Monitoring heat waves over Christmas

With the exception of Kununurra, W.A and the Riverina in southern NSW, all other areas will experience mild temperatures through until the middle of next week.

Heatwave forecast starting Saturday 9 January through to Wednesday 13 January 2020

About heat waves

Heatwaves are calculated using the forecast maximum and minimum temperatures over the next three days, comparing this to actual temperatures over the previous thirty days, and then comparing these same three days to the 'normal' temperatures expected for that particular location. Using this calculation takes into account people's ability to adapt to the heat. For example, the same high temperature will be felt differently by residents in Moree compared to those in Orange, who are not used to the higher range of temperatures experienced in Moree. The full forecast can be accessed here: http://www.bom.gov.au/australia/heatwave/

Climate in-brief

• Moisture levels and cloudiness remains high to Australia’s north with the Northern Coral Sea very warm, albeit with MJO forecast to appear in the Indian Ocean, away from Australia in the coming week.

• Very little in the way of cyclone activity expected in the coming fortnight, as waters cool to Australia’s north

• The Southern Annular Mode is maintaining its good form in moderately positive (wet) phase and predicted to remain so, - assisting moisture flow through NSW and S Qld areas.

• Multi-week models showing split fortunes for tropics and mid-latitudes, with some caution for large areas of Qld through January. On the other hand, consensus shows continued moisture for much if NSW and SE Qld over the coming 4 weeks.

• Temperatures to remain around normal or cooler throughout January, consistent with increased cloud cover and influence of the current La Nina.

The chart above shows higher-than-normal air pressure in Southern Australia for the last 30-days and lower air pressure to the NW.

Australian daily and weekly rainfall observations

Some handy falls confined to the coast and ranges in the last day or so. Click on the link for an updated map. http://www.bom.gov.au/australia/flood/?ref=ftr

Weekly rain shows some fantastic falls across the tropics, with the belated arrival of the much-touted 2020 la nina! the NSW north coast and ranges of NSW still in the storm track over xmas, along with the norther Territory and Western Australia.

Australian 7-day rainfall map courtesy http://www.bom.gov.au/climate/maps/rainfall/?variable=rainfall&map=totals&period=week&region=nat&year=2020&month=12&day=17

2020 year rainfall deciles

Fresh off the press this morning, rainfall deciles for the year show central NSW as the sweet spot for rain. Qld would have looked much worse if not for the great falls in the last week across the north.

Decile map courtesy BOM 1 January 2021

Monitoring heat waves over Christmas

Most areas will experience mild temperatures over the Christmas long weekend. A low intensity heatwave condition is forecast North and South of Cairns, with easing heat around Perth and persisting heat in Western Australia’s Central West.

Heatwave forecast starting Thursday 24 December through to Tuesday 29 December 2020

About heat waves

Heatwaves are calculated using the forecast maximum and minimum temperatures over the next three days, comparing this to actual temperatures over the previous thirty days, and then comparing these same three days to the 'normal' temperatures expected for that particular location. Using this calculation takes into account people's ability to adapt to the heat. For example, the same high temperature will be felt differently by residents in Moree compared to those in Orange, who are not used to the higher range of temperatures experienced in Moree. The full forecast can be accessed here: http://www.bom.gov.au/australia/heatwave/

Climate in-brief

• Moisture levels and tropical divergence remains high to Australia’s north, albeit with MJO predictions offering little in terms of strength and its next move.

• The Southern Annular Mode is weakly-moderately positive and predicted to remain so, - assisting moisture flow through NSW and S Qld areas.

• Multi-week models showing some signs of low-air pressure and moisture continuing into the second week of January. Shorter-term guidance is showing only sporadic and smaller totals throughout the forecast area - staying in touch with information when it comes to hand will be critical in the coming days

• Temperatures to remain around normal or cooler through until mid-January, consistent with the presence of the MJO to Australia’s north

The chart above shows higher-than-normal air pressure in SE Australia for the last 30-days and lower air pressure to the NW.

Australian weekly rainfall and relative landscape water balance

Some handy falls confined to the Great Dividing Range and western slopes of the ranges in the last 24 -48 hrs. Click on the link for an updated map. http://www.bom.gov.au/australia/flood/?ref=ftr

Weekly rain shows the NSW north coast and ranges being in the sweet spot, along with the norther Territory and Western Australia.

Australian 7-day rainfall map courtesy http://www.bom.gov.au/climate/maps/rainfall/?variable=rainfall&map=totals&period=week&region=nat&year=2020&month=12&day=17

Climate in-brief

• A moderately active MJO pulse is making its way eastwards along the equator towards Australia’s north, which has been difficult to track on the spider diagram “Evaluation of individual circulation and convective variables supports a robust MJO over the Maritime Continent” (NCEP 1 Dec).

• The Southern Annular Mode is back above zero, and is predicted to stay in the positive (wet) phase in the coming fortnight - assisting moisture flow through NSW and S Qld areas.

• Anomalous high pressure has been the feature off eastern Australia over the last month, with many eastern locations achieving decile 1-2 November rainfall (see map opposite and bottom right).

• Multi-week models showing consensus for a more general wetter-than-normal period 11-31 December. Shorter-term guidance is showing little enthusiasm for general rain events at this stage - staying in touch with information when it comes to hand will be critical in the coming days

• Temperatures to remain around normal or cooler for December, with recent heat wave activity abating.

The chart above shows higher-than-normal air pressure across eastern/northern Australia for the last 30-days.

Australian weekly rainfall and relative landscape water balance

Some handy falls in northern NSW and border rivers overnight. Isolated patchy falls elsewhere in S Qld, the big rivers area of NT and Kununurra also. http://www.bom.gov.au/australia/flood/?ref=ftr

November rainfall decile map shows a sorry tale of dry weather during La Nina 2020 - perfect for grain harvest, although summer crop and livestock producers would beg to differ.

Australian decile map courtesy http://www.bom.gov.au/climate/maps/rainfall/?variable=rainfall&map=decile&period=month&region=nat&year=2020&month=11&day=30

Climate in-brief

• Australia has found itself hostage to anomalous high-pressure (chart adjacent), with very little moisture transport from the tropics to inland areas, with the exception of isolated pockets along the coastline

• The Southern Annular Mode has tanked negative, which will not assist moisture inflow to central-eastern areas during the remainder of November, but the SAM is expected to move more positive (wet) in December

• With a benign MJO, very little tropical activity and subsequent cyclonic activity, however, the air pressure at Darwin has fallen to well below average this week

• Multi-week models showing consensus for a more general rain event ~4-14 December where guidance suggests the current stronger than normal air pressure anomaly will abate - enabling easterly moisture penetration into NSW and Qld

• Temperatures to remain around normal for the remainder of November, and

• Seasonal models for summer season not showing consensus for a typical La Niña rainfall signature, as some caution is recommended for N NSW and SE Qld areas, with the eastern half of Qld and SE NSW showing the most potential for higher-than normal rainfall.

The chart above shows higher-than-normal air pressure across eastern/northern Australia. The low pressure associated with the MJO has not propagated eastward, with cyclonic activity centred in the Bay of Bengal and western Indian Ocean.

Australian weekly rainfall and relative landscape water balance

Some handy falls in the big rivers area of NT and the gulf over the past week and smaller scattered totals elsewhere along the coast and ranges. http://www.bom.gov.au/jsp/awap/rain/

Water balance anomaly still shows a dry area in SW Qld, with areas along the NSW ranges still above average after reasonable october totals

Australian relative landscape water balance ‘upper soil’ courtesy BOM

Climate in-brief

• Very little going on in the Australian tropics with the MJO currently on the other side of the world. The latest NCEP reports states “The MJO is slow moving and weak, which the opposite of that expected during a La Niña”

• A continued positive surge by the Southern Annular Mode has kept some colours in the rain forecast, albeit not big totals anticipated for the month of November

• Multi-week models not showing consensus on rainfall today and not showing any real enthusiasm for decent totals through November, with rain-bearing systems mainly centred around the Fitzroy Valley, and the NSW Great Dividing Range as a consequence of moisture in-feed from a positive SAM

• Temperatures to remain around normal for the remainder of November, and

• Meet Dr Ali Theobald - what are the climatic influences on Australia’s biggest irrigation network? We investigate factors impacting inflow into the headwaters of the Snowy Mountains Scheme, supporting $5 billion in irrigation infrastructure.

The chart above shows humidity below normal across much of north and eastern Australia over the last 7-days, helping grain harvest but not summer crop establishment.

Australian weekly rainfall and relative landscape water balance

A spike in the SAM has helped activate moisture into SE NSW over the last week with little else to report for the remainder of Australia. http://www.bom.gov.au/jsp/awap/rain/

Water balance anomaly shows a dry area in SW Qld, which will hopefully get under a drop in the system coming off the coral sea this coming week

Australian relative landscape water balance ‘upper soil’ courtesy BOM

Farmer Forecast is going weekly on Fridays!

Dealing with boom-bust cycles and farming the moisture while its on: the next edition of Farmer Focus we meet Emerald (Qld) mixed-farmer, Nigel Burnett.

We have so much new content, that from today are splitting our fortnightly e-news into alternating weekly issues;

• This week (Week A); fresh analysis of climate drivers, forecast model surveys and meet the climate researcher / farmer focus; plus

• Next week (Week B); in depth current climate analysis and 9-day ECMWF rainfall forecast.

Climate in-brief

• An active MJO in phases 5-6 north of Australia has brought moisture to central and eastern parts of Australia in the past week;

• Multi-week models are favouring rain across eastern areas of NSW and Qld with another change expected through the mid-latitudes around mid-November;

• Seasonal models have wound back previously bullish probabilities for the coming three months, however, the majority of models are in agreement for wet conditions none-the-less; and

• Analysis - La Nina 2020-21: how does it compare to other events in the past?

The chart above shows humidity well above normal down the centre and eastern area of Australia at 3pm yesterday.

Australian weekly rainfall and relative landscape water balance

An active MJO has triggered some tropical moisture and rainfall to the centre and eastern parts of Australia. http://www.bom.gov.au/jsp/awap/rain/

Water balance anomaly shows a dry WA and parts of CQ and eastern tropics.

Australian relative landscape water balance ‘upper soil’ courtesy BOM

Climate in-brief

This weeks chart shows humidity well above normal down the centre of Australia.

• Conditions in the tropics, our major source of moisture, continue to be “disorganised” according to the latest NCEP update this week, as the atmosphere continues to realign with warmer tropical waters;

• The SAM index is finally weakly positive, assisting the formation of moist air into eastern Australian agricultural areas;

• 90-day SOI has exceeded La Niña thresholds (+8), and the air pressure at Darwin is now below normal for the first time this season;

• Multi-week models are favouring rain across southern areas and the ranges in the next 10-days. All other areas look to week 3-4 of October for moisture to arrive;

• Summer cropping analysis for La Nina years; and

• What does this years La Nina mean for our climate in 2021? - the latest research.

Australian weekly rainfall and relative landscape water balance

The air pressure at Darwin is finally below normal. Moisture has streamed down the inland over the last week.

Rainfall maps courtesy http://www.bom.gov.au/jsp/awap/rain/

The high pressure system in the Tasman Sea keeping eastern Australia dry, but the interior has been in the sweet spot.

Australian relative landscape water balance ‘upper soil’ courtesy BOM

Climate in-brief

This weeks chart is from CLIMATEAPP. It shows Griffith, NSW YTD rainfall ahead of median. Click the chart to go through to www.climateapp.net.au and choose your location in ‘hows the season?’

·       The 30-day SOI has exceeded La Niña thresholds (+9), although the rise in the index has been mainly associated with higher air pressure at Tahiti;

·       Multi-week models are favouring rain across all forecast areas in the coming weeks, although the sweet spot appears to be in SW Qld, central and southern NSW;

·       A survey of the latest global GCMs shows broad consensus for wetter-than-normal and cooler conditions between October and December; and

·       Measuring zones in the Niño and Indian Ocean Dipole regions shows a stronger signal from the Pacific Ocean, however the IOD seems to be making a late surge towards wetter conditions, helping spring rainfall prospects in NSW.

Australian weekly rain map

Rainfall maps courtesy http://www.bom.gov.au/jsp/awap/rain/

A positive spike in the SAM pushed some moisture into eastern Australian over the last week.

Climate in-brief

This weeks chart is from CLIMATEAPP. It shows MOREE, NSW YTD rainfall (RED line) ahead of median (Blue line). Click the chart to go through to www.climateapp.net.au and choose your location in ‘hows the season?’

• A dry air mass associated with a passing Rossby wave in the eastern Indian Ocean has wreaked havoc with a week ago wetter than normal multi-week forecast (NCEP report 22 Sep);

• The SAM index is predicted to plummet into a negative phase in the coming week, creating rainfall opportunities for Southern NSW, while other areas remain hostage to a drier airflow;

• 30-day SOI has exceeded La Niña thresholds (+9), although the rise in the index has been mainly associated with higher air pressure at Tahiti. The daily index shows this will continue, which is promising;

• Multi-week models are favouring rain across southern areas only. All other areas look to mid-October for the drier SAM pattern to break and tropical air masses to realign with La Nina signal and wetter IOD;

• A survey of the latest global GCMs shows broad consensus for wetter-than-normal and cooler conditions between October and December; and

• New crop research shows sorghum variety selection based on accurate seasonal forecasts can offer benefits to growers.

Australian weekly rainfall and relative landscape water balance

A positive spike in the SAM pushed some moisture into eastern Australian over the last week.

Rainfall maps courtesy http://www.bom.gov.au/jsp/awap/rain/

A land of extremes with some regions at the lowest 1% and others at the highest 1%. most cropping regions are looking for rain to finish winter crops - particularly wa

Australian relative landscape water balance ‘root zone’ courtesy BOM