EPAC: SANDRA - Post-Tropical

[Ntxw]

Cloud tops are there to support Cat.4 once the eye clears again.

If only recon was in this, cloud tops are very cold again. These rapidly intensifying compact systems are always something else.

[Kingarabian]

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

             ----- Current Analysis -----
     Date :  26 NOV 2015    Time :   003000 UTC
      Lat :   13:18:53 N     Lon :  110:07:26 W

     
                CI# /Pressure/ Vmax
                5.8 / 953.0mb/109.8kt

     
             Final T#  Adj T#  Raw T#
                5.8     6.3     6.3

 Estimated radius of max. wind based on IR :<10 km

 Center Temp : -21.2C    Cloud Region Temp : -71.2C

 Scene Type : PINHOLE EYE

[cycloneye]

Ryan Maue ‏@RyanMaue · 22m22 minutes ago
Satellite intensity estimate of Hurricane Sandra up to T-6.0 ... likely upgrade to Cat 4 115-knots next advisory.

[Kingarabian]

Eye is WMG?

[cycloneye]

HURRICANE SANDRA DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP222015
800 PM MST WED NOV 25 2015

The intensification of Sandra seems to have slowed during the past
few hours. The cloud tops in the eyewall have continued to cool
with temperatures now colder than -80C. However, as this has
occurred the eye has become less distinct. Satellite intensity
estimates are 115 kt from SAB and 102 kt from TAFB, and there is a
recent CIMSS ADT estimate of 110 kt. A blend of these data is used
for the initial intensity of 105 kt.

The initial motion is now 320/7. Sandra is moving around the
western end of a mid- to upper-level ridge over southern Mexico, and
during the next 96 hours it should move into southwesterly flow
between the ridge and a deep-layer trough over the western United
States. While the guidance is generally in good agreement with
this scenario, there remains some spread between the slower and
farther west ECMWF and the faster and farther east GFS. As seen in
the previous advisory, this is due to the GFS keeping Sandra a
stronger system than does the ECMWF. The new track forecast is
more or less an update of the previous forecast, but remains slower
than the model consensus in deference to the ECMWF, whose weaker
forecast again looks more realistic at this time. The new forecast
has the center of Sandra passing near the southern end of the Baja
California peninsula between 48-72 hours and subsequently moving
into mainland Mexico between 72-96 hours.

Some additional strengthening is possible tonight. After that,
Sandra is expected to encounter rapidly increasing southwesterly
vertical wind shear, which should cause rapid weakening as the
center approaches Baja California and mainland Mexico. The new
intensity forecast is near the intensity consensus IVCN through 48
hours, and then it is a little stronger than the guidance at 72
hours. After Sandra makes landfall in Mexico, it is forecast to
dissipate quickly over the mountains.

Although Sandra is forecast to weaken, it is still too soon to know
exactly how it will affect portions of the southern Baja California
peninsula or the west coast of mainland Mexico. Watches will not
be required on this advisory. However, interests in those areas
should continue to monitor the progress of Sandra.


FORECAST POSITIONS AND MAX WINDS

INIT 26/0300Z 13.6N 110.4W 105 KT 120 MPH
12H 26/1200Z 14.9N 110.9W 110 KT 125 MPH
24H 27/0000Z 16.7N 111.2W 100 KT 115 MPH
36H 27/1200Z 18.5N 110.9W 85 KT 100 MPH
48H 28/0000Z 20.4N 110.3W 70 KT 80 MPH
72H 29/0000Z 24.0N 108.5W 35 KT 40 MPH
96H 30/0000Z 28.0N 107.0W 20 KT 25 MPH...POST-TROP/INLAND
120H 01/0000Z...DISSIPATED

$$
Forecaster Beven

[Ntxw]

Never mind cat 4, could she make a run at brief cat 5 by morning? Especially if she can really warm that small eye. Man I wish there was recon now...





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

----- Current Analysis -----
Date : 26 NOV 2015 Time : 023000 UTC
Lat : 13:35:33 N Lon : 110:12:47 W


CI# /Pressure/ Vmax
6.0 / 948.5mb/115.0kt


Final T# Adj T# Raw T#
6.0 6.2 6.2

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

Center Temp : -55.9C Cloud Region Temp : -73.6C

Scene Type : EYE

[Yellow Evan]

Eye is WMG?

Not even close. WMG is 10C. This had been between -30 and -65C. In the CDO department, however, we are fine.

[Kingarabian]

No idea why the NHC went with 105kts.

[Kingarabian]

Eye is WMG?

Not even close. WMG is 10C. This had been between -30 and -65C. In the CDO department, however, we are fine.

Oops I completely disregarded eye temps.

Would it classify as CMG?

[Ntxw]

No idea why the NHC went with 105kts.

This is way more than 105kts...

[Yellow Evan]

Eye is WMG?

Not even close. WMG is 10C. This had been between -30 and -65C. In the CDO department, however, we are fine.

Oops I completely disregarded eye temps.

Would it classify as CMG?

CDO is surrounded by CMG, but not embedded .5 of a degree in it. It is embedded in W, which leads to an eye number of 6.0 and a LG eye in CMG leading to no eye adjusting, resulting in what IMO would be a DT of T6.0.

[Ntxw]

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

----- Current Analysis -----
Date : 26 NOV 2015 Time : 030000 UTC
Lat : 13:39:00 N Lon : 110:08:34 W


CI# /Pressure/ Vmax
6.2 / 944.4mb/119.8kt


Final T# Adj T# Raw T#
6.2 6.7 6.7

Estimated radius of max. wind based on IR :<10 km

Center Temp : -27.4C Cloud Region Temp : -74.8C

Scene Type : PINHOLE EYE

[Kingarabian]

No idea why the NHC went with 105kts.

This is way more than 105kts...

I think the NHC got fooled by its presumed cool eye.

I personally thought they would be conservative and go with 110kts.

[Kingarabian]

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

             ----- Current Analysis -----
     Date :  26 NOV 2015    Time :   033000 UTC
      Lat :   13:42:35 N     Lon :  110:10:29 W

     
                CI# /Pressure/ Vmax
                6.3 / 942.2mb/122.2kt

     
             Final T#  Adj T#  Raw T#
                6.3     6.9     6.9

 Estimated radius of max. wind based on IR :<10 km

 Center Temp : -26.9C    Cloud Region Temp : -75.5C

 Scene Type : PINHOLE EYE 

[Ntxw]

I personally thought they would be conservative and go with 110kts.

Yeah the eye is holding it back a little but still. As soon as she blinks, with cold cloud tops T7.0s

If not for what happened a month earlier, we would be staring at this right now and making arguments for cat 5 push. This is better looking on satellite and deeper convection imo than the second strongest system this season Jimena.

[Ntxw]

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

----- Current Analysis -----
Date : 26 NOV 2015 Time : 040000 UTC
Lat : 13:46:18 N Lon : 110:06:12 W


CI# /Pressure/ Vmax
6.4 / 940.1mb/124.6kt


Final T# Adj T# Raw T#
6.4 7.0 7.0

Estimated radius of max. wind based on IR :<10 km

Center Temp : -26.3C Cloud Region Temp : -76.3C

Scene Type : PINHOLE EYE

[NotoSans]

Sandra is being underestimated by Dvorak right now. Eye temp is in DG range in GOES-13 imagery and LG range in GOES-15. However, Sandra is possibly not well captured by both satellites due to large viewing angle, which ultimately lead to a lower intensity estimate.

[Yellow Evan]

105 knts is such a bad call, but I know Beven likes to go at or below the 3 way avg with slow moving EPAC storms.

[Kingarabian]

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

             ----- Current Analysis -----
     Date :  26 NOV 2015    Time :   053000 UTC
      Lat :   13:58:11 N     Lon :  110:17:54 W

     
                CI# /Pressure/ Vmax
                6.8 / 930.8mb/134.8kt

     
             Final T#  Adj T#  Raw T#
                6.8     6.8     6.8

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

 Center Temp : -52.1C    Cloud Region Temp : -76.5C

 Scene Type : EYE 


[Kingarabian]

105 knts is such a bad call, but I know Beven likes to go at or below the 3 way avg with slow moving EPAC storms.

Agreed.

Sure the eye was cooling. But those 80C tops were wrapping around clearly signaled intensification. We saw what pin-hole eyed systems are capable of (Patricia).