EPAC: CRISTINA - Post-Tropical

[Yellow Evan]

I disagree. It's made a pretty quick transition from banding to CDO dominant.

[aspen]

I disagree. It's made a pretty quick transition from banding to CDO dominant.

When I woke up and checked about an hour and a half ago, the circulation was halfway exposed.

[Yellow Evan]

I disagree. It's made a pretty quick transition from banding to CDO dominant.

When I woke up and checked about an hour and a half ago, the circulation was halfway exposed.

Given the 8z microwave, I don't think that's actually the center. Center seems to be at around 11.8N 112.7W.

[aspen]

Cristina wasted no time forming, but now it’s taking its sweet time becoming anything significant. Still hasn’t even surpassed 35 kt.

[aspen]

The center of circulation is indeed partially exposed, sticking out from the NE part of the growing convective blob. I think dry air disrupted the core and now it’s trying to reform with that convective band to the NE.

https://www.tropicaltidbits.com/sat/sat ... roduct=vis

[Yellow Evan]

It’s not really exposed but it’s still looking really weird at the moment. Hopefully it’ll make progress today.

[aspen]

It’s not really exposed but it’s still looking really weird at the moment. Hopefully it’ll make progress today.

In the tropical storm discussion, the NHC mentions that the bit of shear and dry air Cristina is facing should not be a long-lasting problem, and the environment for the next 1-2 days is still expected to be very favorable.

[Yellow Evan]

000
WTPZ45 KNHC 071448
TCDEP5

Tropical Storm Cristina Discussion Number 4
NWS National Hurricane Center Miami FL EP052020
1000 AM CDT Tue Jul 07 2020

Early morning microwave and first-light visible imagery revealed
that the center of Cristina was located well to the east-northeast
of previous estimates. The center is now located near the end of
a long curved band that goes around portions of its western
semicircle. The center position relative to the convection suggests
that at least some northeasterly shear is negatively affecting the
organization of Cristina and it may not be well vertically aligned
yet. Various satellite intensity estimates have increased since the
last advisory, but were also based in part on an assumption that the
center of Cristina was located farther west, so the initial wind
speed has been conservatively held at 35 kt for now.

The new NHC track forecast has been adjusted a fair amount to the
east of the previous one, mainly due to the updated initial
position. That said, the overall thinking behind the forecast has
not changed. A mid-level ridge centered over the southwestern U.S.
should steer Cristina on a general west-northwestward path through
the end of the week. The official forecast is very near the latest
multi-model consensus at all forecast times.

The shear and some nearby dry air that appear to have
inhibited Cristina's organization so far are not expected to
persist as negative factors for much longer. All of the models
still forecast strengthening, and given the very favorable
environment that the cyclone will encounter in a day or two,
a period of rapid intensification at some point would not be
surprising. The NHC forecast remains near the high end of the
guidance envelope, near the HFIP Corrected Consensus. Cristina
is forecast to reach cooler waters that will likely lead to
weakening over the weekend.


FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 12.2N 102.8W 35 KT 40 MPH
12H 08/0000Z 12.9N 104.5W 45 KT 50 MPH
24H 08/1200Z 13.9N 106.5W 55 KT 65 MPH
36H 09/0000Z 15.0N 108.4W 65 KT 75 MPH
48H 09/1200Z 15.9N 110.2W 80 KT 90 MPH
60H 10/0000Z 16.9N 112.0W 90 KT 105 MPH
72H 10/1200Z 17.9N 113.8W 90 KT 105 MPH
96H 11/1200Z 19.5N 118.5W 75 KT 85 MPH
120H 12/1200Z 21.0N 123.5W 55 KT 65 MPH

$$
Forecaster Zelinsky

[Yellow Evan]

Not looking great this morning. Has somewhat of that mid level shear look and I pull up the map and guess what.

[aspen]

Not looking great this morning. Has somewhat of that mid level shear look and I pull up the map and guess what.

https://i.imgur.com/sL86LKZ.gif

Looks like it’s heading into a pocket of <5 kt of mid-level shear, and since convection is spreading back over the CoC, I think we should see recovery begin within 12 hours.

[Yellow Evan]

07/1730 UTC 12.7N 103.1W T2.5/2.5 CRISTINA -- East Pacific

[cycloneye]

Up to 40kts.

05E CRISTINA 200707 1800 12.7N 103.3W EPAC 40 1003

[Kingarabian]

Still has 72 hours left of acceptable environmental conditions.

[aspen]

Still has 72 hours left of acceptable environmental conditions.

If it somehow does not attempt RI during its three full days within a favorable environment, I will completely lose faith in the EPac until September.

[Yellow Evan]

I mean it's possible it was stronger earlier but idk how one can with a straight face say this is strengthening now. It's weakening.

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2020 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* CRISTINA EP052020 07/07/20 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 40 43 46 50 56 66 78 85 87 81 80 73 66 57 48 40 34
V (KT) LAND 40 43 46 50 56 66 78 85 87 81 80 73 66 57 48 40 34
V (KT) LGEM 40 43 45 48 51 58 66 73 75 71 63 55 47 41 34 29 24
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 6 9 12 11 9 6 7 14 15 11 4 3 6 8 14 10 13
SHEAR ADJ (KT) 3 4 3 3 0 -1 0 -3 -5 -3 -1 -3 -2 -1 -1 0 -3
SHEAR DIR 18 4 4 354 347 42 74 56 32 51 23 340 287 277 267 287 287
SST (C) 29.5 29.6 29.5 29.2 28.4 28.2 28.1 27.3 26.8 24.7 24.4 23.2 22.7 22.2 22.3 22.0 22.4
POT. INT. (KT) 160 161 160 157 149 146 145 137 132 111 108 95 90 85 86 83 87
200 MB T (C) -53.0 -52.6 -52.8 -53.0 -52.7 -52.8 -52.5 -52.4 -52.2 -52.2 -52.0 -51.9 -52.0 -51.8 -52.0 -51.9 -52.0
200 MB VXT (C) 0.2 0.2 0.3 0.3 0.3 0.3 0.5 0.9 0.9 1.0 0.5 0.9 0.7 0.7 0.4 0.4 0.6
TH_E DEV (C) 6 7 6 7 7 6 5 4 2 1 0 0 0 0 0 0 0
700-500 MB RH 77 77 77 79 79 81 80 80 79 79 74 68 63 60 56 48 39
MODEL VTX (KT) 16 17 18 18 20 20 25 28 30 28 30 28 27 24 21 18 15
850 MB ENV VOR 6 -1 -9 -2 7 13 30 27 40 62 80 109 109 117 118 100 91
200 MB DIV 57 92 108 103 126 125 100 73 34 39 44 23 1 -4 -20 -30 -16
700-850 TADV -2 -3 -6 -5 -5 -6 1 -5 -4 -5 -1 0 2 0 -2 -1 -2
LAND (KM) 568 562 557 559 571 598 691 643 684 780 922 1058 1188 1371 1596 1762 1902
LAT (DEG N) 12.7 13.2 13.6 14.2 14.7 15.7 16.6 17.7 18.5 19.3 20.1 20.9 21.5 xx.x xx.x xx.x xx.x
LONG(DEG W) 103.3 104.3 105.3 106.3 107.3 109.1 110.9 112.7 114.6 117.0 119.7 122.2 124.5 xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 11 11 11 11 10 10 10 10 11 13 13 12 12 12 13 13 12
HEAT CONTENT 50 43 32 23 14 11 8 4 3 0 0 0 0 0 0 0 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):305/ 11 CX,CY: -8/ 6
T-12 MAX WIND: 35 PRESSURE OF STEERING LEVEL (MB): 631 (MEAN=587)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 24.2 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 80.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 35.9

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. 3. 6. 10. 13. 16. 17. 18. 17. 15. 13. 10. 7. 5.
VERTICAL SHEAR MAG 0. 1. 1. 2. 3. 4. 4. 2. 1. 2. 3. 4. 5. 4. 3. 3.
VERTICAL SHEAR ADJ -0. -1. -1. -1. -1. -0. -0. 0. 0. 0. -0. -0. -0. -0. 0. 0.
VERTICAL SHEAR DIR 0. 0. 0. 0. 1. 2. 2. 2. 2. 2. 1. 1. 1. 0. 0. 0.
PERSISTENCE 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1.
200/250 MB TEMP. 0. -0. -0. -0. -1. -1. -1. -1. -0. 0. 1. 3. 4. 4. 5. 5.
THETA_E EXCESS -0. 0. 0. 0. 0. -0. -1. -2. -3. -5. -6. -7. -8. -9. -10. -12.
700-500 MB RH 0. 0. 0. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2. 2. 2. 3.
MODEL VTX TENDENCY 0. 1. 1. 2. 3. 9. 15. 19. 17. 19. 15. 12. 8. 4. 1. -1.
850 MB ENV VORTICITY -0. -0. -0. -0. -0. 0. 0. 0. 0. 0. -0. -0. -1. -1. -1. -1.
200 MB DIVERGENCE 0. 0. 1. 1. 2. 3. 4. 5. 5. 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. -1.
ZONAL STORM MOTION 0. 0. 0. 0. 0. 1. 1. 0. 0. 0. 0. 0. 0. 0. 0. -0.
STEERING LEVEL PRES 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 0.
DAYS FROM CLIM. PEAK -0. -0. -0. -0. -0. -0. -0. -1. -1. -2. -2. -2. -2. -3. -3. -3.
GOES PREDICTORS -0. -0. -1. -1. -0. 0. 0. 0. 0. 1. 0. 0. 0. 1. 1. 1.
OCEAN HEAT CONTENT -0. 0. 0. 0. 0. 0. 0. -0. -0. -0. -0. 0. 0. 1. 2. 3.
RI POTENTIAL 1. 2. 4. 6. 9. 8. 5. 1. -1. -2. -4. -4. -4. -4. -4. -4.
------------------------------------------------------------------------------
TOTAL CHANGE 3. 6. 10. 16. 26. 38. 45. 47. 41. 40. 33. 26. 17. 8. -0. -6.

CURRENT MAX WIND (KT): 40. LAT, LON: 12.7 103.3

** 2020 E. Pacific RI INDEX EP052020 CRISTINA 07/07/20 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) : 117.5 40.5 to 149.3 0.71 7.2
12 HR PERSISTENCE (KT) : 5.0 -22.0 to 44.0 0.41 4.9
850-200 MB SHEAR (KT) : 9.6 19.6 to 1.4 0.55 5.1
D200 (10**7s-1) : 97.2 -33.0 to 160.6 0.67 6.5
MAXIMUM WIND (KT) : 40.0 22.5 to 132.0 0.50 3.6
STD DEV OF IR BR TEMP : 24.2 37.8 to 2.1 0.38 2.3
HEAT CONTENT (KJ/CM2) : 32.4 2.7 to 106.7 0.29 1.6
BL DRY-AIR FLUX (W/M2) : 50.2 800.8 to -82.5 0.85 -6.4
%area of TPW <45 mm upshear : 0.0 56.6 to 0.0 1.00 2.5
2nd PC OF IR BR TEMP : -0.7 2.2 to -1.9 0.71 0.5

SHIPS Prob RI for 20kt/ 12hr RI threshold= 15% is 2.3 times climatological mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 29% is 2.3 times climatological mean (12.6%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 28% is 3.2 times climatological mean ( 8.6%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 20% is 3.2 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= 25% is 3.7 times climatological mean ( 6.7%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 32% is 5.5 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: 14.6% 29.3% 27.9% 19.7% 0.0% 25.0% 32.2% 12.5%
Logistic: 6.3% 33.7% 19.7% 11.6% 2.4% 35.0% 40.8% 13.1%
Bayesian: 5.5% 34.2% 36.8% 12.7% 1.6% 15.9% 7.7% 9.4%
Consensus: 8.8% 32.4% 28.1% 14.7% 1.3% 25.3% 26.9% 11.6%
DTOPS: 4.0% 29.0% 19.0% 14.0% 9.0% 24.0% 26.0% 24.0%

## ANNULAR HURRICANE INDEX (AHI) EP052020 CRISTINA 07/07/20 18 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]

Still has 72 hours left of acceptable environmental conditions.

If it somehow does not attempt RI during its three full days within a favorable environment, I will completely lose faith in the EPac until September.

We have to understand with a weak La Nina possibly coming on, there will likely be no September for the EPAC this season.

[cycloneye]

Tropical Storm Cristina Discussion Number 5
NWS National Hurricane Center Miami FL EP052020
400 PM CDT Tue Jul 07 2020

Cristina is still being affected by some northeasterly vertical wind
shear as visible satellite imagery shows that the center is located
near the northeastern edge of the large curved convective band. The
various subjective and objective satellite intensity estimates range
from 35 to 45 kt, and a recent ASCAT overpass revealed a small area
of 35-40 kt wind vectors near the center. Based on these data, the
initial intensity is set at 40 kt. The moderate vertical wind shear
over the system is forecast to abate over the next 12-24 hours.
This, along with SSTs of 28-29C, should allow for strengthening and
Cristina is still forecast to become a hurricane in a day or two.
Although Cristina has not strengthened as much as anticipated over
the past 24 hours, with the more favorable atmospheric conditions
anticipated beginning Wednesday, a period of steady to rapid
strengthening is still possible. The latest intensity guidance
shows a slightly lower peak wind speed than before, so the new NHC
intensity forecast has been nudged in that direction. After 72
hours, Cristina will be moving over cooler waters and steady
weakening is expected later in the period.

Satellite fixes show that Cristina is moving west-northwestward or
305/11 kt. There has been no significant change to the track foreast
reasoning. Cristina should continue on a west-northwestward
heading over the next several days to the south of a large mid-level
ridge over the southwestern United States. The overall track
guidance envelop has shifted slightly northward, so the NHC track
forecast has been adjusted accordingly. The new track forecast lies
between the previous official foreast and the most recent consensus
aids.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 13.0N 103.8W 40 KT 45 MPH
12H 08/0600Z 13.8N 105.3W 45 KT 50 MPH
24H 08/1800Z 15.0N 107.2W 55 KT 65 MPH
36H 09/0600Z 16.1N 109.2W 65 KT 75 MPH
48H 09/1800Z 17.0N 110.9W 75 KT 85 MPH
60H 10/0600Z 18.0N 112.7W 85 KT 100 MPH
72H 10/1800Z 19.0N 114.9W 85 KT 100 MPH
96H 11/1800Z 20.5N 119.8W 70 KT 80 MPH
120H 12/1800Z 21.8N 125.0W 50 KT 60 MPH

$$
Forecaster Brown

[Yellow Evan]

Still has 72 hours left of acceptable environmental conditions.

If it somehow does not attempt RI during its three full days within a favorable environment, I will completely lose faith in the EPac until September.

We have to understand with a weak La Nina possibly coming on, there will likely be no September for the EPAC this season.

That's a bit too far honestly. If anything the biggest hindrance will be the insane activity we will see in the Atlantic.

[aspen]

I’m now doubtful that Cristina will surpass low-end Cat 2 intensity. I’m going to revise my predicted max intensity to 85/90 kt.