WxWatcher007

Setting aside Francine, there’s a strong operational model signal for that SE coast area I’ve been highlighting to develop as soon as this weekend. Will need to watch how far north that tracks.

Yeah east side is looking pretty solid with the latest data. Let’s see what happens with future fixes. The eye looks well defined on radar.

First VDM came in with a pressure of 975mb, but again, nothing particularly impressive on the winds front.

Extrapolated pressure down to 969.2mb in the latest data batch. Edit: 968.3 extrapolated in the next set of data. Not seeing any impressive wind data yet, however.

The eye is evident on KHGX radar, but it’s hard to assess the actual structure at this distance. A new recon flight has just taken off so we’ll see what they find. Hurricane models continue to be very aggressive on on balance in the hours right before landfall with a strong inner core about 10mb deeper than the current pressure. Very deep convection continues at/near the center, and you can see how the jet interaction is helping this ventilate efficiently.

Now at 85mph/979mb. Core quickly coming together.

So far, the organization phase has continued without much disruption. As many here noted, now that Francine is accelerating away from the western Gulf coastline and no longer competing with the MCV like convection as it was earlier, it is in a more moist environment and taking advantage of very high OHC. Here you can see persistent deep convection—the kind that led to the early development of an eye yesterday—rotating into the center. Aloft, winds are responding with continued pressure falls and clear organization of a new inner core. Recon is now finding FL winds peaking between 85-89kts and a dropsonde confirmed pressure of 980mb. Critically, the latest VDM had this remark: EYEWALL HAS 75 PERCENT COVERAGE AROUND THE EYE AND IS SIGNIFICANTLY MORE ORGANIZED THAN ON PREVIOUS PASS The next few hours will be interesting. The earlier hurricane models got very aggressive while other guidance was more modest, due to the impact of dry air entrainment and shear. For now at least. The runway looks the clearest it has been for some level of takeoff, but time is limited. A more hostile environment before landfall awaits.

Also, in LA. Will post updates as I can.

Finally able to look at stuff. We’re starting to see more substantial pressure falls and perhaps structural improvements as drier air mixes out, but evidence suggests that the vortex is a bit tilted in response to shear. As @40/70 Benchmark wrote earlier, tonight is the time when we likely see a peak when most favorable conditions align. It’s delicate though—dry air entrainment could slow or halt any significant intensification tonight. I don’t think the vortex tilting matters as much yet. The organization of the inner core has an impact on tomorrow’s landfall intensity imo.

In Gonzales, LA, which is SE of Baton Rouge. Will post when I can. Not terribly enthused but we’ll see what happens tonight. Long day of travel but I think I’m in a good spot for now at least.

This is WxWatcher007 reporting live from Gonzales, LA, just southeast of Baton Rouge. It was a long travel day—much longer than I thought at just under 2,000 miles, as I decided to adjust my staging point well east of Lafayette before my flight early this morning. Here the vibe is quite relaxed, much more than usual. Perhaps it’s the fact that Louisiana has been a magnet for some of the strongest hurricanes in recent memory. In fact, on my way to Gonzalez I passed through Iowa, LA, where I spent hours in the northeast eyewall of the extraordinary beast that was Laura. Francine is now a hurricane, and at the risk of sounding like Josh I’m not terribly enthused. Francine is intensifying, but it is fighting dry air and now shear as it makes the turn NE and heads toward the coast. Tonight is when more significant intensification could occur so I’m watching closely. Dry air and shear could easily blunt that. It’s warm and humid here with some light rain and occasionally gusty winds. I should be able to rest tonight as the action is subject to take place tomorrow. I’m closely watching the track. I think I’m in a good spot, and I chose this location in large part for its highway access to quickly get west or east if necessary. Baton Rouge is 30 minutes west. New Orleans is an hour east. By contrast, Morgan City is 90 minutes south. Obviously it’s closer to the coast so best of luck to the chasers there. I’d rather not have to report from Mississippi tomorrow, but we’ll see. As is usually the case, I’ll post when I can. @MillvilleWx is in contact with me and will let y’all know I’m ok if I lose power/cell service.

I think the early development of an eye surprised everyone, but the current issues are not surprising. It’s important to remember that despite the exceptionally high level RI systems we’ve seen since 2017, for most TCs development and intensification are not linear, and development and intensification can be two separate things. Nascent eyes are just that—yeah they can herald taking off or intensification, but they’re fragile because developing a mid and then fully developed eye is part of the development stage. When convection started declining from the peak earlier that was a flag that intensification was likely to slow. Dry air is going to be nearby because of both the boundary to the north and the continental dry air that’s often accompanying TCs in the Gulf. I think the key thing to watch is organization not intensity (read: wind). Are pressures continuing to drop? Is the eye ragged, or becoming wrapped fully with convection? Is the RMW tightening and are we seeing greater temperature contrasts in the eye? That’s going to tell us what direction things are going. Tonight the signals are mixed, not uncommon of systems at this stage of development.

Yeah I think it’s one of those things where the broader circulation isn’t quite aligned with whatever lower level center wants to become the primary. I think given recon and radar that the area seeing significant pressure drops NW of the original low level spin is the leader in the clubhouse, but there’s still some organizational work to do before this can really go. The big pressure drop and visible appearance are eye opening to me though.

For now at least, there’s a nascent eyewall. Product: Air Force Vortex Message (URNT12 KNHC)Transmitted: 9th day of the month at 17:22ZAgency: United States Air ForceAircraft: Lockheed WC-130J Hercules with reg. number AF98-5308Tropical Depression: Six (flight in the North Atlantic basin)Mission Number: 3Observation Number: 08 ( See all messages of this type for this mission. )A. Time of Center Fix: 9th day of the month at 16:45:10ZB. Center Fix Coordinates: 23.69N 95.85WB. Center Fix Location: 186 statute miles (299 km) to the SE (146°) from Brownsville, TX, USA.C. Minimum Height at Standard Level: 1,387m (4,551ft) at 850mbD. Minimum Sea Level Pressure: 996mb (29.42 inHg)E. Dropsonde Surface Wind at Center: From 140° at 5kts (From the SE at 6mph)F. Eye Character: Open in the westG. Eye Shape & Diameter: Circular with a diameter of 20 nautical miles (23 statute miles)H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: Not AvailableI. Location & Time of the Estimated Maximum Surface Wind Inbound (Undecoded): NAJ. Maximum Flight Level Wind Inbound: From 308° at 31kts (From the NW at 35.7mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 6 nautical miles to the SW (219°) of center fix at 16:43:30ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 47kts (54.1mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 55 nautical miles (63 statute miles) to the NE (47°) of center fix at 17:02:00ZN. Maximum Flight Level Wind Outbound: From 133° at 58kts (From the SE at 66.7mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 12 nautical miles (14 statute miles) to the NE (44°) of center fix at 16:49:00ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 16°C (61°F) at a pressure alt. of 1,523m (4,997ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 20°C (68°F) at a pressure alt. of 1,524m (5,000ft)R. Dewpoint Temp (collected at same location as temp inside eye): 18°C (64°F)R. Sea Surface Temp (collected at same location as temp inside eye): Not AvailableS. Fix Determined By: Penetration, Radar, Wind, Pressure and TemperatureS. Fix Levels (surface & flight level centers within 5nm of each other): Surface and 850mbT. Navigational Fix Accuracy: 0.02 nautical milesT. Meteorological Accuracy: 1 nautical mileRemarks Section: Maximum Flight Level Wind: 58kts (~ 66.7mph) which was observed 12 nautical miles (14 statute miles) to the NE (44°) from the flight level center at 16:49:00Z

Very true. There’s always a lot to learn. Turning closer to home, the 12z GFS isn’t as exotic as that happy hour run, but I think it’s more “realistic” in how we’d get something up here. A spin up off the SE coast as the ridge builds in over the top and has no escape route as the ridge slides east. Obviously fantasy range, but I’ve highlighted the SE window for a while now.

A substantial drop in extrapolated pressure between passes on that new apparent center under the deep convection. From just over 1001mb to 995.6mb. Again this extrapolated, so more of an estimate. Still, that’s very impressive.

I’ll be interested in seeing 18z more because I think the recon data will be included, but as the NHC notes the SHIPS output is quite robust.

Not sure when we’ll get a VDM, but recon is finding a much tighter and more organized center in that deep convection. Winds aren’t terribly strong, but it’s the organization that matters.

Maybe a touch more NE, but the real critical factor imo will be how strong an inner core the system has as it’s approaching the coast. If it’s a weak inner core, shear could cause last second weakening as the vortex gets tilted and drier air gets imparted. You can see on the HWRF how the core is only half complete. Other models are closer to closed but not quite there and as a result pressures are lower. I’d just caution that we don’t have a well defined center yet, so both final track and especially intensity are far from settled matters. Shear and dry air lurk, but on the other side of the equation we see very strong convection and western Caribbean like OHC along the the projected track of the system that should favor continued deep convection.

That’s the kind of signal where the right track could cause extremely efficient ventilation. Or, any deviation from that “ideal” track blasts the system right before landfall. Things look like they’re a go for intensification later, and it’s kind of impressive we’re getting this with the rest of the Gulf under high shear. ULAC saves the day I guess.

Still some uncertainty on the trough interaction so that’s not surprising