Climate Prediction Center - Week 3-4 Outlook

Prognostic Discussion for Week 3-4 Temperature and Precipitation Outlooks
NWS Climate Prediction Center College Park MD
300PM EST Fri Dec 19 2025

Week 3-4 Forecast Discussion Valid Sat Jan 03 2026-Fri Jan 16 2026

Confidence in this week’s forecast is high, supported by strong model agreement and clear tropical-extratropical teleconnections. While the Madden-Julian Oscillation (MJO) recently re-emerged with enhanced convection over the Western Hemisphere, it is unlikely to play a significant role in the current outlook. Most dynamical guidance suggests this re-emergence will be short-lived, with the MJO signal weakening again over the next few days. Instead, the Pacific North American (PNA) pattern may potentially have a larger impact on North American temperature and precipitation patterns. Often associated with La Niña conditions, the negative phase of the PNA has been present since the beginning of December and is currently forecast to continue in the negative phase until at least the beginning of the forecast period. The Arctic Oscillation (AO) is also forecast to trend toward the negative phase in the next several days. However, this transition is marked by considerable uncertainty, as individual members of the GEFS and ECMWF ensembles show a large spread in their projections.

The large-scale circulation pattern shows strong agreement across major models, with 500-hPa geopotential height anomalies aligning with negative PNA conditions. This is most evident in the anomalous ridging over the Bering Sea and the anomalous troughing across the Northeast Pacific. However, model consistency decreases regarding the anomalous ridging over the Continental United States (CONUS). While a manual blend of dynamical and statistical models indicates weak positive height anomalies over the Southwest and Northeast, individual models offer varying solutions. The GEFS depicts stronger anomalies centered over the Southern Plains, whereas the CFS suggests weak negative anomalies over the Mid-Atlantic. Although this general circulation pattern persists through both Week 3 and Week 4, it is forecast to de-amplify during the latter week.

The Week 3-4 Temperature Outlook favors above normal temperatures for much of the CONUS. Probabilities are highest from the Great Basin to Texas where model guidance consistently shows ridging. The models also tilt toward below normal for northern North Dakota and Minnesota related to the anomalous troughing. Conversely, uncertainty is higher across New England where the forecast guidance is mixed on the sign of the anomalous circulation over the region. The dynamical models span the range of solutions for the region, including above, below, and near normal probabilities. Furthermore, the inconsistent AO forecasts add another layer of uncertainty to the sign of the temperature anomalies. As a result, Equal Chances (EC) of above or below normal temperatures are forecast for much of New England. EC is also indicated for parts of central California. Although anomalous ridging typically brings warmth, valley inversions, which have been persistent in recent weeks, could lead to localized colder-than-normal conditions despite the broader pattern.

The Week 3-4 Precipitation Outlook shows a continued likelihood of above normal precipitation for the Pacific Northwest. The dynamical models consistently predict an enhanced height gradient over the region, driving stronger onshore flow and increased moisture flux. This pattern is favored to continue through the entire Week 3-4 period. Elsewhere across the CONUS, probabilities tilt toward above normal precipitation for the Great Lakes and Ohio Valley regions consistent with the negative phase of the PNA and La Niña conditions. Drier conditions are indicated for the Southeast except for southern Florida where EC of above or below normal precipitation is forecast.

For Alaska, strong anomalous northerly flow associated with the ridge-trough pattern promotes a tilt towards below normal temperatures across the entire state with strongest probabilities along the southern coast. Below normal precipitation is favored for the southern coast due to the offshore flow.

Across the Hawaiian Islands, La Niña conditions, elevated sea surface temperatures, and strong model agreement all support above normal temperature probabilities. The dynamical model guidance also consistently indicates above normal precipitation chances.

Forecaster: Laura Ciasto

The next week 3-4 outlook will be issued on Friday, Dec 26, 2025

These outlooks are based on departures from the 1991-2020 base period

These are three category outlooks consistent with what is currently used for the monthly and seasonal forecasts.

The shading on the temperature map depicts the most favored category, either above-normal (A), below-normal (B), or near-normal (N) with the solid lines giving the probability ( >33%) of this more likely category (above, below, or near).

The shading on the precipitation map depicts the most favored category, either above-normal (A), below-normal (B), or near-normal with the solid lines giving the probability ( >33%) of this more likely category (above, below, or near).

In areas where the likelihoods of 2-week mean temperatures and accumulated precipitation amounts are similar to climatological probabilities, equal chances (EC) is indicated.