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Hurricane Henri


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1 hour ago, WxWatcher007 said:

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.  

I think what I struggle with even more than a potential landfall is a particularly intense landfall considering the slow forward motion relative to climo....talk about needing the thread a needle for a land falling cane in the NE, but I guess that is always the case.

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6 minutes ago, 40/70 Benchmark said:

I think what I struggle with even more than a potential landfall is a particularly intense landfall considering the slow forward motion relative to climo....talk about needing the thread a needle for a land falling cane in the NE, but I guess that is always the case.

Quite warm SSTs. Also at the time of year when water temp is warmest. I also feel like climo favors later in the year with more of a subtropical transition. I still think a direct impact is less than 20% right now

Screenshot_20210818-094755.png

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Quite warm SSTs. Also at the time of year when water temp is warmest. I also feel like climo favors later in the year with more of a subtropical transition. I still think a direct impact is less than 20% right now
Screenshot_20210818-094755.png.bdd4ade4c3324e33e47e5f111969b8ec.png
That's an anomaly map though. Yes, SSTs off the New England and Mid-Atlantic coasts are running above climatological mean. However, that doesn't mean they're warm enough to sustain a slow moving Tropical Cyclone. There is a reason notorious New England strikes are generally associated with mid-to-upper trough interactions, phases and swift motion. They're carrying convective momentum and some baroclinic assistance while traversing that cold current. A hurricane strike for New England, even a strong one is quite possible, but we need the right setup scenario to unfold.5eb574671c5360a627b78337be6d8a55.jpg
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Not much time to post but here’s the latest discussion. Track shifted left again we will have recon going out to sample the environment. That’s huge.

Tropical Storm Henri Discussion Number  11
NWS National Hurricane Center Miami FL       AL082021
1100 AM AST Wed Aug 18 2021

Deep convection has been increasing during the past several hours in 
association with Henri, and the cloud pattern mostly consists of a 
central dense overcast with some fragmented bands around it.  The 
Dvorak estimates are steady at 3.5/55 kt from TAFB and SAB, and 
therefore, the initial intensity is held at that value.  However, 
the latest automated Dvorak values from CIMSS at the University of 
Wisconsin are higher, so it is possible that Henri could be slightly 
stronger.  An SSMIS pass from 1124 UTC showed some southward tilt 
of the vortex with height and revealed a small mid-level eye 
feature.

Henri continues to move just south of due west at 7 kt.  The storm 
is expected to move westward during the next day or so as it moves 
in the flow on the south or southeast side of a mid-level ridge.  
This ridge is expected to slide eastward by Friday as a mid- to 
upper-level low develops over the Ohio Valley and northeastern U.S. 
In response, Henri is expected to turn northward or north- 
northeastward on Friday and continue in that direction through the 
weekend.  One complicating factor is that several of the models show 
a ridge building over the northwestern Atlantic and Atlantic Canada, 
which could cause the storm to stay on a more northward track closer 
to New England than currently forecast.  The spread in the models 
for Henri's future track is quite large, with some guidance as far 
west as Long Island and as far east as 62W longitude.  Overall, the 
models continue to walk left each cycle, and the NHC track forecast 
has again been shifted in that direction.  NOAA Gulfstream IV 
missions and special weather balloon soundings have been scheduled, 
and it is hoped that this additional data will help the models 
handle the evolving steering pattern.  Given the uncertainty in the 
longer range track forecasts, users should be prepared for 
additional adjustments to the NHC track forecast in future forecast 
cycles. 

The storm is currently in an environment of about 15-20 kt of 
northerly wind shear according to the SHIPS model and analyses from 
CIMSS at the University of Wisconsin.  Since the shear is expected 
to persist or become a little stronger during the next couple of 
days, little change in strength is predicted during that time 
period.  After that time, the shear is expected to lessen and that 
should allow Henri to strengthen to a hurricane by the weekend. Some 
weakening is shown by the end of the period when Henri is forecast 
to be moving over cooler waters.  The NHC intensity forecast is 
largely an update of the previous one and is just a little lower 
than the consensus aids.

Key Messages:

1. Swells from Henri could reach much of the east coast of the U.S. 
and Atlantic Canada by the end of the week and continue through the 
weekend. These swells could cause life-threatening surf and rip 
currents.  

2. Uncertainty in the track forecast for Henri this weekend and 
early next week is larger than usual, and there is some risk of 
direct impacts from Henri in portions of the northeastern U.S. and 
Atlantic Canada during that time. Interests in these areas should 
follow updates to the forecast through the next several days.

FORECAST POSITIONS AND MAX WINDS

INIT  18/1500Z 30.0N  66.6W   55 KT  65 MPH
 12H  19/0000Z 29.9N  67.9W   60 KT  70 MPH
 24H  19/1200Z 29.8N  69.8W   60 KT  70 MPH
 36H  20/0000Z 30.1N  71.4W   60 KT  70 MPH
 48H  20/1200Z 30.7N  72.4W   60 KT  70 MPH
 60H  21/0000Z 32.1N  72.5W   65 KT  75 MPH
 72H  21/1200Z 34.2N  71.5W   75 KT  85 MPH
 96H  22/1200Z 38.0N  69.6W   75 KT  85 MPH
120H  23/1200Z 41.0N  67.0W   65 KT  75 MPH

$$
Forecaster Cangialosi

 

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1 hour ago, Windspeed said:

That's an anomaly map though. Yes, SSTs off the New England and Mid-Atlantic coasts are running above climatological mean. However, that doesn't mean they're warm enough to sustain a slow moving Tropical Cyclone. There is a reason notorious New England strikes are generally associated with mid-to-upper trough interactions, phases and swift motion. They're carrying convective momentum and some baroclinic assistance while traversing that cold current. A hurricane strike for New England, even a strong one is quite possible, but we need the right setup scenario to unfold.5eb574671c5360a627b78337be6d8a55.jpg

Good point, although you can see how even at slow speeds, it will traverse cooler water relatively quickly

Screenshot_20210818-112401.png

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12Z UKMET: Nantucket to Cape Cod most threatened

TROPICAL STORM HENRI      ANALYSED POSITION : 29.9N  66.1W

 

     ATCF IDENTIFIER : AL082021

 

                        LEAD                 CENTRAL     MAXIMUM WIND

      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)

      --------------    ----   --------   -------------  -------------

    1200UTC 18.08.2021    0  29.9N  66.1W     1004            40

    0000UTC 19.08.2021   12  29.7N  68.4W      999            51

    1200UTC 19.08.2021   24  29.5N  70.6W      987            61

    0000UTC 20.08.2021   36  29.5N  72.5W      983            63

    1200UTC 20.08.2021   48  30.0N  73.9W      981            65

    0000UTC 21.08.2021   60  31.3N  74.3W      976            68

    1200UTC 21.08.2021   72  33.7N  73.2W      961            85

    0000UTC 22.08.2021   84  37.4N  71.3W      960            81

    1200UTC 22.08.2021   96  41.1N  70.2W      962            79   near Nantucket

    0000UTC 23.08.2021  108  42.4N  69.9W   986            46  near Cape Cod

    1200UTC 23.08.2021  120  43.0N  68.0W      996            35

    0000UTC 24.08.2021  132  43.4N  65.5W     1003            27

    1200UTC 24.08.2021  144  44.2N  62.5W     1005            25

 

download.thumb.png.0380a85adb8fda289e605b197bbc522d.png

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8 minutes ago, WeatherAU said:

GEFS are like 50/50 chances NW vs. OTS.
 

GEFS are terrible for NYC Metro... Want to TRACK NW AND SUPPORT THE OPERATIONAL
I do not think it is a weak TC...

you have to define "terrible" on this board. Has dual meanings.

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As OSU pointed out, this thing is already pretty far east. Much will depend on how Henri gets through the next 24-48hr. Shear peaks in the ~36hr timeframe at around 25kt (from 16 now). That's probably not enough to decouple it completely, but depending on how convective trends end up, we could see some further southwesterly adjustments -- albeit the ensemble spread suggests not as much as we've had over the past day or two.

The airmass getting entrained via shear isn't particularly dry during max shear either, so I'm leaning stronger than I would normally.

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