If you thought December was wintry...

[tich]

Read this:

SUMMER INTO WINTER

Heavy snow fell to low levels in inland parts of Otago, Southland, and South Canterbury on the 5th and 6th, with light falls reaching near sea-level. Heavy snow also fell throughout the central North Island on the 6th, closing many roads. Taupo had its lowest maximum on record, with snow on nearby hills, and heavy falls stranding motorists on the Napier-Taupo Highway at Rangataiki.

Very cold southwesterlies brought snow to low levels in Otago and Southland from the 9th-13th, closing roads and schools, including those on Dunedin's hill suburbs. Falls also affected the central North Island, reaching low levels (including Taihape and hills around Taumaranui) overnight on 11th.

A bitterly cold southerly outbreak spread over NZ from the 17th-19th, starting in the south of the South Island on the afternoon of the 17th. Snow fell to sea-level in the south and east of the South Island, with heavy falls disrupting the hill suburbs of Dunedin and Christchurch. In the North Island, snow fell to unusually low levels in many areas, including inland Taranaki (flurries even reported on the outskirts of New Plymouth). Snowflakes were reported in some Wellington hill suburbs and the Rimutaka Hill Road was closed by snow. Many other roads were also closed, including the Desert Road, Napier-Taupo Highway, and high country roads inland from Gisborne. Snow dusted many hills in the Waikato and around Rotorua. Light falls were even reported on the Hunua ranges, southeast of Auckland, plus sleet in the Waitakares. Auckland itself was lashed by frequent hail showers and strong cold southwesterlies.

A complex trough moved onto NZ from the 21st-23rd. Heavy snow showers again closed many roads in the central North Island, while snow also fell to low levels in the Southern Lakes area. Lighter snow showers continued on the high country of both islands through the 25th.

This is what I guess would've happened if the weather pattern we had experienced last month, had occurred in a winter month. December 2004 was 2.2C below normal nationally, though I wonder if a winter month with exactly the same weather pattern would also be 2.2 below normal, as cold southerlies are more frequent in winter anyway.

[RWood]

Read this:

SUMMER INTO WINTER

This is what I guess would've happened if the weather pattern we had experienced last month, had occurred in a winter month. December 2004 was 2.2C below normal nationally, though I wonder if a winter month with exactly the same weather pattern would also be 2.2 below normal, as cold southerlies are more frequent in winter anyway.

At the NIWA site from this link you'll find a MSLP anomaly map for December - it's quite impressive.

http://www.niwa.co.nz/ncc/cu/2005-01

[RWood]

Read this:

SUMMER INTO WINTER

This is what I guess would've happened if the weather pattern we had experienced last month, had occurred in a winter month. December 2004 was 2.2C below normal nationally, though I wonder if a winter month with exactly the same weather pattern would also be 2.2 below normal, as cold southerlies are more frequent in winter anyway.

At the NIWA site from this link you'll find a MSLP anomaly map for December - it's quite impressive.

http://www.niwa.co.nz/ncc/cu/2005-01

[tich]

At the NIWA site from this link you'll find a MSLP anomaly map for December - it's quite impressive.

Thanks - it certainly is impressive. BTW I wonder how many winter months in NZ have been over 2C below normal nationally? I guess we'd have to go back many decades to find one.

[RWood]

At the NIWA site from this link you'll find a MSLP anomaly map for December - it's quite impressive.

Thanks - it certainly is impressive. BTW I wonder how many winter months in NZ have been over 2C below normal nationally? I guess we'd have to go back many decades to find one.

I can look that up at home - have a copy of NZ temp series (expensively acquired, but don't get me started on the regime of charging for information that should be in the public domain, as it used to be...). Not allowed to pass actual data on, but indirect statements like the answer to your question should be OK.

[tich]

I must add that winter months with alot of cold southerly outbreaks may not end up with monthly means too far below normal if the outbreaks are of a cyclonic nature - too much unsettled weather can prevent night-time minimums from getting too low. (as in August 1992 which was 'only' about 0.8C below normal) August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

From old NZ Gazette monthly summaries, I've read that June 1972 was very cold, with a weather pattern (several very cold southerly outbreaks) similar to the one I described in the 1st post. I believe the national average temperature for that month was about 1.5C below normal.

[RWood]

I must add that winter months with alot of cold southerly outbreaks may not end up with monthly means too far below normal if the outbreaks are of a cyclonic nature - too much unsettled weather can prevent night-time minimums from getting too low. (as in August 1992 which was 'only' about 0.8C below normal) August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

From old NZ Gazette monthly summaries, I've read that June 1972 was very cold, with a weather pattern (several very cold southerly outbreaks) similar to the one I described in the 1st post. I believe the national average temperature for that month was about 1.5C below normal.

From memory (I have a series of those gazette extracts) June 1972 SW flows were not as cyclonic as Dec2004 - plenty of frosts and sharp snowfalls, but also many clear days and lowish rainfall totals in many areas - will check that out as well. The archetypal bitterly cold month last century, with snow as for north as Kaitaia, was July 1939.

[RWood]

I must add that winter months with alot of cold southerly outbreaks may not end up with monthly means too far below normal if the outbreaks are of a cyclonic nature - too much unsettled weather can prevent night-time minimums from getting too low. (as in August 1992 which was 'only' about 0.8C below normal) August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

From old NZ Gazette monthly summaries, I've read that June 1972 was very cold, with a weather pattern (several very cold southerly outbreaks) similar to the one I described in the 1st post. I believe the national average temperature for that month was about 1.5C below normal.

From memory (I have a series of those gazette extracts) June 1972 SW flows were not as cyclonic as Dec2004 - plenty of frosts and sharp snowfalls, but also many clear days and lowish rainfall totals in many areas - will check that out as well. The archetypal bitterly cold month last century, with snow as for north as Kaitaia, was July 1939.

[RWood]

I must add that winter months with alot of cold southerly outbreaks may not end up with monthly means too far below normal if the outbreaks are of a cyclonic nature - too much unsettled weather can prevent night-time minimums from getting too low. (as in August 1992 which was 'only' about 0.8C below normal) August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

From old NZ Gazette monthly summaries, I've read that June 1972 was very cold, with a weather pattern (several very cold southerly outbreaks) similar to the one I described in the 1st post. I believe the national average temperature for that month was about 1.5C below normal.

From memory (I have a series of those gazette extracts) June 1972 SW flows were not as cyclonic as Dec2004 - plenty of frosts and sharp snowfalls, but also many clear days and lowish rainfall totals in many areas - will check that out as well. The archetypal bitterly cold month last century, with snow as for north as Kaitaia, was July 1939.

On checking: June 1972 6.8C (-1.8 from current 30-year normal); June 1941 6.6, back to 19th century for anything colder for June. June 1972 MSLPs were not unduly low, but plenty of snowfalls and severe frost. Rainfall below avg. except Otago and Southland, ditto for sunshine.

July 1939 averaged only 5.8 (-2.2 from 30-yr), and more notably MSLP at W'gton was only 1001.1 - a rare combination of extreme coldness and very low pressures - I was told that this requires an unusually cold Tasman sea. There were colder Julys still in 19th century (down to 5.0!!)

[RWood]

I must add that winter months with alot of cold southerly outbreaks may not end up with monthly means too far below normal if the outbreaks are of a cyclonic nature - too much unsettled weather can prevent night-time minimums from getting too low. (as in August 1992 which was 'only' about 0.8C below normal) August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

From old NZ Gazette monthly summaries, I've read that June 1972 was very cold, with a weather pattern (several very cold southerly outbreaks) similar to the one I described in the 1st post. I believe the national average temperature for that month was about 1.5C below normal.

From memory (I have a series of those gazette extracts) June 1972 SW flows were not as cyclonic as Dec2004 - plenty of frosts and sharp snowfalls, but also many clear days and lowish rainfall totals in many areas - will check that out as well. The archetypal bitterly cold month last century, with snow as for north as Kaitaia, was July 1939.

On checking: June 1972 6.8C (-1.8 from current 30-year normal); June 1941 6.6, back to 19th century for anything colder for June. June 1972 MSLPs were not unduly low, but plenty of snowfalls and severe frost. Rainfall below avg. except Otago and Southland, ditto for sunshine.

July 1939 averaged only 5.8 (-2.2 from 30-yr), and more notably MSLP at W'gton was only 1001.1 - a rare combination of extreme coldness and very low pressures - I was told that this requires an unusually cold Tasman sea. There were colder Julys still in 19th century (down to 5.0!!)

[tich]

June 1976 was similar to June 1972, though not as cold (despite 1 exceptionally cold southerly blast, with snowflakes even in parts of Auckland). I believe August 1981 was about a degree below normal, but probably due to persistently cold weather, rather than very cold outbreaks. July 1995 was very cold in the South Island, but not so much in the north of the North Island and so nationally was 0.9 below average. Some very cold winter months are due to very frosty spells instead of cold southerly outbreaks, eg July 2001.

August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

It would interesting if NIWA could compile separate statistics for the 2nd half of August - I guess it could easily have been one of the coldest 2nd halves of August on record for NZ.

[RWood]

June 1976 was similar to June 1972, though not as cold (despite 1 exceptionally cold southerly blast, with snowflakes even in parts of Auckland). I believe August 1981 was about a degree below normal, but probably due to persistently cold weather, rather than very cold outbreaks. July 1995 was very cold in the South Island, but not so much in the north of the North Island and so nationally was 0.9 below average. Some very cold winter months are due to very frosty spells instead of cold southerly outbreaks, eg July 2001.

August last year was significantly colder than average (0.8C), but there were some spells of mild westerlies in the 1st half, even though the 2nd half brought incessant cold southerlies.

It would interesting if NIWA could compile separate statistics for the 2nd half of August - I guess it could easily have been one of the coldest 2nd halves of August on record for NZ.

I would rate June 1976 as more "miserable" than June 1972 - much cloudier skies. And Aug 1981 had a max for Kelburn of only 12.9, very cloudy with night temps. not very low. In fact it concluded a very damp/wet cloudy 1981 winter for many places - whereas in July 1995 we (W'gton) had an overnight snowfall in middle of the month (stranding some hill suburb dwellers for a couple of hours, including us, because of icing that followed), followed by a couple of weeks of SW air and sunny skies almost every day. I think the latter half of Aug 2004 would be the coldest for decades, but I was in Aust. at the time.

[tich]

There were colder Julys still in 19th century (down to 5.0!!)

And probably even colder ones prior to the 19thC ('Little Ice Age'), but no-one was around to take readings. Maybe there was some Maori memory of extreme events, passed down by oral tradition, eg one story I've read somewhere refered to an old man in the late 19thC telling about his childhood in the 1820s, and mentioning that snow fell for 8 days at a low level village in southern Hawkes Bay.