ATL: Tropical Depression Fay

[Evil Jeremy]

Alot of energy flowing to the newly formed blob as we get ready for the D-Max. Tonight's recon should provide some answers.

[Aric Dunn]

The more I look at long range radar out of San Juan...the more I think the center can't be south of the radar site. If there is one...it's either on the same latitude or perhaps even north of SJU.

Will be very interesting to see what recon finds...

It's blob-a-thon 5000 tonight. Follow the bouncing blob...all blobs all the time.

Will the next blob be the one that gets the low-level circulation?

Stay tuned!

MW

well actually yeah ok ..

[A1A]

Alot of energy flowing to the newly formed blob as we get ready for the D-Max. Tonight's recon should provide some answers.

What is the D-Max and what is its significance?

[HURAKAN]

[tailgater]

Looks like it is going to take a more southern path over PR than I expected. I also thought it would sort of scoot by just north of Hispaniola, but looking like that could be more inland than I expected too. But... very hard to tell until they get a good center fix and more significant surface features - which could be happening now as I believe Derek pointed out with some convergence showing up. It looks good on sat and convection seems to be expanding still... but it sure isn't showing us much on radar, at least not yet. I think we'll have to wait until it gets beyond the islands before the models get a better grip on what 92 will do. As Hurakan said, without reliable initialization of the models, they are not going to help us much... any small initial position errors just get magnified into huge errors as they crunch the numbers to predict future positions.

For those interested, I do have the PR radar loop with metars/buoys/ships overlaid on the vis sat image (ir at night) on my site. Maybe it will show us more as 92L approaches PR in the next few hours.

http://orionweather.net/index.php?content=radar.html


For our friends on the islands... stay safe and keep us posted.

Excellent radar loop, nice spin with feeders just a tad east of where wx57 said just a bit earlier.

[orion]

I suspect that my "apparent circulation" may be illusory. With longer range radar imagery, especially, small-scale occurences such as storm cell propagation or shallow cells dipping under the radar beam can make it seem like there's broader rotation when there really is no such happening. Hence why I always use the term "apparent" if I'm uncertain. BTW, I think that "apparent circulation" is better than this over-used "eddy" term.

- Jay

Yeah, I agree... I have been watching that area for a while. However, the surface ob there at VI now shows the wind swinging around to out of the southeast as the "apparent circulation" passes just south of it. And, it looks now like even a broader apparent circulation. Additionally, the wind speed jumped from 5 to 15 kts.

[AtlanticWind]

The more I look at long range radar out of San Juan...the more I think the center can't be south of the radar site. If there is one...it's either on the same latitude or perhaps even north of SJU.

Will be very interesting to see what recon finds...

It's blob-a-thon 5000 tonight. Follow the bouncing blob...all blobs all the time.

Will the next blob be the one that gets the low-level circulation?

Stay tuned!

MW

I thought the same , the rader echos look like the center would be NE of san Juan.

[funster]

Weird - it looks like it is trying to ooze itself around.

[ROCK]

I dont think I have ever seen a invest grow an intense appendage like that before..... very strange looking.....

[Dean4Storms]

One of the freakish looking invests I've seen. I believe the LLC is very broad and it will be some time before a clear defined center gets established. If the LLC is near where we all generally agree ENE of SJPR then the MLC is well displaced to the ESE and it could hinder this LLC from getting better organized for a while longer.

[Extremeweatherguy]

NHC wind overlay on the visible loop seems to indicate that the LLC is indeed just NE of Puerto Rico...

[Blown Away]

[img][/img]

If 92L's circulation center is just off the N coast of PR then it is following the models track very closely. Not due W into PR or WSW into the Caribbean. Based on this model run SFL is looking pretty good for now, that's pretty good agreement down the road.

[HURAKAN]

[cheezyWXguy]

Weird - it looks like it is trying to ooze itself around.

Those new bursts are directly over the llc, it appears. The dmax should be helpful with this one tonight, and tomorrow should be the day things finally occur. Convergence is excellent, divergence is excellent, and convection is popping over a developing wnw moving llc. Once again, I DO NOT THINK THIS WILL HIT THE DR, ONLY BRUSH BY TO THE NORTH. And if this is the case, we should have a pretty quick developing system in the next couple of days.

[orion]

Someone said earlier that it looks like 92L broke a spiral band. And... that's where this new blob is oozing.

[weatherguru18]

Alot of energy flowing to the newly formed blob as we get ready for the D-Max. Tonight's recon should provide some answers.

What is the D-Max and what is its significance?

Ok, I'm going to try here. Somebody feel free to add to what I say...

The D-Max or Diurnial Maximum is a period just before sunrise (usually about 5 or 6 am) when thunderstorms are most prevelent. Why is this? Thunderstorms thrive off latent heat. Latent heat, the best I can describe it, is the "heat" given off when an ice cube goes from a solid to a liquid. It has to give off heat to make a phase change. This is latent heat. Latent heat is most prevelent at night because the air is cooler and more condensation can occur. The latent heat is derived from the gas (water vapor) going from a gas to a liquid. In order for this to happen, the water vapor, a gas, must give off heat to make the change. That's why we see convection or thunderstorms fire up during the overnight hours. Anybody else care to elaborate?

[NEXRAD]

I don't know if I'd call the apparent circulation off the NE tip of Puerto Rico a "LLC" yet. On radar, I'm not really seeing much circulation there, and I checked the limited surface observations. There are higher dew-points behind the convective line that passed through Saint Croix than ahead of it. I'm wondering if the NW winds for San Juan and Sly winds for Saint Croix are more suggesting boundary or warm-front like action rather than any circulation.

- Jay

[tpr1967]

I think the center is developing near the island of Vieques. Just east of puerto Rico.
Near 18.1N 65.4W.

[Praxus]

One of the freakish looking invests I've seen.

and of course we can't forget the famous

[NEXRAD]

I think the center is developing near the island of Vieques. Just east of puerto Rico.
Near 18.1N 64.4W.

If a center is developing, then this would be my best current estimate. Composite radar imagery is showing the small, scattered, showers south of Ern Puerto Rico and Vieques to be moving east.

- Jay