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 21 June2026 Overnight tonight we are having our winter solstice. So daylength tomorrow is 1 second longer than today. The saying goes that when the days get longer the cold gets stronger. And yes, the coldest time of the year in New Zealand is usually in early August around 6 weeks (or half a season) after the solstice. The Guardian has reported that Antarctic temperatures this winter have risen 10C above average in a record heatwave. The new winter peak temperature was logged by the Argentinian Esperanza base on the Trinity peninsula on 6 June amid a protracted heatwave, when the maximum daily temperature exceeded zero degrees for three consecutive weeks. Scientists said the high of 15.4C broke the previous record set at the same station in 1998 by 2C. It is also about 20C above normal for this time of the year. That is a huge anomaly. Unusually strong warm winds from the north blew across much of the Antarctic peninsula. On King George Island, 100 miles (160km) from Esperanza, researchers said the landscape had changed from mostly white to brown, grey and green after temperatures hit 4.6C on 6 June. “Last weekend was very strange. The temperatures here went very high so everything outside melted,” said Luis Muñoz, a Chilean glaciologist. “Usually there is 20cm of snow and a lot of ice on the ground at this time.” It will be interesting what happens when this El Nino reaches its peak in a few months’ time. Another problem that has arisen this month is the eruption of an undersea volcano on the Titan Ridge in the Bismark Sea. Pumices is coating a large area and floating around surrounding islands. This is likely to affect anyone planning to sail that way later this year. TROPICS TC MEKKHALA is heading towards southern Japan WEATHER ZONES Weather Zones Mid-week GFS model showing isobars, winds, waves (purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge), SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone) SPCZ is expected to have a normal week and still be situated north of its normal position. There is a trough tonight between Niue and Tahiti part of the SPCZ. A cold pool has formed aloft on its western side, and this is expected to drop to the surface and form a LOW south of Rarotonga. The Low Lq1 should then deepen and move off to the SE and then to the east. Its associate trough is expected to bring NE wind and rain to Tahi around local Tuesday and then a few days of SW swells. HIGH H1 stretches this evening from Brisbane to Raoul, but this part is expected to shrink next few days and another HIGH crossing the South Island on Monday is expected to enlarge over Chathams on Tuesday then travel east on to the south side of L1. LOW L2 is now forming east of Sydney and is expected to deepen but then develop multiple centres as it crosses northern New Zealand on Wednesday and Thursday finally weakening over Chathams at the weekend. It is expected to be followed by a burst of SW swells over 3.3m that may reach as far north as Fiji to Tonga by Saturday. HIGH H2 is expected to travel east across the Aussie Bight reaching Tasmania by end of the week. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>>

Bobgram 14 June 2026

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 14 June2026 Comparison of two recent coastal inundation events at Wellington South Coast Tuesday 9 June brought huge swells that inundated Wellington's south coast This had a Isobar reading 1008 Compare that with the 15-16 Feb 2026 coastal inundation weather pattern On that date the isobar reading was around 998. One of the factors we consider during coastal inundations is the "IB" or inverse baric /inverted Barometer effect. Average atmospheric pressure at sea level on this planet is 1013.35hPa, hence 1012hPa is always the straightest isobar on the weather map and divided High pressure weather from Low pressure weather. Every hPa above that depresses sea level by 1cm Every hPa below that raises sea level by 1cm There is a tidal gauge at Queens wharf in Wellington Harbour. It wasn't exposed to the large swell waves on the South Coast but was measuring the IB on 9 June 2026 The SS trace measures storm surge. More information about coastal inundation is available from one of the blogs I wrote for MetService back in 2011 : blog.metservice.com/Storm-Surge-23-Jan-2011 TROPICS There are no named storms this evening. .Mexico's Guerrero state was soaked by short-lived Tropical Storm Boris. . Tropical Storm Christina brought locally heavy rain and strong winds to parts of Nicaragua, Honduras and El Salvador. WEATHER ZONES SPCZ is expected to have a weak week and be situated well north of its normal position. HIGH H1 travelled east across NZ last week and should continue its migration along 30 to 35S this week. The burst of southerly swells on its eastern side is finally fading over Tahiti tomorrow. An upper trough moved across New Caledonia last few days and now its activity is descending between Vanuatu and Fiji, fading away the trade winds. On Monday it is expected to develop a surface low L1. This Low is then expected to deepen as it travels to the southeast, crossing Minerva on Wednesday. Fronts associated L1 and expected to travel east from Tonga to Tahiti this week . It planning to sail west , it may be a good idea to stay-put until this trough clears Tahiti around local sat 20 June. High H2 that is moving into the Tasman Sea next few days is expected to be diverted to the NE by L1. This opens the southern door. So even though the next Low L2 may start this week near 35S over South Australia, it is expected to brew a series of fronts that may cross the South Tasman Sea and South Island. This is activating the roaring 40s , and is in tune with an El Nino pattern that has now been declared www.noaa.gov/news-release/el-nino-forms-expected-to-strengthen-say-noaa-fore casters >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>>

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 07 June2026 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/1pKfA8c4s2U May was a LOW INDEX month, with blocking Highs traveling slowly east along around 45S and a series of lows crossing Australia and then traveling east across the Pacific at around 25s. For more information about "Low index weather pattern nz" The index being referred to is the Zonal index, usually Z1, and that is simply the barometric pressure difference (Auckland-Christchurch). When this is high, NZ has westerly winds. Well last month is was low and sometimes negative. Another impact of Low index has been the rainfalls . Parts of eastern Australia have had their wettest May of record. And parts of NZ have a record-breaking DRY month. The thing about the Low index pattern is that it usually flips into a high index pattern after a few weeks. I think this low index pattern is acting as a herald for a switch to a high index pattern. And El Nino encourages a high index. The 500hPa heights and anomalies shows that prolonged upper low over Tasman sea late in the month as 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 The waters over eastern equatorial Pacific are warming --- El Nino is kicking in. There is a well-established warm zone between Hawaii and LA. Since most of the North pacific is now on the warm side, the projections towards a super El Nino seem to be on target. The cool zone around NW of Australia has almost gone. Average isobars for past month From www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html The subtropical ridge in the southern hemisphere has further intensified and expanded both to north and south. The Monsoon has arrive over southern India around normal. Pressure anomalies for past two months The anomaly pressure pattern for last month now shows a low breeding area between Hawaii and Galapagos. . The southern subtropical ridge intensification is well developed over NZ, and there is still a low breeding area over New Caledonia = Low index. The 1015 isobar has stayed north over Australia near Cairns and there is a 1025 over central New Zealand. TROPICS AMANDA has been named in the northeast pacific. Tropical Storm Jangmi swept across much of Japan, bringing torrential rain, flooding and strong winds from Okinawa to the Tokyo region. At least 23 people were injured and dozens of homes were damaged by the storm. WEATHER ZONES SPCZ is of average intensity but somewhat north of its normal position. GFS model has a low forming near Fiji next week and that would create a squash zone near 20S . Other models disagree but, because of the intensity of a High crossing NZ also have a squash zone stretching across New Caledonia /Fiji to between Samoa and Tonga. Main feature this week is the upper cold pool east of NZ. It is expected to form a series of surface lows and these are expected to produce a burst of long-period southerly swell peaking at 10m near 35S 175W and spreading 4m swells as far west as 175E by Wednesday and as far east as southern Tahiti by local Thursday. This is the sort of swell that Tahitian surfers dream about. Then we have the 1036hPa HIGH slowly crossing Tasman Sea and New Zealand this week. Usually a good pattern for sailing north but complicated this week by those large southerly swells mid-week and a possible squash zone near Fiji early next week. Since the models ideas about the Fiji squash zone early next week may change next few days one idea is to head from NZ to NNW at first, avoiding the larger swells. then neat 25S get an update and if Fiji is getting too yucky then turn left and go to Noumea (Plan B) Lows L1 and L2 in the southern ocean are expected to travel east along 50S , to south of H1. Wind accumulation for next week from windy.com above shows the path of wind accompanying the L1 and the building of squash zone between New Caledonia and eats of Fiji >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>>