Three tropical systems to watch

By: Dr. Jeff Masters , 4:27 PM GMT on June 24, 2006

Share this Blog
0
+

The tropics are getting more interesting today, with three systems to discuss. None of these systems poses a significant threat to any land areas, with the possible exception of Bermuda, for the last system I'll discuss.

Firstly, the low pressure system northeast of the Bahama Islands remains very disorganized today. The dry air to its west has been inhibiting its growth, despite the presence of relatively modest wind shear of 5 - 10 knots overhead. The wind shear is coming from the west, which is driving the dry air over Florida into the heart of the storm's circulation. If the wind shear had been from the opposite direction, where there is less dry air, the storm would have had a better chance of coming together. The system appears as a blob of clouds with just a few areas of deep thunderstorms, rotating about a broad and ill-defined center.


Figure 1. Preliminary model tracks for the Bahamas blob.

The Hurricane Hunter aircraft scheduled to investigate the system today has been cancelled, but is scheduled to fly on Sunday if needed. The system still has the potential to organize into a tropical depression, but its window of opportunity it getting short. The system should make landfall by Sunday or Monday along the northern Florida, Georgia, or South Carolina coast and dissipate inland. The dry air will continue to be a problem for the storm today, but may get diluted enough Sunday to allow some organization to occur.


Figure 2. Visible satellite image of the three tropical disurbances to watch today.

Low 800 miles east of Bermuda
A second area to watch is a well-defined area of low pressure far out in the Atlantic at 34N 51W, about 800 miles east of Bermuda. There is deep thunderstorm activty completely surrounding the low, and QuikScat satellite wind estimates showed winds near tropical depression strength--in the 20 - 30 mph range--at 4:30 am EDT this morning. However, sea surface temperatures (SSTs) are in the 23-25 C range, which is below the 26 C threshhold usually needed for tropical storm formation. This low reminds me of the "Greek" storms Delta, Epsilon, and Zeta that formed in a similar location with similar SSTs last Fall. Today's storm may be able to spend enough time the next few days over waters just warm enough to allow it to make the transition to a subtropical storm and perhaps even a tropical storm. The system is not a threat to land right now, and will track westward towards Bermuda over the next few days.


Figure 3. Preliminary model tracks for the low 800 miles east of Bermuda.

Forecasted development north of Puerto Rico
Most of the global computer forecast models--with the notable exception of the UKMET model--have been consistently forecasting a tropical or non-tropical storm to form northeast of Puerto Rico on Tuesday or Wednesday. Today is the third day in a row the models been making this forecast, so I thought I'd finally mention it, despite my doubts about the liklihood of this happening. There is a lot of wind shear forecast to be in the vicinity of the forecasted low, so it may have a difficult time organizing into a tropical storm. If a storm does form here, it is forecast to move northward and threaten Bermuda late next week. SSTs are in the 26 - 28 C range in the area, which is warm enough to support a tropical storm.

I'll be back with up update on Sunday, unless there is a major development to discuss.

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: 642 - 592

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13Blog Index

640. guygee
3:55 PM GMT on June 25, 2006
LOL Skye, we are both talking about our sprinklers! OK, I gone now, I need to get some "outside time"...
Member Since: September 16, 2005 Posts: 0 Comments: 3174
639. guygee
3:41 PM GMT on June 25, 2006
Hey Skye - Good question. The ULL really isn't moving much, so I am going to keep watch as that big chunk of moisture gets drawn in from the SE.

I don't see the trough progressing very rapidly over the Gulf coast, so I don't think the ULL center will move much today. The ULL is slowly becoming a warm core system, and it will make the transition if it has enough time...

Talk to you later!
Member Since: September 16, 2005 Posts: 0 Comments: 3174
638. guygee
3:34 PM GMT on June 25, 2006
I just noticed that the last run of the GFDL on the map above was 8 PM yesterday, so my last comment on the GFDL really doesn't apply. The 06/25 0Z GFDL run is the latest one available.

The sun is shining again here in Satellite Beach. Precipitation here has been 0.03 inches in the 24 hours preceding Jun 24, 2006 - 07:55 AM EDT.

I think I'll go outside and work on my sprinkler system. Catch you all later!
Member Since: September 16, 2005 Posts: 0 Comments: 3174
637. Skyepony (Mod)
3:28 PM GMT on June 25, 2006
Well wrote guygee... that's what I'm seeing as well. The question of the day is~ Is the small ULL roughly south of Mobile gonna impeed the trough enough to allow the Bahama ULL to sit on the gulf stream long enough to atleast get better organized or perhaps transition to a TD? Seems it doesn't take days over the gulf stream, but it would need the better part a full day to see signifigant organization.
Member Since: August 10, 2005 Posts: 197 Comments: 38774
636. guygee
3:22 PM GMT on June 25, 2006
On the models: the BAMs are grabbing ahold of the surface circulation, which is typical but wrong in this case.

THe GFDL latches onto the current ULL, but I agree with StormJunkie that it initializes it a little too far north. If anything does develop from this, it will be around the ULL.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
635. guygee
3:18 PM GMT on June 25, 2006
Oops, that should have read "1200Z surface analysis from the Tampa NWS", above.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
634. MZT
3:17 PM GMT on June 25, 2006
An interesting thing about this system off FLA, is that although it has been suffering for days from dry air, it seems to have sucked most of the dry air out of the GOM... Actually flung it out and around, what remains is off the Georgia coast.

If another system gets close to the Gulf in the next several days, we may not need to talk about inhibitance from dry air. Just intensification prospects...

Member Since: September 24, 2005 Posts: 0 Comments: 793
633. guygee
3:12 PM GMT on June 25, 2006
Observations:
The small surface vortex riding up the FL coast is riding up what is left of the surface tropical wave axis. Surface winds are NE on the west side and SE or S on the east side. Here is a link to the 1500Z surface analysis from the Tampa NWS showing the location of the wave axis. The little surface low is riding up this axis, and is currently just SE of Melbourne, as shown in the intellicast radar loop.

At the upper levels, the Bahama ULL is centered around 25.9 N 77.8 W and appears to be drifting north. There is a spoke of dry air rotating around the Bahama ULL towards the FL coast. This could bring some breaks in the clouds and help fire up storms over the interior peninsula today.

The tropical wave that was east of the the one currently just off FL coast was severely sheared by the big central Atlantic ULL, but the remnants of this wave are sending a large chunk of moisture being pulled in from the SE from around 25 N 73 W. Below this, there is another spoke of dry air rotating around the Bahama ULL. Some convection is currently firing up SW of the ULL east of Miami, and some of this convection seems to be rotating around the ULL center in the vicinity of Andros Island.

The deep layer trough is digging into the wester GOM, while the eastward motion of the south end of the trough is lagging the motion to the north considerably. The eastern movement of the trough in the Gulf is being impeded by a small ULL roughly south of Mobile.
Upper level features were observed on the RAP WV loop.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
632. StormJunkie
3:10 PM GMT on June 25, 2006
I think the GFDL may have a handle on this system now, only problem is it initiated it too far N IMO.

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
631. Skyepony (Mod)
3:09 PM GMT on June 25, 2006
MZT~ yeah we need the rain, I'm in Melbourne, Fl. Got nothing out of it so far, it's sunny & I need to go move the sprinkler. According to UCF (& this model has proven to be pretty accurate, good on track, great on intensity) the NE is gonna get the bulk of the mess, not the SE. I'd gladly take it, but it doesn't wanna seem to dish it out here.
Member Since: August 10, 2005 Posts: 197 Comments: 38774
630. StormJunkie
3:07 PM GMT on June 25, 2006
The ULL, best seen on water vapor, is the only center this thing has. It is not over S Fla. It is over open warm water. It could work it's way down tothe surface. The convection and moisture is starting to centralize around it as it expells the last pocket of dry air it should see.
SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
629. StormJunkie
3:04 PM GMT on June 25, 2006
thel and Fanatic

Look at the WV

It looks to me like the whole thing wi going to move a little N of WNW with a turn to the NW and NNW. The floater WV also shows how much mositure is starting to get around the center of the ULL.

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
628. MZT
3:02 PM GMT on June 25, 2006
Since an ULL isn't a true tropical system, wouldn't that make it less suceptible to land interaction? IE it could keep circulating over FLA for a while and sir up moisture all over the place...

Yeah, a mess. But most people in the southeast need rain.
Member Since: September 24, 2005 Posts: 0 Comments: 793
627. Skyepony (Mod)
3:02 PM GMT on June 25, 2006
the yellow is trees down, widespread power outages. the bits of red in there is roof damage power out.

Can't link right to it. it's in here
Member Since: August 10, 2005 Posts: 197 Comments: 38774
626. Skyepony (Mod)
2:56 PM GMT on June 25, 2006
SJ, yeah it does look like the influx of dry air is being cut off again. But around 5Z it was all closed with a little dry air in the center. UCF model is still showing this to be a potental mess as it travels up through the east coast.
Member Since: August 10, 2005 Posts: 197 Comments: 38774
625. thelmores
2:53 PM GMT on June 25, 2006
looks like the llc is very near melbournes.....

this ull could spin up another surface low, which could head towards the carolina's, although mainly a rain event.....

worth watching since the ull has shead most of the dry air.....
Member Since: September 8, 2005 Posts: 0 Comments: 3805
624. MZT
2:53 PM GMT on June 25, 2006
There seems to be a large burst of convection off the Carribiean side of Nicaragua today.
Member Since: September 24, 2005 Posts: 0 Comments: 793
623. SWLAStormFanatic
2:52 PM GMT on June 25, 2006
So the ULL is over S Fl. Steve Lyons just said that it could still spin off another surface low that would trek N. Any speculations on the future of the ULL? Is it going to keep moving W into the Gulf?
622. StormJunkie
2:46 PM GMT on June 25, 2006
Just keep an eye on the ULL WSI. It has closed off the dry air. The whole area is about to become saturated once it gets that last little bit of dry air out. You can clearly see the increase in moisture around the center of the ULL. I am not saying they will ever clasify it, only that it will only start looking better now. Something like the Houston Blob.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
621. WSI
2:42 PM GMT on June 25, 2006
I think its done. I expect they will call off the flight into it this afternoon. I think we have seen all this disturbance is going to do.
620. StormJunkie
2:37 PM GMT on June 25, 2006
TD=BIG maybe Taz. Strong TS, seriously doubt it.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
619. Tazmanian
2:31 PM GMT on June 25, 2006
so this will give it a ch of a TD or strong ts right?
Member Since: May 21, 2006 Posts: 5091 Comments: 115385
618. StormJunkie
2:29 PM GMT on June 25, 2006
Sky, it actuall looks like it is trying to get rid of it's last bit of dry air. The influx has been cutoff from the S. So now the dry air to the N and E should now get worked out. It also looks like there is some decent convection just to the W of the ULL center that is fairly persistent. There is a chance that the ULL stays over the Gulf Stream for up to 48hrs. That would give it a lot of time with out the dry air.

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
617. Skyepony (Mod)
2:18 PM GMT on June 25, 2006
morning all~ Got a wopping .04" from the fizzling Blob so far... turned on the pasture sprinklers. Looks like it's gonna push some dry air over the east coast. Ya'll west of 95 look to have a better shot at rain than me. Looks like it was fed more dry air during the night.
Member Since: August 10, 2005 Posts: 197 Comments: 38774
616. lightning10
2:15 PM GMT on June 25, 2006
What a night last night here we had Tropical Force Winds...

Some odd convection this morning. Some middle level convection moving
through the southern portion of l.A. County. Dry air below this
convection has created an environment favorable for dry microbursts.
One struck the Downey area a little after 200 this morning. These
convective cells will continue until about dawn.

That exact same cell moved over Whittier where I live. I woke up it got very very windy. There was a little bit of lightning and thunder with it.
Member Since: November 24, 2005 Posts: 41 Comments: 630
615. SavannahStorm
2:10 PM GMT on June 25, 2006
Bahama Blob is becoming even more elongated, but has thrown us some storms this morning in Savannah, with another nice cell on the way as I speak.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
614. StormJunkie
2:06 PM GMT on June 25, 2006
gud, the big ULL has vortexes rotating around it. It is unlikely that one of these will develop. The ULL has to transition to a tropical system in order for anything to come out of this.

Sat Loop

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
613. gud
2:03 PM GMT on June 25, 2006
Is that a small-diameter cyclonal circulation over Miami right now? See the radar at http://www.wunderground.com/radar/radblast.asp?num=6&delay=15&scale=1.00&noclutter=0&ID=AMX&type=N0R&lat=0&lon=0&label=you&showstorms=10 or look at satellite images. It seems that cumulunimbus are flaring up around Miami while circulating around the town. The shear is very low and the water temperature quite high. Could this lead to further development, perhaps?
612. refill
2:01 PM GMT on June 25, 2006
Weather 456: The answer to your question is:
The name Ana was used in 1985, 1991, 1997 and 2003 and will come again in 2009
611. StormJunkie
1:37 PM GMT on June 25, 2006
Yup Guygee, now the B-ULL, or Bahama Upper Level Low, should move up the trough. If it stays over the Gulf Stream, and the dry air truly does get worked out, then it will at very least throw a lot of Gulf and Atlantic mositure on FLA as well as most of the E coast.

Member Since: August 17, 2005 Posts: 26 Comments: 16874
610. guygee
1:32 PM GMT on June 25, 2006
OK, bigger picture: trough is starting to dig into the Western Gulf. There is a weak ULL forming south of the FL panhandle, dropping south. The Bahama ULL is centered between Andros and Grand Bahama Island.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
609. hurricanealley
1:30 PM GMT on June 25, 2006
hello!
Member Since: March 26, 2006 Posts: 8 Comments: 971
608. StormJunkie
1:23 PM GMT on June 25, 2006
:) I spent a lot of time wathcing these vortices too.

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
607. WSI
1:21 PM GMT on June 25, 2006
Good morning all. I think the dry air has ended the chances for that system off Florida. I don't think it has enough time, and even if it did, it has some dry air to mix out first.

weathercore.com has many good links and other weather information. New is a tropical forecasting tutorial. It will help those new to tropical weather forecasting learn the basics. From there, I provide links to more in depth information.
606. StormJunkie
1:20 PM GMT on June 25, 2006
Water Vapor Loop

Look at the bigger picture Guygee.

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
605. guygee
1:19 PM GMT on June 25, 2006
I am not counting the vortices as centers any more Guygee. They will just get sheared apart by the ULL.

That's a good point StormJunkie, the pressures are so uniform, the center of the vortex can't really be much of a low pressure center.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
604. guygee
1:16 PM GMT on June 25, 2006
Also in the radar loop, you can see it...it might actually be moving more NNW, so maybe it won't come onsore in FL at all, but rather roll up the coast.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
603. StormJunkie
1:16 PM GMT on June 25, 2006
I am not counting the vortices as centers any more Guygee. They will just get sheared apart by the ULL. I think the only hope is for the ULL to transition. It has to get rid of the dry air. Also interesting, from the look of the stalled front, the ULL, may stay off shore for the next 36 to 48hrs.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
602. refill
1:13 PM GMT on June 25, 2006
I think 10N 35W is interesting. Right here in Puerto Rico we have a quiet weather...
601. LoneStarWeather
1:13 PM GMT on June 25, 2006
I agree with you, Watchingnva. I think our next storm is brewing at 10n 37w. It's already starting to get a little rotation going. I bet we see something there by the end of the day...
Member Since: September 8, 2001 Posts: 0 Comments: 436
600. guygee
1:08 PM GMT on June 25, 2006
StormJunkie - You are right, that center is very near the ULL center, but I think the circulation is at the surface now, as the low-level clouds are showing up on the visible, due to the lack of much deep convection. I go to the GHCC visible loop and zoom in on high. I seached north and south, and I can only see that one vortex off the southcentral east Florida coast. Not to say another LLC won't form today somewhere else in the system, but that is what I see right now.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
599. refill
1:03 PM GMT on June 25, 2006
I think 10N 35W is interesting. Right here in Puerto Rico we have a quiet weather...
598. guygee
1:02 PM GMT on June 25, 2006
thelmore - LOL!
The area around 30 N 53 W is looking more interesting this morning, but it is still under the big ULL, so development would probably be very slow if at all.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
597. StormJunkie
1:01 PM GMT on June 25, 2006
Guyugee, that is the ULL that is elongated, although I think it only looks elongated due to the dry air. If the dry air leaves the ULL, and it stays close to the Gulf Stream there is an outside chance it could work down to the surface.

SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
596. StormJunkie
12:58 PM GMT on June 25, 2006
Good Morning All.


From the looks of the WV the dry air to the ULL is about to be cut off.

Also interesting is the GFDL's latest run as well as the GFS seem to show the ULL hanging half on shore and half off most of the way up the coast. The GFDL show it reaching 1008 around GA.

For those who have not seen....Find all of the best free weather data on the web at StromJunkie.com. Imagery, models, windshear data, SSTs, and more. Including WU blogger storm video.

SJ

Member Since: August 17, 2005 Posts: 26 Comments: 16874
595. guygee
12:57 PM GMT on June 25, 2006
borlando - Interesting, thanks. Amazing how uniform the pressure field is...just goes to show that there will be no development of this system. I can see something in the visible loops like an elongated cyclonic circulation just offshore, with winds on the west side mostly NE, and winds on the east side mostly SE.

Due to the low clouds over most of the peninsula, we may not see the same big storms like we did yesterday, but if we get some breaks in the clouds, they could still fire up.
Otherwise, more likely moderate rain and drizzle for today.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
594. thelmores
12:54 PM GMT on June 25, 2006
well, looks like some rain today from the pesky BLOB (or lack therof), with all the onshore flow.....

certainly gonna be a humid one! :)

not sure if I could stand ST being right, so for goodness sake, we need a TS before the end of june! LOL
Member Since: September 8, 2005 Posts: 0 Comments: 3805
593. Tazmanian
12:44 PM GMT on June 25, 2006
why if i may ask
Member Since: May 21, 2006 Posts: 5091 Comments: 115385
592. MahFL
12:43 PM GMT on June 25, 2006
Is anyone else experiencing slow responces from the Wunderground website ?
Member Since: June 9, 2004 Posts: 0 Comments: 3738

Viewing: 642 - 592

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13Blog 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
43 °F
Overcast