97L gets disrupted by Hispaniola

By: Dr. Jeff Masters , 12:53 PM GMT on July 21, 2010

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A tropical wave (Invest 97L) near the north coast of Hispaniola has been disrupted by interaction with the island, plus the effects of moderate wind shear of 10 - 20 knots. The storm is no longer a threat to develop into a tropical depression today, and the Hurricane Hunter flight that was scheduled for today has been postponed until Thursday. The disturbance has brought heavy rains of 8+ inches to Culebra, Vieques, the Virgin Islands, and some of the northern Lesser Antilles Islands. Wunderblogger Weather456 reported that the power was knocked out on the island of St. Kitts for about 24 hours, due to the intense lightning associated with 97L. All of Puerto Rico and the Virgin Islands are under flash flood watches today.

Satellite images of 97L show a relatively meager number of heavy thunderstorms that are not well-organized. The curved bands to the north and east of the center have disappeared, and there is no evidence of low-level spiral banding or of a surface circulation. Surface observations over the northern Dominican Republic show only light winds, with no westerly winds indicating that a surface circulation is forming. Long-range radar loops from San Juan show a much reduced amount of thunderstorm activity.


Figure 1. Total radar-estimate rainfall for 97L.

Track Forecast for 97L
The storm is in a fairly straightforward steering current environment, and 97L should progress steadily to the west-northwest through Saturday. The rains from 97L's thunderstorms will bring the threat of isolated flooding to the Dominican Republic today, and to Haiti on today and Thursday. Heavy rains from 97L will affect eastern Cuba, the Turks and Caicos Islands, and the eastern Bahamas Thursday, and South and Central Florida can expect heavy rains to arrive Thursday night or Friday morning. The latest suite of model runs from 2am EDT this morning (6Z) foresee 97L making landfall on the Florida coast somewhere between Miami and Cape Canaveral on Friday, then continuing into the Gulf of Mexico on Saturday. Only the Canadian model foresees a threat to Texas, and the other models predict a second landfall between eastern Louisiana and the Florida Panhandle.

Intensity Forecast for 97L
The primary detriment to development of 97L today will be its close proximity to the landmass of Hispaniola. Once the storm pulls away from the island tonight, 97L has a better chance of development. Also hindering development over the next two days will be the presence of dry, stable air in its path over the Bahamas, thanks to the upper-level low to the north of the Dominican Republic. The SHIPS model predicts shear will stay in the moderate range, 10 - 20 knots, over the next three days, which should allow for some steady development of 97L on Thursday and Friday before it reaches Florida. NHC is giving 97L a 60% chance of developing into a tropical depression by Friday, which is a reasonable forecast. I think there is a 70% chance 97L will eventually become Tropical Storm Bonnie, sometime in the next five days. Sudden rapid development before 97L reaches Florida is unlikely, due to the storm's current state of disorganization and the dry air over the Bahamas. It's very unlikely that 97L has time to organize into a hurricane before hitting Florida. I put the odds of 97L making it to hurricane strength before reaching Florida at 5%, and I give a 20% chance it will be a hurricane in the Gulf of Mexico. The probability of 97L being a hurricane in the Gulf of Mexico will depend heavily upon how long the storm spends over water in the Gulf, which is very uncertain. The environment in the Gulf of Mexico should be favorable for intensification, if passage over Florida does not disrupt the storm too much.

I'll have a new post Thursday morning, or earlier if there's a major change to 97L.

Famed climate scientist Steven Schneider dies
Steven Schneider, one of the most influential and talented climate scientists of our time, died on Monday. Ricky Rood has a tribute to Dr. Schneider in today's blog. Ricky comments, "He is known for feistiness. His last book was Science as a Contact Sport: Inside the Battle to Save Earth's Climate. He was a man who was, bluntly, harassed and threatened by those who did not like his message. He never shrank from the battle."

Jeff Masters

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1412. JamesSA
Quoting Orcasystems:
If anyone cares... models are slowly shifting south to Texas... hmmm and we are getting CAT #'s again.



AOI

AOI

AOI

AOI

Landfall Points

TS BUSTED FORECAST ALIBI
That's an UH OH! track.
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1411. Walshy
Area forecast discussion
National Weather Service Blacksburg Virginia
233 PM EDT
Wednesday Jul 21 2010

Models also showing potential disturbance in the tropics making a
track into the Gulf of Mexico this weekend steering it into the
lower MS valley by Sunday-Monday. Moisture will be feeding northward
into this front...
so Monday could be stormy...especially over the
southern extreme County Warning Area.


The pattern looks to linger like this into the end of next week.


&&
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http://weather.noaa.gov/weather/current/MBPV.html
Pressure down to 1011 and 30MPH sustained winds...
97L is developing
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Quoting Orcasystems:
If anyone cares... models are slowly shifting south to Texas... hmmm and we are getting CAT #'s again.



AOI

AOI

AOI

AOI

Landfall Points

TS BUSTED FORECAST ALIBI


Call me when get DOG #'s, I'll be concerned.
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The key is the upper low needs to move FASTER to the west than 97L. Rather, it seems 97L and the upper low are moving westward in tandem, this would keep shearing 97L for a while. The graphics Floodman posted seem to show the upper low in the eastern Gulf of Mexico by 48 hours. I think that would place 97L in southern Florida by that time? That would place 97L in the SE quadrant of the upper low, thus continued SW wind shear.
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Quoting Orcasystems:


Yes, but not a HH


And unlike an HH it will not go into the storm. Only around it.
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Quoting TampaSpin:
Still not happening with 97L yet.....was watching multiple Twist.....the old twist has taken charge again it appears.....so there is really only one spin....at 21.7N 71.7W it just cannot wrap due to the Shear....and dry air....but, with that...it looks somewhat better than it did from 8am this morning Convection wise.


Agree...looks like she will come together in the next few hours.
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with noaa in there they may find a TD or TS



that this a may be
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If anyone cares... models are slowly shifting south to Texas... hmmm and we are getting CAT #'s again.



AOI

AOI

AOI

AOI

Landfall Points

TS BUSTED FORECAST ALIBI
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Quoting ElConando:



Haven't had one of those in a while.


I miss tab cola.
Member Since: June 26, 2006 Posts: 0 Comments: 1115
Quoting 7544:
theres a plane in 97l ? now


Yes, but not a HH
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What ever happen to tornadodude?
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Quoting xcool:
AL, 97, 2010072118, , BEST, 0, 213N, 714W, 30, 1012, DB


97L has resumed a organization trend.. down from 1013 mb.
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Quoting WeatherfanPR:
look SW of the CV Islands.

Link

Nice cyclonic rotation.
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What is that feature in the GOM
it looks good
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1394. 7544
theres a plane in 97l ? now
Member Since: May 6, 2007 Posts: 0 Comments: 6884
1393. JamesSA
Whatever happened to the good old days when kids spent their time out of doors breaking streetlights and vandalizing cars instead of trolling weather blogs?
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Quoting Floodman:


Model COllection and Observed Shear

Ummm, you might want to add this to your favorties, dude


Here's another good one ... studying the 4-panel maps for CMC and GFS can be quite instructive. StormW points people at this site quite often. It's clear from the comments that not too many bother to take him up on the suggestion. Too much like work, or thinking :-)

e-Wall Tropical Atlantic
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Quoting TampaSpin:


Does it kill off those that pretend to be 13 too.......LOL sorry i had to say that ....you all know me!
Tim, stirring the pot early this afternoon?
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1390. NYX
Quoting unf97:


Looking at the visible imagery loop, your estimated center position seems about right. You can see that swirl pretty good on visible, with the convection building N-NE of the swirl, and voiding convection on the S and SW side.


It never fails to amaze me that one can follow a swirl that comes off the coast of Africa all the way across the Atlantic, through some rough neighborhoods and hostile environments and still remain the same swirl that started thousands of miles away. Fortunately for us in SFL this one has managed to outrun convection (so far). Last year there were many of these primarily due to shear tearing off the tops of potential tropical cyclones.
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Quoting FSUstormnut:
Download google earth.. then go to tropicalatlantic.com and click on the reco logo at the top of the page. The file will upload into googleearth and you will have live recon. you can even download all the models as well.. great site...



i have goolg eather thank you for the link


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Quoting nrtiwlnvragn:
The upper level low has started moving westerly at a quicker pace, IMO. If this continues it may have less influence. Note western edge difference from images 3 hours apart.







It was doing this yesterday only to slow down. We'll have to see if the same happens and if it does it could be a pattern for it.
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Quoting Patrap:


I went cheap..


Well, warn a guy, can ya? LOL
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Download google earth.. then go to tropicalatlantic.com and click on the reco logo at the top of the page. The file will upload into googleearth and you will have live recon. you can even download all the models as well.. great site...
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97L is not looking too good right now but it does look better than this morning but that upper level low needs to move out of the way for it to do anything significant consider us lucky here.
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1382. unf97
Quoting Seflhurricane:
going through rough shear now but looks like less ahead


I'm thinking that once the ULL moves farther west during the next 24 hours, shear values should slacken once 97L moves to near the Central Bahamas during the day tomorrow. It is at that time when I believe we will finally see 97L organize enough to close off a COC and be designated a TD. I'm thinking by this time tomorrow afternoon at the earliest.

Recon will confirm it all of course when they investigarte the system tomorrow.
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Quoting Patrap:
I set off a Troll bomb..ya may wanna open da windows


Does it kill off those that pretend to be 13 too.......LOL sorry i had to say that ....you all know me!
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And 72 hours, as it's making the Florida crossing (if it crosses Florida):

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The upper level low has started moving westerly at a quicker pace, IMO. If this continues it may have less influence. Note western edge difference from images 3 hours apart.





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Sometimes the comments about the trolls are just as annoying and disruptive as the trolls themselves. Best to ignore and move on...
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Best time to get some reasoned assessments in the Blog is in the early morning before things get really crazy later in the day.....I tried late at night (post 11:00 PM) a few times but some of the folks posting "appear" to be under the influence of beverages or other substances (especially on Friday and Sat nights) and ready to pounce on you......LOL
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1376. xcool
AL, 97, 2010072118, , BEST, 0, 213N, 714W, 30, 1012, DB
Member Since: September 26, 2009 Posts: 2 Comments: 15705
1375. Patrap
Quoting msgambler:
Trying to save money for Happy Hour are ya?


U betcha..

beats listening to a HOT Mike about Bloggers in Fla..

LOL
Member Since: July 3, 2005 Posts: 434 Comments: 133335
Another Tornado signature on radar close by. 3rd one this YEAR. Crazy for CT. Heading towards Bristol (ESPN)
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Quoting Patrap:


I went cheap..
Trying to save money for Happy Hour are ya?
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Quoting IKE:
From what I see, now that they have adjusted the floater, this may run into northern Cuba...by tomorrow morning unless it changes course....


It isn't moving that fast.
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Quoting FSUstormnut:
Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 21st day of the month at 19:43Z
Aircraft: Gulfstream IV-SP (G-IV) (Reg. Num. N49RF)
Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 07

Part A...

Date: Near the closest hour of 19Z on the 21st day of the month
Highest Mandatory Level For Which Wind Was Reported: 200mb
Coordinates: 28.0N 69.0W
Location: 389 miles (627 km) to the SW (220°) from Hamilton, Bermuda (GBR).
Marsden Square: 079 (About)

Plane now turning south!




link too that
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Projected Shear at 48 hours:

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I know the short-term trend in the last few frames looks impressive. Please, check this visible animation out:

http://www.ssd.noaa.gov/goes/flt/t1/flash-vis.html

During the animation, click on HDW-H check box, that shows upper level winds. This is headed straight into upper level westerly winds on the south side of the upper low. This is beginning to look like an exposed circulation with convection being held back to the east by the upper low. This is a classic wind shear case, and I am still not on board with this one developing. Even if it hasn't developed, its still has brought lots of rain to the northern Caribbean Islands, and next stop for rain is parts of the Bahamas & Turks & Caicos.
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25 kts of shear is strong it can tear the thunderstorms off the center like its doing right now
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Quoting PensacolaDoug:
That was funny. Too bad it had to come off!


What?
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The big picture.
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Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 21st day of the month at 19:43Z
Aircraft: Gulfstream IV-SP (G-IV) (Reg. Num. N49RF)
Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 07

Part A...

Date: Near the closest hour of 19Z on the 21st day of the month
Highest Mandatory Level For Which Wind Was Reported: 200mb
Coordinates: 28.0N 69.0W
Location: 389 miles (627 km) to the SW (220°) from Hamilton, Bermuda (GBR).
Marsden Square: 079 (About)

Plane now turning south!
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look SW of the CV Islands.

Link

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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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