EPAC: GENEVIEVE - Post-Tropical

[Visioen]

After tracking those small messy things in the Atlantic I almost forgot what a real storm looks like.

[Kingarabian]

A 4 hour old AMSR2 pass shows a core is indeed developing.

[Kingarabian]

I think it'll be 3.0 on Dvorak by the time the next advisory comes out.

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 16 AUG 2020 Time : 222020 UTC
Lat : 12:18:40 N Lon : 99:32:57 W


CI# /Pressure/ Vmax
2.6 /1006.2mb/ 37.0kt


Final T# Adj T# Raw T#
2.6 2.8 3.6

Center Temp : -58.4C Cloud Region Temp : -59.9C

Scene Type : UNIFORM CDO CLOUD REGION

[Yellow Evan]

Might be a little more banding dominant than I'd like but this also has a good moisture envelope. Ceiling for Genevieve is probably a Category 5 threshold though given this has 60 hours over 29-30C and low shear.

[Kingarabian]

Might be a little more banding dominant than I'd like but this also has a good moisture envelope. Ceiling for Genevieve is probably a Category 5 threshold though given this has 60 hours over 29-30C and low shear.

Also convection looks a little warm considering its location over those 29-30C SSTs.



But the structure looks very good. Best since Douglas.

[Visioen]

Moisture anyone? We're out of shear though.

[aspen]

Might be a little more banding dominant than I'd like but this also has a good moisture envelope. Ceiling for Genevieve is probably a Category 5 threshold though given this has 60 hours over 29-30C and low shear.

Also convection looks a little warm considering its location over those 29-30C SSTs.

https://i.imgur.com/zMlnu7s.png

But the structure looks very good. Best since Douglas.

It hasn’t reach Dmax yet. Once it does, convection should become much deeper.

Or it’s swallowing in dry air and will continue to do so and struggle for days. That’ll be annoying, because we totally haven’t seen that this year.

[Chris90]

System looks really good, and the NHC definitely has confidence in her since their first forecast was so aggressive.

My only hang up right now is that Cristina looked really good on microwave right out the gate and that tight structure she had fell apart pretty quickly, then she struggled for awhile, so Genevieve is going to need to work a little harder to earn my trust.

The EPAC is making me sound like a divorcée who has been burned in the past.

[Kingarabian]

16/2330 UTC 12.3N 99.3W T3.0/3.0 GENEVIEVE -- East Pacific

[aspen]

A nice hot tower is firing off near the center. 00z best track has it at 45 kt/1001 mbar.

[1900hurricane]

Straight from the f-deck:

EP, 12, 202008162249, 30, SSMS, C, , 1200N, 9935W, , 2, , , , 3, , , , , , , , , , , , 3, , , , NHC, SRS, , , , , , , , , SSMS, , , , , , , , , , , , , , , , , , , 3, pbo tight intelockng bands & psbl eye forming

[gatorcane]

18 HWRF has this bottoming out at 947MB. That is in 51 hours so would be remarkable RI to get there which is certainly possible.

[aspen]

18 HWRF has this bottoming out at 947MB. That is in 51 hours so would be remarkable RI to get there which is certainly possible.

It’s not the most remarkable RI. With a current pressure of 1001 mbar, that’s a drop of 1.06mbar/hr, or ~25 mbar/day. That’s actually not that much, and would only get it to high end Cat 1 status by the end of the day tomorrow. Assuming Genevieve’s moisture bubble can keep out dry air, she can achieve far more than that.

[aspen]

Outflow is excellent in all quadrants, and more convection is firing around the center. She’s about to take off.

I would post the latest water vapor image from Tropical Tidbits but I’m on mobile, so I can’t.

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2020 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* GENEVIEVE EP122020 08/17/20 00 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
V (KT) NO LAND 45 54 62 71 80 96 104 107 108 100 90 79 66 59 51 43 35
V (KT) LAND 45 54 62 71 80 96 104 107 108 100 90 79 66 59 51 43 35
V (KT) LGEM 45 53 60 68 76 93 109 119 113 98 83 65 51 41 33 27 22
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 3 5 6 2 3 2 9 2 3 6 12 15 18 13 12 14 21
SHEAR ADJ (KT) 0 4 6 5 3 -2 -6 -3 -3 0 2 0 4 3 9 0 8
SHEAR DIR 54 10 345 43 23 119 141 62 103 107 147 159 193 213 206 199 207
SST (C) 29.8 30.2 30.3 30.3 30.1 29.7 29.6 28.9 26.8 25.9 24.9 23.9 22.7 22.3 21.8 21.6 21.2
POT. INT. (KT) 165 170 171 170 168 163 161 154 132 122 112 102 89 84 79 78 74
200 MB T (C) -52.5 -52.7 -52.8 -52.6 -52.3 -52.9 -51.9 -52.3 -51.3 -51.2 -50.4 -50.5 -49.8 -50.3 -50.1 -50.4 -50.4
200 MB VXT (C) 0.1 0.1 0.1 0.2 0.2 0.4 0.5 0.6 0.5 0.5 0.7 0.9 0.7 0.9 0.8 0.7 0.7
TH_E DEV (C) 5 4 4 6 6 6 8 6 6 5 4 2 0 0 0 0 0
700-500 MB RH 82 82 81 81 79 80 77 76 69 61 56 54 49 49 46 46 41
MODEL VTX (KT) 17 18 19 20 21 23 25 27 31 30 29 27 24 24 22 20 17
850 MB ENV VOR 18 13 10 20 29 41 61 61 85 76 77 82 58 67 40 29 0
200 MB DIV 106 84 71 96 135 122 130 84 76 30 10 5 -5 13 1 5 5
700-850 TADV -1 -11 -14 -12 -11 -6 0 -1 -4 -11 -1 0 6 4 7 11 16
LAND (KM) 466 462 460 451 458 468 518 433 364 367 426 502 561 690 821 931 948
LAT (DEG N) 12.1 12.8 13.5 14.2 14.8 16.3 17.8 19.2 20.9 22.0 22.7 23.8 25.3 xx.x xx.x xx.x xx.x
LONG(DEG W) 99.6 101.1 102.7 104.1 105.6 108.0 109.8 111.3 112.8 114.2 115.8 117.6 119.9 xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 16 17 16 15 15 13 11 11 10 8 9 11 11 8 8 11 11
HEAT CONTENT 28 48 44 39 32 27 26 14 1 0 0 0 0 0 0 0 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):285/ 16 CX,CY: -14/ 4
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 494 (MEAN=587)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 6.9 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 99.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 77.2

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. 10. 13. 16. 17. 18. 17. 16. 14. 10. 7. 4.
VERTICAL SHEAR MAG 1. 1. 2. 3. 5. 6. 8. 9. 10. 9. 8. 7. 6. 4. 3. 1.
VERTICAL SHEAR ADJ -0. -1. -1. -1. -1. -0. 0. 0. 0. 0. -0. -0. 0. 0. -0. -0.
VERTICAL SHEAR DIR 0. 0. 1. 1. 1. 1. 1. 1. -0. -1. -1. -1. -0. -0. 0. 0.
PERSISTENCE 3. 5. 5. 5. 4. 3. 3. 2. 2. 2. 2. 3. 2. 3. 3. 3.
200/250 MB TEMP. -0. -0. -0. -1. -1. -1. -1. -1. -1. -1. 0. 1. 1. 2. 3. 4.
THETA_E EXCESS -0. -0. -1. -1. -1. -1. -0. -1. -1. -2. -2. -4. -5. -6. -7. -9.
700-500 MB RH 0. 0. 1. 1. 1. 1. 1. 2. 1. 1. 1. 1. 1. 1. 1. 1.
MODEL VTX TENDENCY 0. 1. 2. 3. 5. 7. 12. 19. 18. 16. 13. 8. 7. 4. 2. -1.
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. 2. 3. 4. 6. 6. 5. 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. 1. 1. 1. 2. 3. 3. 3. 2. 2. 2. 2. 2. 1. 1. -0.
STEERING LEVEL PRES -0. -0. -1. -1. -1. -1. -1. -1. -1. -2. -2. -2. -1. -1. -1. -0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 1. 1. 2. 2. 3. 3. 3. 4. 4. 5.
GOES PREDICTORS 2. 3. 3. 3. 3. 3. 3. 2. 2. 2. 3. 3. 3. 2. 2. 1.
OCEAN HEAT CONTENT -0. 0. 0. 0. 0. 1. 1. 1. 0. 0. 0. 0. 0. 0. 1. 2.
RI POTENTIAL 2. 6. 10. 15. 24. 22. 13. 4. -2. -8. -12. -14. -15. -15. -15. -15.
------------------------------------------------------------------------------
TOTAL CHANGE 9. 17. 26. 35. 51. 59. 62. 63. 55. 45. 34. 21. 14. 6. -2. -10.

CURRENT MAX WIND (KT): 45. LAT, LON: 12.1 99.6

** 2020 E. Pacific RI INDEX EP122020 GENEVIEVE 08/17/20 00 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) : 123.8 40.5 to 149.3 0.77 18.8
12 HR PERSISTENCE (KT) : 15.0 -22.0 to 44.0 0.56 16.3
850-200 MB SHEAR (KT) : 3.9 19.6 to 1.4 0.86 19.5
D200 (10**7s-1) : 98.4 -33.0 to 160.6 0.68 15.9
MAXIMUM WIND (KT) : 45.0 22.5 to 132.0 0.64 11.1
STD DEV OF IR BR TEMP : 6.9 37.8 to 2.1 0.87 12.6
HEAT CONTENT (KJ/CM2) : 38.2 2.7 to 106.7 0.34 4.7
BL DRY-AIR FLUX (W/M2) : 29.8 800.8 to -82.5 0.87 -15.9
%area of TPW <45 mm upshear : 0.0 56.6 to 0.0 1.00 6.1
2nd PC OF IR BR TEMP : -0.3 2.2 to -1.9 0.62 1.1

SHIPS Prob RI for 20kt/ 12hr RI threshold= 51% is 8.2 times climatological mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 98% is 7.8 times climatological mean (12.6%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 90% is 10.5 times climatological mean ( 8.6%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 81% is 13.0 times climatological mean ( 6.2%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 65% is 15.6 times climatological mean ( 4.2%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 100% is 14.9 times climatological mean ( 6.7%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 100% is 16.9 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 58% is 12.4 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: 51.4% 97.7% 90.1% 80.7% 65.3% 100.0% 100.0% 58.4%
Logistic: 54.1% 87.9% 81.5% 75.3% 23.3% 91.0% 76.5% 45.9%
Bayesian: 45.0% 79.2% 81.4% 70.1% 9.8% 60.4% 45.8% 22.0%
Consensus: 50.2% 88.3% 84.3% 75.4% 32.8% 83.8% 74.1% 42.1%
DTOPS: 24.0% 60.0% 50.0% 24.0% 15.0% 41.0% 37.0% 23.0%

## ANNULAR HURRICANE INDEX (AHI) EP122020 GENEVIEVE 08/17/20 00 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) ##

[cycloneye]

New peak up to cat 4.

Tropical Storm Genevieve Discussion Number 3
NWS National Hurricane Center Miami FL EP122020
1000 PM CDT Sun Aug 16 2020

Infrared (IR) and passive microwave (MW) satellite imagery indicate
that Genevieve has continued to rapidly intensify while becoming
better organized. A 17/0121Z SSMI/S MW image showed that the
cyclone had already developed a 15-nmi-diameter, ragged mid-level
eye, while both IR and MW data indicate tight banding features
spiraling into a compact inner-core convective region. The initial
intensity of 50 kt is based on unanimous T3.0/45 kt satellite
classifications from TAFB and SAB, with the aforementioned eye
feature nudging upward the final intensity assessment.

The initial motion estimate remains west-northwestward or 290/16 kt.
The track forecast and reasoning remain unchanged and fairly
straightforward. Genevieve is expected to move generally
west-northwestward around the southwestern periphery of a sprawling
deep-layer ridge located over the western United States and
northern and central Mexico throughout the forecast period. The new
NHC track forecast is very similar to the previous advisory track,
and lies near the middle of the tightly packed consensus track model
forecasts.

Now that Genevieve has developed a tight inner-core wind field and
an eye feature, it isn't a question of will the cyclone rapidly
strengthen, but rather how quickly and how much will the
strengthening be! The deep-layer and mid-level vertical wind shear
parameters are forecast to be weak at less than 5 kt through 72
hours, while the upper-level outflow pattern is expected to steadily
improve during that time, including the development of dual outflow
channels to the north and south. These very favorable atmospheric
conditions will coincide with a very moist mid-level regime and
sea-surface temperatures (SST) of at least 30 deg C. As a result,
the intensity forecast has been nudged upward, with rapid
intensification (RI) of about 30 kt expected during next 24 h,
followed by a slightly faster rate of RI in the 24-48 hour time
frame when the dual outflow channels will be present. By 60-72
hours, Genevieve is expected to be moving over shallower warm
water, which should result in significant cold upwelling and the
onset weakening. More rapid weakening is forecast thereafter due to
the cyclone moving over 23-25 deg C SSTs. The official intensity is
near the upper end of the guidance envelope, but remains below the
ECMWF-based SHIPS model forecast which brings Genevieve to near 130
kt in 48-60 hours.

Although the tropical cyclone is forecast to remain well offshore of
the southern coast of Mexico, large swells generated by the
strengthening system are expected to begin affecting portions of
the coast of southern Mexico over the next day or so.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 12.4N 100.4W 50 KT 60 MPH
12H 17/1200Z 13.4N 102.7W 60 KT 70 MPH
24H 18/0000Z 14.8N 105.7W 75 KT 85 MPH
36H 18/1200Z 16.3N 108.2W 95 KT 110 MPH
48H 19/0000Z 17.7N 110.1W 115 KT 130 MPH
60H 19/1200Z 19.1N 111.5W 120 KT 140 MPH
72H 20/0000Z 20.4N 112.9W 105 KT 120 MPH
96H 21/0000Z 22.7N 116.0W 80 KT 90 MPH
120H 22/0000Z 24.7N 119.7W 55 KT 65 MPH

$$
Forecaster Stewart

[aspen]

New peak up to cat 4.

Tropical Storm Genevieve Discussion Number 3
NWS National Hurricane Center Miami FL EP122020
1000 PM CDT Sun Aug 16 2020

Infrared (IR) and passive microwave (MW) satellite imagery indicate
that Genevieve has continued to rapidly intensify while becoming
better organized. A 17/0121Z SSMI/S MW image showed that the
cyclone had already developed a 15-nmi-diameter, ragged mid-level
eye, while both IR and MW data indicate tight banding features
spiraling into a compact inner-core convective region. The initial
intensity of 50 kt is based on unanimous T3.0/45 kt satellite
classifications from TAFB and SAB, with the aforementioned eye
feature nudging upward the final intensity assessment.

The initial motion estimate remains west-northwestward or 290/16 kt.
The track forecast and reasoning remain unchanged and fairly
straightforward. Genevieve is expected to move generally
west-northwestward around the southwestern periphery of a sprawling
deep-layer ridge located over the western United States and
northern and central Mexico throughout the forecast period. The new
NHC track forecast is very similar to the previous advisory track,
and lies near the middle of the tightly packed consensus track model
forecasts.

Now that Genevieve has developed a tight inner-core wind field and
an eye feature, it isn't a question of will the cyclone rapidly
strengthen, but rather how quickly and how much will the
strengthening be! The deep-layer and mid-level vertical wind shear
parameters are forecast to be weak at less than 5 kt through 72
hours, while the upper-level outflow pattern is expected to steadily
improve during that time, including the development of dual outflow
channels to the north and south. These very favorable atmospheric
conditions will coincide with a very moist mid-level regime and
sea-surface temperatures (SST) of at least 30 deg C. As a result,
the intensity forecast has been nudged upward, with rapid
intensification (RI) of about 30 kt expected during next 24 h,
followed by a slightly faster rate of RI in the 24-48 hour time
frame when the dual outflow channels will be present. By 60-72
hours, Genevieve is expected to be moving over shallower warm
water, which should result in significant cold upwelling and the
onset weakening. More rapid weakening is forecast thereafter due to
the cyclone moving over 23-25 deg C SSTs. The official intensity is
near the upper end of the guidance envelope, but remains below the
ECMWF-based SHIPS model forecast which brings Genevieve to near 130
kt in 48-60 hours.

Although the tropical cyclone is forecast to remain well offshore of
the southern coast of Mexico, large swells generated by the
strengthening system are expected to begin affecting portions of
the coast of southern Mexico over the next day or so.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 12.4N 100.4W 50 KT 60 MPH
12H 17/1200Z 13.4N 102.7W 60 KT 70 MPH
24H 18/0000Z 14.8N 105.7W 75 KT 85 MPH
36H 18/1200Z 16.3N 108.2W 95 KT 110 MPH
48H 19/0000Z 17.7N 110.1W 115 KT 130 MPH
60H 19/1200Z 19.1N 111.5W 120 KT 140 MPH
72H 20/0000Z 20.4N 112.9W 105 KT 120 MPH
96H 21/0000Z 22.7N 116.0W 80 KT 90 MPH
120H 22/0000Z 24.7N 119.7W 55 KT 65 MPH

$$
Forecaster Stewart

This is the first time I’ve seen anyone use an exclamation point in a Tropical Weather Discussion. Stewart sure seems excited about Genevieve.

[gfsperpendicular]

New peak up to cat 4.

-

This is the first time I’ve seen anyone use an exclamation point in a Tropical Weather Discussion. Stewart sure seems excited about Genevieve.

I literally jumped when I read that. Mr. Stewart getting feisty!

[Yellow Evan]

 https://twitter.com/wxtrackercody/status/1295159973542916097

[storminabox]

New peak up to cat 4.

Tropical Storm Genevieve Discussion Number 3
NWS National Hurricane Center Miami FL EP122020
1000 PM CDT Sun Aug 16 2020

Infrared (IR) and passive microwave (MW) satellite imagery indicate
that Genevieve has continued to rapidly intensify while becoming
better organized. A 17/0121Z SSMI/S MW image showed that the
cyclone had already developed a 15-nmi-diameter, ragged mid-level
eye, while both IR and MW data indicate tight banding features
spiraling into a compact inner-core convective region. The initial
intensity of 50 kt is based on unanimous T3.0/45 kt satellite
classifications from TAFB and SAB, with the aforementioned eye
feature nudging upward the final intensity assessment.

The initial motion estimate remains west-northwestward or 290/16 kt.
The track forecast and reasoning remain unchanged and fairly
straightforward. Genevieve is expected to move generally
west-northwestward around the southwestern periphery of a sprawling
deep-layer ridge located over the western United States and
northern and central Mexico throughout the forecast period. The new
NHC track forecast is very similar to the previous advisory track,
and lies near the middle of the tightly packed consensus track model
forecasts.

Now that Genevieve has developed a tight inner-core wind field and
an eye feature, it isn't a question of will the cyclone rapidly
strengthen, but rather how quickly and how much will the
strengthening be! The deep-layer and mid-level vertical wind shear
parameters are forecast to be weak at less than 5 kt through 72
hours, while the upper-level outflow pattern is expected to steadily
improve during that time, including the development of dual outflow
channels to the north and south. These very favorable atmospheric
conditions will coincide with a very moist mid-level regime and
sea-surface temperatures (SST) of at least 30 deg C. As a result,
the intensity forecast has been nudged upward, with rapid
intensification (RI) of about 30 kt expected during next 24 h,
followed by a slightly faster rate of RI in the 24-48 hour time
frame when the dual outflow channels will be present. By 60-72
hours, Genevieve is expected to be moving over shallower warm
water, which should result in significant cold upwelling and the
onset weakening. More rapid weakening is forecast thereafter due to
the cyclone moving over 23-25 deg C SSTs. The official intensity is
near the upper end of the guidance envelope, but remains below the
ECMWF-based SHIPS model forecast which brings Genevieve to near 130
kt in 48-60 hours.

Although the tropical cyclone is forecast to remain well offshore of
the southern coast of Mexico, large swells generated by the
strengthening system are expected to begin affecting portions of
the coast of southern Mexico over the next day or so.



FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 12.4N 100.4W 50 KT 60 MPH
12H 17/1200Z 13.4N 102.7W 60 KT 70 MPH
24H 18/0000Z 14.8N 105.7W 75 KT 85 MPH
36H 18/1200Z 16.3N 108.2W 95 KT 110 MPH
48H 19/0000Z 17.7N 110.1W 115 KT 130 MPH
60H 19/1200Z 19.1N 111.5W 120 KT 140 MPH
72H 20/0000Z 20.4N 112.9W 105 KT 120 MPH
96H 21/0000Z 22.7N 116.0W 80 KT 90 MPH
120H 22/0000Z 24.7N 119.7W 55 KT 65 MPH

$$
Forecaster Stewart

This is the first time I’ve seen anyone use an exclamation point in a Tropical Weather Discussion. Stewart sure seems excited about Genevieve.

I sure am excited about this storm! Hopefully it doesn't disappoint us like many other systems have this year. Considering the favorable conditions in place, the ceiling is certainly very for Genevieve and a Category 5 is not out of the question.