This week, a screaming hot Pacific basin hurled six tropical cyclones northward. These cyclones spawned off the back of a building monster El Nino which is predicted to reach strong-to-record intensity by later this year. They also contributed to setting a record for number of cyclones formed in the Northern Hemisphere so early in the year. In the Western Pacific, one of these Cyclones — Typhoon Chan Hom — slammed into Shanghai on July 10th and 11th, delivering high waters, high winds and floods.
Now, another cyclone — Typhoon Nangka — is venting its fury on Japan.
(Nangka takes aim on Japan in this MODIS satellite shot. Image source: LANCE-MODIS.)
A few hours ago, Nangka made landfall near Muroto City. Over the past 24 hours, Nangka had weakened from a category 3 storm packing 115 mile per hour intensity, blustering ashore as a minimal Typhoon with 75 mile per hour maximum sustained winds. Nangka is interacting with a frontal boundary, which interfered with the storm’s circulation even as it injected massive amounts of moisture into Nangka’s encircling thunderstorms. This increased moisture loading — likely also enhanced by global temperatures that are now in the range of 1 C hotter than 1880s averages together with moisture bleeding off an anomalously warm Pacific — is resulting in forecasts for up to 1 meter of rainfall as Nangka continues to churn over Japan.
Nangka’s eyewall and strong south to north winds are running smack into Japan’s ocean facing mountains. The combined high moisture loading and the lifting action of winds running up the mountains are pumping up Nangka’s thunderstorms to extraordinary intensity. Weather radar from earlier today showed hourly rainfall rates peaking at an extreme 3.15 inches per hour near Shikoku. There, after hours of this intense pounding, rainfall totals have hit as high as 23 inches (UPDATE: Kamikitayama village had reported 27 inches of total rainfall as of 5:20 AM local time.)
These heavy rains are expected to continue for the next 24-48 hours with very severe additional totals predicted for a number of regions. Expected new rainfall amounts include:
- Kinki and Tōkai: 600 millimeters (~24 inches)
- Shikoku island: 600 millimeters (31 inches)
- Kantō region: 400 to 500 millimeters (16 to 20 inches)
- Chūgoku region: 300 to 450 millimeters (12 to 16 inches)
- Tōhoku region: 250 to 350 millimeters (10 to 14 inches)
Extraordinary additional rains that will bring with them the risk of severe flash flooding and landslides to the mountainous slopes of Japan.
Nangka At Tail End of Warm, Wet Wind Invasion of Arctic Later This Week
As Nangka continues northward, it will become wrapped up in a trough, helping to feed a larger synoptic pattern of moisture and air flow from south to north. The trough, in turn, is projected to rush northward into the Bering Sea. By Monday, a dipole pattern set up between the trough running through the Bering and the Ridiculously Resilient Ridge to the east will pull warm air up from the tropical Pacific and catapult it toward the already weakened ice of the Bering, Chukchi and Beaufort seas.
(Long wave north to south synoptic pattern projected to draw warm air and water into the Pacific side of the Arctic over the next 3-6 days. Image source: Earth Nullschool.)
In the above image from Earth Nullschool and based on GFS models, we can see the strong south to north synoptic wind pattern predicted to set up. Flowing from a region near Hawaii, these winds are predicted to pull tropical airs over thousands of miles, run them up through the Bering and into the High Arctic.
In conjunction with this warm air invasion, a head of hot water now at a +5 C positive anomaly in the Chukchi will be driven northward running directly into highly fractured and disassociated ice floes. It’s a weather pattern that is a continuation of consistent warmth hitting the sea ice on the Pacific side of the Arctic. One that is driven both by El Nino and by a human greenhouse gas based amplification of heat in the polar zones. This combination has generated a kind of Achilles heel for Arctic sea ice on the Pacific side for 2015. With another hit coming to this area and with sea ice already in a somewhat tenuous state due to the continued impacts of warm air near Greenland, a Greenland high and a related dipole continuing to nudge the ice toward the Fram Strait, risks rise that current sea ice measures ranging at 4th lowest in area and 7-9th lowest in extent could take a further tumble.
Hat tip to Greg