CPAC: DARBY - Post-Tropical

[Alyono]

Convections seems to be expanding. Sign that warm waters are near?

its over waters >26C already

think its the dry air and moderate shear. Convection just cannot sustain itself. It is firing fine

[Alyono]

even a hurricane watch would not be inappropriate in this case as hurricane force winds are possible for the eastern half of the Big Island

[Kingarabian]

00z GFS a bit more East.

[stormwise]

Yeah it does in 45hrs as @ a weak 1012mb.

[Alyono]

it
s a lot lower than 1012. Only use surface pressure

[Kingarabian]

Trouble maintaining convection. But with that Convection expanding to the N and NW, this will be a big rain event.

[cycloneye]

TROPICAL STORM DARBY DISCUSSION NUMBER 43
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP052016
1100 PM HST THU JUL 21 2016

Cloud tops associated with Darby have warmed significantly over the
past six hours, while overall organization has decreased. Outflow
remains best to the north and northeast, but has become hindered to
the southeast. Objective Dvorak satellite intensity estimates
remain 3.0/45 knots from all three analysis centers (HFO, JTWC,
SAB), but an 0324 UTC WINDSAT pass showed a swath of 55 kt winds
across the northeast semicircle close to the LLCC, prompting a
continued initial intensity of 55 kt for this advisory. Initial
reconnaissance into Darby by the 53rd Weather Reconnaissance
Squadron is scheduled for Friday morning, and their data will give
us a much better idea as to Darby's intensity and size.

Initial motion is 265/09 kt, representing a bit of slowing since
the last advisory. WINDSAT and SSMIS from earlier this evening
hinted that Darby was tilted slightly to the northeast with height,
consistent with SHIPS showing southwesterly shear between 10 and 15
knots. The initial motion slightly south of due west may be due to
earlier advisory positions placed slightly too far north. At any
rate, Darby continues to move along the southern flank of a ridge
centered north of Hawaii and will continue to do so through 36
hours. Afterwards, a deep low will dig south and weaken the ridge,
slowing this system down and allowing Darby to curve gently
northwestward from 36 to 72 hours, then northward beyond 72 hours.
Track guidance shifted slightly to the right, placing the current
forecast firmly within a tightening envelope. The forecast track
was altered slightly to the left through 12 hours for initial
motion, then to the right beyond 72 hours to stay close to TVCN
consensus. The rest of the track, including that portion closest to
the Hawaiian Islands, is unchanged.

The intensity forecast is close to the previous one, with shear
initially weakening through 36 hours, then strengthening rapidly to
30 knots from the southwest at 72 hours. The effects of shear and
slightly warmer SSTS are expected to essentially cancel each other
out through 48 hours, with the weakening effects of shear becoming
dominant afterwards as Darby gains latitude. Any weakening effects
that land interaction would have on Darby intensity have been
ignored so far.

Interests outside of the watch and warning areas in the Hawaiian
islands should monitor the progress of Darby, as it could eventually
have impacts on all islands through early next week. Remember, it is
important not to focus too closely on the exact track and intensity
forecasts because the average track error 72 hours out is near 100
miles, while the average intensity error is about 15 kt. In
addition, the hazards of a tropical cyclone can extend over a broad
area well away from the center.

FORECAST POSITIONS AND MAX WINDS

INIT 22/0900Z 18.8N 148.1W 55 KT 65 MPH
12H 22/1800Z 18.7N 149.5W 55 KT 65 MPH
24H 23/0600Z 18.9N 151.5W 55 KT 65 MPH
36H 23/1800Z 19.4N 153.3W 55 KT 65 MPH
48H 24/0600Z 20.1N 154.7W 55 KT 65 MPH
72H 25/0600Z 22.1N 157.4W 45 KT 50 MPH
96H 26/0600Z 24.4N 159.5W 40 KT 45 MPH
120H 27/0600Z 28.1N 160.9W 35 KT 40 MPH

$$
Forecaster Powell

[Kingarabian]

Placeholder. But they'll take off in 6 hours.

[NDG]

I really doubt the recon will find 55 knot winds later today if it keeps looking like this. The dryer air finally got to it due the increasing shear.

[stormwise]

----- Current Analysis -----
Date : 22 JUL 2016 Time : 103000 UTC
Lat : 18:47:10 N Lon : 148:20:16 W


CI# /Pressure/ Vmax
2.6 /1005.0mb/ 37.0kt


Final T# Adj T# Raw T#
2.1 2.1 2.1

Center Temp : -17.1C Cloud Region Temp : -17.3C

Scene Type : CURVED BAND with 0.38 ARC in DK GRAY
Maximum CURVED BAND with 0.72 ARC in DK GRAY
at Lat: 19:10:48 N Lon: 148:07:48 W

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : EAST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : FLAG

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 65km
- Environmental MSLP : 1012mb

Satellite Name : GOES15
Satellite Viewing Angle : 26.8 degrees




Kinda surprised recon is going ahead on this. As Don king would say, Only in America

[Kingarabian]

It looked just as bad yesterday. Durinal episodes throughout the day have a big effect on it.

[tolakram]

live ir loop

http://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-W%20PACUS&lat=19&lon=-150&info=ir&zoom=1&width=1000&height=800&type=Animation&quality=85&palette=ir1.pal&numframes=8

MLC looks well east of what may be the LLC.

[tolakram]

Latest shear map

[stormwise]

http://www.meteoearth.com/#/,235.60,18. ... 1469190191

EC model you can measure wind speed and hpa only good for 24hrs. Click on 3d to square the map up, will be interesting to see if it matches the recon data when it comes in.

[cycloneye]

 https://twitter.com/philklotzbach/status/756476792479752193

[Yellow Evan]

Likely generous.

Code: Select all

                    * EAST PACIFIC SHIPS INTENSITY FORECAST          *
                    * IR SAT DATA AVAILABLE,       OHC AVAILABLE     *
                    *  DARBY       EP052016  07/22/16  12 UTC        *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    50    47    44    41    40    38    33    27    22    18    16    16    17
V (KT) LAND       50    47    44    41    40    38    33    29    24    20    18    18    19
V (KT) LGEM       50    47    44    42    40    37    34    32    29    27    25    23    23
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP

SHEAR (KT)        14    14    10     7     8     9    20    26    32    25    17    12    13
SHEAR ADJ (KT)     4     2     2     5     6     3     3     2    -3    -4     0    -2    -1
SHEAR DIR        242   261   284   280   268   246   242   236   246   243   241   254   245
SST (C)         26.4  26.5  26.5  26.5  26.5  26.5  26.5  26.3  26.1  25.8  25.5  24.8  24.0
POT. INT. (KT)   127   128   128   129   128   128   128   126   124   120   118   111   103
200 MB T (C)   -52.8 -53.2 -53.3 -53.2 -53.6 -53.8 -54.1 -54.5 -55.1 -55.3 -55.2 -55.3 -55.4
200 MB VXT (C)   0.4   0.3   0.2   0.2   0.3   0.2   0.1   0.3   0.5   0.3   0.1   0.3   0.1
TH_E DEV (C)       6     6     6     7     7     7     7     7     7     7     7     6     5
700-500 MB RH     33    35    38    38    38    39    40    43    42    42    43    42    40
MODEL VTX (KT)    16    17    17    15    15    14    13    10     9     7     5     4     2
850 MB ENV VOR    24    25    22    19    13    17     9    15    18     4   -22   -59   -80
200 MB DIV       -11   -26   -24   -24    -5     2    16     1   -26   -21   -13     0    11
700-850 TADV       3     3     3     2     2     2     7     9     7    10     6    14     8
LAND (KM)        648   550   452   344   237    63    26    49    91   166   302   523   787
LAT (DEG N)     18.6  18.6  18.6  18.8  19.0  19.6  20.4  21.4  22.5  23.7  24.9  26.8  29.1
LONG(DEG W)    148.7 149.7 150.6 151.6 152.6 154.2 155.5 156.9 158.2 159.3 160.0 160.7 161.4
STM SPEED (KT)     9     9     9    10     9     8     8     8     8     7     9    11    12
HEAT CONTENT       3     5     6     6     7     9     7     4     1     0     0     0     0

  FORECAST TRACK FROM OFCI      INITIAL HEADING/SPEED (DEG/KT):265/  9      CX,CY:  -8/  0
  T-12 MAX WIND:  55            PRESSURE OF STEERING LEVEL (MB):  660  (MEAN=586)
  GOES IR BRIGHTNESS TEMP. STD DEV.  50-200 KM RAD:  16.0 (MEAN=14.5)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  24.0 (MEAN=65.0)
  PRELIM RI PROB (DV .GE. 30 KT IN 24 HR):            0.2

                        INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
                         6   12   18   24   36   48   60   72   84   96  108  120
                        ----------------------------------------------------------
  SAMPLE MEAN CHANGE     0.   0.   1.   1.   1.   1.   1.   1.   0.  -1.  -1.  -2.
  SST POTENTIAL          0.   1.   2.   2.   3.   4.   5.   5.   5.   5.   4.   3.
  VERTICAL SHEAR MAG     0.   0.   1.   1.   3.   2.  -1.  -6. -10. -13. -13. -13.
  VERTICAL SHEAR ADJ     0.   0.  -1.  -1.  -2.  -2.  -2.  -1.  -1.   0.   0.   0.
  VERTICAL SHEAR DIR     0.  -1.  -1.  -2.  -3.  -3.  -3.  -3.  -2.   0.   1.   3.
  PERSISTENCE           -1.  -2.  -3.  -3.  -3.  -3.  -2.  -1.  -1.  -1.   0.   1.
  200/250 MB TEMP.       0.   0.   0.   1.   2.   2.   3.   3.   4.   4.   4.   4.
  THETA_E EXCESS         0.   0.   0.   0.   0.   0.   1.   1.   1.   1.   1.   0.
  700-500 MB RH          0.  -1.  -1.  -2.  -2.  -3.  -4.  -5.  -6.  -6.  -7.  -7.
  MODEL VTX TENDENCY     0.   0.  -1.  -1.  -2.  -5.  -8. -10. -13. -14. -16. -16.
  850 MB ENV VORTICITY   0.   0.   0.   0.   0.   0.   0.   0.   0.   1.   1.   2.
  200 MB DIVERGENCE      0.  -1.  -2.  -2.  -3.  -4.  -4.  -4.  -5.  -5.  -4.  -3.
  850-700 T ADVEC        0.   0.   0.   0.   0.   0.   1.   1.   1.   2.   2.   3.
  ZONAL STORM MOTION     0.   0.   0.   0.   1.   1.   1.   1.   0.   0.   0.   0.
  STEERING LEVEL PRES    0.   0.   0.   1.   1.   1.   1.   1.   1.   2.   2.   2.
  DAYS FROM CLIM. PEAK   0.   0.   0.   0.   0.   0.   0.   0.   0.  -1.  -1.  -1.
  GOES PREDICTORS       -1.  -3.  -3.  -4.  -5.  -7.  -8.  -8.  -7.  -7.  -8.  -8.
  OCEAN HEAT CONTENT     0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.   0.   0.   0.
                        ----------------------------------------------------------
  TOTAL CHANGE          -3.  -6.  -9. -10. -12. -17. -23. -28. -32. -34. -34. -33.

                CURRENT MAX WIND (KT):   50. LAT, LON:   18.6   148.7

      ** 2015 E. Pacific RI INDEX EP052016 DARBY      07/22/16  12 UTC **
 (SHIPS-RII PREDICTOR TABLE for 30 KT OR MOREMAXIMUM WIND INCREASE IN NEXT 24-h)
 
     Predictor             Value   RI Predictor Range  Scaled Value(0-1) % Contribution
 12 HR PERSISTENCE (KT):    -5.0     -22.0  to   38.5       0.28         999.0
 POT = MPI-VMAX (KT)   :    78.1      40.3  to  144.5       0.36         999.0
 HEAT CONTENT (KJ/cm2) :     5.4       0.0  to   75.9       0.07         999.0
 STD DEV OF IR BR TEMP :    16.0      38.9  to    2.1       0.62         999.0
 850-200 MB SHEAR (KT) :    10.8      18.9  to    1.4       0.46         999.0
 MAXIMUM WIND (kt)     :    50.0      22.5  to  132.0       0.77         999.0
 D200 (10**7s-1)       :   -18.0     -11.0  to  135.3       0.00           0.0
 BL DRY-AIR FLUX (w/m2):   421.8     638.0  to  -68.2       0.31         999.0
 2nd PC OF IR BR TEMP  :    -0.5       2.1  to   -1.7       0.69         999.0
 % AREA WITH TPW <45 mm:    23.1      81.4  to    0.0       0.72         999.0
 
 SHIPS Prob RI for 20kt/ 12hr RI threshold=   4% is   0.6 times sample mean ( 6.3%)
 SHIPS Prob RI for 25kt/ 24hr RI threshold=   0% is   0.0 times sample mean (12.9%)
 SHIPS Prob RI for 30kt/ 24hr RI threshold=   0% is   0.0 times sample mean ( 8.6%)
 SHIPS Prob RI for 35kt/ 24hr RI threshold=   0% is   0.0 times sample mean ( 5.8%)
 SHIPS Prob RI for 40kt/ 24hr RI threshold=   0% is   0.0 times sample mean ( 4.1%)
 SHIPS Prob RI for 45kt/ 36hr RI threshold=   0% is   0.0 times sample mean ( 7.1%)
 SHIPS Prob RI for 55kt/ 48hr RI threshold=   0% is   0.0 times sample mean ( 5.9%)
 
 Matrix of RI probabilities
 ---------------------------------------------------------------------
  RI (kt / h)  | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48
 ---------------------------------------------------------------------
   SHIPS-RII:     3.6%    0.0%    0.0%    0.0%    0.0%    0.0%    0.0%
    Logistic:     0.1%    0.3%    0.3%    0.0%    0.0%    0.1%    0.0%
    Bayesian:     0.0%    0.1%    0.0%    0.0%    0.0%    0.0%    0.0%
   Consensus:     1.3%    0.1%    0.1%    0.0%    0.0%    0.0%    0.0%

   ##         ANNULAR HURRICANE INDEX (AHI) EP052016 DARBY      07/22/16  12 UTC         ##
   ## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3                          ##
   ## AHI=  0   (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

[Yellow Evan]

000
NOUS42 KNHC 221255
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0900 AM EDT FRI 22 JULY 2016
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 23/1100Z TO 24/1100Z JULY 2016
TCPOD NUMBER.....16-057

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
1. TROPICAL STORM DARBY
FLIGHT ONE - TEAL 78 FLIGHT TWO - TEAL 76
A. 23/1800Z,24/0000Z A. 24/0600Z,1200Z
B. AFXXX 0305E DARBY B AFXXX 0405E DARBY
C. 23/1600Z C. 24/0500Z
D. 19.4N 153.1W D. 20.1N 154.7W
E. 23/1730Z TO 24/0000Z E. 24/0530Z TO 24/1200Z
F. SFC TO 10,000 FT F. SFC TO 10,000 FT

2. SUCCEEDING DAY OUTLOOK: CONTINUE 6-HRLY FIXES WHILE
DARBY REMAINS A THREAT.

[cycloneye]

TROPICAL STORM DARBY DISCUSSION NUMBER 44
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP052016
500 AM HST FRI JUL 22 2016

After decreasing through much of the night, deep convection around
Darby has once again flared along the northern quadrant. Exposed
low cloud bands across the southern semicircle show a reasonably
well organized system, with good outflow to the northeast.
Objective Dvorak satellite intensity estimates remain unchanged at
3.0/45 knots from all three analysis centers (HFO, JTWC and SAB).
An 0718 UTC QSCAT pass showed a broad swath of 45 knot winds across
the northern semicircle, with a small handful of 50 knot barbs
thrown in. We will drop the initial intensity to 50 kt for this
advisory based on this pass and eagerly await 53rd Weather
Reconnaissance Squadron data, scheduled for arrival later this
morning, to clarify Darby intensity.

Initial motion is 270/10 kt, partially derived by rebesting the
previous three best track points. While last evening's QSCAT pass
depicted a center likely too far south, the overall impression from
a growing body of microwave imagery was that Darby was actually
several tenths of a degree south of where we though it was. Darby
was relocated for this advisory. A 1223 UTC SSMI pass, received too
late to use for this advisory, hints that Darby may need to be
relocated westward later. Track guidance is tightly packed depicting
a gently curving path along or just east of the Hawaiian Islands
between 36 and 72 hours. The exception is GFDL, which wants to
divert Darby almost due northward beyond 24 hours. Our forecast
track fits in the envelope, closely following TVCN consensus.
Adjustments were made to account for relocation. However, that
portion of the track closest to the Hawaiian Islands changed very
little. Darby continues to move along the southern flank of a ridge
centered north of Hawaii and will continue to do so through 36
hours. Afterwards, a deep low will dig south and weaken the ridge,
slowing this system down and allowing Darby to curve gently
northwestward from 36 to 72 hours, then northward beyond 72 hours.

Intensity guidance varies from SHIPS, which rapidly weakens Darby
after 48 hours, to GHMI, which maintains current strength
throughout. The effects of shear and slightly warmer SSTS are
expected to essentially cancel each other out through 48 hours, with
the weakening effects of shear becoming dominant afterwards as Darby
gains latitude. Any weakening effects that land interaction would
have on Darby intensity have been ignored so far. Our intensity
forecast depicts Darby as weaker at all tau than previous
advisories, with this system finally becoming a depression on day
5.

Interests outside of the watch and warning areas in the Hawaiian
islands should monitor the progress of Darby, as it could eventually
have impacts on all islands through early next week. Remember, it is
important not to focus too closely on the exact track and intensity
forecasts because the average track error 72 hours out is near 100
miles, while the average intensity error is about 15 kt. In
addition, the hazards of a tropical cyclone can extend over a broad
area well away from the center.

FORECAST POSITIONS AND MAX WINDS

INIT 22/1500Z 18.6N 149.2W 50 KT 60 MPH
12H 23/0000Z 18.7N 150.9W 45 KT 50 MPH
24H 23/1200Z 19.0N 152.8W 45 KT 50 MPH
36H 24/0000Z 19.7N 154.4W 45 KT 50 MPH
48H 24/1200Z 20.7N 155.7W 45 KT 50 MPH
72H 25/1200Z 23.0N 158.2W 40 KT 45 MPH
96H 26/1200Z 26.5N 160.5W 35 KT 40 MPH
120H 27/1200Z 31.3N 161.6W 30 KT 35 MPH

$$
Forecaster Powell

[Kingarabian]

CPHC seems to be not giving the Euro any consideration in its forecasts.

I'm expecting recon to find 45-50kts. I've seen such winds on worse looking storms.

[NDG]

Recon has taken off.