Atmospheric patterns, 700 mb and 500 mb height anomalies, statistical data, ECMWF, and Canonical Correlation analysis, observed cases from past summers, sea surface temperatures were analyzed but the effect on the global circulation are expected to be minimal.
A cold episode continued this past month, as indicated by the below-normal sea surface temperatures across the central and east-central equatorial Pacific Ocean. The latest weekly indices were -0.6°C in Nino-3.4 and -0.9°C in Nino-4, with values close to zero in Nino-1+2 and Nino-3. Below-normal subsurface temperatures persisted, with below-normal temperatures dominating the central and eastern equatorial Pacific Ocean. Low-level wind anomalies remained easterly over the western and central Pacific, while upper-level wind anomalies were westerly over the central Pacific. Convection was suppressed over the Date Line and western Pacific and was enhanced over Indonesia.
The IRI multi-model average predicts weak cold episode conditions to continue through February- April 2025 and then transition to ENSO-neutral. The IRI dynamical model average and several of the models from the North American Multi-Model Ensemble predict an earlier transition to ENSO-neutral in January- March 2025. A weak cold episode is less likely to result in conventional winter and spring impacts, though predictable signals can still influence the circulation. In summary, La Niña conditions are expected to persist in the near term, with a transition to ENSO-neutral likely during March- May 2025.
The ECMWF weeklies depict below normal heights across the country with above normal heights over the Arctic and western Canada for week 1. Below normal heights across much of Canada and above normal heights in the East. For week 2. For week 3, above normal heights are forecast in the West and below normal heights across the central and eastern states. By week 4 and beyond, a zonal flow with above normal heights covered much of North America.
The ECMWF monthlies depict above normal heights across much of the nation. The CamSIPS and the SEAS5 are similar.
The ECMWF monthlies and the CamSips depict above normal temperatures across the nation.
TEMPERATURES
Yeloow-2-4°F
Orange-4-6°F
Red-6-8°F or Greater
Mediam Blue 4-6F Below
Dark Blue-6-8F or Great Below
Above normal temperatures are forecast for most of the Four Corners, the Plains to the Atlantic Coast. Anomalies are forecast to be up to 8°F. The remainder of the nation is not expected to exceed normal climatology.
PRECIPITATION
Yellow=-35%
Below
Brown-35-45% Below
Dark
Brown-45-55% Below
Light
Green-30-35% Above
Green-35-45% Above
Dark
Green-45-55%Above
Below-normal precipitation is forecast for most of the Rockies, the Plains and parts of the lower Mississippi Valley and the Southeast. The probability of occurrence is near 35 to 40 percent. Above-normal precipitation is forecast for most of the Midwest into the lower Mid-Atlantic. The probability of occurrence is nearly 35 percent. The remainder of the nation is not expected to exceed normal climatology.
Jim Munley Jr.
http://www.jimmunleywx.com
Forecast Verification