NOAA: Outlook for First 2-Weeks of April in the USA

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Week 3-4 temperature outlook. noaa, today

NOAA just started an experimental week 3-4 outlook – ie a weather outlook for 14-28 days from today.

This week 3-4 outlook is favoring WA and the Northeast the most and doesn’t look good for the majority of the West (above average temps and below average precip forecast).

Week 3-4 precipitation outlook. noaa, today


Prognostic Discussion for Week 3-4 Temperature and Experimental Precipitation Outlooks
NWS Climate Prediction Center College Park MD
300PM EST Fri Mar 16 2018

Week 3-4 Forecast Discussion Valid Sat Mar 31 2018-Fri Apr 13 2018

La Nina conditions currently are present across the equatorial Pacific Ocean. Equatorial sea surface temperatures (SSTs) are below average across the central and eastern Pacific Ocean. Both the La Nina and the coupled atmospheric response to this cold event weakened considerably in recent weeks. The CPC velocity potential based and RMM MJO indices indicate the MJO signal has weakened considerably during the past few weeks, with the enhanced convective phase currently located over the eastern Indian Ocean. The MJO is predicted to continue to weaken over the next two weeks. The Week 3/4 temperature and precipitation outlooks rely primarily on dynamical model forecasts from the NCEP CFS, ECMWF and JMA operational ensemble prediction systems, as well as forecasts from the Subseasonal Experiment (SubX), a multi-model ensemble (MME) of experimental ensemble prediction systems. Consideration is also given to the possible evolution of the predicted circulation pattern for Week-2.

The various model guidance supporting the Week 3-4 outlook is in good agreement today, depicting a trough over the great lakes region, while anomalous ridging is indicated over western Alaska and the Aleutians. The CFS, ECMWF and JMA ensemble means depict near- to above-normal 500-hPa heights over most of the southern and eastern CONUS as well as Alaska, while near- to below-normal 500-hPa heights are indicated over most parts of the north-central CONUS. The CFS and ECMWF favor near-normal 500-hPa heights over Hawaii, while the JMA predicts above-normal 500-hPa heights over Hawaii.

Calibrated temperature forecasts from the individual models and multi-model combinations of these forecasts favor an enhanced likelihood of near- to above-normal temperatures across most of southern CONUS, and near- to below normal temperatures over much of the northern CONUS. This is also supported by the Multiple Linear Regression tool that uses ENSO, MJO, and long-term trend time series. Near- to Above-normal temperatures are forecast over western Alaska, while below-normal temperatures are indicated over eastern Alaska, consistent with dynamical model guidance from SubX.

The various guidance is also in good agreement on the precipitation outlook. Near and downstream of a predicted trough, near- to above-median precipitation is favored over much of the eastern CONUS. The various dynamical guidance as well as statistical guidance is in good agreement on below-median precipitation over the southwestern CONUS and southern Alaska, and above-median precipitation over Washington.

Dynamical model guidance from CFS and ECMWF temperature forecasts indicate increased probabilities of above-normal temperatures for Hawaii during the Week 3-4 period. The CFS/ECMWF/JMA correlation weighted consolidation forecast favors above-median precipitation over Kahului and Honolulu.

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