Weather Glossary – E

ECMWF – European Centre for Meteorology Forecast model.

EL NINO- A major warming of the equatorial waters in the Pacific Ocean. El Nino events usually occur every 3 to 7 years, and are characterized by shifts in “normal” weather patterns.

ENSO – El Nino-Southern Oscillation.

ENTRAINED / ENTRAINMENT– Refers to the drawing in of moisture (or lack of moisture) into a system. Dry air entrainment into the mid levels of a thunderstorm can enhance the potential for damaging wind gusts. Moisture being entrained into a storm system can enhance precipitation amounts. 

EQUIVALENT POTENTIAL TEMPERATURE– The temperature of a parcel of air after all moisture and latent heat is condensed out of an air parcel then descended to the 1000 mb level. Also known as Theta-E

ETA– “Eta” (from Greek) model generated every 12 hours by NCEP

EVAPORATION – the process of a liquid changing into a vapor or gas.

EXTENDED OUTLOOK – a basic forecast of general weather conditions three to five days in the future.

EXTRAPOLATE– Determining the value of a meteorological value beyond the bounds of a data sample.