The reports here summarise weather events and climate news, including a round-up of their media coverage. They are archived in the relevant day's Daily Weather Summary to help make it a more complete record of the day's events. Timeliness of the reports is entirely at the mercy of my available time so, for the most up-to-date information, make good use of my media links here.
|Thursday 27 September 2018
| The BoM's Climate Outlook for October to December offers little relief from above normal daytime temperatures (top) and generally dry conditions (bottom) across the nation, although the areas in white are likely to see 3-month rainfall fairly close to average. BoM.
Thu 27 Sep 2018 Bureau issues dismal outlook for next three months. The Bureau's Climate Outlook for the three months from October to December issued today brings little hope of relief from above average temperatures and below average rainfall for much of the country.
The solid red covering most of Australia at left indicates that the Bureau's climate forecasting model gives an unusually high 80% chance of average maximum temperatures exceeding the median across the period. It's rare to see such a broad area given such a high probability. Nights are also forecast to be warmer than average, although coastal areas of the NT, QLD, western VIC and southeastern SA will be closer to average.
The rainfall outlook is not so dramatically bad, although the large orange to brown areas of the map have moderate to high chances of below normal rainfall. There are, however, large areas of white, especially in NSW and across the north of the country, where the outlook for rainfall is close to normal.
The Bureau retains the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) at neutral, but says that "current observations and model outlooks indicate El Niño and a positive IOD could develop in spring."
Full details are in the Climate Outlook*, the Outlook video*, and a briefer archived version which is here.
Tue 25 Sep 2018 Wadeye NT smashes "dry" season records. Port Keats Airport, just outside the town of Wadeye, 200km NE of Wyndham WA, received a remarkable downpour this afternoon 25th with 43.4mm falling in under an hour to 1520CST. A wet season-like 36.4mm thundered down in the 20 minutes to 1450CST. In its 16 years of operation, the top daily September fall at the airport's weather station has been 12.6mm back in 2003, while its wettest whole month of September on record was 2016 with 15.8mm. Port Keats' average September rainfall is 3.1mm while their median is a mere 0.4.
Earlier in the day, Darwin was also hit by a downpour that gave 19.2mm in 21 minutes to 0100CST, for a storm total of 29.6. That's not so unusual for Darwin as it's farther north, but still an early arrival for the stormy season.
Despite these symptoms of an early build up to the wet, the Bureau's latest Weekly Tropical Climate Note says there is a strong likelihood that rainfall across most of northern Queensland and the Northern Territory will be below average during the October–December period.
Thu 27 Sep 2018 First southern hemisphere tropical cyclone named over a month before the season starts. The first tropical cyclone this season was named Liua by the Fiji Meteorological Service this morning 27th. Andrew Miskelly's animation of Himawari-8's visible imagery soon after daylight this morning EST shows the cyclone getting its act together just south of the Solomon Islands. The normal southern cyclone season runs from November to April, but sea surface temperatures in the area of 28 to 30°, over a degree above normal, are pushing the season forward. Liua is currently at Category 1, which it is expected to maintain as it moves south then west, weakening below cyclone strength on Saturday and posing no threat to Australia.
Sun 23 Sep 2018 Warm weather spreads south in WA. The hot weather that usually develops in spring in the far north of WA has started early this season, with the 40° mark being reached three times already - 40.2 at Fitzroy Crossing on the 4th, 40.0 at Wyndham on the 7th and 40.0 again at Kalumburu on the 23rd, all in the Kimberley. While these are September sizzlers, they're not that far above the September average, just 2 or 3°, but unusual for so early in the month.
However, that heat is being drawn south, and Sunday 23rd saw overnight minimum temperatures 6 to 9° above the September average through central and central southern WA while daytime maxima built to 8 to nearly 13 above the norm across most of the southern third of the state away from the coast. Kalgoorlie-Boulder Airport had the warmest night relative to average - 17.6° or 9.6 above, while Munglinup West, also in the Goldfields, sweated in a top of 32.5°, 12.7 above their September mean. Temperatures in parts of the state's SE rose into the mid 30s.
Sun 23 Sep 2018 Snow season second best in 14 years. Barring an unlikely late-season dump, the greatest depth of snow this winter measured by the Snowy Hydro at Spencer Creek, between Perisher Valley and Charlotte Pass, was 224.6cm on 22 August. in the past 14 seasons, only last year has seen a greater depth when a half-metre September snowfall gave an unusually late peak of 240.9cm on 20 September. The average greatest depth over the seasons from 1954 to 2017 is 197cm while the median is 186cm. Snowy Hydro measures the snow course every Thursday, and updates its full set of graphs promptly - rest your cursor on the trace for each weekly reading.
Sun 16 Sep 2018 A weekend of wild weather for southern states. The weekend of 15/16 September produced a smorgasbord of serious weather with, or in the wake of, a strong cold front that moved across the south of the continent from Friday. In the cold, dry air behind the front in WA, Saturday morning set new minimum temperature records for September (and in the cases of Ongerup and Newdegate for any month) bringing severe frosts in the South West that significantly damaged crops.
In SA and VIC, Sunday brought the coldest morning this late in the year for many years or decades as examined by Brett Dutschke on WeatherZone. Further cold records fell, as did 24-hour wind records in NSW where dust was raised in the state's west. Both Saturday and Sunday saw temperatures well above normal ahead of the front and well below normal behind, as well as some high wind gusts on the Saturday as it passed through SA and the southeastern states. The Guardian noted that the Snowy Mountains Highway on Sunday had the dubious distinction of being closed at one end by bushfire while nearly shut down at the other end by snow.
|Thursday 20 September 2018
Bushfires rage in WA, NT, QLD and NSW
Thu 20 Sep 2018
The Australian northern fire season runs from April to November, while the southern fire season runs from October or November (sometimes earlier) to April. We're now in the overlap season, where fires can be burning anywhere in Australia; in fact, all states and territories except the ACT have had bushfires during the past 48 hours.
Fires have been burning the full length of the coast and nearby ranges in New South Wales over the past week, exacerbated by warm, dry, windy weather ahead of several fronts. The largest is the Yankees Gap Road fire 25km NW of Bega. It has been burning for a month in the South East Forest National Park near Bemboka and as of mid-afternoon today had burnt through 19,118 hectares (191 sq km). The fire was at emergency level on Sat 15th, closing the Snowy Mountains Highway overnight into the 16th.
In Queensland, fires have also been burning the length of the coast from Brisbane to Cooktown. Two reached Prepare to Leave level today. ABC News reported that QLD Fire and Emergency Services have attended over 2,500 bushfires since the beginning of August. With drought conditions across large parts of QLD, fire authorities say there will be more instances of "subterranean fires", where a possibly small surface fire smoulders in a tree trunk then burns slowly through its root system. These fires are hard to find, hard to put out, and are likely to pop out days or weeks later and start another fire.
There have been dramatic fires on long fronts in Western Australia, such as this one (and here) south of Broome which briefly closed the Great Northern Highway on Tue 18th. Fires continue to burn in the Kimberley, Pilbara, Interior and the state's South West.
In the Northern Territory, as in large parts of QLD and northern WA, it is the dry season, and enormous scrub fires are part of life. About half the land between Darwin and East Arnhem Land burns every year, Joshua Fischer from Bushfires NT tells ABC Darwin in this detailed article on the north's dry-season fires. There have been total fire bans from Darwin south to Litchfield and sometimes SE to the Gulf of Carpentaria each day this week except Wednesday.
Bushfire links to bookmark
Thu 20 Sep 2018
Here are a national set of bushfire warning and information sites. They are permanently available in the links section of AWN, along with links on bushfire management and histories of major bushfires under Severe Weather > Bushfires.
Latest official bushfire warnings and information are available here: ACT | NSW | VIC | TAS | SA | WA | NT | QLD.
My Fire Watch is an Australia-wide map showing current fires, past burnt areas and recent lightning strikes. It, and its summary of national fire alerts, is not intended to replace the detailed and timely warnings from state authorities, but gives a useful national overview. It is the result of research collaboration between Landgate (the Western Australian Land Information Authority) and Edith Cowan University.
Another good resource is NAFI, the North Australia and Rangelands Fire Information website. It provides detailed maps of recent and past fire scars as well as current and recent hot spots in QLD, NT, and most of WA and SA. It has many excellent tools derived from satellite technology.
|Saturday 15 September 2018
1845AEST Mangkhut crosses Luzon and heads for China. Category 5 Super Typhoon Mangkhut crossed the far NE coast of Luzon in Cagayan province at 0400 AEST, 0200 Philippines time, this morning with winds at landfall averaging 260km/h with gusts to 320km/h according to JTWC estimates. The typhoon crossed the island remaining inland and parallel to the north coast before entering the South China Sea about 8 hours later. This satellite animation from Andrew Miskelly shows Mangkhut from 2100AEST Wednesday 12th, maintaining a near-perfectly circular eye right up to landfall after which the eye rapidly filled and the deep convection surrounding it began to seriously degrade as the typhoon crossed the island.
Initial press reports (Reuters, AFP) gave some information, though focussed on backgrounders due to a lack of hard detail because of communications loss with areas closest to the typhoon. A government official in Tuguegarao, the capital of Cagayan, told Reuters "Almost all of the buildings here have been damaged, the roofs were blown away. There has been no electricity supply ... communications [are] also down. We’ve received reports that many trees were uprooted and electric posts toppled and are blocking the roads. This makes the clearing operations really difficult." It will be some time before a detailed picture of damage emerges.
| The darkness of approaching night is advancing from the right in this visible image of Category 5 Super Typhoon Mangkhut at 1720AEST Friday 14th. The northern Philippines island of Luzon, on which Manila is located bottom left, will see the arrival of Mangkhut around sunrise on Saturday, when it crosses the NE coast before moving west and parallel to the north coast through the day. JMA Himawari 8 processed by Weatherzone.
2350AEST Super Typhoon Mangkhut close to landfall. While US media presence has seen Florence grabbing most of the headlines, Typhoon Mangkhut is by far the more powerful and dangerous cyclone, and will be landing on the eastern shores of Luzon, the main northern island of the Philippines, early Saturday 15th morning AEST. The image at left shows the sun setting on Friday on the huge eye of the cyclone, which I estimate as 65km in diameter, as it churns relentlessly towards the northern tip of Luzon. The Philippine capital, Manila, is in the bottom left of the image.
This morning, NASA posted this visible light image of Mangkhut at sunrise, while this infrared image of the typhoon, showing its progress in the 8 hours up to sunrise, clearly shows its dramatic and perfectly-formed eye.
Major press today have covered preparations in the Philippines and the arrival of cyclonic weather. Among the stories are these from AFP, Reuters and Al Jazeera. Apart from winds gusting to 250km/h and torrential rain, a storm surge "that could reach four storeys high" is expected in places, a spokesman for local civil defence authorities, Michael Conag, told AFP. He added this combination "could destroy houses, especially the makeshift houses. Those are the ones most common in coastal areas."
Press estimates of the number of people at risk vary wildly, from 4 million in Fairfax Media to 10 million, sourced to "authorities", in Al Jazeera. The Global Disaster Alert and Coordination System (GDACS) puts the exposed population* at a much higher 58.6 million, but that includes all countries touched by the typhoon.
| Hurricane Florence at 2302AEST Friday 14th , about two hours after it made landfall just east of Wilmington, North Carolina. It is tracking WSW, parallel to the coast before turning to the W. Movement is expected to continue very slowly, before it turns N. NWS
2330AEST Florence makes landfall. Hurricane Florence made landfall at 2115AEST Friday (0715 Friday local time) at Wrightsville Beach, a suburb of Wilmington, North Carolina. Wilmington's population is 120,000. The barometer fell to 958hPa at Wrightsville Beach as the Category 1 hurricane passed. Reuters noted this in this 2300AEST article, saying that the National Hurricane Center (NHC) indicated sustained winds near the centre were 150km/h. 440,000 properties were without power.
NWS cautions that, despite its low category rating, Florence's sheer size and slow movement will produce "feet of rain with inland flooding and up to 13 feet of storm surge". As of now, National Weather Service (NWS) radar estimates that 100 to 300mm of rain had fallen so far in coastal areas from the South Carolina border north to Cape Hatteras. Bands of heavy rain are pushing inland and have now reached about 200km towards the Appalachian Mountains in the west of the state.
1600AEST Hurricane Florence close to landfall. A weakened yet still dangerous Hurricane Florence is edging very close to landfall on the southern North Carolina coast just north of Wilmington, as shown by the Newport/Moorehead radar. On the same radar, if you choose Storm Total, under Rainfall, you will see that radar-derived rainfall totals have already hit 4 to 6 inches (100 to 150mm) along the coast NE from Wilmington to Cape Hatteras, with over 10 inches (250mm) in places. The rain is pushing steadily inland toward the Appalachian Mountains to the NW. For a broader view, use the loop under Long Range Images.
|Thursday 13 September 2018
2000AEST Super Typhoon Mangkhut remains Category 5 as it approaches the Philippines. Mangkhut appears to have peaked around 0700AEST this morning 13th with sustained winds (one-minute average) estimated at 290km/h and gusts to 350km/h. It was over open water at that time, and is expected to reduce intensity to Category 4 when it hits the northern end of Luzon, Philippines, during Saturday morning AEST. Sustained wind shortly before landfall is forecast to be 250km/h with gusts to 300km/h. Interaction with Luzon will reduce wind speeds to 205 with gusts to 250 by late morning as the typhoon is passing over the island, dropping it to Category 3.
The UK Met Office posted this animation of Mangkhut, known in the Philippines as Ompong, about 3 hours ago and this image showing where it is headed just now. Again, the size of the typhoon will cause widespread harm as it is 700 to 900km across. The Red Cross (IFRC) posted this Information Bulletin on the situation and the preparations it is making yesterday. There are good summaries of the situation on ABC News and in The Guardian.
1900AEST Dramatic imagery from NOAA of Florence. NOAA's latest Loop of The Day features this dramatic animation of Hurricane Florence's advance on the US east coast yesterday morning 12th local time. The scale of the hurricane compared to the Carolinas it is approaching is awe-inspiring in this imagery from the USA's GOES-16 satellite.
1505AEST Hurricane Florence update. The latest NHC Forecast Discussion issued 1300 Australian EST indicates storm surge and flood rainfall forecasts remain the same, but significant changes in the structure and environment of Florence have weakened it to a borderline Category 2/3 system. The good news is that landfall is likely to be delayed until late Friday morning and winds will be relatively lighter at that time (sustained speeds of 150km/h, or strong Category 1), though cover a larger area. The changed track of the Hurricane makes landfall more likely in southern North Carolina.
Edited details are:
...the convection on the southern side of the storm has been disrupted, and reports from an Air Force Reserve Hurricane Hunter aircraft indicate the eyewall now wraps less than 50 percent of the way around the center...The convection seems to have been affected by 20-25 kt of southerly vertical wind shear, most of which appears to be due to strong winds between 200-250 mb...The central pressure has risen to 957 mb, and the maximum 700-mb flight-level winds reported so far are 103 kt. Based on the latter data, the initial intensity reduced to a probably generous 95 kt [which is on the boundary between Category 2 and Category 3 (Major)].
...During the next 12-36 hours, the hurricane is expected to turn toward the west-northwest and west with a decrease in forward speed as it moves into an area of weakening steering currents near and over the southeastern United States. The new forecast track now brings the center onshore in southern North Carolina near the 36 h point [0100 Saturday AEST, 1100 Friday US EDT]. After landfall, the cyclone should move slowly [W to WSW for 1½ days then turn NW to N] through the Appalachian Mountains...
...sea surface temperatures near 29C [and a return to reduced upper wind shear] would allow a last chance for strengthening before landfall, but because of the storm structure and its size, it] would likely be slow to respond to the more favorable environment. The pre-landfall part of the intensity forecast thus calls for little change in strength, but given the uncertainties the confidence in this is low. After landfall, Florence should gradually weaken during the 36-48 h period while the center is near the coast, then weaken more quickly when the center moves farther inland.
While Florence has weakened below major hurricane intensity, the wind field of the hurricane continues to grow in size. This evolution will produce storm surges similar to that of a more intense, but smaller, hurricane, and thus the storm surge values seen in the previous advisory are still valid. The threat of rainfall has also not diminished, and these impacts will cover a large area regardless of exactly where the center of Florence moves.
1230AEST Seasonal Outlook Update out. The BoM's mid-month update and video for the Seasonal Outlook is now available, and unfortunately promises more of the same:
- Below-average rainfall likely for large parts of the country
- Day and night-time temperatures likely to be warmer than average
- While the El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are currently neutral, observations and model outlooks indicate El Niño and a positive IOD could develop in spring
If you're reading this after September,
the archive summary version is here. The BoM's Climate Outlooks are now produced using the much higher-definition ACCESS-S model, developed by the Bureau in collaboration with the UK Met Office. Here's an interesting blog on the improvements you'll see.
1100AEST Hurricane Florence. The good news in the NHC Forecast Discussion issued 0700 Australian EST is that Florence has somewhat weakened rather than strengthened, but the bad news is that at the same time it has become larger. Here's the main part of their notes. The latest Forecast Discussion for Florence is here. EDT in the USA is 14 hours behind Australian EST.
If you're not up to speed on developments, see the analysis I posted yesterday.
Data from an Air Force Reserve hurricane hunter aircraft along with satellite imagery and various intensity estimates indicate that Florence has weakened instead of strengthening. However, while the hurricane hasn't strengthened in terms of peak winds, the inner-core and outer wind fields have continued to expand, resulting in an increase the cyclone's total energy, which will create a significant storm surge event. The upper-level outflow remains impressive and is still expanding except toward the south.
Florence is moving toward the northwest or 315/14 kt. The new 12Z global and regional model runs have come into much better agreement on Florence moving steadily northwestward around a strong ridge located between Bermuda and the U.S. mid-Atlantic region for the next 48 hours or so. By late on day 2, Florence is forecast to approach the southern portion of the North Carolina coast, then slow down considerably and turn westward within collapsing steering flow, with a very slow westward motion near the coasts of North and South Carolina continuing into Friday and Saturday. Corrected-consensus models HCCA and FSSE remain very close to each other and are quite similar to the simple consensus model TVCA. Therefore, only a slight eastward shift was needed to the previous forecast track through 36 hours or so, mainly due to the more eastward initial position based on the reconnaissance fixes. At 48 hours and beyond, no significant changes were required to the previous advisory track, which still shows Florence moving slowly westward across South Carolina and western North Carolina on day 4, followed by a slow northward motion up the Appalachian mountain chain on day 5.
A narrow window of opportunity remains during the next 24 hours or so for Florence to strengthen a little when the hurricane passes over the warmer SSTs and deeper warm water/higher upper-ocean heat content associated with the Gulf Stream, and low vertical shear conditions of 5-10 kt will aid in any strengthening process. However, significant strengthening is not anticipated due to Florence's large and expanding inner-core wind field. By 36 h and beyond, decreasing ocean heat content along with the slowing forward speed of Florence will likely produce cold upwelling beneath the hurricane, inducing a gradual weakening trend. When Florence moves over the shallow coastal shelf waters in 48-72 h, land interaction and more significant upwelling are anticipated, which should further enhance the weakening process. The NHC intensity forecast remains near the higher statistical guidance through 48 hours, then follows the trend of the decay SHIPS model after that time.
Although the maximum winds are expected to weaken a little more, Florence is still expected to remain a dangerous major hurricane as it approaches the coast. The threat to life from storm surge and rainfall will not diminish, and these impacts will cover a large area regardless of exactly where the center of Florence moves.
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