Tropical Storm Chris

[miamicanes177]

Just found FL winds of 41kts...37.7mph using 80% reduction. So it looks like 40mph was a good call for that advisory.

[cybercyclone]

I don't know about strength, but Chris seems to be tracking north of the forcast points ATM.

[Brent]

I have to agree that this is not a TS at this point

Could become one again, but likely not until moving into the GOM (and chances there are less than 50/50)

This is a tropical storm according to the experts at the NHC.

But it's not according to recon. The data from them doesn't back it up.

[MississippiHurricane]

Your local met must have stayed at a Holiday Inn Express last night. That's my opinion as well, they just are being cautious and deliberate.

[miamicanes177]

But it's not according to recon. The data from them doesn't back it up.

41kts at FL...37.7mph...round up to 40mph. I believe they made the right call.

[Extremeweatherguy]

hmm..looks like Chris really is still a TS.

[dwg71]

Using 75% its 35MPH/30KTS

[StormsAhead]

What's with the 90% FL reduction? Isn't the standard reduction from 1500 ft. 70%? 1500 ft is the height of a hurricane's max winds, typically, so the reduction there is greatest.

IIRC, it's usually 70-75%, but this isn't quite your traditional hurricane. Probably a .8 or so is more appropriate (or at least so we have been using on previous missions).

The NHC is using .8 on this mission, since they are flying at 800-1000 feet. I'm not sure who is using .9

[wxman57]

What's with the 90% FL reduction? Isn't the standard reduction from 1500 ft. 70%? 1500 ft is the height of a hurricane's max winds, typically, so the reduction there is greatest.

IIRC, it's usually 70-75%, but this isn't quite your traditional hurricane. Probably a .8 or so is more appropriate (or at least so we have been using on previous missions).

Even if you use 75%, that's 29kts at the surface. But I understand that the NHC is reluctant to downgrade Chris while there are some thunderstorms over PR and the DR. They like to play it safe.

[wxman57]

What's with the 90% FL reduction? Isn't the standard reduction from 1500 ft. 70%? 1500 ft is the height of a hurricane's max winds, typically, so the reduction there is greatest.

IIRC, it's usually 70-75%, but this isn't quite your traditional hurricane. Probably a .8 or so is more appropriate (or at least so we have been using on previous missions).

The NHC is using .8 on this mission, since they are flying at 800-1000 feet. I'm not sure who is using .9

A .8 reduciton yields 31 kts, not 34 kts.

[WindRunner]

And 43kts now . . . VDM shortly.

[miamicanes177]

wow now 43kts. Yep 40mph for sure.

[Extremeweatherguy]

What's with the 90% FL reduction? Isn't the standard reduction from 1500 ft. 70%? 1500 ft is the height of a hurricane's max winds, typically, so the reduction there is greatest.

IIRC, it's usually 70-75%, but this isn't quite your traditional hurricane. Probably a .8 or so is more appropriate (or at least so we have been using on previous missions).

Even if you use 75%, that's 29kts at the surface. But I understand that the NHC is reluctant to downgrade Chris while there are some thunderstorms over PR and the DR. They like to play it safe.

75% of the newly found 43 kt. FL winds would be roughly 32 knots at the surface. And 80% would be roughly 34-35 kts.

[StormsAhead]

What's with the 90% FL reduction? Isn't the standard reduction from 1500 ft. 70%? 1500 ft is the height of a hurricane's max winds, typically, so the reduction there is greatest.

IIRC, it's usually 70-75%, but this isn't quite your traditional hurricane. Probably a .8 or so is more appropriate (or at least so we have been using on previous missions).

The NHC is using .8 on this mission, since they are flying at 800-1000 feet. I'm not sure who is using .9

A .8 reduciton yields 31 kts, not 34 kts.

Right, and they said that they kept Chris a TS despite the TD winds because they thought there were some higher winds "somewhere in the storm".

[StormsAhead]

986
SXXX50 KNHC 032150
AF308 0603A CHRIS HDOB 33 KNHC
2139 2100N 06744W 00338 0015 143 040 216 216 042 00365 0000000000
2139. 2059N 06745W 00336 0014 143 040 216 216 041 00362 0000000000
2140 2058N 06746W 00338 0014 145 039 218 218 040 00363 0000000000
2140. 2057N 06747W 00339 0013 146 040 218 218 041 00363 0000000000
2141 2056N 06748W 00336 0011 144 041 220 220 042 00359 0000000000
2141. 2055N 06749W 00337 0010 142 043 220 220 043 00359 0000000000
2142 2054N 06751W 00338 0009 142 042 220 220 042 00359 0000000000
2142. 2054N 06752W 00335 0007 144 043 220 220 043 00354 0000000000
2143 2053N 06753W 00337 0005 142 042 222 222 042 00354 0000000000
2143. 2052N 06755W 00337 0003 141 040 228 228 041 00352 0000000000
2144 2051N 06756W 00338 0002 143 033 230 230 037 00351 0000000000
2144. 2050N 06758W 00339 5000 138 024 232 232 029 00350 0000000000
2145 2049N 06759W 00336 5000 135 018 240 240 019 00347 0000000000
2145. 2048N 06800W 00337 5001 138 015 244 244 017 00348 0000000000
2146 2047N 06801W 00338 5001 132 013 240 240 014 00348 0000000000
2146. 2046N 06803W 00338 5001 131 011 240 240 012 00348 0000000000
2147 2045N 06804W 00337 5002 135 010 240 240 011 00346 0000000000
2147. 2044N 06805W 00337 5002 136 009 240 240 009 00347 0000000000
2148 2042N 06806W 00337 5001 132 008 240 240 009 00347 0000000000
2148. 2041N 06807W 00338 5000 134 005 240 240 006 00349 0000000000

[JonathanBelles]

whats the correct reduction for this? is there a table for reductions?

[StormsAhead]

And they ended up being right, 43 knots just reported, which is equivalent to 34.4 knots.

[WindRunner]

And now we have 43*.8=34.4, so the NHC will feel good about their 5pm advisory being correct.

[Regit]

I think it's .8.

So winds are now about 39.6 MPH.

[Extremeweatherguy]

I wonder if these higher winds are due to the convection firing SE of the center right now?