CPAC: DARBY - Post-Tropical

[1900hurricane]

I still think dry air is getting to it to some degree. The cloud tops look like they belong to an Atlantic Hurricane leaving the subtropics, not an EPac hurricane at 16*N.

[Kingarabian]

Yeah. Low resolution from AMSU but you can see the dry air present within the circulation:



That said, looks like it's taking on annular characteristics.

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
200 PM PDT THU JUL 14 2016

Darby is a little better organized this afternoon. Visible
satellite imagery shows a well-defined convective band wrapping
almost 1.5 times around the center, which has resulted in the
development of a banding-type eye. Subjective and objective Dvorak
estimates from the various agencies have remained steady or
increased slightly since this morning; therefore the initial
intensity is raised to 75 kt. Darby may still have to contend with
some northeasterly shear for another 12-24 hours, but the shear then
decreases after that time. On the other hand, oceanic heat content
values ahead of the hurricane fall off precipitously in about 12
hours. Considering these competing factors, some gradual
strengthening is expected during the next day or so, followed by
slow weakening until the end of the forecast period due to cooler
SSTs. The updated NHC intensity forecast is near the SHIPS and
Florida State Superensemble, which are at the top end of the
intensity guidance.

Darby continues moving westward, or 280/12 kt. Strong mid-level
ridging to the north of the hurricane is expected to persist for
much of the forecast period, keeping Darby on a westward or perhaps
west-northwestward path through day 5. The track guidance remains
tightly clustered, as it has been for the past couple of days,
although the overall guidance envelope shifted northward on this
cycle, especially through day 3. Therefore, the official NHC track
forecast has been adjusted northward, but it is near the southern
edge of the guidance suite close to the GFS, GFS ensemble mean, and
UKMET.

FORECAST POSITIONS AND MAX WINDS

INIT 14/2100Z 15.9N 118.1W 75 KT 85 MPH
12H 15/0600Z 16.3N 119.8W 80 KT 90 MPH
24H 15/1800Z 16.8N 121.8W 85 KT 100 MPH
36H 16/0600Z 17.2N 123.9W 85 KT 100 MPH
48H 16/1800Z 17.5N 125.7W 80 KT 90 MPH
72H 17/1800Z 17.8N 129.5W 70 KT 80 MPH
96H 18/1800Z 18.2N 134.0W 60 KT 70 MPH
120H 19/1800Z 18.5N 138.5W 50 KT 60 MPH

$$
Forecaster Berg

[Yellow Evan]

Likely upwelling cold wake from Blas/Celia to some extent given how warm but thick the CDO is.

[TropicalAnalystwx13]

Yeah, I'd go with the upwelling option. Darby's current structure isn't really favorable for dry air intrusions. The shallowness of the convection makes me think it's passing over a patch of water in the 25.5-26.5C range.

If convection rebounds tonight, this could make a run at upper-end Cat 3 or even Cat 4 intensity based on the organized inner core and defined eye apparent on satellite already.

[Kingarabian]

Looks like cooler waters limiting deep convection thus allowing dry air to enter. Looks like Celia when it was a cat.2.

[TropicalAnalystwx13]

Some re-invigoration in the more recent frames. Hopefully the start of a trend.



Still a beautiful presentation on visible:

[Yellow Evan]

 https://twitter.com/EricBlake12/status/753714557739081729

[stormwise]

warming tops and very noticeable @700mb, agrees with 1900Hurricane had been battling dry air last few days.

[Kingarabian]

12Z EPS big shift north compared to the OP GFS and OP Euro. I don't like this current setup for Hawaii. With the way the models have been under doing the weakness, this could be a problem.

[Yellow Evan]

Code: Select all

             ----- Current Analysis -----
     Date :  14 JUL 2016    Time :   223000 UTC
      Lat :   15:48:34 N     Lon :  118:14:21 W

     
                CI# /Pressure/ Vmax
                4.8 / 975.6mb/ 84.8kt

     
             Final T#  Adj T#  Raw T#
                4.8     4.8     4.8

 Estimated radius of max. wind based on IR : 26 km

 Center Temp : -15.1C    Cloud Region Temp : -51.9C

 Scene Type : EYE

[Kingarabian]

Nearly closed eyewall. Definitely has strengthened.

[stormwise]

Code: Select all

             ----- Current Analysis -----
     Date :  14 JUL 2016    Time :   223000 UTC
      Lat :   15:48:34 N     Lon :  118:14:21 W

     
                CI# /Pressure/ Vmax
                4.8 / 975.6mb/ 84.8kt

     
             Final T#  Adj T#  Raw T#
                4.8     4.8     4.8

 Estimated radius of max. wind based on IR : 26 km

 Center Temp : -15.1C    Cloud Region Temp : -51.9C

 Scene Type : EYE

----- Current Analysis -----
Date : 14 JUL 2016 Time : 233000 UTC
Lat : 15:45:06 N Lon : 118:38:31 W


CI# /Pressure/ Vmax
4.8 / 975.6mb/ 84.8kt


Final T# Adj T# Raw T#
4.7 4.4 4.4

Estimated radius of max. wind based on IR : 40 km

Center Temp : -0.1C Cloud Region Temp : -51.6C

Scene Type : LARGE EYE

[Yellow Evan]

Shouldn't DT be 4.0?

TXPZ24 KNES 150025
TCSENP

A. 05E (DARBY)

B. 15/0000Z

C. 15.8N

D. 118.6W

E. ONE/GOES-W

F. T4.5/4.5/D0.5/24HRS

G. IR/EIR/VIS

H. REMARKS...AN OW EYE SURROUNDED BY MG IS EMBEDDED IN DG. THIS RESULTS
IN A DT OF 4.5. MET AND PT AGREE AT 5.O. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...MICHAEL

[Yellow Evan]

Not closed any longer.

[Kingarabian]

[img]http://i.imgur.com/nJjxKdv.jpg[/mg]

Not closed any longer.

That pass is 30 minutes older than the one I posted earlier (which shows a closed eyewall).

[stormwise]

Darby is looking cinnamon rollish atm, A precursor before going fully annular.

[Alyono]

This is getting VERY far north so far to the east. This would be unprecedented for this to have a significant impact on Hawaii.

Typically, you need systems no farther north than 12N this far east

[Yellow Evan]

Code: Select all

EP, 05, 2016071500,   , BEST,   0, 159N, 1186W,  80,  982, HU

[Kingarabian]

This is getting VERY far north so far to the east. This would be unprecedented for this to have a significant impact on Hawaii.

Typically, you need systems no farther north than 12N this far east

Could be why EPS shifting north.

Because the GFS and the Euro are showing a dip in latitude similar to Flossing 2007.