Tropical Cyclone Yasa radar image
Radar image of Tropical Cyclone Yasa at 02:30Z December 17, 2020, (9:30 p.m. EST December 16), approximately four hours before it made landfall on Fiji’s Vanua Levu Island. Yasa was undergoing an eyewall replacement cycle, where the inner eyewall was collapsing. (Image credit: Fiji Meteorological Service)

Tropical Cyclone Yasa made landfall on Fiji’s Vanua Levu Island (population 136,000) at 6Z (1 a.m. EST) Thursday, December 17, as a high-end category 4 storm with 145 mph winds, according to the Joint Typhoon Warning Center (JTWC). Yasa is the second-strongest cyclone on record to make landfall in Fiji, behind Tropical Cyclone Winston, which hit Fiji’s Koro Island as a category 5 storm with 180 mph winds in 2016.

Yasa peaked as a low-end category 5 storm with 160 mph winds with a central pressure of 914 mb at 0Z Wednesday, and maintained category 5 strength through 12Z Wednesday. In the hours leading up to landfall, the cyclone underwent an eyewall replacement cycle (ERC), a process common in intense cyclones, in which the eyewall shrinks, grows unstable, and collapses, with a new eyewall forming out of an outer spiral band. This process weakened Yasa’s peak winds by 15 mph, but increased the storm surge, as the region of ocean experiencing hurricane-force winds expanded. Yasa’s impact on Fiji’s Vanua Levu Island is likely to be devastating.

Figure 1
Figure 1. MODIS visible satellite image of Tropical Cyclone Yasa at category 4 intensity with 150 mph winds at approximately 21Z December 16, 2020. The Fijian Islands are to the southeast of the storm. (Image credit: NASA Worldview)

Forecast for Yasa

At 10 a.m. EST December 17, Yasa was a low-end category 4 storm with 130 mph winds, headed southeast at 16 mph. High wind shear of 20-25 knots and declining sea surface temperatures along the cyclone’s track will result in steady weakening. Yasa’s track will take it near some of the smaller Fijian islands, but no major populated areas are likely to experience a direct impact from the cyclone.

Yasa is the southeast Pacific’s second category 5 storm of 2020

How climate change is making hurricanes more dangerous

Yasa is the second category 5 storm observed in the Southeast Pacific in 2020, joining Tropical Cyclone Harold, which devastated Vanuatu and Fiji in April. In only one other year (1998) have two category 5 cyclones been observed in the Southeast Pacific. Since reliable satellite data for the Southeast Pacific became available in the 1980s, there have been 15 category 5 storms in the basin, as classified by the JTWC. Yasa is the earliest category 5 on record in the Southeast Pacific, where the cyclone season straddles calendar years. The next earliest, Cyclone Zoe, peaked as a Cat 5 on December 27, 2002.

Bob Henson contributed to this post.

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Posted on December 17, 2020(12:46pm EST).

Topics: Weather Extremes
17 Comments
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Art
Art
29 days ago

im hearing possible a big cooldown for Florida by Xmas thru possibly the weekend, might be a freeze northern florida in some places..stay warm all.

Skyepony
30 days ago

The weak bow echo fell apart. Has a little lightning..
comment image?w=600&h=620

Art
Art
1 month ago

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
934 AM EST Sun Dec 20 2020

.UPDATE…
A cold front is expected to push through the tonight. However,
ahead of the front we are under a warm and moist atmosphere. The
Nature Coast has already seen a few light showers this morning and
there is currently a batch of light to moderate rain in the Gulf
that will slowly head towards the coast in the next few hours.
Except for the rain we are not expecting any stronger storms and
hi res models are showing it breaking up as it pushes on land.

The more concerning thing to watch is any prefrontal convection
in the late afternoon and evening hours. Right now we are looking
at a brief opportunity where the upper level winds, stability,
and the warm and moist air advection is favorable for a few
stronger storms right along the coast. The big question is how
much prefrontal convection will reach this area when is it primed
to produce the stronger storms. Also how will the light to
moderate shower activity now effect the atmosphere since models
are not handling that area very well. Because of these factor SPC
has now put the coastline in West Central Florida in a marginal
risk of severe weather. Right now no major changes needed to the
forecast.

&&

daddyjames
daddyjames
1 month ago

Merry Christmas – yes I know I have been a stranger. But I still am.

Jexpat
Jexpat
1 month ago
Reply to  daddyjames

Strange days indeed.

Skyepony
1 month ago

Chilly 42F in Melbourne, FL this morning.

Changing the Government Furlough Watch to a Government Furlough Warning. It’s not a given but we could see the Federal Government shut down at the end of today. Getting together a spending bill with covid relief and all has not happened. There is less talk of a Continuing Resolution and more about a brief shutdown this week end. Also seeing yesterday updated furlough effects being put out there. The last one was so long some changes were made like federal employees could add dependents to their insurance during furlough and such. https://www.govexec.com/pay-benefits/2020/12/guide-pay-and-benefits-during-shutdown/170826/

Last edited 1 month ago by Skyepony (mod)
Skyepony
1 month ago
Reply to  Skyepony

Govt funding including pay for NWS/NOAA employees and the continued updating of some of the weather data sites that many of us use has been extended through the weekend.

Skyepony
1 month ago

Yasa..
comment image

Skyepony
1 month ago

Can’t seem to see anything newer than 2 months ago on the last disqus thread.

Yasa’s models are still pretty spread out.
http://wind.mit.edu/~emanuel/temp1t.png

Last edited 1 month ago by Skyepony (mod)
Skyepony
1 month ago
Reply to  Skyepony

Looks like if you comment or wait for someone to comment disqus corrects to present time.

Yalewang
Yalewang
1 month ago

Disqus seems to be down again.

Gr8lakebreeze
Gr8lakebreeze
1 month ago
Reply to  Yalewang

It’s time-warping all over the place. That thread might be on its last legs. If so, it was one hell of a run!

Last edited 1 month ago by Gr8lakebreeze
greiner3
greiner3
1 month ago

Never thought I’d type “It sucks to be in Fiji”.

Paul J Pickett
Paul J Pickett
1 month ago

Why is Yasa moving east? I thought all tropical cyclones generally head west until coriolis turn them east. Yasa seems to be heading east and turning west.

jeffs713
jeffs713
1 month ago
Reply to  Paul J Pickett

Southern hemisphere – almost everything is switched due to the Coriolis effect.

jiiski
jiiski
1 month ago

Thanks, Dr. Masters and Bob Henson. I’m glad to read that Yasa won’t impact many people. Whew!

Michael Field
Michael Field
1 month ago

Yasa is in south west Pacific….