1. bore mission of 4 June

2. First event Homestead observations only leading wave @ Homestead at 6:45 Z

3. First event

4. Note limited surface cooling, for the first bore event. Dynamic cooling is superimposed on radiative cooling, sunset is at 2:00 Z, sunrise at 11:30 Z The real dynamic cooling occurs 2 hours after the second bore event. “first” bore “second” bore 7 Z AERI sounding Radiative cooling another bore??

5. First event Three amplitude-ordered waves, the first one the tallest - this suggests a mature bore system. However there is one low-amplitude wave ahead, also seen by MAPR FM-CW 6-8 Z

6. ISS1 location: at Homestead First a 2 mb pressure jump associated with bore, then some waves Cold front?? 1st event 2nd event this suggests some vertical mixing

7. 7:02 Z

8. Amplitude-ordered wave train - but first wave seems smallest?? Anyway, this image is consistent with FM CW

9. second event leading wave @ Homestead at 10:50 Z UWKA/WCR data “second” bore cold front

10. Cold-frontal passage near 12:30 Z ??

11. This may or may not be the same event. ~90 km in 3h45m implies a speed of 6.7 m/s DDC wsr-88d 17:04Z

13. 12:0011:00 FM-CW 10-13 Z 10:50: first UWKA leg over Homestead 1000 1500 m AGL Is this real?? Cold-frontal passage around 12:50 Z

14. 10:50: first UWKA leg over Homestead 10:50: strong, gusty winds were reported by a person on the ground at Homestead

15. 10 Z 12 Z 11 Z 13 Z considerable cooling 700- 910 mb parent density current?? inversion suggests calm conditions AERI soundings

16. WCR nadir antenna reflectivity Time (UTC) Flight level: 1850 m AGL Height below flight level (m) June 4 2002 dBZ Homestead FLIGHT LEVEL DATA ON THE NEXT PAGE Some wave activity ?? the ground WCR echo strength is very weak at night, compared to the daytime CBL … Aspect ratio: 1:4

17. temperature potential temperature vertical air velocitystatic pressure (u,v) theta-e mixing ratio BORE: The sustained nature of the change, ahead of a much more shallow gravity current, suggests that this is a bore. This flt level (1850 m AGL) seems to penetrate the bore: the flt level temp behind the bore is some 3 K less. This suggests that the waves are deeper than what FM-CW suggests Consistent with AERI, the air is more humid behind the bore, with some 4 g/kg more water vapor. However the cooling may NOT be consistent with AERI. The net effect is a higher  e behind the bore, about 5 K higher. WAVETRAIN: The covariance of  and T imply that the aircraft didn’t bob up & down in a stratified, undisturbed environment, but rather that the aircraft was rather level in a wavetrain The waves are ranked in amplitude, the first one the highest amplitude, and they may be ranked in wavelength, the first one the shortest; this is consistent with FM-CW & MAPR The vertical drafts have a magnitude of ~2 m/s or less. Assume that this is simultaneous transect. The coldest air has seen a history of ascent, so the wave must move forwards. The pressure variations at this level are mainly a response of the aircraft to the vertical motion field in which it is embedded, flying from right to left. A 1 m/s updraft during 20 sec is 20 m ascent or 2 mb hydrostatic pressure decrease. SE NW c w Wave propagation Homestead

18. SENW Homestead Where is the trailing wavetrain? It may be further to the SE - unfortunately this is the end of this flight leg Flight level ~250 m Wave crest ahead of cold front??

19. SENW Flight level ~160 m Cold front wave trofs on the cold- frontal surface? Prefrontal updraft/cooling Homestead Cold front frontal motion Cold front reaches Homestead ~12:50, ie 60 min later over 30 km, ie the frontal speed is ~ 8 m/s

20. Cold front wave trofs on the cold- frontal surface? Prefrontal updraft/cooling VHF radio interference WCR nadir antenna reflectivity Time (UTC) Flight level: 160 m AGL dBZ Aspect ratio: 1:4 WC zenith antenna reflectivity Height above flight level (m) SENW WCR up-looking

22. WCR nadir antenna reflectivity Time (UTC) Flight level: 750 m AGL June 4 2002 dBZ Height below flight level (m) Homestead The wave crests were associated with shallow lenticular clouds, and cloud droplets may explain some of the echo. It is not clear what the continuous fine line is. SENW Aspect ratio: 1:4 cold front below (<750 m deep)

24. Conclusion for the 11:57-12:10 leg: I suspect that this is a gravity wavetrain above the cold frontal surface. The highest amplitude wave appears to be just ahead of the sfc cold front, separated by some 15 km. Perhaps this is the beginning of a new bore? SENW wave propagationanother low- amplitude wave ? Homestead Flight level: 750 m