WPAC: HECTOR - Post-Tropical

[Eric Webb]

The intermediate advisory from the CPHC has knocked Hector all the way back to a 115 KT category 4 hurricane.

[NotSparta]

Structure looking pretty good, but EWRC is still ongoing

[cycloneye]

EP, 10, 2018080712, , BEST, 0, 160N, 1471W, 115, 947, HU

[Eric Webb]

 https://twitter.com/TropicalTidbits/status/1026833678180274186

[NotSparta]

Some dry air attempt to disrupt the core, but got kicked out by some new eyewall convection

[mrbagyo]

Behold, look at that solid ring - just like Irma (Northern sector looks pretty weak though)
Dry air lurks nearby.

[Eric Webb]

Hector definitely looks better on the latest dvorak images, we might be able to squeeze out another 10 KTS or so but this storm isn't too far from its maximum potential intensity, once he reaches 165W, SSTs will increase again and we might be able to make another run at a cat 5.

[Eric Webb]

Another HH plane just took off from Hawaii to investigate Hector, they should get into the storm around 1-130pm eastern, hopefully we don't lose communication with this one too.

[mrbagyo]

I'd bet they would find a high end cat 4 or a minimal 5.

[Yellow Evan]

WTPA41 PHFO 071501
TCDCP1

Hurricane Hector Discussion Number 29
NWS Central Pacific Hurricane Center Honolulu HI EP102018
500 AM HST Tue Aug 07 2018

The satellite presentation of Hector has degraded slightly since
the previous advisory, with cooling temperatures noted within the
slowly shrinking eye of the hurricane. Aircraft reconnaissance data
from the mission flown between 06Z and 12Z by the Air Force Reserve
53rd Weather Reconnaissance Squadron indicated that Hector was
weakening, confirming what was being seen in satellite imagery. The
last report from the overnight mission measured a surface wind of
107 knots in the northwest eye wall around 1030Z, on their way back
to Honolulu. The various subjective Dvorak current intensity
estimates from PHFO, SAB and JTWC came in at 6.5 (127 knots), while
the latest estimate using the Advanced Dvorak technique from
UW-CIMSS yielded 6.2 (120 knots). The initial intensity was weighted
equally between the various satellite estimates and the
observational data from the aircraft, taking into account that the
aircraft could have very easily under sampled the strongest winds
within the hurricane. As a result, the initial intensity with this
advisory is set at 115 knots with a motion remaining locked in at
280/14 knots.

The latest model guidance remains tightly clustered and brings
Hector just north of due west today. A building subtropical ridge
to the north of the Hawaiian Islands should then steer Hector
nearly due westward tonight through Thursday night. The system
should begin to bend back toward the west-northwest or northwest
Friday through Saturday as it rounds the southwest periphery of the
subtropical ridge and begins to be influenced by an upper level
trough setting up between 170W and the International Date Line. The
new official forecast track lies virtually on top of the previous
track and is very close to the model consensus. The forecast track
brings the center of Hector roughly 165 miles south of the
Big Island as a strong category 2 hurricane on Wednesday, and given
the proximity of the storm to the island, the Tropical Storm Watch
remains in effect.

Hector will remain in a favorable low shear environment through
Friday, before west-southwesterly shear increases on Saturday.
There are a couple factors that should lead to some gradual
weakening over the next couple of days however. The hurricane will
be traveling over marginal sea surface temperatures around 27C
through Wednesday night, before the SSTs increase slightly to around
28C to the south and west of the Hawaiian Islands Thursday through
Saturday. Additionally, very dry mid-level air will continue to
surround the storm through the forecast period, and this is should
lead to gradual weakening of the system over the next couple days.
The intensity of Hector is then expected to level off and perhaps
increase slightly by the 72 and 96 hour forecast points Thursday
through Friday as it encounters the higher SSTs. Some weakening
should then ensue on Saturday as Hector begins to feel increasing
west-southwesterly shear as it approaches the upper trough between
170W and the Date Line. The intensity forecast has been adjusted
slightly downward today through Wednesday night, then is nearly the
same as the previous forecast from Thursday through Saturday. This
is in line with the latest trends of the statistical and dynamical
models, but with more weight given to the dynamical models which
have been better performers recently.


FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 16.1N 147.8W 115 KT 130 MPH
12H 08/0000Z 16.3N 150.1W 110 KT 125 MPH
24H 08/1200Z 16.4N 153.1W 100 KT 115 MPH
36H 09/0000Z 16.5N 156.1W 95 KT 110 MPH
48H 09/1200Z 16.5N 159.2W 95 KT 110 MPH
72H 10/1200Z 17.0N 165.3W 100 KT 115 MPH
96H 11/1200Z 18.2N 170.6W 100 KT 115 MPH
120H 12/1200Z 20.0N 175.0W 95 KT 110 MPH

$$
Forecaster Jelsema

[Yellow Evan]

200
NOUS42 KNHC 071600
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1200 PM EDT TUE 07 AUGUST 2018
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 08/1100Z TO 09/1100Z AUGUST 2018
TCPOD NUMBER.....18-075

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

II. PACIFIC REQUIREMENTS
1. HURRICANE HECTOR
FLIGHT ONE -- TEAL 77
A. 08/1730Z,2330Z
B. AFXXX 0810E HECTOR
C. 08/1600Z
D. 16.4N 154.5W
E. 08/1700Z TO 08/2330Z
F. SFC TO 10,000 FT

FLIGHT TWO -- TEAL 78
A. 09/0530Z
B. AFXXX 0910E HECTOR
C. 09/0430Z
D. 16.5N 157.6W
E. 09/0500Z TO 09/0830Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

[Eric Webb]

Dvorak intensity estimates have risen significantly again, back up to ~125 KTS/T6.5. We'll see what recon finds here in a bit.

[hurricanes1234]

I wonder if he could make a second run at category 5 status.

[Ntxw]

Been awhile since we have seen a Hurricane look this good, this close to Hawaii

[Yellow Evan]

531
URPN15 KNHC 071725
AF309 0510E HECTOR HDOB 15 20180807
171600 1759N 15044W 4975 05919 0310 -052 -440 067036 038 /// /// 03
171630 1758N 15041W 5026 05840 0306 -052 -427 072032 035 /// /// 03
171700 1757N 15039W 5074 05767 0302 -051 -366 077030 031 /// /// 03
171730 1755N 15036W 5122 05690 0295 -046 -295 079031 031 /// /// 03
171800 1754N 15034W 5172 05614 0291 -042 -200 081031 031 /// /// 03
171830 1753N 15031W 5225 05533 0285 -034 -195 077029 031 /// /// 03
171900 1752N 15029W 5280 05449 0281 -027 -210 075029 030 /// /// 03
171930 1751N 15026W 5420 05247 0275 -019 -160 072027 029 /// /// 03
172000 1749N 15024W 5605 04979 0103 -006 -117 069029 030 /// /// 03
172030 1748N 15022W 5798 04706 0118 +001 -075 065029 030 016 000 00
172100 1747N 15019W 5997 04433 0121 +014 -054 056027 027 017 000 03
172130 1746N 15017W 6197 04167 0117 +034 -047 056028 029 018 000 00
172200 1745N 15015W 6397 03904 0108 +053 -032 058028 028 019 000 00
172230 1744N 15012W 6579 03673 0102 +069 -013 061029 029 019 000 03
172300 1743N 15010W 6770 03438 0107 +081 -006 063029 030 018 000 03
172330 1742N 15008W 6944 03217 0097 +093 +014 065030 030 019 000 00
172400 1741N 15006W 6967 03184 0088 +095 +030 065030 031 017 001 00
172430 1740N 15004W 6966 03187 0089 +095 +021 068032 033 015 001 00
172500 1739N 15002W 6967 03184 0084 +100 +014 066033 034 017 000 00
172530 1737N 14959W 6965 03188 0082 +100 +009 063033 033 016 000 03
$$

[Yellow Evan]

652
URPN15 KNHC 071735
AF309 0510E HECTOR HDOB 16 20180807
172600 1736N 14957W 6966 03184 0079 +102 +008 061032 033 019 000 00
172630 1734N 14956W 6968 03182 0083 +099 +015 063032 033 018 000 00
172700 1732N 14954W 6967 03182 0088 +095 +020 062032 032 019 000 00
172730 1731N 14952W 6967 03181 0079 +100 +018 059032 033 019 000 00
172800 1729N 14950W 6967 03179 0079 +099 +020 057034 034 018 000 00
172830 1727N 14948W 6967 03180 0078 +102 +010 056035 036 019 000 00
172900 1726N 14947W 6978 03168 0078 +102 +000 055035 036 020 000 00
172930 1724N 14945W 6979 03170 0081 +100 +006 056035 036 017 000 00
173000 1723N 14943W 6970 03180 0082 +099 +014 056034 035 018 000 00
173030 1721N 14942W 6970 03177 0082 +095 +018 055034 034 019 000 00
173100 1720N 14941W 6966 03182 0081 +096 +019 053035 036 019 000 00
173130 1719N 14939W 6966 03182 0081 +098 +021 050036 037 020 000 00
173200 1718N 14938W 6967 03179 0083 +095 +021 051036 037 020 000 03
173230 1716N 14937W 6968 03178 0083 +095 +025 055037 037 021 000 00
173300 1715N 14936W 6966 03178 0086 +091 +025 056036 037 022 000 00
173330 1714N 14934W 6967 03176 0087 +089 +027 058036 037 020 001 00
173400 1713N 14933W 6968 03173 0082 +092 +019 060036 037 020 000 00
173430 1712N 14932W 6967 03174 0080 +094 +014 059037 038 020 000 00
173500 1710N 14931W 6966 03174 0079 +095 +012 061039 039 020 000 03
173530 1709N 14929W 6967 03172 0081 +091 +015 059038 039 020 000 00
$$

[Kingarabian]

Last few frames show this still north of west. Maybe the CPHC should issue a TS warning just in case:

[Yellow Evan]

425
URPN15 KNHC 071745
AF309 0510E HECTOR HDOB 17 20180807
173600 1708N 14928W 6969 03169 0084 +091 -025 058039 039 022 000 00
173630 1707N 14927W 6967 03171 0090 +086 -026 056041 042 023 001 00
173700 1706N 14926W 6966 03172 0099 +075 -006 060042 043 023 001 00
173730 1704N 14924W 6967 03168 0096 +077 +006 061042 042 026 003 00
173800 1703N 14923W 6966 03168 0082 +087 +001 062042 043 026 004 00
173830 1702N 14922W 6969 03165 0084 +084 +014 064043 044 026 003 00
173900 1701N 14921W 6964 03168 0091 +076 +027 062045 047 025 003 00
173930 1700N 14919W 6961 03172 0075 +089 +005 060046 047 026 001 00
174000 1659N 14918W 6969 03162 0074 +090 -016 060050 051 025 000 00
174030 1657N 14917W 6967 03160 0073 +090 -030 060050 051 024 000 03
174100 1656N 14916W 6967 03160 0067 +090 -035 059049 050 024 001 00
174130 1655N 14915W 6966 03160 0070 +090 -037 058047 048 026 000 00
174200 1654N 14913W 6967 03157 0066 +091 -027 060047 047 028 001 03
174230 1653N 14912W 6963 03159 0086 +071 +004 059048 051 028 001 00
174300 1652N 14911W 6975 03144 0099 +063 -005 066048 050 030 005 03
174330 1650N 14910W 6962 03161 0069 +086 -008 064048 050 031 001 00
174400 1649N 14909W 6969 03150 0057 +095 -024 063051 052 030 001 00
174430 1648N 14907W 6965 03152 0059 +090 -034 062051 052 030 000 00
174500 1647N 14906W 6966 03149 0061 +090 -041 062052 053 031 000 03
174530 1646N 14905W 6970 03141 0056 +090 -038 058052 052 030 000 00
$$

[Yellow Evan]

856
URPN15 KNHC 071756
AF309 0510E HECTOR HDOB 18 20180807
174600 1645N 14904W 6966 03145 0054 +090 -026 057053 054 032 000 00
174630 1644N 14903W 6968 03141 0053 +090 -024 061055 055 032 000 00
174700 1642N 14901W 6965 03143 0054 +084 -006 055055 056 035 000 00
174730 1641N 14900W 6966 03137 0046 +089 -014 049054 056 034 001 00
174800 1640N 14859W 6970 03131 0046 +087 -018 049056 057 038 001 00
174830 1639N 14858W 6965 03132 0054 +076 -000 052057 059 039 001 03
174900 1638N 14856W 6968 03123 0037 +083 +016 052059 061 038 004 00
174930 1636N 14855W 6967 03122 0026 +090 +001 052062 064 039 001 00
175000 1635N 14854W 6968 03115 0020 +090 -016 052066 066 040 001 00
175030 1634N 14853W 6967 03112 0013 +095 -028 051067 067 041 001 00
175100 1633N 14852W 6967 03106 0005 +095 +004 052069 069 043 003 00
175130 1632N 14850W 6966 03101 9994 +096 +000 051069 069 045 002 00
175200 1631N 14849W 6969 03092 9995 +090 -005 049071 072 047 003 00
175230 1630N 14848W 6963 03090 9980 +096 -003 046073 074 050 003 00
175300 1628N 14847W 6969 03076 9969 +097 -006 043075 077 052 005 00
175330 1627N 14845W 6967 03067 9966 +090 +000 043079 080 054 008 00
175400 1626N 14844W 6965 03060 9959 +085 -003 043084 085 060 005 00
175430 1625N 14843W 6966 03043 9926 +098 +000 040088 089 063 005 00
175500 1623N 14842W 6963 03030 9920 +087 +004 037093 095 070 006 00
175530 1622N 14841W 6967 03003 9909 +074 +002 037100 105 076 009 00
$$

[storm_in_a_teacup]

Yeah, but it’s not surprising at all that it’s gone annular, since the majority of hurricanes develop annular characteristics in strictly 25-28C waters. I don’t see any reason why Hector would see any significant fluctuations in intensity over the next several days.

I also suspect that models are underestimating the mid-level ridge to the north, since Hectors outflow will likely enhance it, similar to Irma last year. You can only write equations for so many things that a model can handle.

Okay something that has been bothering me about the whole “annular” thing:
People say annular hurricanes are more stable in marginal conditions than the average hurricane, but if they typically are found in the self-same marginal conditions, are they annular before entering those conditions, and the survive for longer because of that; or are the marginal conditions actually causing the annular state?

...also hi. It’s been a while

No they aren’t annular before they develop annular characteristics. That’s ridiculous. Hurricanes generally develop annular characteristics in a specific environment, which is SST’s between 25-28C, light easterly upper level winds, and an anomalously cold temperatures in the upper troposphere. Conditions have to be just right, and that’s why they’re extremely rare.

My assumption is that the hurricane gains the annular structure as an adjustment to most efficiently operate its latent heat engine in that specific environment.

Okay...I was half asleep when posted my question so I wrote it very badly. I am aware that you cannot have an annular hurricane before it becomes annular by definition. I was just curious as to whether they become annular in morphology before they encountered the marginal conditions, and it was simply that the non-annular storms died off while the annular ones survived.

It’s clearly not the case, as you stated, but then that makes me wonder how the physics of the annular state works. After all a storm cannot “decide” to adopt the maximal efficiency state, so I wonder how that occurs. In astrophysics at least, it comes down usually to a balance between different forces, but that doesn’t necessarily lead to a high efficiency state.