97L a threat to become a tropical depression on Wednesday

By: Dr. Jeff Masters , 1:31 PM GMT on July 20, 2010

Share this Blog
3
+

A tropical wave (Invest 97L) near the east coast of Puerto Rico has become more organized overnight and is a threat to develop into a tropical depression as early as Wednesday. The disturbance has brought heavy rains of 8+ inches to Culebra and Vieques islands over the past day (Figure 1), and all of Puerto Rico and the Virgin Islands are under flash flood watches today. The storm could bring an additional 3 - 6 inches of rain to the islands over the next two days. The upper level low centered a few hundred miles north of the Dominican Republic is no longer bringing high levels of wind shear to 97L; wind shear has fallen to the moderate range, 10 - 20 knots, which may allow 97L to continue to develop today. Satellite images of 97L show a moderate area of disorganized thunderstorms, but no signs of a surface circulation, no low-level spiral banding, and no upper-level outflow. There is a large amount of dry air to the northwest of Puerto Rico that will interfere with development of 97L. Surface observations show only light winds over Puerto Rico, with no signs of a surface circulation. The Hurricane Hunters are on call to investigate 97L this afternoon, if necessary.


Figure 1. Total radar-estimated rainfall from Invest 97L.

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 flooding to the Dominican Republic today and Wednesday, and to Haiti on Wednesday and Thursday. Heavy rains from 97L will begin moving into eastern Cuba, the Turks and Caicos Islands, and the eastern Bahamas on Wednesday, and South Florida can expect heavy rains to arrive as early as Thursday night. We do have several models developing 97L into a tropical depression or tropical storm. The GFS and HWRF both take 97L to tropical storm status over the Bahamas by Thursday, with the storm then tracking over South Florida on Friday and entering the Gulf of Mexico on Saturday. The NOGAPS is similar, but portrays a weaker system. All of these models foresee a threat to the oil spill region by Saturday night or Sunday, with the storm making a second landfall somewhere between the Florida Panhandle and Louisiana. One factor potentially aiding the storm will be the Madden-Julian oscillation, which currently favors upward motion over the Gulf of Mexico and Caribbean. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased. Also in favor of development are the warm ocean temperatures of 29°C. The SHIPS model predicts shear will remain moderate, 10 - 20 knots, over the next 4 - 5 days, and I believe the primary detriment to development of 97L 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. NHC is giving 97L a 40% chance of developing into a tropical depression by Thursday, which is a reasonable forecast. I think there is a 60% chance 97L will eventually become Tropical Storm Bonnie, sometime in the next five days. Sudden rapid development today or on Wednesday is unlikely, due to the dry air over the Bahamas, and I put the odds of 97L making it to hurricane strength before reaching Florida at 10%. There is a better chance that 97L could attain hurricane strength in the Gulf of Mexico, perhaps 20%. These probabilities will depend heavily upon how long 97L (or Bonnie) spends over land or interacting with land over the next four days, which is very uncertain.

Time to cut the forecast numbers for the coming hurricane season?
Here are the number of Atlantic named storms, hurricanes, and intense hurricanes predicted by the various forecast groups in their late May or early June forecasts:

23 named storms: PSU statistical model
20 named storms: UKMET GloSea dynamical model
18.5 named storms, 11 hurricanes, 5 major hurricanes: NOAA hybrid statistical/dynamical model technique
18 named storms, 10 hurricanes, 5 intense hurricanes: CSU statistical model (Phil Klotzbach/Bill Gray)
17.7 named storms, 9.5 hurricanes, 4.4 intense hurricanes: Tropical Storm Risk (TSR), hybrid statistical/dynamical model technique (Note: TSR increased their numbers to 19.1, 10.4, and 4.8 with their July 6 forecast)
17 named storms, 10 hurricanes: FSU dynamical model
10 named storms, 6 hurricanes, 2 intense hurricanes: climatology

The group forecasting the lowest activity was the Florida State University group led by Dr. Tim LaRow. They use a new dynamical forecast model called COAPS, which is funded by a 5-year, $6.2 million grant from NOAA. This year's June forecast by the COAPS model called for 17 named storms and 10 hurricanes. However, Dr. LaRow emailed me yesterday to say that the COAPS model is now calling for reduced activity. Using the state of the atmosphere and ocean as of July 15, a new run of the COAPS model was performed over the weekend. The new forecast is now calling for two fewer hurricanes--a total of 15 named storms and 8 hurricanes (including Alex.) The COAPS model generated an "ensemble" of five different forecasts, done by varying the initial sea surface temperatures by a few percent at the beginning of the model run. These five forecasts came up with a range of 12 - 16 named storms (including Alex), and 7 - 10 hurricanes. It will be interesting to see when CSU issues its August 4 forecast if they also cut their numbers. With only one named storm (Alex) thus far this year, it's getting pretty hard to have a season with 19 or 20 named storms. Only four hurricane seasons since 1851 have had as many as nineteen named storms. These four seasons--1887, 1933, 1995, and 2005--all had at least three named storms by July 20.

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on my blog during the show. You can also email the questions to me today before the show: jmasters@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line. Some topics I'll cover today on the show:

1) Invest 97
2) A look ahead at the coming two weeks

Today's show will be about 45 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

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: 288 - 238

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 | 25 | 26 | 27Blog Index

Quoting MiamiHurricanes09:


What is that wave right under the dominican rep.
doing? It's been there for a while now
Member Since: July 20, 2010 Posts: 0 Comments: 225
Good morning, Dr. M. gives 97L 60% chance of becoming Bonnie with it maybe crossing south Florida as a tropical storm/depression and then entering the gulf sometime around Saturday. Rapid intensification, he says, is unlikely.
Is banding currently starting to form to its north side?
Caribbean - Rainbow Loop
Member Since: Posts: Comments:
285. unf97
You beat me to the punch LOL.. I was just getting ready to post that as well. Yeah, that wave emerging now off the African coast looks very vigorous. If the SAL has decreased, that system could be our first Cape Verde cyclone this season. Definitely something to watch.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting BahaHurican:
You know, there's really not enough going on with this system right now to justify calling it a "nasty storm". I myself am not seeing sufficient justification for even a highend cat one before it hits FL [not yet, anyway]. Let's not err on the side of the hyperbolic and possibly even ridiculous. Right now this is more of a "do you know where your shutters are" situation and less of a "batten up your houses now, quiet storm is coming down" one...

Peace [not pieces] everyone. Gotta run...


Baha, logic rarely cames in to play on this blog, you know that......
Member Since: September 1, 2007 Posts: 0 Comments: 1793
Apparently 97L developing an area of low pressure (1011mb).

Member Since: September 2, 2009 Posts: 130 Comments: 21032
Member Since: July 20, 2010 Posts: 0 Comments: 225
281. beell
06Z GFS 200mb
Valid 06Z Thursday (48 hrs)


Link
Member Since: Posts: Comments:
Quoting twhcracker:


when i was a kid growing up in fla on a bayou, hurricanes were such fun. As a kid, had no worries, we got to stay up all night with hurricane lanterns, my dad would tell scarey stories, my mom would give us peanut butter sandwiches in the middle of the night, no school the next day, and we were too young and dumb to know there was something to fear. i remember walking out onto our porch during the eye of a storm and the yard was full of limbs and moss and debris, and we stood and it was so silent, then the eyewall started coming and we could hear a roar and rumble as a tornado went through town and cut all the trees off at the top, like a giant lawn mower. The only thing i hated was that the big roaches started flying when the gusts shook the house, an old wood frame florida house on piers. so i guess i came by my hurricane excitement honestly :)
the big flying raoches are scarier than the hurricane to me. lol!
Member Since: Posts: Comments:
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting CyclonicVoyage:


It is still just an invest with no LLC. Depending on organization today you'll most likely start hearing more about it tonight, most definitely tomorrow morning. Still a lot of fuzziness with this one, no need to call to order yet, IMO.


Agreed 100%
Member Since: Posts: Comments:
Quoting extreme236:


Well Well, there's the low we've all been waiting for.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Member Since: August 2, 2007 Posts: 19 Comments: 19234
275. unf97
Quoting TropicalAnalystwx13:


Cat 1, but we never know.


Too early to speculate about this. Just keep monitoring it closely.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting Floodman:


Tom, we're talking about landfalling hurricanes in SFL from the east before August...any strength
Hurricane 5 July 1933.
Member Since: Posts: Comments:
Of course, there's also this:

98L?

The setup here is beautiful.

NEXT!
Member Since: Posts: Comments:
Quoting DookiePBC:
Hmmm...been living in Palm Beach County since Feb 2006, so I haven't had to break out the shutters yet. Hope I don't have to now...who knows what's back in that corner of the garage...spiders? Iguanas? herds of wild Alpaca?

Amazing that the time frame for a POTENTIAL impact in South Florida is only a few days away and we haven't had nonstop local news coverage.


It is still just an invest with no LLC. Depending on organization today you'll most likely start hearing more about it tonight, most definitely tomorrow morning. Still a lot of fuzziness with this one, no need to call to order yet, IMO.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Quoting BahaHurican:
You know, there's really not enough going on with this system right now to justify calling it a "nasty storm". I myself am not seeing sufficient justification for even a highend cat one before it hits FL [not yet, anyway]. Let's not err on the side of the hyperbolic and possibly even ridiculous. Right now this is more of a "do you know where your shutters are" situation and less of a "batten up your houses now, quiet storm is coming down" one...

Peace [not pieces] everyone. Gotta run...


Thank you! I second all of the above! Let's all calm down so we can be sensible if plans have to be put in motion, instead of wearing out our psyches with premature hysteria.
Member Since: Posts: Comments:
Quoting hurricanejunky:


Wilma was in that ballpark when it passed by (not directly hit) Key West, submerging the island in some places with as much as 6 feet of water. I personally know the owner of Camille's had 4 feet of water in her house and lost 2 refrigerators, 2 freezers and 3 vehicles. Nothing to sneeze at. But I guess if you don't mind those conditions then yeah, you could stay.

That is a tough year for us in KW.
Member Since: Posts: Comments:
IKE.. what did you do this time??

Member Since: Posts: Comments:
Quoting Neapolitan:


You don't have to leave the Keys for anything less than a Cat 3: http://www.monroecounty-fl.gov/Pages/MonroeCoFL_Emergency/Evacuation
Right, that's where I got the info from, but was wondering if they changed policy for general evacs for CAT1. It was in the "talking" stage 2 years ago. Thanks.
Member Since: Posts: Comments:
Quoting kuppenskup:
Hey all-Im a South Florida resident right in the heart of Tamarac Florida. Does it look right now the worst this could be is a Tropical Storm when it gets to our doorstep?


Cat 1, but we never know.
Member Since: Posts: Comments:
Quoting Skyepony:


Midlevel. You can see it on radar but not surface obs.


Thanks Skye!
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting Neapolitan:


You don't have to leave the Keys for anything less than a Cat 3: http://www.monroecounty-fl.gov/Pages/MonroeCoFL_Emergency/Evacuation


Wilma was in that ballpark when it passed by (not directly hit) Key West, submerging the island in some places with as much as 6 feet of water. I personally know the owner of Camille's had 4 feet of water in her house and lost 2 refrigerators, 2 freezers and 3 vehicles. Nothing to sneeze at. But I guess if you don't mind those conditions then yeah, you could stay.
Member Since: Posts: Comments:
Quoting moonlightcowboy:
G'moring, StormW, all.


Seems the season "bust" yacking would wane with a developing system. LOL. It's still early - lots of season of left! Soon we could have more going on than we can shake a stick at - not looking forward to it either! Thanks to you folks who do the good, solid work - not just posting model and chart, one after another. Appreciate it. It's good to hear your thoughts, even be it maybe wrong sometimes - that's okay. If we wanted puters to tell us what we should do all the time, not sure I'd call that living or forecasting - that's just punching buttons, kind of like an ATM machine, looking for that instant result.


Thanks MoonlightCowboy!
Member Since: Posts: Comments:
Quoting TampaTom:


Cat 5 storms making landfall in the US

1935 - Labor Day storm (Mid keys)
1969 - Camille
1992 - Andrew


Tom, we're talking about landfalling hurricanes in SFL from the east before August...any strength
Member Since: Posts: Comments:
Quoting CybrTeddy:


Three recons too.
Darn, I'm not going to be able to be here tomorrow at all...that sucks.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting Floodman:


You're right; afternoon/evening of 7-31...so one in the record
I thought there might be one or two... most of the storms from this direction in July ended up closer to Fort Pierce, though, IIRC...
Member Since: Posts: Comments:
Glad to see the blog talking about weather again!

StormW,
What is the likely hood of us seeing a storm off our coast with 97l? In Pinellas/Pasco?
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Recon still slated to investigate 97L tomorrow...


Three recons too.
Member Since: Posts: Comments:
257. Skyepony (Mod)
Quoting hurricanejunky:
the circulation to the northeast of PR, is that low level or mid level?


Midlevel. You can see it on radar but not surface obs.
Member Since: Posts: Comments:
The TUTT in the western Gomex has some decent core convection this morning....

Link
Member Since: Posts: Comments:
Quoting FLdewey:


*dies of laughter*


Team members being able to communicate via intercom during intense storm conditions is imperative. It also helps to be able to speak to news desks with relatively low background noise which is what you get with an enclosed motorcycle helmet and noise canceling bluetooth interphones.
Member Since: Posts: Comments:
Thanks Storm!
Member Since: Posts: Comments:
253 posts in 90 minutes...It's gonna be a long day...
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting Michaelkaii10:
Hope Everyone in South Flordia has got a Hurricane Kit Ready Likes Beacuse this looks like a nasty Storm
You know, there's really not enough going on with this system right now to justify calling it a "nasty storm". I myself am not seeing sufficient justification for even a highend cat one before it hits FL [not yet, anyway]. Let's not err on the side of the hyperbolic and possibly even ridiculous. Right now this is more of a "do you know where your shutters are" situation and less of a "batten up your houses now, quiet storm is coming down" one...

Peace [not pieces] everyone. Gotta run...
Member Since: Posts: Comments:
Hey all-Im a South Florida resident right in the heart of Tamarac Florida. Does it look right now the worst this could be is a Tropical Storm when it gets to our doorstep?
Member Since: Posts: Comments:
Hey here's a wierd one (the obs are from 1866, so they aren't too reliable)...jumps out of the NE GOM as a CAT2:



Member Since: Posts: Comments:
Quoting StormW:


I believe they may have. We had a rep. from FLA. at the National Hurricane Conference who's office does the EVAC zones specifically for FL. She did say that some zones would be changed this season.


Except with certain conditions, you don't have to leave the Keys for anything less than a Cat 3: http://www.monroecounty-fl.gov/Pages/MonroeCoFL_Emergency/Evacuation
Member Since: Posts: Comments:
Recon still slated to investigate 97L tomorrow...
Member Since: September 2, 2009 Posts: 130 Comments: 21032
the circulation to the northeast of PR, is that low level or mid level?
Member Since: Posts: Comments:
Sorry if this has been posted already:

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1045 AM EDT TUE 20 JULY 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 21/1100Z TO 22/1100Z JULY 2010
TCPOD NUMBER.....10-050

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (NORTH OF HISPANIOLA)
FLIGHT ONE -- TEAL 70
A. 21/1800Z
B. AFXXX 01BBA INVEST
C. 21/1400Z
D. 21.0N 70.0W
E. 21/1700Z TO 21/2100Z
F. SFC TO 10,000 FT

FLIGHT TWO -- NOAA 49
A. 22/0000Z
B. NOAA9 02BBA SURV
C. 21/1730Z
D. NA
E. NA
F. 41,000 TO 45,000 FT

FLIGHT THREE -- TEAL 71
A. 22/0600Z, 1200Z
B. AFXXX 0303A CYCLONE
C. 22/0400Z
D. 22.0N 72.0W
E. 22/0500Z TO 22/1200Z
F. SFC TO 15,000 FT

2. SUCCEEDING DAY OUTLOOK: CONTINUE 6-HRLY FIXES IF
SYSTEM REMAINS A THREAT. A POSSIBLE G-IV
MISSION FOR 23/0000Z.
Member Since: Posts: Comments:
Quoting pvbeachbum:
Thanks for the analysis Dr. Masters - with my husband on a cargo ship doing a Caribbean run, this early information is very helpful for him and the ship to plan their route.


i hope they have a backup plan for the route other than this group haha
Member Since: Posts: Comments:
242. MahFL
On the radar it looks like the coc is slowly moving NW, about to cross east PR.
Member Since: Posts: Comments:
Quoting Jeff9641:
Once this pulls away from PR we should see this system really begin to build and this could happen later today or tonight. The SST around SE FL and the Bahamas are 88 to 90 which is like high octagne fuel so get ready we may be for some real trouble.
That gulf stream and Bahamas region is boiling. Dry air should probably be the only thing going against 97L when it reaches the Bahamas.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting hydrus:
I think hurricane 5 hit S.E.FL in 1933.


You're right; afternoon/evening of 7-31...so one in the record
Member Since: Posts: Comments:
Without mentioning names, we have team members in other states (outside of FL) that are trying to determine when to fly in for interception. Obviously it's early but with the way the models are clustering and conditions improving for development, we have to act quickly. Any forecast insight that would aid in solidifying our time line is very welcome. Thanks guys!
Member Since: Posts: Comments:
238. IKE
Quoting twhcracker:


this story kills me Ike! I remember when it happened. it just hurts my heart! I hope you got another dog!


I've got another one...had him since he was a pup.

I'll check back later today.


Member Since: Posts: Comments:

Viewing: 288 - 238

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 | 25 | 26 | 27Blog 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

Scattered Clouds
45 °F
Scattered Clouds