Bobgram

Bob McDavitt's ideas for sailing around the South Pacific. Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world. Compiled 02 August 2026 A review of last month's weather Here is a link to a YouTube clip giving an animated loop of the isobars and streamlines For last month is at youtu.be/rB2Adl_wxt0 Most of the month brought winter anticyclones to New Zealand, but a cold pool produced a deep fast-moving low on the 7th. Notice the lows forming near the equator and in mid -Pacific.. This is consistent with the rapidly intensifying El Nino. In an El Nino the Walker Circulation over the Pacific equator shifts so that its rising pillar gets close to 180deg/ Kiribati. The 500hPa heights and anomalies shows that prolonged upper low over Tasman sea late in the month can be seen at http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.shtml Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml El Nino 's warmth in the eastern equatorial pacific is intensifying , and that cooler patch on its southwest side over Southwest pacific is bringing intensifying dry conditions . The march towards El Nino in the Equatorial Eastern pacific may be seen in a Time /Long plot for 7 degrees around the equator The equatorial current has turned into an east-going river up to 3kt in places. Average isobars for past month (below) The Indian Monsoon stuttered a bit last month and accumulated a 15% deficit in rainfall in the season-to-date. The subtropical ridge has weakened a lot between Tahiti and Chile. Pressure anomalies for past two months (below) The anomaly pressure pattern for last month shows a low breeding area northeast of New Zealand extending to Easter Island. This is an indicator that French Polynesia may have periods of unsettled weather over the next few months Previous month below Last month above The 1020 isobar is in much the same place as last month over Australia but has retreated westwards over New Zealand, and disappeared further east. TROPICS . Typhoon Noul: After leaving three people dead in the far northern Philippines, Typhoon Noul lashed Hong Kong and China's Guangdong province with sustained winds of up to 101 mph, downing trees and utility lines. . Hurricanes Fausto and Genevieve passed westward across the eastern Pacific without directly affecting any land areas. . Super Typhoon Dolphin intensified to Category 5 force over the open waters of the central Pacific, north of the Marshall Islands. WEATHER ZONES Low L1 near Kermadecs tonight is expected to travel southeast and associated front/convergence zone should cross Niue /southern Cooks /Society Islansd s next few days--- not much in the way of showers but a wind change to NE then S/SE and an increase in southerly swells. Low L2 is expected to travel to NE east of NZ next few days, shovelling southerly chilled air northwards. This makes High H1 which follows it mid-week across New Zealand FROSTY. Next week, when H1 gets east of NZ, I expect it to intensify and enhance the trade winds between Tahiti and Tonga. Low L3 is expected to move north-eastwards across Tasmania on Monday and eastwards across the Tasman this week then southeast over southern NZ late in the week, followed by High H2. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> If you would like more details about your voyage, check metbob.com Or Facebook at /www.facebook.com/metbobnz/ Weathergram with graphics is at metbob.wordpress.com (subscribe/unsubscribe at bottom). Weathergram archive (with translator) is at weathergram.blogspot.co.nz. Contact is bob@metbob.com or text 64277762212. >>>>>>>>>>>>>>>>