Irene: (14-15 October 1999)

On Thursday 14 October N43RF was tasked to do a reconnaissance mission into Hurricane Irene while it passed over Cuba with a takeoff from MacDill AFB at 1856 UTC recovering back in Tampa at 0355 UTC. Also made a conscious effort to obtain ocean thermal structure to the north and east of Irene while still fulfilling mission fix requirements.

GPS dropsonde (HSA) data format

Storm/ Date Aircraft (Duration) Altitude Experiment/ Pattern Comments (expendables)
14 October N49RF (9 h) GPS dropsondes

N43RF (9.2 h) mission summary (144 Kb)
GPS dropsondes
AXBT data
One minute listing

45 kft

5 kft

N49RF Synoptic Surveillance.

N43RF Reconnaissance/Air-Sea interaction. Fixes at 2100, 0000, and 0300 UTC. AXBT dropped ahead of storm in Florida Straits. GPS sondes in and around areas of active convection.

  • 2100 UTC fix few nm SW of Havana. 0000 UTC and 0300 UTC fixes off shore N of Havana.
  • Maximum sonde surface wind was 46 kts in W wind maxima ~20 miles NW of center (SFMR maximum surface winds ~60 kts).
  • Surface pressure 988 mb at 2100 UTC
  • TA and LF radars and SFMR worked well throughout mission.
    (11 AXBT, 48 GPS sondes)

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On Friday 15 October N43RF scheduled for Windfields at Landfall mission with take off time 1930 UTC. The landfall experiment included an initial "figure 4", a series of coastal legs along the Keys and up the E coast of FL, and traverses across the Everglades. Because tropical storm-force winds were expected at MacDill AFB, N43RF recovered in Gulfport, MS at 0311 UTC.

Storm/ Date Aircraft (Duration) Altitude Experiment/ Pattern Comments (expendables)
15 October N43RF (9.2 h) mission summary (204 Kb) GPS dropsondes One minute listing
AXBT data


8 kft

5 kft

Windfields at Landfall Experiment

N43RF Fig 4 with GPS drops at C-MAN sites and buoys in Keys to improve real-time and post-storm surface wind analyses.. Collected more wave and storm-surge data with SRA. Flight legs had radials off KAMX and KBYX. AXBTs were dropped in Gulf Stream .

AFRES recon.

  • Sondes over Everglades will help describe structure of strong tropical storm/weak hurricane as it moves across land.
  • No hurricane-force surface winds in sonde data even though some dropped in regions with >75 kt flight-level winds.
  • Rapid drop-off in winds with altitude in sondes.
  • Thermodynamic data from sondes over Everglades will help specify stability to explain why high winds did not reach surface.
  • Analysis of Doppler data may provide details of 3-D windfield to complement sonde measurements.
    (7 AXBT, 26 GPS sondes)

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©1999 NOAA/AOML Hurricane Research Division
For information about NOAA Hurricane Field Program
Updated Wednesday, 24 November 1999made with Mac