EPAC: BLANCA - Post-Tropical

[cycloneye]

Peaks at 135kts.


HURRICANE BLANCA DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
1000 PM CDT WED JUN 03 2015

Blanca's convection has continued to decrease in intensity this
evening, and the eye observed in infrared satellite imagery has been
filling. Dvorak T-numbers have dropped across the board, but the
intensity is being held at 120 kt based on a blend of current
intensity numbers. Microwave imagery does not show the development
of concentric eyewalls, which often leads to disruptions in
intensification, but an 0030Z SSMIS pass did indicate that some dry
air may be wrapping into the circulation. There's also the
possibility that upwelling of cooler water could be an issue, but
it's impossible to know that in real time.

The hurricane has been drifting southwestward during the past 6-12
hours. Model guidance is in agreement that Blanca should begin
to accelerate toward the northwest on Thursday in response to a
amplifying mid-level trough along the U.S. west coast and building
high pressure over northern Mexico. However, some of the track
models (most notably the GFS, HWRF, and GFDL) have again shifted
westward a bit. As a result, the updated NHC track forecast is
slightly west of the previous forecast between 72-120 hours.

Despite the hurricane's recent convective changes, the microwave
data showed that the eyewall remains intact, and low vertical shear
and a generally moist environment should be conducive to support
further strengthening during the next 36 hours. In addition, once
Blanca begins moving toward the northwest, it would escape any
potential areas of upwelled cooler water. The GFS, ECMWF, SHIPS,
and LGEM all show Blanca peaking in intensity at 36 hours, and the
updated NHC intensity forecast follows suit by showing a maximum
intensity right near the category 4/5 boundary Friday morning.
After that, increasing shear, cooler water, and a drier, more stable
atmosphere should lead to rapid weakening, especially after 72
hours.

FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 12.0N 104.7W 120 KT 140 MPH
12H 04/1200Z 12.6N 105.1W 125 KT 145 MPH
24H 05/0000Z 13.7N 106.0W 130 KT 150 MPH
36H 05/1200Z 15.0N 107.2W 135 KT 155 MPH
48H 06/0000Z 16.4N 108.5W 130 KT 150 MPH
72H 07/0000Z 19.1N 110.2W 100 KT 115 MPH
96H 08/0000Z 21.9N 111.3W 60 KT 70 MPH
120H 09/0000Z 24.9N 112.7W 35 KT 40 MPH

$$
Forecaster Berg

[Alyono]

remainds me of Nora in 1997

this has probably peaked. There should be a reorganization now with a much broader rmw due to the upwelling

[Yellow Evan]

remainds me of Nora in 1997

this has probably peaked. There should be a reorganization now with a much broader rmw due to the upwelling

Why won't it be able to intensify again once it starts moving? That's what models unanimously agree.

[TropicalAnalystwx13]

Peaks at 135kts.


HURRICANE BLANCA DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
1000 PM CDT WED JUN 03 2015

Blanca's convection has continued to decrease in intensity this
evening, and the eye observed in infrared satellite imagery has been
filling. Dvorak T-numbers have dropped across the board, but the
intensity is being held at 120 kt based on a blend of current
intensity numbers. Microwave imagery does not show the development
of concentric eyewalls, which often leads to disruptions in
intensification, but an 0030Z SSMIS pass did indicate that some dry
air may be wrapping into the circulation. There's also the
possibility that upwelling of cooler water could be an issue, but
it's impossible to know that in real time.

The hurricane has been drifting southwestward during the past 6-12
hours. Model guidance is in agreement that Blanca should begin
to accelerate toward the northwest on Thursday in response to a
amplifying mid-level trough along the U.S. west coast and building
high pressure over northern Mexico. However, some of the track
models (most notably the GFS, HWRF, and GFDL) have again shifted
westward a bit. As a result, the updated NHC track forecast is
slightly west of the previous forecast between 72-120 hours.

Despite the hurricane's recent convective changes, the microwave
data showed that the eyewall remains intact, and low vertical shear
and a generally moist environment should be conducive to support
further strengthening during the next 36 hours. In addition, once
Blanca begins moving toward the northwest, it would escape any
potential areas of upwelled cooler water. The GFS, ECMWF, SHIPS,
and LGEM all show Blanca peaking in intensity at 36 hours, and the
updated NHC intensity forecast follows suit by showing a maximum
intensity right near the category 4/5 boundary Friday morning.
After that, increasing shear, cooler water, and a drier, more stable
atmosphere should lead to rapid weakening, especially after 72
hours.

FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 12.0N 104.7W 120 KT 140 MPH
12H 04/1200Z 12.6N 105.1W 125 KT 145 MPH
24H 05/0000Z 13.7N 106.0W 130 KT 150 MPH
36H 05/1200Z 15.0N 107.2W 135 KT 155 MPH
48H 06/0000Z 16.4N 108.5W 130 KT 150 MPH
72H 07/0000Z 19.1N 110.2W 100 KT 115 MPH
96H 08/0000Z 21.9N 111.3W 60 KT 70 MPH
120H 09/0000Z 24.9N 112.7W 35 KT 40 MPH

$$
Forecaster Berg

Seems like a reasonable forecast. This little bump in the road wasn't expected, but I still think this has the potential to become a Category 5. Doing so on Friday would still make it the earliest of such intensity on record.

Every storm has surprises.

[Kingarabian]

remainds me of Nora in 1997

this has probably peaked. There should be a reorganization now with a much broader rmw due to the upwelling

You don't see it getting stronger than 120kts?

[Yellow Evan]

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

[cycloneye]

Ryan Maue ‏@RyanMaue · 11m11 minutes ago
Hurricane Blanca has really hit the skids. Not much doubt that upwelled cool water is causing weakening.

[Kingarabian]

Smaller core.

[Yellow Evan]

Looks more N to S aligned.

Have a feeling this will be back on track tomorrow.

[Yellow Evan]

Ryan Maue ‏@RyanMaue 3m3 minutes ago

@TropicalTidbits global RTOFS is coupled -- it has been upwelling beneath Blanca

[TropicalAnalystwx13]

Ryan Maue ‏@RyanMaue 3m3 minutes ago

@TropicalTidbits global RTOFS is coupled -- it has been upwelling beneath Blanca

There's no way SSTs has been upwelled below 15C. Even in the most extreme case I can remember, Leslie 2012, it only upwelled to 23C after sitting and spinning with a large expanse of convection for days. And even then, the warm water was much shallower for Leslie than it is for Blanca.

[Yellow Evan]

Still no ERC.

[Yellow Evan]

----- Current Analysis -----
Date : 04 JUN 2015 Time : 024500 UTC
Lat : 11:56:58 N Lon : 104:50:59 W


CI# /Pressure/ Vmax
6.4 / 941.0mb/124.6kt


Final T# Adj T# Raw T#
5.5 5.7 5.0

Center Temp : -48.6C Cloud Region Temp : -60.4C

[galaxy401]

If it wants to reach category 5 then it needs to get moving now.

[Yellow Evan]

If it wants to reach category 5 then it needs to get moving now.

GFS expects it to start moving at around 12z. Should give it 24-36 more hours to intensify.

[Yellow Evan]

Despite no microwave ERC, satellite looks for sure there's an ERC.

[TropicalAnalystwx13]

The eye is making somewhat of a return after disappearing for a few frames.

[Kingarabian]

[Kingarabian]

The eye is making somewhat of a return after disappearing for a few frames.

D-max?

[Kingarabian]