Carolina tropical depression strengthening, Caribbean disturbance disorganized

By: Dr. Jeff Masters , 3:43 PM GMT on July 19, 2008

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Tropical Depression Three continues to organize off the coast of South Carolina. Wilmington, NC long range radar shows the steady development of solid spiral bands of thunderstorms on all sides of the center, and these bands have begun bringing heavy rains to the North Carolina coast. Rainfall amounts as high as 3 inches have fallen just north of Wilmington, NC, as estimated by weather radar (Figure 1). TD 3 is over waters of marginal warmth, about 27°C, a degree above the threshold of 26°C needed to sustain a tropical storm. The warm waters are very shallow, and the Tropical Cyclone Heat Potential is near zero, meaning we're unlikely to see rapid intensification of TD 3. Wind shear is about 15 knots over the storm, and is forecast to fall below 10 knots by Sunday. There is some dry air over the Southeast U.S. that may get entrained into TD 3's circulation. TD 3 should be able to intensify into a weak tropical storm, if the center manages to remain over water. None of the models forecast that TD 3 will intensify beyond a 50 mph tropical storm, due to the relatively cool water temperatures, moderate wind shear, and the presence of dry air nearby. I think TD 3 is organizing a bit more than the models are expecting, and has a 50% chance of becoming a 50 mph tropical storm by Monday. Coastal areas of North Carolina are likely to get heavy rains from TD 3, but it remains to be seen if these rains will penetrate far enough inland to significantly alleviate moderate drought conditions that exist over eastern portions of the state. Heavy rains may also develop over South Carolina, but the main rain will probably remain offshore as the storm passes that state. TD 3 is unlikely to affect any other states, with the possible exception of Cape Cod and Nantucket, Massachusetts Monday/Tuesday.

Links to follow:
Wilmington, NC long range radar
Southeast U.S. Marine observations and forecasts
Wilmington, NC weather


Figure 1. Latest radar estimated rainfall from TD 3.

Caribbean disturbance 94L
A well-organized disturbance in the Central Caribbean (94L) is bringing heavy rain and gusty winds to Haiti and Jamaica today. Kingston, Jamaica recorded sustained winds of 31 mph at 7 am local time, but the winds have since died down. Winds at the Central Caribbean buoy south of Jamaica have been sustained at 34 mph this morning. Satellite loops show no surface circulation, and the cloud pattern is disorganized. This morning's QuikSCAT pass missed 94L. An upper-level cold low centered over Cuba is bringing about 20 knots of wind shear to the northern portion of 94L, but the southern portion of the disturbance is under only about 10 knots of wind shear. A Hurricane Hunter flight will examine 94L this afternoon.

Links to follow:
Kingston, Jamaica weather
Central Caribbean buoy

The upper-level low bringing high wind shear to 94L has weakened considerably in the past six hours, and is forecast to slide westward and continue to weaken over the next two days. Very low wind shear of 5 knots or less should be over the disturbance Sunday. The low shear combined with the warm (28.5°C) water of the Western Caribbean should allow 94L to finally organize into a tropical depression by Sunday. NHC is giving 94L a high (>50% chance) of developing into a tropical depression by Monday morning. The disturbance has time to potentially strengthen into a tropical storm with 50 mph winds before coming ashore on the Yucatan Peninsula sometime between Sunday night and Monday afternoon. Passage over the Yucatan will no doubt significantly disrupt what should be a relatively weak system, and it is unclear what threat, if any, the storm will pose to the Gulf of Mexico coast. Once it does cross into the Gulf, wind shear should be low enough to permit development. The models favor a second Mexican landfall just south of Brownsville, Texas. There is a excellent chance that 94L will bring welcome drought relief to the parched regions of Southern Texas and northern Mexico along its path, regardless of whether the system develops into a tropical storm.

Bertha sets a new record
Hurricane Bertha is now the longest-lived July hurricane on record (and the longest-lived hurricane so early in the season). Bertha has been a hurricane 7.5 days, which eclipses the previous record of 7 days held by Hurricane Emily of 2005. Bertha is also the longest-lived tropical storm on record for July (and for so early in the season), as well as the farthest east forming tropical storm and hurricane for so early in the season. I find it amazing we've had a July storm that has lasted nearly 17 days! Bertha's days are numbered, though. Bertha will reach cold water less than 70°F by Sunday, which should finally kill it.

Elsewhere in the tropics
Three of our four reliable computer models for are predicting a new tropical depression will develop off the coast of Africa 5-7 days from now. The level of tropical activity the past week has been quite remarkable, and is more typical of September than July. It's a very good thing that sea surface temperatures are more than 1°C cooler than during the record-breaking Hurricane Season of 2005. As it is, the nature of this unusually high early season activity likely means we are in for a busier than average main portion of hurricane season, August-October.

I'll have a full update Sunday morning, and perhaps a short update later today if we get a new named storm.

Jeff Masters

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4138. Akumalturtle
9:08 PM GMT on July 20, 2008
Hi folks, I'm a lurker here mostly, learning from you all because I live now in the Yucatan. I'm 65 miles south of Cancun. Just lost what little sun we had today. Looks like Dolly is going to come right over the top of us from what I can tell. I haven't quite figured out all this steering wind stuff lol.
I'll try and let you know how she comes in here. That is if my internet dish doesn't blow off the deck!
4137. TX2FL
8:41 PM GMT on July 20, 2008
4124-cheeweez..

I see that..I hope the more north it goes doesnt make it make suddon turn to the east. On another note..I'll be riding the bus by August if the season keeps on trend...
Member Since: July 14, 2008 Posts: 0 Comments: 117
4136. TX2FL
8:37 PM GMT on July 20, 2008
Quoting AirTrafficMan:
I am going to have discussions this evening with Mexican ATC and the airlines about their plans for Cancun flights tomorrow. You just never know what 45kt winds and 10 inches of rain will do to an airport that has an elevation of 20 ft above MSL. Anyone plan on flying to Cancun or Cozumel tomorrow??


I work for an airline so our operations will be studying that I'm sure so we can get the word out to passengers..boy this blew up quick!
Member Since: July 14, 2008 Posts: 0 Comments: 117
4135. Baybuddy
8:18 PM GMT on July 20, 2008
This is going to be a crappy season.
Member Since: June 26, 2006 Posts: 0 Comments: 1115
4134. naplesdreamer28
6:58 PM GMT on July 20, 2008
LA to FL need to watch Dolly, the jog North is obvious!
Member Since: July 3, 2008 Posts: 0 Comments: 242
4133. BaffinBayTx
6:50 PM GMT on July 20, 2008
I guess gas prices in my area are going to skyrocket.
Member Since: July 20, 2008 Posts: 0 Comments: 1
4132. CandiBarr
5:55 PM GMT on July 20, 2008
Quoting Weather456:
The loop I justed posted shows Bertha may skirt the Northern Yucatan.


dolly you mean?
4131. saintsfan06
5:53 PM GMT on July 20, 2008
I have no clue what I am looking at so I would like someone to explain what that swirl is just to the NE of the latest blow up in convection. AGAIN - I am just learning!

Link
Member Since: September 18, 2007 Posts: 0 Comments: 171
4130. IpswichWeatherCenter
5:42 PM GMT on July 20, 2008
Quoting KrazyKaneLove:
Bertha has circumnavigated the globe now? ROFL
Quoting KrazyKaneLove:
Bertha has circumnavigated the globe now? ROFL


lol... well bertha just got a mention on ITV ANGLIA Weather... they think that she is gonna curve and hit the uk
Member Since: April 27, 2008 Posts: 29 Comments: 2097
4129. XL
5:36 PM GMT on July 20, 2008
Just been for a drive round Grand Cayman. Still putting dow a bit of rain. There is some localised flooding (nothing horrendous from what I saw) and lots of standing water on the roads.
Member Since: July 19, 2008 Posts: 0 Comments: 92
4128. LAnovice
5:33 PM GMT on July 20, 2008
Quoting kewwestcanes:
Weater456 here you go.

http://www.nws.noaa.gov/

Thanks KeyWest
Member Since: September 7, 2007 Posts: 0 Comments: 361
4127. KrazyKaneLove
5:33 PM GMT on July 20, 2008
stormw I just read your latest update..looks like you nailed the current scenario!
Member Since: September 7, 2007 Posts: 0 Comments: 429
4126. Hhunter
5:32 PM GMT on July 20, 2008
well storm w what ya think
Member Since: August 19, 2007 Posts: 0 Comments: 2973
4125. pandorasbox
5:31 PM GMT on July 20, 2008
new blog..
4123. dipatel1
5:30 PM GMT on July 20, 2008
StormW: Any predictions on Mrs. Dolly based on what her movement is currently in a more NW direction, as to where she will be lets say tomorrow morning?



4122. JRRP
5:29 PM GMT on July 20, 2008
Quoting DestinJeff:
i think we can get to 100 pages. blog conditions are condusive for rapid posts, with very little shear and high TCHP.

jajajajajajaja
Member Since: August 16, 2007 Posts: 0 Comments: 5482
4121. kewwestcanes
5:28 PM GMT on July 20, 2008
Weater456 here you go.

http://www.nws.noaa.gov/
Member Since: August 1, 2007 Posts: 0 Comments: 23
4120. Hhunter
5:28 PM GMT on July 20, 2008


cdo definitely forming over center..may be getting lined up faster than thought...
Member Since: August 19, 2007 Posts: 0 Comments: 2973
4118. stillwaiting
5:26 PM GMT on July 20, 2008
welcome doub-aya
Member Since: October 5, 2007 Posts: 20 Comments: 4970
4117. TheWeatherMan504
5:26 PM GMT on July 20, 2008
good obsevation 456
Member Since: May 18, 2008 Posts: 2 Comments: 1042
4116. LAnovice
5:26 PM GMT on July 20, 2008
Does anyone know why they aren't showing the forecast points on the NHC's visuals - (not available at this time?) Thought they had a forecast track?
Learning - thanks
Member Since: September 7, 2007 Posts: 0 Comments: 361
4115. IcemanMC
5:25 PM GMT on July 20, 2008
4101.....that's the last thing we need Katrina/ Rita caused gas prices to increase a couple of dollars........I really don't want to pay 6-8 bucks/ gallon.........
Member Since: August 19, 2007 Posts: 0 Comments: 275
4114. Stormchaser2007
5:25 PM GMT on July 20, 2008
Quoting Weather456:
Quoting Stormchaser2007:
Quoting Weather456:
The loop I justed posted shows Bertha may skirt the Northern Yucatan.


So the center is more NW than expected?


The motion over the past 12 hours was generally northwestward, and I extrapolate that trend and it may graze or crossed the NE Tip area. Also the ULL will play a role in steering more north than expected. Refer to what happened to Ernesto in 2006 when he ULL ahead of him pulled him more north than normal and caused the track to shift from New Orleans to South Florida.


Ok thanks!! I remember the Ernesto track now....lets hope it misses the Eddy.
Member Since: June 9, 2007 Posts: 4 Comments: 15790
4113. catastropheadjuster
5:24 PM GMT on July 20, 2008
NEW BLOG
Member Since: August 24, 2006 Posts: 21 Comments: 3657
4112. KrazyKaneLove
5:24 PM GMT on July 20, 2008
Oh shoot..I was just about to post about how nice the blog was going today..No trolls, etc. I think I jinxed us
Member Since: September 7, 2007 Posts: 0 Comments: 429
4111. LAnovice
5:24 PM GMT on July 20, 2008
Quoting kewwestcanes:
They already have tropical warnings in the central GOM, right up to the LA,MI,FL coast. It's on the NWS page.

Could you send that Link please?
Thanks
Member Since: September 7, 2007 Posts: 0 Comments: 361
4110. Stormchaser2007
5:23 PM GMT on July 20, 2008
Quoting moonlightcowboy:
4058. Stormchaser, uuuumm, I didn't think of that "pun" when I posted that! LOL, yeah, just the threat is likely to cause price spikes.
LOL....yep you always gotta check your posts for some comic relief.
Member Since: June 9, 2007 Posts: 4 Comments: 15790
4108. Cavin Rawlins
5:23 PM GMT on July 20, 2008
Quoting Stormchaser2007:
Quoting Weather456:
The loop I justed posted shows Bertha may skirt the Northern Yucatan.


So the center is more NW than expected?


The motion over the past 12 hours was generally northwestward, and I extrapolate that trend and it may graze or crossed the NE Tip area. Also the ULL will play a role in steering more north than expected. Refer to what happened to Ernesto in 2006 when he ULL ahead pulled him more north than normal and caused the track to shift from New Orleans to South Florida.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
4107. Michfan
5:23 PM GMT on July 20, 2008
It will be interesting to see what the next set of model runs show. They should have a better handle on it this time around i think.
Member Since: September 7, 2007 Posts: 0 Comments: 1667
4106. dipatel1
5:22 PM GMT on July 20, 2008
If she keeps moving NW or slows down she will miss the Yuc, and if that high that is building in the southeast is not as strong then she will move northwest further up the coasts a potential impact to central and possibly the upper texas coast as far north as Galveston or central coast Corpus Cristi.
4105. jamnkats
5:22 PM GMT on July 20, 2008
Quoting AirTrafficMan:
I am going to have discussions this evening with Mexican ATC and the airlines about their plans for Cancun flights tomorrow. You just never know what 45kt winds and 10 inches of rain will do to an airport that has an elevation of 20 ft above MSL. Anyone plan on flying to Cancun or Cozumel tomorrow??


SolEstero (broadcasting from Cozumel) just updated with the mayor (presidente) of Solidaridad y Cozumel saying the port will be closed at 1pm and 5pm (last ship TO Coz at 1pm and last ship FROM Coz at 5pm). Our next update will be at 2pm. They spoke with both presidentes - of both Cozumel and Solidaridad (municipalities)
4104. stormlvr
5:22 PM GMT on July 20, 2008
I understand the concern of all those along the Gulf Coast whenever a threatening system approaches. Taking TPC to task during the first 48 to 72 hours of the forecast track is unwise as their skill scores are pretty high. Starting with the 48 hour forecast point gives a pretty good idea of environmental factors in the systems path.
Member Since: August 12, 2007 Posts: 0 Comments: 323
4103. Stormchaser2007
5:21 PM GMT on July 20, 2008
Quoting Weather456:
LOL I meant Dolly...Bertha just stuck on my mind.


456, Do you think that this might miss the Yucatan??
Member Since: June 9, 2007 Posts: 4 Comments: 15790
4102. KrazyKaneLove
5:21 PM GMT on July 20, 2008
How long til we see closed COC you think?
Member Since: September 7, 2007 Posts: 0 Comments: 429
4100. moonlightcowboy
5:21 PM GMT on July 20, 2008
4058. Stormchaser, uuuumm, I didn't think of that "pun" when I posted that! LOL, yeah, just the threat is likely to cause price spikes.
Member Since: July 9, 2006 Posts: 184 Comments: 29596
4099. IcemanMC
5:21 PM GMT on July 20, 2008
OU Shawn I recall this is not a TX storm statement, don't crawfish now.....lol
Member Since: August 19, 2007 Posts: 0 Comments: 275
4098. bekroweather
5:20 PM GMT on July 20, 2008
I think the next set of models at 18Z will have much better initialization.

But here are the links to the latest GFS and CMC.

CMC predicts a strong hurricane in the western Gulf.
4097. kewwestcanes
5:20 PM GMT on July 20, 2008
They already have tropical warnings in the central GOM, right up to the LA,MI,FL coast. It's on the NWS page.
Member Since: August 1, 2007 Posts: 0 Comments: 23
4096. philliesrock
5:20 PM GMT on July 20, 2008
Based on satellite loops it looks like Dolly will turn north for 12-18 hours due to the ULL, then turn more westward. This looks like a Texas hit to me.
Member Since: June 29, 2006 Posts: 65 Comments: 3197
4094. Cavin Rawlins
5:20 PM GMT on July 20, 2008
LOL I meant Dolly...Bertha just stuck on my mind.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
4093. TheWeatherMan504
5:20 PM GMT on July 20, 2008
Quoting Weather456:
The loop I justed posted shows Bertha may skirt the Northern Yucatan.
i

I think she is making a run for the channel.
Member Since: May 18, 2008 Posts: 2 Comments: 1042
4092. Stormchaser2007
5:19 PM GMT on July 20, 2008
Thats some blow-up.

Member Since: June 9, 2007 Posts: 4 Comments: 15790
4091. HrDelta
5:19 PM GMT on July 20, 2008
Agreed Weather456, Bertha was quite a storm, for having lasted that long, and for turning into a hurricane that far north. She will be missed. Now we watch Christobal graze the coast of the US, and the substantial threat of the newly-christened Dolly.
Member Since: October 4, 2007 Posts: 0 Comments: 451
4090. moonlightcowboy
5:19 PM GMT on July 20, 2008
4019. txalwaysprepared, Dolly is an area of a deeper, hot current with high TCHP (basically means just that - hot, deeper water). Those currents are also racing faster than the surround currents at about two feet per second faster. And, the current is over is also a good two feet deeper than the surrounding currents.

I know we all tend to think of water as being level, well, except for waves; but it's not. The earth rotates and water/currents flow and get slammed into land, etc. As they move with the earth's rotation, etc, some currents/areas will be "higher" than others.

In this case, all that means is that Dolly is in a prime spot for intensification!
Member Since: July 9, 2006 Posts: 184 Comments: 29596
4089. KrazyKaneLove
5:19 PM GMT on July 20, 2008
Bertha has circumnavigated the globe now? ROFL
Member Since: September 7, 2007 Posts: 0 Comments: 429
4088. TheWeatherMan504
5:18 PM GMT on July 20, 2008
456 DOLLY NOT BERTHA!!!!!!! LOL
Member Since: May 18, 2008 Posts: 2 Comments: 1042

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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.