guys expect the first few outerbands will reach Sfl ima try to geta round of golf today
Member Since: Posts: Comments:
752. RM706
Quoting GetReal:


It would seem that the NHC is calling for a northward turn... It is a matter of where it occurs, and probably how strong of a system this is as it approaches the central GOM.


/sigh ... Are the oil spill ships moving? New Orleans actively talkin gabout this in the local media?
Member Since: Posts: Comments:
I mentioned this yesterday, but will say again.

TD3 (Bonnie) moving WNW over gulf at 16 mph. Winds to the North along the coast prior to landfall will be roughly one category higher than storm intensity rating.

If TD3 (Bonnie) becomes a Cat-1 @ 80 mph wind speed, North eye wall winds will be 96 mph Cat-2. If it has 100 mph Cat-2 sustained winds, North eye wall winds will be 116 mph Cat-3. Fast forward motion tends to make this a stronger storm (although not as long lasting).

Also, keep in mind that the main thrust of the storm surge will be slightly higher than normal along the coast due to the rapid movement of the storm to the WNW. Whatever the category rating... think one category higher with respect to damages at landfall just due to fast forward motion of the storm.

Even if this is projected to be a strong tropical storm... prepare for Cat-1 at landfall just due to fast forward speed.
Member Since: Posts: Comments:
Quoting ElConando:


He meant 3 more cats will be born in key west before it passes. Plenty of em buggers around, descendants of Hemingway's cats. Their like living landmarks.

LMFAO!!!! FTW!
Member Since: Posts: Comments:
000
NOUS42 KNHC 211500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT WED 21 JULY 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 22/1100Z TO 23/1100Z JULY 2010
TCPOD NUMBER.....10-051

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (NORTH OF CUBA)
FLIGHT ONE -- TEAL 70
A. 22/1800Z
B. AFXXX 02BBA INVEST
C. 22/1430Z
D. 23.0N 76.0W
E. 22/1700Z TO 21/2300Z
F. SFC TO 10,000 FT

FLIGHT TWO -- NOAA 49
A. 23/0000Z
B. NOAA9 03BBA SURV
C. 22/1730Z
D. NA
E. NA
F. 41,000 TO 45,000 FT

FLIGHT THREE -- TEAL 71
A. 23/0600Z, 1200Z
B. AFXXX 0403A CYCLONE
C. 23/0300Z
D. 24.5.0N 78.5.0W
E. 23/0500Z TO 23/1200Z
F. SFC TO 15,000 FT

2. SUCCEEDING DAY OUTLOOK: BEGIN 3-HRLY FIXES AT 23/1500Z
IF SYSTEM DEVELOPS. A POSSIBLE G-IV MISSION FOR 24/0000Z
Member Since: Posts: Comments:
Some deep convection trying to fire over TD3's center. GOES satellite imagery clouds trying to wrap around the northwest side which is a sign that shear is mitigating.
Member Since: October 28, 2006 Posts: 57 Comments: 30602
Quoting Abacosurf:

I think it was a replacement cycle. only 5 mph decrease.

I was on Great Guana Cay. It was not weak. 150 mph sustained winds for over 12 hours. 2 plus hour eye passage. Gusts recorded to 221 MPH!!!
Floyd was a kicker. We got cat 2+ winds here in Nassau, 100 miles away.

Hey Abacosurf. Guess u guys are going to get mostly surf from this today...

Quoting jurakantaino:
The only island consider "good size islands are Puerto Rico, Hispaniola, Cuba, the Bahamas don't make any different to a system, to small.
I would add Jamaica to this list... aka the Greater Antilles.
Member Since: October 25, 2005 Posts: 19 Comments: 22561
Quoting GeoffreyWPB:


Do you still stick by your prediction as to the storm going more north as to what the NHC has, as it pertains to southeast Fla?


I really think MIA/FLL may get this one. Center seems to be building further north. This is why we need recon info. If I'm wrong so be it as this is only a mere blog.
Member Since: November 4, 2009 Posts: 0 Comments: 6577
Quoting FLdewey:


Tri-rail is sending all trains to Altoona, PA. The airports are closing at 5pm today. Everyone needs to get below ground now. That thing is a monsta!

i think he was referring to the MetroRail not the Tri-Rail
Member Since: Posts: Comments:
Guess it is a good thing I just stocked up on groceries... Here in my neck of the woods after Ike, all we need is a small gust of wind and we lose power. So if TD3 comes this way... we may be out of lights for a few days. UGH!! and I so love my A/C!
Member Since: Posts: Comments:
742. xcool
Recon yay
Member Since: Posts: Comments:
741. 7544
what time does the plane go in
Member Since: May 6, 2007 Posts: 0 Comments: 6871
I got something from recon now.
Member Since: Posts: Comments:
Quoting A4Guy:


sorry hydrus%u2026comment was directed to allstar17. Apologies.
No problemo .:)
Member Since: Posts: Comments:
Quoting TarheelNMiami:

Nothing from MDT so far. They'll stop the metro at sustained TS force winds, if I remember correctly.

they will probably shut it down tonight or provide reduced service tommorow. No one should be going to the beaches or Downtown tommorow.
Member Since: Posts: Comments:
Quoting GetReal:


It would seem that the NHC is calling for a northward turn... It is a matter of where it occurs, and probably how strong of a system this is as it approaches the central GOM.


Looks like they have it moving quickly, which is probably a Good Thing given the SSTs in that part of the Gulf.
Member Since: Posts: Comments:
Quoting Stormchaser2007:


Cat 3?

Completely unrealistic.



He meant 3 more cats will be born in key west before it passes. Plenty of em buggers around, descendants of Hemingway's cats. Their like living landmarks.
Member Since: Posts: Comments:
<
Quoting Chigz:
I have been a member of this blog for a few years and this year lot of the new members are talking so much CRAP! Please stop...This blog ought to be a little scientific as well as people giving their opinions based on some facts - rather then PURE WISHCASTING...

Glad to folks like StormW, Levi..and others!
**banging table in agreement**
Member Since: Posts: Comments:
weres storm when u need him
Member Since: Posts: Comments:
Quoting Jeff9641:


Sorry buddy I'll tone it down..


Do you still stick by your prediction as to the storm going more north as to what the NHC has, as it pertains to southeast Fla?
Member Since: Posts: Comments:
TD #3 Updates with Video
Member Since: July 5, 2005 Posts: 592 Comments: 29707
Quoting angiest:
Oh yay I'm in the cone.

shouldn;t you be saying, Oh no, i'm in the cone :-(
Member Since: Posts: Comments:
729. A4Guy
Quoting hydrus:
The increase in forward speed I agree with. The forecast as far as strength goes I disagree with. I think there will be a hurricane at some point.
sorry hydrus…comment was directed to allstar17. Apologies.
Member Since: Posts: Comments:
Quoting chrisdscane:


wut have city officials said about public transport and the closing of anything

Nothing from MDT so far. They'll stop the metro at sustained TS force winds, if I remember correctly.
Member Since: Posts: Comments:
Quoting Hurricanes12:


I actually enjoy that they hype things up, lol.


I miss the hysteria of WSVN up here in Tallahassee.
Member Since: Posts: Comments:
nice blowup right where center should be at. keep watching
Link
Member Since: Posts: Comments:
Quoting gator23:

I am now a JEFFCASTER, anything he says I go with. He has been right about two differnt tropical systems. The self stroking is geting annoyng though imo.


Remember, even a broken clock is right twice a day. You can call the NWS in Melbourne and even they will tell you that.
Member Since: Posts: Comments:
Quoting chrisdscane:


wut have city officials said about public transport and the closing of anything

they said we dont handle public transportation the county does call them.
WSVN will tell you watch them
Member Since: Posts: Comments:
723. Chigz
I have been a member of this blog for a few years and this year lot of the new members are talking so much CRAP! Please stop...This blog ought to be a little scientific as well as people giving their opinions based on some facts - rather then PURE WISHCASTING...

Glad to folks like StormW, Levi..and others!
Member Since: Posts: Comments:
Quoting clwstmchasr:


You said you talked with the Melbourne WS (which none of us believed)and they told you to expect 4-5 inches of rain in Central FL. That was your forecast.


You must be quoting someone else because they said 2 to 3" and that is what i posted. Is there something wrong with the NWS saying to 2 to 3" rain event. Come on Man!! If you don't like my post that's fine but don't fabricate them PLEASE!!!!
Member Since: November 4, 2009 Posts: 0 Comments: 6577
NEXRAD Radar
Miami, Base Reflectivity 0.50 Degree Elevation Range 248 NMI

Member Since: Posts: Comments:

Viewing: 771 - 721

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

Overcast
47 °F
Overcast