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

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

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

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Quoting PensacolaDoug:



[Joe Bastardi] is well respected among his peers.


A) Notice I did say "for my taste". B) But not among all his peers...or even a majority of them.

I won't go on and on about the guy; he's already been proven fairly proficient at meteorology, but utterly lacking at climatology. Again, though, it's just funny that he has ranted and raved--and continues to do so--about how this past winter's snowstorms (and the current southern hemisphere's cold snap) are absolute proof that AGW is a hoax and a fraud, yet he doesn't offer anything substantive about the all-time record heat in the northern hemisphere over the past four months. Not sure what his motivation is; it could be he simply doesn't want to admit that he's long been wrong abotu AGW. Then again, his frequent apperances on that bastion of journalistic excellence--Fox News--may indicate a more politically-driven agenda. Or so methinks...
If Dr. Masters was on NPR this morning, then he had to get up mighty early!
The NE side of 97L is supposed to be the strongest if and when it ever gets its act together. Lots of dry air to its west and shear on top of it.

Coordinates are about 20N 68.4W now which is the blob over Dominican Republic.
Very somber mood on the blog this morning compared to yesterday.
3004. P451
Quoting Jeff9641:


At it's position now a C FL event is more likely even with a WNW movement. Expect a Erin to Frances/Jeanne Track.


Just got to wait until it resumes an upper air steering current only heading.

Land is interfering with it. If you XTRAP it's present heading you're hitting the Pressolina's.

By this evening I think it'll settle into a track that the models (and we) can then pinpoint a probable landfall.
Poor bugger is dealing with that ULL which is not in a big hurry and Hispaniola is not exactly the best terrain to try and drop a coc. I see really slow development on this one, the only thing really going for it now is the hot water.
Quoting PensacolaDoug:
The model plots do suggest an ERIN path. That's 1995's ERIN.


Frances or Erin, same difference... both passed right over my house in west central Florida. Not fun.
3007. Tazbeat
Quoting Neapolitan:
JB is too self-aggrandizing and out-of-touch for my tastes. Does anyone really believe his nonsense that all-time record highs are proof of nothing, yet a deep but brief cold snap is proof that AGW is a farce? Yeah, okay...



Please keep in mind that the "all-time record highs" are based on a relatively miniscule amount of time when it comes to the history of the Earth. I don't think that anyone actually believes these are the warmest temps EVER, because we don't see ferns growing up in the Arctic quite yet. Perhaps the frenzy just needs to die down some, seeing as we're looking at such a tiny fraction of actual climactic history. Just because it's all we know, doesn't mean that's all there is.
Hi Quad. I respect your point of view. But your post makes it look like I'm the one saying it when I was just re-posting Joe Bastardi. Keeping the record straight here as always!
3010. P451
Quoting DoubleAction:
Poor bugger is dealing with that ULL which is not in a big hurry and Hispaniola is not exactly the best terrain to try and drop a coc. I see really slow development on this one, the only thing really going for it now is the hot water.


Pretty much the story at hand. Give it the day and then we'll all be a lot more confident on it's future.

Right now it's existence spreads wider than the official named storms forecast spread.

Anywhere from strong low pressure to hurricane is still in S-FL's forecast.

3011. srada
Good Morning Everyone!

So it looks like the models have trended for a more northern hit on florida? Central and Northern Florida now..this might not even make it in the GOM..heck it might not even hit florida if this trends keeps up..
Quoting beell:

Link


Looking at that I don't see much hope for 97.
Quoting HurricaneGeek:


Welcome!
Sorry but I don't have an answer for you.


Thanks 'Geek'... I have always had a great deal of respect for the hard work put into developing "reliable computer model databases". I hope the reliability continues to improve with advancements in data gathering technologies.
To put things in perspective, tomorrow 97L will be into the Bahamas and away from Hispanola, which should help aid in development. NHC still gives it a high chance and notes a TD is not expected to form today now anyway.
I'm starting to wonder if 97L is reorganizing SE of where the COC is supposed to be, seems to have split to me.
What's the ULL supposed to do in the next 24-48 hours?
3017. help4u
Tropics must be dead!All this global warming talk.Maybe something to talk about in tropics next week.
Quoting PensacolaDoug:
Hi Quad. I respect your point of view. But your post makes it look like I'm the one saying it when I was just re-posting Joe Bastardi. Keeping the record straight here as always!


Mornin Doug. Speak to Oz this AM?
Quoting PensacolaDoug:
Hi Quad. I respect your point of view. But your post makes it look like I'm the one saying it when I was just re-posting Joe Bastardi. Keeping the record straight here as always!


Eek! Sorry about that :) Shows if I'm going to comment on other people's posts that I should double check I've read them right :D Sorry to do that to you :)
Quoting stormpetrol:
I'm starting to wonder if 97L is reorganizing SE of where the COC is supposed to be, seems to have split to me.


Yesterday the CMC model was showing a storm spin up and travel to South Fl. and another right after it from about the same location about 48 hours hitting central fl. and traveling up the center of the state. Maybe this is what the model was alluding to?
3021. P451
Today's severe weather threats (animated image).




Link to severe wx products page.
Re: 3001


Ok then....
Not yet Junky. Prolly soon.
Quoting Quadrantid:


Eek! Sorry about that :) Shows if I'm going to comment on other people's posts that I should double check I've read them right :D Sorry to do that to you :)


No harm, no foul.
Quoting stormpetrol:
I'm starting to wonder if 97L is reorganizing SE of where the COC is supposed to be, seems to have split to me.


Crown Weather said that one scenario is that new low will for back to the SE where the strongest convection was left behind.
Quoting srada:
Good Morning Everyone!

So it looks like the models have trended for a more northern hit on florida? Central and Northern Florida now..this might not even make it in the GOM..heck it might not even hit florida if this trends keeps up..


what models are you looking at? everyone of the models I saw this morning shifted a little over toward MS/AL/Pensacola landfall in the gulf...
Mornin Storm!
Quoting earthlydragonfly:


Yesterday the CMC model was showing a storm spin up and travel to South Fl. and another right after it from about the same location about 48 hours hitting central fl. and traveling up the center of the state. Maybe this is what the model was alluding to?


It still is hinting at that senerio. Not as prominent as yesterday. It is now also showing a Storm in the Catl developing.
Good morning, StormW. :)
Morning Senior Chief Caster.... I got a new one today in reference to someone that acts like someone else here on the blog.

Copycat caster...
morn WU bloggers
Quoting earthlydragonfly:


Yesterday the CMC model was showing a storm spin up and travel to South Fl. and another right after it from about the same location about 48 hours hitting central fl. and traveling up the center of the state. Maybe this is what the model was alluding to?



When it comes to "cyclone-genesis" the CMC is a hardly a bastion of meteorlogical exelence!
Hi Guys here are the updated models from 8AM. Seems to be a split between C and a S FL landfall. I would go right down the center is my best guess and most do strengthing this to a strong TS or min Hurricane.


http://www.coaps.fsu.edu/~maue/tropical/models/AL97_2010072112.png
3036. gator23
Is Weather Underground South Casting? The model plots for the HWRF and GFDL are much further south here. Is Dr Masters a SouthCaster, someone please explain

Link

then here

Link
Quoting PensacolaDoug:
Quoting earthlydragonfly:


Yesterday the CMC model was showing a storm spin up and travel to South Fl. and another right after it from about the same location about 48 hours hitting central fl. and traveling up the center of the state. Maybe this is what the model was alluding to?



When it comes to "cyclone-genesis" the CMC is a hardly a bastion of meteorlogical exelence!


Oh I know.. Actually none of the model do a good job pre-cyclone genesis. But they can serve to hint at where to look for favorable environments in the future. They do very well with Current large weather pattern and what they may do in the future. So they can basically put a arrow on the map for us to check out.
what is difference between statistical and dynamic?
Copycat caster...


How bout "copycatster"?
3041. srada
Quoting louisianaweatherguy:


what models are you looking at? everyone of the models I saw this morning shifted a little over toward MS/AL/Pensacola landfall in the gulf...


ummm..I said if the northen trends keeps up..its kinda of hard for a storm to hit northern florida and geographically hit GOM for a second landfall unless it does a loop de loop..
Quoting PensacolaDoug:
Copycat caster...


How bout "copycatster"?


That could work too.. I like it.
WOW the Atlantic has close to 5 ULL's out there. I think it might be be a while before we see another hurricane.
3045. gator23
Quoting Jeff9641:
Hi Guys here are the updated models from 8AM. Seems to be a split between C and a S FL landfall. I would go right down the center is my best guess and most do strengthing this to a strong TS or min Hurricane.


http://www.coaps.fsu.edu/~maue/tropical/models/AL97_2010072112.png

Good morning Jeff, Yes I would say that the models have shifted north, however, our most accurate models th HWRF and especially the GFDL have not budged. They have been consistant in making this a Central/North Florida Storm. They have not changed much since this started and I have no reason to disagree. CUE THE MIAMI CASTERS
Quoting weatherwart:


Frances or Erin, same difference... both passed right over my house in west central Florida. Not fun.



rgr that.
Quoting KEEPEROFTHEGATE:


Thank Keeper, I posted the link as I don't know how to post images yet.
3048. srada
Quoting srada:


ummm..I said if the northen trends keeps up..its kinda of hard for a storm to hit northern florida and geographically hit GOM for a second landfall unless it does a loop de loop..


and I'm looking at the 12Z dynamic models
Storm W... when do you expect for that ULL to move away?
Something tells me by looking at the trend of models 97 might even go up the east coast like SC or NC.. is that all possible? Doesn't look like it will make it in the gulf..
Another caster for the books. For those that say see I told you I knew where it was going to hit.
"History Caster"
Linkcorrected
3056. gator23
Quoting gator23:
Is Weather Underground South Casting? The model plots for the HWRF and GFDL are much further south here. Is Dr Masters a SouthCaster, someone please explain

Link

then here

Link



This deserves a bump, anyone? anyone?
Ok storm are you going for the Redundant Caster title
3059. gator23
Quoting HurricaneNewbie:
Another caster for the books. For those that say see I told you I knew where it was going to hit.
"History Caster"


How about just plane old "forecaster"
Quoting gator23:



This deserves a bump, anyone? anyone?

Isn't he more of a WestCentralCaster? ;-)
Quoting StormW:


I'm checking stuff out now.

Gang, I would much appreciate if questions could be held until my update is posted so I may finish performing analysis.

TIA!


Ok everybody step back! Give the man some air!!
3062. gator23
Quoting weatherwart:

Isn't he more of a WestCentralCaster? ;-)

my favorite, MASTERCASTER
Linkcorrected
well i was thinking it was time for a Storm update but didnt want to be rude and ask :)
Quoting gator23:



This deserves a bump, anyone? anyone?

Ill split the difference and say GFS is prettty reasonable its right in the middle of all the models
DR MASTERS HAS A NEW BLOG UP!

I'll get mine update in the next hr or so:)
3069. srada
I hope Weather456 comes on this morning..very interested to hear his take on 97L
this morning on twc stephanie said la nina is forming and it means less hurricanes and that was a contributer to them changing their storm forecast for the season? Thats not fair for them to change the number in July. thats cheating.
Possible LLC forming near 20/70
What is the difference between the orange and yellow lines on the sheer maps?
Quoting DestinJeff:
2010 hurricane season is poised to go down in history as the most over-hyped event since Geraldo opened Al Capone's secret vault
we got a 132 days to go a lot can happen in 30 days that leaves 102 days for even more to happen
Quoting StormW:
COC Developing near 19.8N;69.7W based on visible satellite loop.

Woo hoo! I got one right! *happy dance*
Goodmorning all,

I have a feeling that once 97L gets away from the coast it will get its act together and will become stronger. Right now, I feel that everyone from the keys north to central florida should pay close attention to this system.
97L was split off all the convection to the east by the Cold dry air that comes off PR and DR at night as well as a mid level ridge of it's own making from all the convection yesterday that had poor outflow.

I is now nice and compact and over the Silver,Navidad banks.
This will allow it to to spin up very quickly and if it moves north away from the DR, Cuba and into the Bahamas it can become a TD/TS at anytime. So don't get complacent yet.

3078. cg2916
NEW BLOG!!!