CPAC: LINDA - Post-Tropical

[Sciencerocks]

[cycloneye]

Hello Linda. Will she be like the 1997 one?

EP, 12, 2021081018, , BEST, 0, 142N, 1024W, 40, 1003, TS, 34, NEQ, 80, 80, 0, 50, 1012, 180, 50, 50, 0, E, 0, , 0, 0, LINDA, M

[AnnularCane]

Hello Linda. Will she be like the 1997 one?

EP, 12, 2021081018, , BEST, 0, 142N, 1024W, 40, 1003, TS, 34, NEQ, 80, 80, 0, 50, 1012, 180, 50, 50, 0, E, 0, , 0, 0, LINDA, M

I'm saying no.

[cycloneye]

Tropical Storm Linda Discussion Number 3
NWS National Hurricane Center Miami FL EP122021
400 PM CDT Tue Aug 10 2021

A recent ASCAT-B overpass revealed tropical-storm-force winds in
both the northern and southern semicircles of the cyclone, with
believable peak winds of 38 kt. Therefore, the depression has been
upgraded to a 40-kt tropical storm.

Moderate to strong northerly shear over Linda is keeping the bulk of
the deep convection confined to the southern portion of the
cyclone's circulation, resulting in a partially exposed low-level
center. This shear is forecast to persist over the storm for the
next day or so. Therefore, despite a moist, unstable environment
with ample oceanic heat content, only slow strengthening is expected
in the short term. If the shear decreases as anticipated, a
faster rate of intensification should occur for a couple of days.
The latest NHC intensity forecast is on the low end of the guidance
through 24-36 h due to the anticipated affects of the shear, and
then trends to near the various intensity consensus values
thereafter.

The estimated motion of Linda remains 295/9 kt. The cyclone is
expected to turn westward tonight as a ridge builds to its north,
and then resume a west-northwestward motion by later this week as it
begins to move along the southwestern periphery of this ridge. This
track is roughly parallel to, but well offshore of, the southwestern
coast of Mexico over the next couple of days. Thereafter, the
depression is forecast to move away from the coast of Mexico. The
latest NHC forecast track is little changed from the previous one,
and lies near the consensus track guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 10/2100Z 14.4N 102.8W 40 KT 45 MPH
12H 11/0600Z 14.8N 104.0W 45 KT 50 MPH
24H 11/1800Z 15.0N 105.6W 50 KT 60 MPH
36H 12/0600Z 15.3N 106.9W 60 KT 70 MPH
48H 12/1800Z 16.0N 108.3W 70 KT 80 MPH
60H 13/0600Z 16.9N 110.0W 80 KT 90 MPH
72H 13/1800Z 17.8N 112.0W 85 KT 100 MPH
96H 14/1800Z 19.3N 116.0W 85 KT 100 MPH
120H 15/1800Z 20.0N 120.0W 75 KT 85 MPH

$$
Forecaster Latto

[Yellow Evan]

TXPZ23 KNES 102358
TCSENP

A. 12E (LINDA)

B. 10/2330Z

C. 14.0N

D. 102.8W

E. THREE/GOES-E

F. T2.0/2.0

G. IR/EIR/VIS

H. REMARKS...5/10 BANDING RESULTS IN A DT OF 2.5. MET IS 1.5 AND PT IS
2.0. FT IS BASED ON PT DUE TO UNCERTAINTY IN LLCC LOCATION.

I. ADDL POSITIONS

NIL


...CLARK

[Yellow Evan]

12z ECMWF. ECMWF has been remarkably consistent with this.

[aspen]

I’m extremely doubtful this becomes a hurricane. If it does, it’ll probably be weak — 70 kt max IMO.

[Yellow Evan]

18z GFS continues to make this potent, in response to relaxing the shear now as soon as 24 hours from now.

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2021 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* LINDA EP122021 08/11/21 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 50 54 58 64 71 78 83 90 90 88 85 83 79 75 71 67
V (KT) LAND 45 50 54 58 64 71 78 83 90 90 88 85 83 79 75 71 67
V (KT) LGEM 45 51 55 59 62 69 75 80 83 82 76 70 65 59 55 49 43
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 15 22 22 17 18 17 13 17 17 17 12 9 11 9 2 4 6
SHEAR ADJ (KT) 5 1 0 1 -1 0 0 0 -1 1 0 3 1 1 0 0 1
SHEAR DIR 25 43 32 35 21 7 349 27 52 56 56 71 73 94 103 136 214
SST (C) 28.8 28.8 28.8 28.6 28.5 28.5 28.7 28.4 28.1 28.0 26.9 26.3 25.4 24.9 24.4 23.6 24.2
POT. INT. (KT) 152 152 152 149 148 148 151 149 145 144 133 127 117 111 106 98 104
200 MB T (C) -52.9 -53.6 -53.9 -53.3 -53.2 -53.6 -53.0 -53.6 -52.9 -53.0 -52.4 -52.6 -52.0 -52.4 -52.1 -52.4 -51.9
200 MB VXT (C) 0.0 0.2 0.3 0.2 0.3 0.2 0.7 0.5 0.8 0.6 0.6 0.9 1.0 1.0 0.8 0.9 0.5
TH_E DEV (C) 6 4 4 6 6 5 6 5 5 4 3 3 2 1 1 1 1
700-500 MB RH 81 83 82 80 81 82 79 80 80 78 75 70 63 61 57 56 51
MODEL VTX (KT) 16 17 18 19 21 24 28 30 33 33 33 33 34 34 33 31 28
850 MB ENV VOR -46 -55 -54 -41 -28 -10 8 13 8 21 41 54 74 103 100 92 91
200 MB DIV 157 121 95 106 108 101 103 92 80 46 57 11 25 -12 10 -27 -9
700-850 TADV -5 -7 -4 -5 -4 -10 -17 -20 -1 -2 0 1 1 3 1 0 2
LAND (KM) 402 408 424 457 493 523 562 651 628 698 773 884 1053 1159 1244 1357 1529
LAT (DEG N) 14.3 14.5 14.7 14.8 14.8 15.3 16.2 17.1 18.0 18.7 19.3 19.7 19.8 xx.x xx.x xx.x xx.x
LONG(DEG W) 103.1 104.0 104.8 105.5 106.2 107.5 109.1 110.9 113.0 115.0 116.9 118.9 121.0 xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 9 8 7 7 7 8 9 11 10 10 9 10 9 8 8 9 9
HEAT CONTENT 16 16 16 14 13 14 13 10 7 7 2 0 0 0 0 0 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):300/ 9 CX,CY: -7/ 5
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 642 (MEAN=587)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 22.7 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 75.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 31.5

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. -2. -3. -4. -4.
SST POTENTIAL 1. 1. 2. 3. 6. 9. 12. 15. 16. 17. 18. 17. 16. 15. 13. 11.
VERTICAL SHEAR MAG -0. -1. -1. -1. -2. -3. -4. -6. -7. -7. -7. -6. -6. -4. -4. -3.
VERTICAL SHEAR ADJ -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0.
VERTICAL SHEAR DIR 0. 1. 1. 1. 2. 2. 2. 2. 2. 2. 1. 1. 0. 0. -0. -0.
PERSISTENCE 3. 5. 5. 5. 4. 3. 3. 2. 2. 2. 2. 2. 2. 2. 2. 2.
200/250 MB TEMP. 0. 0. -0. -0. -0. -1. -1. -1. -0. 0. 1. 3. 4. 6. 7. 8.
THETA_E EXCESS -0. -0. -1. -1. -1. -1. -2. -2. -2. -3. -4. -5. -5. -6. -8. -10.
700-500 MB RH 0. 0. 0. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2. 3. 4. 5.
MODEL VTX TENDENCY 0. 1. 2. 4. 6. 11. 16. 23. 24. 23. 22. 21. 19. 16. 13. 9.
850 MB ENV VORTICITY -0. -0. -0. -0. -0. 0. 0. 1. 1. 1. 1. 1. 1. 0. 0. -0.
200 MB DIVERGENCE 0. 1. 1. 2. 2. 3. 5. 6. 6. 6. 5. 4. 2. 1. -0. -1.
850-700 T ADVEC 0. 0. 0. 0. 0. -0. -0. -0. -0. -0. -0. -1. -1. -1. -1. -1.
ZONAL STORM MOTION 0. 0. 0. 0. 0. 0. 0. -0. -0. -0. -0. -0. -0. -0. -0. 0.
STEERING LEVEL PRES 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1. 2. 1. 1. 1. 0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 2. 2. 2. 3. 3. 3.
GOES PREDICTORS -0. -1. -1. -1. -1. -0. -0. -0. -0. -0. -0. -1. -0. 0. 0. 1.
OCEAN HEAT CONTENT -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. 0. 0. 1. 2. 3. 4.
RI POTENTIAL 1. 2. 3. 5. 7. 6. 3. 1. -1. -2. -3. -3. -3. -3. -3. -3.
------------------------------------------------------------------------------
TOTAL CHANGE 5. 9. 13. 19. 26. 33. 38. 45. 45. 43. 40. 38. 34. 30. 26. 22.

CURRENT MAX WIND (KT): 45. LAT, LON: 14.3 103.1

** 2021 E. Pacific RI INDEX EP122021 LINDA 08/11/21 00 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) : 105.6 40.5 to 149.3 0.60 4.6
12 HR PERSISTENCE (KT) : 15.0 -22.0 to 44.0 0.56 4.9
D200 (10**7s-1) : 117.4 -33.0 to 159.5 0.78 5.5
850-200 MB SHEAR (KT) : 18.9 19.6 to 1.3 0.04 0.3
MAXIMUM WIND (KT) : 45.0 22.5 to 132.0 0.64 3.4
STD DEV OF IR BR TEMP : 22.7 37.8 to 2.1 0.42 2.0
BL DRY-AIR FLUX (W/M2) : 36.2 800.8 to -82.5 0.87 -4.6
HEAT CONTENT (KJ/CM2) : 15.0 2.7 to 106.7 0.12 0.5
%area of TPW <45 mm upshear : 0.0 56.6 to 0.0 1.00 1.5
2nd PC OF IR BR TEMP : -1.0 2.2 to -2.3 0.71 0.6

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= 22% is 1.7 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 19% is 2.2 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= 12% is 2.7 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: 10.1% 21.9% 18.7% 0.0% 0.0% 0.0% 0.0% 12.5%
Logistic: 1.7% 7.3% 3.4% 1.7% 0.6% 3.1% 7.1% 7.6%
Bayesian: 0.9% 1.3% 0.5% 0.1% 0.0% 0.0% 0.1% 1.9%
Consensus: 4.2% 10.2% 7.5% 0.6% 0.2% 1.0% 2.4% 7.3%
DTOPS: 12.0% 44.0% 38.0% 27.0% 18.0% 24.0% 21.0% 12.0%

## ANNULAR HURRICANE INDEX (AHI) EP122021 LINDA 08/11/21 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) ##

[Kingarabian]

I would say the models will back off once this becomes named, but so far the models have not backed off.

Between 120-168 hours, conditions could be more favorable than what the SHIPS is showing if this can follow the Euro/CMC track.

[Sciencerocks]

[Yellow Evan]

 https://twitter.com/wxtca/status/1425293621201457152

[Yellow Evan]

222
WTPZ42 KNHC 110257
TCDEP2

Tropical Storm Linda Discussion Number 4
NWS National Hurricane Center Miami FL EP122021
1000 PM CDT Tue Aug 10 2021

Linda appears to be on an intensification trend this evening. The
low-level center, after being partially exposed to the north earlier
today, has recently become obscured by a large convective burst.
There is also some evidence of banding on the northwest side of the
center as well. The most recent 0000 UTC TAFB Dvorak estimate was
T3.0/45 kt and given the improvement in structure on satellite
imagery, the initial intensity was set to 45 kt for this advisory.

Linda appears to be starting a turn to the west, with the latest
motion now estimated at 285/8 kt. A more westward motion appears
likely in the short term as a deep-layer ridge builds in to the
north of the tropical storm. Afterwards, the guidance remains
tightly clustered on a resumption of a west-northwest track between
36-72 hours. The latest NHC track forecast is quite similar to the
previous one, except for a bit more westward motion in the
short-term. The overall track forecast remains in excellent
agreement with the track guidance consensus, and is roughly a blend
between the HFIP corrected consensus approach (HCCA) and TVCE
consensus aids.

The moderate northerly shear that has been affecting Linda today
does not appear to be hindering the storm from intensifying
currently. In fact, the ongoing convective burst may help to better
align the low and mid-level centers, which could allow for a faster
rate of intensification in the short-term. For this reason, the
intensity forecast for the next 48 hours has been increased, with
Linda now forecast to peak as a 90 knot hurricane in 60 hours.
Thereafter, while vertical wind shear and mid-level moisture are
expected to remain favorable, sea-surface temperatures will begin to
gradually decrease. Linda will also be traversing the same location
that the large wind field of Kevin is currently over, and Kevin's
large 34-kt wind radii may also lower the sea-surface temperatures
along the path of Linda. The latest NHC intensity forecast is now
around the mean of the guidance envelope through the first 48 hours,
but still remains lower than the reliable HCCA guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0300Z 14.3N 103.5W 45 KT 50 MPH
12H 11/1200Z 14.3N 104.5W 55 KT 65 MPH
24H 12/0000Z 14.5N 106.0W 65 KT 75 MPH
36H 12/1200Z 15.1N 107.2W 75 KT 85 MPH
48H 13/0000Z 16.1N 108.9W 85 KT 100 MPH
60H 13/1200Z 17.2N 110.9W 90 KT 105 MPH
72H 14/0000Z 18.0N 112.7W 90 KT 105 MPH
96H 15/0000Z 19.3N 116.5W 80 KT 90 MPH
120H 16/0000Z 19.7N 120.8W 70 KT 80 MPH

$$
Forecaster Papin/Stewart

[Kingarabian]

00z GFS now much more in line with the Euro/CMC/UKMET solutions:


So hopefully should see some pretty good ACE out of this.

[Yellow Evan]

Divergence over Linda looked quite high and may help it fight off the shear. Still, while the GFS slowly relaxes the shear over upcoming days, it’s not going to have a ton of time (probably 36-48 hours) to truly take advantage of it, which to be fair given we have an established cyclone, might be enough for a round of RI into a potent hurricane. By day 4, SST’s start to drop below 26C and that’s assuming Kevin doesn’t totally upwell them before hand. Even the southerly dip now modeled by both the GFS and ECMWF wouldn’t be enough to bring Linda back over warm SST’s.

[Kingarabian]

00z CMC big shift NE away from that westward track lol.

[Yellow Evan]

TXPZ23 KNES 110548
TCSENP

A. 12E (LINDA)

B. 11/0530Z

C. 14.1N

D. 104.1W

E. THREE/GOES-E

F. T2.5/2.5

G. IR/EIR/SWIR

H. REMARKS...6/10 BANDING RESULTS IN A DT OF 3.0. MET IS 2.0 BASED ON
NORMAL 24-HOUR DEVELOPMENT. PT IS 2.5. FT IS BASED ON PT BECAUSE THE
BANDING WAS AMBIGUOUS.

I. ADDL POSITIONS

NIL


...CLARK

[Yellow Evan]

000
WTPZ42 KNHC 110849
TCDEP2

Tropical Storm Linda Discussion Number 5
NWS National Hurricane Center Miami FL EP122021
400 AM CDT Wed Aug 11 2021

Satellite imagery suggests that Linda is still experiencing some
strong north-northeasterly vertical wind shear. The deep convection
and coldest infrared cloud tops have been displaced to the south of
the estimated low-level center for much of the overnight period,
although the position estimate is somewhat uncertain without any
recent scatterometer or microwave data. Additionally, the
upper-level outflow is sharply restricted on the upshear side of the
cyclone. Although no scatterometer passes hit the center of Linda,
ASCAT-C data across the western side of the cyclone showed at least
35 to 40-kt winds with a few marginal 45-kt vectors along the edge
of the swath. The initial intensity is held at 45 kt for this
advisory, in best agreement with a T3.0/45 kt subjective Dvorak
classification from TAFB.

Linda's estimated motion is just north of due west, or 275/8 kt.
This westward motion is expected to continue through tonight as the
cyclone is steered by a building ridge to its north. Then, the track
guidance agrees that Linda will turn west-northwestward on Thursday
and maintain this general heading through the weekend, keeping the
system well offshore of southwestern Mexico. The updated NHC track
forecast has been adjusted a little south of the previous one based
on the latest TVCE and HCCA consensus aids.

The short-term intensity forecast is a bit tricky, since it is
uncertain how the persistent deep convection has changed the
structure of the cyclone. Although the moderate to strong shear is
expected to persist for the next couple of days, very warm SSTs and
a moist, unstable environment should allow for at least some
strengthening. Linda is still forecast to become a hurricane later
this week. The wind shear is expected to diminish on Friday and
Saturday, while the thermodynamic environment remains favorable for
some continued development. Thus, Linda could continue strengthening
into the weekend before it reaches cooler SSTs and begins a gradual
weakening trend near the end of the period. Overall, the NHC
intensity forecast is a bit weaker than the previous one and shows a
slightly slower intensification rate in the near-term, closer to the
IVCN consensus aid.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0900Z 14.2N 104.4W 45 KT 50 MPH
12H 11/1800Z 14.2N 105.4W 55 KT 65 MPH
24H 12/0600Z 14.6N 106.8W 60 KT 70 MPH
36H 12/1800Z 15.3N 108.3W 65 KT 75 MPH
48H 13/0600Z 16.3N 110.2W 75 KT 85 MPH
60H 13/1800Z 17.3N 112.2W 80 KT 90 MPH
72H 14/0600Z 18.1N 114.3W 85 KT 100 MPH
96H 15/0600Z 19.2N 118.0W 80 KT 90 MPH
120H 16/0600Z 19.5N 122.0W 70 KT 80 MPH

$$
Forecaster Reinhart/Pasch

[Yellow Evan]

TXPZ23 KNES 111215
TCSENP

A. 12E (LINDA)

B. 11/1130Z

C. 13.9N

D. 105.0W

E. THREE/GOES-E

F. T3.0/3.0

G. IR/EIR/VIS/GMI

H. REMARKS...SYSTEM HAS 6/10 BANDING RESULTING IN A DT OF 3.0. THE 24
HR DEVELOPING TREND RESULTS IN DEVELOPING. MET IS 2.5 AND PT 3.0. FT IS
BASED ON PT DUE TO BANDING FEATURES NOT BEING CLEAR CUT.

I. ADDL POSITIONS

11/0800Z 14.2N 104.8W GMI


...PATEL

[Sciencerocks]