NATL: GABRIELLE - Tropical Storm - Discussion

[cycloneye]

 https://x.com/philklotzbach/status/1968332427375563256

[chaser1]

The only rotation I see on visible satellite is near 19.9N/47.6W. That's way north of the best track. Models backed way off on strengthening overnight. Hopefully, this is another dud.

Fast forward a couple hours and I'd say around 19N and 48W with what would appear as a WSW vector.

[sasha_B]

The NHC's upgrade is sensible regardless of the poor satellite presentation at the moment. Gabrielle met the convective criteria to be called a tropical cyclone earlier this morning, when the first advisory was issued, and the data now support 35-40kt winds. It'll be interesting to see how it holds together over the next 12-24 hours, though, given the downward trend in intensity guidance (and the especially sharp dropoff in support on the GFS). Good news for Bermuda, less so for those hoping for the Atlantic basin to make a dramatic comeback.

[Sciencerocks]

The main LLC is strong and suggest tropical storm but yeah convection isn't very good. I'd say 91L was more deserving but I believe both are deserving. Should see strengthening as it moves out of the MDR over the next 3-7 days and probably a hurricane north of the windwards.

[MGC]

"Although the system is at best marginally well defined," This from the NHC discussion this morning is the understatement of the season. Why the rush to upgrade? Gabby looks terrible this morning like she just got home from drinking all night. At least there is something marginal to track today........MGC

[aspen]

I think we all owe an apology to Odette ‘21. A new contender for the worst looking Atlantic TC of all time just dropped.

[LarryWx]

I bet Bastardi will have a thing or two to say about this upgrade.

Followup:

JB was surprisingly quiet. All he said was this: “Now, the red-hatched area has been designated Tropical Depression 7, posing a threat to Bermuda but not the U.S.”

But then he immediately mentioned a possible unexpected “side-show Bob” to form off the SE US.

[chaser1]

I think we all owe an apology to Odette ‘21. A new contender for the worst looking Atlantic TC of all time just dropped.

Winner of "post of the day"

[ElectricStorm]

Convection isn't anywhere close to the center, I'm also surprised they were so quick to upgrade this one. I'd be interested to hear why this one got classified but a couple of previous invests (like 99L a few weeks ago) didn't when a couple of them seemed to have closed centers and much better convection than Gabrielle does.

I think this will struggle mightily over the next several days but could find better conditions after it begins to recurve. Hurricane is possible if it can survive that long, but we'll see.

[WaveBreaking]

That upper level low took a bite out of Gabrielle's convection

[cycloneye]

Winds increased to 45kt at 18z Best Track:

AL, 07, 2025091718, , BEST, 0, 190N, 475W, 45, 1005, TS

[Woofde]

Convection isn't anywhere close to the center, I'm also surprised they were so quick to upgrade this one. I'd be interested to hear why this one got classified but a couple of previous invests (like 99L a few weeks ago) didn't when a couple of them seemed to have closed centers and much better convection than Gabrielle does.

I think this will struggle mightily over the next several days but could find better conditions after it begins to recurve. Hurricane is possible if it can survive that long, but we'll see.

Yeah I completely agree, there have been multiple other invests with stronger cases for being a TC than this has now. The circulation is elongated and rough looking.

The scatterometer passes I've seen today are... questionable, to say the least. Visible satellite data is messy as well. I read the forecast discussion and it doesn't read with much confidence. There is always going to be a high degree of subjectivity with marginal storms (and people upset about each case), but some consistency one way or the other would be preferred.

[StormWeather]

That upper level low took a bite out of Gabrielle's convection


https://i.imgur.com/yszGCVK.jpeg

I think that whole thing IS Gabrielle.

[sasha_B]

The 21z advisory will very soon offer some clarity regarding the upgrade in intensity for what appears, at least superficially, to be a marginal tropical cyclone. Objective and subjective Dvorak estimates as of 18z both agree that this is too disorganised to classify as of 18z, but I trust the NHC's judgement here - they tend to be conservative about naming storms, and if there were data to support calling Gabrielle an open wave or a TD, surely the best track & forecast discussions would reflect that.
In fact, the intensity forecast for +12h on the first advisory for TD Seven this morning not only verified, but was surpassed by 10 kts. That doesn't suggest a system on the verge of falling apart, to me.

[AnnularCane]

The 21z advisory will very soon offer some clarity regarding the upgrade in intensity for what appears, at least superficially, to be a marginal tropical cyclone. Objective and subjective Dvorak estimates as of 18z both agree that this is too disorganised to classify as of 18z, but I trust the NHC's judgement here - they tend to be conservative about naming storms, and if there were data to support calling Gabrielle an open wave or a TD, surely the best track & forecast discussions would reflect that.
In fact, the intensity forecast for +12h on the first advisory for TD Seven this morning not only verified, but was surpassed by 10 kts. That doesn't suggest a system on the verge of falling apart, to me.

I don't know if it answers the question or not, but apparently there was a center relocation.

[mitchell]

"Although the system is at best marginally well defined," This from the NHC discussion this morning is the understatement of the season. Why the rush to upgrade?

They literally answer the question in the very same sentence. "...there is enough data to support an initial
intensity of 40 kt"

[Nimbus]

I bet Bastardi will have a thing or two to say about this upgrade.

Followup:

JB was surprisingly quiet. All he said was this: “Now, the red-hatched area has been designated Tropical Depression 7, posing a threat to Bermuda but not the U.S.”

But then he immediately mentioned a possible unexpected “side-show Bob” to form off the SE US.

Sideshow Bob had a Shakespearean actress for a mother so maybe the forecast is going to be a Tempest play?
In any case Gabby6 is closing off far north and following that ULL will create an earlier recurve which is good news.

[MEANINGLESS_NUMBERS]

I bet Bastardi will have a thing or two to say about this upgrade.

Followup:

JB was surprisingly quiet. All he said was this: “Now, the red-hatched area has been designated Tropical Depression 7, posing a threat to Bermuda but not the U.S.”

But then he immediately mentioned a possible unexpected “side-show Bob” to form off the SE US.

Sideshow Bob had a Shakespearean actress for a mother so maybe the forecast is going to be a Tempest play?
In any case Gabby6 is closing off far north and following that ULL will create an earlier recurve which is good news.

The Tempest is widely believe to have been inspired by the discovery of Bermuda which was contemporaneous to its writing. Fitting given this storm's course.

[Sciencerocks]

Looks like the northern part of the trough has closed off and is blowing up convectoin east and northeast of it. Probably will become better organized and strengthen over the next 24-36 hours at a slow pace before it reaches the subtropics and possibly becomes a cane.

[StormWeather]

Oh my goodness! It’s actually starting to look like a TC now?!
The 2025 Atlantic Hurricane Season can actually produce a TC? I’m shocked!