EPAC: BONNIE - Post-Tropical - Discussion

[cycloneye]

Definitely a surface closed circulation now present NNE of Caracas.

https://i.imgur.com/3oOmhJP.gif

We will get observations from Aruba / Curazao to see if the LLC moves thru them.

[aspen]

PTC2 doing the latitude limbo with the current forecast track. How low can you go. On satellite, it looks a bit higher in latitude. I assume it will eventually cross into the Epac, and may be renamed?

If it makes it into the EPac intact and formed before then, it would keep the name Bonnie, like like Otto remained Otto when it crossed over in 2016.

PTC2 is already decently close to being a TC, and it’ll have 36-42 hours over the SW Caribbean before landfall. That should be long enough for it to become at least a moderate TS, raising its chances of surviving the crossover and maybe becoming an even stronger storm in the EPac.

Thanks for your reply. What exactly is keeping the system so low in latitude?

A combination of it coming off at a pretty low latitude and strong ridging preventing it from gaining too much latitude. The ridging and typical strong June/July trades are responsible for its very fast forward speed, although it’ll slow down in the last 24-36 hours before landfall.

[ScottNAtlanta]

If it makes it into the EPac intact and formed before then, it would keep the name Bonnie, like like Otto remained Otto when it crossed over in 2016.

PTC2 is already decently close to being a TC, and it’ll have 36-42 hours over the SW Caribbean before landfall. That should be long enough for it to become at least a moderate TS, raising its chances of surviving the crossover and maybe becoming an even stronger storm in the EPac.

Thanks for your reply. What exactly is keeping the system so low in latitude?

A combination of it coming off at a pretty low latitude and strong ridging preventing it from gaining too much latitude. The ridging and typical strong June/July trades are responsible for its very fast forward speed, although it’ll slow down in the last 24-36 hours before landfall.

Once we get to August and September, these systems will be able to get further north as the Atlantic ridge shifts north.

[NDG]

Didn't realized how tall those mountains are right along the coast to the south of the possible low forming just north of Caracas, 8-9k feet tall

[underthwx]

Bout to fly out to Cabo this morning for vacation, but I'll give a short explanation what's going on with this storm.


It's very likely we have a developing llc under the convection probably somewhere around 12.5N and 66W. This is roughly 75 miles north of the current fix by NHC. This will have a significant impact on the track of the storm. 75 miles may not seem like much, but this is where the butterfly effecting comes in. To put it simply, a small change in the near term can lead drastic changes in the long term. A few good examples of this was the GFS being too far east in the short term with the tropical wave that became Agatha and Alex and thus was blowing up the storm in the Gulf. Another one was hurricane Nicholas when an old vort got spit out and moved southward and erroneously got fixed by NHC and sent the models east towards southeast Louisiana. In reality the center was further north and the storm made it's first landfall along the upper Texas coast. Finally, the probably most drastic example was Dorian's reformation to the north that changed the path from a sure death over Hispaniola to a track north of the Greater Antilles. As of now, short term steering will be dictated by old circulation to the south acting as a pseudo gyre. That circulation should die over land over the next day or two. From there the rest depends on the strength of the storm. The strong PTC 2 gets, the more it will feel the weakness. A further north PTC 2 will have more opportunity to get stronger. If that occurs this will lead to more corrections northward over time. Anyone that's confident in the current forecast shouldn't be. Model consensus is useless if it's consistently receiving bad data. Until a dominant llc has developed and been fixed and fed for at least 2 to 3 model cycles, everything is on the table now. That includes places as far east as Jamaica and western Cuba.

What to watch going forward is how satellite behaves. As of now I'm looking for what I like to call a storm awakening it's Sharingan for you Naruto fans out there. In this case a tomoe in the Sharingan is a rotating hot tower in a tropical cyclone. In this case I'm looking for a 2 tomoe awakening as 2 rotating hot towers will clue me in that this storm is approaching hurricane status. Once that northern llc takes over, I don't think it will take long as long as convection persists.

[url]https://i.ibb.co/9gLYz5w/Sharigan-Awakening.gif [/url]

Enjoy your vacation, and may you attain the six-path powers in Cabo!

[InfernoFlameCat]

I have seen TC's form a closed circulation over land more times than I can count.

Over South America?? Without trades to help it? Without the natural effect of the earths spin at such a low latitude? It would be very difficult for PTC2 to accomplish that.

Didn't say it would be easy, but we've seen storms somehow overcome such barriers and surpass them.

I stand corrected.

[Category5Kaiju]

Am seriously beginning to doubt this develops in the Atlantic. Best bet this tracks into the eastern Pacific and develops there.

As fast as this storm may be going, it still has until Saturday or so before it crosses CA, and it's already looking the best it's been on satellite right now. I personally would actually be stunned to see it not even become a NS in the Atlantic, I personally think it'll become a NS pretty soon.

[Auraem]

Chiming in from Aruba. Overcast and collapsed wind regime. This storm is extremely rare for us. The last time a storm passed to our south like this was Bret 1993. Will post updates as the day goes by.

[aspen]

What’s going on with recon? Are they not allowed to fly south of 15N due to Venezuelan airspace restrictions?

[Sciencerocks]

[wxman57]

What’s going on with recon? Are they not allowed to fly south of 15N due to Venezuelan airspace restrictions?

That is most likely the reason. ABC islands are reporting ENE wind 5-10 kts. Winds appear lower than yesterday. This will have a hard time developing an LLC until tomorrow evening in the SW Caribbean. It's still not a Gulf threat...

[wxman57]

https://imagizer.imageshack.com/img924/6229/QmwqQu.gif

I've been watching a little swirl almost on the coast of Venezuela, south of all the squalls. It's on track to move ashore in the next hour. Nothing well-defined, just a swirl.

[underthwx]

What’s going on with recon? Are they not allowed to fly south of 15N due to Venezuelan airspace restrictions?

That is most likely the reason. ABC islands are reporting ENE wind 5-10 kts. Winds appear lower than yesterday. This will have a hard time developing an LLC until tomorrow evening in the SW Caribbean. It's still not a Gulf threat...

I would think the government there would welcome the benefits of aerial recon during a tropical weather event, such as this, to keep those concerned, informed about any potential threats.

[NDG]

https://imagizer.imageshack.com/img924/6229/QmwqQu.gif

I've been watching a little swirl almost on the coast of Venezuela, south of all the squalls. It's on track to move ashore in the next hour. Nothing well-defined, just a swirl.

Simon Bolivar Int'l Airport right on the coast now reporting WNW winds, definitely a weak closed circulation just NNW from Caracas.

[Aric Dunn]

That is a closed LLC> the eastward swath of low level clouds over water near the coast to the south of LLC is very clear and straightforward.

[WiscoWx02]

Well I’ll be darned…SW and NW winds showing up down there in northern Venezuela. Shame recon can’t get in to confirm this though.

[NDG]

[MississippiWx]

https://i.imgur.com/3KHKuJf.gif

Looks classifiable to me now.
The low is just north of the coast. Land is interfering with the inflow, so not much in the way of thunderstorms on the south side.

[NDG]

https://i.imgur.com/3KHKuJf.gif

Looks classifiable to me now.
The low is just north of the coast. Land is interfering with the inflow, so not much in the way of thunderstorms on the south side.

Yes, also the MLC is just ahead to the west of the developing LLC so there's is down sloping winds over the 8-9k mountain range along the coast in the mid levels drying out the environment just offshore, thus the lack of convection.

[NDG]

Plenty of TS force winds to the north of the developing LLC found at both flight level and by SFMR.

URNT15 KWBC 291754
NOAA2 0402A PTC02 HDOB 18 20220629
174500 1343N 06627W 6949 03233 0114 +091 +097 096033 037 031 000 01
174530 1341N 06627W 6950 03233 0108 +096 +098 103027 030 034 000 01
174600 1339N 06627W 6949 03234 0109 +095 +098 105023 025 038 000 01
174630 1337N 06627W 6949 03232 0105 +098 +097 104022 023 037 001 00
174700 1335N 06628W 6948 03233 0104 +097 +096 105025 026 036 003 00
174730 1333N 06628W 6949 03232 0109 +094 +096 101026 027 034 003 01
174800 1331N 06628W 6951 03229 0110 +093 +095 100030 031 032 003 01
174830 1329N 06628W 6950 03230 0117 +088 +096 103035 036 035 001 01
174900 1327N 06628W 6951 03229 0124 +083 +097 102036 037 036 000 01
174930 1325N 06628W 6952 03228 0121 +085 +099 105038 039 034 001 01
175000 1323N 06629W 6948 03232 0120 +086 +100 110041 044 035 001 01
175030 1321N 06629W 6953 03225 0118 +088 +101 107044 046 033 004 01
175100 1319N 06629W 6948 03226 0122 +083 +102 111043 046 033 008 01
175130 1317N 06629W 6959 03222 0117 +089 +104 103039 040 032 000 01
175200 1315N 06629W 6952 03229 0118 +087 +104 101038 039 033 000 01
175230 1313N 06631W 6945 03235 0113 +090 +104 109037 038 /// /// 05
175300 1312N 06633W 6948 03232 0114 +089 +105 113037 038 040 000 01
175330 1311N 06635W 6951 03232 0121 +088 +106 112038 039 040 000 01
175400 1311N 06637W 6958 03226 0111 +095 +107 109040 040 038 000 01
175430 1310N 06640W 6952 03231 0108 +097 +107 108039 039 039 001 01