Random Chaos
(Weather Analyst)
Thu Aug 25 2011 10:43 PM
Re: Gloria

Yep. Dropsonde measured 942mb surface pressure where HDOB was showing 942mb also, just south of the really low 937mb. My guess is the storm isn't perfectly vertically stacked, and the FL center is 5 miles south of the surface center. The eye is larger than that difference.

Winds are still barely Category 3, yet pressure is easily strong enough for a mid Category 4. So the wind field must be expanding rather than increasing in velocity, as Mike said.

Official vortex recon, using the dropsonde surface pressure:

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 26th day of the month at 02:16Z
Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)
Storm Number: 09
Storm Name: Irene (flight in the North Atlantic basin)
Mission Number: 23
Storm Number & Year: 09L in 2011
Observation Number: 36
A. Time of Center Fix: 26th day of the month at 1:58Z
B. Center Fix Coordinates: 27°49'N 77°21'W (27.8167N 77.35W)
B. Center Fix Location: 184 miles (295 km) to the ENE (65°) from West Palm Beach, FL, USA.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 82kts (~ 94.4mph)
E. Location of the Estimated Maximum Surface Wind: 13 nautical miles (15 statute miles) to the NNE (31°) of center fix
F. Maximum Flight Level Wind Inbound: From 128° at 99kts (From the SE at ~ 113.9mph)
G. Location of Maximum Flight Level Wind Inbound: 18 nautical miles (21 statute miles) to the NE (35°) of center fix
H. Minimum Sea Level Pressure: 942mb (27.82 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17°C (63°F) at a pressure alt. of 2,445m (8,022ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 2,440m (8,005ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 16°C (61°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the southwest
M. Eye Shape & Diameter: Circular with a diameter of 25 nautical miles (29 statute miles)

N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: Other - Not surface, 1500ft, 925mb (if vortex is newer than about mid 90's; see note for more), 850mb, 700mb, 500mb, 400mb, 300mb or 200mb
O. Navigation Fix Accuracy: 1 nautical mile
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 111kts (~ 127.7mph) in the northeast quadrant at 21:25Z

Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center