EPAC: HERNAN - Remnants

[Nancy Smar]

EP, 97, 2020082306, , BEST, 0, 155N, 1075W, 20, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1010, 120, 90, 0, 0, E, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 024, SPAWNINVEST, ep762020 to ep972020, SPAWNINVEST, ep762020 to ep962020, SPAWNINVEST, ep762020 to ep962020, SPAWNINVEST, ep762020 to ep962020,

[cycloneye]

Nancy Smar, finnally is 97E. That best track was not the right one with 96E.

EP, 97, 2020082312, , BEST, 0, 154N, 1074W, 20, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1009, 150, 90, 0, 0, E, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 024,

[Yellow Evan]

An elongated area of low pressure located several hundred miles
south of the southern tip of the Baja California peninsula
continues to produce a large area of disorganized cloudiness and
thunderstorms. Conditions appear favorable for development, and a
tropical depression is expected to form during the next couple of
days while the system meanders or drifts northward a few hundred
miles offshore the coast of southwestern Mexico.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2020 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* INVEST EP972020 08/23/20 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
V (KT) NO LAND 30 35 40 45 51 59 68 73 78 74 71 67 64 59 56 52 50
V (KT) LAND 30 35 40 45 51 59 68 73 78 74 71 67 64 59 56 52 50
V (KT) LGEM 30 33 35 37 40 44 50 56 60 60 57 53 47 40 35 30 26
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 10 10 16 18 15 16 14 13 14 22 24 20 16 14 16 17 14
SHEAR ADJ (KT) 1 3 6 3 -1 -1 -2 0 4 6 4 3 7 2 6 0 3
SHEAR DIR 28 20 32 45 63 69 54 76 105 120 117 117 114 112 116 121 109
SST (C) 28.5 28.5 28.5 28.6 28.7 29.0 29.2 29.0 29.1 28.6 28.5 27.4 27.7 26.4 25.7 25.8 25.6
POT. INT. (KT) 147 146 146 147 148 152 154 152 154 149 149 138 142 128 120 120 117
200 MB T (C) -52.4 -51.8 -52.3 -52.6 -52.4 -52.3 -52.0 -51.7 -51.6 -51.3 -51.0 -50.9 -51.0 -50.9 -51.0 -51.0 -51.4
200 MB VXT (C) 0.3 0.2 0.3 0.3 0.3 0.4 0.1 0.2 0.2 0.5 0.7 0.8 0.5 0.7 0.6 0.4 0.2
TH_E DEV (C) 5 5 5 6 6 6 6 6 6 6 5 4 2 1 1 1 1
700-500 MB RH 67 68 68 68 69 69 68 73 78 79 74 68 63 61 57 57 53
MODEL VTX (KT) 10 12 12 14 15 16 20 21 23 22 23 21 21 19 18 16 14
850 MB ENV VOR 42 39 35 39 58 57 72 60 78 98 110 97 68 52 57 65 69
200 MB DIV 126 137 107 104 99 94 65 63 60 61 33 23 -3 12 17 3 -6
700-850 TADV -2 -5 -12 -11 -7 -12 -11 -7 0 4 9 2 3 6 5 3 0
LAND (KM) 808 841 851 839 818 759 688 602 513 413 403 498 621 826 1017 1184 1316
LAT (DEG N) 14.6 14.6 14.7 15.0 15.3 15.8 16.5 17.3 18.3 19.3 20.2 20.9 21.5 xx.x xx.x xx.x xx.x
LONG(DEG W) 110.7 111.1 111.3 111.4 111.4 111.1 110.8 110.4 110.4 111.0 112.6 114.7 117.2 xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 5 3 2 3 3 3 4 5 5 7 10 11 12 12 10 8 5
HEAT CONTENT 11 11 11 12 13 14 16 16 17 14 10 3 5 1 0 0 0

FORECAST TRACK FROM TABM INITIAL HEADING/SPEED (DEG/KT):250/ 6 CX,CY: -5/ -1
T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 489 (MEAN=587)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 7.7 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 93.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 34.5

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. -3. -4. -4. -5.
SST POTENTIAL 0. 1. 1. 2. 6. 11. 17. 22. 25. 28. 30. 31. 32. 32. 32. 32.
VERTICAL SHEAR MAG 1. 1. 2. 2. 2. 1. -0. -2. -5. -8. -10. -10. -9. -10. -11. -12.
VERTICAL SHEAR ADJ -0. -1. -1. -1. -0. 0. 0. -0. -0. -0. 0. 0. 0. 0. -0. -0.
VERTICAL SHEAR DIR 0. 1. 1. 2. 3. 4. 5. 5. 5. 4. 3. 2. 1. 1. 0. -0.
PERSISTENCE 1. 1. 1. 2. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1.
200/250 MB TEMP. -0. -0. -0. -1. -1. -1. -2. -2. -2. -2. -1. -1. 0. 1. 2. 2.
THETA_E EXCESS -0. -0. -0. -1. -1. -1. -1. -1. -1. -1. -2. -2. -3. -4. -5. -7.
700-500 MB RH 0. 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 2.
MODEL VTX TENDENCY 1. 1. 3. 4. 5. 10. 13. 18. 16. 17. 15. 13. 9. 8. 5. 3.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. -0. -0. -1. -1. -1. -1. -1. -2. -1. -1. -1.
200 MB DIVERGENCE 0. 1. 1. 1. 2. 2. 4. 4. 5. 4. 4. 3. 2. 1. 0. 0.
850-700 T ADVEC 0. 0. 0. 0. 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. -1. -1. -0. 0.
STEERING LEVEL PRES -0. -0. -1. -1. -1. -1. -1. -1. -2. -2. -2. -2. -1. -1. -1. -0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 1. 1. 1. 2. 3. 3. 3. 4. 4. 5. 5.
GOES PREDICTORS 1. 3. 3. 3. 3. 2. 2. 2. 1. 1. 1. 2. 1. 1. 1. -0.
OCEAN HEAT CONTENT 0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. 0. 0. 1. 2. 3.
RI POTENTIAL 1. 2. 4. 5. 8. 7. 4. 1. -1. -2. -3. -4. -4. -4. -4. -4.
------------------------------------------------------------------------------
TOTAL CHANGE 5. 10. 15. 21. 29. 38. 43. 48. 44. 41. 37. 34. 29. 26. 22. 20.

CURRENT MAX WIND (KT): 30. LAT, LON: 14.6 110.7

** 2020 E. Pacific RI INDEX EP972020 INVEST 08/23/20 18 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MOREMAXIMUM WIND INCREASE IN NEXT 24-h)

Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
POT = MPI-VMAX (KT) : 116.8 40.5 to 149.3 0.70 6.9
12 HR PERSISTENCE (KT) : 5.0 -22.0 to 44.0 0.41 4.8
850-200 MB SHEAR (KT) : 13.9 19.6 to 1.4 0.31 2.8
D200 (10**7s-1) : 114.6 -33.0 to 160.6 0.76 7.1
MAXIMUM WIND (KT) : 30.0 22.5 to 132.0 0.21 1.5
STD DEV OF IR BR TEMP : 7.7 37.8 to 2.1 0.84 4.9
HEAT CONTENT (KJ/CM2) : 11.6 2.7 to 106.7 0.09 0.5
BL DRY-AIR FLUX (W/M2) : 94.0 800.8 to -82.5 0.80 -5.8
%area of TPW <45 mm upshear : 0.0 56.6 to 0.0 1.00 2.4
2nd PC OF IR BR TEMP : -1.0 2.2 to -1.9 0.77 0.5

SHIPS Prob RI for 20kt/ 12hr RI threshold= 14% is 2.3 times climatological mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 31% is 2.5 times climatological mean (12.6%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 26% is 3.0 times climatological mean ( 8.6%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 17% is 2.8 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= 22% is 3.3 times climatological mean ( 6.7%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 22% is 3.7 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 27% is 5.8 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: 14.3% 31.0% 25.6% 17.4% 0.0% 21.8% 22.1% 27.4%
Logistic: 11.7% 37.8% 21.6% 15.6% 3.6% 22.7% 22.5% 12.4%
Bayesian: 1.7% 4.7% 2.1% 0.5% 0.0% 0.4% 0.3% 1.6%
Consensus: 9.3% 24.5% 16.4% 11.2% 1.2% 15.0% 15.0% 13.8%
DTOPS: 999.0% 999.0% 999.0% 999.0% 999.0% 999.0% 999.0% 999.0%

## ANNULAR HURRICANE INDEX (AHI) EP972020 INVEST 08/23/20 18 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) ##

[cycloneye]

A broad area of low pressure located several hundred miles south of
the southern tip of the Baja California peninsula continues to
produce a large area of cloudiness and thunderstorms. Conditions
appear favorable for development, and a tropical depression is
expected to form during the next couple of days while the system
meanders or drifts northward a few hundred miles offshore of the
coast of southwestern Mexico.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

[Yellow Evan]

An elongated zone of disturbed weather is located several hundred
miles south-southwest of the southern tip of the Baja California
peninsula. This weather is expected to consolidate in a couple of
days, and environmental conditions appear conducive for a tropical
depression to form later this week while the system meanders or
drifts northward a few hundred miles offshore of the coast of
southwestern Mexico.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

[Yellow Evan]

24/1730 UTC 15.1N 108.3W T1.5/1.5 97E -- East Pacific

[Yellow Evan]

An elongated zone of disturbed weather is located several hundred
miles south-southwest of the southern tip of the Baja California
peninsula. Environmental conditions appear conducive for a
tropical depression to form later this week while the system
meanders or drifts northward a few hundred miles offshore of the
coast of southwestern Mexico.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

[Yellow Evan]

A low pressure system located a few hundred miles south-southeast of
the southern tip of the Baja California peninsula continues to show
signs of organization. This system will likely become a tropical
depression or tropical storm during the next day or two while it
moves slowly east-northeastward or northeastward, near or just west
of the southwestern coast of Mexico. For more information on this
system, see High Seas forecasts issued by the National Weather
Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

[Yellow Evan]

25/2330 UTC 16.5N 107.7W T2.0/2.5 97E -- East Pacific

[Yellow Evan]

Satellite images indicate that showers and thunderstorms have become
better organized in association with a low pressure system located
about 250 miles west-southwest of the southwestern coast of Mexico.
If this development trend continues, advisories could be initiated
on this system early Wednesday. This disturbance is expected to
move slowly northeastward near or just west of the southwestern
coast of Mexico during the next few days. For more information on
this system, see High Seas forecasts issued by the National Weather
Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

[Yellow Evan]

26/0530 UTC 17.0N 106.8W T2.0/2.5 97E -- East Pacifi

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2020 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* THIRTEEN EP132020 08/26/20 06 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
V (KT) NO LAND 30 30 31 30 29 28 26 26 29 30 30 30 31 31 33 35 38
V (KT) LAND 30 30 31 30 29 28 26 26 29 30 30 30 31 31 33 35 38
V (KT) LGEM 30 29 28 27 25 22 21 19 18 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) 23 27 25 24 25 17 19 17 11 N/A N/A N/A N/A N/A N/A N/A N/A
SHEAR ADJ (KT) 5 6 5 4 4 5 4 0 1 N/A N/A N/A N/A N/A N/A N/A N/A
SHEAR DIR 74 80 77 71 70 89 84 93 99 N/A N/A N/A N/A N/A N/A N/A N/A
SST (C) 28.4 28.6 29.0 29.1 29.3 27.9 27.3 26.7 26.1 N/A N/A N/A N/A N/A N/A N/A N/A
POT. INT. (KT) 146 148 152 154 156 142 136 129 123 N/A N/A N/A N/A N/A N/A N/A N/A
200 MB T (C) -51.6 -51.7 -51.4 -51.0 -51.2 -50.6 -50.6 -50.4 -50.3 N/A N/A N/A N/A N/A N/A N/A N/A
200 MB VXT (C) 0.2 0.4 0.4 0.3 0.4 0.5 0.4 0.2 0.0 N/A N/A N/A N/A N/A N/A N/A N/A
TH_E DEV (C) 6 6 7 8 6 7 7 7 5 N/A N/A N/A N/A N/A N/A N/A N/A
700-500 MB RH 74 77 79 79 79 77 74 71 71 N/A N/A N/A N/A N/A N/A N/A N/A
MODEL VTX (KT) 13 15 16 14 12 13 10 11 LOST LOST LOST LOST LOST LOST LOST LOST LOST
850 MB ENV VOR 25 25 27 22 26 42 79 71 76 N/A N/A N/A N/A N/A N/A N/A N/A
200 MB DIV 108 85 70 71 53 43 75 64 54 N/A N/A N/A N/A N/A N/A N/A N/A
700-850 TADV -5 -2 -4 -5 -6 -6 -5 -6 -11 N/A N/A N/A N/A N/A N/A N/A N/A
LAND (KM) 299 245 191 169 151 191 244 103 26 N/A N/A N/A N/A N/A N/A N/A N/A
LAT (DEG N) 17.3 xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x
LONG(DEG W) 106.8 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 5 5 5 5 6 7 7 7 7 N/A N/A N/A N/A N/A N/A N/A N/A
HEAT CONTENT 14 17 21 25 29 15 11 2 0 N/A N/A N/A N/A N/A N/A N/A N/A

FORECAST TRACK FROM OFPI INITIAL HEADING/SPEED (DEG/KT): 35/ 5 CX,CY: 3/ 4
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 691 (MEAN=587)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 12.5 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 13.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 0.4

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. -3. -4. -4. -5.
SST POTENTIAL 0. 0. 1. 2. 6. 11. 16. 20. 23. 26. 27. 28. 29. 30. 31. 32.
VERTICAL SHEAR MAG 1. 1. 1. 2. 1. -1. -5. -8. -12. -15. -16. -17. -17. -17. -19. -20.
VERTICAL SHEAR ADJ -0. -1. -1. -2. -2. -3. -2. -1. -1. -0. 0. 0. 0. 0. -0. -1.
VERTICAL SHEAR DIR 0. 0. 1. 1. 1. -0. -1. -2. -2. -3. -3. -3. -2. -2. -2. -2.
PERSISTENCE -0. -0. -0. -1. -1. -1. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0.
200/250 MB TEMP. -0. -0. -1. -1. -1. -2. -1. -2. -2. -2. -3. -2. -2. -2. -1. -0.
THETA_E EXCESS -0. -0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 0.
700-500 MB RH 0. 0. 0. 1. 1. 1. 1. 1. 1. 1. 2. 2. 2. 2. 3. 4.
MODEL VTX TENDENCY 1. 1. 0. -1. -1. -3. -3. -3. -3. -3. -3. -2. -2. -2. -2. -2.
850 MB ENV VORTICITY -0. -0. -0. -0. 0. -0. -0. -0. -1. -1. -1. -1. -1. -1. -1. -0.
200 MB DIVERGENCE 0. 0. 1. 1. 1. 1. 2. 2. 3. 3. 3. 3. 2. 1. 1. 0.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. -0. 0. -0. -0. -0. -0. -1. -1. -1. -2.
ZONAL STORM MOTION -0. -1. -1. -2. -3. -4. -4. -4. -3. -3. -3. -3. -3. -2. -1. 0.
STEERING LEVEL PRES 0. 0. 1. 1. 1. 2. 2. 2. 2. 2. 2. 3. 2. 1. 1. 0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 1. 1. 1. 2. 3. 3. 3. 4. 4. 5. 5.
GOES PREDICTORS -1. -1. -1. -1. -3. -5. -7. -8. -9. -10. -12. -12. -13. -11. -9. -9.
OCEAN HEAT CONTENT 0. -0. 0. 0. 0. 0. -0. -0. -0. -0. -0. 0. 0. 0. 1. 1.
RI POTENTIAL -0. -1. -2. -3. -4. -4. -3. -1. 1. 2. 4. 4. 5. 5. 5. 5.
------------------------------------------------------------------------------
TOTAL CHANGE 0. 1. -0. -1. -2. -4. -4. -1. -0. -0. 0. 1. 1. 3. 5. 8.

CURRENT MAX WIND (KT): 30. LAT, LON: 17.3 106.8

** 2020 E. Pacific RI INDEX EP132020 THIRTEEN 08/26/20 06 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MOREMAXIMUM WIND INCREASE IN NEXT 24-h)

Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
POT = MPI-VMAX (KT) : 121.2 40.5 to 149.3 0.74 999.0
12 HR PERSISTENCE (KT) : 0.0 -22.0 to 44.0 0.33 999.0
850-200 MB SHEAR (KT) : 24.9 19.6 to 1.4 0.00 0.0
D200 (10**7s-1) : 77.4 -33.0 to 160.6 0.57 999.0
MAXIMUM WIND (KT) : 30.0 22.5 to 132.0 0.21 999.0
STD DEV OF IR BR TEMP : 12.5 37.8 to 2.1 0.71 999.0
HEAT CONTENT (KJ/CM2) : 21.2 2.7 to 106.7 0.18 999.0
BL DRY-AIR FLUX (W/M2) : 46.4 800.8 to -82.5 0.85 999.0
%area of TPW <45 mm upshear : 0.0 56.6 to 0.0 1.00 999.0
2nd PC OF IR BR TEMP : 0.9 2.2 to -1.9 0.33 999.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 0% is 0.0 times climatological mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 0% is 0.0 times climatological mean (12.6%)
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: 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Logistic: 0.0% 0.2% 0.0% 0.0% 0.0% 0.1% 0.1% 0.1%
Bayesian: 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Consensus: 0.0% 0.1% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
DTOPS: 0.0% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

## ANNULAR HURRICANE INDEX (AHI) EP132020 THIRTEEN 08/26/20 06 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=5 NFAIL=2 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

[cycloneye]

Tropical Depression Thirteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP132020
300 AM MDT Wed Aug 26 2020

The broad area of low pressure that the NHC has been tracking the
past few days has become better defined based on a 0356Z ASCAT-B
scatterometer overpass. Although the system is slightly elongated
northeast-to-southwest, the center is well defined and deep
convection has persisted west of the center despite strong easterly
vertical wind shear of 25-30 kt. Thus, the low has been upgraded to
Tropical Depression 13-E. The initial intensity of 30 kt is based
on scatterometer surface wind speeds of 30-32 kt, which are
consistent with T2.0/30-kt satellite classifications from TAFB-SAB.

The initial motion estimate is slowly north-northeastward or 025/04
kt. The depression is embedded within an east-to-west oriented
cyclonic gyre with a high-amplitude mid-level ridge located over
the southwestern U.S. and northern Mexico. These gyre will cause the
cyclone to move slowly northward today and northwestward on
Thursday, with the ridge acting as a poleward block and forcing to
system to turn west-northwestward to westward on Friday and
Saturday. On the forecast track, the cyclone is expected to remain
just offshore the southwestern coast of Mexico today and Thursday,
and pass near or just south of the southern tip of Baja California
Sur on Friday and Saturday. The NHC official track forecast closely
follows the simple consensus model TVCE, and lies a little to
the left or west of the corrected-consensus model HCCA and the
ECMWF model tracks.

Strong easterly shear is forecast to persist through the next 24
hours, so little if any strengthening is expected during that time.
In fact, convection is likely to erode a little during the day
today, and then redevelop closer to the center tonight when the
shear begins to abate somewhat. In the 36-60 hour period, the shear
is forecast to weaken considerably from the northeast, allowing for
some slight strengthening to occur. However, the intensity is not
expected to increase to more than 35-40 kt, with the strongest
winds and heaviest rains remaining offshore the southwestern coast
of Mexico. For those reason, a tropical warning has not been issued
for southwestern Mexico at this time. The official intensity
forecast follows a blend of the HCCA, HWRF, and ECMWF models
intensity forecasts.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 17.5N 106.7W 30 KT 35 MPH
12H 26/1800Z 18.1N 106.3W 30 KT 35 MPH
24H 27/0600Z 19.0N 106.3W 35 KT 40 MPH
36H 27/1800Z 20.1N 107.0W 35 KT 40 MPH
48H 28/0600Z 21.3N 108.1W 35 KT 40 MPH
60H 28/1800Z 22.3N 109.4W 35 KT 40 MPH
72H 29/0600Z 23.3N 111.3W 30 KT 35 MPH
96H 30/0600Z 23.3N 114.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 31/0600Z 22.7N 115.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Stewart

[Yellow Evan]

000
WTPZ43 KNHC 261454 CCA
TCDEP3

Tropical Depression Thirteen-E Discussion Number 2
NWS National Hurricane Center Miami FL EP132020
900 AM MDT Wed Aug 26 2020

CORRECTED ADVISORY NUMBER

The depression remains poorly organized this morning with the
ill-defined surface circulation decoupled well to the east of the
convective mass. Subjective satellite intensity estimates from
both TAFB and SAB support 30 kt for this advisory.

UW-CIMSS shear analysis product shows stiff 20-25 kt of
east-northeasterly shear impinging on the east portion of the
depression. Both the FV3/GFS and ECMWF SHIPS statistical-dynamical
intensity models indicate that the strong shear will persist
through the forecast period. Consequently, little strengthening is
expected during the next several days. Because of the vertical
direction and magnitude, the forecast tropical-storm-force winds
and the heaviest rainfall should remain offshore of the
southwestern coast of Mexico. The NHC intensity forecast follows a
blend of the multi-model intensity guidance, and the global models
beyond the 48 hr period which indicate the depression degenerating
into a remnant low on day 3, and dissipation by day 5.

The initial motion is estimated to be a drift east-northeastward,
or 065/2 kt. The cyclone is embedded within an
northeast-to-southwest oriented cyclonic gyre, similar to a reverse
monsoon trough that typically forms in the western Pacific during
the summer months. The depression is forecast to drift today in a
general east-northeast to northeast direction followed by a turn
slowly north-northeastward tonight. A motion toward the
north-northwest is expected on Thursday. Afterward, a
mid-tropospheric ridge anchored over the southwestern U.S. should
force the cyclone west-northwestward to westward on Friday and
Saturday. On the forecast track, the depression should remain just
offshore the southwestern coast of Mexico today and Thursday, and
pass near or just south of the southern tip of Baja California Sur
on Friday and Saturday. The official track forecast is basically
an update of the previous advisory and is nudged toward the NOAA
HFIP Corrected Consensus model.


FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 17.3N 106.1W 30 KT 35 MPH
12H 27/0000Z 18.1N 106.1W 30 KT 35 MPH
24H 27/1200Z 19.0N 106.3W 35 KT 40 MPH
36H 28/0000Z 20.4N 107.2W 35 KT 40 MPH
48H 28/1200Z 21.4N 108.5W 30 KT 35 MPH
60H 29/0000Z 22.2N 110.1W 30 KT 35 MPH
72H 29/1200Z 22.6N 112.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 30/1200Z 22.6N 114.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 31/1200Z...DISSIPATED

$$
Forecaster Roberts

[Yellow Evan]

26/1720 UTC 17.5N 105.9W T1.5/2.0 13E -- East Pacific

[Extratropical94]

So apparently this depression is now TS Hernan.

13E HERNAN 200826 1800 17.5N 105.9W EPAC 35 1004

[Extratropical94]

Tropical Storm Hernan Discussion Number 3
NWS National Hurricane Center Miami FL EP132020
400 PM CDT Wed Aug 26 2020

Despite the rather poor presentation in satellite imagery, a recent
ASCAT overpass showed that tropical-storm-force winds partially
associated with a broader scale monsoon gyre are occurring over the
southern portion of the circulation about 50-90 n mi from the
center. Based on the wind data, the initial intensity has been
raised to 35 kt, and the depression has been upgraded to Tropical
Storm Hernan.

Hernan is a sheared tropical cyclone, with only a small area of deep
convection just to the south of the center. The SHIPS guidance
indicates that this shear will continue throughout the forecast
period. While the cyclone remains over very warm waters of about 29
degrees C for the next 24-36 h, there should be sufficient
convection to maintain Hernan's current intensity. However, after 36
h the cyclone will move over relatively cooler waters of about 26
C. These very marginal water temperatures combined with the ongoing
shear should cause Hernan to weaken, and the system is expected to
degenerate to a remnant low by 60 h, as indicated by the GFS
simulated satellite. The NHC intensity is a blend of the various
corrected consensus aids and the SHIPS intensity guidance.

Hernan appears to have made its anticipated turn to the northeast
and the initial motion is 040/5 kt. The cyclone is expected to turn
north then northwest over the next 24 h as it pivots around inside a
cyclonic gyre that includes Tropical Depression Fourteen-E to its
west. After that time, Hernan should be steered west-northwestward
to westward by a mid-tropospheric ridge anchored over the
southwestern U.S.. On this forecast track, Hernan and most of its
winds and convection should remain just offshore the southwestern
coast of Mexico today and Thursday, and pass near or just south of
the southern tip of Baja California Sur on Friday and Saturday. The
official NHC forecast is little changed from the previous one, and
is near the various consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 17.7N 105.8W 35 KT 40 MPH
12H 27/0600Z 18.4N 105.7W 35 KT 40 MPH
24H 27/1800Z 19.5N 106.1W 35 KT 40 MPH
36H 28/0600Z 20.7N 107.3W 35 KT 40 MPH
48H 28/1800Z 21.7N 108.9W 30 KT 35 MPH
60H 29/0600Z 22.2N 110.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 29/1800Z 22.5N 112.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 30/1800Z 22.4N 115.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 31/1800Z...DISSIPATED

$$
Forecaster Latto

[Blinhart]

So is Laura helping these Pacific storms ventilate?

[Yellow Evan]

ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM

Tropical Storm Hernan Discussion Number 4
NWS National Hurricane Center Miami FL EP132020
1000 PM CDT Wed Aug 26 2020

Hernan remains a sheared tropical cyclone with a new burst of deep
convection, characterized by cloud tops of -75C to -85C, having
developed near and southwest of the well-defined low-level
circulation center. The initial intensity remains 35 kt based on a
TAFB Dvorak satellite classification of T2.5/35 kt using a shear
pattern.

Up until a few hours ago, Hernan had been moving slowly
north-northeastward, but the motion is now estimated to be northward
or 360/05 kt. Hernan is forecast to remain trapped within and move
around the northeastern periphery of a large-scale, eastern North
Pacific monsoon gyre during the next few days. This is expected to
result in a slow northward motion tonight, followed by a turn toward
the northwest on Thursday, and a west-northwestward motion on
Friday. By Saturday, Hernan is forecast to degenerate into a remnant
low pressure system and be steered generally westward by the
low-level easterly flow on the north side of the gyre. On the
forecast track, Hernan and most of its significant winds and
convection should remain just offshore the southwestern coast of
Mexico tonight and Thursday, and pass near or just south of the
southern tip of Baja California Sur on Friday and Saturday. The new
NHC track is a very similar to the previous advisory track, and lies
close to the simple track consensus models TVCE and GFEX, and lies
to the left of the NOAA-HCCA corrected-consensus model.

Hernan is expected to remain a sheared tropical cyclone throughout
its lifetime due to moderate to strong east to northeasterly
vertical wind shear. However, the cyclone will also be over warm
waters and within a moist mid-level environment for the next 48
hours or so. Although the official intensity forecast calls for no
change in strength, some slight intensification to 40 kt can't be
ruled out, especially tonight during the approaching convective
maximum period. By 60 hours and beyond, Hernan is forecast to move
over marginal sea-surface temperatures and be affected by strong
easterly shear of at least 20 kt, which should cause the cyclone to
weaken into a remnant low. The NHC intensity forecast follows the
IVCN intensity consensus model.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0300Z 18.3N 105.8W 35 KT 40 MPH
12H 27/1200Z 19.0N 105.9W 35 KT 40 MPH
24H 28/0000Z 20.2N 106.6W 35 KT 40 MPH
36H 28/1200Z 21.4N 108.1W 35 KT 40 MPH
48H 29/0000Z 22.0N 109.9W 30 KT 35 MPH
60H 29/1200Z 22.5N 112.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 30/0000Z 22.5N 113.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 31/0000Z 22.4N 115.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 01/0000Z...DISSIPATED

$$
Forecaster Stewart