Gabrielle
20010915N
Take off :
| Ft. Lauderdale, FL
| 17:30 Z
| September 15, 2001
|
Landing :
| MacDill AFB, FL
| 01:15 Z
| September 16, 2001
|
HRD Personnel
Sim Aberson
|
Jason Dunion
|
Mission Briefing :
Synoptic surveillance mission for Tropical Storm Gabrielle, possibly
threatening the east coast of the United States.
Important points were around Gabrielle, and to get the strength
of the southwesterly winds extending from southeast of Gabrielle and
converging into the longwave trough to the northeast.
Mission Synopsis :
Flight track flown exactly as planned.
Synoptic findings :
- Because the storm was further east than forecast, the G-IV
flew within 100 km of the center (to the southeast). See
Gabrielle_panorama1.jpg and
Gabrielle_panorama2.jpg for
pictures taken from over the center of Gabrielle during the
closes point of approach. The center is difficult to find,
though a low-level swirl was seen on satellite pictures.
- Dropwindsondes 2 and 4 had 31 and 35 ktwinds at the surface.
An early call was made to the NHC specialist to relay this
information. Dropwindsonde 4 was especially interesting since
the windswere so far from the center of the storm.
- Dropwindsondes 8, 11, and 26 had superadiabatic layers near
the surface, showing the cold air above the warm sea surface in
these areas behind the cold front associated with the strong
trough that had passed off the U. S. east coast. The sondes
showed the cold front, but were unclear whether the storm was
separated from it.
- Upper-level winds were not as strong as the previous day, and
the outflow was improving, especially on the east side. This
suggests a chance of intensification for the next day. The
upper-level winds well to the north were hostile to any
development.
- A confluence zone was evident to the northeast of the center
at mid-levels. Winds to the east were southerly, and they met
easterly winds further north, somewhat reminiscent of a
warm-front scenario at the surface. This was in the regions of
the frontal zones.
- A 700 hPa ridge was evident extending from the U.S. out to
about 32.5°N 77°W, building in from the west. This
should not be strong enough to turn the storm back to the west,
and does not extend much higher than 700 hPa.
- A circulation at 850 hPa was seen at 32.5°N 73°W.
This may have been a frontal low.
Evaluation :
- Jason Dunion was fully trained to run HAPS and process
dropwindsondes. He was able to process the last sondes, make
plots, archive the data, and shut down HAPS on his own.
- The data showed a stronger asymmetry across Gabrielle than
expected, suggesting more rapid movement to the northeast. The
impact on the models is currently
unknown.
- Click here to see
the impact of the dropsonde data on the forecasts.
Problems :
- There was only minor SATCOM difficulty, especially around
sunset.
- Only one dropwindsonde (17) was replace, due to fast fall.
DROP LOCATIONS
Aircraft: N49RF
Takeoff: Sept. 15 at 17:30Z
#
| LAT (° m)
| LON (° m)
| ELAPSED TIME (h:mm)
|
1 | 28 | 23 | 78 | 30 | 0:22
|
2 | 29 | 23 | 76 | 30 | 0:40
|
3 | 31 | 23 | 75 | 30 | 0:58
|
4 | 33 | 30 | 75 | 30 | 1:15
|
5 | 35 | 30 | 74 | 15 | 1:34
|
6 | 37 | 30 | 73 | 00 | 1:53
|
7 | 37 | 30 | 70 | 30 | 2:11
|
8 | 37 | 30 | 68 | 00 | 2:29
|
9 | 35 | 30 | 68 | 00 | 2:45
|
10 | 35 | 30 | 70 | 00 | 3:00
|
11 | 35 | 30 | 72 | 00 | 3:15
|
12 | 33 | 30 | 73 | 00 | 3:33
|
13 | 33 | 30 | 70 | 00 | 3:55
|
14 | 31 | 30 | 70 | 00 | 4:12
|
15 | 31 | 30 | 71 | 05 | 4:25
|
16 | 31 | 30 | 73 | 30 | 4:38
|
17 | 29 | 30 | 73 | 30 | 4:54
|
18 | 28 | 15 | 74 | 45 | 5:08
|
19 | 27 | 00 | 76 | 00 | 5:22
|
20 | 25 | 49 | 77 | 19 | 5:37
|
21 | 24 | 40 | 78 | 40 | 5:51
|
22 | 23 | 30 | 80 | 00 | 6:05
|
23 | 23 | 30 | 82 | 30 | 6:24
|
24 | 23 | 30 | 85 | 00 | 6:44
|
25 | 25 | 45 | 84 | 00 | 7:04
|
26 | 28 | 00 | 85 | 00 | 7:24
|
Return to Gabrielle mission page.
Return to Gabrielle page.