Extended Winter Outlook: CPC

Yesterday we talked about the late Fall-early Winter outlook for temperature and precipitation. Today, we'll look at the extended Winter outlook, also issued by the Climate Prediction Center (CPC).

(Images: NOAA)

As explained previously, these outlooks are primarily based on the El Nino-Southern Oscillation trend, which is currently in El Nino. These long-range Winter outlooks, which cover the Winter months (December into March), are related to the North American weather trends that tend to result from the equatorial Pacific waters being warmer-than-average. The warmer waters alter the tropical rain patterns, with a domino effect into the jet stream pattern over the Pacific into North America. When the jetstream shifts, that also shifts the track low-pressure systems take, making some regions drier than average, while others can expect a wetter Winter than average. With the jet hugging the southern parts of the U.S., this should bring more precipitation to that region. It will also result in cooler conditions for the Southeast into the Mid-Atlantic. This long-range outlook coincides with the three-month outlook we talked about yesterday, supporting the expected continuation of the El Nino trend. For Virginia, this could mean a wetter, cooler Winter, which would thus mean the potential for more winter weather events (translated: kids, that means maybe more snow days!). Look for Chief Meteorologist Zach Daniel's Snow Outlook to be released in early December.

Double Dip of Record Cold Highs

The high temperature for Thursday of 54 degrees set a new record for the coldest low, or what is called a record low maximum. The old record low maximum was 56 set in 1939. It's very likely that tomorrow's high will set another record, making it back-to-back record-setting days. The record low maximum for tomorrow is 54 set in 1940, and we are forecasting a high of just 49. Those 70s next week can't get here too soon.

Late Fall-Early Winter Outlook

Today, the Climate Prediction Center issued its long-range forecast for November through January, based primarily on the El Nino-Southern Oscillation trend.
Here's the Temperature Trend, where blue shades indicate cooler-than-average temperatures, and the orange shades warmer-than-average:


And the Precipitation Trend, where green shades indicate wetter-than-average conditions expected, and the tan shades indicate drier-than-average conditions:


The equatorial Pacific west of South America has been in El Nino conditions (meaning warmer-than-average ocean surface temperatures) for months now, and looks like it will continue through the North American winter months as well. This has meant in previous El Nino Winters that the Southeast tends to be a little cooler-than-average. Here is an example of a strong El Nino event occurring during Winter (January-March):


So based on this information, it appears that the Commonwealth can expect a cooler-than-average start to Winter this year, and when you combine that with precipitation...well, that can mean more winter weather precipitation events in our future! As mentioned in the previous blog entry, today just to our north, New York and Pennsylvania are getting a slightly early start on their winter weather season with a heavy wet snow falling today into Saturday. Could this be a sign of things to come for us as those colder temperatures creep farther South over the next month? We'll be keeping you ahead of the storm.