EPAC: HILDA - Recon

[Yellow Evan]

000
URPN15 KNHC 100454
AF309 0110E HILDA HDOB 23 20150810
044430 1619N 14924W 6967 03186 0070 +110 +045 077044 044 018 000 00
044500 1617N 14923W 6962 03194 0075 +106 +048 075044 045 017 001 00
044530 1616N 14922W 6962 03191 0070 +108 +045 070043 044 017 001 00
044600 1615N 14921W 6967 03185 0067 +110 +046 070047 048 020 001 00
044630 1614N 14920W 6963 03191 0068 +110 +045 072046 048 021 001 00
044700 1613N 14919W 6958 03197 0071 +110 +041 070046 047 023 002 00
044730 1612N 14917W 6966 03189 0071 +110 +040 069045 046 016 002 00
044800 1611N 14916W 6963 03184 0060 +111 +037 068045 047 021 004 00
044830 1610N 14915W 6966 03178 0055 +113 +034 069048 048 022 001 00
044900 1608N 14914W 6963 03180 0054 +113 +035 066049 049 022 000 00
044930 1607N 14913W 6962 03180 0056 +111 +039 065048 049 024 004 00
045000 1606N 14911W 6962 03177 0054 +110 +044 064047 049 024 004 00
045030 1605N 14910W 6963 03174 0057 +105 +046 063047 048 024 001 00
045100 1604N 14909W 6962 03173 0059 +097 +059 063048 048 022 001 03
045130 1603N 14908W 6965 03167 0061 +095 +065 062049 049 025 001 03
045200 1602N 14907W 6962 03169 0063 +091 +069 061050 051 024 002 00
045230 1600N 14905W 6963 03163 0063 +090 +070 059051 051 027 001 00
045300 1559N 14904W 6964 03161 0065 +085 +077 059052 053 029 002 00
045330 1558N 14903W 6967 03155 0061 +083 +075 060052 054 030 002 01
045400 1557N 14902W 6957 03161 0072 +085 //// 064052 053 031 006 01
$$

[Chris_in_Tampa]

[Yellow Evan]

With these pressures on the NW side, the winds are much stronger this time around than the SW side. Then again this is the side of the deepest convection.


000
URPN15 KNHC 100504
AF309 0110E HILDA HDOB 24 20150810
045430 1556N 14901W 6968 03145 0063 +085 //// 065055 056 031 006 01
045500 1555N 14900W 6961 03152 0036 +095 +080 064056 057 029 004 00
045530 1554N 14858W 6962 03150 0039 +092 +089 063056 058 032 006 00
045600 1552N 14857W 6966 03146 0058 +090 +090 060057 057 038 007 00
045630 1551N 14856W 6963 03166 0064 +091 +088 056056 057 040 008 00
045700 1550N 14855W 6963 03147 0032 +097 +083 051053 056 043 007 00
045730 1549N 14854W 6965 03141 0012 +110 +080 051054 055 048 006 00
045800 1548N 14852W 6962 03141 0006 +112 +084 053053 055 048 007 00
045830 1546N 14851W 6962 03137 0001 +111 +088 050043 052 050 008 00
045900 1545N 14850W 6958 03140 0023 +098 +098 051042 043 052 009 00
045930 1544N 14848W 6969 03126 0020 +103 +103 058047 048 051 010 00
050000 1543N 14847W 6962 03126 0004 +104 +104 065051 052 051 007 00
050030 1542N 14846W 6965 03115 0010 +102 //// 065056 059 050 011 01
050100 1540N 14845W 6957 03112 0014 +102 +102 065062 064 053 012 00
050130 1539N 14844W 6965 03089 9968 +100 //// 064067 070 056 006 01
050200 1537N 14844W 6957 03079 9962 +103 +103 058070 077 062 017 03
050230 1536N 14843W 6970 03049 9940 +108 +108 057073 080 070 042 00
050300 1534N 14842W 6953 03025 9898 +117 +117 057084 087 079 038 00
050330 1533N 14841W 6973 02961 9843 +124 +124 044066 079 079 040 00
050400 1531N 14840W 6954 02969 9754 +150 +132 041042 061 084 023 03
$$
;

[Chris_in_Tampa]

In that last ob:

Lowest Extrapolated Sfc. Pressure: 975.4 mb (at end)
Flight Level Wind (30 sec. Avg.): 84 knots (1 minute from end)
Peak (10 sec. Avg.) Flight Level Wind: 87 knots (1 minute from end)
SFMR Peak (10s Avg.) Sfc. Wind: 79 knots (30 seconds from end. 84 knot at end was marked as suspect)

[Yellow Evan]

000
URPN15 KNHC 100514
AF309 0110E HILDA HDOB 25 20150810
050430 1530N 14839W 6973 02932 9730 +160 +122 035018 034 042 005 00
050500 1528N 14837W 6960 02943 9718 +170 +104 239001 011 016 002 00
050530 1527N 14836W 6967 02939 9724 +170 +094 233019 022 020 003 03
050600 1526N 14834W 6955 02969 9737 +169 +094 237043 055 047 001 00
050630 1525N 14833W 6948 03004 9763 +172 +071 233072 076 067 002 03
050700 1524N 14831W 6982 02986 9802 +165 +068 231075 078 075 001 00
050730 1523N 14830W 6951 03059 9859 +142 +089 230074 076 069 002 00
050800 1521N 14829W 6965 03062 9904 +124 +090 225071 073 064 003 00
050830 1520N 14828W 6965 03077 9937 +114 +081 217066 070 059 003 00
050900 1519N 14827W 6959 03101 9957 +109 +092 213058 065 053 004 01
050930 1518N 14825W 6968 03104 9977 +107 +086 207055 056 050 003 00
051000 1517N 14824W 6961 03121 9982 +108 +092 205051 055 047 002 00
051030 1515N 14823W 6959 03127 0018 +101 //// 206048 049 046 005 01
051100 1514N 14822W 6967 03122 9996 +108 +100 208044 046 045 005 00
051130 1513N 14821W 6967 03130 0007 +106 +101 209045 045 042 005 00
051200 1512N 14820W 6961 03141 0022 +111 //// 215044 045 039 005 01
051230 1511N 14818W 6965 03138 0038 +105 //// 216039 043 037 005 01
051300 1509N 14817W 6966 03139 0060 +105 +105 213036 039 036 007 00
051330 1508N 14816W 6974 03130 0075 +097 +097 197040 041 035 011 00
051400 1507N 14815W 6959 03155 0076 +094 +094 195039 041 033 008 00
$$
;

[Chris_in_Tampa]

[Chris_in_Tampa]

NW to SE pass:

Lowest Extrapolated Sfc. Pressure: 971.8 mb
Flight Level Wind (30 sec. Avg.): 84 knots
Peak (10 sec. Avg.) Flight Level Wind: 87 knots
SFMR Peak (10s Avg.) Sfc. Wind: 79 knots

[Chris_in_Tampa]

976mb, 15 knots of surface wind

UZPN13 KNHC 100518
XXAA 60057 99155 71486 05158 99976 26808 09015 00719 ///// /////
92472 24008 12005 85213 21827 11509 70895 18058 19506 88999 77999
31313 09608 80505
61616 AF309 0110E HILDA OB 13
62626 CENTER MBL WND 12510 AEV 07775 DLM WND 13006 975696 WL150 1
1514 084 REL 1547N14861W 050507 SPG 1547N14862W 050927 =
XXBB 60058 99155 71486 05158 00976 26808 11850 21827 22707 19459
33696 17458
21212 00976 09015 11970 11515 22961 12514 33923 12504 44905 10507
55892 11503 66850 11509 77832 16010 88815 12510 99696 20507
31313 09608 80505
61616 AF309 0110E HILDA OB 13
62626 CENTER MBL WND 12510 AEV 07775 DLM WND 13006 975696 WL150 1
1514 084 REL 1547N14861W 050507 SPG 1547N14862W 050927 =
;

[Kingarabian]

Looks like surface wind is a significant variable in recon readings.

Can someone explain how it works?

[Chris_in_Tampa]

[Chris_in_Tampa]

Looks like surface wind is a significant variable in recon readings.

Can someone explain how it works?

From the plane they estimate it with the SFMR instrument. It takes a 10 second estimate.

http://www.403wg.afrc.af.mil/library/fa ... sp?id=8314
http://www.aoml.noaa.gov/hrd/project2005/sfmr.html

It's not really measured I would say like that AF article says. I would consider a sonde a measurement and the SFMR an estimate. Heavy rain, which is also estimated, could also impact the wind reading.

Highest surface wind should be near the center of the storm. If it is way out in the bands, then it is probably not representative in a tropical system. (such as it measured a gust in a thunderstorm out in the outer bands)

A sonde is a momentary gust. The sonde is falling in the atmosphere, with a little parachute.

http://www.aoc.noaa.gov/instrumentation.htm
https://www.eol.ucar.edu/isf/facilities/dropsonde/
http://scied.ucar.edu/dropsonde-animation-noaa

So the wind speed it measures is very brief since it can't stay at a level, it is always falling. I think it is about 0.5 seconds for current sondes, but I'm not really sure. Looking at the very raw sonde data, which usually seems to be every half a second, I think it means that is likely how long the reading is. However, the data as it comes across in a message like the UZPN13 one's above, have come through a program called ASPEN which may average the half second data out over a longer period near the level it says. I just don't know.

[Chris_in_Tampa]

And keep in mind that advisory data from the NHC and CPHC is for 1 minute sustained surface wind at sea level. (or maybe it is 10 meters above sea level) The gusts will be higher, and those are in the forecast advisory.

For example, at 5pm HST the forecast advisory had "MAX SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT."

So we are seeing higher wind gusts than the sustained figure from the dropsonde and a bit higher from the SFMR instrument. But, are they actually perhaps sustained at some of those higher readings, or are they just sampling some of the higher gusts they know are out there? (I don't know.) In such a small storm, it might be very easy for the aircraft to miss some of the higher winds.

Higher elevations will have higher sustained winds, but that is not contained in what you see in the forecast. They might mention it elsewhere, like the discussion for example. So the mountains on the big island could see some strong winds, especially gusts.

[Chris_in_Tampa]

URPN12 KNHC 100537
VORTEX DATA MESSAGE EP102015
A. 10/05:05:00Z
B. 15 deg 29 min N
148 deg 38 min W
C. 700 mb 2894 m
D. 79 kt
E. 321 deg 7 nm
F. 057 deg 87 kt
G. 321 deg 7 nm
H. 976 mb
I. 10 C / 3051 m
J. 18 C / 3056 m
K. 9 C / NA
L. OPEN SE, NW
M. CO3-10
N. 12345 / 7
O. 0.02 / 1 nm
P. AF309 0110E HILDA OB 11
MAX FL WIND 96 KT 072 / 13 NM 03:48:00Z
CNTR DROPSONDE SFC WIND 090 / 15 KT

[Chris_in_Tampa]

Looks like the final pass is upcoming, from East to West. Maybe they will sample some of that intense convection too.

Through 5:44Z:

[Kingarabian]

Thank you, Chris. I'll read up on those articles you posted.

[Chris_in_Tampa]

Here is the company that actually makes those dropsondes:
http://www.vaisala.com/en/products/soun ... fault.aspx

I just did a Google search, some of those sites may be more technical than you want. Some of the information is just so old, but I guess it still applies.

URPN15 KNHC 100555
AF309 0110E HILDA HDOB 29 20150810
054430 1530N 14718W 6965 03180 0071 +095 +086 154034 034 008 001 03
054500 1530N 14719W 6963 03183 0071 +096 +085 150034 034 012 000 00
054530 1530N 14721W 6963 03180 0065 +100 +079 149034 034 013 000 03
054600 1530N 14723W 6965 03177 0063 +100 +083 147033 034 013 001 00
054630 1530N 14725W 6965 03179 0063 +101 +078 150034 035 013 000 00
054700 1530N 14727W 6963 03179 0066 +097 +086 153034 035 013 001 00
054730 1530N 14729W 6963 03179 0075 +090 +085 150035 036 016 001 01
054800 1530N 14731W 6963 03180 0072 +092 +076 152035 036 021 001 00
054830 1530N 14733W 6965 03174 0072 +091 +082 158036 036 022 001 00
054900 1530N 14735W 6961 03177 0066 +095 +085 159038 038 020 002 00
054930 1530N 14737W 6967 03172 0067 +095 +085 159038 038 024 002 03
055000 1530N 14739W 6963 03177 0072 +093 //// 162038 038 025 002 01
055030 1530N 14741W 6965 03173 //// +089 //// 161039 039 028 004 01
055100 1530N 14743W 6962 03177 0071 +096 +096 157039 041 027 006 00
055130 1530N 14745W 6964 03173 0068 +092 //// 155040 042 028 004 01
055200 1530N 14747W 6959 03178 //// +091 //// 154041 042 027 003 01
055230 1530N 14749W 6965 03171 0061 +095 +087 152042 043 028 001 00
055300 1530N 14751W 6959 03175 0059 +095 +086 152044 045 026 003 00
055330 1530N 14753W 6965 03174 0086 +089 //// 147046 047 029 004 01
055400 1530N 14755W 6965 03216 0140 +087 //// 142050 051 037 012 01
$$
;

[Chris_in_Tampa]

[Chris_in_Tampa]

URPN15 KNHC 100603
AF309 0110E HILDA HDOB 30 20150810
055430 1530N 14757W 6967 03252 0203 +088 +088 145047 050 038 012 00
055500 1530N 14759W 6957 03179 0126 +090 +090 151045 046 038 011 00
055530 1530N 14801W 6960 03171 0111 +092 +092 154050 053 040 010 00
055600 1530N 14803W 6969 03157 0084 +083 //// 164050 051 040 010 01
055630 1530N 14804W 6961 03166 0059 +089 +087 164048 049 032 004 01
055700 1530N 14806W 6958 03166 //// +085 //// 164048 049 033 003 01
055730 1530N 14808W 6962 03157 0059 +094 //// 160049 049 034 003 01
055800 1530N 14810W 6967 03147 0071 +088 //// 160049 050 032 005 01
055830 1530N 14812W 6963 03147 0049 +094 //// 163048 050 032 005 01
055900 1530N 14814W 6960 03146 0063 +099 +099 164044 048 033 007 00
055930 1530N 14816W 6964 03140 //// +086 //// 169045 046 037 003 01
060000 1530N 14818W 6960 03140 //// +091 //// 176050 052 038 005 01
060030 1530N 14820W 6963 03133 0031 +106 //// 175053 055 043 006 01
060100 1530N 14821W 6967 03124 0027 +107 +107 168052 054 046 009 00
060130 1530N 14823W 6968 03121 0030 +108 +108 174053 054 046 009 00
060200 1530N 14825W 6949 03135 0018 +113 +113 172058 060 050 011 00
060230 1530N 14827W 6973 03096 9992 +108 //// 170061 063 050 009 01
060300 1530N 14829W 6959 03106 9964 +107 +102 172064 064 053 005 00
060330 1530N 14831W 6963 03090 9948 +110 +095 175067 068 054 007 00
060400 1530N 14832W 6950 03091 9939 +104 +096 174073 075 060 006 00
$$
;

[Chris_in_Tampa]

URPN15 KNHC 100614
AF309 0110E HILDA HDOB 31 20150810
060430 1530N 14834W 6977 03043 9918 +103 +100 182075 077 065 003 01
060500 1530N 14836W 6951 03051 9875 +121 +091 196076 078 067 000 03
060530 1530N 14837W 6963 03006 9816 +145 +098 200071 078 071 001 00
060600 1531N 14839W 6958 02981 9783 +143 +114 200057 065 075 001 00
060630 1531N 14841W 6959 02955 9752 +151 +107 207025 046 072 003 03
060700 1531N 14842W 6968 02942 9739 +157 +104 198012 017 036 001 00
060730 1532N 14844W 6956 02950 9723 +166 +097 060005 010 009 002 03
060800 1532N 14846W 6967 02939 9722 +171 +096 026020 027 013 001 00
060830 1532N 14848W 6963 02960 9747 +161 +107 010030 031 035 001 03
060900 1532N 14850W 6957 02991 9750 +184 +081 350061 070 069 021 00
060930 1532N 14852W 7002 02959 9789 +168 +100 359061 067 072 024 00
061000 1532N 14853W 6967 03029 9849 +144 +105 004065 068 072 024 00
061030 1532N 14855W 6987 03038 9903 +126 +103 009063 067 067 013 00
061100 1532N 14857W 6975 03068 9924 +125 +103 004051 058 060 004 00
061130 1532N 14859W 6966 03094 9946 +117 +108 000049 050 059 005 00
061200 1532N 14901W 6960 03110 9958 +116 +108 006055 056 053 007 00
061230 1532N 14903W 6961 03118 9980 +109 +102 011053 056 048 007 00
061300 1532N 14903W 6961 03118 0002 +097 //// 014048 052 042 007 01
061330 1532N 14906W 6969 03118 0027 +099 //// 017045 046 036 004 01
061400 1532N 14908W 6966 03127 0019 +104 +104 020046 046 033 005 00
$$
;

[Chris_in_Tampa]