Visible satellite image of Typhoon Nuri on Tuesday. (NASA)
Powerful Typhoon Nuri is expected to generate a ripple effect of chilly U.S. weather in November, after the storm deepens to potentially record-setting pressures in the Bering Sea later this week.
Typhoon Nuri has weakened since Monday, now the equivalent of a category 4 hurricane. Remarkably, the typhoon remained a category 5 for 24 hours, and maintained its 180 mph winds for at least 18 hours. Nuri is now tied with Typhoon Vongfong as the strongest storm of 2014.
But Nuri’s superlatives likely won’t end there. Over the next few days, Nuri is forecast to track north through the West Pacific, losing its tropical cyclone characteristics, and interacting with a strong jet stream. By the time the low pressure system reaches the Bering Sea, west of Alaska, it is forecast to have deepened to a pressure less than 920 mb — on par with some of the deepest cyclones on record. The lower the pressure, the more intense the storm is.
Mean sea level pressure forecast for late Friday night snows Nuri’s remnants deepening to a pressure of 916 mb west of Alaska. (weatherbell.com)
On Monday night, the European model was forecasting the cyclone to drop 36 mb in 18 hours to an incredible low pressure of 916 mb. This would likely be the lowest pressure ever recorded in the Bering Sea — the previous record for Alaska is 927 mb at Dutch Harbor in 1977. It would also come very close to the lowest extratropical pressure on record for any location, which is 913 mb, set in the North Atlantic in 1993.
Heads up: #Bering Sea, #GreatCircle shipping, and coastal communities. A big storm is developing Friday. #AKwx @NWS pic.twitter.com/KltWg0o2v8
— NWS Anchorage (@NWSAnchorage) November 3, 2014
Combined with some other atmospheric patterns that favor cold weather in the eastern U.S., Nuri’s extremely low pressure is poised to kick-start a domino effect on weather in the Northern Hemisphere over the next few weeks. In particular, it will spur a parade of cold air outbreaks across the central and eastern U.S. in November.
The storm’s deep low pressure will build a strong ridge in the eastern Pacific and over western North America. This, in turn, will force cold, Arctic air to surge south in the central and eastern U.S. over the next few weeks.
Upper air temperature animation over North America through November 12 shows a series of Arctic air surges in the eastern U.S. (weatherbell.com modified by CWG)
The first in a series of strong cold fronts is expected on Friday, while forecast models suggest a deeper push of cold air can be expected next week.
D.C. Forecast: Chilly weather on the way by Friday
Arctic Oscillation forecasts also warn of cold times to come. The Arctic Oscillation (AO) is an indicator of the strength of the polar jet stream, which can effect how much Arctic air reaches the U.S. A positive AO suggests that cold, Arctic air will stay north. A negative AO, or weaker polar jet stream, opens the door for that cold air to spill south into the lower 48. Global models are predicting a dramatic shift into negative territory for the AO over the next week.
The GFS forecast of the Arctic Oscillation through November 12 shows a dramatic dive into negative territory, opening the door for cold air outbreaks across the U.S. (weatherbell.com)
“The typhoon does appear to be contributing to the amplifying pattern by phasing with a trough coming off of East Asia,” said CWG’s Matt Rogers. “Amplifying that trough in turn amplifies more ridging downstream over the North Pacific toward Alaska.”
In addition to the powerful Bering Sea storm, favorable activity in the tropics and a warm pattern in the very high levels of the atmosphere are likely playing a part in the AO’s plunge to negative. All of these factors are expected to unite and deliver chilly November temperatures to the eastern U.S. The good news is that while this pattern does favor cold air outbreaks, we will have periods of warmer weather in between.
