EPAC: WILLA - Remnants

[Ntxw]

Willa is now the more impressive system of the two. Favorable wind shear for the next 5 or so days, generally up until landfall. Sufficiently warm water, a good case for another strong Cat 4.

* EAST PACIFIC 2018 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* TWENTYFOU EP242018 10/20/18 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 35 40 46 54 61 78 92 96 94 89 83 74 61
V (KT) LAND 35 40 46 54 61 78 92 96 94 89 83 74 61
V (KT) LGEM 35 39 42 46 51 63 77 90 95 91 84 73 61
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 11 9 8 7 4 4 1 6 6 5 5 10 23
SHEAR ADJ (KT) -9 -9 -7 -6 -5 -3 2 0 2 9 10 8 10
SHEAR DIR 77 99 92 115 151 99 86 137 178 155 245 217 212
SST (C) 29.3 29.3 29.3 29.3 29.2 28.8 28.9 28.6 28.2 28.0 27.7 27.6 28.4
POT. INT. (KT) 156 156 156 156 154 150 151 147 143 141 139 139 148
200 MB T (C) -53.6 -53.3 -52.9 -53.1 -53.4 -52.7 -53.2 -52.6 -52.9 -52.4 -52.6 -52.2 -52.1
200 MB VXT (C) 0.1 0.1 0.1 0.1 0.2 0.3 0.9 0.7 0.8 0.9 0.8 0.7 0.6
TH_E DEV (C) 6 6 7 7 6 7 6 7 6 7 6 7 6
700-500 MB RH 76 74 74 72 70 67 65 58 55 50 49 53 61
MODEL VTX (KT) 12 12 13 14 15 18 21 23 25 25 24 20 14
850 MB ENV VOR -14 -16 -6 -8 -17 -16 3 14 22 19 25 44 39
200 MB DIV 37 41 59 83 87 88 50 51 33 45 29 43 64
700-850 TADV -1 0 -1 -1 0 -1 -1 1 2 0 5 6 0
LAND (KM) 457 470 488 495 493 476 478 487 497 477 427 304 198
LAT (DEG N) 14.7 14.9 15.0 15.3 15.5 16.2 16.7 17.2 17.6 18.2 19.0 20.3 21.9
LONG(DEG W) 105.4 105.9 106.4 106.9 107.3 108.0 108.5 109.0 109.4 109.6 109.5 109.1 108.2
STM SPEED (KT) 7 5 5 5 5 4 3 3 3 4 6 8 9
HEAT CONTENT 29 28 27 24 23 21 18 15 13 12 14 12 20

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):265/ 9 CX,CY: -8/ 0
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 405 (MEAN=584)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 4.5 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 99.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 46.9

[cycloneye]

BULLETIN
Tropical Storm Willa Advisory Number 2
NWS National Hurricane Center Miami FL EP242018
1000 AM CDT Sat Oct 20 2018

...WILLA BECOMES THE 21ST NAMED STORM OF THE EASTERN PACIFIC
SEASON...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.8N 105.7W
ABOUT 305 MI...490 KM SSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES





Tropical Storm Willa Discussion Number 2
NWS National Hurricane Center Miami FL EP242018
1000 AM CDT Sat Oct 20 2018

A GMI microwave pass over the depression at 0916 UTC revealed that a
tight inner core has developed, with a cyan and pink ring noted in
the low-level 37-GHz channel. Outer convective banding has also
been increasing, and a consensus of the latest subjective and
objective satellite intensity estimates supports raising the maximum
winds to 35 kt and designating the cyclone as Tropical Storm Willa.
On an historical note, this is the first time that at least 21 named
storms have formed within the eastern Pacific basin since the 1992
season.

The microwave data suggest that Willa's center is a little farther
south than previously estimated, and the initial motion is
calculated to be westward, or 270/8 kt. The storm is already
located near the western periphery of a mid-level ridge which
extends across northern and central Mexico, and Willa is expected
to slowly recurve around the ridge axis during the next 4 days. By
the end of the forecast period, a mid-latitude trough located over
the western U.S. is likely to cause Willa to accelerate toward the
northeast in the direction of mainland Mexico. All of the track
models agree on this general scenario, but there are some
differences on how wide a turn Willa makes while it recurves.
There are also some speed differences that appear to be related to
how strong Willa will be when the mid-latitude trough becomes the
main steering driver. The NHC forecast is very close to the
previous forecast during the first 48 hours. After that time, the
forecast has been nudged eastward since the GFS and ECMWF models are
both near or east of the multi-model consensus aids.

With a low-level ring already observed in microwave imagery, and
Willa located in an environment of low shear and over very warm
ocean water, the cyclone appears poised to go through a period of
rapid intensification (RI). Several of the various RI indices are
over 50 percent, and thus the NHC forecast favors the high end of
the intensity guidance and explicitly shows rapid strengthening
over the next 48 hours. Willa is expected to be moving more slowly
by days 3 and 4 (about 3 kt), and upwelling of colder water could
induce some weakening by that time. An increase in shear is likely
to cause more significant weakening by the end of the forecast
period. The new NHC intensity forecast is a bit higher than the
previous forecast to account for the possibility of rapid
intensification, and it shifts Willa's expected peak intensity about
a day earlier.


FORECAST POSITIONS AND MAX WINDS

INIT 20/1500Z 14.8N 105.7W 35 KT 40 MPH
12H 21/0000Z 15.0N 106.5W 50 KT 60 MPH
24H 21/1200Z 15.3N 107.3W 65 KT 75 MPH
36H 22/0000Z 15.8N 107.9W 80 KT 90 MPH
48H 22/1200Z 16.6N 108.5W 95 KT 110 MPH
72H 23/1200Z 17.7N 109.0W 100 KT 115 MPH
96H 24/1200Z 19.0N 109.0W 90 KT 105 MPH
120H 25/1200Z 22.0N 107.5W 75 KT 85 MPH

$$
Forecaster Berg

[HurricaneRyan]

Willa wants to be bad and she will make it look so good!

[cycloneye]

Up to 45 kts.Shear will be light thru 96 hours and RI probabilities are way up.

* EAST PACIFIC 2018 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* WILLA EP242018 10/20/18 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 45 53 62 71 80 102 112 107 100 83 56 43 34
V (KT) LAND 45 53 62 71 80 102 112 107 100 83 56 43 31
V (KT) LGEM 45 53 60 68 76 93 105 106 96 80 64 58 48
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 9 7 7 5 5 2 2 3 9 8 12 26 36
SHEAR ADJ (KT) -9 -7 -5 -6 -6 -3 2 4 0 3 4 1 2
SHEAR DIR 96 94 101 130 128 358 215 215 130 203 239 226 225
SST (C) 29.3 29.2 29.2 29.1 28.9 28.4 28.6 28.3 28.1 27.8 27.7 28.9 29.0
POT. INT. (KT) 156 155 154 153 151 146 148 143 142 139 140 154 155
200 MB T (C) -53.1 -52.7 -53.0 -53.2 -52.9 -52.9 -52.3 -52.4 -52.1 -52.2 -52.4 -52.4 -52.4
200 MB VXT (C) 0.1 0.1 0.1 0.1 0.2 0.6 0.7 0.8 0.7 1.0 0.5 0.2 0.0
TH_E DEV (C) 7 7 6 6 6 6 6 6 6 6 6 6 6
700-500 MB RH 77 77 76 72 71 68 62 60 56 50 43 43 48
MODEL VTX (KT) 13 14 16 17 18 23 26 24 26 19 6 3 LOST
850 MB ENV VOR -15 -6 -11 -20 -18 -7 9 11 18 18 29 21 -5
200 MB DIV 56 73 97 92 95 102 63 58 61 63 35 18 24
700-850 TADV 0 -1 -1 0 0 0 0 2 -3 -4 4 6 3
LAND (KM) 424 440 461 463 463 438 420 406 387 343 300 222 -22
LAT (DEG N) 15.1 15.3 15.4 15.6 15.7 16.4 17.3 17.8 18.1 18.8 19.8 21.3 23.2
LONG(DEG W) 105.5 106.0 106.5 106.8 107.1 107.7 108.3 108.5 108.5 108.5 108.5 107.7 106.1
STM SPEED (KT) 5 5 4 3 4 5 4 2 2 4 7 10 12
HEAT CONTENT 28 26 24 23 22 21 15 13 14 21 20 31 35

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):295/ 5 CX,CY: -4/ 2
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 525 (MEAN=584)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 7.8 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 99.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 60.6

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 0. 0. 1. 1. 1. 1. 1. 0. -1. -1. -2. -3.
SST POTENTIAL 0. 1. 2. 3. 5. 8. 11. 14. 16. 17. 18. 17.
VERTICAL SHEAR MAG 0. 1. 2. 3. 5. 7. 8. 8. 7. 7. 4. 0.
VERTICAL SHEAR ADJ 0. 0. 0. 1. 1. 1. 0. 0. 0. 0. 0. -1.
VERTICAL SHEAR DIR 0. 1. 1. 1. 2. 1. 0. 0. 0. -1. -1. -1.
PERSISTENCE 4. 5. 6. 7. 5. 4. 3. 2. 2. 2. 2. 1.
200/250 MB TEMP. 0. 0. 0. -1. -2. -2. -2. -2. -2. -1. 0. 1.
THETA_E EXCESS 0. 0. 0. 0. 0. 0. 1. 0. 1. 0. 1. 0.
700-500 MB RH 0. 0. 1. 1. 1. 1. 1. 1. 1. 0. 0. 0.
MODEL VTX TENDENCY 0. 2. 3. 4. 9. 12. 12. 17. 8. -10. -14. -14.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 2.
200 MB DIVERGENCE 0. 1. 1. 2. 2. 3. 3. 3. 4. 4. 3. 3.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1.
ZONAL STORM MOTION 0. 0. 0. -1. -1. -1. -1. -1. -1. -1. -1. -1.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. -1. -1. -1. -2. -2. -2.
GOES PREDICTORS 1. 3. 4. 4. 4. 4. 4. 3. 2. 2. 2. 2.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
RI POTENTIAL 1. 3. 6. 11. 22. 28. 23. 11. 2. -5. -11. -15.
----------------------------------------------------------
TOTAL CHANGE 8. 17. 26. 35. 57. 67. 62. 55. 38. 11. -2. -11.

CURRENT MAX WIND (KT): 45. LAT, LON: 15.1 105.5

** 2018 E. Pacific RI INDEX EP242018 WILLA 10/20/18 18 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MORE MAXIMUM WIND INCREASE IN NEXT 24-h)

Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
POT = MPI-VMAX (KT) : 120.2 40.5 to 149.3 0.73 13.6
12 HR PERSISTENCE (KT) : 15.0 -22.0 to 44.0 0.56 12.3
850-200 MB SHEAR (KT) : 6.6 19.6 to 1.4 0.71 12.5
HEAT CONTENT (KJ/CM2) : 24.6 1.8 to 106.7 0.22 3.0
D200 (10**7s-1) : 82.6 -33.0 to 156.2 0.61 9.5
STD DEV OF IR BR TEMP : 7.8 37.8 to 2.1 0.84 10.6
MAXIMUM WIND (KT) : 45.0 22.5 to 132.0 0.65 8.1
BL DRY-AIR FLUX (W/M2) : 79.2 721.6 to -82.5 0.80 -8.6
%area of TPW <45 mm upshear : 0.0 62.3 to 0.0 1.00 1.3
2nd PC OF IR BR TEMP : -0.9 2.2 to -1.9 0.76 1.4

SHIPS Prob RI for 20kt/ 12hr RI threshold= 29% is 4.8 times climatological mean ( 6.1%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 73% is 5.8 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 64% is 7.6 times climatological mean ( 8.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 53% is 8.8 times climatological mean ( 6.0%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 38% is 9.6 times climatological mean ( 4.0%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 68% is 10.5 times climatological mean ( 6.5%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 84% is 14.3 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 52% is 10.8 times climatological mean ( 4.8%)

Matrix of RI probabilities
------------------------------------------------------------------------------
RI (kt / h) | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48 |65/72
------------------------------------------------------------------------------
SHIPS-RII: 29.1% 72.9% 63.7% 53.0% 38.4% 68.3% 84.5% 51.7%
Logistic: 40.1% 79.5% 67.6% 59.8% 66.2% 81.7% 83.1% 20.9%
Bayesian: 19.6% 64.1% 53.7% 34.3% 26.5% 47.7% 23.9% 0.4%
Consensus: 29.6% 72.1% 61.7% 49.0% 43.7% 65.9% 63.8% 24.3%
DTOPS: 44.0% 96.0% 92.0% 69.0% 68.0% 93.0% 73.0% 7.0%

## ANNULAR HURRICANE INDEX (AHI) EP242018 WILLA 10/20/18 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=3 NFAIL=4 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

CONTRIBUTIONS TO ANNULAR INDEX

[Yellow Evan]

20/1800 UTC 15.2N 105.4W T3.5/3.5 WILLA -- East Pacific

[Ntxw]

Should be a hurricane soon

[Highteeld]

Up to 45 kts.Shear will be light thru 96 hours and RI probabilities are way up.

* EAST PACIFIC 2018 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* WILLA EP242018 10/20/18 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 45 53 62 71 80 102 112 107 100 83 56 43 34
V (KT) LAND 45 53 62 71 80 102 112 107 100 83 56 43 31
V (KT) LGEM 45 53 60 68 76 93 105 106 96 80 64 58 48
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 9 7 7 5 5 2 2 3 9 8 12 26 36
SHEAR ADJ (KT) -9 -7 -5 -6 -6 -3 2 4 0 3 4 1 2
SHEAR DIR 96 94 101 130 128 358 215 215 130 203 239 226 225
SST (C) 29.3 29.2 29.2 29.1 28.9 28.4 28.6 28.3 28.1 27.8 27.7 28.9 29.0
POT. INT. (KT) 156 155 154 153 151 146 148 143 142 139 140 154 155
200 MB T (C) -53.1 -52.7 -53.0 -53.2 -52.9 -52.9 -52.3 -52.4 -52.1 -52.2 -52.4 -52.4 -52.4
200 MB VXT (C) 0.1 0.1 0.1 0.1 0.2 0.6 0.7 0.8 0.7 1.0 0.5 0.2 0.0
TH_E DEV (C) 7 7 6 6 6 6 6 6 6 6 6 6 6
700-500 MB RH 77 77 76 72 71 68 62 60 56 50 43 43 48
MODEL VTX (KT) 13 14 16 17 18 23 26 24 26 19 6 3 LOST
850 MB ENV VOR -15 -6 -11 -20 -18 -7 9 11 18 18 29 21 -5
200 MB DIV 56 73 97 92 95 102 63 58 61 63 35 18 24
700-850 TADV 0 -1 -1 0 0 0 0 2 -3 -4 4 6 3
LAND (KM) 424 440 461 463 463 438 420 406 387 343 300 222 -22
LAT (DEG N) 15.1 15.3 15.4 15.6 15.7 16.4 17.3 17.8 18.1 18.8 19.8 21.3 23.2
LONG(DEG W) 105.5 106.0 106.5 106.8 107.1 107.7 108.3 108.5 108.5 108.5 108.5 107.7 106.1
STM SPEED (KT) 5 5 4 3 4 5 4 2 2 4 7 10 12
HEAT CONTENT 28 26 24 23 22 21 15 13 14 21 20 31 35

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):295/ 5 CX,CY: -4/ 2
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 525 (MEAN=584)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 7.8 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 99.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 60.6

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 0. 0. 1. 1. 1. 1. 1. 0. -1. -1. -2. -3.
SST POTENTIAL 0. 1. 2. 3. 5. 8. 11. 14. 16. 17. 18. 17.
VERTICAL SHEAR MAG 0. 1. 2. 3. 5. 7. 8. 8. 7. 7. 4. 0.
VERTICAL SHEAR ADJ 0. 0. 0. 1. 1. 1. 0. 0. 0. 0. 0. -1.
VERTICAL SHEAR DIR 0. 1. 1. 1. 2. 1. 0. 0. 0. -1. -1. -1.
PERSISTENCE 4. 5. 6. 7. 5. 4. 3. 2. 2. 2. 2. 1.
200/250 MB TEMP. 0. 0. 0. -1. -2. -2. -2. -2. -2. -1. 0. 1.
THETA_E EXCESS 0. 0. 0. 0. 0. 0. 1. 0. 1. 0. 1. 0.
700-500 MB RH 0. 0. 1. 1. 1. 1. 1. 1. 1. 0. 0. 0.
MODEL VTX TENDENCY 0. 2. 3. 4. 9. 12. 12. 17. 8. -10. -14. -14.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 2.
200 MB DIVERGENCE 0. 1. 1. 2. 2. 3. 3. 3. 4. 4. 3. 3.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1.
ZONAL STORM MOTION 0. 0. 0. -1. -1. -1. -1. -1. -1. -1. -1. -1.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. -1. -1. -1. -2. -2. -2.
GOES PREDICTORS 1. 3. 4. 4. 4. 4. 4. 3. 2. 2. 2. 2.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
RI POTENTIAL 1. 3. 6. 11. 22. 28. 23. 11. 2. -5. -11. -15.
----------------------------------------------------------
TOTAL CHANGE 8. 17. 26. 35. 57. 67. 62. 55. 38. 11. -2. -11.

CURRENT MAX WIND (KT): 45. LAT, LON: 15.1 105.5

** 2018 E. Pacific RI INDEX EP242018 WILLA 10/20/18 18 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MORE MAXIMUM WIND INCREASE IN NEXT 24-h)

Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
POT = MPI-VMAX (KT) : 120.2 40.5 to 149.3 0.73 13.6
12 HR PERSISTENCE (KT) : 15.0 -22.0 to 44.0 0.56 12.3
850-200 MB SHEAR (KT) : 6.6 19.6 to 1.4 0.71 12.5
HEAT CONTENT (KJ/CM2) : 24.6 1.8 to 106.7 0.22 3.0
D200 (10**7s-1) : 82.6 -33.0 to 156.2 0.61 9.5
STD DEV OF IR BR TEMP : 7.8 37.8 to 2.1 0.84 10.6
MAXIMUM WIND (KT) : 45.0 22.5 to 132.0 0.65 8.1
BL DRY-AIR FLUX (W/M2) : 79.2 721.6 to -82.5 0.80 -8.6
%area of TPW <45 mm upshear : 0.0 62.3 to 0.0 1.00 1.3
2nd PC OF IR BR TEMP : -0.9 2.2 to -1.9 0.76 1.4

SHIPS Prob RI for 20kt/ 12hr RI threshold= 29% is 4.8 times climatological mean ( 6.1%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 73% is 5.8 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 64% is 7.6 times climatological mean ( 8.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 53% is 8.8 times climatological mean ( 6.0%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 38% is 9.6 times climatological mean ( 4.0%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 68% is 10.5 times climatological mean ( 6.5%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 84% is 14.3 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 52% is 10.8 times climatological mean ( 4.8%)

Matrix of RI probabilities
------------------------------------------------------------------------------
RI (kt / h) | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48 |65/72
------------------------------------------------------------------------------
SHIPS-RII: 29.1% 72.9% 63.7% 53.0% 38.4% 68.3% 84.5% 51.7%
Logistic: 40.1% 79.5% 67.6% 59.8% 66.2% 81.7% 83.1% 20.9%
Bayesian: 19.6% 64.1% 53.7% 34.3% 26.5% 47.7% 23.9% 0.4%
Consensus: 29.6% 72.1% 61.7% 49.0% 43.7% 65.9% 63.8% 24.3%
DTOPS: 44.0% 96.0% 92.0% 69.0% 68.0% 93.0% 73.0% 7.0%

## ANNULAR HURRICANE INDEX (AHI) EP242018 WILLA 10/20/18 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=3 NFAIL=4 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

CONTRIBUTIONS TO ANNULAR INDEX

Those RI thresholds make me think this will become a cat 5.

[shiny-pebble]

Starting to develop that look WPAC super typhoons and Walaka got before they bombed out.

Sent from my LG-H700 using Tapatalk

[Monsoonjr99]

Willa so far reminds me of Patricia almost exactly three years ago, not that Willa could ever get nearly as strong as Patricia, which I doubt. The type of genesis, the time of year, the likely track, SSTs, El Nino, low shear, etc. all remind me of Patricia. I'd consider Kenna and Rick analogs as well. I wonder if nearby Vicente might possibly hinder development, however.

[TorSkk]

BULLETIN
Tropical Storm Willa Advisory Number 3
NWS National Hurricane Center Miami FL EP242018
400 PM CDT Sat Oct 20 2018

...WILLA FORECAST TO RAPIDLY INTENSIFY AND BECOME A HURRICANE
OVERNIGHT...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...15.2N 105.8W
ABOUT 280 MI...450 KM SSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


Tropical Storm Willa Discussion Number 3
NWS National Hurricane Center Miami FL EP242018
400 PM CDT Sat Oct 20 2018

Willa appears to be wrapping up quickly, and the low-level center
is now embedded beneath a ragged central dense overcast. ASCAT data
from several hours ago indicated winds were as high as 40 kt, but
more recent satellite estimates support an intensity between 45-55
kt, and the maximum winds are set at 50 kt for this advisory.

Willa has turned west-northwestward and slowed down, and the
initial motion is estimated to be 295/5 kt. The cyclone is
forecast to recurve around the western edge of a mid-level ridge
that lies over Mexico during the next few days, and then accelerate
northeastward into mainland Mexico by days 4 and 5 ahead of a broad
mid-latitude trough. Compared to previous model runs, the new
track guidance has sped up significantly and also now shows a
sharper recurvature, both of which suggest that Willa's hazards
could reach the coast of Mexico sooner than originally thought.
The GFS and ECMWF remain the fastest of the models, and although
the updated NHC track forecast trends in their direction, it hangs
back a bit to give some weight to the HWRF, HCCA, and Florida State
Superensemble. Even with that consideration, the new forecast does
bring Willa to the coast sooner than before.

The satellite signature suggests that the storm is organizing
quickly and is probably in the beginning stages of rapid
intensification (RI). The RI indices are even higher this
afternoon than they were this morning, and incredibly, the HWRF,
SHIPS, HCCA, and Florida State Superensemble all bring Willa near or
at major hurricane intensity in 36 hours. The NHC forecast follows
those models' lead and indicates significant strengthening over the
next couple of days. A peak in intensity is likely to occur
between 48-72 hours, followed by some weakening due to lower
oceanic heat content and increasing vertical shear. Despite the
expected weakening, Willa is expected to reach the coast of
west-central mainland Mexico as a hurricane in about 4 days.


FORECAST POSITIONS AND MAX WINDS

INIT 20/2100Z 15.2N 105.8W 50 KT 60 MPH
12H 21/0600Z 15.5N 106.3W 65 KT 75 MPH
24H 21/1800Z 16.1N 106.9W 85 KT 100 MPH
36H 22/0600Z 16.8N 107.4W 105 KT 120 MPH
48H 22/1800Z 17.6N 107.8W 110 KT 125 MPH
72H 23/1800Z 19.1N 108.1W 100 KT 115 MPH
96H 24/1800Z 22.0N 106.5W 80 KT 90 MPH
120H 25/1800Z 24.5N 103.5W 40 KT 45 MPH...INLAND

$$
Forecaster Berg

[Yellow Evan]

Willa so far reminds me of Patricia almost exactly three years ago, not that Willa could ever get nearly as strong as Patricia, which I doubt. The type of genesis, the time of year, the likely track, SSTs, El Nino, low shear, etc. all remind me of Patricia. I'd consider Kenna and Rick analogs as well. I wonder if nearby Vicente might possibly hinder development, however.

Given how small Vicente is, highly unlikely

[Yellow Evan]

Has that look but I'd like to see some colder cloud tops.

[cycloneye]

 https://twitter.com/Cyclonebiskit/status/1053768891518791680

[Extratropical94]

00Z update, almost a hurricane:

24E WILLA 181021 0000 15.5N 105.9W EPAC 60 994

[cycloneye]

BULLETIN
Tropical Storm Willa Advisory Number 4
NWS National Hurricane Center Miami FL EP242018
900 PM MDT Sat Oct 20 2018

...WILLA ALMOST A HURRICANE...
...EXPECTED TO RAPIDLY INTENSIFY AND BECOME A MAJOR HURRICANE IN A
DAY OR SO...


SUMMARY OF 900 PM MDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...15.7N 106.1W
ABOUT 255 MI...415 KM SSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests along the coast of west-central mainland Mexico should
monitor the progress of Willa.





Tropical Storm Willa Discussion Number 4
NWS National Hurricane Center Miami FL EP242018
900 PM MDT Sat Oct 20 2018

Willa has rapidly intensified since genesis occurred last night,
and it is almost a hurricane. Geostationary satellite and
microwave images indicate that banding features have become well
established in all quadrants and the inner core has continued to
organize. There is still no evidence of an eye feature,
however. A blend of the latest satellite intensity estimates
supports increasing the initial wind speed to 60 kt.

The latest satellite fixes indicate that Willa is now moving
northwestward at about 5 kt. The storm is expected to gradually
turn to the right as it moves around the western periphery of a
mid-level ridge. In response, a northwestward motion should
continue for another day or so, followed by a turn toward the north
on Monday. After that time, a faster north-northeast to northeast
motion is expected when a shortwave trough approaches the system.
The latest model guidance, except for the UKMET, show Willa making
a sharper northward turn and at a faster pace. The NHC track
forecast has been adjusted accordingly to be in better agreement
with the latest consensus aids. This forecast is again faster than
the previous one and shows Willa making landfall over west-central
Mexico in 72 to 96 hours.

The storm has taken advantage of near ideal environmental conditions
of very low wind shear, high levels of moisture, and warm 29 deg C
SSTs. These conditions are expected to prevail for another couple
of days, and that should allow Willa to continue to strengthen
rapidly. In fact, the SHIPS Rapid Intensification (RI) indices
show about 90 percent chance of RI continuing during the next 24
hours. Based on this information and the latest model guidance, the
NHC intensity forecast shows Willa becoming a major hurricane in a
day or so. Some weakening is likely before Willa reaches the coast
due to an increase in shear and a decrease in available moisture,
but Willa is forecast to be a hurricane when it reaches the
coastline. After landfall, rapid weakening is expected due to
interaction with the rugged terrain.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0300Z 15.7N 106.1W 60 KT 70 MPH
12H 21/1200Z 16.1N 106.6W 80 KT 90 MPH
24H 22/0000Z 16.9N 107.1W 95 KT 110 MPH
36H 22/1200Z 17.7N 107.5W 110 KT 125 MPH
48H 23/0000Z 18.7N 107.8W 110 KT 125 MPH
72H 24/0000Z 20.7N 107.3W 90 KT 105 MPH
96H 25/0000Z 24.1N 104.2W 35 KT 40 MPH...INLAND
120H 26/0000Z...DISSIPATED

$$
Forecaster Cangialosi

[Ntxw]

[wxmann_91]

We had recon for other Mexico-threatening storms such as Patricia and Kenna; does anyone know why we don't have recon planned for Willa?

[Netzero9455]

Hello everyone, I'm an American living in Puerto Vallarta, I've lurked on this forum a long time marveling at the beauty of tropical cyclones worldwide, yet looking at the forecast path, and how it keeps nudging more south, I'm getting Kenna vibes from this. I was here in 2002, and although there wasn't horrific damage, there was rampant looting everywhere, power outages for about a week, and with it having to survive in horrible 90F days with dewpoints in the 75F range sans AC.

Needless to say, it is not an experience I would like to go through again, do any of you have any thoughts as of now?

I'm only worried if the storm passes slightly north of us, since due to the angle of the bay and the high mountains surrounding it, storms making landfall to the South bring nothing more than a few showers, such as was experienced during hurricane Patricia 3 years ago. If I am to expect conditions similar to or worse than with Kenna, I will definitely board up my house (more to prevent looting than anything else) and make a drive to Guadalajara with a hotel reservation for a few days.

[cycloneye]

BULLETIN
Hurricane Willa Advisory Number 5
NWS National Hurricane Center Miami FL EP242018
300 AM MDT Sun Oct 21 2018

...WILLA RAPIDLY INTENSIFIES INTO A HURRICANE SOUTHWEST OF MEXICO...
...EXPECTED TO BECOME A MAJOR HURRICANE BY MONDAY MORNING...


SUMMARY OF 300 AM MDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...16.2N 106.5W
ABOUT 240 MI...390 KM SW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests along the coasts of west-central and southwestern mainland
Mexico should monitor the progress of Willa.



Hurricane Willa Discussion Number 5
NWS National Hurricane Center Miami FL EP242018
300 AM MDT Sun Oct 21 2018

Willa has continued to rapidly intensify based on a well-defined CDO
with an intermittent pinhole eye evident in high-resolution GOES-16
infrared (IR) satellite imagery. Upper-level outflow has become well
established in all quadrants. The intensity is difficult to
ascertain since satellite intensity estimates vary widely based on
the scene type used and also the small size of the hurricane. TAFB
and SAB both provided an estimate of T4.0/65 kt, whereas UW-CIMSS
ADT and SATCON were 67 kt and 56 kt, respectively. In contrast, NHC
objective T-numbers are T5.0/90 kt using an embedded center and as
high as T6.0/115 kt using a pinhole eye. Given that the eye has not
been maintained in IR imagery, the advisory intensity of 75 kt lies
between the subjective TAFB/SAB estimate and lower NHC objective
estimate.

Willa is moving at 315/06 kt. There is no significant change to the
previous forecast track reasoning. Willa is forecast to continue
moving northwestward for the next 24 h or so, followed by a turn
toward the north on Monday, with a motion toward the northeast
expected on Tuesday as the hurricane gradually rounds the western
periphery of the deep-layer ridge. By late Tuesday, Willa is
forecast to accelerate northeastward ahead of a deep-layer trough
that will be approaching Baja California, resulting in landfall
along the west-central coast of Mexico on Wednesday. The latest 00Z
model guidance is tightly packed about the previous forecast track,
and only minor forward speed adjustments were required. A 96-h
position has been provided only for continuity purposes, and Willa
will likely have dissipated over the Mexican mountains by then.

Willa's small inner-core wind field along with ideal environmental
conditions consisting of low shear, high mid-level moisture, and
warm SSTs of 28 deg C should allow the hurricane to continue to
rapidly intensify for the next 24-36 hours, followed by a leveling
off in the intensity by early Tuesday due to expected cold upwelling
beneath the slow-moving hurricane. In 60-72 hours, increasing
southwesterly shear ahead of the aforementioned deep-layer trough is
expected to induce steady weakening until landfall occurs. Rapid
dissipation over the mountainous terrain of mainland Mexico will
occur after landfall. The official intensity forecast is a tad
above the consensus models HCCA and FSSE, and is little below the
robust Navy COAMPS-TC model forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 16.2N 106.5W 75 KT 85 MPH
12H 21/1800Z 16.8N 107.0W 85 KT 100 MPH
24H 22/0600Z 17.6N 107.4W 100 KT 115 MPH
36H 22/1800Z 18.7N 107.7W 115 KT 130 MPH
48H 23/0600Z 19.8N 107.7W 120 KT 140 MPH
72H 24/0600Z 22.3N 106.1W 90 KT 105 MPH...NEAR WNCTRL MEXICO
96H 25/0600Z 26.9N 101.2W 25 KT 30 MPH...INLAND NCNTRL MEXICO
120H 26/0600Z...DISSIPATED INLAND

$$
Forecaster Stewart

[1900hurricane]

Looking impressive on the latest F-16 pass.