Dan Reno
14th Jan 2011, 19:51
Extreme high pressure system may affect Alaska aviation
by Jeff Richardson / [email protected] Fairbanks Daily News Miner
Jan 11, 2011
FAIRBANKS — A severe high-pressure system in the Interior and Arctic this week is expected to cause a strong temperature inversion and air pressure high enough to affect some airplane instrument systems.
The high-pressure system has already pushed barometric pressure readings above levels of 31 inches of mercury in some parts of the Arctic, and it is expected to do the same in parts of the Interior by tonight or Wednesday, according to the National Weather Service. That’s notable because most airplane altimeters don’t read accurately under those pressure conditions.
Bob Fischer, a National Weather Service forecaster, said that means airplanes could have altimeter readings as much as several hundred feet above their true altitude in parts of the state today.
The false readings won’t necessarily affect aviation. Pilots in the affected areas will need to fly when visibility is good, and those conditions are expected throughout the week.
“This is really no cause for panic,” Fischer said. “We’ll have severe clear everywhere — pilots will be able to make visual approaches day and night.”
In Fairbanks, which is 454 feet above sea level, the high pressure system isn’t expected to set any records, the weather service reported. In Barrow and Deadhorse, places closer to the center of the system and nearer sea level, records could be set.
Fairbanks-area residents will experience the high-pressure system in the form of a big temperature inversion between the valleys and hills. Fischer said temperatures in the hills will be 20 to 30 degrees warmer than in valleys, where a cold snap could dip temperatures down to 30 below zero by later this week.
Those conditions will be accompanied by winds of as strong as 30 mph on hilltops, according to the NWS forecast. As a result, the weather service has issued a winter weather advisory that is in effect through 6 a.m. Thursday.
Residents are advised to watch for blowing snow and possible poor visibility in areas such as Cleary Summit, Wickersham Dome and Murphy Dome. Places with elevations of less than 2,000 feet should not be affected.
Contact staff writer Jeff Richardson at 459-7518.
Read more: Fairbanks Daily News-Miner - Extreme high pressure system may affect Alaska aviation (http://www.newsminer.com/view/full_story/10959712/article-Extreme-high-pressure-system-may-affect--Alaska-aviation?instance=home_news_window_left_top_1#ixzz1B2qBi2bP)
by Jeff Richardson / [email protected] Fairbanks Daily News Miner
Jan 11, 2011
FAIRBANKS — A severe high-pressure system in the Interior and Arctic this week is expected to cause a strong temperature inversion and air pressure high enough to affect some airplane instrument systems.
The high-pressure system has already pushed barometric pressure readings above levels of 31 inches of mercury in some parts of the Arctic, and it is expected to do the same in parts of the Interior by tonight or Wednesday, according to the National Weather Service. That’s notable because most airplane altimeters don’t read accurately under those pressure conditions.
Bob Fischer, a National Weather Service forecaster, said that means airplanes could have altimeter readings as much as several hundred feet above their true altitude in parts of the state today.
The false readings won’t necessarily affect aviation. Pilots in the affected areas will need to fly when visibility is good, and those conditions are expected throughout the week.
“This is really no cause for panic,” Fischer said. “We’ll have severe clear everywhere — pilots will be able to make visual approaches day and night.”
In Fairbanks, which is 454 feet above sea level, the high pressure system isn’t expected to set any records, the weather service reported. In Barrow and Deadhorse, places closer to the center of the system and nearer sea level, records could be set.
Fairbanks-area residents will experience the high-pressure system in the form of a big temperature inversion between the valleys and hills. Fischer said temperatures in the hills will be 20 to 30 degrees warmer than in valleys, where a cold snap could dip temperatures down to 30 below zero by later this week.
Those conditions will be accompanied by winds of as strong as 30 mph on hilltops, according to the NWS forecast. As a result, the weather service has issued a winter weather advisory that is in effect through 6 a.m. Thursday.
Residents are advised to watch for blowing snow and possible poor visibility in areas such as Cleary Summit, Wickersham Dome and Murphy Dome. Places with elevations of less than 2,000 feet should not be affected.
Contact staff writer Jeff Richardson at 459-7518.
Read more: Fairbanks Daily News-Miner - Extreme high pressure system may affect Alaska aviation (http://www.newsminer.com/view/full_story/10959712/article-Extreme-high-pressure-system-may-affect--Alaska-aviation?instance=home_news_window_left_top_1#ixzz1B2qBi2bP)