010913I P3 mission 5, 13 Sept 2001 D. J. Raymond As in mission 4, except dropping ocean probes. 1430 - C130 launch. 1436 - P3 launch. The weather in Huatulco is clear and calm. 1440 - Hazy offshore. 1443 - Level at 6000 ft. 1446 - Distant deep convection E and SE. Clear below. Occasional whitecaps. 1448 - Small cu and then towering cu SE (ahead) backed by anvil cloud. Radar verified on. 1450 - NE-SW line of cells 100 km SE. Wind NE 5 m/s. 1455 - The above line consists of towering cu, tops estimated at 5 km. Dark stratus region behind. 1458 - Stratus tops to 12 km. FSSP working. 1459 - Thru towring cu. Very hazy here. Over small cu sheared from N, variety of cu in distance topped by stratiform. 150315 - Into towering cu. 150640 - Thru more active cu. Bases of stratiform about 5 km, tops 12 km. 1509 - Clear below, a few whitecaps. Wind waves appear to be from N. 1510 - Passing NE side of cell. Light rain. 1513 - Moderate rain. 54% humidity! 48%! 1516 - Clear below, light rain, approaching edge of stratiform area. Still hazy. Must be blowing off land. 1529 - Still clear below, trade cu ahead. 1533 - C130 reports hazy conditions, high CN counts, wind from NW, so we are indeed getting stuff off of land. 1535 - Depressurizing for drops. No whitecaps. C130 reports cloud base about 500 m. 1538 - Clear below, suppressed cu E. No whitecaps. Clear above. 1542 - Clear above and below. 1548 - Clear below, small cu ahead, cirrus distant S. No whitecaps. 1551 - 93 W, 12 N, few small cu, turn S. No whitecaps. 1558 - Towering cu/small Cb distant SE, suppressed cu below, clear above, no whitecaps. Still haze. 1610 - Deep conv. towers SE and SW, just a few small cu below, clear above, drops show very light winds at surface. Scattered echos S of 100 km S of us. Haze now concentrated into a layer somewhat below us. 1620 - Approaching EW line of towering trad cu, Cb far to SE. No whitecaps. 1626 - Winds 4 m/s ENE surface. Heading thru towering cu region, tops estimated at 4 km. Light rain. Haze is much decreased. 9.75 N. Region of general towering cu, No whitecaps. This is clearly an area of developing convection. Tops 4-5 km. 1633 - About to penetrate substantial cu mass. Tops 4-5 km. 1640 - Still in region of towering cu. Some tops to 6 km. Getting good reflectivities on pilot radar. Some tops to 9 km. 164418 - Heavy rain. Avoided highest reflectivity. Tops getting higher as we go south. Sonde -- surface wind SW 5 m/s. 1649 - Whitecaps, broken trade cu to 2-3 km. 1650 - Layer clouds just below us, showers with tops to about 5 km scattered to S. Small clouds sheared from NE. Lots of clouds in this region below our flight level. 1654 - 93 W, 8 N, turn W. Still a weak haze layer above our level. Surface winds 8 m/s SW. 1659 - Lots of trade cu, layer clouds below us, whitecaps. 1706 - In region of trade cu with occasional tops to 4 km or higher, much more convection to N. Whitecaps. 1713 - Small trade cu between occasional shower systems with tops 4-5 km. 1714 - 94.3 W, 8 N, turn N. 1722 - Trade cu here, substantial shower mass ahead. Some whitecaps. 1728 - Passing thru lines of showers, tops 7-9 km. 1735 - Region of scattered showers with tops to 8 km or more. No whitecaps. 1742 - Getting out of region of showers. Mostly just small trade cu ahead. No whitecaps. Somewhat hazy. 1744 - This may be a day in which vertical development is limited by dry air aloft. 1749 - Cb to E with top to 15 km. Small cu here, with occasional towering cu. No whitecaps. 1807 - C130 starting sounding. Suppressed cu in this locale. Very light winds at surface. In the light wind regions there seems to be an inversion at about 1000 m, which doesn't exist in the strong wind areas. 1815 - No clouds above or below us. Distant towering cu NE thru NW. 1819 - 94.3 W, 12 N, turning W. Some low layer clouds N, clear S. I have the impression that the ITCZ convection is developing westward, which nearly matches our westward march. What luck! 1838 - Light NW winds at surface, clear to S, layer of clouds, trade cu, cirrus to N. 1839 - 95.7 W, 12 N, turn S. 1841 - Towering cu visible ahead. 1848 - Just a few very suppressed cu below us, clear above. Some layer cloud well below us. Very hazy. 1853 - EW line of convection 60 km ahead of us. 1855 - C130 about same lat as we are. 1859 - C130 will penetrate westernmost cell on line. Sounding shows that air is very dry above 3 km. 1903 - Penetrating line, tops to 5-6 km. Multiple cloud bases S of line -- one at about our level. No whitecaps. 1907 - Scattered trad cu sheared from NE. Deep Cb 60 km SSW. 1915 - 10 N -- winds very light SE at surface. Trade cu. 1917 - C130 penetrating deep cloud. Tops about 10 km. Most trade cu around us reaching only our level. Some Cbs distant SW. 1926 - 9.07 N no whitecaps, trade cu sheared from NW around us, deep towering cu visible SW, 150-200 km. Large mass of not-too-deep cloud SSW 40 km. 1932 - 9 N, SW winds 3 m/s at surface. Tops of trade shower E of us estimated 3-4 km. 1941 - Solid masses of trade cu with tops to about 3 km, surrounded by suppressed cu fields. Starting to get layered clouds. 1944 - 95.7 W, 8 N, turn west. Towering cu ahead. 1948 - Going thru some trad cu tops. surface winds 8 m/s SW. Major Cbs ahead. 2001 - Starting penetration along S end of Cb line, which stretches NE-SW. Tops to 16 km. 2005 - 97 W, 8 N, turn N in Cb, which gave us rain, but not much turbulence. 200709 - Thru layer cloud -- prob. detrainment layer. 2008 - Lot of layer cloud below, clear above. Surface wind 2 m/s SW. No whitecaps. 2014 - Some cells on radar 250 km NNW. 2020 - Small trade cu below. Cbs distant NW. Deep towering cu NNW. 2027 - Patch of deeper trade cu. 2034 - Clear below, no whitecaps. 2037 - C130 will penetrate deep Cb at 4 km. 2045 - Few small cu nearby -- otherwise clear. Region of extensive cu, some deep, ahead (N) and to W. 205040 - Penetrating growing cu. 205433 - In region of building cu. 2056 - Out of region of building towers, just small cu. 11 N, very weak surface winds. 2100 - Layered cloud just below us, cu tops reaching our level. Cbs distant NE and NNE -- 200 km on radar. 2107 - Lots of layer cloud and haze. Why are Cbs building in this area? Is it the higher humidity? Surface fluxes are certainly weak here. 2112 - 97 W, 12 N, head for Huatulco. No whitecaps, surface winds NW 3 m/s. 2120 - Growing convection and Cbs all quads. Layer clouds at our level. 2124 - Trade cu tops to 4 km. Cb tops to 10-11 km. 212929 - Penetrating convection -- vertical velocity up to 6 m/s. 2131 - No whitecaps. Small cu. Very murky. 2138 - Just a few small clouds below -- deep cell to E, murky. 2142 - Clear below, no whitecaps. 2203 - Clear below, approaching coast. 2220 - P3 recovers. C130 is already here. Problem with FSSP data collection toward end of flight.