97L continues to grow more organized; headed for Bahamas and Florida

By: Dr. Jeff Masters , 7:07 PM GMT on July 20, 2010

Share this Blog
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

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: 1928 - 1878

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 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62Blog Index

Quoting CosmicEvents:
What's the point of bringing up cyclones from times past that are now dead if you only look at landfall point and disregard the track?
.
.
I need a break from this place. sigh


similar synoptic steering patterns were in place back then
and those particular storms also made landfall in central
Florida.

Why is that hard to comprehend? it was just a
steering pattern setup that reminds many of this
current scenario.

Studying past storms and past track histories for comparison
is what all good stormchaser and Mets do.

Even Dr. Masters will mention past storm tracks sometimes.

Member Since: Posts: Comments:
1927. bappit
The dry air took out the leading convection yesterday while convection increased on the trailing side under the little anticyclone that was ketchin' up.

Today that small anticyclone stands transformed into a mighty shield of anticyclonicity pressing against the forces of the evil King TUTT and his dry air minions.
Member Since: Posts: Comments:
Quoting Orcasystems:

DIIK?
I would assume they are tired of pointing at Texas... wait 48 hours.

lol
Member Since: Posts: Comments:
Quoting Grothar:


I see someone is in a good mood. How you doing T? We were very technical a while back, but nothing new yet. Waiting till the 11 PM advisory, unless it is already out.


Hey Bro....looking at the most recent loops look rather YIKES !!!!
Member Since: Posts: Comments:
Quoting AlexEmmett:
orca, wth do the models have against florida and the gulf

DIIK?
I would assume they are tired of pointing at Texas... wait 48 hours.
Member Since: Posts: Comments:
convection over Haiti shows signs of weakening, likely do to the loss of instability in the atmosphere, and fueled by wind shear right now. This should weaken as the night wears on. This was not caused by 97L directly.
Member Since: Posts: Comments:
I think there is a decent chance this goes straight to tropical storm Bonnie, it could be a minimum hurricane before reaching Florida and who knows where she moves after that.
Member Since: Posts: Comments:
Quoting Skyepony:
Model error after 24hrs in nm..

AEMN 84.3
OFCL 93.9
BAMD 115.4
LGEM 150.4
BAMM 160.8
XTRP 179.7
LBAR 188.1
HWRF 238.5
BAMS 297.6
That's a great point to keep in mind for ALL the storms that we have in a season(or a few seasons)....but isn't each cyclone unique? You know much more than I, and most everyone. Is there something that you see in the synoptic set-up with this particular cyclone that leads you to think we'll see a 150NM error in this case? In 24 hours....or even in 96 hours. I'd be really interested to hear some informed case being made for a move south of Cuba or North of Daytona.
Member Since: Posts: Comments:
1918. gator23
Quoting zoomiami:
someone said the other night that hurricanes in So Florida are over rated, they don't happen that often.

I've been through so many hurricanes, I don't even know their names. Just because only one of them was a cat 5 that destroyed an entire area does not make it a calm place to be.

I've been here since 1983


1)They happen more often down there
2) They are "felt" for a longer period of time because they generally dont weaken as much when crossing South Florida as is the case everywhere else, in other words the second half of the storm can be as storng as the first half.

So whoever said that doesnt know what they are talking about.
Member Since: Posts: Comments:
orca, wth do the models have against florida and the gulf
Member Since: Posts: Comments:
Quoting gator23:
FTW



^^^Me before gear.

<--- Me after gear.
Member Since: Posts: Comments:
1915. bappit
Quoting Chicklit:
I've got perspective cuz I have hardly been here, and can tell you, 97L has scarcely moved since last night.

It's, ummm, back building. The discussion says the waved moved on to Cuba leaving a surface trough with strong convergence. Surface convergence extends south from the Virgin Islands on the CIMSS map.
Member Since: Posts: Comments:


Very tight consesus of direction for this far out!
Member Since: Posts: Comments:
Pick a track.. any track :)



AOI
Member Since: Posts: Comments:
1912. Patrap
41 Years ago @ 10:56 Pm EST

20 July 1969



Member Since: Posts: Comments:
Quoting ackee:
Any one think NHC Will call this a TD AT 2am OR THEY WAIT On recon first

i give it a 40% chance 90% chance tommarow
Member Since: Posts: Comments:
1910. Grothar
Quoting TampaSpin:
Looks like the blog is completely filled with negative comments and non-sense as usuall when things get active....nothing knew!


I see someone is in a good mood. How you doing T? We were very technical a while back, but nothing new yet. Waiting till the 11 PM advisory, unless it is already out.
Member Since: Posts: Comments:
Just want it the heck out of Haiti.
They've got troubles enough.
Goodnight.
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
I still wonder if 97L will be like Erin in 1995--track and time of year are similar.

Although I do doubt 97L will be a hurricane before hitting FL. But ya never know for sure...


How 'bout the election?

97L might be a TD soon I think.
Member Since: Posts: Comments:
1907. xcool
td come.imo
Member Since: September 26, 2009 Posts: 2 Comments: 15603
last 4 hours PR radar showing massive rains offshore
Member Since: September 4, 2007 Posts: 0 Comments: 232
Good Blog entry. I was always curious, Is CCHS Cooper City High School?
Member Since: Posts: Comments:
Quoting scott39:
LOL, " " doesnt always keep us safe from blasting.j/k


i know. i'm scared to say anything too definitive on here. some people are ruthless, so i use a lot of question marks and " "

it makes me feel "safe" - there i go again :)
Member Since: Posts: Comments:
Quoting TampaSpin:


Hello....sorry started watching some of the BAseball game...dang! Got a storm we gotta watch for sure.



yes definitely!
Member Since: Posts: Comments:
Quoting Skyepony:
ASCAT was a total miss.

CaneWarning~ if you clicked on the image it would take you to the site.

& for the one not buying it..it's the Offical forecast..just passing it along..


Thank you.
Member Since: Posts: Comments:
The about to become TD is getting her act together now.....NO DOUBT!
Member Since: Posts: Comments:
1899. ackee
Any one think NHC Will call this a TD AT 2am OR THEY WAIT On recon first
Member Since: July 15, 2008 Posts: 0 Comments: 1341
1898. Skyepony (Mod)
Quoting xcool:
oh yeah 97L LOOK GOOD NOW


It does.. I could see it being a TD by morning.
Member Since: Posts: Comments:
Quoting TampaSpin:
Looks like the blog is completely filled with negative comments and non-sense as usuall when things get active....nothing knew!
that would be "new" ...just busting your chops :)
Member Since: Posts: Comments:
1896. Grothar
Quoting zoomiami:
someone said the other night that hurricanes in So Florida are over rated, they don't happen that often.

I've been through so many hurricanes, I don't even know their names. Just because only one of them was a cat 5 that destroyed an entire area does not make it a calm place to be.

I've been here since 1983


My mother's family moved to Miami in 1923!
Although I spent a lot of time in Europe, the first Hurricane I remember was 1948 and a lot since. We used to get hit in South Florida all the time and then in the mid-60's is stopped until David and then Andrew in 1992. Looks like we are back in the old pattern again.

P.S. I am very old, just ask anyone on the blog. lOL
Member Since: Posts: Comments:
For the first time in nearly two years, I have posted a new blog entry here on Wunderground with my analysis and forecast for Invest 97L.
Member Since: Posts: Comments:
00z shear analysis shows wind shear decreasing over the newer expected surface low developing within the newest area of deep convection within the center of the large convective cloud envelope. Outflow is improving and the ULL seems to be having less of an effect as it is showing signs of weakening. 200mb vorticity charts show that the ULL is no longer circular and rather more of a weaker trough. While looking at the water vapor imagery, the large cloud mass of 97L is showing a lot of anticyclonic flow, signs of an anticyclonic circulation over the system or an upper level anticyclone developing over the system. Wind shear should continue to decrease if indeed what I see right now is happening. What I believe is currently happening is that we are getting a reformation of LLC due to the fact that it remains somewhat disorganized. The two center jumps today were do to the overall circulation of the system. MLC was located near the north coast of Puerto Rico, but do to the presence of strong or moderate wind shear, the MLC was unable to organize a LLC last night. Today, we had another LLC develop while the MLC weakened and dissipated. Now that LLC has dissipated or reformed to the east near the more centralized area of deep convection. This convection is colocated with the best surface convergence and upper level divergence which are signs of possible development of the system. TD seems likely by tomorrow afternoon when the HH visit the system. Dry air does not seem to be much of a problem due to the weakening presence of the upper level low located to the WNW of 97L. Upper level outflow is becoming established throughout the system and wind shear should continue to decrease within the system's circulation. The area of centralized circulation appears to be now within the overall structure of the system. As in, now the convection is consolidating into one area. The convection on the eastern side of the system is no longer persisting and appears to be weakening as the newest convection continues to fire over the center or low pressure. While the system still remains pretty disorganized at the surface, conditions are becoming more and more favorable for development into a tropical cyclone. Steering currents remain towards the WNW. Land interaction from tomorrow towards landfall with FL will be the main detriment to the system's overall organization progress. This is of course with the latest development with the Upper level low pressure center I have previously mentioned. Wind shear caused by the large upper level anticyclone winds and the upper level low to the WNW of 97L is causing the convective flareup over Haiti currently seen on satellite imagery. This has no effect on 97L and therefore I do not see this as sucking energy away from any convection production in the future for 97L. Pretty massive upper level anticyclonic flow can be seen from an axis around 25N/65W to 5N/65W. The center of this axis appears to be around 18N/67W, or right near the recent blowup of convection, or nearest the newest probable LLC. A lot going for 97L tonight, lets see what happens by tomorrow afternoon when the HH fly into the system. Guess is they will find TS Bonnie.
Member Since: Posts: Comments:
Miami Discussion:

ATTENTINON THEN TURNS TO THE VIGOROUS TROPICAL WAVE NEAR PUERTO
RICO. NHC IS MONITORING THIS WAVE NEAR FOR POSSIBLE TROPICAL
CYCLONE DEVELOPMENT. IN FACT...THEY INCREASED THE PROBABILITY OF
DEVELOPMENT NEXT 48 HR TO 60%. THIS WAVE NEEDS TO BE CLOSELY
WATCHED AS MOVEMENT WILL CONTINUE ON A GENERAL WEST NORTHWEST
TRACK TOWARDS THE LOCAL AREA. REGARDLESS OF DEVELOPMENT...THERE
IS THE POTENTIAL FOR HEAVY RAIN/GUSTY WINDS ACROSS SOUTH FL IN THE
FRI-SAT TIME FRAME...WITH FOCUS LOOKING LIKE FRIDAY. HAVE
INCLUDED THIS IN THE HAZARDOUS WEATHER OUTLOOK. FORECAST DETAILS
WILL BE MORE PINNED DOWN IN THE COMING DAYS (OF COURSE!)...AND ALL
IS DEPENDENT ON WHETHER OR NOT THIS WAVE DEVELOPS. POPS WERE
INCREASED THU NIGHT-SAT ALONG WITH SKY COVER. THE FORECAST FOR
LATE IN THE WEEK IS HIGHLY UNCERTAIN. STAY TUNED. /GREGORIA
Member Since: Posts: Comments:
Nice chattin' w/yall. Usually just lurk. Gonna turn in. Got a busy day unrelated to Bonnie. But also my shop is @ 2' AMSL on Sugarloaf bayside. Better to elevate some things just in case as we have time. I follow the $100.00 rule. If it's worth a $100.00 or more , put it up 4'. Wilma cost me 125K out of pocket. Georges was a little cheaper.
Member Since: Posts: Comments:
1890. Skyepony (Mod)
ASCAT was a total miss.

CaneWarning~ if you clicked on the image it would take you to the site.

& for the one not buying it..it's the Offical forecast..just passing it along..
Member Since: Posts: Comments:
Looks like the blog is completely filled with negative comments and non-sense as usuall when things get active....nothing knew!
Member Since: Posts: Comments:
Bonnie-to-be has lots of junk in her trunk.

ROTFL, but so very accurate.
Member Since: Posts: Comments:


got some surface wind sea's are pretty choppy
around 97L
Member Since: Posts: Comments:
1886. gator23
Quoting GainesvilleGator:
I am not wishcasting but wouldn't mind having a day off of work from soon to be Bonnie. Just one day, thats it.

Ill meet you at Westside park, we'll throw the Frisbee around.
Member Since: Posts: Comments:
Quoting txsweetpea:



Hey Tampa!


Hello....sorry started watching some of the BAseball game...dang! Got a storm we gotta watch for sure.
Member Since: Posts: Comments:
www.esl.lsu.edu/webpics/AOI/AOI1_ir_loop.gif
Member Since: Posts: Comments:
1883. centex
Still waiting for land interaction to be mentioned besides me and JM hours ago. NHC did not bother to mention as factor in TWO, not a knock they just tell us what they expect not the entire why's. Wish they would let us pick their brain.
Member Since: Posts: Comments:
1882. OneDrop
Quoting KoritheMan:
Just did a blog on 97L.

For all you people that are high on caffeine, check out this blog and then go get some sleep, this is all you need to know until tomorrow.
Member Since: Posts: Comments:
Looks like a center trying to form about 30 miles north of the northern coast of PR.

Link
Member Since: Posts: Comments:
1880. xcool
oh yeah 97L LOOK GOOD NOW
Member Since: September 26, 2009 Posts: 2 Comments: 15603
1879. scott39
Quoting truecajun:


gettin' that TD "look"
LOL, " " doesnt always keep us safe from blasting.j/k
Member Since: June 13, 2009 Posts: 0 Comments: 6706
Quoting ChillinInTheKeys:
A lot of people did evacuate the Keys for Andrew. Most of them went to MIA or FTL.


Unfortunately a bunch went to homestead. I know several people who brought their boats up out of the keys, only to have them destroyed in Homestead.
Member Since: Posts: Comments:

Viewing: 1928 - 1878

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 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62Blog 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.