Bahamas Blob update

By: Dr. Jeff Masters , 8:17 PM GMT on July 05, 2006

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An area of disturbed weather over the Bahama Islands is associated with an upper-level low pressure system. This low is kicking up some strong thunderstorms over the Bahamas and Cuba, but has not improved in organization today. The low is cold-cored, and is making the slow transition to a warm-cored system. It needs to have a warm core in order to develop into a tropical storm. It typically takes three or more days sitting over warm water for this process to happen (let's call today day two of its existence). Wind shear is down to 5-20 knots as of 2pm EDT, which is marginally favorable for development. Water temperatures are very favorable, 28 - 29 C. However, there is little thunderstorm activity near the center of circulation, which is southeast of Key Largo, FL. All the thunderstorm activity is well away from the center, making it unlikely that we'll see a tropical depression today or tomorrow. One of the key signs that a cold-cored system is making the transition to warm-cored is that one has substantial thunderstorm activity near the center of circulation.

The big question is if the center of circulation will be over water or land Thursday and Friday. Right now, it appears that the center is moving north-northwest, and will be over the Florida Peninsula Thursday. Most of the models indicate that the center will continue moving north-northwest, and stay over the Florida Peninsula most of Thursday and Friday. Should the center emerge into the Gulf of Mexico, or remain off the East Coast of Florida, we could see a tropical or subtropical depression by Friday. The low is expected to get picked up by a strong trough of low pressure emerging off the East Coast Friday, then get swept up the coast this weekend. Both the GFS and UKMET models predict that the low will from into a tropical or subtropical depression south of North Carolina by Saturday, and bring tropical storm-force winds to the North Carolina Outer Banks on Saturday and Massachusetts' Cape Cod on Sunday. If you have plans to be either place this weekend, keep a watchful eye on the tropics! This situtation is very similar to what we had at the end of June, when we almost had Tropical Storm Beryl hitting eastern North Carolina.


Figure 1. Current satellite image of the blob of disturbed weather over the Bahamas.

The rest of the tropical Atlantic is quiet today.

Jeff Masters

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327. hurricane23
3:24 PM GMT on July 07, 2006
hey guys just checking in....whats up?
Member Since: May 14, 2006 Posts: 8 Comments: 13841
326. guygee
1:53 PM GMT on July 06, 2006
BTW, I hope the trough pushes quicky off of the east coast, so the people of the Northeast get spared another round of unwanted rains from all that tropical moisture streaming up in front of the trough.
Member Since: September 16, 2005 Posts: 0 Comments: 3188
325. Cregnebaa
1:51 PM GMT on July 06, 2006
The Cape Verde storms are the worst for us, Ivan annihilated us in 2004. Later on in the season a lot of storms spawn around here or too the south and they also can be a bother.
Anything like Katrina is not too much of a worry for us as it's to far North
Member Since: October 19, 2005 Posts: 6 Comments: 323
324. guygee
1:50 PM GMT on July 06, 2006
What I thought I was watching late last night/early morning was the FL ULL getting stretched out under southerly flow, with the northern part of the ULL getting pulled north over interior FL, with the southern part of the ULL escaping the worst of the southerly flow and entering the Gulf. Some of the model runs were calling for this scenario, with the convection and the associated upper-level high over the Bahamas getting sheared out in front of the trough, leaving behind the remnants of the ULL in the Gulf.

I'm wondering now if the models have exaggerated the amplitude of the east-coast trough. I don't see any big spokes of vorticity coming down to help it dig into FL, as predicted. We are left with a small Keys blob, with a possible surface circulation west of the convection, from what I am seeing. Will this small area develop and survive through tonight? Warm SSTs and lowering shears in its immediate vicinity are in its favor, but with its small size, and with drier air and 20+ kt shear to its west, it won't take much in the way of adverse conditions for us to soon be watching the last little "poof" of our tiny Keys blob.
Member Since: September 16, 2005 Posts: 0 Comments: 3188
323. sayhuh
1:46 PM GMT on July 06, 2006
Nothing to see here... [car wreck in the tropics]. Nothing in the models, nothing in the MSLP, nothing from the NHC.

Nothing.
322. NaplesPatty
1:45 PM GMT on July 06, 2006
Dr. Masters has a new blog
321. gninraelyrt
1:44 PM GMT on July 06, 2006
Florida is such a dangerous state to live in in late summer, but here's an interesting question for you. The Carribean islands are scattered all around Florida. Now, imagine that there were no islands whatsoever around Florida. Would these weather disturbances be more of a threat to Florida, or would they simply just simply find there way out of the gulf and into the Atlantic waters? I tend to think that waves coming from the east would pose the most threat, whereas systems developing west of Florida would be marginally threatening. Is this how you see it? Or is this too abstract to deal with?
319. Cregnebaa
1:33 PM GMT on July 06, 2006
Under that blob under Cuba at the moment, very grey, low clouds, an inch of two of rain and some nice lightening, reminds me of Ireland.
Member Since: October 19, 2005 Posts: 6 Comments: 323
317. Stormy2day
1:25 PM GMT on July 06, 2006
Is that anything in central Atlantic?
Member Since: June 29, 2006 Posts: 0 Comments: 306
315. gninraelyrt
1:02 PM GMT on July 06, 2006
Yep! There's more to this earth than water. Air, temperature, and water must work in unison to create one of earths most amazing weather phenomenons. I'm from the midwest, but have to admit that watching weather is my 2nd favorite passtime. Keep posting folks! That Bahama system is taking it's time and it appears that the development is occuring too close to land to become a Beryl. But hey, we should just enjoy watching the oven (Gulf of Mexico and Carribean coaster waters) cooking up popcorn. Popcorn's less disastrous too. Let's worry about convection in August, eh?
313. fire635
1:01 PM GMT on July 06, 2006
I certainly see a developing system in the southeaster gulf
Member Since: June 24, 2006 Posts: 0 Comments: 492
312. ricderr
12:56 PM GMT on July 06, 2006
I must be missing something here. I understand the center to be over land and am seeing no convection there. Where do you propose the center to be?
Member Since: June 27, 2006 Posts: 676 Comments: 22276
308. K8eCane
12:25 PM GMT on July 06, 2006
not much development of the blob expected unless it gets back over the atlantic then we will see what it does
Member Since: April 26, 2006 Posts: 5 Comments: 3222
306. chessrascal
12:17 PM GMT on July 06, 2006
what about that storm at 25 W and 82 N
305. fredwx
12:14 PM GMT on July 06, 2006
The upper level low appears to be weakening and is currently over the Florida Keys. At the surface there is a trough extending from a weak surface low near Tampa S-SW to the Yucatan Channel. There remains widespread showers from the NW Caribbean Sea across Cuba to the Bahamas and across South Florida. This system is moving northward at about 10 mph without any indication of tropical cyclone development.

Surface Chart
Member Since: June 8, 2005 Posts: 221 Comments: 261
304. StormJunkie
12:13 PM GMT on July 06, 2006
Morning all. Looks to be a stormy day in the southeast this afternoon, especially with the lack of cloud cover over much of the SE now. This should allow the day time heating to really fire off some potent storms this afternoon.

For those who have not seen, StormJunkie.com has a new Quick Links page to help you find the information you need quickly.

Back to work. See ya'll later.
SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
303. chessrascal
12:12 PM GMT on July 06, 2006
any answers?
302. chessrascal
12:11 PM GMT on July 06, 2006
Does anyone think that area near key west has any potetial. It is easy to view on the zoom satellite.(whith the radar on.)
300. Stormy2day
11:43 AM GMT on July 06, 2006
Tampa Bay...
Pressure took a nose dive from 1:30-7 yesterday (typical), cloud build up - bark and no bite.
This morning, winds are WNW (calm) - typical pattern is for east winds in the morning and west in the afternoon.
Current forecast is for the standard summer macro ..."30% chance of isolated afternoon tstorms"

-stormy
Member Since: June 29, 2006 Posts: 0 Comments: 306
299. thelmores
11:37 AM GMT on July 06, 2006
mornin everybody.....

looks like most of the models have something forming off the carolina coast in a couple days....

will be interesting too see this develop, and is somewhats believable since it is not just the cmc.....which has developed almost everything.....

guess we shall see! :)
Member Since: September 8, 2005 Posts: 0 Comments: 3805
297. dnalia
11:30 AM GMT on July 06, 2006
It rained like hell here in Miami yesterday, and there are thunderstorms around here this morning. Must have been from the Blob, huh?

I guess rainy season is now in full swing.
296. bappit
11:25 AM GMT on July 06, 2006
Cuba link is for jphurricane. Not awake.
Member Since: May 18, 2006 Posts: 10 Comments: 6147
295. bappit
11:21 AM GMT on July 06, 2006
Cuba.
Member Since: May 18, 2006 Posts: 10 Comments: 6147
294. Stormy2day
11:15 AM GMT on July 06, 2006
Good Morning!
What is that out in central atlantic? Around 55/30 - anything?
Member Since: June 29, 2006 Posts: 0 Comments: 306
292. denvan
11:05 AM GMT on July 06, 2006
I agree. Looks like our little blob may be getting ready to graduate to a... what does a blob become before it becomes a TD?

I saw somebody use the term "flare" for the big splash of stormy weather over Cuba, which is a nice term for an area of activity that flares up but is a long way from being a blob.

But what about a blob that starts to get organized and begins to rotate around a center / show banding / etc. - like Alberto just before it got called up to the big leagues by the NHC?

I'd use the term "spinner", but I already love the term "fish spinner", which could be a Category 5 as long as it doesn't threaten land. Or "twister", but that's a tornado. "Looper" perhaps? Maybe "turner"? Maybe "Uberblob" or "Blob goes to college". Anyway, this one looks like it's going to college - maybe even with a scholarship.
291. MahFL
10:54 AM GMT on July 06, 2006
Sails1, I agree, proberbly just create some thunderstorm activity though.
Member Since: June 9, 2004 Posts: 0 Comments: 3805
290. sails1
10:20 AM GMT on July 06, 2006
Wow, if you look closely, the ULL has just emerged off the FL Pen around Marco Island. It appears to be moving with a more west componet. Now it appears to have some organized thunderstorm activity since it has hit the warm waters of the SE GOM. This may be a feature to keep our eyes on for today. What do you guys think?
Member Since: May 26, 2003 Posts: 0 Comments: 72
289. chefjeff
9:28 AM GMT on July 06, 2006
correction : It's a broad surface low .
288. chefjeff
9:09 AM GMT on July 06, 2006
Upper level low in my back yard, Cuba blob being pulled up with it. I'm in for a rainy day.
287. aquak9
8:53 AM GMT on July 06, 2006
Midnight on the ITCZ....send your camels to bed...

(only us old folks are gonna get that one)
Member Since: August 13, 2005 Posts: 175 Comments: 26513
286. Trouper415
8:15 AM GMT on July 06, 2006
Great image there ScienceCop.

Hows your evening going? guygee as well.
Member Since: September 22, 2005 Posts: 5 Comments: 637
285. ScienceCop
8:12 AM GMT on July 06, 2006
MIDNIGHT on the ITCZ -- July-5/6 2006



284. guygee
8:03 AM GMT on July 06, 2006
Strange summer, July fronts coming down into the FL peninsula...

Excerpts:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
315 AM EDT THU JUL 6 2006

.DISCUSSION...

.CURRENT...UPPER LEVEL VORTEX APPEARS TO BE WEAKENING OVER SOUTH FLORIDA AS IT CONTINUES ITS SLOW DRIFT NORTH. ISOLATED TO SCATTERED NOCTURNAL MARINE SHOWERS AND STORMS WERE MOVING NORTH THROUGH THE MARINE ZONES FROM JUPITER INLET TO FLAGLER BEACH...WITH BETTER COVERAGE ALONG AND SEAWARD OF THE WEST WALL OF THE GULF STREAM. MOVEMENT IS INDICATIVE OF DEEPENING SOUTHERLY FLOW AS STEERING FLOW ADJUSTMENTS ARE BEING REALIZED AS A RESULT OF THE VEERING SYNOPTICS.
[...]
.DAY1 (TODAY-TONIGHT)...INFLUENCE OF THE UPPER LEVEL VORTEX WILL GIVE WAY TO A SIGNIFICANT SHORTWAVE MOVING OUT OF THE OHIO VALLEY APPROACHING THE SOUTHEAST AND MID ATLANTIC. IT WILL BE RESPONSIBLE FOR PUSHING A FRONTAL BOUNDARY INTO NORTH FLORIDA BY FRIDAY MORNING. THUS THE CURRENT SURFACE RIDGE AXIS WILL BE SHUNTED SOUTH OF THE FORECAST AREA PROMPTING THE GRADUAL TRANSITION TO A SOUTHWEST STEERING FLOW BY THIS AFTERNOON.
[...]
.DAY2 AND DAY3 (FRIDAY-SATURDAY)...WEAK FRONTAL BOUNDARY SLIDES FROM NORTH FL INTO CENTRAL FL ON FRIDAY AND WILL REMAIN A FOCUS FOR CONVECTION INTO SATURDAY. UPPER TROUGH AXIS TO DIP SOUTH ACROSS THE PENINSULA ON FRIDAY AND WILL PROVIDE ADDITIONAL SUPPORT.
[...]
Member Since: September 16, 2005 Posts: 0 Comments: 3188
283. melli
6:18 AM GMT on July 06, 2006
JFlorida - it appears the blob is in a wind shear dead zone - although some of is being pulled north (caught by the trough over the eastern US??)- http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8wvir.html

The 'shear tendency' for the area in discussion, will drop rapidly, making things interesting...

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8sht.html

Looking at the water temps....looks ripe for a baddie, of course, the wind shear is ripping everything apart.
http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/2006185gosst.png

I haven't been watching the gulf the last few days, but I thought nothing was happening (no churning TS), yet the water temps decreased (marginally, but visibly).

282. thunder01
5:58 AM GMT on July 06, 2006
The following is an excerpt from the Monterey, CA AFD from this PM. It references typhoon Ewiniar
and the potential for it to bring a rare rain event to coastal Norcal and also the possibility of a stronger W. Pac. cyclone next week.


GFS WANTS TO MOVE
THE STORM WEST OF JAPAN AND STALL IT AS THE STORM MISSES THE TROUGH
MOVING OUT OF CHINA. THE EURO HAS THE STORM RECURVING INTO THE
WESTERLIES BY SUNDAY. THUS IF THIS STORM IS TO HAVE AN IMPACT ON
THE DEVELOPING TROUGH OFF CA IT WOULD MOST LIKELY BE IN THE WED TO
THU TIME FRAME. THE IMPACTS WOULD MOST LIKELY BE TO HAVE A
STRONGER AND DEEPER TROUGH OFFSHORE CA BY THIS TIME WITH MUCH COOLER
TEMPERATURES AND POTENTIAL BREAKUP OF THE MARINE LAYER AND CHANCE
FOR RAIN ALONG THE NORTH COAST AS INDICATED BY THE MODELS. ANOTHER
INTERESTING FEATURE IS THAT THE EURO HAS AN EVEN STRONGER TYPHOON
IN ALMOST THE EXACT LOCATION AS EWINIAR NEXT WED. IT HAS A CENTRAL
PRESSURE OF 955 MB ON A VERY COURSE GRID. LETS HOPE THIS IS MODEL
MAGIC AT LEAST FOR OUR FRIENDS IN OKINAWA AND JAPAN AND POSSIBLY
TAIWAN.
281. cjnew
5:47 AM GMT on July 06, 2006
thats interesting
Member Since: July 22, 2005 Posts: 84 Comments: 2779
277. Tazmanian
5:16 AM GMT on July 06, 2006
Posted By: hurricane23 at 10:06 PM PDT on July 05, 2006.
edit yea for sure.i wish u could look over ur post before u post it.also wish we could use large images

tell aron in his blog that you would like to have some in like that ok
Member Since: May 21, 2006 Posts: 5091 Comments: 115439

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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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