Hurricane Isaias

[NorthHillsWx]

1 minute ago, cptcatz said:

I feel like asking NHC if those 100 mph winds are in the room with them right now...

FL supported 80 kts but they noted tail Doppler found slightly higher winds around them enough to justify the increase. With organization once again looking better there’s nothing to argue why further increases wouldn’t be expected tonight as well

[vortex95]

13 minutes ago, Interstate said:

I find 100MPH hard to believe with the way it looks right now.

They are reaching IMHO.  No drop in pressure and FL winds the same?  That tail radar measurement I bet was due to pulsing convection transitory spot wind, rather than true gradient.  And the Dvorak does not support 85 kt winds.  One observation does not take precedence over several observations that show the contrary.  I just find if they can hedge higher for system threading land, they will.

[vortex95]

For scale, I attached zoomed out WV image,.  The CDO/core of Isaias is very small.  That makes it much more susceptible to shear and dry air.  Also, easier RI.

The 12z HAFS A/B shows sig intensification, but the rate of weakening it shows just in the last 9 hr up to landfall is quite remarkable.  Just from a wild extreme swing one end to the other, this may be an exceptional event meteorologically.  We get lots of big RIs just before landfall (Michael, Otis), but going the other way?   I know no Atlantic situation quite like this, at least for an impending landfall.  Sure, many HUs elsewhere has got torn apart in short order, but it is so much different when close to landfall and the system is quite strong within say 12-15 hr of landfall.  A lot more eyes are on it!
 

[NorthHillsWx]

Very impressive ring of convection developing around the…. Eye…. Yes we have a legit eye now! Appears to be making another leap 

[jm1220]

Dewpoints in the upper 50s over SE TX which might as well be the Egyptian desert. If it's ramping up it has to now or very soon-because that's gonna hurt. 

[Chinook]

46 minutes ago, vortex95 said:

They are reaching IMHO.  No drop in pressure and FL winds the same?  That tail radar measurement I bet was due to pulsing convection transitory spot wind, rather than true gradient.  And the Dvorak does not support 85 kt winds.  One observation does not take precedence over several observations that show the contrary.  I just find if they can hedge higher for system threading land, they will.

Yes, I think most of the winds on the latest recon were just about 70kt, if a bit more, and then surface winds should be lower than flight level, by 10 kt. I think the continued pressure of about 978mb supports relatively the same as this morning's recon, which may have had a bit of 75-80kt flight level.

[vortex95]

4 minutes ago, Chinook said:

Yes, I think most of the winds on the latest recon were just about 70kt, if a bit more, and then surface winds should be lower than flight level, by 10 kt. I think the continued pressure of about 978mb supports relatively the same as this morning's recon, which may have had a bit of 75-80kt flight level.

FL wind reduction to sfc
700 - 90%
850 - 80%
925 - 75%
300 m - 80%
150 m mean layer - 85%

However,
Sfc-700 mb wind ratios vary from TC to TC and can range from ~70% to  >100%.  But departures from standard adjustment cannot be determined from just a few sondes b/c of convective vigor, eye wall structure/cycle, RMW, and/or low-level stability/cooler waters.

In order for 700 winds to be 100% at the sfc, I think you need an exceptional eye wall ring and the hurricane in RI mode, like Andrew was at landfall.  Also, CGs in the eye wall indicating better updraft/downdraft couplets.

[vortex95]

Another HU warm eddy RI?  Opal in Oct 1995.

80 > 130 kt in 22 hr
130 > 100 kt in 12 hr (100 at landfall).

19951003, 1200,  , HU, 22.8N,  91.6W,  80,  968, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951003, 1800,  , HU, 23.5N,  91.0W,  85,  965, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951004, 0000,  , HU, 24.5N,  90.1W, 100,  953, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951004, 0600,  , HU, 25.9N,  89.4W, 110,  935, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951004, 1000, I, HU, 26.6N,  88.8W, 130,  916, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951004, 1200,  , HU, 27.3N,  88.5W, 130,  919, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951004, 1800,  , HU, 29.0N,  87.7W, 110,  938, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
19951004, 2200, L, HU, 30.3N,  87.1W, 100,  942, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999,   50