DECEMBER-FEBRUARY 2012-13 90-DAY OUTLOOK
345 PM EDT Tue. Dec. 4, 2012

Atmospheric patterns, 700 MB and 500 MB height anomalies, statistical data, and various models such as the ECMWF monthly, NMME, IMME and the CFSv2, along with observed cases from past such months, data from 1895-2000 were used in this forecast.

Oceanic and atmospheric indices continued to indicate a neutral ENSO conditions. Sea surface temperature anomalies remained fairly steady across much of the central Pacific Ocean. Anomalies between 0 and +0.5 C throughout the east-central equatorial Pacific Ocean,. Anomalies west of the Date Line along the equator are mostly between +0.5C and +1.5C. Atmospheric observations over the tropical Pacific Ocean remained consistent with a neutral ENSO conditions, with convection mostly near normal. Models indicate a continuation of neutral anomalies along the equator in the east-central Pacific through the end of the year.

Enhanced convection was evident across parts of Southeast Asia, South America and Africa as well as south of Hawaii. Suppressed convection developed over parts of the Indian Ocean. The MJO showed signs of weakening during the past week as several observational indicators became considerably less coherent. Most of the dynamical model MJO index forecasts currently indicate little, if any, coherent MJO signal during the next two weeks. Some models and a few statistical forecast tools, however, do indicate the potential for renewed enhanced convection in the western Pacific during the period. Atmospheric Kelvin and Equatorial Rossby wave activity is weak or not well defined and in combination with a potentially weakening MJO, the forecast has high uncertainty with little forecast coverage.

Above normal temperatures are forecast for the West, most of the Plains and into the Mississippi Valley. The probability of above normal temperatures across this region is 56%. The remainder of the nation is not expected to exceed climatological values.

Above normal precipitation is forecast for the Northwest coast, the eastern gulf coast states, the Southeast, the mid-Atlantic and southern new England. The probability of above normal precipitation for this area is 56 percent. Below normal precipitation is forecast for most of the Rockies and the western Plains. The probability of below normal precipitation for this area is 56 percent. The remainder of the nation is not expected to exceed climatological values.


Jim Munley Jr.
www.jimmunleywx.com