CPAC: NORMAN - Post-Tropical

[Yellow Evan]

* EAST PACIFIC 2018 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* NORMAN EP162018 08/30/18 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 125 140 142 138 133 117 102 90 85 80 69 57 50
V (KT) LAND 125 140 142 138 133 117 102 90 85 80 69 57 50
V (KT) LGEM 125 138 140 135 127 114 104 94 84 76 68 61 56
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 8 11 17 15 16 18 21 18 15 14 14 4 4
SHEAR ADJ (KT) -1 -2 -4 -5 -3 1 0 1 4 6 4 2 -1
SHEAR DIR 68 88 102 93 67 60 53 67 107 98 111 122 183
SST (C) 29.4 29.3 29.1 28.9 28.8 28.6 28.4 28.2 28.0 27.5 26.9 26.7 26.3
POT. INT. (KT) 157 157 155 153 152 150 148 146 145 141 134 132 128
200 MB T (C) -52.5 -52.3 -52.0 -52.5 -52.3 -51.6 -51.8 -51.5 -52.0 -51.6 -52.2 -51.9 -52.2
200 MB VXT (C) 0.2 0.3 0.5 0.7 0.7 0.7 0.8 0.6 0.6 0.6 0.9 0.6 1.0
TH_E DEV (C) 6 5 6 5 5 5 6 6 5 5 5 5 5
700-500 MB RH 69 67 65 62 62 64 66 67 67 61 55 52 52
MODEL VTX (KT) 23 25 23 25 27 27 30 30 31 31 30 27 26
850 MB ENV VOR 39 49 52 52 53 78 92 103 112 106 102 97 88
200 MB DIV 55 77 42 -7 9 24 37 56 48 25 -13 11 -6
700-850 TADV -1 0 0 1 1 0 -3 -3 -3 -4 -3 2 0
LAND (KM) 952 1006 1064 1142 1221 1390 1578 1736 1843 1973 2145 1959 1695
LAT (DEG N) 17.8 17.8 17.7 17.5 17.2 16.5 15.9 15.9 16.4 17.3 18.5 19.5 20.2
LONG(DEG W) 117.6 118.4 119.2 120.0 120.8 122.3 124.1 126.0 128.0 130.5 133.4 136.1 138.6
STM SPEED (KT) 7 8 8 8 8 8 9 9 12 14 14 13 13
HEAT CONTENT 11 12 14 19 19 14 20 22 20 12 0 2 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):270/ 6 CX,CY: -5/ 0
T-12 MAX WIND: 70 PRESSURE OF STEERING LEVEL (MB): 541 (MEAN=584)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 3.7 (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): 0.0

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 -1. -2. -3. -5. -11. -20. -30. -40. -47. -53. -56. -58.
VERTICAL SHEAR MAG -2. -5. -8. -10. -14. -16. -13. -7. -2. 0. 0. -1.
VERTICAL SHEAR ADJ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1.
VERTICAL SHEAR DIR 0. 0. 1. 1. 2. 4. 5. 6. 6. 6. 5. 4.
PERSISTENCE 16. 21. 20. 17. 10. 3. -3. -8. -11. -15. -19. -19.
200/250 MB TEMP. 0. 0. 0. 0. 0. -1. 0. 0. 0. 0. 0. 0.
THETA_E EXCESS 0. 0. 0. -1. -1. -1. -1. -2. -2. -2. -3. -3.
700-500 MB RH 0. 0. 0. 0. 0. 0. 1. 1. 1. 1. 0. 0.
MODEL VTX TENDENCY 1. 0. 1. 4. 4. 7. 8. 11. 11. 9. 5. 3.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. -1. -1. -2. -3. -3. -3. -4.
200 MB DIVERGENCE 0. 0. 0. 0. 0. 0. 0. 0. 0. -1. -1. -1.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
ZONAL STORM MOTION 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1. -1.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 0. 0. -1. -1. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 1. 1. 2. 2. 2. 2.
GOES PREDICTORS 1. 2. 3. 3. 4. 4. 3. 3. 2. 2. 2. 2.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
RI POTENTIAL 0. 0. -1. -1. -2. -3. -3. -2. 0. 1. 2. 3.
----------------------------------------------------------
TOTAL CHANGE 15. 17. 13. 8. -8. -23. -35. -40. -45. -56. -68. -75.

CURRENT MAX WIND (KT): 125. LAT, LON: 17.8 117.6

** 2018 E. Pacific RI INDEX EP162018 NORMAN 08/30/18 12 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) : 29.8 40.5 to 149.3 0.00 0.0
12 HR PERSISTENCE (KT) : 55.0 -22.0 to 44.0 1.00 999.0
850-200 MB SHEAR (KT) : 13.5 19.6 to 1.4 0.33 999.0
HEAT CONTENT (KJ/CM2) : 15.0 1.8 to 106.7 0.13 999.0
D200 (10**7s-1) : 35.2 -33.0 to 156.2 0.36 999.0
STD DEV OF IR BR TEMP : 3.7 37.8 to 2.1 0.96 999.0
MAXIMUM WIND (KT) : 125.0 22.5 to 132.0 0.09 999.0
BL DRY-AIR FLUX (W/M2) : 593.6 721.6 to -82.5 0.16 999.0
%area of TPW <45 mm upshear : 0.0 62.3 to 0.0 1.00 999.0
2nd PC OF IR BR TEMP : -0.5 2.2 to -1.9 0.65 999.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 59% is 9.7 times climatological mean ( 6.1%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 22% is 1.7 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 8.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 6.0%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 4.0%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 0% is 0.0 times climatological mean ( 6.5%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 0% is 0.0 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 0% is 0.0 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: 59.1% 21.7% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Logistic: 63.9% 17.3% 18.3% 19.0% 26.7% 4.1% 2.1% 0.1%
Bayesian: 5.8% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Consensus: 43.0% 13.0% 6.1% 6.3% 8.9% 1.4% 0.7% 0.0%
DTOPS: 17.0% 2.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

## ANNULAR HURRICANE INDEX (AHI) EP162018 NORMAN 08/30/18 12 UTC ##
## PASSED SCREENING STEP, MIGHT BE ANNULAR, CALCULATE AHI FROM DISCRIMINANT ANALYSIS ##
## AHI= 1 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

CONTRIBUTIONS TO ANNULAR INDEX

[Yellow Evan]

----- Current Analysis -----
Date : 30 AUG 2018 Time : 130000 UTC
Lat : 17:46:12 N Lon : 117:41:24 W


CI# /Pressure/ Vmax
5.9 / 949.7mb/112.4kt


Final T# Adj T# Raw T#
5.9 6.2 7.0

Estimated radius of max. wind based on IR :N/A km

Center Temp : -17.7C Cloud Region Temp : -75.5C

Scene Type : EYE

[Yellow Evan]

CDO becoming much more organized.

[Ntxw]

Eye is also warming. Might be 130-135kts next advisory

[cycloneye]

Is 130 kts.

Hurricane Norman Discussion Number 10
NWS National Hurricane Center Miami FL EP162018
800 AM PDT Thu Aug 30 2018

Norman has rapidly strengthened during the past 12 to 24 hours,
with the development of a well-defined 20-nmi-wide eye and a thick
ring of cold cloud tops of -70 to -85C. Dvorak constraints have
limited the amount of increase in the subjective and objective final
T-numbers, but the most recent raw data T-numbers are between T6.5
and T7.2, which yields an initial intensity estimate of 130 kt.
Norman's intensity has increased an estimated 70 kt from 1200 UTC
yesterday morning to 1200 UTC this morning- the fastest in the
basin since Patricia in 2015. Norman has become the 5th category 4
hurricane in the eastern Pacific in 2018 and is also the strongest
hurricane in the basin so far this season.

The hurricane remains in a low-shear environment and will continue
to move over very warm waters of 29-30 degrees Celsius for another
24 hours. These conditions are expected to allow for additional
strengthening and Norman is forecast to become a category 5
hurricane later today. Eyewall replacement cycles are likely after
that time, which are difficult to predict, and should cause some
fluctuations in intensity during the next couple of days. Later in
the period, gradually decreasing sea surface temperatures and a
slight increase in shear are forecast to cause gradual weakening.
However, Norman is predicted to remain a hurricane throughout the
5-day forecast period.

Norman is moving westward or 270/7 kt. A strong subtropical ridge
that extends from the Baja California peninsula west-southwestward
into the eastern Pacific is expected to turn Norman
west-southwestward later today or tonight, with this motion
continuing over the next couple of days. The global models shift
the orientation of the ridge in a few days which should cause
Norman to turn west-northwestward by early next week. The
dynamical model guidance is tightly clustered, and the NHC track
forecast is close to the multi-model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 30/1500Z 17.8N 118.0W 130 KT 150 MPH
12H 31/0000Z 17.7N 119.1W 140 KT 160 MPH
24H 31/1200Z 17.2N 120.7W 135 KT 155 MPH
36H 01/0000Z 16.6N 122.3W 125 KT 145 MPH
48H 01/1200Z 16.1N 124.1W 120 KT 140 MPH
72H 02/1200Z 16.7N 128.0W 110 KT 125 MPH
96H 03/1200Z 18.5N 133.2W 95 KT 110 MPH
120H 04/1200Z 20.2N 138.5W 70 KT 80 MPH

$$
Forecaster Brown

[Ntxw]

Wow NHC is forecasting cat 5 by this evening. Some serious RI today.

[Yellow Evan]

Eye nearing WMG. We could see T7.0 soon.

[mrbagyo]

[storminabox]

Some truly remarkable intensification within the last 24 hours

[Cyclenall]

*Image*

I don't say this often but this is on track to reach Cat 5.

My sentiments when first looking at Norman this morning. On advisory 8 I would've forecast 140 knots for peak. What an incredible rate of EI .

It all depends on how fast that eye can clear and round out. This will determine if Norman can become a big league EI rate holder. My prediction (and this is already happening) is the typical warming cloud tops as the eye fully clears schtick will be the tale. The path where the cloud tops remain as cold during that is reserved for Patrica and Wilma type TCs.

[mrbagyo]

Let's try on another angle. Lol

[Yellow Evan]

----- Current Analysis -----
Date : 30 AUG 2018 Time : 150000 UTC
Lat : 17:45:00 N Lon : 117:56:59 W


CI# /Pressure/ Vmax
6.3 / 941.3mb/122.2kt


Final T# Adj T# Raw T#
6.3 7.0 7.0

Estimated radius of max. wind based on IR : 16 km

Center Temp : +4.5C Cloud Region Temp : -73.7C

Scene Type : EYE

[Ntxw]

*Image*

I don't say this often but this is on track to reach Cat 5.

My sentiments when first looking at Norman this morning. On advisory 8 I would've forecast 140 knots for peak. What an incredible rate of EI .

It all depends on how fast that eye can clear and round out. This will determine if Norman can become a big league EI rate holder. My prediction (and this is already happening) is the typical warming cloud tops as the eye fully clears schtick will be the tale. The path where the cloud tops remain as cold during that is reserved for Patrica and Wilma type TCs.

I don't think we will see that kind of strengthening as the two storms you are mentioning. It likely would have to sit under >30C to sustain the kind of deep, cold (CDG) convection. We've seen so far the EPAC+CPAC strengthening with decent but not extremely warm SSTs. I've seen some circles mention cold upper levels creating instability to utilize the SSTs max potential. Not well versed in this, however.

Areas that may sustain that kind of cold cloud tops might be southwest of Hawaii and perhaps later in the season southwest of Mexico.

[1900hurricane]

As far as atmosphere temperature profile is concerned, things look about the same as they do for Jebi at the other end of the Pacific. Ocean conditions actually aren't that different at the moment for the two systems either, although Jebi has the edge with higher heat content. Honestly though, both are basically T7.0 storms in the making with T7.5 potential if everything goes right.

[Cyclenall]

I don't think we will see that kind of strengthening as the two storms you are mentioning. It likely would have to sit under >30C to sustain the kind of deep, cold (CDG) convection.

That's right, only about 140 knots peak IMO. I don't know what that flattening on the east side of Norman is though.

[1900hurricane]

First warm medium grey pixel at 1600Z.

[Kingarabian]

Wow, borderline Cat.5..

[CrazyC83]

I'd go with 135 kt there. I'd want to see a bit more CMG before confidently going up to 140+.

[Ntxw]

[Yellow Evan]

I'd go with 135 kt there. I'd want to see a bit more CMG before confidently going up to 140+.

CMG isn’t a requirement for Cat 5 contrary to popular belief. A WMG eye is what Norman lacks.