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2020 East & Central Pacific Hurricane Season


jgf
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INVEST 90E - unlikely to amount to much.., but still.., kind of an early start...

 

NOAA NWS National Hurricane Center
6 hours ago

NHC has issued a Special Tropical Weather Outlook regarding a large area of disturbed weather associated with a trough of low pressure that has formed over the eastern North Pacific Ocean several hundred miles south of the southern tip of the Baja California peninsula.

Environmental conditions are favorable for some gradual development during the next couple of days as the disturbance moves slowly northwestward. By late this weekend, conditions will become less conducive for development. The next Special Tropical Weather Outlook on this system will be issued by 2 p.m. PDT Friday, or earlier, if necessary - www.hurricanes.gov

The eastern North Pacific hurricane season officially begins on May 15th, and on June 1st for the Atlantic basin.

No photo description available.

 

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  • 2 months later...
30 minutes ago, Floydbuster said:

NHC went with 80 mph. I would have guessed atleast 105 mph, maybe even higher.

Yeah, looking pretty impressive and good conditions to strengthen. I'm closely following the track, ecmwf UK and HWRF has been missing the big island to the north which would significantly affect the local impact here in Oahu. Seems like a lot of the other models take a more direct course for big island which would shred it apart and weaken considerably before impacting the other islands.

I live out in an exposed part of the windward side of Oahu so things could get interesting.

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  • 3 weeks later...

Things are really popping off the Mexican coast... 

two_pac_5d0.png.ef9272b4ce08074a68a7534a94cbd065.png

 

Image description: 5 day forecast for the eastern north pacific from the National Hurricane Center as of 8-14-20. The map shows depression ten-e along with three areas with an over 60% chance of development 

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      ** 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%

Not too shaby

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Jesus... TS to Cat 4 in 48 hours

Tropical Storm Genevieve Discussion Number   4
NWS National Hurricane Center Miami FL       EP122020
400 AM CDT Mon Aug 17 2020

Genevieve's infrared satellite presentation continues to improve in 
organization, with the center embedded beneath a Central Dense 
Overcast and strong convection occurring in two bands to the 
southwest and northwest of the center.  There has been a dearth of 
microwave data over the cyclone during the past few hours, so it's 
difficult to know how the internal structure has changed, but 
subjective and objective satellite estimates all support raising 
the intensity to 55 kt.

Genevieve's motion has not changed--still west-northwestward (290 
degrees) at 16 kt.  The cyclone will be moving along the periphery 
of a strong mid-level ridge which extends from the southwestern 
United States southeastward into Mexico.  This ridge should steer 
Genevieve toward the west-northwest or northwest for the entire 
5-day forecast period, but small variations in the strength and 
orientation of the ridge will play a role in how close Genevieve 
gets to the southern portion of the Baja California peninsula.  The 
track models are showing a slight bend to the storm's forecast path 
in 2-3 days, with the most recent run of the GFS showing a much 
closer approach to the Baja California peninsula.  At this stage, 
however, that model is a bit of an outlier compared to the other 
guidance.  Still, given the new set of models, the updated NHC 
track forecast has been shifted north and east of the previous 
track prediction, and it lies very close to the ECMWF, HWRF, and 
HCCA model solutions.

Some of the intensity guidance for Genevieve is incredible.  Due to 
low shear, very warm water, and high atmospheric moisture, several 
of the various SHIPS Rapid Intensification (RI) indices for the 
12-, 24-, and 36-hour forecast periods are between 95 and 100 
percent--numbers that suggest there is little doubt that Genevieve 
will go through a period of significant RI during the next couple 
of days.  RI is explicitly shown in the NHC intensity forecast, 
which is very near the HCCA and Florida State Superensemble 
solutions and shows Genevieve peaking as a category 4 hurricane in 
about 48 hours.  Amazingly, the LGEM and COAMPS-TC models are even 
higher than what is indicated in the official forecast, showing a 
peak intensity of 125-130 kt.  A combination of cooler waters and 
increasing shear (especially at the end of the forecast period) is 
expected to cause weakening on days 3 through 5.

Large swells generated by Genevieve are expected to begin affecting 
portions of the coast of southern Mexico today and will spread 
northward along the coast of Mexico to the Baja California 
peninsula by Wednesday.


FORECAST POSITIONS AND MAX WINDS

INIT  17/0900Z 13.3N 101.7W   55 KT  65 MPH
 12H  17/1800Z 14.4N 104.0W   75 KT  85 MPH
 24H  18/0600Z 16.0N 106.7W   95 KT 110 MPH
 36H  18/1800Z 17.4N 108.7W  110 KT 125 MPH
 48H  19/0600Z 18.7N 110.1W  120 KT 140 MPH
 60H  19/1800Z 20.0N 111.2W  115 KT 130 MPH
 72H  20/0600Z 21.3N 112.3W  100 KT 115 MPH
 96H  21/0600Z 23.5N 115.0W   70 KT  80 MPH
120H  22/0600Z 25.5N 118.5W   45 KT  50 MPH

$$
Forecaster Berg
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      ** 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  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%

Not too shaby
 

That output is just ridiculous. Don't ever recall seeing 100% values for such large gains in a 48 hr period. Shear does increase in the late forecast period ~72 hrs; however, MPI is so high this may be one of those easier calls for a Cat 5. Hopefully it stays away from the southern Baja.

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Actually I take that back. There is never an easier Category 5 call with a TC at TS intensity even with SHIPS values this ridiculous. The evolution of the vortex will still have most sway on how rapid it can accelerate spin. This is most dependent on convective structure; therefore, if the cyclone is faster at forming a very organized eyewall band versus prolonged competing convective cells, it might reach Cat 5. The issue is Genevieve only having roughly 60 hrs before atmospheric conditions decrease its MPI. So even though intensity modeling is very rapid with intensification, Genevieve may still not have time to iron out the internal structure of its vortex to fulfill an MPI above Category 4 before shear increases. I.e., atmospheric conditons may be near perfect out ~60 hrs, but Genevieve's structural evolution might still not be fast enough. At any rate, Cat 5s are never easier to forecast unless you already have a well-developed hurricane, adequate time and rapid intensification is already underway.

b1351d8b0f7c3046dfe3ad024ef02b02.jpg&key=2e128cba875fc6dbd8d01ed7bbd06c18b71d1940ea96c5c3b7f34a0f20941e17

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2 hours ago, Windspeed said:

 

That output is just ridiculous. Don't ever recall seeing 100% values for such large gains in a 48 hr period. Shear does increase in the late forecast period ~72 hrs; however, MPI is so high this may be one of those easier calls for a Cat 5. Hopefully it stays away from the southern Baja.

I think Patricia was close,  but I don't recall what the exact percentages were.

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1 hour ago, Amped said:

Upgraded to Hurricane. 

RAW ADT is 6.0 with 1.7T/6hr constraint set.  They only set that limit when a storm is about to nuke.

425 
WTPZ42 KNHC 171451
TCDEP2

Hurricane Genevieve Discussion Number   5
NWS National Hurricane Center Miami FL       EP122020
1000 AM CDT Mon Aug 17 2020

Data from a recent SSMIS microwave overpass reveals that an eye is 
trying to form underneath the deep convection of Genevieve, but 
there is some dry air near the center that may be disrupting the 
formation of a solid eyewall. Despite that dry air, large bands 
continue to the southwest and northwest of the center, and the deep 
convection over the center is expanding in size. The latest Dvorak 
satellite intensity estimates from both TAFB and SAB support raising 
the initial intensity to 65 kt, making Genevieve the third hurricane 
of the 2020 Eastern Pacific hurricane season.

Genevieve jogged a little northwest over the past few hours, but the
longer term motion has been west-northwest at 16 kt. The main
steering mechanism for the cyclone is a strong mid-level ridge which
extends from the southwestern United States southeastward into
Mexico. The model guidance varies slightly on the strength and
orientation of this ridge over the next few days, which could play a
role in how close Genevieve gets to the southern portion of the Baja
California Peninsula. The GFS is the farthest east, but still keeps
the center well offshore, while The UKMET is the westernmost
solution. Overall, the guidance has changed little since early this 
morning, and the official forecast is very near the previous track,
which lies near the TVCX/TVCE consensus.

The small amount of dry air near the center should get worked out 
of the circulation shortly, and there is high confidence that 
the rapid intensification of Genevieve will continue for the next 
24-36 h. The SHIPS Rapid Intensification Index (RII) shows a greater 
than 95 percent chance of a 30 kt increase in strength in the next 
24 h, and nearly an 80 percent chance of a 45 kt increase in 
the next 36 h. The global, regional, and consensus intensity aids 
all agree that rapid intensification will occur in one form or 
another during this time frame as well. The official intensity 
forecast is a blend of the HFIP corrected consensus and the IVCN 
consensus, and is very close to the previous forecast.

Large swells generated by Genevieve are expected to begin affecting
portions of the coast of southern Mexico today and will spread
northward along the coast of Mexico to the Baja California
peninsula by Wednesday.


FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 14.3N 103.0W   65 KT  75 MPH
 12H  18/0000Z 15.4N 105.0W   85 KT 100 MPH
 24H  18/1200Z 17.0N 107.3W  105 KT 120 MPH
 36H  19/0000Z 18.4N 109.0W  120 KT 140 MPH
 48H  19/1200Z 19.7N 110.2W  120 KT 140 MPH
 60H  20/0000Z 21.0N 111.1W  110 KT 125 MPH
 72H  20/1200Z 22.2N 112.4W   95 KT 110 MPH
 96H  21/1200Z 24.3N 115.2W   65 KT  75 MPH
120H  22/1200Z 26.4N 118.7W   45 KT  50 MPH

$$
Forecaster Latto

 

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Genevieve is now a major hurricane. Still forecast to peak as a Category 4 and still intensifying; perhaps not as rapidly as some of the guidance suggested, though still plenty swift to be in upper RI range. The system was classified just 44 hours ago. The chaotic nature of an eyewall core vortex evolving. It still has plenty of time to make a run at Category 5 as favorable conditions will persist 12-24 hrs and MPI could be reached by this evening. By Wednesday evening conditions will not be as supportive. Regardless of peak intensity, looking for Genevieve to ramp up deeper internal convection today.86388d7be17d7f9daa1af9554ca5319c.gif&key=765227c1ff4384222c825e91394a0d13569034a4698b0a2614cdc9eb76108eb9

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Genevieve now a Category 4.

Maximum sustained winds have increased to near 130 mph (210 km/h)
with higher gusts.  Genevieve is a category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale.  Additional rapid strengthening
is possible during the next 12 to 24 hours.  Rapid weakening is
forecast to begin by late Wednesday and should continue through the
end of the week.

 

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Genevieve still has a beautiful structure and warm eye, however, the core eyewall convection has seemingly reached a steady-state plateau and intensification has ceased. This is likely due to something I had forgotten to consider earlier. SSTs...

Genevieve is traversing Elida's wake. Though immediate shallow layer SSTs are likely still 28°C, water below the 26° isotherm in the colder thermalcline has likely upwelled. This may not have even had time to show correctly on SST analysis as this area has been cloud covered.

So there you go, Genevieve has peaked and will probably hold steady until tomorrow when weakening begins.71fe0d34c4ab3478c20b19186d593b4d.gif

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