Caribbean disturbance 93L to drench Honduras; 97L disturbance worth watching

By: Dr. Jeff Masters , 3:04 PM GMT on August 18, 2011

Share this Blog
21
+

A westward-moving tropical wave in the Central Caribbean a few hundred miles south-southwest of Jamaica, Invest 93L, has continued to increase in organization, and is close to tropical depression status. 93L is a small system, but has built up a respectable area of heavy thunderstorms around its center. A few low-level spiral bands are apparent on satellite imagery, but there is almost no upper-level outflow apparent, and a surface circulation is not obvious. 93L has moistened its environment somewhat over the past day, but dry air is still in evidence around the storm, particularly to the southeast, as seen on water vapor satellite images. Wind shear continues to be low, 5 - 10 knots. There is a hurricane hunter mission scheduled for this afternoon at 2pm EDT to see if a tropical depression is forming.


Figure 1. Morning satellite image of 93L.

Heavy rains from 93L will begin spreading over Northern Honduras and Northeast Nicaragua tonight. The forward motion of 93L will slow to 5 - 10 mph by Friday, so the storm could be a major rain event for Northern Honduras, with rain amounts of 4 - 8 inches likely by the time the storm reaches Belize on Saturday. Heavy rains will spread to Belize and Mexico's Yucatan Peninsula by Friday night or Saturday morning. The latest SHIPS model forecast shows wind shear remaining in the low range and the atmosphere steadily moistening over the next two days, which should allow 93L to reach tropical storm strength. All of the models agree that the ridge of high pressure steering 93L to the west will remain strong, forcing the storm into a landfall Friday in Northeast Honduras, or Saturday near the Belize/Mexico border. It is possible that 93L will have time to intensify into a Category 1 hurricane before then, though landfall as a tropical storm would be more likely, given the dry air that 93L needs to overcome, and the possibility that the storm will pass too close to the northern coast of Honduras. Regardless, heavy rain will be a major threat from 93L. NHC gave 93L an 80% chance of developing into a tropical depression by Saturday morning in their 8am outlook. If 93L does cross the Yucatan Peninsula and enters the Gulf of Mexico, a strong ridge of high pressure should keep the storm moving due west to make a second landfall along the Mexican coast, well south of Texas.


Figure 2. Morning satellite image of the tropical wave 97L midway between the Lesser Antilles and the coast of Africa.

Invest 97L midway between the Lesser Antilles and the coast of Africa
A tropical wave near 14°N 40°W, midway between the Lesser Antilles Islands and the coast of Africa, is moving westward near 15 - 20 mph. This wave, designated 97L by NHC this morning, has little heavy thunderstorm activity associated with it due to dry air, but an impressive amount of large-scale spin is obvious in visible satellite loops. 97L is expected to arrive in the Lesser Antilles Islands by Saturday. Over the past day, all four of our reliable models for predicting tropical storm genesis have predicted that this wave could develop into a tropical depression sometime Saturday through Monday, so 97L needs to be watched carefully. NHC gave 97L a 10% chance of developing into a tropical depression by Saturday morning in their 8am outlook, and it is unlikely that this storm will pose much of a threat to the Lesser Antilles. It will take several days for the storm to overcome the large amount of dry air surrounding it, even though wind shear is a low 5 - 10 knots. By Saturday, the wave will find a moister atmosphere and warmer sea surface temperatures near the northern Lesser Antilles, and more rapid development may occur. However, there is expected to be high wind shear associated with an upper level low pressure system to the north of Puerto Rico at that time, and this wind shear may interfere with development. 97L is expected to take a west-northwest track through the Northeast Caribbean bringing the storm near Puerto Rico by Sunday or Monday. Long-range model runs, which are highly unreliable, foresee that 97L could be a threat to Hispaniola, Eastern Cuba, the Bahamas, and Florida by the middle to end of next week.

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: 446 - 396

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 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74Blog Index

Quoting bayoubrotha:
17:05:30Z 14.933N 79.050W 569.7 mb
(~ 16.82 inHg) 4,825 meters
(~ 15,830 feet) 1007.5 mb
(~ 29.75 inHg
thats at 16,000 feet almost. 1009.9mb was ext surface pressure
Member Since: September 18, 2010 Posts: 0 Comments: 5248
445. xcool


12z cmc
Member Since: Posts: Comments:
Quoting WxLogic:
12Z NGP Develops 97L but is the eastern outlier for the time being (showing a weaker Bermuda High)


It is within the range shown by the 06Z GFS Ensembles
Member Since: Posts: Comments:
Quoting P451:
Odd flight plan....



are they aborting mission... they started climbing back up again
Member Since: Posts: Comments:
Thanks Levi for the video,things picking up as expected!
Member Since: Posts: Comments:
Quoting GTcooliebai:
well it shown the same in 3 straight runs, now I keep hearing that long range models aren't very accurate, but I must also assure some people that we've come a long way in technology and computers, and the upgrades & improvements made each year to our long range global models continue to improve. Obviously they're other factors that determine the outcome, like land interaction, but these models have an general idea of the dynamics that goes on in the atmosphere, like steering, positioning of ridges and trough, ull, dry air, and wind shear.


Some improvements recently, but nothing that takes things from 72 hours of usefulness to 200+ hours. If this track pans out in 10 days it will be a significantly rare event.
Member Since: Posts: Comments:
Quoting Levi32:
The recon plane is turning around and climbing in altitude. They must have had some technical difficulties.


LOL, They just called off the 2011 Hurricane Season. Done. Finished. Everyone can relax now...
Member Since: Posts: Comments:
Based on the orientation of the 500MB Heights I expect 93L to remain offshore and Belize becoming it's primary target.

Member Since: August 14, 2008 Posts: 4 Comments: 5038
Quoting synthvol:
Thanks Keeper and Angiest for the answers. And thanks to everyone for pointing out my "counting" error. Two quick turns in a row and fixing a fence in the Great Drought of 2011 has me a little dizzy (or nausious or ((insert your favority heat-related ailment here)). I hope whereever 97L/Irene(??) goes, the devastating effects are minimized.

Will be Harvey soon.
Member Since: Posts: Comments:
I wonder if the NHC will go ahead and classify 93L anyways.
Member Since: Posts: Comments:
Quoting benirica:
Don't get me wrong, I look at the models for guidance as much as the next guy... But looking at models a week out for a tropical wave that just became an invest and pinpointing a particular city is as farfetched as saying the gfs has a cat 10 over NOLA on Sept. 11, 2012. (yes 2012).
Once it actually develops you can give a model a week out more confidence... We know all too well how much they will change come Sunday.
I'm in PR and am not freaking out with it less than a week away... So come on guys, get a grip.


That's the typical Florida folks on this blog fer ya
Member Since: Posts: Comments:
Quoting Levi32:


As far as I know, JB wasn't available to be on this week?

I'm chatting to Bob in Storm chat right now. He is hopeful, He's accepted his Skype request. and they talked again today.
Member Since: Posts: Comments:
I think the HH want to start off at a SE entrance then head NW throught 93L
Member Since: Posts: Comments:
Thanks Keeper and Angiest for the answers. And thanks to everyone for pointing out my "counting" error. Two quick turns in a row and fixing a fence in the Great Drought of 2011 has me a little dizzy (or nausious or ((insert your favority heat-related ailment here)). I hope whereever 97L/Irene(??) goes, the devastating effects are minimized.
Member Since: Posts: Comments:
Thanks. I skimmed through, and there is indeed a vertical component to landscape considered by the GFS.
Member Since: Posts: Comments:
Quoting OviedoWatcher:
Lots of discussion here about why some models don't show degradation over mountainous regions of Cuba and Haiti. Does anyone know if the models actually consider terrain, or do they just have 'land' and 'water'? Anyone got a link to a site describing the assumptions the different models make?


Here is the link to the GFDL home page; please note that they have made additional upgrades to the model (their home page only lists the upgrades through 2006) but this gives you a nice overview of the process (including land interaction issues):

Link
Member Since: Posts: Comments:
how does 15.0N and 75.8W look for a COC on satellite?
Member Since: September 18, 2010 Posts: 0 Comments: 5248
12Z NGP Develops 97L but is the eastern outlier for the time being (showing a weaker Bermuda High)
Member Since: August 14, 2008 Posts: 4 Comments: 5038
Quoting TropicalWeatherGrl88:


That is what I am not understanding as well. If it hits that much land it will be much weaker more likely causing it to get into the eastern GOM. I think the GFS has been pretty consistan as far as track but the intensity has most to do with where the storm will go, and I do not think it is doing well on that.
If the centre is along the north side of the islands, I don't see as much impact from land interference. South of them is a bit different. Also someone mentioned that Sward bend at the end of models. I think that's pretty much been in there for a while. Several of the runs I've seen have brought the storm west and south under / along the southern tip of FL and around that way. Somebody got @#*&%$ out for mentioning Katrina, but certainly some runs have been making that little dip over FL. Ike is another example, as was Fay. Don't forget - 2008 is an analogue year, so I'm not surprised to see some runs similar to storms we saw that year.
Member Since: Posts: Comments:
The recon plane is turning around and climbing in altitude. They must have had some technical difficulties.
Member Since: Posts: Comments:
The HH are climbing back to 25000 feet something must have gone wrong .
Member Since: January 10, 2010 Posts: 0 Comments: 938
Recon heading back home? they just made a U-Turn
Member Since: Posts: Comments:
Quoting FLdewey:


Unless the storm goes to NC of course.

Yeah, it was pretty hard to see the ";-)" in my post.

I'll bold it next time. ;-)


LOL, Everyone thinks it might be coming for them until it completely disipates!
Member Since: Posts: Comments:
17:05:30Z 14.933N 79.050W 569.7 mb
(~ 16.82 inHg) 4,825 meters
(~ 15,830 feet) 1007.5 mb
(~ 29.75 inHg
Member Since: Posts: Comments:
Quoting StormHype:


Let me know if it shows the same in 7 days from now.
well it shown the same in 3 straight runs, now I keep hearing that long range models aren't very accurate, but I must also assure some people that we've come a long way in technology and computers, and the upgrades & improvements made each year to our long range global models continue to improve. Obviously they're other factors that determine the outcome, like land interaction, but these models have an general idea of the dynamics that goes on in the atmosphere, like steering, positioning of ridges and trough, ull, dry air, and wind shear.
Member Since: Posts: Comments:
Time: 16:45:00Z
Coordinates: 15.0N 78.5W
Acft. Static Air Press: 587.8 mb (~ 17.36 inHg)
Acft. Geopotential Hgt: 4,569 meters (~ 14,990 feet)
Extrap. Sfc. Press: 1009.9 mb (~ 29.82 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 141° at 9 knots (From the SE at ~ 10.3 mph)
Air Temp: 0.6°C (~ 33.1°F)
Dew Pt: -14.3°C (~ 6.3°F)
Peak (10s) Flt. Lvl. Wind: 10 knots (~ 11.5 mph)
SFMR Peak (10s) Sfc. Wind: -
SFMR Rain Rate: -

lowest pressure yet 1009.9mb
Member Since: September 18, 2010 Posts: 0 Comments: 5248
Quoting AussieStorm:

Levi, I hear your going to be on a certain show tonight along with another 2 people. Joe B and a former WU Blogger.


As far as I know, JB wasn't available to be on this week?
Member Since: Posts: Comments:
Quoting USAFwxguy:
Fresca is a great beverage, but I'd never drink it out of an old milk jug. No way.
for a thousand dollars..?
Member Since: Posts: Comments:
HH heading back the way they came BY BY
Member Since: January 10, 2010 Posts: 0 Comments: 938
93L looking good... hats off to Tampaspin for calling the development not until the western Caribbean the other day. Good call!

97L looking lethargic, although has a nice spin. Will watch and wait to see what happens. Still looks like it has to fight off a bit of dry air. Current models not the best news for the CONUS, but still a long way out for sure... but the agreement is outstanding between them, so it seems... and consistent.
Member Since: Posts: Comments:
407. srada
Quoting FLdewey:


Unless the storm goes to NC of course.

Yeah, it was pretty hard to see the ";-)" in my post.

I'll bold it next time. ;-)


We cant help that NC is feeling the love from the models!
Member Since: Posts: Comments:
What is recon. doing?
Member Since: Posts: Comments:
Quoting CybrTeddy:


Where did I say that 'yes, its going to make landfall in Tampa!!!' I was stating what the GFS was showing. Last run it had it in a totally different place in Florida.
Look, you and I both know that 97L will move over and stall right on top of Northern South America, where it will take in large amounts of fine Colombian weed..
Member Since: Posts: Comments:
Quoting USAFwxguy:
Beginning to see what everybody was saying...about the craziness that ensues around here.

Very interesting. Funny, too.


Wait till people start posting made-up models. I think we still have one that says Emily will eventually reform and hit the Carolinas as a major. Those McTavish numbers were just so high.

To any newbies reading, what I just said is not going to happen, it came from someone else's sick idea of a joke.
Member Since: Posts: Comments:
Don't get me wrong, I look at the models for guidance as much as the next guy... But looking at models a week out for a tropical wave that just became an invest and pinpointing a particular city is as farfetched as saying the gfs has a cat 10 over NOLA on Sept. 11, 2012. (yes 2012).
Once it actually develops you can give a model a week out more confidence... We know all too well how much they will change come Sunday.
I'm in PR and am not freaking out with it less than a week away... So come on guys, get a grip.
Member Since: Posts: Comments:
Quoting Levi32:
Good morning.

Blog update:

Tropical Tidbit for Thursday, August 18th, with Video

Levi, I hear your going to be on a certain show tonight along with another 2 people. Joe B and a former WU Blogger.
Member Since: Posts: Comments:
399. GoWVU
Quoting ncstorm:
right now models are not long range to the people in the islands..


ncstorm, so so true!!
Member Since: Posts: Comments:
Quoting angiest:


My understanding is the Greek letter is "retired" to reference the storm, but is actually still used if needed.
iam not really sure myself and hope not to find out by seeing a storm that far up the list iam thinking no more than 21 this season
Member Since: Posts: Comments:


Member Since: Posts: Comments:

Viewing: 446 - 396

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 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74Blog 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

Overcast
31 °F
Overcast

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron