Thursday Evening: Dorian is strengthening based on recon
Posted by Chris in Tampa on 8/29/2019, 9:27 pm
I'm done editing the post in place. I'll add a reply when I have some recon images created or some more significant ob occurs.

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Air Force Mission (at around 700mb level, 10,500 feet):

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NE Quadrant (1st pass into center, SW to NE quadrant):

Flight Level Wind (30 sec. Avg.): 84 knots (97 mph)
Peak (10 sec. Avg.) Flight Level Wind: 86 knots (99 mph)
SFMR Peak (10s Avg.) Sfc. Wind: Two 30 second readings missing. One suspect one was 101mph.

NW Quadrant (2nd pass into center, NW to SE quadrant)

Flight Level Wind (30 sec. Avg.): 73 knots (84.0 mph)
Peak (10 sec. Avg.) Flight Level Wind: 77 knots (88.6 mph)
SFMR Peak (10s Avg.) Sfc. Wind: One 30 second reading missing. 91 knots (105 mph) and was not marked as suspect.

Measured center pressure (9:09:59pm AST): 980mb with 18 knots of surface wind. That means a pressure of likely 979 or 978mb.

Vortex Message:

URNT12 KNHC 300133
VORTEX DATA MESSAGE AL052019
A. 30/01:05:30Z
B. 23.04 deg N 068.11 deg W
C. 700 mb 2933 m
D. 980 mb
E. 170 deg 18 kt
F. NA
G. NA
H. 53 kt
I. 312 deg 16 nm 01:00:30Z
J. 062 deg 77 kt
K. 312 deg 10 nm 01:02:30Z
L. 70 kt
M. 121 deg 7 nm 01:08:00Z
N. 203 deg 73 kt
O. 121 deg 7 nm 01:08:00Z
P. 7 C / 3050 m
Q. 15 C / 3052 m
R. 15 C / NA
S. 12345 / 7
T. 0.02 / 1 nm
U. AF300 1605A DORIAN OB 11
MAX FL WIND 86 KT 153 / 86 NM 23:59:30Z



Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 30th day of the month at 1:33Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF96-5300
Storm Number & Year: 05 in 2019
Storm Name: Dorian (flight in the North Atlantic basin)
Mission Number: 16
Observation Number: 11

A. Time of Center Fix: 30th day of the month at 1:05:30Z
B. Center Fix Coordinates: 23.04N 68.11W
B. Center Fix Location: 347 statute miles (558 km) to the NNW (338) from San Juan, Puerto Rico (U.S.).
C. Minimum Height at Standard Level: 2,933m (9,623ft) at 700mb
D. Minimum Sea Level Pressure: 980mb (28.94 inHg)
E. Dropsonde Surface Wind at Center: From 170 at 18kts (From the S at 21mph)
F. Eye Character: Not Available
G. Eye Shape: Not Available
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 53kts (61.0mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 16 nautical miles (18 statute miles) to the NW (312) of center fix at 1:00:30Z
J. Maximum Flight Level Wind Inbound: From 62 at 77kts (From the ENE at 88.6mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 10 nautical miles (12 statute miles) to the NW (312) of center fix at 1:02:30Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 70kts (80.6mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 7 nautical miles to the ESE (121) of center fix at 1:08:00Z
N. Maximum Flight Level Wind Outbound: From 203 at 73kts (From the SSW at 84.0mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 7 nautical miles to the ESE (121) of center fix at 1:08:00Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 7C (45F) at a pressure alt. of 3,050m (10,007ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 15C (59F) at a pressure alt. of 3,052m (10,013ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 15C (59F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 1 nautical mile



Rather than use the 91 knot reading for the inbound wind to the center, they went with 53 knots.

There was a 53 knot (61mph) reading and then every 30 seconds this:

63 mph ... suspect
70 mph ... suspect
74 mph ... suspect
74 mph ... suspect
Missing
105 mph ... suspect
97 mph ... suspect
61 mph
38 mph
36 mph ... Lowest extrapolated pressure was here and lowest wind in center

These winds were where you would expect them to be high.

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NOAA Mission (at around 750mb level, 8,400 feet):

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1st pass into center, NW to SE quadrant:

NW Quadrant:

SFMR Peak (10s Avg.) Sfc. Wind: 81 knots (93 mph)

SE Quadrant:

Flight Level Wind (30 sec. Avg.): 83 knots (96 mph)
Peak (10 sec. Avg.) Flight Level Wind: 87 knots (100 mph)
SFMR Peak (10s Avg.) Sfc. Wind: 71 knots (82 mph)

NE Quadrant (2nd pass into center, NE to SW quadrant)

Flight Level Wind (30 sec. Avg.): 92 knots (106 mph)
Peak (10 sec. Avg.) Flight Level Wind: 94 knots (108 mph)
SFMR Peak (10s Avg.) Sfc. Wind: 85 knots (98 mph) ... For two readings in a row

The 10 second estimated surface wind is the highest 10 second wind in the period of an individual ob in an HDOB, usually 30 seconds. The NHC often uses an SFMR reading that is representative as the official advisory wind speed even though it is not 1 minute sustained because the plane may not have sampled strongest winds. In this case, you have two in a row.

Measured center pressure (7:53:29pm AST): 979mb with 16 knots of surface wind. That means a pressure of likely 978mb. Maybe 977mb.

Highest momentary winds measured by one dropsonde (this might be about a half second wind on the way down, not even a gust, certainly not sustained and unless noted, not at the surface):

991mb level: 92mph ... Surface
986mb level: 109mph
981mb level: 119mph
967mb level: 120mph
960mb level: 127mph
954mb level: 124mph
925mb level: 119mph ... 1,978 feet
850mb level: 119mph ... 4,393 feet

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 95 (from the E)
- Wind Speed: 101 knots (116 mph)

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 162 gpm - 12 gpm (531 geo. feet - 39 geo. feet)
- Wind Direction: 85 (from the E)
- Wind Speed: 99 knots (114 mph)
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Thursday Evening: Dorian is strengthening based on recon - Chris in Tampa, 8/29/2019, 9:27 pm
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