EPAC: BLANCA - Post-Tropical

[cycloneye]

Forget cat 5.


HURRICANE BLANCA DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
400 AM CDT THU JUN 04 2015

The small eye of Blanca has become less distinct in infrared
satellite images since yesterday afternoon. Subjective and
objective Dvorak T-numbers have subsequently decreased from their
peak, so the initial intensity has been lowered to 110 kt. It is
not clear whether the slight decrease in wind speed is a result of
an eyewall replacement cycle, drier air wrapping into the
circulation, or upwelling of cooler waters beneath the nearly
stationary hurricane. In any case, as the cyclone begins moving
northwestward, low vertical wind shear and warmer water, along the
forecast path of Blanca, favor strengthening during the next day or
so. The new NHC intensity forecast is close to the SHIPS guidance,
but shows a slightly lower peak intensity than the previous few
advisories. After 48 hours, increasing shear and cool waters should
induce weakening. A faster rate of weakening is expected after 72
hours, when the hurricane is forecast to move over SSTs below
26 deg C and into a drier and more stable air mass.

Blanca has remained nearly stationary during the past few hours.
The model guidance is in good agreement that the hurricane will
begin to move northwestward today while a mid-level ridge builds
over northern Mexico. Blanca should move northwestward to north-
northwestward at a faster forward speed during the next few days
between the aforementioned ridge and a mid-level trough extending
southwestward from southern California. The track guidance is
tightly clustered, but there are still significant differences in
the forward speed of the hurricane. As a result, the NHC track
remains close to the model consensus, between the faster GFS, and
the slower ECMWF model.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 11.9N 104.9W 110 KT 125 MPH
12H 04/1800Z 12.6N 105.6W 115 KT 130 MPH
24H 05/0600Z 13.9N 106.7W 120 KT 140 MPH
36H 05/1800Z 15.2N 107.9W 125 KT 145 MPH
48H 06/0600Z 16.7N 109.1W 120 KT 140 MPH
72H 07/0600Z 19.3N 110.5W 90 KT 105 MPH
96H 08/0600Z 22.5N 111.5W 50 KT 60 MPH
120H 09/0600Z 25.0N 113.0W 30 KT 35 MPH

$$
Forecaster Brown

[Alyono]

Regarding Nora, it had SST upwelling issues for a different reason. It was in its wake from Hurricane Linda 4 days prior.

no... it was primarily because it remained stationary for so long.

Reintensification will occur. However, this will weaken signiifcantly

[Yellow Evan]

Forget cat 5.

I wouldn't quite yet, regardless on what the NHC forecasts.

[SouthDadeFish]

The structure of Hurricane Blanca has changed significantly since yesterday. The eye is much larger now.

[cycloneye]

Eric Blake ‏@EricBlake12 · 4m4 minutes ago
Will be very interested to see the SSTs left behind after #Blanca moves on- notably disrupted inner core.

[Yellow Evan]

I think it underwent an ERC.

[Yellow Evan]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* BLANCA EP022015 06/04/15 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 100 97 97 101 102 107 103 97 79 60 39 21 DIS
V (KT) LAND 100 97 97 101 102 107 103 97 79 60 39 21 DIS
V (KT) LGE mod 100 95 92 92 93 95 91 81 68 55 43 32 24
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 5 5 6 8 9 10 10 13 17 22 18 13 13
SHEAR ADJ (KT) 7 10 8 6 7 3 5 9 3 0 3 4 6
SHEAR DIR 47 81 82 83 113 121 141 111 111 136 178 211 168
SST (C) 30.3 30.2 30.1 30.0 29.8 29.0 27.7 26.6 25.5 24.1 22.2 21.4 20.9
POT. INT. (KT) 166 166 165 164 163 154 140 128 117 103 83 73 68
200 MB T (C) -51.8 -51.3 -51.0 -51.2 -51.1 -50.8 -51.1 -50.5 -50.9 -50.7 -51.5 -51.4 -51.2
TH_E DEV (C) 8 8 8 8 8 8 7 7 5 5 3 3 1
700-500 MB RH 79 74 75 72 73 71 66 60 56 51 49 45 40
MODEL VTX (KT) 33 36 35 36 35 38 37 39 33 27 21 15 9
850 MB ENV VOR 62 69 74 80 86 89 66 61 53 63 54 34 21
200 MB DIV 116 94 88 62 56 62 33 37 -28 -15 -32 7 2
700-850 TADV -3 -3 -1 -3 -2 0 1 1 0 -4 0 -1 -2
LAND (KM) 682 641 608 581 563 498 496 455 313 171 78 10 100
LAT (DEG N) 12.2 12.8 13.4 14.0 14.6 16.1 17.6 18.8 20.1 21.6 23.6 24.8 25.4
LONG(DEG W) 104.9 105.4 105.9 106.5 107.0 108.2 109.4 110.0 110.4 110.9 111.6 112.4 113.1
STM SPEED (KT) 4 8 8 8 9 9 8 7 7 9 9 6 5
HEAT CONTENT 94 91 89 75 45 31 8 3 0 0 0 0 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):250/ 1 CX,CY: 0/ 0
T-12 MAX WIND: 120 PRESSURE OF STEERING LEVEL (MB): 572 (MEAN=581)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 11.9 (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 0. 1. 2. 2. 0. -6. -13. -20. -28. -35. -42. -48.
VERTICAL SHEAR MAG 0. 0. 0. 0. 0. 1. 2. 2. 0. -1. -2. -3.
VERTICAL SHEAR ADJ -1. -1. -2. -2. -3. -3. -3. -3. -3. -3. -4. -5.
VERTICAL SHEAR DIR 1. 2. 3. 3. 5. 5. 5. 5. 4. 4. 4. 3.
PERSISTENCE -6. -8. -9. -9. -6. -4. -3. -1. -1. -1. 0. 1.
200/250 MB TEMP. 0. -1. -2. -3. -5. -7. -9. -10. -11. -12. -13. -13.
THETA_E EXCESS 0. 0. 0. 0. 0. -1. -1. -2. -3. -4. -5. -6.
700-500 MB RH 0. 1. 1. 1. 2. 2. 3. 3. 3. 2. 2. 2.
MODEL VTX TENDENCY 1. 1. 3. 3. 7. 7. 10. 0. -7. -16. -24. -32.
850 MB ENV VORTICITY 0. 0. 0. 1. 1. 2. 3. 3. 4. 4. 5. 5.
200 MB DIVERGENCE 1. 1. 2. 2. 2. 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. -5. -5. -4. -4. -4. -4.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1.
GOES PREDICTORS 0. 0. 0. 0. 1. 3. 4. 4. 5. 6. 6. 6.
OCEAN HEAT CONTENT 1. 2. 4. 5. 5. 5. 3. 2. 2. 1. 1. 0.
----------------------------------------------------------
TOTAL CHANGE -3. -3. 1. 2. 7. 3. -3. -21. -40. -61. -79. -98.

** 2013 E. Pacific RI INDEX EP022015 BLANCA 06/04/15 12 UTC **
( 30 KT OR MORE MAX WIND INCREASE IN NEXT 24 HR)

12 HR PERSISTENCE (KT): -20.0 Range:-22.0 to 38.5 Scaled/Wgted Val: 0.0/ 0.1
850-200 MB SHEAR (KT) : 6.7 Range: 18.7 to 1.4 Scaled/Wgted Val: 0.7/ 1.0
POT = MPI-VMAX (KT) : 64.8 Range: 40.3 to 141.7 Scaled/Wgted Val: 0.2/ 0.3
STD DEV OF IR BR TEMP : 11.9 Range: 38.9 to 2.4 Scaled/Wgted Val: 0.7/ 0.8
Heat content (KJ/cm2) : 78.8 Range: 3.6 to 75.9 Scaled/Wgted Val: 1.0/ 0.9
D200 (10**7s-1) : 83.2 Range:-11.0 to 135.3 Scaled/Wgted Val: 0.6/ 0.5
% area w/pixels <-30 C: 93.0 Range: 41.4 to 100.0 Scaled/Wgted Val: 0.9/ 0.4
850-700 MB REL HUM (%): 71.6 Range: 57.6 to 96.8 Scaled/Wgted Val: 0.4/ -0.1

Prob of RI for 25 kt RI threshold= 26% is 2.0 times the sample mean(13.1%)
Prob of RI for 30 kt RI threshold= 24% is 2.7 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%)

## ANNULAR HURRICANE INDEX (AHI) EP022015 BLANCA 06/04/15 12 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=5 NFAIL=2 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

[Yellow Evan]

Levi Cowan ‏@TropicalTidbits 57s57 seconds ago

#Blanca hit hard by cooled water, but is about to have one of the best possible outflow patterns to aid recovery.

[cycloneye]

Below cat 3.


HURRICANE BLANCA DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
1000 AM CDT THU JUN 04 2015

It appears that the combination of upwelling and an eyewall
replacement cycle has resulted in significant weakening of
Blanca during the past 18 hours or so. The eye is not as clear as
it was yesterday, and the deep convection is no longer symmetric
around what is left of the eye. Based on decreasing subjective and
objective T-numbers, the initial intensity has been adjusted down to
95 kt at this time. However, as soon as Blanca moves out of the area
where the upwelling has occurred in 12 to 24 hours, another round of
strengthening is anticipated, but not as much as indicated
yesterday. The NHC forecast is consistent with the SHIPS intensity
guidance, which still insists on forecasting restrengthening as the
cyclone moves again over warm waters. Beyond 48 hours, increasing
shear and cool waters should induce gradual weakening as Blanca
approaches the Baja California peninsula.

Satellite fixes indicate that Blanca has begun to move slowly toward
the northwest or 325 degrees at 3 knots. The subtropical ridge which
has been blocking the motion of the cyclone is forecast to shift
eastward by most of the global models while a trough approaches the
west coast of the United States. This steering pattern favors a
general northwest to north-northwest track during the next 5 days.
The NHC forecast is similar to the previous one and follows closely
the consensus of the ECMWF and the GFS global models.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 12.3N 105.1W 95 KT 110 MPH
12H 05/0000Z 13.2N 105.7W 95 KT 110 MPH
24H 05/1200Z 14.5N 107.0W 105 KT 120 MPH
36H 06/0000Z 16.0N 108.5W 105 KT 120 MPH
48H 06/1200Z 17.5N 109.5W 105 KT 120 MPH
72H 07/1200Z 20.0N 110.5W 90 KT 105 MPH
96H 08/1200Z 23.2N 111.5W 50 KT 60 MPH
120H 09/1200Z 26.0N 113.3W 25 KT 30 MPH

$$
Forecaster Avila

[tolakram]

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

[galaxy401]

Don't worry, we can still get a Category 5 sometime this year. (Hint: It will be my name )

[Kingarabian]

I still think it has too much time left for it to not flirt with cat.5 status.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Yellow Evan]

Seems to be finishing an ERC.

[TropicalAnalystwx13]

Blanca is finally moving, meaning that it should begin to slowly intensify this afternoon. The cyclone needs to fire core convection and shrink its eye if it wants to take on a more rapid pace of strengthening.

[Yellow Evan]

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

----- Current Analysis -----
Date : 04 JUN 2015 Time : 171500 UTC
Lat : 12:31:01 N Lon : 104:58:56 W


CI# /Pressure/ Vmax
5.1 / 968.4mb/ 92.4kt


Final T# Adj T# Raw T#
4.7 4.9 4.9

Estimated radius of max. wind based on IR : 31 km

Center Temp : +4.8C Cloud Region Temp : -49.9C

Scene Type : EYE

[cycloneye]

Moving but still going down.

EP, 02, 2015060418, , BEST, 0, 125N, 1050W, 85, 975, HU

[CrazyC83]

Is upwelling possible to forecast in real time? I think the time of year (June instead of August) didn't help either.

[Yellow Evan]

Is upwelling possible to forecast in real time? I think the time of year (June instead of August) didn't help either.

No.

SST's are at record levels typically seen in August, FYI.

[Yellow Evan]

Idk ADT had a large eye scene

----- Current Analysis -----
Date : 04 JUN 2015 Time : 174500 UTC
Lat : 12:33:43 N Lon : 105:00:46 W


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


Final T# Adj T# Raw T#
4.6 4.5 4.5

Estimated radius of max. wind based on IR : 46 km

Center Temp : +6.6C Cloud Region Temp : -51.4C

Scene Type : LARGE EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : EAST PACIFIC

[Kingarabian]

Damn that eye is huge.

Does the GFS still have 913mb tomorrow?