ATL: LARRY - Models

[jlauderdal]

06z HWRF makes this a TS at 15 hours from initialization and a hurricane on Friday.

Seems very reasonable, hwrf did ok with intense systems like IDA

[Blown Away]

Models trending W, below 20N/60W is the mark storms (Majority of the time) must stay below to impact NE Caribbean, GOM, SFL... Moving above 20N/60W still keeps Bermuda & Mid Atlantic in play...

[kevin]

HWRF has a low-end cat 3 (963mb/99kt) at +117, 03z on Sunday.

[AutoPenalti]

The gap in the ridge still seems to happen at 06z, likely if this TC developed later in the cycle, we may have a different story.

[kevin]

Now that's what I call a hurricane eye, reminds me a bit of Isabel.

[Blown Away]

06z HWRF... HWRF is a W outlier, another SW shift with 06z run... Look at the size of this storm and the eye... Wow

[kevin]

https://i.imgur.com/XToZkpz.gif
06z HWRF... HWRF is a W outlier, another SW shift with 06z run... Look at the size of this storm and the eye... Wow

Yes, HWRF is showing a very large hurricane. Of course it's one thing to model it and another thing to become reality, but that run had a hurricane with a 500 mile (800 km) diameter at the end. That's 100 miles bigger than even Irma or Katrina. We'd be talking a size almost comparable to Gilbert (575 miles).

[chaser1]

https://i.imgur.com/XToZkpz.gif
06z HWRF... HWRF is a W outlier, another SW shift with 06z run... Look at the size of this storm and the eye... Wow

Yes, HWRF is showing a very large hurricane. Of course it's one thing to model it and another thing to become reality, but that run had a hurricane with a 500 mile (800 km) diameter at the end. That's 100 miles bigger than even Irma or Katrina. We'd be talking a size almost comparable to Gilbert (575 miles).

Another Gilbert would really be something to see (from a distance lol). If not for competing MLC's, this would likely consolidate pretty quickly which I would think would favor a quicker poleward turn. Though either blob might win out, I'd guess that an eventual COC will occur at some point between the two. The broader LLC would seem to point to this. Timing, timing, timing in the tropics though. Lets see if consolidation takes a bit longer then expected, and at what latitude. Sure seems like it'll end up being one real accumulating ace-hole.

We should set up a (potential) Larry Pole LOL. What latitude will it be at when reaching 60W? I'll go with 21N

[cycloneye]

* ATLANTIC 2021 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* INVEST AL902021 08/31/21 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 30 34 38 42 49 59 72 87 101 109 113 110 111 108 109 108 107
V (KT) LAND 30 34 38 42 49 59 72 87 101 109 113 110 111 108 109 108 107
V (KT) LGEM 30 33 36 39 43 54 68 84 98 100 95 89 89 88 85 83 80
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 7 5 5 8 10 8 12 5 8 12 13 11 12 21 22 17 23
SHEAR ADJ (KT) 6 8 6 3 1 1 -2 0 1 3 1 3 3 2 0 -4 -3
SHEAR DIR 36 34 65 93 92 91 80 89 79 76 38 12 312 293 285 278 261
SST (C) 27.8 27.8 27.9 27.9 27.8 27.9 27.7 27.6 27.4 26.9 26.8 27.1 27.5 27.8 28.2 28.8 28.3
POT. INT. (KT) 136 137 138 139 137 138 134 133 130 123 123 127 132 134 140 149 143
ADJ. POT. INT. 136 137 138 139 137 138 134 133 129 119 118 122 125 123 127 136 130
200 MB T (C) -53.2 -53.1 -53.4 -53.4 -53.3 -53.4 -53.4 -53.2 -53.2 -52.9 -52.7 -51.8 -51.7 -51.5 -51.7 -51.4 -51.3
200 MB VXT (C) 0.1 0.1 0.2 0.1 0.2 0.2 0.2 0.3 0.5 0.6 0.7 0.7 0.8 1.1 1.4 1.0 1.1
TH_E DEV (C) 5 5 5 5 5 6 6 6 7 8 8 9 8 9 8 8 8
700-500 MB RH 83 82 80 80 78 73 67 65 59 51 48 46 46 49 51 54 55
MODEL VTX (KT) 17 18 17 18 21 23 28 33 38 40 41 38 38 37 41 41 43
850 MB ENV VOR 122 122 118 115 127 122 117 129 143 171 160 147 150 124 103 95 86
200 MB DIV 73 95 84 66 81 77 90 128 145 138 78 58 19 13 50 30 34
700-850 TADV -10 -8 -12 -7 -3 -9 -7 -12 -10 0 -5 0 4 9 13 4 -1
LAND (KM) 280 400 560 771 960 1360 1631 1845 1819 1727 1690 1679 1742 1778 1772 1691 1597
LAT (DEG N) 10.4 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) 18.6 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) 15 17 18 20 19 16 13 15 14 11 12 14 14 10 10 12 15
HEAT CONTENT 8 12 14 11 13 9 7 16 19 7 17 14 22 22 22 23 17

FORECAST TRACK FROM OFPI INITIAL HEADING/SPEED (DEG/KT):295/ 13 CX,CY: -11/ 5
T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 551 (MEAN=620)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 14.8 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 87.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 26.4

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
------------------------------------------------------------------------------
SAMPLE MEAN CHANGE 1. 2. 3. 4. 6. 8. 9. 10. 11. 12. 12. 13. 14. 15. 15. 16.
SST POTENTIAL 0. 1. 1. 1. 4. 9. 14. 19. 23. 25. 28. 30. 31. 32. 32. 31.
VERTICAL SHEAR MAG 1. 2. 3. 4. 5. 7. 8. 9. 8. 8. 8. 7. 6. 4. 3. 2.
VERTICAL SHEAR ADJ -0. -1. -1. -1. -2. -2. -1. -1. -1. -1. -1. -1. -1. -1. -0. -0.
VERTICAL SHEAR DIR 0. 1. 1. 2. 3. 5. 6. 8. 8. 9. 10. 10. 10. 9. 8. 8.
PERSISTENCE 1. 1. 1. 1. 1. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1.
200/250 MB TEMP. -0. -1. -1. -1. -1. -1. -1. -1. -1. -1. -2. -2. -3. -3. -3. -4.
THETA_E EXCESS -0. -0. -1. -1. -1. -2. -2. -1. -1. -1. -0. -0. 0. 0. 1. 1.
700-500 MB RH -0. -1. -1. -2. -3. -4. -5. -6. -6. -6. -5. -5. -5. -5. -5. -4.
MODEL VTX TENDENCY 0. 0. 0. 2. 4. 10. 17. 24. 27. 28. 23. 22. 19. 21. 20. 21.
850 MB ENV VORTICITY 0. 1. 1. 1. 2. 3. 4. 4. 5. 6. 7. 8. 8. 8. 9. 9.
200 MB DIVERGENCE 0. 1. 1. 1. 2. 2. 3. 3. 4. 3. 1. -1. -1. -2. -3. -4.
850-700 T ADVEC 0. -0. -0. -0. -1. -1. -1. -1. -1. -0. -0. -0. -0. -0. -0. -0.
ZONAL STORM MOTION -0. -0. 0. 0. 0. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2. 2.
STEERING LEVEL PRES 0. 0. 0. 0. 1. 0. 0. 0. 1. 1. 1. 1. 1. 0. 1. 1.
DAYS FROM CLIM. PEAK 0. -0. -0. -0. 0. 0. 0. 0. 0. -0. -0. -0. -0. -1. -1. -0.
GOES PREDICTORS 1. 1. 2. 1. 1. 1. 1. 1. 0. -0. -0. 0. 1. 2. 2. 1.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0.
RI POTENTIAL 1. 2. 3. 5. 6. 6. 4. 2. 0. -1. -2. -3. -4. -4. -4. -4.
------------------------------------------------------------------------------
TOTAL CHANGE 4. 8. 12. 19. 29. 42. 57. 71. 79. 83. 80. 81. 78. 79. 78. 77.

CURRENT MAX WIND (KT): 30. LAT, LON: 10.4 18.6

** 2021 ATLANTIC RI INDEX AL902021 INVEST 08/31/21 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
12 HR PERSISTENCE (KT) : 5.0 -49.5 to 33.0 0.66 4.0
850-200 MB SHEAR (KT) : 7.1 30.1 to 2.3 0.83 2.3
HEAT CONTENT (KJ/CM2) : 11.6 0.0 to 151.8 0.08 0.2
STD DEV OF IR BR TEMP : 14.8 36.6 to 2.8 0.64 1.9
MAXIMUM WIND (KT) : 30.0 22.5 to 137.5 0.20 0.5
BL DRY-AIR FLUX (W/M2) : 54.6 895.4 to -55.0 0.88 2.1
2nd PC OF IR BR TEMP : -0.9 2.9 to -2.9 0.66 1.1
POT = MPI-VMAX (KT) : 107.4 28.3 to 146.3 0.67 0.7
D200 (10**7s-1) : 79.8 -29.7 to 185.9 0.51 0.5
%area of TPW <45 mm upshear : 0.0 100.0 to 0.0 1.00 0.2

SHIPS Prob RI for 20kt/ 12hr RI threshold= 6% is 1.2 times climatological mean ( 4.9%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 23% is 2.1 times climatological mean (10.9%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 13% is 2.0 times climatological mean ( 6.8%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 9% is 2.3 times climatological mean ( 3.9%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 7% is 2.7 times climatological mean ( 2.4%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 11% is 2.4 times climatological mean ( 4.6%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 12% is 2.6 times climatological mean ( 4.7%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 25% is 4.7 times climatological mean ( 5.3%)

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: 5.6% 22.6% 13.5% 8.9% 6.5% 11.0% 12.3% 24.7%
Logistic: 4.6% 22.7% 8.2% 1.5% 1.2% 5.0% 7.6% 3.2%
Bayesian: 1.2% 22.6% 2.8% 0.2% 0.2% 5.7% 2.6% 10.4%
Consensus: 3.8% 22.6% 8.2% 3.6% 2.6% 7.2% 7.5% 12.7%
DTOPS: 2.0% 12.0% 3.0% 1.0% 0.0% 2.0% 3.0% 38.0%

** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL902021 INVEST 08/31/2021 12 UTC **
TIME(HR) 0-12 12-24(0-24) 24-36(0-36) 36-48(0-48)
CLIMO(%) 0 0( 0) 0( 0) 0( 0) <-- PROB BASED ON INTENSITY ONLY
PROB(%) 0 0( 0) 0( 0) 0( 0) <-- FULL MODEL PROB (RAN NORMALLY)

** DSHIPS INTENSITY FORECAST ADJUSTED RELATIVE TO ONSET OF ERC WEAKENING PHASE **
TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120 132 144 156 168
>24HR AGO (DSHIPS) 30 34 38 42 49 59 72 87 101 109 113 110 111 108 109 108 107
18HR AGO 30 29 33 37 44 54 67 82 96 104 108 105 106 103 104 103 102
12HR AGO 30 27 26 30 37 47 60 75 89 97 101 98 99 96 97 96 95
6HR AGO 30 24 21 20 27 37 50 65 79 87 91 88 89 86 87 86 85
NOW CURRENT INTENSITY < 83 KT
IN 6HR INTENSITY IN 6HR < 83 KT
IN 12HR INTENSITY IN 12HR < 83 KT

[Blown Away]

Models keep shifting SW... This is going to be a BIG hurricane...

[AutoPenalti]

For a huge hurricane to show up like that on the HWRF, it would need more than just 48 hours to consolidate.

[aspen]

12z GFS has a hurricane between 48-72hr, and that pesky blob of vorticity behind 90L is nowhere to be found so far. This might be another SW-shifted run.

[Teban54]

12z GFS has a hurricane between 48-72hr, and that pesky blob of vorticity behind 90L is nowhere to be found so far. This might be another SW-shifted run.

 https://twitter.com/webberweather/status/1432735334870228995




PS. From that loop, another observation is that Kate or whatever is left of it is trending weaker on GFS, allowing the ridge to expand westward slightly.

[cheezyWXguy]

12z gfs with another sw shift. Looks to be making a beeline for Canada. Long way out, but as of hour 222, that trough over the NE US looks to be trying to cut off as the ridge the NE builds. Not my favorite of trends.

[ColdMiser123]

12z gfs with another sw shift. Looks to be making a beeline for Canada. Long way out, but as of hour 222, that trough over the NE US looks to be trying to cut off as the ridge the NE builds. Not my favorite of trends.

The CMC illustrates why this should be watched for at least the next several days. Many solutions are still currently on the table, since this is still so far out.

[chris_fit]

Wayyyy W (inside Bermuda) on the 12 CMC (yes, I know) - and marching W/WNW

[cheezyWXguy]

12z euro is a continued shift sw, and a little stronger.

Edit: actually at hour 192 it’s in the exact same spot as the 06z

[IcyTundra]

I've been wondering where these out to sea forecasts have come from too. All I see is ridging north of 25N - I'm wondering where they are finding the weakness.

All models are showing a recurve so that's probably why. Irma and Florence were suppose to go OTS though so we will continue to keep an eye on this wave.

Just remember OTS doesnt necessarily mean no impacts, Maria was an OTS storm but blasted Dominica and here. This is north and east of maria but still, could theoretically hit us still and go OTS.

Oh trust me I don't forget about you guys in the Carribean. I am not one of this types of people that consider anything that doesn't hit the CONUS to be OTS. My definition of OTS is any storm that doesn't effect landmasses so according to my definition Maria certainly wouldn't be an OTS storm as it is the deadliest storm in the 21st century.

[weeniepatrol]

I see one member of 12z GEFS taking this into NC. Overall trend seems to be more W.

[chris_fit]

Adios says 12z Euro