2023 Tropical Storm Thread (Southern / Northern Hemisphere)

Deep subtropical low rapidly approaching New Zealand
( source: Weatherzone )

A rapidly deepening subtropical low is ominously approaching New Zealand’s North Island, with storm force winds and heavy rain already battering the Northland Peninsula.
This low has an interesting origin story; with Ex-Tropical Cyclone Lola colliding with a broad trough extending from the east Australian coast across the Tasman Sea towards NZ. The resulting low has since inherited the southward track from the remnants of Lola, while deepening quite rapidly on its approach to NZ.

^^Image: ECMWF forecast wind gusts at 7am Mon 30th October NZDT

Cape Reinga, on the far northern tip of the North Island, has already seen wind gusts above 120km/h this morning with several other stations recording wind gusts exceeding 100km/h. NZ’s MetService warns that winds may exceed 130km/h for exposed coastal areas, and reach 100km/h elsewhere for areas stretching from Northland Peninsula across to the Gisborne region in the country’s northeast.
MetService also warns that rainfall totals may reach 100-140mm, possibly as high at 170mm for the Gisborne region as the low edges closer. Most of this rain will fall between Sunday afternoon and Monday afternoon in northern areas, and between early Monday morning and Monday evening in the Gisborne region. In addition, several strong wind and heavy rain watches in place for other northern and central districts of the North Island. Thunderstorms are also a chance north from, and including Auckland and western parts of the Bay of Plenty district.

^^Image: ECMWF Forecast accumulated precipitation to 1am NZDT Wed 1st November

Auckland itself won’t escape the treacherous conditions. Winds will increase during Sunday night, and peak Monday morning, potentially exceeding 100km/h for the exposed coast and islands. Rainfall thankfully looks to be less intense with 40-80mm likely across NZ’s biggest city until Tuesday evening.
Winds and rain will ease for northwestern areas late on Monday, and focus in on the northeast coast on Tuesday as the low weakens and slides to the east. By Wednesday, the low will dissipate ahead of the next cold front bringing another burst of heavy showers late in the week.

Your Weather Channel - JWC
Good morning following up Justin’s post
Most models this morning have this future cyclone Jasper either hitting the coast or sliding down the coast which was our nightmare scenario last night
Here are four models this morning
Most models are also back on the big upper trough and low over south eastern Australia
As you can tell with the enhanced rain
IF this thing hits the coast could be from anywhere from Townsville to the NSW coast! Perhaps as a tropical depression by then
Here are the four models showing a westward push this morning
In order
ACCESS
ECMWF
CMC
GFS

Tropical Cyclone likely in Coral Sea this week
( source: Weathetzone )

A tropical cyclone is likely to track over the Coral Sea this week and may move closer to Australia’s east coast at some stage next week.
The satellite images below show a tropical low sitting over the Solomon Sea on Monday. This low is expected to develop into a tropical cyclone on Tuesday.

As this system looks set to become a tropical cyclone in the far northeast corner of Australia’s area of responsibility, it is expected to be named Jasper by the Bureau of Meteorology. This would be the first tropical cyclone of the season in Australian waters.

Before looking at the future movement of this system, it is important to point out that there is a high degree of uncertainty in the forecast beyond Wednesday. This makes it difficult to accurately predict its track and strength from Thursday onwards.

At this stage, most forecast models predict that the system will become a tropical cyclone on Tuesday before moving towards the south-southwest on Wednesday while strengthening.

According to the Bureau of Meteorology, the system has a high chance of becoming a severe tropical cyclone (category 3 or higher) from Thursday as it moves towards the south over the northeastern Coral Sea.

While this system is not expected to directly impact Australia’s mainland between now and Friday, there is a growing potential for it to track towards eastern Qld from this weekend or early next week. However, it is too far out to know whether this system will stay offshore or move over Australia's east coast. For now, anyone living south of Cairns should keep a close eye on the forecasts over the coming week.

The map below shows where the Bureau of Meteorology expect this system to be located on Monday, December 11, with the centre of the system expected to be located somewhere inside the red shaded area.

We will be watching this system closely over the coming week and providing daily updates on the potential threat for Australia via the Weatherzone News feed.

Jasper to become Australia’s earliest category 4 tropical cyclone in 18 years
( source: Weatherzone )

Severe Tropical Cyclone Jasper could become the earliest category four tropical cyclone in Australia's area of responsibility since 2005.
Cyclone Jasper formed over the Solomon Sea late on Tuesday before moving towards the south and gaining strength. By Wednesday night, Jasper had intensified into a category 3 severe tropical cyclone and the system is expected to reach category 4 strength on Thursday night.

If Jasper does reach category 4 strength as expected, it will be the earliest category 4 tropical cyclone in the Australian region for 18 years. The last cyclone that was stronger and earlier was Severe Tropical Cyclone Bertie, which reached category 4 in late-November 2005.

Jasper’s life as a category 4 tropical cyclone will probably only last a day or so before increasing wind shear (change of wind speed/direction with height) and an injection of dry air causes it to weaken from late Friday into the weekend, while moving towards the west.

This anticipated weakening is good news for communities living in eastern Qld because Jasper is expected to continue on a path towards the state’s east coast early next week.

While there is still a lot of uncertainty regarding Jasper’s strength and location beyond the weekend, there is growing model consensus that it will make landfall somewhere over the central or northern coast of eastern Qld. At this stage, landfall will most likely be between Cooktown and Mackay between Tuesday and Thursday, if the system does end up reaching the coast.

It’s still too early to be certain that Tropical Cyclone Jasper will make landfall and how strong it will be if it does. If you live in eastern Qld, be sure to stay up to date with the latest tropical cyclone advisories over the coming days.

Your Weather Channel - JWC
Good morning all
Jasper is re-intensifying as we speak. Current consensus is a Cat 2 at landfall which will be either directly over or just north of Cairns. However, as of the latest tech bulletin, the chance of it slowing up and sitting off the coast allowing it to build to a Cat 3 before crossing has gone from a slim chance to a real one.

Cairns and surrounding areas look to be in trouble with not only an average of 400-800mm falling but local falls of 1000mm aren't out of reach and a Category 2 possible Category 3 with a king tide is going to cause coastal inundation! Along with the rain.
We will keep an eye on this over the next 12 hours and keep you informed.

BOM’s latest take on it!
DESTRUCTIVE winds of up to 140 km/h are expected to develop between Wujal Wujal and Innisfail from early Wednesday morning.
GALES with DAMAGING WINDS of up to 120 km/h are expected to develop along the Queensland coast and adjacent ranges between Cape Flattery and Townsville, including Cairns, from today. These DAMAGING WINDS are expected to extend inland to Palmerville and Chillagoe after the cyclone has crossed the coast on Wednesday.

GALES with DAMAGING WINDS may extend as far north as Cape Melville on Wednesday, depending on the movement of Jasper.
A separate severe weather warning is current for DAMAGING WIND GUSTS for coastal and island areas between Cape Upstart and the Whitsunday Islands; refer to that product for more information.

HEAVY RAINFALL which may lead to FLASH FLOODING is forecast to develop from early Wednesday morning between Cape Flattery and Ingham. Six-hourly totals between 100 to 150 mm are likely, with isolated falls of 250 mm possible along the coast and adjacent ranges. 24-hourly rainfall totals between 150 to 250 mm are likely, with isolated falls up to 350 mm possible.
A flood watch is current for the North Tropical Coast, parts of the Cape York Peninsula and Gulf Country.
As the cyclone approaches the coast, a STORM TIDE is expected between Cooktown and Townsville on the high tides today and Wednesday. Large waves may produce minor flooding along the foreshore. People living in areas likely to be affected by this flooding should take measures to protect their property as much as possible and be prepared to help their neighbours.

Tech Bulletin
REMARKS:
Tropical Cyclone Jasper has developed convection with lightning to the north of
the low level centre. Position is reasonable based on animated IR imagery, the
edge of radar, and local observations.
Dvorak analysis is based on MET and PAT giving a FT and CI of 3.0. Current
objective aids: ADT 35 kts, AiDT 34 kt, DPRINT 34 kts, DMINT 35 kt (from 0901
UTC), SATCON 44 kt (all 1-minute wind speeds). Surface observations at 18 UTC:
south-southeasterly 38 kt at Flinders Reef, west-southwesterly 30 kt at Holmes
Reef, northerly 35 kt at Willis Island. Current and previous observations
indicate gales remain in at least three quadrants. Intensity held at 45 knots.
Jasper is moving to the west-northwest towards the north tropical Queensland
coast under the influence of a low-level and mid-level ridge to the south.
There is good consensus in guidance for Jasper to cross the coast between
Cooktown and Innisfail, most likely around or just north of Cairns, on
Wednesday.

CIMSS wind analysis indicates 8 knots of southerly shear. Shear is expected to
remain low as Jasper moves under the axis of an upper shortwave trough. SSTs
remain warm at approximately 27-28C, and this moderately favourable environment
continues along the forecast track until landfall on Queensland's North
Tropical Coast on Wednesday. A mitigating factor will be upper outflow, which
will be limited as the system moves to the west of the upper shortwave. Based
on these environmental conditions and NWP, some intensification is therefore
expected prior to landfall, most likely beginning Tuesday morning, and a
category 2 landfall remains the expectation. If the system moves slower than
forecast and crosses overnight Wednesday or Thursday, a chance remains of a
severe category 3 crossing.

In the longer term, model guidance continues Jasper's westerly track across
Cape York Peninsula and into the Gulf of Carpentaria. Redevelopment over the
Gulf of Carpentaria is possible next weekend

The circulation is very clear on the radar.

Not uncommon to cross Cape York Peninsular and reform in the warm shallow soupy waters of the Gulf of Carpentaria. Then cross the east coast of the NT and bring good rains to the base of the Top End.
One of the less likely scenarios is any sorta direct impact on Darwin, although a few models are suggesting this could happen in about a weeks time.

Ex TC Jasper continues to drop copius quantities of rain over far North QLD
KURANDA:


COOKTOWN:


CAIRNS: