EPAC: BONNIE - Post-Tropical - Discussion

[Yellow Evan]

Core seems somewhat unstable making it more vulnerable to dry air intrusions than I’d expect. About 18-24 hours left to try to intensify further but somewhat less likely to become a major on second peak than I previously thought.

[Sciencerocks]

[cycloneye]

EP, 04, 2022070700, , BEST, 0, 167N, 1107W, 85, 977, HU

[Sciencerocks]

[Sciencerocks]

130
WTPZ44 KNHC 070237
TCDEP4

Hurricane Bonnie Discussion Number 38
NWS National Hurricane Center Miami FL EP042022
900 PM MDT Wed Jul 06 2022

Over the past several hours, Bonnie appears to have succumbed to
the effects of northwesterly wind shear. Satellite infrared
imagery shows no distinguishable eye feature and cold cloud tops of
-80C or less are only present in southeastern quadrant of the storm.
The initial intensity has been lowered to 85 kt because of the
recent reduction of inner core convective organization. This is
between the final T and Current Intensity numbers from TAFB and SAB.

Water vapor satellite imagery shows a dry air mass ahead of Bonnie.
This atmospheric environment, and decreasing sea surface
temperatures, are expected to continue weakening the storm
gradually. Within about a day, the tropical cyclone should cross
into ocean temperatures of less than 26 C which will likely quicken
the rate of weakening. Bonnie is forecast to become post-tropical
by 60 hours, but simulated satellite infrared imagery from the GFS
and ECMWF suggest this transition could occur even sooner. The
official intensity forecast is close to the previous advisory and
lies on the lower end of the intensity guidance.

The hurricane continues to move to the west-northwest at about 12
kt on the periphery of a mid-level ridge to its north. This
synoptic feature is predicted to steer Bonnie west-northwestward
for the next couple of days until its circulation weakens and the
shallower vortex follows the faster, westward trade wind flow. The
updated NHC track forecast is slightly north of the one from
the previous advisory and closely follows the consensus model
guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 07/0300Z 16.9N 111.3W 85 KT 100 MPH
12H 07/1200Z 17.4N 113.2W 80 KT 90 MPH
24H 08/0000Z 18.1N 116.0W 70 KT 80 MPH
36H 08/1200Z 18.7N 119.3W 60 KT 70 MPH
48H 09/0000Z 19.3N 122.8W 50 KT 60 MPH
60H 09/1200Z 19.7N 126.4W 35 KT 40 MPH...POST-TROPICAL
72H 10/0000Z 20.0N 130.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 11/0000Z 20.2N 136.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 12/0000Z...DISSIPATED

$$
Forecaster Bucci/Pasch

[Yellow Evan]

Should try again soon though it only has about eight or so hours left.

[Yellow Evan]

TXPZ25 KNES 071218
TCSENP

A. 02L (BONNIE)

B. 07/1130Z

C. 17.1N

D. 112.8W

E. THREE/GOES-W

F. T3.5/4.0

G. IR/EIR/SWIR/AMSR2

H. REMARKS...CENTER REPOSITIONED BASED ON 0844Z AMSR2 THAT SHOWED THE
CENTER FARTHER SOUTH. CENTER IS EMBEDDED IN LG RESULTING IN A DT OF
4.5. MET IS 3.0 AND PT IS 3.5. FT IS BASED ON PT DUE TO UNCERTAINTY IN
THE CENTER LOCATION.

I. ADDL POSITIONS

07/0844Z 16.9N 112.3W AMSR2


...GATLING

Worst Dvorak fix by SAB in a while.

[cycloneye]

EP, 04, 2022070712, , BEST, 0, 172N, 1131W, 80, 980, HU,

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2021 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* BONNIE EP042022 07/07/22 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
V (KT) NO LAND 80 78 74 72 67 60 50 42 33 31 29 29 29 29 29 27 24
V (KT) LAND 80 78 74 72 67 60 50 42 33 31 29 29 29 29 29 27 24
V (KT) LGEM 80 76 71 65 60 51 43 37 33 N/A N/A N/A N/A N/A N/A N/A N/A
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP N/A N/A N/A N/A N/A N/A N/A N/A

SHEAR (KT) 9 5 4 1 5 2 3 7 15 N/A N/A N/A N/A N/A N/A N/A N/A
SHEAR ADJ (KT) 5 7 5 8 6 2 2 0 0 N/A N/A N/A N/A N/A N/A N/A N/A
SHEAR DIR 300 262 205 211 333 110 265 237 260 N/A N/A N/A N/A N/A N/A N/A N/A
SST (C) 26.7 26.6 25.6 25.5 25.2 24.2 22.8 22.8 22.5 N/A N/A N/A N/A N/A N/A N/A N/A
POT. INT. (KT) 132 131 121 121 117 107 93 92 89 N/A N/A N/A N/A N/A N/A N/A N/A
200 MB T (C) -52.2 -52.1 -51.9 -52.1 -52.3 -52.3 -52.6 -52.8 -53.3 N/A N/A N/A N/A N/A N/A N/A N/A
200 MB VXT (C) 0.8 0.8 0.8 1.0 1.1 0.8 0.8 0.7 0.7 N/A N/A N/A N/A N/A N/A N/A N/A
TH_E DEV (C) 4 3 2 2 1 1 1 1 1 N/A N/A N/A N/A N/A N/A N/A N/A
700-500 MB RH 59 56 55 51 49 42 40 34 32 N/A N/A N/A N/A N/A N/A N/A N/A
MODEL VTX (KT) 18 18 16 17 15 14 12 10 9 LOST LOST LOST LOST LOST LOST LOST LOST
850 MB ENV VOR 34 34 29 37 26 21 31 35 18 N/A N/A N/A N/A N/A N/A N/A N/A
200 MB DIV 3 21 27 8 0 1 -3 7 -15 N/A N/A N/A N/A N/A N/A N/A N/A
700-850 TADV 2 4 4 1 0 8 1 2 3 N/A N/A N/A N/A N/A N/A N/A N/A
LAND (KM) 711 750 813 903 998 1235 1468 1783 2055 N/A N/A N/A N/A N/A N/A N/A N/A
LAT (DEG N) 17.2 17.6 18.0 18.3 18.6 19.2 19.7 19.8 20.1 N/A N/A N/A N/A N/A N/A N/A N/A
LONG(DEG W) 113.1 114.5 115.8 117.6 119.3 122.7 126.4 130.2 133.4 N/A N/A N/A N/A N/A N/A N/A N/A
STM SPEED (KT) 13 13 15 17 16 17 17 16 15 N/A N/A N/A N/A N/A N/A N/A N/A
HEAT CONTENT 2 2 0 0 0 0 0 0 0 N/A N/A N/A N/A N/A N/A N/A N/A

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):285/ 12 CX,CY: -11/ 3
T-12 MAX WIND: 85 PRESSURE OF STEERING LEVEL (MB): 552 (MEAN=587)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 8.4 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 91.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 2.7

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
------------------------------------------------------------------------------
SAMPLE MEAN CHANGE 0. 0. 1. 1. 1. 2. 1. 1. 0. -0. -1. -2. -2. -3. -4. -4.
SST POTENTIAL -0. -1. -1. -3. -7. -13. -19. -25. -28. -31. -34. -37. -40. -42. -45. -48.
VERTICAL SHEAR MAG -0. -0. 1. 1. 3. 6. 7. 7. 8. 9. 10. 10. 10. 10. 10. 11.
VERTICAL SHEAR ADJ -0. -1. -2. -2. -3. -3. -2. -1. -1. -0. -0. -0. -0. -0. -1. -1.
VERTICAL SHEAR DIR -0. -1. -1. -1. -2. -3. -3. -3. -4. -4. -4. -4. -4. -3. -3. -3.
PERSISTENCE -1. -2. -2. -2. -2. -1. -1. -0. -0. -0. 0. 0. 0. 0. 0. 0.
200/250 MB TEMP. -0. -0. -0. -0. -0. 0. 1. 2. 3. 4. 5. 5. 6. 8. 9. 10.
THETA_E EXCESS -0. -1. -2. -2. -5. -6. -8. -9. -10. -11. -12. -12. -13. -13. -15. -17.
700-500 MB RH -0. -0. -0. -0. -1. -1. -1. -2. -2. -2. -2. -2. -3. -3. -4. -6.
MODEL VTX TENDENCY -0. -1. -1. -2. -2. -5. -10. -13. -13. -13. -12. -11. -10. -9. -8. -8.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. -0. -0. -0. -0. -0. 0. 0. 0. 0. 0. 0.
200 MB DIVERGENCE -0. -0. -0. -1. -1. -1. -2. -3. -4. -4. -4. -3. -2. -1. 0. 1.
850-700 T ADVEC -0. -0. -0. -0. -0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 2.
ZONAL STORM MOTION 0. 0. 0. 1. 1. 2. 2. 2. 1. 1. 1. 1. 1. 1. 0. -0.
STEERING LEVEL PRES -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -1. -1. -0. -0. -0. -0.
DAYS FROM CLIM. PEAK -0. -0. -0. -0. -0. -0. -0. -1. -1. -2. -2. -2. -2. -3. -3. -4.
GOES PREDICTORS 1. 1. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2. 2. 2. 1. 1.
OCEAN HEAT CONTENT -0. -0. -0. -0. -0. -1. -2. -1. -1. -0. 0. 1. 2. 3. 4. 6.
RI POTENTIAL -0. -1. -1. -2. -3. -4. -2. -1. 1. 2. 3. 4. 4. 4. 4. 4.
------------------------------------------------------------------------------
TOTAL CHANGE -2. -6. -8. -13. -20. -30. -38. -47. -49. -51. -51. -51. -51. -51. -53. -56.

CURRENT MAX WIND (KT): 80. LAT, LON: 17.2 113.1

** 2021 E. Pacific RI INDEX EP042022 BONNIE 07/07/22 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) : 44.5 40.5 to 149.3 0.04 999.0
12 HR PERSISTENCE (KT) : -5.0 -22.0 to 44.0 0.26 999.0
D200 (10**7s-1) : 11.8 -33.0 to 159.5 0.23 999.0
850-200 MB SHEAR (KT) : 4.8 19.6 to 1.3 0.81 999.0
MAXIMUM WIND (KT) : 80.0 22.5 to 132.0 0.70 999.0
STD DEV OF IR BR TEMP : 8.4 37.8 to 2.1 0.82 999.0
BL DRY-AIR FLUX (W/M2) : 528.0 800.8 to -82.5 0.31 999.0
HEAT CONTENT (KJ/CM2) : 0.8 2.7 to 106.7 0.00 0.0
%area of TPW <45 mm upshear : 26.9 56.6 to 0.0 0.52 999.0
2nd PC OF IR BR TEMP : 0.4 2.2 to -2.3 0.41 999.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 10% is 1.6 times climatological mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 17% is 1.3 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 8.6%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 6.2%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 4.2%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 0% is 0.0 times climatological mean ( 6.7%)
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 ( 4.7%)

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: 10.0% 16.6% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Logistic: 1.8% 1.8% 4.4% 0.3% 0.4% 0.0% 0.0% 0.0%
Bayesian: 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Consensus: 3.9% 6.1% 1.5% 0.1% 0.1% 0.0% 0.0% 0.0%
DTOPS: 999.0% 999.0% 999.0% 999.0% 999.0% 999.0% 999.0% 999.0%

## ANNULAR HURRICANE INDEX (AHI) EP042022 BONNIE 07/07/22 12 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

[Sciencerocks]

[cheezyWXguy]

They keep lowering the assumed intensity but the structure actually seems to be improving. Bonnie is persistent

[Yellow Evan]

T5.5 instantaneous DT. Probably a Category 2 again in reality.

[Yellow Evan]

TXPZ25 KNES 071807
TCSENP

A. 02L (BONNIE)

B. 07/1731Z

C. 17.6N

D. 114.4W

E. THREE/GOES-W

F. T4.0/4.0

G. IR/EIR/VIS

H. REMARKS...IN EIR DG EYE EMBEDDED IN LG GIVES DT=5.0 WITH NO EYE
ADJUSTMENT. HOWEVER, BANDING EYE AVERAGING 3/4 DEGREE IN VIS GIVES DT=3.5
AFTER SUBTRACTING 1/2 FOR POORLY DEFINED EYE. ALSO, 8/10 BANDING GIVES
DT=3.5. MET IS 4.5 BASED ON SLOW WEAKENING. PT IS 4.0. FT IS BASED ON
PT DUE TO CONFLICTING SIGNALS REGARDING INTENSITY.

I. ADDL POSITIONS

NIL


...GATLING

Why is SAB busting out a banding eye scene lol?

[cycloneye]

EP, 04, 2022070718, , BEST, 0, 175N, 1145W, 80, 980, HU

[Yellow Evan]

[skyline385]

Looking pretty good right now

[Yellow Evan]

[Ntxw]

If you didn't know any better, looking at satellite you'd think she's a major again.

[weeniepatrol]

What a fighter!

[weeniepatrol]