WxWatcher007

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.

Posting because this was actually alluded to a bit this morning and we did see some hints of a possible downshear reformation that looked to be ongoing from recon. Not saying RI is happening for those lurking, but rather highlighting a possible reason we see intensification once this starts paralleling the coast. Xiaomin is an atmospheric scientist for HRD (Hurricane Research Division) at NOAA.

That'd push big rains right into CT

Final VDM. Pressure drop of 2mb but no eye information. Center a little NW. Product: Air Force Vortex Message (URNT12 KNHC)Transmitted: 19th day of the month at 19:46ZAgency: 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: 1Observation Number: 13 ( See all messages of this type for this mission. )A. Time of Center Fix: 19th day of the month at 19:05:10ZB. Center Fix Coordinates: 29.63N 71.14WB. Center Fix Location: 420 statute miles (675 km) to the WSW (244°) from Hamilton, Bermuda (U.K.).C. Minimum Height at Standard Level: 1,439m (4,721ft) at 850mbD. Minimum Sea Level Pressure: 998mb (29.47 inHg)E. Dropsonde Surface Wind at Center: From 170° at 18kts (From the S at 21mph)F. Eye Character: Not AvailableG. Eye Shape: Not AvailableH. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 48kts (55.2mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 21 nautical miles (24 statute miles) to the NE (48°) of center fix at 18:58:30ZJ. Maximum Flight Level Wind Inbound: From 149° at 61kts (From the SSE at 70.2mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 46 nautical miles (53 statute miles) to the NE (49°) of center fix at 18:50:00ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 33kts (38.0mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 51 nautical miles (59 statute miles) to the SW (227°) of center fix at 19:21:30ZN. Maximum Flight Level Wind Outbound: From 303° at 39kts (From the WNW at 44.9mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 24 nautical miles (28 statute miles) to the SW (224°) of center fix at 19:13:00ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17°C (63°F) at a pressure alt. of 1,525m (5,003ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 1,529m (5,016ft)R. Dewpoint Temp (collected at same location as temp inside eye): 13°C (55°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 Level: 850mbT. Navigational Fix Accuracy: 0.02 nautical milesT. Meteorological Accuracy: 0.5 nautical milesRemarks Section: Maximum Flight Level Wind: 61kts (~ 70.2mph) which was observed 46 nautical miles (53 statute miles) to the NE (49°) from the flight level center at 18:50:00Z

Looks like the pressure is dropping. Here's the latest center dropsonde. Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)Transmitted: 19th day of the month at 19:20ZAgency: United States Air ForceAircraft: Lockheed WC-130J Hercules with reg. number AF97-5304Storm Name: HenriStorm Number: 08 (flight in the North Atlantic basin)Mission Number: 1Observation Number: 14 ( See all messages of this type for this mission. )Part A... Date: Near the closest hour of 19Z on the 19th day of the month Highest Mandatory Level For Which Wind Was Reported: 925mb Coordinates: 29.6N 71.1W Location: 419 statute miles (674 km) to the WSW (244°) from Hamilton, Bermuda (U.K.). Marsden Square: 080 ( About ) Surface and Standard Isobaric Surfaces Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed 1000mb -20m (-66 ft) This level does not exist in this area of the storm above the surface level. 998mb (29.47 inHg) Surface (Sea Level) 26.6°C (79.9°F) 25.2°C (77°F) 170° (from the S) 18 knots (21 mph) 925mb 667m (2,188 ft) 23.0°C (73.4°F) 22.6°C (73°F) 170° (from the S) 22 knots (25 mph) 850mb 1,408m (4,619 ft) 23.0°C (73.4°F) About 18°C (64°F) No Wind Report Available For This Level Information About Radiosonde: - Launch Time: 19:05Z - About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction. Remarks Section... Dropsonde Location: Dropped in center. Lowest altitude where wind was reported: - Location: 29.64N 71.14W - Time: 19:07:16Z Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding): - Wind Direction: 170° (from the S) - Wind Speed: 23 knots (26 mph) Deep Layer Mean Wind (average wind over the depth of the sounding): - Wind Direction: 180° (from the S) - Wind Speed: 18 knots (21 mph) - Depth of Sounding: From 844mb to 997mb Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding: - Lowest 150m: 155 gpm - 5 gpm (509 geo. feet - 16 geo. feet) - Wind Direction: 170° (from the S) - Wind Speed: 21 knots (24 mph) Sounding Software Version: AEV 30404 Part B: Data for Significant Levels... Significant Temperature And Relative Humidity Levels Level Air Temperature Dew Point 998mb (Surface) 26.6°C (79.9°F) 25.2°C (77°F) 916mb 22.6°C (72.7°F) 22.1°C (72°F) 896mb 24.0°C (75.2°F) 19.1°C (66°F) 850mb 23.0°C (73.4°F) About 18°C (64°F) Significant Wind Levels Level Wind Direction Wind Speed 998mb (Surface) 170° (from the S) 18 knots (21 mph) 995mb 170° (from the S) 21 knots (24 mph) 947mb 170° (from the S) 24 knots (28 mph) 918mb 170° (from the S) 22 knots (25 mph) 889mb 200° (from the SSW) 18 knots (21 mph)