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Tropical Storm Henri


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2 minutes ago, Baroclinic Zone said:

 

Good AM AMWx.   I think a track right up Naggy Bay is gaining traction just looking at guidance this AM.  I feel the runs curling into W LI are too aggressive.  Only way I see those occurring is if Henri remains weak and can be impacted more by that trough.  If it becomes a stronger storm, the trough won't have as great an impact.

It’s going to hook to the northwest at some point but the timing is obviously everything. 

Typically you tend to hedge a little eastward on northeast TCs because of the prevailing westerlies tend to nudge the troughs along, but there’s some transitory blocking to the northeast on this one so we will have to see if that holds or it weakens just a bit as we get closer. There’s also a bit of a kicker shortwave in the plains that could affect the ULL that is trying to steer this thing. 

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Latest dropsonde. Need to see more to make sure it's actually representative of the wind field but this would have it close to hurricane status. 

 

Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 20th day of the month at 12:14Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5304
Storm Name: Henri
Storm Number: 08 (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 07 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 12Z on the 20th day of the month
Highest Mandatory Level For Which Wind Was Reported: 925mb
Coordinates: 29.3N 73.1W
Location: 394 statute miles (634 km) to the NE (42°) from Nassau, Bahamas.
Marsden Square: 080 ( About )
 
Surface and Standard Isobaric Surfaces
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1006mb (29.71 inHg) Surface (Sea Level) 23.4°C (74.1°F) 21.9°C (71°F) 190° (from the S) 63 knots (72 mph)
1000mb 54m (177 ft) 22.6°C (72.7°F) 21.3°C (70°F) 190° (from the S) 64 knots (74 mph)
925mb 734m (2,408 ft) 21.0°C (69.8°F) 19.9°C (68°F) 210° (from the SSW) 66 knots (76 mph)
850mb 1,464m (4,803 ft) 17.6°C (63.7°F) 17.1°C (63°F) No Wind Report Available For This Level

Information About Radiosonde:
- Launch Time: 11:54Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...
 
Dropsonde Location: Dropped in maximum wind band.

Highest altitude where wind was reported:
- Location: 29.31N 73.06W
- Time: 11:54:31Z

Lowest altitude where wind was reported:
- Location: 29.34N 73.04W
- Time: 11:56:50Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 195° (from the SSW)
- Wind Speed: 67 knots (77 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 210° (from the SSW)
- Wind Speed: 60 knots (69 mph)
- Depth of Sounding: From 844mb to 1006mb

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: 190° (from the S)
- Wind Speed: 65 knots (75 mph)

Sounding Software Version: AEV 30404
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level Air Temperature Dew Point
1006mb (Surface) 23.4°C (74.1°F) 21.9°C (71°F)
979mb 21.0°C (69.8°F) 19.7°C (67°F)
951mb 22.6°C (72.7°F) 19.8°C (68°F)
850mb 17.6°C (63.7°F) 17.1°C (63°F)
 
Significant Wind Levels
Level Wind Direction Wind Speed
1006mb (Surface) 190° (from the S) 63 knots (72 mph)
997mb 190° (from the S) 64 knots (74 mph)
985mb 195° (from the SSW) 71 knots (82 mph)
951mb 200° (from the SSW) 64 knots (74 mph)
933mb 210° (from the SSW) 63 knots (72 mph)
927mb 210° (from the SSW) 67 knots (77 mph)
920mb 215° (from the SW) 62 knots (71 mph)
911mb 215° (from the SW) 64 knots (74 mph)
900mb 215° (from the SW) 57 knots (66 mph)
886mb 225° (from the SW) 61 knots (70 mph)
860mb 235° (from the SW) 52 knots (60 mph)
855mb 240° (from the WSW) 56 knots (64 mph)
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1 minute ago, wkd said:

Seems billion dollar disasters are a dime a dozen nowdays.

With the rate of inflation and prices of materials, a couple collapsed decks makes for a billion dollar disaster.

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9 minutes ago, Baroclinic Zone said:

I feel the runs curling into W LI are too aggressive. 

I tend to give a little more weight to the globals, particularly the euro in this situation than I might in the deep tropics.  If we can mostly all agree that the weak trough over the MA and the strength and position of the ridging over the top will be the key determining factors, I think you'd have to give deference to those models designed to handle such.  JMO.  At present GFS and euro seem to be on the eastern side of the current model envelope.

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Just now, ORH_wxman said:

It’s going to hook to the northwest at some point but the timing is obviously everything. 

Typically you tend to hedge a little eastward on northeast TCs because of the prevailing westerlies tend to nudge the troughs along, but there’s some transitory blocking to the northeast on this one so we will have to see if that holds or it weakens just a bit as we get closer. There’s also a bit of a kicker shortwave in the plains that could affect the ULL that is trying to steer this thing. 

Correct.  But I think the stronger the storm gets over the next 24hr, the less impacted it will be by the trough, leading to a further E track than say what the NAM/Ukie show.  I'm leaning towards what the GFS/Euro show for track looking at the upper air pattern.  It's really the ideal pattern to a TC to hit us with the blocking in place as well.  I think we see 12z guidance on the W edge shift E today.  My goalposts are Canal over to New London, CT for landafll.

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6 minutes ago, WxWatcher007 said:

Latest dropsonde. Need to see more to make sure it's actually representative of the wind field but this would have it close to hurricane status. 

 

Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 20th day of the month at 12:14Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5304
Storm Name: Henri
Storm Number: 08 (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 07 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 12Z on the 20th day of the month
Highest Mandatory Level For Which Wind Was Reported: 925mb
Coordinates: 29.3N 73.1W
Location: 394 statute miles (634 km) to the NE (42°) from Nassau, Bahamas.
Marsden Square: 080 ( About )
 
Surface and Standard Isobaric Surfaces
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1006mb (29.71 inHg) Surface (Sea Level) 23.4°C (74.1°F) 21.9°C (71°F) 190° (from the S) 63 knots (72 mph)
1000mb 54m (177 ft) 22.6°C (72.7°F) 21.3°C (70°F) 190° (from the S) 64 knots (74 mph)
925mb 734m (2,408 ft) 21.0°C (69.8°F) 19.9°C (68°F) 210° (from the SSW) 66 knots (76 mph)
850mb 1,464m (4,803 ft) 17.6°C (63.7°F) 17.1°C (63°F) No Wind Report Available For This Level

Information About Radiosonde:
- Launch Time: 11:54Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...
 
Dropsonde Location: Dropped in maximum wind band.

Highest altitude where wind was reported:
- Location: 29.31N 73.06W
- Time: 11:54:31Z

Lowest altitude where wind was reported:
- Location: 29.34N 73.04W
- Time: 11:56:50Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 195° (from the SSW)
- Wind Speed: 67 knots (77 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 210° (from the SSW)
- Wind Speed: 60 knots (69 mph)
- Depth of Sounding: From 844mb to 1006mb

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: 190° (from the S)
- Wind Speed: 65 knots (75 mph)

Sounding Software Version: AEV 30404
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level Air Temperature Dew Point
1006mb (Surface) 23.4°C (74.1°F) 21.9°C (71°F)
979mb 21.0°C (69.8°F) 19.7°C (67°F)
951mb 22.6°C (72.7°F) 19.8°C (68°F)
850mb 17.6°C (63.7°F) 17.1°C (63°F)
 
Significant Wind Levels
Level Wind Direction Wind Speed
1006mb (Surface) 190° (from the S) 63 knots (72 mph)
997mb 190° (from the S) 64 knots (74 mph)
985mb 195° (from the SSW) 71 knots (82 mph)
951mb 200° (from the SSW) 64 knots (74 mph)
933mb 210° (from the SSW) 63 knots (72 mph)
927mb 210° (from the SSW) 67 knots (77 mph)
920mb 215° (from the SW) 62 knots (71 mph)
911mb 215° (from the SW) 64 knots (74 mph)
900mb 215° (from the SW) 57 knots (66 mph)
886mb 225° (from the SW) 61 knots (70 mph)
860mb 235° (from the SW) 52 knots (60 mph)
855mb 240° (from the WSW) 56 knots (64 mph)

Seems to support FL wind data. I would go 70 mph

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2 minutes ago, Baroclinic Zone said:

Correct.  But I think the stronger the storm gets over the next 24hr, the less impacted it will be by the trough, leading to a further E track than say what the NAM/Ukie show.  I'm leaning towards what the GFS/Euro show for track looking at the upper air pattern.  It's really the ideal pattern to a TC to hit us with the blocking in place as well.  I think we see 12z guidance on the W edge shift E today.  My goalposts are Canal over to New London, CT for landafll.

Still think C LI to PVD is the window 

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8 minutes ago, radarman said:

I tend to give a little more weight to the globals, particularly the euro in this situation than I might in the deep tropics.  If we can mostly all agree that the weak trough over the MA and the strength and position of the ridging over the top will be the key determining factors, I think you'd have to give deference to those models designed to handle such.  JMO.  At present GFS and euro seem to be on the eastern side of the current model envelope.

Agreed, The global models are currently solidly to the east of the mesos. Ukie is prob the furthest west of the globals right now....landfall near RI/CT border.....and basically all of the mesos are all west of the Ukie. There's really no overlap right now between the two camps. That makes me want to hedge more toward the globals given the synoptic importance of the trough/blocking features.

I do think the globals can come west a little more. The mesos cannot be entirely chucked. They will handle the internal convection better and that can help steer the storm a little west by pumping up the WAR to the east a little.

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8 minutes ago, WxWatcher007 said:

North of the Gulf Stream? It's warm, but not high octane stuff. 

It's more timing though. The environment for quick intensification looks better to me a little further south. 

natlanti.c.gif

2021230at.jpg

Thanks for posting actual SST's! Sometimes we get too caught up in the SSTA's but we need to remember the water temperatures needed for tropical systems to strengthen. Despite the waters off the coast being warmer than average they are still several degrees below what is generally required for strengthening. Not only this but the depth of the isotherms is just as important, especially in slow movers. 

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1 minute ago, weatherwiz said:

Thanks for posting actual SST's! Sometimes we get too caught up in the SSTA's but we need to remember the water temperatures needed for tropical systems to strengthen. Despite the waters off the coast being warmer than average they are still several degrees below what is generally required for strengthening. Not only this but the depth of the isotherms is just as important, especially in slow movers. 

I have been hammering the upwelling issue as well. The depth of warm water just south of New England is shallow. Add in East NE winds and upwelling rapidly cools the surface.

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Just now, Ginx snewx said:

I have been hammering the upwelling issue as well. The depth of warm water just south of New England is shallow. Add in East NE winds and upwelling rapidly cools the surface.

Bingo! 

I do remember you pointing that out. 

If you have a fast moving system...well these cooler waters won't do much for weakening b/c there isn't time. In this instance it may do a quite a bit of damage but if there is some interaction with that ulvl low and there is just enough ulvl divergence perhaps it helps to offset some of the weakening by the cooler waters. 

The wind potential still scares me a bit b/c people may see 30-40 mph and go meh but that's going to cause some issues...obviously nothing over the top crazy

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13 minutes ago, MJO812 said:

Another shift west by hurricane models

Screenshot_20210820-083434_Chrome.jpg

Every one of those that hook west involves some form of ET transition. Those are the most impactful by far. Do not slow down until after landfall. Less time over cool waters plus UL assist—stronger storm.
 

Dangerous to have another recurve so close to land and a broadly densely populated area. Forecast error highest in the vicinity of recurve. Could greatly limit lead time for accurate warnings. 

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  • dendrite changed the title to Tropical Storm Henri
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