Recent six- to 10-day temperature outlooks by the National Weather Service’s Climate Prediction Center (CPC) have been off by a mile, and CPC Senior Forecaster Ed O’Lenic admits the atmospheric situation currently is the “kind that forecasters dread.”

The atmosphere is a “very unforgiving place,” said O’Lenic in an interview with NGI. “When it is doing things that we understand, we are very happy. When it is doing things that we don’t understand, or that are very changeable, we are not very happy and neither are our customers. It’s Chapter 10,005 in the facts of life.”

The CPC’s six to 10-day outlooks were pretty good up to about the middle of November. Since that time the forecasts have had serious problems. The weather has transitioned from a pattern that was cold in the West and warm in the East to one that is a lot more mixed in the East, and West as well, and very little has been captured by CPC forecasting.

In fact, the only things that the National Weather Service has predicted correctly over the last couple of weeks have been the recent warmth in New England, the above normal temperatures around Lake Michigan and in Kansas, and the near normal temperature forecast from Minnesota and the Dakotas south through Colorado, New Mexico and North Texas. The rest of CPC’s recent predictions have been a bust. And it’s not likely to improve in the near term.

“Things have not settled down,” O’Lenic said. “I would say fasten your seatbelts. It’s going to be a bumpy ride.”

He insists there is no permanent lapse in CPC prediction skills. Over the last couple of decades, the skill level of the six to 10-day forecasts has been slowly improving. “The trend line is going up,” he said. “Obviously in the last 10 years or so, it looks like the skill has sort of taken a dip and kind of leveled off through the 90s and now it appears to be going back up again. That has happened because of the types of weather patterns that we’ve had. Some are more predictable than others. Also, models have been coming into use and going out of use, and it’s hard to pinpoint what exactly causes these variations.”

There’s nothing out of the ordinary about what has been going on recently with the CPC’s forecasts, he said. The CPC periodically does a “sanity check” on its forecast models. What it’s seen lately is that correlations to historical patterns have not been very high. “That indicates that the atmosphere has been pretty much continuously in some kind of transition,” said O’Lenic.

The CPC’s seasonal forecast, which currently shows extremely large areas where there are “equal chances” of above or below normal temperatures, also has been subject to the same kinds of atmospheric problems, he said.

“When you have an El Nino or La Nina going on, you have a lot fewer options that the atmosphere has and that gives the forecasters an edge.

“If you look at an animated loop of what’s been happening in the Northern Hemisphere over the last month or so, around the first of November there was a ridge in the East and a trough in the West, but since then there has been a lot of variability. The ridge and trough broke down and it’s just been musical upper air height anomalies ever since then,” he said.

“El Nino reduces the options that the atmosphere has, and when we have neutral conditions like we have now virtually all of the variability is internal to the atmosphere; it has nothing to do with being forced by something like El Nino. When the pattern breaks down like this and it doesn’t settle down into a single familiar pattern, not only are you out of luck, but we’re out of luck too. The best we can do is make our forecasts wimpier and less committal.”

Unfortunately, O’Lenic admitted, the CPC didn’t catch onto all this until just recently — “until we put out a week’s worth of pretty lousy forecasts. We just didn’t catch on to the fact that the pattern was going to be so variable and relatively unpredictable.”

What it means going forward, however, is that there should be very little confidence in short-term and long-term forecasting. “This is the kind of situation in a probability forecasting system where you’ve got to pretty much go as weak as you can.”

The latest six- to 10-day forecast calls for below normal temperatures over the Southeast and Gulf Coast region and above normal temperatures across the northern third of the country and the states west of the Rockies except Southern California, where temperatures are expected to be normal. Normal temperatures are expected over a band extending from the Mid-Atlantic west through the Midcontinent and south over West Texas (https://www.cpc.ncep.noaa.gov/products/predictions/610day/610day.01.gif). Or not. It might be wise to take it with a grain of salt.

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