NH Fall/SH Spring 2021 Discussion Thread

There we go

This is a nice map to track cold or warm fronts. See the strong cold front diving into the deep south for Friday. 60's down to Florida:

digital.weather.gov/

It is a bit slow to load. 

It's 4C as of 7:00am today, not often that we're that much above freezing at this time of the day in late October. Probably the last mild-ish morning of the season.

Cool, wet and windy in southwestern Australia
( Source: Weatherzone )
A strong cold front passing through WA today will cause temperatures to plummet across southwestern WA today. The front will also elevate winds, and bring large surf to the western coastline during the next few days.

The satellite image below shows the cold front crossing the nation's southwest on Monday morning. The front is marked by the thick band of cloud over southwestern WA.

To the south of this front is a large mass of speckled clouds, which is an indication of the very cool air on its way to WA.

The image below shows the stark contrast in airmass temperatures to the east and west of the front, with temperatures behind the front plummeting for a number of days.

Perth's maximum temperature during the next 3 days will fail to exceed 18 degrees, with temperatures 5-6 degrees cooler than the October average.

Moderate to strong west to southwesterly winds will also increase the wind chill early this week, making these temperatures feel even colder. Temperatures are set to warm up just in time for the weekend after a very cool week for the west coast.

A very long fetch of west to southwesterly winds moving over the ocean for a number of days is set to bring large waves to the southern coastline of WA. Waves of 3-4 metres are predicted for the next 2-3 days along the coastline south of Carnarvon.

In contrast to the cold air heading towards WA from the south, the state’s north if experiencing hot, dry and windy conditions that are bringing Severe top Catastrophic fire danger to the states north and interior.

Severe to catastrophic fire danger is forecast for the East Pilbara Coast, West Pilbara Coast, East Pilbara Inland, Ashburton Inland, Gascoyne Inland, Goldfields, Eucla, South Interior and Esperance Shire Inland fire weather districts today.

Mostly cloudy with evening thunderstorms, high/low 75/58 @ LGA and 72/59 @ Farmingdale.

So far 0.21” of rain in the bucket. Much more to come, 3-5” expected.

Massive temperature discrepancies across Australia's southern coastline
( Source: Weatherzone )
Temperature discrepancies of more than 20 degrees are being experienced along the vast extent of Australia’s southern coastline on Tuesday morning, due to two distinct weather systems.

The first system:

In the west, a cold front that passed through southwestern WA late on Sunday into Monday has now progressed eastwards, reaching the South Australian border in the early hours of Tuesday morning.

Ahead of it, northerly winds are dragging down hot dry air from the interior, which is why much of South Australia will experience temps in the 30s or above today, while many localities in southern WA will struggle to reach the mid teens.



The cold front's strength was well illustrated by the town of Eucla – WA's easternmost locality – where temperatures reached the mid-30s on Monday. The mercury was still 25.5°C at 3:30 am before rapidly shedding eight degrees in an hour to be 17.5°C at 4:30 am.
Meanwhile as we write this story, Eucla was sitting on a mild 19°C while Nullarbor, just a couple of hours east over the SA border, was already on 30°C. Some coastal locations in SW WA were hovering at only 8°C or 9°C.
Temperatures could exceed 40°C in northern SA in the next day or two, with Oodnadatta tipped to reach 41°C on Wednesday, which would be its hottest reading for spring 2021 to date. The town of 200 residents is famous for Australia's highest recorded temperature (50.7°C in January 1960).
Adelaide is expected to reach 30°C both today and tomorrow. Its hottest day in October 2021 to date was 25.7°C, although an early spring warm day of 31.2°C was recorded on September 2.
The second system:

Meanwhile in the southeastern corner of the country, skies will stay mostly clear but maximums today will be kept in the mid to high teens in Tasmania and southern Victoria due to a low pressure system in the Tasman Sea funnelling cool southeasterly winds over the region.

The effects of that system will dissipate in the next 24-48 hours as the warmer weather moves across from the west.

Had an overnight low of 37 F (2.8 C), milder than its been. As of 7 am, it's 38 F (3.3 C) with a 32 F (0.0 C) dew point, high forecast today is forecast 54 F (12.2 C), with blustery SE winds at 15-25 mph (24-40 kph) with gusts up to 40 mph (64 kph).

Nice crisp fall night for SE Arizona

The HRRR shows an intense squall line coming through tomorrow afternoon.