WxWatcher007

Adding D26 for good measure

It just seems so off to me on intensity. Henri looks like it could hold its own when it runs into that shear later, and it should have a favorable environment for a while as it parallels the coast. I know though that small systems can really get torn apart when encountering significant shear.

Maybe, but depending on the track I think you'd see areas that are already fairly saturated that could see trees go down easier. Of course, if it's a CT hit expect us to be knocked back to the 18th century

No update from the NHC at 8am, but Grace is clearly on its way to hurricane status, if it isn't there already. Recon is impressive so far and the northern side hasn't been sampled. It has a closed eye on recon! Product: Air Force Vortex Message (URNT12 KNHC)Transmitted: 18th day of the month at 11:54ZAgency: United States Air ForceAircraft: Lockheed WC-130J Hercules with reg. number AF98-5307Storm Name: GraceStorm Number & Year: 07 in 2021 (flight in the North Atlantic basin)Mission Number: 13Observation Number: 05A. Time of Center Fix: 18th day of the month at 11:29:30ZB. Center Fix Coordinates: 19.10N 81.30WB. Center Fix Location: 14 statute miles (22 km) to the SSE (161°) from George Town, Cayman Islands (U.K.).C. Minimum Height at Standard Level: 1,375m (4,511ft) at 850mbD. Minimum Sea Level Pressure: 994mb (29.36 inHg)E. Dropsonde Surface Wind at Center: From 255° at 8kts (From the WSW at 9mph)F. Eye Character: ClosedG. Eye Shape: Elliptical (oval shaped)G. Orientation of Major Axis in Elliptical Eye: 20° to 200° (NNE to SSW)G. Length of Major Axis in Elliptical Eye: 20 nautical miles (23 statute miles)G. Length of Minor Axis in Elliptical Eye: 12 nautical miles (14 statute miles)H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 40kts (46.0mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 52 nautical miles (60 statute miles) to the WNW (295°) of center fix at 11:06:00ZJ. Maximum Flight Level Wind Inbound: From 283° at 60kts (From the WNW at 69.0mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 4 nautical miles to the S (190°) of center fix at 11:24:30ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 56kts (64.4mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 4 nautical miles to the ESE (117°) of center fix at 11:31:00ZN. Maximum Flight Level Wind Outbound: From 240° at 64kts (From the WSW at 73.6mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 6 nautical miles to the ESE (122°) of center fix at 11:31:30ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 16°C (61°F) at a pressure alt. of 1,538m (5,046ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 24°C (75°F) at a pressure alt. of 1,522m (4,993ft)R. Dewpoint Temp (collected at same location as temp inside eye): 14°C (57°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: 1.5 nautical milesRemarks Section: Maximum Flight Level Wind: 64kts (~ 73.6mph) which was observed 6 nautical miles to the ESE (122°) from the flight level center at 11:31:30Z

Probably too in the weeds this far out but even a weaker system could be rough given the slow (relative to climo) motion projected on the guidance would bring prolonged rain and wind, not to mention terrible timing with regard to tides this weekend.

I can't post the tweet, but it looks like 70mph sustained was measured at a CWOP site on Grand Cayman.

Trend west continues from what I've seen so far this morning. Definitely become less of a long shot and more of a legitimate threat to the northeast given the 500mb look. A long way to go though.

Just one more addition, here's the reanalysis by Eric Webb of 500mb anomalies for NE hurricanes since 1900. Image courtesy of his Twitter. Note the dates at the bottom, and compare/contrast with the 500mb pattern being shown even on the Euro.

I love it when a TC makes my forecast look good. That Monday post looks pretty good right now for Henri lol. Still a long way to go, but that 500mb look is how we get our tropical up here. Last 8 GEFS runs Euro operational trend at 500mb

The story of Henri in two gifs GEFS last 8 runs Operational GFS last 8 runs It's easy to see the 500h changes here, and it's been similar across the guidance--even the Euro/EPS which tries its hardest to effectively kill Henri as it's making its turn to the west has been adjusting a bit to a steering pattern where we see a trough try to capture rather than kick Henri as it ends its westward jog and turns northward as ridging over eastern Canada seals off an escape route to the NE. In fact, the guidance has been playing catch up IMO from forecasting TC genesis to now, with Henri consistently more organized and further south/west than forecasts. Doesn't mean it'll stay that way, but it can have significant downstream implications. Although the location of Henri's development and potential northward swing is almost totally outside climatology from what I've seen with regard to how we get our storms (they're usually deeper in the tropics and CVs), the potential steering pattern fits the method of how we tend to see our TC impacts with ridging over SE Canada and troughing in the Great Lakes/Mid Atlantic. Again, even the operational Euro (note the EPS were the first to hint at a East Coast threat days ago before pulling back) in its last four 00z runs have trended toward a similar 500h look that lends itself to a close call or direct impact. The signal looks legit to me, but 5 days out I know a lot can change. I'm watching 1) whether the south/west trend continues as Henri runs into a more favorable environment the next 12 hours that will make it more resilient when it encounters more northerly shear later tonight, 2) whether the trough continues to be oriented in a way that creates a capture rather than a kick, and 3) whether the ridge continues to become more pronounced on guidance.

For the few EPS members that don’t kill off Henri, the trend is west as well.

Euro is not even in the same ballpark as the other guidance. It could be right, as shear should increase again in the next 24 hours or so per NHC, but it’s curious that it has no interest in intensifying Henri when it’s actually in a favorable environment and quite frankly has done well in the face of prior shear in a less organized state. We’ll see what the ensembles say and what Henri looks like later this morning but the presentation is excellent on IR and radar once again tonight with a nice convective blowup over the center and at least a mid level eye on radar.

Yeah, it’s a bit west from 12z. All the major global guidance so far and the GEFS shifted west tonight. Doesn’t mean it’ll stay that way, but it’s definitely intriguing.

Ukie is west and an eastern NE hit on the crude maps.

There’s obvious spread among the GEFS but there’s a definitive shift west this cycle through hour 102.

Very first thing I noticed. It seems like a sensitive forecast to be based on intensity, and the next 24-48 hours are really tricky because moderate shear could increase Wednesday/Thursday and small storms can be more impacted by that.

There’s your weenie GFS run of the season. Basically a perfect “capture” to slingshot it into eastern NE as ridging over the top closes the escape route. Interesting, but show me the ensembles.

Newest VDM now has an eye that’s open to the north and northwest. Clearly still organizing per recon.

Based on the vortex data message (VDM) from 30 minutes ago, it’s not an eye. Definitely more organized than its ever been as a system though.

Tropical Storm Henri Discussion Number 8 NWS National Hurricane Center Miami FL AL082021 500 PM AST Tue Aug 17 2021 Henri appears to be gaining strength. Satellite images show banding features becoming increasingly curved, especially on the east side of the system, and an eye feature has been occasionally seen in radar images from Bermuda. The upper-level outflow is also well established to the north and east of the center. The center itself is estimated to be located near the western edge of the convection, but it is possible that a new center is forming farther east. The initial intensity is raised to 55 kt following the Dvorak classification from TAFB. The initial wind radii has been expanded outward based on an earlier ASCAT pass. The tropical storm appears to have slowed down, and the latest initial motion estimate is 255/2 kt. A subtropical ridge over the western Atlantic is building eastward to the north of Henri, and this feature should steer the storm westward at a slightly faster pace during the next two to three days. After that time, the ridge is expected to weaken and shift farther east as a cut off low or negatively-tilted trough develops over the northeast U.S. This change in the steering pattern should cause Henri to turn northeastward between Bermuda and the east coast of the U.S in the 72-120 h period. There is a fair amount of spread in exactly when and where Henri makes this turn and the GFS and EC ensembles have some members not far offshore of New England and Atlantic Canada. Overall, the guidance has shifted westward again this cycle, and the NHC track forecast has been adjusted accordingly from days 3 to 5. The northwesterly shear currently affecting Henri is subsiding, which should allow the storm to gain a little more strength tonight. However, a round of moderate northerly shear is expected to setup over Henri on Wednesday and Thursday and that will likely temporarily end the opportunity for strengthening. Although this shear would typically cause some weakening, the combination of warm SSTs and increasing mid-level moisture could offset the negative influences of the shear. By Friday and over the weekend, the shear is expected to lessen again and since the other environmental factors are predicted to remain favorable for the storm, strengthening is shown from days 3-5. This forecast is above the previous one, and lies fairly close to the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 17/2100Z 30.4N 64.2W 55 KT 65 MPH 12H 18/0600Z 30.3N 65.5W 60 KT 70 MPH 24H 18/1800Z 30.2N 67.0W 60 KT 70 MPH 36H 19/0600Z 30.2N 68.6W 60 KT 70 MPH 48H 19/1800Z 30.3N 70.0W 60 KT 70 MPH 60H 20/0600Z 31.0N 71.1W 60 KT 70 MPH 72H 20/1800Z 32.0N 71.5W 65 KT 75 MPH 96H 21/1800Z 35.5N 69.6W 70 KT 80 MPH 120H 22/1800Z 39.1N 65.2W 70 KT 80 MPH $$ Forecaster Cangialosi

65mph/997mb at 5pm Now expected to become a hurricane by the NHC

I know I know I’m asking a lot

Henri has an excellent presentation on both visible and radar. Radar shows a nearly fully developed eyewall, though it's hard to be 100% sure without recon confirming it's not a mid level feature.

I can’t see anything yet with the EPS but a quick glance of the Euro showed perhaps a less pronounced PRE signal as Henri passes SE?

I know…you riled me up. That comment was more with regard to winter wx threats lol. In all seriousness, I always appreciate hearing your tropical thoughts. I know I sometimes come off as waffling with my tropical posts but I have two good reasons it: 1) I’ve been burned too many times making declarations, especially during my early tropical tracking days 2) I’m a lawyer and I’m trained to think and write that way