WxWatcher007

We’re on the cusp of a historic event

Corrected VDM Product: Air Force Vortex Message (URNT12 KNHC)Corrected: This observation corrected a previously corrected observation.Transmitted: 20th day of the month at 12:06ZAgency: United States Air ForceAircraft: Lockheed WC-130J Hercules with reg. number AF97-5304Storm Name: HenriStorm Number & Year: 08 in 2021 (flight in the North Atlantic basin)Mission Number: 4Observation Number: 05 ( See all messages of this type for this mission. )A. Time of Center Fix: 20th day of the month at 11:41:10ZB. Center Fix Coordinates: 29.87N 73.65WB. Center Fix Location: 388 statute miles (624 km) to the SSE (164°) from Cape Hatteras, NC, USA.C. Minimum Height at Standard Level: 1,439m (4,721ft) at 850mbD. Minimum Sea Level Pressure: 1000mb (29.53 inHg)E. Dropsonde Surface Wind at Center: From 275° at 33kts (From the W at 38mph)F. Eye Character: Not AvailableG. Eye Shape: Not AvailableH. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 37kts (42.6mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 54 nautical miles (62 statute miles) to the N (351°) of center fix at 11:24:00ZJ. Maximum Flight Level Wind Inbound: From 85° at 43kts (From the E at 49.5mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 66 nautical miles (76 statute miles) to the NNW/N (349°) of center fix at 11:20:00ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 59kts (67.9mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 47 nautical miles (54 statute miles) to the SE (134°) of center fix at 11:55:00ZN. Maximum Flight Level Wind Outbound: From 240° at 62kts (From the WSW at 71.3mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 45 nautical miles (52 statute miles) to the SE (134°) of center fix at 11:54:30ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 1,523m (4,997ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 24°C (75°F) at a pressure alt. of 1,520m (4,987ft)R. Dewpoint Temp (collected at same location as temp inside eye): 12°C (54°F)R. Sea Surface Temp (collected at same location as temp inside eye): Not AvailableS. Fix Determined By: Penetration, Wind, Pressure and TemperatureS. Fix Level: 850mbT. Navigational Fix Accuracy: 0.02 nautical milesT. Meteorological Accuracy: 1 nautical mileRemarks Section: Maximum Flight Level Wind: 62kts (~ 71.3mph) which was observed 45 nautical miles (52 statute miles) to the SE (134°) from the flight level center at 11:54:30Z

Recon is going through some of the convection so keep that in mind, but Henri looks robust. Small area with 55-62kt FL winds and unflagged 58-59kt SFMR.

Seems odd to me that it has intensification north of NC.

Per the overlays, it looks like the center of Henri is just west of the deepest convection.

I think so too. Maybe not central LI yet, but I don't think the trend west is quite done yet. This one also had much shorter lead time. Usually we're tracking a CV for 10 days or so before landfall. Just a few days ago we were arguing whether this was even worth talking about lol.

998.5 mb extrapolated by recon at ~5k ft.

Makes track all the more important. I can already see part of the subforum filling up the thread with bust calls because they expected cane gusts 150 miles from the center

Recon has descended and will be heading into Henri shortly. Edit: note that since we have active watches up now, the NHC will issue intermediate advisories to update things like wind speed, pressure, and heading at 8am/2pm/8pm/2am.

Yes, those are from around 2am (surprised I didn't see them then) Consistent and deep convection helps a lot in getting a system vertically stacked. What's critical is that the convection is able to wrap upshear (in this case, to the west) to form a complete eyewall. Once you have a stable eyewall it's game on. Re-upping a great illustration from Twitter. Courtesy of Andy Hazelton.

Still tilted for sure, but let's wait for recon to see where the actual center is. It was embedded a bit deeper into the convection than expected yesterday, and we wouldn't have known that if not for the actual recon fixes. In the meantime, we do have some relatively new MW images that show a tilted, but respectable system. Like yesterday, there's a mid level eye feature, but there's still some tilt between the LLC and MLC. You're right though, it can't take off until those align.

We went from not expecting much to hurricane watches along the New England coast. What a season so far...

Recon currently doing the dropsonde/upper level sampling and low level recon is en route. Still a lot to be sorted out on final landfall location and nature of the turn toward the coast i.e. is there a loop like some guidance wants to do. That will make a big difference obviously on who sees the worst conditions.

Enjoy. Still unsure whether I’m chasing this or not.

18z EPS

Clearly evident from the improvement on IR, but shear is analyzed to be decreasing per CIMSS. From 32kts earlier to 20kts now. (note the NHC analyzed 25kts earlier)

ADT estimate has come up substantially. No surprise given the evolution on IR. The only hesitation is we don't know what things look like under the hood. We can't currently tell if the convection is being wrapped upshear in an eyewall or how tilted it is.

I know I keep saying it, but this is a very impressive satellite presentation. Really wish recon were out there.

High level recon is happening now to examine the overall environment and low level recon will probably begin again in a few hours.

18z Euro

From the time the center pulled itself back from the brink of decoupling earlier today, both visible and IR have improved gradually in presentation, even as shear continues this evening. Hard to tell what's happening inside without recon, but new microwave images are coming in a few hours.

This. Tropical is a lot different from the storms we usually see. In the right setup, you can get huge totals in a broad area, even from a weak or decaying system. We've actually seen a lot of these in recent years in the US.

It has held up very well against the shear today.