Dr. Jeff Masters' WunderBlog

97L continues to grow more organized; headed for Bahamas and Florida
Posted by: Dr. Jeff Masters, 7:07 PM GMT on July 20, 2010 +1
A tropical wave (Invest 97L) between Puerto Rico and the Dominican Republic has continued to become more organized today, and is a threat to develop into a tropical depression as early as Wednesday morning. The disturbance has brought heavy rains of 8+ inches to Culebra and Vieques islands over the past day, 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 - 15 knots, which should allow 97L to continue to develop today. Satellite images of 97L show a moderate area of steadily organizing thunderstorms, with curved bands developing to the north and east of the center. There are no signs of a surface circulation on satellite imagery or on the 10:38am EDT ASCAT pass. Surface observations show only light winds over Puerto Rico and the Dominican Republic, but the surface winds at Punta Cana on the eastern tip of the Dominican Republic have shifted to the west this afternoon, indicating that a surface circulation may be forming just north of that location. Long-range radar loops from San Juan do not show any evidence of a surface circulation. The Hurricane Hunter mission scheduled for today was canceled, but is scheduled to fly Wednesday afternoon.


Figure 1. Total precipitation from 97L as predicted by the 12Z (8 am EDT) July 20, 2010 run of the HWRF model. Image credit: Morris Bender, NOAA/GFDL.

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 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. The latest suite of model runs from 8am EDT this morning (12Z) foresee a more northerly track for 97L into Central Florida. Several models develop 97L into a tropical storm, with both the GFDL and HWRF models predicting 97L will hit South or Central Florida as a tropical storm on Friday. Most of the models have 97L entering the Gulf of Mexico on Saturday, but the amount of time 97L has over the Gulf may be limited to a day or less if the storm ends up exiting into the Gulf near Tampa Bay. The NOGAPS model predicts a more southerly path across South Florida and into Louisiana.

Intensity Forecast for 97L
One factor potentially aiding development of 97L 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 stay in the moderate range, 10 - 20 knots, over the next five days. The primary detriment to development of 97L over the next three days will probably 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. If the center forms close to the coast of the Dominican Republic, the high mountains of Hispaniola may also be a problem for the storm. NHC is giving 97L a 60% chance of developing into a tropical depression by Thursday, 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 today or on Wednesday is unlikely, due to the dry air over the Bahamas. I put the odds of 97L making it to hurricane strength before reaching Florida at 30%, 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 land or interacting with land over the next four days, which is very uncertain.

"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
Categories: Hurricane
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3. Kendrix 7:09 PM GMT on July 20, 2010    
Thanks For the Update Dr.
Member Since: June 11, 2008 Posts: 0 Comments: 14
5. AlexEmmett 7:11 PM GMT on July 20, 2010    
hwrf
6. Drakoen 7:11 PM GMT on July 20, 2010    
Thanks for the update
Member Since: October 28, 2006 Posts: 57 Comments: 29010
8. 69Viking 7:13 PM GMT on July 20, 2010    
Quoting smmcdavid:


I'm pretty sure that there is always some uncertainty in the track. :)


Yep and that's why I'm not to worried about it just yet, too many models pointing right at me this far out has to change LOL!
Member Since: August 25, 2006 Posts: 0 Comments: 2247
9. muddertracker 7:13 PM GMT on July 20, 2010    
Thanks, Doc!
Member Since: August 16, 2007 Posts: 1 Comments: 2118
12. MiamiHurricanes09 7:14 PM GMT on July 20, 2010    
Thanks for the update.
Member Since: September 2, 2009 Posts: 129 Comments: 19976
14. smmcdavid 7:14 PM GMT on July 20, 2010    
Quoting 69Viking:


Yep and that's why I'm not to worried about it just yet, too many models pointing right at me this far out has to change LOL!


True story.
Member Since: September 20, 2005 Posts: 31 Comments: 2309
17. xcool 7:14 PM GMT on July 20, 2010    
ooh boy
Member Since: September 26, 2009 Posts: 2 Comments: 15501
18. GoodOleBudSir 7:14 PM GMT on July 20, 2010    
Quoting sporteguy03:


nice one see I knew you were around ducking the blog.


It aint him
Member Since: July 30, 2008 Posts: 0 Comments: 261
19. Tazmanian 7:15 PM GMT on July 20, 2010    
00
NOUS42 KNHC 201445
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.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
JWP


so when did 97L go red?
Member Since: May 21, 2006 Posts: 5088 Comments: 111335
21. CaribbeanIslandStorm 7:16 PM GMT on July 20, 2010    
Thanks for the update !!!
22. muddertracker 7:17 PM GMT on July 20, 2010    
Quoting StormW:
I got a feeling.
That tonight's gonna be a good, good night?
Member Since: August 16, 2007 Posts: 1 Comments: 2118
23. hydrus 7:17 PM GMT on July 20, 2010    
Quoting Drakoen:
Thanks for the update
Link The GEM model has another low following 97L into the Florida Straits.
Member Since: September 27, 2007 Posts: 1 Comments: 14252
24. Drakoen 7:17 PM GMT on July 20, 2010    
Member Since: October 28, 2006 Posts: 57 Comments: 29010
25. weathermanwannabe 7:17 PM GMT on July 20, 2010    
Thank You Dr............Here's hoping, rain and flooding issues aside, that it stays on the low end of the scale (TD/TS) whether approaching the FL peninsula or after emerging into the Gulf after interaction with land.
Member Since: August 8, 2006 Posts: 0 Comments: 6687
26. ecflweatherfan 7:17 PM GMT on July 20, 2010    
Just checking in today... and all I got to say is WOW! High chance of development for 97L... and expected to head towards South or Central Florida. We sure need the rain here along the coast of East-Central Florida, just not the other crap that comes with it.
Member Since: March 19, 2010 Posts: 0 Comments: 947
28. ElConando 7:17 PM GMT on July 20, 2010    
Thanks for the post Dr. M
Member Since: September 6, 2009 Posts: 2 Comments: 3703
29. hydrus 7:17 PM GMT on July 20, 2010    
Quoting StormW:
I got a feeling.
Please explain your (feeling).
Member Since: September 27, 2007 Posts: 1 Comments: 14252
30. help4u 7:18 PM GMT on July 20, 2010    
Storm W are you hooked on a feeling or you just got a feeling?LOL
Member Since: September 18, 2006 Posts: 0 Comments: 1069
31. MiamiHurricanes09 7:18 PM GMT on July 20, 2010    
Quoting StormW:
I got a feeling.
An urge to do "#2" feeling? The Black Eyed Peas song? Or is it related to 97L?
Member Since: September 2, 2009 Posts: 129 Comments: 19976
32. Seflhurricane 7:19 PM GMT on July 20, 2010    
Quoting StormW:
I got a feeling.
storm i got a bad feeling about this!!! i think we may have a strong TS affecting SE florida
Member Since: July 14, 2009 Posts: 0 Comments: 2898
35. Tropicaddict 7:19 PM GMT on July 20, 2010    
Quoting StormW:
I got a feeling.



of???????????????
Member Since: September 25, 2007 Posts: 0 Comments: 207
36. sporteguy03 7:20 PM GMT on July 20, 2010    
Quoting StormW:


Click on #15 and go to his blog...what do you see?

yep I saw that too.
Member Since: July 7, 2005 Posts: 0 Comments: 4824
37. MiamiHurricanes09 7:20 PM GMT on July 20, 2010    
97L organizing nicely; likely to could become a tropical depression in less than 24 hours.

Member Since: September 2, 2009 Posts: 129 Comments: 19976
38. cchsweatherman 7:20 PM GMT on July 20, 2010    
Thanks for the update Dr. Masters. Right now, the low level circulation is becoming more evident on visible satellite imagery as banding has begun to develop over the Hispanola coastline moving westward towards the circulation center. In addition, the low level structure has become better defined with this developing banding. Still needs to establish better outflow to the west, but it continues to gradually become better organized. In this forecaster's opinion, I would expect a tropical depression or even Tropical Storm Bonnie in the next 12 hours or so.

Regarding the future track, this may be the easiest system to forecast a track for in quite some time. Computer models show essentially no change in steering for the next five days which means that the Bahamas and South Florida will be affected by whatever develops from Invest 97L, whether a depression or hurricane. Those in the Bahamas and South/Central Florida should keep a close eye on this system over the next few days.
Member Since: April 14, 2007 Posts: 8 Comments: 4926
39. Tazmanian 7:21 PM GMT on July 20, 2010    
lol evere one from FL is going too be in this blog


this blog is going too go nuts
Member Since: May 21, 2006 Posts: 5088 Comments: 111335
40. KEEPEROFTHEGATE (Mod) 7:21 PM GMT on July 20, 2010    
NMFC Norfolk Tropical Feed
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (NMFC CDO) from Naval Maritime Forecast Center Norfolk Virginia. Published on .

As of Tue 20 Jul 2010 19:00:02Z

2010 Storms
All Active Year


Atlantic
97L.INVEST(POSS.T.C.F.A.)
East Pacific
NONE
Central Pacific
NONE
West Pacific
97W.INVEST(T.C.F.A.Cancelled)
04W.CHANTHU
Indian Ocean
NONE
Southern Hemisphere
NONE
Member Since: July 15, 2006 Posts: 143 Comments: 40465
42. MiamiHurricanes09 7:21 PM GMT on July 20, 2010    
Quoting StormW:


Click on #15 and go to his blog...what do you see?
Nothing. It's just another Weather456 wannabe.
Member Since: September 2, 2009 Posts: 129 Comments: 19976
44. unf97 7:21 PM GMT on July 20, 2010    
Thanks Dr. Masters for your quick update on 97L.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
45. WeatherNerdPR 7:22 PM GMT on July 20, 2010    
Thanks for the update.
Member Since: July 7, 2010 Posts: 0 Comments: 5464
46. CyclonicVoyage 7:22 PM GMT on July 20, 2010    
Thanks for the update Dr. Masters.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
47. 900MB 7:22 PM GMT on July 20, 2010    
Storm-
The Doc has this going more north and you have it more south. What's the deal?
Thx!
Member Since: June 11, 2006 Posts: 0 Comments: 609
48. ElConando 7:22 PM GMT on July 20, 2010    
Quoting MiamiHurricanes09:
Nothing. It's just another Weather456 wannabe.


Yep, his typing style is completely different.
Member Since: September 6, 2009 Posts: 2 Comments: 3703
49. mtyweatherfan90 7:22 PM GMT on July 20, 2010    
Thanks for the update Dr.Masters!

hi everyone! :D
Member Since: July 9, 2008 Posts: 8 Comments: 334
50. KEEPEROFTHEGATE (Mod) 7:23 PM GMT on July 20, 2010    
NMFC Norfolk Tropical Feed
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (NMFC CDO) from Naval Maritime Forecast Center Norfolk Virginia. Published on .

As of Tue 20 Jul 2010 19:00:02Z

2010 Storms
All Active Year


Atlantic
97L.INVEST(POSS.T.C.F.A.)
East Pacific
NONE
Central Pacific
NONE
West Pacific
97W.INVEST(T.C.F.A.Cancelled)
04W.CHANTHU
Indian Ocean
NONE
Southern Hemisphere
NONE
Member Since: July 15, 2006 Posts: 143 Comments: 40465
51. Hardcoreweather2010 7:23 PM GMT on July 20, 2010    
Member Since: January 24, 2010 Posts: 0 Comments: 529

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About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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