Based on the Vortex messages from 1500Z to 2032Z, I'm inferring that Rita appears to be going over pockets of "cooler" water, and its playing havoc with the her thermodynamics. As a result she's losing entrainment, forced subsidence is weak, inner eye-wall edge boundry layer mixing is causing the humidity in the eye to increase (is already rather high), inner/outter eye temps are going down. And it seems she's struggling with EWRC. Even so, she's pretty much near full MPI.
I believe the critical point will be near 92W 27N, as whatever she has left at that point she should retain until landfall. While it appears there's a cold core high over Mexico, guidance offers no suggestion that the upper low will influence Rita in some trough-like fashion. Furthermore, the northern 2/3 of the storm is subject to shearing force approx 15 m/s. This is above the standard threshold accepted for intensification (< 10 m/s). Therefor, at this time, I'm skeptical of any significant increase in intensity from here on out.
Nevertheless, environmental conditions steadily improve from the above mentioned coordinates onwards to landfall. These environmental conditions should offset the increasingly degrading influence of approaching land (so whatever she has at those co-ordinates will be all she will be).
URNT12 KNHC 221500Z
VORTEX DATA MESSAGE
A. 22/1449Z
B. 25 DEG 18 MIN N
88 DEG 38 MIN W
C. 700 MB 2326 M
D. NA
E. NA
F. 121 DEG 135 KT
G. 35 DEG 13 NM
H. 913 MB
I. 18 C/ 3058 M
J. 22 C/ 3050 M
K. 14 C/ NA
L. OPEN SE
M. C017-55
N. 12345/7
O. 1/1 NM
P. NOAA3 1818A RITA OB 05
MAX FL WIND 135 KT NE QUAD 1446Z
URNT12 KNHC 221655Z
VORTEX DATA MESSAGE
A. 22/1619Z
B. 25 DEG 26 MIN N
88 DEG 49 MIN W
C. 700 MB 2338 M
D. 80
E. 135 DEG 15 NM
F. 211 DEG 120 KT
G. 119 DEG 11 NM
H. 915 MB
I. 12 C/ 3048 M
J. 20 C/ 3057 M
K. 16 C/ NA
L. OPEN SE
M. C018-45
N. 12345/7
O. 1/1 NM
P. NOAA3 1818A RITA OB 17
MAX FL WIND 135 KT NE QUAD 1446Z
EXCELLENT RADAR PRESENTATION, SFC CENTER OBSCURED
URNT12 KNHC 221825Z
VORTEX DATA MESSAGE
A. 22/1745Z
B. 25 DEG 34 MIN N
89 DEG 01 MIN W
C. 700 MB 2333 M
D. NA
E. NA
F. 300 DEG 120 KT
G. 200 DEG 08 NM
H. 914 MB
I. 12 C/ 3050 M
J. 21 C/ 3056 M
K. 16 C/ NA
L. OPEN SE
M. C015-50
N. 12345/7
O. 1/1 NM
P. NOAA3 1818A RITA OB 29
MAX FL WIND 125 KT NE QUAD 1754Z
URNT12 KNHC 221939
VORTEX DATA MESSAGE
A. 22/19:22:40Z
B. 25 deg 44 min N
089 deg 15 min W
C. NA mb NA m
D. NA kt
E. NA deg nm
F. 149 deg 122 kt
G. 062 deg 012 nm
H. EXTRAP 914 mb
I. 9 C/ 3658 m
J. 17 C/ 3658 m
K. 10 C/ NA
L. OPEN E
M. C16
N. 12345/NA
O. 0.02 / 1 nm
P. AF306 WX18A RITA01 OB 02
MAX FL WIND 122 KT NE QUAD 19:19:30 Z
URNT12 KNHC 221948Z
VORTEX DATA MESSAGE
A. 22/1913Z
B. 25 DEG 44 MIN N
89 DEG 13 MIN W
C. 700 MB 2329 M
D. NA
E. NA
F. 43 DEG 133 KT
G. 309 DEG 10 NM
H. 913 MB
I. 13 C/ 3059 M
J. 20 C/ 3044 M
K. 16 C/ NA
L. OPEN NE-SE
M. C018-48
N. 12345/7
O. 1/1 NM
P. NOAA3 1818A RITA OB 37
MAX FL WIND 133 KT NW QUAD 1910Z
EXCELLENT RADAR PRESENTATION
URNT12 KNHC 222032
VORTEX DATA MESSAGE
A. 22/20:20:10Z
B. 25 deg 49 min N
089 deg 22 min W
C. NA mb NA m
D. NA kt
E. NA deg nm
F. 221 deg 111 kt
G. 134 deg 010 nm
H. EXTRAP 913 mb
I. 10 C/ 3658 m
J. 16 C/ 3654 m
K. 11 C/ NA
L. CLOSED WALL
M. C17
N. 12345/NA
O. 0.02 / 1 nm
P. AF306 WX18A RITA01 OB 05
MAX FL WIND 122 KT NE QUAD 19:19:30 Z
Let's hope she's weak when she gets through 27N 92W. What do you make of the different AF/NOAA interpretations of the eyewall?
Reads like a scientific definition of a young lady getting hit on at the local bar.
000 URNT12 KNHC 222131 VORTEX DATA MESSAGE A. 22/21:20:40Z B. 25 deg 53 min N 089 deg 31 min W C. 700 mb 2337 m D. NA kt E. NA deg nm F. 324 deg 102 kt G. 222 deg 022 nm H. 913 mb I. 10 C/ 3049 m J. 18 C/ 3049 m K. 15 C/ NA L. OPEN SE M. CO16/41 N. 12345/ 7 O. 0.02 / 1 nm P. AF306 WX18A RITA01 OB 07 MAX FL WIND 122 KT NE QUAD 19:19:30 Z
"Furthermore, the northern 2/3 of the storm is subject to shearing force approx 15 m/s. This is above the standard threshold accepted for intensification (< 10 m/s). Therefor, at this time, I'm skeptical of any significant increase in intensity from here on out."
That shear you are referring to in the north half of the storm is as a result of Rita's own outflow. Since it's not environmentally-induced shear over the inner core, it doesn't affect the intensity of the storm. Strong shear on the outskirts of strong hurricanes as a result of strong outflow aloft superimposed on oppositely-directed inflow below is a defining characteristic of hurricanes. Shear that weakens hurricanes is caused by external factors, such as an upper-level trough, that disrupts the normal outflow pattern, and allows vertical shear to overspread the core.