Mission Summary
20191018H1 Aircraft 42RF

Aircraft Crew (42RF)
Aircraft CommanderAdam Abitol
Co-pilotRobert Mitchell
Co-pilotKevin Doremus
Flight EngineerPaul Darby
NavigatorBrian Richards
Flight DirectorMike Holmes
Flight DirectorQuinn Kalen
System EngineerMike Mascaro
Data TechnicianMac McAlister
AVAPSTodd Richards

Science crew (42RF)
LPS/RadarHeather HolbachHRD
DropsondeKathryn SellwoodHRD

Science crew (Ground)
RadarPaul ReasorHRD

Mission Plan :

NOAA 42 will fly an EMC-tasked mission into Potential Tropical Cyclone (PTC) 16 in the Atlantic Ocean. As of 5am AST (0900Z), PTC 16 is estimated to have maximum sustained winds of 35kts, minimum central pressure of 1004mb, and moving northeast (45°) at 12 kts (Fig. 1). PTC 16 continues to look better organized in satellite imagery this morning. A 03Z ASCAT-C overpass (Fig. 2) indicated that the “center” is still elongated, but may be trying to close off on the southwest end. The evolution of this system is extremely complicated given the baroclinic influences. There is a large amount of dry air over the western Gulf of Mexico associated with the upper level trough coming off of Texas impinging on the circulation (Fig. 3). There is also a warm eddy that was shed from the loop current earlier this year present in the central Gulf of Mexico that the storm is moving over and a cold eddy in the northeast Gulf of Mexico (Fig. 4). PTC 16 is entering a region of increasing shear (gradient) from 15 to 40 kts.

Figure 1: NHC forecast graphic issued at 9Z October 18, 2019.
(source: www.nhc.noaa.gov)

Figure 2: ASCAT-C overpass at 3Z on October 18, 2019.
(source: https://manati.star.nesdis.noaa.gov/datasets/ASCATCData.php)

Figure 3: GOES-16 water vapor imagery of PTC 16 at 6Z on October 18, 2019.
(source: www.tropicaltidbits.com)

Figure 4: Ocean heat content in the Gulf of Mexico on October 18, 2019
(source: CIMSS)
The planned flight track (Fig. 5) is to fly a lawnmower pattern beginning to the south of the forecasted center position. Our second leg should pass fairly close to the center and then the final two legs should get north of the center. Dropsondes will be spaced every 1.5°. We will launch 5 AXBTs targeting the warm and cold eddies where there are no Argo floats or gliders present.

Figure 5: Planned flight track.

Figure 6: Actual flight track with GOES-16 visible imagery and flight level wind barbs.

Mission Summary :

Take off Landing
Linder-Lakeland, FL 11:54 UTC Linder-Lakeland, FL 19:02 UTC
Expendables 16 sondes - all good
5 AXBT - 3 good

Prepared by the Hurricane Research Division
Oct. 17, 2019 5:55 PM EDT
Aircraft: N42RF
Proposed takeoff: 18/1200Z
# LAT LON Time
deg min deg min hr:min
1 25 0088 00 1:09
2I25 0089 30 1:29
3I25 0091 00 1:50
4 25 0092 30 2:11
5 26 0092 30 2:27
6I26 0091 00 2:47
7I26 0089 30 3:07
8 26 0088 00 3:28
9 27 0087 00 3:49
10I27 0088 30 4:09
11I27 0090 00 4:29
12 27 0091 30 4:50
13 28 0091 30 5:06
14I28 0090 00 5:25
15I28 0088 30 5:45
16 28 0087 00 6:06
We successfully flew the lawnmower pattern around PTC 16 (Fig. 6). While we were out there, NHC upgraded PTC 16 to Tropical Storm Nestor at 1736Z. The east side of the system had a lot of stratiform and convective precipitation, while the west side was dry with only low clouds. The strongest winds (flight level around 70 kts and SFMR surface winds of 45-50 kts) were on the SE side. We also found that the minimum central pressure had dropped to 1001 mb. The TDR showed very strong upper level westerlies. SSTs in the warm eddy were around 29°C and 27.6°C in the cold eddy.

In total, 17 regular dropsondes and 10 mini dropsondes were deployed. 16 of the 17 dropsondes were good and all of the mini dropsondes were good. The dropsonde at point 15 was launched near a glider that was located at 28.13°N, 88.24°W at 1308Z. 3 of the 4 AXBTs deployed were good. One of the AXBTs was stuck in the CAD and signal was lost with it, but fortunately it was still on the aircraft upon landing. The combo drops sampled the warm and cold eddies. TDR data was successfully sent to EMC. Figure 7 displays the final planview analyses from the TDR.

Figure 7: TDR reflectivity (left) and wind speed (right) planview analyses.

Mission Evaluation :

The mission was a success. We transmitted 16 dropsondes and 5 TDR analyses for ingestion into the models. Additionally, we transmitted SFMR data and had 3 good AXBT drops. We also launched 10 mini dropsondes to help with their validation.

Problems :

Some minor issues with radarsync -a and the radar workstation. Radarsync -u hung, but it was resolved with a computer reboot. The radar workstation monitor stopped working, but it was fixed during the ferry. None of these issues prevented data transmission. ASPEN also seemed to have a bug with correcting the pressure data in the tempdrop (section B) for a dropsonde that did not hit the surface.

Heather Holbach
Dec. 19, 2019

Mission Data :

Flight Director's manifest | Flight Director's log | NetCDF data
LPS log | Radar log | Drop log | SFMR data

Page last updated Jan 08, 2020
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