WPAC: DORA - Post-Tropical - Discussion

[Yellow Evan]

TXPZ21 KNES 010629
TCSENP

A. 05E (NONAME)

B. 01/0600Z

C. 15.8N

D. 106.4W

E. THREE/GOES-W

F. T2.5/2.5

G. IR/EIR/SWIR

H. REMARKS...LOW CONFIDENCE IN CENTER LOCATION. SYSTEM IS CHARACTERIZED
BY A CENTRAL COLD COVER (CCC) WHICH DOES NOT ALLOW FOR A DT. MET IS 2.0
BASED ON DEVELOPING TREND. PT IS 2.5. THE FT IS BASED ON THE PT BECAUSE
AN ADJUSTMENT TO THE MET WAS MADE.

I. ADDL POSITIONS

NIL


...TURK

[Extratropical94]

EP, 05, 2023080106, , BEST, 0, 158N, 1064W, 35, 1006, TS

We'll have Dora in an hour.

[Extratropical94]

Dora has started exploring

Tropical Storm Dora Advisory Number 3
NWS National Hurricane Center Miami FL EP052023
300 AM MDT Tue Aug 01 2023

...DEPRESSION STRENGTHENS INTO TROPICAL STORM DORA...


SUMMARY OF 300 AM MDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...16.0N 107.1W
ABOUT 275 MI...445 KM SW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES

Tropical Storm Dora Discussion Number 3
NWS National Hurricane Center Miami FL EP052023
300 AM MDT Tue Aug 01 2023

Deep convection has increased near the estimated center of the
tropical cyclone, but convective banding features are not yet well
defined. Subjective Dvorak intensity estimates from both TAFB and
SAB are now at 35 kt and data from a recent scatterometer overpass
also supports tropical storm strength. Thus the system is being
named, making it the fourth tropical storm of this rather
slow-starting eastern North Pacific hurricane season. Dora is a
fairly compact system, with tropical-storm-force winds
extending 40 n mi or less from the center.

The storm's motion is a slightly faster 290/14 kt. The mid-level
subtropical ridge that is currently to the north of Dora is
forecast by the global models to build westward over the next
several days. This should cause the tropical storm or hurricane to
turn westward to west-southwestward during the next 24 to 60 hours.
Later in the forecast period, Dora should move generally westward
on the south side of the subtropical high. The official forecast
is slightly faster than the previous one but not quite as fast as
the latest corrected consensus, HCCA, track guidance.

Dora is expected to be in an atmospheric and oceanic environment
that will be quite conducive for intensification during the next 72
hours or so. A large upper-tropospheric anticyclone should
dominate the area, leading to low vertical shear. This, along
with SSTs of 28-29 deg C, and a fairly moist mid-level air mass
should result in significant strengthening of the cyclone. The
SHIPS Rapid Intensification (RI) guidance shows a greater than
normal likelihood of RI, but it is difficult to specify when this
may occur. The official forecast calls, perhaps conservatively,
for Dora to approach major hurricane status later in the week.
This prediction is a blend of the corrected and simple intensity
model consensus guidance, IVCN and HCCA. The regional hurricane
models, HAFS and HWRF, indicate that Dora could be stronger than
shown here.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 16.0N 107.1W 35 KT 40 MPH
12H 01/1800Z 16.2N 109.2W 45 KT 50 MPH
24H 02/0600Z 16.1N 112.0W 55 KT 65 MPH
36H 02/1800Z 15.8N 114.7W 70 KT 80 MPH
48H 03/0600Z 15.3N 117.6W 80 KT 90 MPH
60H 03/1800Z 14.7N 120.6W 90 KT 105 MPH
72H 04/0600Z 14.2N 123.7W 95 KT 110 MPH
96H 05/0600Z 13.3N 129.8W 90 KT 105 MPH
120H 06/0600Z 13.0N 135.5W 80 KT 90 MPH

[Extratropical94]

NHC forecast calls for about 12 ACE units over the next 5 days.

[jconsor]

Stark divergence between global models (aside from GFS/GEFS), which are rather tepid with Dora, and mesoscale hurricane models like HAFS, HWRF and COAMPS-TC, which generally make this a major hurricane.

ICON, UKMET and CMC don't deepen this beyond ~1005 mb, a weak tropical storm. UKMET and CMC have shown a weak bias on TCs this year (and UKMET in past several years as well),. However, the fact that they barely deepen Dora (and have been consistent on this) is interesting IMHO. ICON has, in my experience, been a valuable piece of guidance, so the fact that it has consistently not deepened Dora much and is trending north on her track is also interesting.

Based on minimum pressure, only ~35% of EPS members make this a hurricane at any point in the next five days! If you based on max winds, only ~20-25% do. A subtle northward trend in the past several runs (closer to dry, stable air and cooler SSTs to the north) may be a large part of the reason. This northward trend is due to a weaker ridge to the NE of Dora and a stronger trough to its NW near Hawaii.

[Yellow Evan]

ECMWF literally initialized at 1010mbar with a single closed isobar on TT. Not sure how much weight can be placed towards a model with that input. It also wouldn’t be the first time the ECMWF badly underinitialized and subsequently greatly underpredicted a small system like this.

[Yellow Evan]

Hurricane soon with that microwave presentation if it keeps it up.

[cycloneye]

Looks ready to be a hurricane sooner than what NHC has. I think we will have great photogenic images of this small cyclone in the next few days.

[Yellow Evan]

TXPZ21 KNES 011223
TCSENP

A. 05E (DORA)

B. 01/1201Z

C. 16.1N

D. 107.8W

E. THREE/GOES-E

F. T3.0/3.0

G. IR/EIR/SWIR

H. REMARKS...6/10 BANDING YIELDS A DT OF 3.0. THE MET IS 2.0. THE PT
IS 2.5. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...GATLING

[cycloneye]

Up to 45kt.

EP, 05, 2023080112, , BEST, 0, 160N, 1079W, 45, 1002, TS

[Yellow Evan]

EP, 05, 202308011200, 10, DVTS, CI, , 1610N, 10770W, , 3, 55, 2, 994, 2, DVRK, , , , , , , , , , , , , , E, TAFB, JL, I, 5, 3535 /////, , , GOES16, CSC, T, System has a classic 3.5 appearance with white (or colder)

[Sciencerocks]

[Yellow Evan]

* GFS version *
* EAST PACIFIC 2023 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* DORA EP052023 08/01/23 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 45 51 56 61 65 75 83 89 90 92 94 93 92 94 93 92 89
V (KT) LAND 45 51 56 61 65 75 83 89 90 92 94 93 92 94 93 92 89
V (KT) LGEM 45 52 58 63 68 77 85 91 95 96 99 99 97 93 89 85 79
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 9 7 5 2 2 5 11 10 10 9 5 3 2 4 3 2 3
SHEAR ADJ (KT) -4 -6 -4 4 5 -2 -3 -5 -3 -1 0 7 5 5 3 3 3
SHEAR DIR 107 144 178 329 6 44 68 81 72 75 125 173 225 100 112 51 22
SST (C) 29.7 29.9 29.7 29.4 29.2 29.1 28.7 27.5 27.5 26.9 27.3 26.8 26.6 27.1 26.7 27.0 26.6
POT. INT. (KT) 164 166 163 160 158 157 153 141 141 135 138 133 131 136 132 135 130
200 MB T (C) -51.2 -51.1 -50.9 -51.0 -51.1 -50.8 -51.2 -50.6 -51.3 -51.3 -51.9 -51.6 -52.3 -51.9 -52.2 -51.9 -52.3
200 MB VXT (C) 0.2 0.2 0.3 0.4 0.5 0.4 0.6 0.6 0.8 0.9 0.8 0.4 0.5 0.3 0.1 0.0 0.0
TH_E DEV (C) 8 8 8 8 7 6 6 5 5 5 4 5 4 4 4 4 4
700-500 MB RH 67 63 60 60 60 61 60 60 60 59 62 62 64 58 53 46 46
MODEL VTX (KT) 9 10 11 12 12 14 16 17 17 19 20 19 19 20 20 17 14
850 MB ENV VOR 4 3 0 6 8 19 26 52 66 78 81 66 76 85 94 85 77
200 MB DIV 7 17 11 -2 -12 13 -14 12 -23 -2 -7 -4 7 18 0 -5 -8
700-850 TADV 1 3 -1 -7 -2 0 0 0 -2 -4 0 1 -6 -4 -2 0 0
LAND (KM) 485 594 714 801 861 1055 1320 1574 1846 2120 2362 2317 2031 1756 1512 1285 1076
LAT (DEG N) 16.0 16.1 16.1 16.0 15.9 15.5 14.9 14.4 13.9 13.4 13.1 12.9 13.0 xx.x xx.x xx.x xx.x
LONG(DEG W) 107.9 109.4 110.8 112.2 113.5 116.3 119.3 122.3 125.4 128.5 131.4 134.2 137.0 xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 14 14 13 13 13 14 15 15 15 15 14 14 14 13 13 12 12
HEAT CONTENT 31 30 29 23 18 17 17 6 11 2 4 6 4 16 2 5 3

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):280/ 14 CX,CY: -13/ 2
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 418 (MEAN=588)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 14.9 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 84.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 34.8

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. 1. 1. 1. 1. 2. 2. 1. 1. -0. -1. -1. -2. -3. -3. -4.
SST POTENTIAL 1. 1. 3. 4. 8. 13. 18. 23. 25. 28. 31. 32. 33. 33. 34. 33.
VERTICAL SHEAR MAG 0. 1. 2. 3. 5. 5. 6. 6. 6. 6. 8. 9. 11. 12. 13. 15.
VERTICAL SHEAR ADJ 0. 1. 1. 1. 1. 1. 2. 2. 1. 1. 0. 0. 0. 0. 0. -0.
VERTICAL SHEAR DIR 0. -0. -0. -0. 1. 2. 3. 5. 6. 6. 5. 3. 2. 2. 1. 0.
PERSISTENCE 3. 4. 5. 5. 4. 4. 3. 3. 2. 2. 2. 2. 2. 2. 2. 2.
200/250 MB TEMP. -0. -0. -1. -1. -1. -1. -1. -1. -1. -0. 0. 1. 2. 2. 2. 1.
THETA_E EXCESS 0. 0. 1. 1. 1. 1. 1. 1. 0. -0. -1. -1. -1. -1. -1. -1.
700-500 MB RH 0. 0. 0. -0. -0. -0. -0. -0. -0. -0. 0. 0. 0. 0. 0. -0.
MODEL VTX TENDENCY 0. 1. 1. 2. 4. 6. 9. 10. 12. 14. 12. 11. 11. 9. 6. 4.
850 MB ENV VORTICITY -0. -0. -0. -0. -0. -0. 0. 0. -0. -0. -0. -0. -0. -0. -0. -0.
200 MB DIVERGENCE -0. -0. -0. -0. -0. -1. -1. -2. -3. -3. -2. -2. -1. 0. 0. 1.
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. 0. 0. -0. -0. -0. -1. -0. -1. -1. -2. -2.
STEERING LEVEL PRES -0. -0. -1. -1. -2. -2. -3. -3. -3. -4. -4. -5. -4. -3. -3. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1.
GOES PREDICTORS 0. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1.
OCEAN HEAT CONTENT -0. -0. -0. -0. -0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1.
RI POTENTIAL 1. 2. 4. 5. 8. 7. 4. 1. -1. -2. -4. -4. -4. -4. -4. -4.
--------------------------------------------------------------------------------------------
TOTAL CHANGE 6. 11. 16. 20. 30. 38. 44. 45. 47. 49. 48. 47. 49. 48. 47. 44.

CURRENT MAX WIND (KT): 45. LAT, LON: 16.0 107.9

** 2023 E. PACIFIC RI INDEX EP052023 DORA 08/01/23 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
POT = MPI-VMAX (KT) : 117.1 36.9 to 148.5 0.72 13.4
12 HR PERSISTENCE (KT) : 15.0 -22.0 to 44.0 0.56 9.0
MULTI-LAYER SHEAR (KT) : 14.7 30.9 to 7.7 0.70 8.9
BL DRY-AIR FLUX (W/M2) : 222.6 816.2 to -81.4 0.66 -9.5
D200 (10**7s-1) : 4.2 -33.0 to 159.5 0.19 2.2
MAXIMUM WIND (KT) : 45.0 22.5 to 132.0 0.64 7.0
STD DEV OF IR BR TEMP : 14.9 37.8 to 2.1 0.64 5.8
HEAT CONTENT (KJ/CM2) : 26.2 2.7 to 103.4 0.23 1.3
%area of TPW <45 mm upshear : 5.6 49.8 to 0.0 0.89 3.1
2nd PC OF IR BR TEMP : -0.5 2.2 to -2.3 0.61 0.1

SHIPS Prob RI for 20kt/ 12hr RI threshold= 30% is 4.7 times climatological mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 49% is 3.9 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 41% is 4.8 times climatological mean ( 8.6%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 34% is 5.5 times climatological mean ( 6.2%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 20% is 4.8 times climatological mean ( 4.2%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 43% is 6.4 times climatological mean ( 6.7%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 53% is 8.9 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 31% is 6.7 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: 29.8% 49.2% 41.2% 34.4% 20.2% 42.6% 52.8% 31.4%
Logistic: 23.0% 51.0% 37.2% 23.2% 12.9% 15.0% 5.0% 11.3%
Bayesian: 4.8% 30.9% 2.7% 0.8% 3.8% 3.2% 1.9% 0.0%
Consensus: 19.2% 43.7% 27.0% 19.5% 12.3% 20.3% 19.9% 14.2%
DTOPS: 26.0% 72.0% 59.0% 45.0% 35.0% 70.0% 73.0% 43.0%

## ANNULAR HURRICANE INDEX (AHI) EP052023 DORA 08/01/23 12 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]

NHC will bump to cat 3 at next advisory.

[InfernoFlameCat]

I think this gets to high end cat 3. The ceiling calls for higher, but it is a small cyclone and could easily lose strength when facing some mid level shear.

[cycloneye]

Dora is wasting no time.The sky is the limit.

Tropical Storm Dora Discussion Number 4
NWS National Hurricane Center Miami FL EP052023
900 AM MDT Tue Aug 01 2023

Dora is wasting no time getting better organized this morning and
may be in the initial stages of rapid intensification. The storm's
structure has improved, with a prominent cold curved band seen on
its northern semicircle rotating into a developing central dense
overcast near the estimated center is. An earlier F-18 SSMIS pass at
1058 UTC also suggested a formative inner core was taking shape.
Subjective intensity estimates from TAFB and SAB were T3.5/55 kt and
T3.0/45 kt respectively. The objective intensity estimates currently
have a large spread from 36-56 kt, depending on exactly where the
center is. Dora's initial intensity for this advisory is on the
higher side of those estimates at 50 kt.

Dora is moving just north of due west this morning at 280/14 kt. The
track philosophy has not changed much this cycle, with a large
mid-level ridge expected to build westward to the north and ahead of
Dora. This evolution should result in Dora maintaining its forward
motion as it begins a gradual turn to the west-southwest over the
next 2-3 days. The track guidance is ever so slightly faster than
the previous cycle, and the official forecast is a bit faster than
before, following a blend of the latest HCCA and TVCE consensus
aids.

All systems appear go for Dora to intensify a substantial amount
over the next several days. GFS SHIPS-derived shear is under 10 kt
for the entire forecast period, and sea-surface temperatures (SSTs)
also remain above 28 C for at least the next 48 h. Dora is a small
tropical cyclone, which can be prone to rapid intensity changes. The
only factor that could prevent robust intensification in the short
term is dry air entrainment disrupting the formative inner core.
With that said, rapid intensification (RI) indices have sharply
increased, with DTOPS now indicating a 70 percent chance of RI over
the next 24 hours. Given this guidance, the official forecast will
now explicitly show RI over the next 24-36 h, with a higher peak
intensity, taking Dora to major hurricane intensity in the next 48
hours. This part of the intensity forecast is in best agreement with
the latest HCCA intensity aid, but remains lower than the latest
HAFS-A/B runs. Towards the end of the forecast period, Dora will
begin exploring cooler 26-27 C SSTs along its track, which may
initiate some gradual weakening.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 16.1N 108.6W 50 KT 60 MPH
12H 02/0000Z 16.2N 110.8W 65 KT 75 MPH
24H 02/1200Z 16.0N 113.6W 80 KT 90 MPH
36H 03/0000Z 15.6N 116.4W 95 KT 110 MPH
48H 03/1200Z 15.0N 119.3W 105 KT 120 MPH
60H 04/0000Z 14.5N 122.3W 105 KT 120 MPH
72H 04/1200Z 13.9N 125.3W 105 KT 120 MPH
96H 05/1200Z 13.1N 131.6W 100 KT 115 MPH
120H 06/1200Z 12.5N 137.5W 90 KT 105 MPH

$$
Forecaster Papin

[WiscoWx02]

NHC snuck a “Dora the Explorer” reference at the end of their latest discussion when referencing colder waters at the end of the forecast period Curious to see if the dreaded mid level shear makes an appearance here

[Kingarabian]

Its looking great.

The models always under forecast the intensity of most EPAC systems. This issue is more glaring during El Nino/warm neutral years. That being said the quality so far has been lacking so I give them some weight, especially when this begins to near 120W. But this looks like it's about to take off.

[Cyclenall]

NHC snuck a “Dora the Explorer” reference at the end of their latest discussion when referencing colder waters at the end of the forecast period Curious to see if the dreaded mid level shear makes an appearance here

I didn't catch that one, I did for a split sec notice the unusual adj "exploring" there. When is the dreaded pinhole eye going to present?

Its been a while since there was a wsw bending track forecast, I find those interesting. Remember "For goodness sakes Hector, lose some latitude!"

[Kingarabian]

Clear cut 3.5 and borderline 4 0. Very close to hurricane status.