ATL: HANNA - Remnants - Discussion

[Aric Dunn]

Perhaps the plane is also interested in sampling the area out ahead of the area of lowest pressure.

Definitely avoiding the center.

[Nuno]

I don’t think the NHC will upgrade it to TD today/tonight but tonight would be the ideal time to initiate PTC advisories. I would expect 75% of the TX coast to have TS watches and warnings by midnight.

Has a set criteria ever been explained for initiation of PTC advisories? It seems there are several instances where a PTC would be useful and the NHC just rarely seems to issue them.

[HurricaneBrain]

If an unclassified storm is forecast to become classified and produce tropical storm conditions on land (or is expected to make landfall as a tropical storm) within 48 hours, that’s when the PTC designation should come in. Given that it’s likely we will see Hanna make landfall in TX as a tropical storm Friday night, it would meet the criteria to be designated a PTC by midnight.

I don’t think the NHC will upgrade it to TD today/tonight but tonight would be the ideal time to initiate PTC advisories. I would expect 75% of the TX coast to have TS watches and warnings by midnight.

Has a set criteria ever been explained for initiation of PTC advisories? It seems there are several instances where a PTC would be useful and the NHC just rarely seems to issue them.

[Dean_175]

Perhaps the plane is also interested in sampling the area out ahead of the area of lowest pressure.

Definitely avoiding the center.

Why?

[floridasun78]

plane report below td wind that area still looking

[Aric Dunn]

Perhaps the plane is also interested in sampling the area out ahead of the area of lowest pressure.

Definitely avoiding the center.

Why?

Idk.. squirl moments ? lol

[wxman57]

Possibility that you might not get much rain from this in southwest Houston. Could be a sharp gradient to your south/sw.

I got 1.25" today in about 30 minutes with a passing thunderstorm. Yard is happy now. Will the recon plane turn south or west in the next few minutes?

[Aric Dunn]

Couple good towers over the center. hopefully Recon does a SE to NW pass.

[CrazyC83]

I agree with the assessment that it is not a TC right now. However, are we in the range for watches to be needed?

[wxman57]

No upgrade. Too disorganized. 90% after 48 hrs (right as it reaches the TX coast, I guess). Probably becomes a TS tomorrow night.

[CrazyC83]

No upgrade. Too disorganized. 90% after 48 hrs (right as it reaches the TX coast, I guess). Probably becomes a TS tomorrow night.

That's what I think: 90/90. PTC 8 depends on if we are in watch range.

[cycloneye]

80% / 90%

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Jul 22 2020

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Storm Gonzalo, located over the central tropical Atlantic.

1. Data from the Air Force Hurricane Hunters and surface observations
indicate that an area of low pressure over the central Gulf of
Mexico is gradually becoming better defined. However, the
accompanying shower and thunderstorm activity is still poorly
organized. Environmental conditions appear conducive for slow
development of this system, and a tropical depression is likely to
form during the next day or so as it moves west-northwestward at
about 10 mph. Interests in the western Gulf of Mexico should
monitor the progress of this system, as watches or warnings could be
required for portions of the coasts of Texas and Louisiana tonight
or on Thursday.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

Forecaster Cangialosi

[Aric Dunn]

80% / 90%

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Jul 22 2020

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Storm Gonzalo, located over the central tropical Atlantic.

1. Data from the Air Force Hurricane Hunters and surface observations
indicate that an area of low pressure over the central Gulf of
Mexico is gradually becoming better defined. However, the
accompanying shower and thunderstorm activity is still poorly
organized. Environmental conditions appear conducive for slow
development of this system, and a tropical depression is likely to
form during the next day or so as it moves west-northwestward at
about 10 mph. Interests in the western Gulf of Mexico should
monitor the progress of this system, as watches or warnings could be
required for portions of the coasts of Texas and Louisiana tonight
or on Thursday.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

Forecaster Cangialosi

So the Circ was defined but the convection was not organized enough.

next several hours before sleepy time could see a good burst of convection .. starting with what is popping now over the center.

[zhukm29]

Pretty large blowup is occurring as we speak:

[Horn1991]

Pretty large blowup is occurring as we speak:

https://i.ibb.co/6BMB5tG/goes16-ir-91-L-202007222102.gif

Watch those clouds out to the West of the center start to wrap.

[Nimbus]

Sharp drop in pressure near the center.


https://www.ndbc.noaa.gov/show_plot.php ... _label=EDT

[wxman57]

No upgrade. Too disorganized. 90% after 48 hrs (right as it reaches the TX coast, I guess). Probably becomes a TS tomorrow night.

That's what I think: 90/90. PTC 8 depends on if we are in watch range.

They will almost certainly start PTC advisories in the morning (5am EDT), or it may be clearly a TD by then. Lots of observation sites in its path tonight.

[NXStumpy_Robothing]

One of the very few benefits of a GOM system - there's lots of observation sites and buoys for data collection.

We'll see what 91L can do with the approaching dmax.

[wxman57]

Levi has a new video uploaded:
[url]
https://www.youtube.com/watch?time_cont ... e=emb_logo[/url]

[Aric Dunn]

Sharp drop in pressure near the center.


https://www.ndbc.noaa.gov/show_plot.php ... _label=EDT

yeah the center should go straight over that buoy.