NH Fall / SH Spring 2022 Discussion Thread

Possible midnight high today. High today at the South Jakarta PWS (so far as of 3pm) is 28.0C/82.4F at midnight, no 80F+ since just past 2am.

Currently 26.0C/78.8F just past 3pm.

www.wunderground.com/dashboard/pws/ISOUTH1189/graph/2022-11-17/2022-11-17/daily

Massive inversion in Lapland today. Enontekiö Airport at 380 m ASL recorded -25.9C this afternoon, while Kittilä Laukukero at 760 m ASL just 42 km away recorded a high of 8.7C.

Yesterday did end up having a midnight high at the South Jakarta PWS

First ice day of the season here too, high was 29 (-2 c) at 1 AM. Tomorrow will be the first official ice day though due to the moronic 7 PM day, because it was above freezing yesterday evening.

Had a decent snowfall, with 2.0” (5 cm) falling as of 7 PM. Kinda tapered off since though so will end up well on the low end of the forecast unfortunately.

After single digit lows the next two nights it will warm back up to near average by the start of next week.

-4.3c, light snow at 17:00, the coldest day so far.

Independence day here in Latvia. One of the coldest in recent years, high will be 0.7C in Riga because of the previous night, but today during the day it has not risen above -0.4C. Cloudy with little sunshine, some flurries, but no snow sticking on the ground.

Had a nice little burst of snow tonight.

Another 1.0” of snow fell after 7 PM yesterday for a storm total of 3.0” (8 cm). Definitely at the very low end of the forecast but I will take the snow and not complain.

24/7 today (-4/-14 c), by far the coldest day so far this season. First official ice day and the first single digits. Also the last cold day for awhile with temps nearing 60 by the end of next week.

Australia’s Flood Crisis – Three Years in the Making with a Volcanic Twist
( source: Anthony Cornelius Meteorologist )

The weather and climate of 2022 has truly been a year like no longer – and many of us will never have experienced a year like it before in our lifetime. Australia is no stranger to floods – I often say average rainfall is really just the balance between drought and flood, but 2022 really has been exceptional in terms of flooding. In fact, more BoM issued flood warnings have been issued in 2022 than the previous four years combined for the same period!
In February 2022, Northeast NSW was devastated by the worst flooding on record, while billions of dollars worth of damage was done in Southeast Queensland as nearly two metres of rain fell in just four days. However it didn’t stop there – a month later Lismore had another major flood, while further flooding redeveloped in Southeast Queensland during May.
Since then we’ve seen rainfall and flooding spread southwards with areas of NSW and Victoria hit hard, not to mention Sydney recorded its wettest year on record weeks ago (meaning even if another drop doesn’t fall, it’ll still be the wettest year on record).
We’ve heard a lot about the current climate patterns contributing to the rain and flooding – but 2022 in that it goes beyond that. While both a La Nina and negative Indian Ocean Dipole have been operating, if we want to look as to why this year has been particularly bad we need to wind the clock back a couple of years.
In 2020 a La Nina developed which produced above average rainfall to large parts of the country. However flooding initially was limited because 2019 was actually the driest year on record for many locations.
For much of Australia (particularly eastern Australia), 2021 was a substantially wetter year than 2020 – mostly thanks to a second La Nina. 2021 was actually a significant year for flooding – dwarfed now by the incredible flooding of 2022. However unlike heavy rainfall events (which are largely independent from each other), flooding is not. That is, one flood event can impact the next flood event – and what we’ve actually seen is years of above average rainfall culminate to widespread major flooding.
It's easy to forget when we hear on the news that inland areas of NSW have had 50mm in a day – for many of these locations, this is the average monthly rainfall! To top it off, these types of rainfall events have been occurring sometimes in as little as 7-10 days apart. The result are catchments that become super saturated and highly susceptible to flooding. During dry periods, much of this rain not only soaks into the ground, but it fills up empty dams and dry creek and river beds. This means that the first band of rainfall after a dry period often doesn’t do much to the big country river systems. But after time, all the dams fill up, all the creeks run, and any further rain that occurs simply runs off. While 50-100mm may not sound like much, this effectively could be producing impacts of rainfall more than double this simply because the ground is so saturated and there’s nowhere for this rainfall to runoff!
For those interested, I’ve gathered some comparison charts. These include:
- Graph of BoM issued flood warnings (showing an extraordinary number being issued for 2022) - this excludes duplicates and rivers that only went minor
- Graph of Forbes rainfall (used this location due to it being one of the most significantly impacted locations)
- Soil moisture content for October 2021 compared to October 2022 (this year we started from a much the soil couldn’t soak up as much moisture as it did last year, which was also a significant flood and rainfall year (albeit more isolated)
- Maps of rainfall (as percentage of the mean) for 2020, 2021 and 2022 showing continued wet and above average rainfall (particularly for eastern Australia)
Finally – I will say there is some possibility that the Tonga volcanic eruption actually has contributed to the flooding scenario Australia. In 2019, the westerly wind belt in Australia was ‘turbo charged’ by a Sudden Stratospheric Warming event which caused westerly winds to bring dry conditions and horror bushfire conditions. In 2022, we saw a Sudden Stratospheric Cooling event which potentially was caused by the Tongan volcanic eruption. As this was an underwater eruption, it pushed incredibly high amounts of water vapour and particulates into the stratosphere. This has reflected the sunlight and caused this layer of the atmosphere to cool. The result has been a re-enforcement of a very prominent positive Southern Annular Mode for much of spring. This resulted in a large and prolonged period of easterly winds that helped block the more typical west to east patterns of troughs and fronts during September and October, meaning we saw trough systems sit through inland areas of Victoria, NSW and southern Queensland rather than reach the coastline. Recently this trend has changed a little which is good news – though without getting too far ahead of myself, I think all eyes will now be north through the tropics with indications of an early MJO burst in early December which could increase rain, storm and even tropical cyclone activity across far northern Australia. However, we’ll have to sit and watch this one further.
Until then – there remains good climate model agreement that this La Nina should weaken early next year which will hopefully provide some longer term relief on the rainfall front (though may eventually bring its own challenges because eventually we’ll get a dry period and there’s a lot of fresh vegetation thanks to all of the rainfall!)