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 EDT Fri Jun 13 2025

Week 3-4 Forecast Discussion Valid Sat Jun 28 2025-Fri Jul 11 2025

El Niño Southern Oscillation (ENSO) neutral conditions persist in the equatorial Pacific Ocean, with weak positive sea surface temperature (SST) anomalies in the eastern central Pacific. The Madden Julian Oscillation (MJO) is inactive with the magnitude of the real-time multivariate MJO (RMM) index recently decreasing. ECMWF and GEFS forecasts of the RMM indicate no clear emergence of an MJO signal in the next couple weeks. Therefore, a multivariate linear regression (MLR) statistical model, based on MJO, ENSO and trend indices was not used in today’s Week 3-4 Outlook. The Week 3-4 Outlook is based primarily on calibrated and uncalibrated dynamical model forecasts of temperature and precipitation from the ECMWF, GEFS, JMA, and CFSv2 models, along with various blends of these forecasts. Evolution of the pattern from the current week 2 forecast, feedbacks between temperature, precipitation and soil moisture, and impacts of sea surface temperature anomalies on coastal regions were also considered.

Dynamical models generally predict positive 500-hPa height anomalies centered to the south of the western or central Aleutian Islands with a trough and negative mid-level height anomalies over the Bering Sea. Negative 500-hPa height anomalies extend across parts of northern Mainland Alaska in the CFSv2, JMA and GEFS ensemble mean forecasts. Dynamical models generally forecast positive 500-hPa height anomalies across the entire contiguous United States (CONUS) during the week 3-4 period, as a ridge retrogresses from east to west over the CONUS from week 2 into week 3-4. Positive 500-hPa height anomalies exceeding 30 meters are centered over parts of the Pacific Northwest, the northern Rockies, and northern High Plains in the manual blend of dynamical models and most individual model forecasts for week 3-4. Dynamical models predict a relative weakening of the positive 500-hPa height anomalies and a trough over the eastern CONUS, with some increase in positive 500-hPa height anomalies over parts of the Northeast in the ECMWF forecast in particular.

Below normal temperatures are favored over parts of western Mainland Alaska ahead of a predicted trough, consistent with all of today’s ensemble mean forecasts. Dynamical model forecasts are less consistent with temperature forecasts for the remainder of the state of Alaska, where equal chances (EC) of above and below normal temperatures is indicated in the Week 3-4 Outlook. Above normal temperatures are favored across almost the entire CONUS, under predicted positive 500-hPa height anomalies. Probabilities for above normal temperatures exceed 60 percent over most of the western CONUS and parts of the northern Plains, under the center of positive mid-level height anomalies. Probabilities for above normal temperatures are moderated along the west coast, and EC is indicated for parts of the California coast, consistent with dynamical model forecasts of cooler temperatures in week 3 along the coast. Probabilities favoring above normal temperatures are moderated for the central Great Lakes region southward into much of the eastern CONUS, under a predicted trough and relatively weaker positive 500-hPa height anomalies. EC is indicated for parts of the Lower Mississippi Valley eastward across the Southeast to the southern Atlantic coast, consistent with potential cooler temperatures in some dynamical model forecasts, partly linked to the prediction of enhanced precipitation and clouds. Above normal temperatures are likely along the immediate Gulf Coast, adjacent to positive sea surface temperature anomalies.

Above median precipitation is favored for western Mainland Alaska in most dynamical models, ahead of a predicted trough. Below median precipitation is favored for parts of the interior northwestern CONUS under the predicted ridge. The eastern tropical Pacific has been active recently leading to increased moisture flow into the western CONUS and enhanced probabilities of above median precipitation for much of the Desert Southwest. Dynamical model forecasts consistently predict above median precipitation for much of the Southeast from the central Gulf Coast to the northern Florida Peninsula and the Georgia and Carolina coasts. Below median precipitation is slightly favored for the southern Florida Peninsula, consistent with all dynamical model forecasts. Greater uncertainty among dynamical model precipitation forecasts leads to EC for above and below median precipitation across remaining areas of the forecast domain.

Above normal temperatures are probable for all of Hawaii in the Week 3-4 Outlook, related to above average SST anomalies surrounding the islands. Above median precipitation is favored for Hawaii, consistent with most dynamical model forecasts and the manual blend.

Temperature Precipitation

FCST FCST

Hilo A60 A55

Kahului A70 A55

Honolulu A70 A55

Lihue A70 A55

Forecaster: Dan Collins

The next week 3-4 outlook will be issued on Friday, Jun 20, 2025

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

These are two category outlooks and differ from official current three category outlooks currently used for the monthly and seasonal forecasts.

The shading on the temperature map depicts the most favored category, either above-normal (A) or below-normal (B) with the solid lines giving the probability ( >50%) of this more likely category (above or below).

The shading on the precipitation map depicts the most favored category, either above-median (A) or below-median (B) with the solid lines giving the probability ( >50%) of this more likely category (above or below).

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