EPAC: HILDA- Post-Tropical

[Yellow Evan]

ADT's climbing:

2015AUG06 173000 2.7 1005.8 39.0 2.7 2.8 3.2 0.7T/6hr OFF OFF -65.06 -61.22 UNIFRM N/A -5.8 12.74 132.73 FCST GOES15 15.2
2015AUG06 180000 2.8 1004.6 41.0 2.8 2.8 3.3 0.7T/6hr OFF OFF -64.26 -60.29 UNIFRM N/A -5.8 12.75 132.80 FCST GOES15 15.2
2015AUG06 183000 2.8 1004.6 41.0 2.8 2.9 3.5 0.7T/6hr OFF OFF -64.26 -60.07 UNIFRM N/A -5.8 12.71 132.90 FCST GOES15 15.1

[Kingarabian]

Small storm so anything is possible:

[Yellow Evan]

Small ITCZ storms tend to have lots of ups and downs. This is likely an "up". But I will admit this has a good shot at becoming a solid Cat 1. Stronger still isn't something I'd bet one due to dry air, but if it can developed a structure that blocks out dry air well like what we've seen storms do furthe east in recent years, I guess a Cat 2/3 is possible.

[Kingarabian]

Small ITCZ storms tend to have lots of ups and downs. This is likely an "up". But I will admit this has a good shot at becoming a solid Cat 1. Stronger still isn't something I'd bet one due to dry air, but if it can developed a structure that blocks out dry air well like what we've seen storms do furthe east in recent years, I guess a Cat 2/3 is possible.

I kind of want to say the RI words right now, but after what we seen from Guillermo and no Kelvin wave to help, I'll lay off.

BUT if I had no choice and I had to make a bet, I would bet on this. Just because it's so small.

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]

Small ITCZ storms tend to have lots of ups and downs. This is likely an "up". But I will admit this has a good shot at becoming a solid Cat 1. Stronger still isn't something I'd bet one due to dry air, but if it can developed a structure that blocks out dry air well like what we've seen storms do furthe east in recent years, I guess a Cat 2/3 is possible.

I kind of want to say the RI words right now, but after what we seen from Guillermo and no Kelvin wave to help, I'll lay off.

BUT if I had no choice and I had to make a bet, I would bet on this. Just because it's so small.

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.

We're seeing what we typically see with intensifying tropical storms; fairly quick intensification. But yea, I wouldn't get on the RI bandwagon until we have a nice core (which to be fair, Hilda may be trying to build one now).

[Kingarabian]

Looks like it's starting:

[Yellow Evan]

Looks 50 knts based on that microwave.

[Yellow Evan]

Code: Select all

                    * EAST PACIFIC SHIPS INTENSITY FORECAST          *
                    * IR SAT DATA AVAILABLE,       OHC AVAILABLE     *
                    *  HILDA       EP102015  08/06/15  18 UTC        *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    45    50    54    59    62    68    71    71    71    67    65    62    58
V (KT) LAND       45    50    54    59    62    68    71    71    71    67    65    62    58
V (KT) LGE mod    45    51    57    62    67    75    81    83    81    77    72    69    63
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP

SHEAR (KT)         9     8     6     7     7     2     5     6    11    12    16    25    35
SHEAR ADJ (KT)     0     0     0    -1    -1    -1    -2     0    -5    -4    -4    -4    -6
SHEAR DIR         83    81    76    58    56    68   327   320   315   268   261   240   251
SST (C)         28.8  28.9  28.9  28.8  28.6  28.2  28.1  27.8  27.4  27.2  27.1  27.0  27.1
POT. INT. (KT)   153   154   154   153   151   147   146   143   137   134   133   133   135
200 MB T (C)   -51.7 -51.5 -51.6 -51.8 -51.9 -51.7 -52.1 -52.0 -52.5 -52.2 -52.6 -52.7 -53.8
TH_E DEV (C)       7     8     8     8     7     7     6     7     6     6     6     6     6
700-500 MB RH     67    66    65    63    63    62    57    56    52    52    57    60    58
MODEL VTX (KT)    10    10    10    10    10    10    10    10    11    12    13    14    15
850 MB ENV VOR    31    32    31    25    24    27    22    33    30    25     7     9    13
200 MB DIV         4    10    13    23    34    17    17    32    27    30    21    37    42
700-850 TADV       1     0     0    -2    -1     0     0     0     0    -1     1     2     5
LAND (KM)       2467  2363  2260  2140  2021  1801  1561  1318  1091   928   814   657   453
LAT (DEG N)     12.7  12.8  12.8  12.9  13.0  13.7  14.2  14.8  15.7  16.5  17.4  18.2  19.1
LONG(DEG W)    132.8 133.8 134.8 136.0 137.1 139.0 141.2 143.4 145.3 146.6 147.4 148.7 150.5
STM SPEED (KT)    11    10    11    11    10    11    11    11     9     7     6     9     9
HEAT CONTENT      33    26    22    23    22    10    10    13    15    19    20    24    18

[Kingarabian]

Looks 50 knts based on that microwave.

CIMSS AMSU: 998 hPa 48 knots Bias Corr: 0 (MW) Date: 08061437

http://tropic.ssec.wisc.edu/real-time/s ... 1510E.html

[Kingarabian]

[Yellow Evan]

Looks 50 knts based on that microwave.

CIMSS AMSU: 998 hPa 48 knots Bias Corr: 0 (MW) Date: 08061437

http://tropic.ssec.wisc.edu/real-time/s ... 1510E.html

Also worth noting that the storm's structure has improved since the AMSU pass as that was 4 hours old. Likely closer to 55 knots than 45 knots.

[Kingarabian]

Looks 50 knts based on that microwave.

CIMSS AMSU: 998 hPa 48 knots Bias Corr: 0 (MW) Date: 08061437

http://tropic.ssec.wisc.edu/real-time/s ... 1510E.html

Also worth noting that the storm's structure has improved since the AMSU pass as that was 4 hours old. Likely closer to 55 knots than 45 knots.

I'd go with 60kts but I doubt the NHC would. If they do, then it RI'd.

[Alyono]

had 45 kts for our 21Z advisory. had to rewrite it based upon microwave imagery

[Kingarabian]

had 45 kts for our 21Z advisory. had to rewrite it based upon microwave imagery

What do you have now?

[Yellow Evan]

[Kingarabian]

Basically all the global models except for the GFS are recurving this just before it reaches the Big Island of Hawaii. Let's see if the GFS follow suit @ 18z.

[Yellow Evan]

Levi Cowan ‏@TropicalTidbits 44m44 minutes ago

@EricBlake12 Small fist of fury under light winds aloft looks poised for some serious RI.

Robert Ballard ‏@firebomb56 44m44 minutes ago

@TropicalTidbits @EricBlake12 We will destroy your puny TC in the cPac faster than Philly destroyed #hitchBOT. #hiwx

[WeatherGuesser]

Hawaii luck is eventually going to run out. Not saying Hilda is going to be the one.

Keep shooting at the same target, you're bound to hit it once in a while, even from long distances.

[Alyono]

had 45 kts for our 21Z advisory. had to rewrite it based upon microwave imagery

What do you have now?

I went 50 kts

[cycloneye]

TROPICAL STORM HILDA DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP102015
200 PM PDT THU AUG 06 2015

Hilda's cloud pattern has rapidly increased in organization during
the past 12 hours. Conventional satellite imagery reveals a tiny
tropical cyclone with a nearly symmetric dense overcast and a
prominent band over the northern half of the circulation. A 1503
UTC Windsat pass showed a closed low-level ring of convection,
suggesting that the inner core of the tropical cyclone is already
well established. The initial intensity estimate is raised to 50 kt
in best agreement with an earlier AMSU pass.

The initial motion has been due west or 270/11. Nothing has
changed regarding the forecast philosophy in the previous advisory.
Hilda should continue moving westward and then turn west-
northwestward in about 36 hours as it nears the western periphery of
a subtropical ridge to its north. The cyclone should begin to
respond to a weakness in the ridge located to the east of the
Hawaiian Islands and turn northwestward at a significantly reduced
forward speed by 96 hours. The official track forecast has been
shifted significantly to the left during the first 48 hours but
still lies on the right side of the guidance envelope. The track
forecast after 48 hours is also left of the previous forecast but
is closer to the multi-model consensus late in the forecast period.

There are no obvious obstacles to additional intensification in the
short term, except for somewhat drier and more stable air mass to
the north and west of the cyclone. Given Hilda's small size, it is
assumed that the entrainment of this air is not likely to be an
inhibitor. The SHIPS model output indicates less conducive
thermodynamic variables in 2 to 3 days which should halt any further
intensification. Once the cyclone gains enough latitude in the
central Pacific after 72 hours, increasing southwesterly shear
associated with a mid- to upper-level trough near the longitude of
Hawaii should result in weakening. In fact, the shear could be
strong enough late in the period to cause a decoupling of the
cyclone as depicted in global model fields. The new intensity
forecast is boosted much higher in the short term to account for the
current strengthening trend and is closest to the LGEM. The
intensity forecast is near or below the multi-model consensus after
72 hours to emphasize the weakening expected at that time.


FORECAST POSITIONS AND MAX WINDS

INIT 06/2100Z 12.7N 133.4W 50 KT 60 MPH
12H 07/0600Z 12.6N 135.1W 55 KT 65 MPH
24H 07/1800Z 12.7N 137.4W 65 KT 75 MPH
36H 08/0600Z 13.1N 139.5W 70 KT 80 MPH
48H 08/1800Z 13.7N 141.6W 75 KT 85 MPH
72H 09/1800Z 15.5N 145.5W 70 KT 80 MPH
96H 10/1800Z 17.2N 147.9W 60 KT 70 MPH
120H 11/1800Z 18.5N 150.0W 45 KT 50 MPH

$$
Forecaster Kimberlain