EPAC: BLANCA - Post-Tropical

[Kingarabian]

[Yellow Evan]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* BLANCA EP022015 06/04/15 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 85 81 81 85 88 91 88 73 55 34 DIS DIS DIS
V (KT) LAND 85 81 81 85 88 91 88 73 55 34 DIS DIS DIS
V (KT) LGE mod 85 79 76 76 77 79 77 69 58 47 36 28 20
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 7 6 5 5 7 9 9 22 22 23 14 14 18
SHEAR ADJ (KT) 1 4 7 12 10 8 13 6 2 6 4 9 5
SHEAR DIR 131 109 86 112 110 128 129 121 130 151 179 166 178
SST (C) 30.3 30.2 30.1 29.9 29.5 28.6 27.4 26.2 25.2 23.7 22.2 21.5 20.6
POT. INT. (KT) 166 166 166 164 160 150 137 124 114 99 83 75 65
200 MB T (C) -51.3 -51.0 -51.4 -51.2 -50.7 -50.9 -50.5 -50.8 -51.0 -51.2 -51.5 -51.2 -51.2
TH_E DEV (C) 8 8 8 8 8 7 7 6 6 4 3 2 2
700-500 MB RH 78 77 76 75 73 65 60 55 52 48 45 39 35
MODEL VTX (KT) 36 36 38 40 40 40 40 35 28 21 15 7 6
850 MB ENV VOR 74 79 82 84 91 73 63 70 62 69 38 25 6
200 MB DIV 122 115 77 90 108 46 28 -5 -45 -27 2 -4 6
700-850 TADV 0 0 -1 -1 -1 0 1 1 1 0 -2 -2 -1
LAND (KM) 655 616 585 563 542 509 488 400 269 128 47 40 55
LAT (DEG N) 12.5 13.1 13.7 14.4 15.1 16.6 18.0 19.3 20.5 22.1 24.0 25.4 26.2
LONG(DEG W) 105.0 105.5 106.0 106.8 107.5 108.8 109.6 110.1 110.4 110.9 111.6 112.5 113.4
STM SPEED (KT) 5 8 9 10 10 8 8 6 7 9 9 7 5
HEAT CONTENT 95 92 89 57 28 22 6 1 0 0 0 0 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):325/ 2 CX,CY: 0/ 2
T-12 MAX WIND: 110 PRESSURE OF STEERING LEVEL (MB): 600 (MEAN=581)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 12.7 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 98.0 (MEAN=65.0)

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 0. 0. 0. 1. 1. 1. 0. 0. -1. -1. -2. -2.
SST POTENTIAL 1. 2. 3. 4. 4. 0. -5. -10. -17. -23. -29. -34.
VERTICAL SHEAR MAG 0. 0. 1. 1. 2. 3. 2. 1. -1. -2. -3. -5.
VERTICAL SHEAR ADJ 0. -1. -1. -2. -3. -4. -4. -4. -3. -4. -5. -7.
VERTICAL SHEAR DIR 0. 1. 2. 2. 3. 3. 3. 3. 2. 2. 1. 1.
PERSISTENCE -6. -10. -11. -11. -9. -7. -5. -4. -3. -3. -1. 0.
200/250 MB TEMP. 0. -1. -2. -3. -6. -8. -9. -11. -12. -13. -14. -13.
THETA_E EXCESS 0. 0. 0. 0. 0. -1. -1. -2. -3. -4. -6. -7.
700-500 MB RH 0. 1. 1. 1. 2. 2. 2. 2. 2. 2. 1. 1.
MODEL VTX TENDENCY 0. 1. 3. 4. 5. 6. -2. -11. -21. -30. -40. -41.
850 MB ENV VORTICITY 0. 0. 0. 1. 1. 2. 3. 3. 4. 5. 5. 5.
200 MB DIVERGENCE 1. 1. 2. 3. 3. 2. 2. 1. 0. 0. 0. 0.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
ZONAL STORM MOTION 0. -1. -1. -2. -3. -4. -4. -5. -4. -4. -4. -4.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 1. 1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1.
GOES PREDICTORS 0. 0. 0. 1. 1. 3. 4. 4. 5. 6. 6. 5.
OCEAN HEAT CONTENT 1. 2. 4. 4. 5. 4. 3. 2. 1. 1. 1. 0.
----------------------------------------------------------
TOTAL CHANGE -4. -4. 0. 3. 6. 3. -12. -30. -51. -70. -90.-101.

** 2013 E. Pacific RI INDEX EP022015 BLANCA 06/04/15 18 UTC **
( 30 KT OR MORE MAX WIND INCREASE IN NEXT 24 HR)

12 HR PERSISTENCE (KT): -25.0 Range:-22.0 to 38.5 Scaled/Wgted Val: 0.0/ 0.0
850-200 MB SHEAR (KT) : 5.8 Range: 18.7 to 1.4 Scaled/Wgted Val: 0.7/ 1.1
POT = MPI-VMAX (KT) : 79.4 Range: 40.3 to 141.7 Scaled/Wgted Val: 0.4/ 0.4
STD DEV OF IR BR TEMP : 12.7 Range: 38.9 to 2.4 Scaled/Wgted Val: 0.7/ 0.7
Heat content (KJ/cm2) : 72.2 Range: 3.6 to 75.9 Scaled/Wgted Val: 0.9/ 0.8
D200 (10**7s-1) : 102.4 Range:-11.0 to 135.3 Scaled/Wgted Val: 0.8/ 0.6
% area w/pixels <-30 C: 96.0 Range: 41.4 to 100.0 Scaled/Wgted Val: 0.9/ 0.5
850-700 MB REL HUM (%): 72.2 Range: 57.6 to 96.8 Scaled/Wgted Val: 0.4/ -0.1

Prob of RI for 25 kt RI threshold= 4% is 0.3 times the sample mean(13.1%)
Prob of RI for 30 kt RI threshold= 3% is 0.3 times the sample mean( 8.7%)
Prob of RI for 35 kt RI threshold= 2% is 0.3 times the sample mean( 6.0%)
Prob of RI for 40 kt RI threshold= 1% is 0.3 times the sample mean( 4.3%)

[Kingarabian]

Starting to think it went through two back to back ERC's?

Are ERC's convection fueled? e.g the more cold tops a storm has the higher likelihood of the storm going through an ERC?

[TheStormExpert]

Just yesterday morning I was thinking how good the NHC was doing in forecasting significant rapid intensification.

[Yellow Evan]

Starting to think it went through two back to back ERC's?

Are ERC's convection fueled? e.g the more cold tops a storm has the higher likelihood of the storm going through an ERC?

It might have done a Juliette 01-esque triple ERC. I don't know much about ERC's, but I do know that EPAC storms don't have as cold cloud tops as WPAC ones, and WPAC storms have more ERC's.

[MiamiensisWx]

I can't recall many Eastern Pacific systems that struggled so much with mid-level dry air south of 15° N, given their proximity to the Intertropical Convergence Zone (ITCZ). Apparently the building mid-level ridge behind Andres allowed some mid-level dry air to move NNE to SSW off the Mexican mountains, thereby becoming entrained into the circulation of Blanca. I never really expected the dry air to have such a significant impact, given Blanca's ample access to a moist low-level jet from the ITCZ. Still, I would give at least as much weight to the outer convective banding disrupting inflow into the inner core. Right now, Blanca looks more like a typical Atlantic storm of the past several seasons, and it is definitely no longer a hurricane in my view. Big kudos to the HWRF and GFDL for seeing something that even the NHC dismissed.

[cycloneye]

The experts chim in on the models and the ups and downs.


Ryan Maue ‏@RyanMaue · 6m6 minutes ago
HWRF and GFDL largely missed rapid intensification of Blanca but nailed the weakening, expansion of wind field, collapse of inner core.

Eric Blake ‏@EricBlake12 · 5m5 minutes ago
@RyanMaue they may have been right for partially the right reason-- shows how important the ocean is.

Ryan Maue ‏@RyanMaue · 2m2 minutes ago
@EricBlake12 GFS nailed RI as model has very vigorous convective scheme.

[MiamiensisWx]

How in the world is anyone going to be able to improve intensity forecasts considering all the variables at play?

Honestly, you need the ability and experience of a forecaster to fully succeed in the really difficult forecasting situations. Anyone who merely regurgitates the models--even the most reliable ones--without looking at real-time trends and the synoptic environment will tend to miss or dismiss seemingly minor factors that turn out to be much more significant than the reliable models suggested. In some situations, "unreliable" models can be more reliable than the ones that perform better in other set-ups. Even so, I don't believe for a second that we won't be able to improve intensity forecasts. The NHC made some excellent, though irregular and often halting, strides in forecasting intensities over the past few decades. We simply need better tools available: more funding for research into the global climate system, more/better monitoring systems, and forecasters willing to think outside the box, analyze each situation, and be true forecasters. Defeat is never an option in science, though a surprisingly large number of people (not you in particular, but generally) seem to think so.

[Yellow Evan]

I can't recall many Eastern Pacific systems that struggled so much with mid-level dry air south of 15° N, given their proximity to the Intertropical Convergence Zone (ITCZ). Apparently the building mid-level ridge behind Andres allowed some mid-level dry air to move NNE to SSW off the Mexican mountains, thereby becoming entrained into the circulation of Blanca. I never really expected the dry air to have such a significant impact, given Blanca's ample access to a moist low-level jet from the ITCZ. Still, I would give at least as much weight to the outer convective banding disrupting inflow into the inner core. Right now, Blanca looks more like a typical Atlantic storm of the past several seasons, and it is definitely no longer a hurricane in my view. Big kudos to the HWRF and GFDL for seeing something that even the NHC dismissed.

It wasn't dry air fully, it was SST's upwelling and an ERC.

This is probs a hurricane given the fact an eye of some sort is now present. As for the ATL, those storms don't even get that strong anymore

[Yellow Evan]

----- Current Analysis -----
Date : 04 JUN 2015 Time : 184500 UTC
Lat : 12:37:40 N Lon : 105:01:44 W


CI# /Pressure/ Vmax
5.1 / 965.7mb/ 92.4kt


Final T# Adj T# Raw T#
4.5 4.9 4.9

Estimated radius of max. wind based on IR :N/A km

Center Temp : +4.4C Cloud Region Temp : -51.3C

Scene Type : EYE

[Yellow Evan]

GFS pushed back it's peak for what it's worth.

[Kingarabian]

I can't recall many Eastern Pacific systems that struggled so much with mid-level dry air south of 15° N, given their proximity to the Intertropical Convergence Zone (ITCZ). Apparently the building mid-level ridge behind Andres allowed some mid-level dry air to move NNE to SSW off the Mexican mountains, thereby becoming entrained into the circulation of Blanca. I never really expected the dry air to have such a significant impact, given Blanca's ample access to a moist low-level jet from the ITCZ. Still, I would give at least as much weight to the outer convective banding disrupting inflow into the inner core. Right now, Blanca looks more like a typical Atlantic storm of the past several seasons, and it is definitely no longer a hurricane in my view. Big kudos to the HWRF and GFDL for seeing something that even the NHC dismissed.

Reminds me of Hurricane Isabel.

[Kingarabian]

GFS pushed back it's peak for what it's worth.

36 hours until the windows closes.

[TropicalAnalystwx13]

I can't recall many Eastern Pacific systems that struggled so much with mid-level dry air south of 15° N, given their proximity to the Intertropical Convergence Zone (ITCZ). Apparently the building mid-level ridge behind Andres allowed some mid-level dry air to move NNE to SSW off the Mexican mountains, thereby becoming entrained into the circulation of Blanca. I never really expected the dry air to have such a significant impact, given Blanca's ample access to a moist low-level jet from the ITCZ. Still, I would give at least as much weight to the outer convective banding disrupting inflow into the inner core. Right now, Blanca looks more like a typical Atlantic storm of the past several seasons, and it is definitely no longer a hurricane in my view. Big kudos to the HWRF and GFDL for seeing something that even the NHC dismissed.

It wasn't dry air fully, it was SST's upwelling and an ERC.

This is probs a hurricane given the fact an eye of some sort is now present. As for the ATL, those storms don't even get that strong anymore

Yeah, upwelling is by far the main cause for the weakening we observed yesterday. Once the core started faltering, dry air was more easily able to become entrained into the circulation and induce an eyewall replacement cycle. A series of unfortunate events for Blanca.

I have no doubt that the cyclone was well on its way to Category 5 status prior to the effects of upwelling. Its chances for such are slim now, however.

[Kingarabian]

Well this weakening surely is good news for the people of Baja.

[Yellow Evan]

GFS pushed back it's peak for what it's worth.

36 hours until the windows closes.

Around 36-48 hours, dry air should increase, and SST's and shear go down out hour 60.

[Yellow Evan]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 04 JUN 2015 Time : 191500 UTC
Lat : 12:46:42 N Lon : 105:04:49 W


CI# /Pressure/ Vmax
5.1 / 965.6mb/ 92.4kt


Final T# Adj T# Raw T#
4.5 4.4 2.3

Center Temp : +5.2C Cloud Region Temp : -48.4C

[cycloneye]

HURRICANE BLANCA DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
400 PM CDT THU JUN 04 2015

The hurricane has continued to weaken as it moves slowly over its
own cold wake. Dvorak T-numbers are decreasing, and the current
estimate of the initial intensity is 85 kt, which could be generous.
Most of the deep convection has spread out and is concentrated in
few bands well removed from the center. However, the hurricane
still has the chance to restrengthen as soon as it moves
away from the area where the upwelling has occurred. The NHC
forecast is again consistent with the SHIPS intensity guidance,
and allows some intensification during the next 24 to 36 hours.
Thereafter, increasing shear and cool waters should induce gradual
weakening as Blanca approaches the Baja California peninsula.

Blanca is moving toward the northwest or 320 degrees at 5 knots.
The subtropical ridge which has been blocking the motion of the
cyclone is already moving eastward, and most likely the hurricane
will continue northwestward or north-northwestward with some
increase of forward speed around the periphery of the ridge. The NHC
forecast is similar to the previous one and is very close to the
consensus of the ECMWF and the GFS global models. However, it
remains on the left side of the guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 12.8N 105.3W 85 KT 100 MPH
12H 05/0600Z 13.7N 106.1W 80 KT 90 MPH
24H 05/1800Z 15.3N 107.5W 85 KT 100 MPH
36H 06/0600Z 16.7N 108.7W 95 KT 110 MPH
48H 06/1800Z 18.2N 109.5W 85 KT 100 MPH
72H 07/1800Z 21.0N 110.5W 65 KT 75 MPH
96H 08/1800Z 24.0N 111.8W 35 KT 40 MPH
120H 09/1800Z 26.8N 113.5W 25 KT 30 MPH...INLAND

$$
Forecaster Avila

[Yellow Evan]

Eye needs to shrink if it wants to intensify again.

[Alyono]

Starting to think it went through two back to back ERC's?

Are ERC's convection fueled? e.g the more cold tops a storm has the higher likelihood of the storm going through an ERC?

nope. This is a typical upwelling response. The convection shifts to the periphery as the water temps are warmer there vs inside of the core