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 May 16 2025

Week 3-4 Forecast Discussion Valid Sat May 31 2025-Fri Jun 13 2025

The primary seasonal and subseasonal tropical convective signals remain quiet, with El Niño Southern Oscillation (ENSO) neutral conditions persisting across the equatorial Pacific, and an incoherent MJO presentation. Extratropical teleconnections to the tropical convective pattern are typically weak this time of year anyway; therefore, the multivariate linear regression (MLR) statistical tool based primarily on tropical signals was not a strong factor in this Weeks 3-4 outlook. Absent clear subseasonal signals to guide the forecast, dynamical model guidance was utilized heavily to discern any consistent patterns that could drive anomalous temperature or precipitation patterns in early June.

A manually weighted blend of operational dynamical and statistical model guidance resulted in a 500-mb height anomaly pattern that is generally low-amplitude, which is characteristic for the summer season. Height anomalies across the contiguous United States (CONUS) are generally positive in the model guidance, though there are substantive differences among the different model systems. The CFS and JMA both depicted ridging across the Northeast, a feature mostly absent in the GEFS and ECMWF. The CFS also placed a trough across the West, whereas the other model systems showed no negative height anomalies across the CONUS. In the manual blend of this guidance, slight ridging comes through over the Northeast, but there is a greater consensus for ridging across the south-central CONUS. Height anomalies remain near normal across Alaska.

The clearest signal in the temperature guidance favors above-normal temperatures across the south-central CONUS, with the highest probabilities (in excess of 70 percent) across Texas and eastern New Mexico. Given climatology and extreme heat guidance for Weeks 3-4, there is a potential for excessive heat during this period. Above-average temperatures are also favored across much of the remainder of the CONUS, though equal chances are maintained west of the Rockies and across the Northeast, where the guidance was less consistent. Across Alaska, various models show areas of enhanced chances for below-normal temperatures, but there is little consistency, so equal chances are maintained for much of the state. Enhanced chances for above-normal temperatures extend across western Alaska, where there is greater model agreement.

The precipitation outlook also exhibits a high degree of uncertainty, with significant differences present between the operational guidance and experimental tools, such as the ensemble subsampling tool. Much of the guidance favors a wet solution across much of the eastern half of the US, with the strongest agreement on above-median precipitation across the Florida Peninsula and the mid-Mississippi Valley, where probabilities exceed 55 percent. A broader region of 50 to 55 percent chances for above-median precipitation extends across the the northern Plains and upper Midwest. Equal chances are maintained across the Northeast, where model guidance is less consistent. Equal chances are also maintained for much of the western half of the CONUS, although a slight chance for below-median precipitation extends across the south-central CONUS due to anticipated ridging. Across Alaska, model guidance was generally wet, with the highest probabilities for above-median precipitation extending across the southwestern quadrant of the state.

Across Hawaii, above-normal sea surface temperatures and dynamical model guidance favor above-normal temperatures, with probabilities increasing towards the northwestern islands. While precipitation guidance generally favors above-median conditions, the signal is not strong, and this time of year precipitation is primarily driven by moisture arriving via the trade winds. Given the lack of a clear cause for above-median precipitation, equal chances are maintained across the islands.

Temperature Precipitation

FCST FCST

Hilo A55 EC

Kahului A55 EC

Honolulu A60 EC

Lihue A70 EC

Forecaster: Adam Allgood

The next week 3-4 outlook will be issued on Friday, May 23, 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.