You are here: Home Projects & Resources Environment Global Warming Pacific/North American Pattern (PNA)

Pacific/North American Pattern (PNA)

Pacific / North American Pattern (PNA) – The Pacific/ North American teleconnection pattern (PNA) is one of the most prominent modes of low-frequency variability in the Northern Hemisphere extratropics. The positive phase of the PNA pattern features above-average heights in the vicinity of Hawaii and over the intermountain region of North America, and below-average heights located south of the Aleutian Islands and over the southeastern United States.

The PNA pattern is associated with strong fluctuations in the strength and location of the East Asian jet stream. The positive phase is associated with an enhanced East Asian jet stream and with an eastward shift in the jet exit region toward the western United States. The negative phase is associated with a westward retraction of that jet stream toward eastern Asia, blocking activity over the high latitudes of the North pacific, and a strong split-flow configuration over the central North Pacific.

The positive phase of the PNA pattern is associated with above-average temperatures over western Canada and the extreme western United States, and below-average temperatures across the south-central and southeastern U.S. The PNA tends to have little impact on surface temperature variability over North America during summer. The associated precipitation anomalies include above-average totals in the Gulf of Alaska extending into the Pacific Northwestern United States, and below-average totals over the upper Midwestern United States.

Although the PNA pattern is a natural internal mode of climate variability, it is also strongly influenced by the El Niño/ Southern Oscillation (ENSO) phenomenon. The positive phase of the PNA pattern tends to be associated with Pacific warm episodes (El Niño), and the negative phase tends to be associated with Pacific cold episodes (La Niña).

Ensemble Mean PNA Outlook

Current Conditions:

The daily PNA index correpsponds to the  PNA patterns, which vary from one month to the next. Click here for the methodology used to calculate the daily PNA index.

The daily PNA index for the past 120 days. Each daily value has been standardized by the standard deviation of the monthly PNA index from 1950 to 2000 interpolated to the day in question.

Pacific/North American Pattern Observed & ENSM Forecasts

http://www.cpc.noaa.gov/products/precip/CWlink/pna/pna.sprd2.gif

Source: http://www.cpc.noaa.gov/products/precip/CWlink/pna/pna.shtml

Links

 

Document Actions
Keep up to speed on changes and significant news from OSS

Subscribe to the OSS 'Leading Edge'

* indicates required
Exposing the Climate Hoax

There is a hoax going on, but it's not what some claim. Learn now to separate fact from fiction and reason from rhetoric to learn who is really 'tricking' you.

This book includes critical economic facts and key percentages that put the climate debate in a whole new light.

It's All About the Economy
20" Dobsonian Telescope
The Centrist Party
Join The Centrist Party. America need politics that make sense. Economy, Energy, Environment, Education, Healthcare, Security and Political Reform. Join the Party and let's do our best to 'Make a Meaningful Difference'.
Join Now
About this site:

Powered by Plone with the Notre Dame Skin.

 

Microscope/Camera