MISSION PLAN

FLIGHT ID

20210906I1

STORM

AL12 / LARRY

MISSION ID

WB12A

TAIL NUMBER

NOAA43

TASKING

HRD

PLANNED PATTERN

Butterfly

MISSION SUMMARY

TAKEOFF [UTC]

1447

LANDING [UTC]

2330

TAKEOFF LOCATION

St. Croix

LANDING LOCATION

St. Croix

FLIGHT TIME

8.7

BLOCK TIME

8.9

TOTAL REAL-TIME RADAR ANALYSES

(Transmitted)

3 (3)

TOTAL DROPSONDES (Good/Transmitted)

21 (20/20)

OCEAN EXPENDABLES (Type)

 8 ONR AXBT, 2 AOML/PhOD ALAMO

sUAS (Type)

None

APHEX EXPERIMENTS / MODULES

Mature Stage Experiment: Eye-eyewall Mixing; Ocean Observing: Sustained and Targeted Ocean Observations

HRD CREW MANIFEST

LPS ONBOARD

Holbach

LPS GROUND

Wadler

TDR ONBOARD

Holbach

TDR GROUND

Gamache

ASPEN ONBOARD

Hazelton

ASPEN GROUND

None

NESDIS SCIENTISTS

Chang, Jelenak, Sapp

GUESTS (Affiliation)

None

AOC CREW MANIFEST

PILOTS

 Didier, Copare, Stateler

NAVIGATOR

Hough, Richards

FLIGHT ENGINEERS

Darby, Bennet

FLIGHT DIRECTOR

Holmes

DATA TECHNICIAN

Mascaro

AVAPS

Warnecke

PRE-FLIGHT

Flight Plan

Plan is to target the Eye-eyewall Mixing Module for either the second or third pass, if time allows. Plan would be to fly upwind around the eye to get more radar scans since we would be flying a little slower

Expendable Distribution

Flight plan described in previous section. In addition, fixes each pass and NHC also requested RMW sondes in the NE and NW.

Preflight Weather Briefing

From NHC discussion: “Larry currently has an annular structure, with a 60 n-mi diameter eye and a relatively thick eyewall.  High-resolution visible imagery shows several meso-vortices rotating within the eye, which is

typically observed in strong hurricanes.  The upper-level outflow

has become better defined over the western portion of the

circulation, indicative of decreased shear in comparison to

yesterday. The advisory intensity is kept at 105 kt, in reasonable

agreement with the latest Dvorak estimates from TAFB and SAB.”

Current satellite imagery:

Instrument Notes

[Notes about instrument status prior to the mission]

IN-FLIGHT

Time [UTC]

Event

1448

Takeoff from St. Croix

1513

En route to Larry…

1618

Data comms issues. Everyone on N43 logged off of x-chat. Also, no flight-level wind data showing up in MTS

1630

Comms is back. Heather reported that they can see some pretty decent swells propagating towards us (outward from Larry)

1644

Crew reported that they can see the curvature in the outer banding as we're approaching the outer edge of Larry

1654

Started descent

1659

Quite a few visuals of whitecaps before starting the pattern. SFMR reports ~24 m/s

1703

Starting pattern at 10 kft. Combo drop 1 out. SST is 27.5°C which was questioned by the flight crew. It is possible since the storm is near a SST gradient

1709

Heading towards the eye

1718

Sonde 2, Midpoint inbound pass 1 (2nd sonde)

1722

Penetration through the eyewall reported different. Not as defined as usual

1725

Hunting the center in the eye (marked at 1326)

 Gamache gave center fix for radar analyses: 172607, 22.06N, 53.45W

1726

Center sonde, pressure of 957.5 mb (3rd sonde)

1731

Echo tops are only showing to ~ 5-6 km on the edge of the scans (as going into northern eyewall)

1738

Heather reported much broader area of moderate precip on the N side

1744

Midpoint outbound sonde. Leg 1 (4th sonde)

1754

EP combo drop out (5th sonde), 28.31°C SST. Interesting comparison to SHIPS which has 28.8°C, though there might be a gradient with higher SSTs ahead of storm motion

1821

1st ALAMO float released

1831

2nd ALAMO float released

Radar analyses from 1st pass

1853

Combo sonde, inbound pass 2 (sonde 6)

1905

MP sonde inbound pass 2 (sonde 7)

1912

RMW sonde inbound pass 2 (sonde 8, NW eyewall)

Once we were inside the reflectivity eye, we hit our worst turbulence of the flight. They wonder if that was one of our mesovortices

1918

Center sonde (sonde 9)

1933

Midpoint sonde outbound pass 2 (sonde 10)

1940

Close overlap between P-3 and G-IV

Snapshot from tidbits to highlight the “bounce” the aircraft took during the pass (bottom right plot)

1945

EP combo sonde pass 2 (sonde 11) (26.92°C SST)

Last hour of vertical velocities. Very turbulent on the outbound of the previous pass

1959

Midpoint sonde on downwind leg (sonde 12)

2011

Initial point (IP) combo drop pass 3 (27.96°SST) - sonde died (sonde 13)

2015

Backup IP sonde (sonde 14)

2023

Midpoint sonde Inbound leg 3 (sonde 15)

2028

RMW sonde inbound leg 3, NW eyewall (sonde 16)

2036

Center sonde (sonde 17)

2039

Begin Eye-eyewall Mixing Module. Circling eye clockwise

2053

Image captured orbiting the eye

2107

Sonde (#18)  in mesovortex for Eye-eyewall Mixing Module. Visible imagery is fading, so hard to see where it was

2116

RMW sonde outbound pass 3 (SW eyewall) (sonde 19)

2122

Midpoint sonde outbound pass 3 (sonde 20)

2136

Endpoint combo sonde (sonde 21)

Updated satellite loops at the end of mission

KAIA Significant Wave Height from mission

POST-FLIGHT

Mission Summary

This was a highly successful mission. A butterfly pattern was flown with two ALAMO floats released ahead of the motion after the 1st pass through the center. On the third pass, an Eye-Eyewall Mixing Module was flown which consisted of a clockwise circumnavigation of the eye and a dropsonde in a potential mesovortex. In addition to the standard pattern, three RMW sondes were launched and a center fix was made for each pass for NHC.

The radar data was used for the 5 PM ET NHC forecast discussion to discuss surface winds, which we believe is a first. “During that pass through the hurricane, the aircraft tail Doppler radar measured winds of 121 kt at a height of 3 km in the northeastern eyewall, which equate to

about 109 kt at the surface. Therefore, the initial intensity has

been adjusted up to 110 kt for this advisory. A pair of dropsondes

into the eye of Larry measured a minimum central pressure of 956 mb.”

21 total dropsondes were released (14 for EMC, 2 for NHC, 4 for HRD, 1 for ONR), as well as 2 AOML/PhOD ALAMO floats (both failed) and 8 NRL AXBTs (1 bad)

Actual Standard Pattern Flown

Butterfly + Eye-eyewall Mixing Module

APHEX Experiments / Modules Flown

Released 2 AOML PhOD ALAMO floats ahead of storm motion, part of the Ocean Observing Experiment: Targeted and Sustained Ocean Observations and flew an Eye-eyewall Mixing Module, part of the Mature Stage Experiment; mission flown in collaboration with ONR TCRI.

Plain Language Summary

• A highly successful research mission which collected radar data, temperature, humidity and wind speed data from dropsondes.  
• We worked collaboratively with the National Hurricane Center to meet both of our goals
• We released two ocean sensors ahead of the storm to understand how the ocean evolves underneath the storm
• We flew a circle inside the eye to understand how the eye and violent eyewall interact with each other

Instrument Notes

An issue with the MMR on N43. The Flight Director said that the one on N43 is worse than on N42. Surface roughness field is ok, but HWX and NAW are bad -- lower than expected reflectivity on the MMR.

Final Mission Track