Forecast of the Day • A National Weather Forecasting Contest

Some locations in the Midwest will experience the passage of a dramatic cold front during the day on Thursday. St. Louis, Missouri will begin the day in the warm sector, with temperatures far above average and rain, but then the temperature will plunge with gusty winds after the cold front passes. It may not be easy to forecast the maximum temperature, as the models don't seem to agree how warm it will get before the front arrives. So let's forecast Tmax for St. Louis and see how warm it gets before the big fall.

Question: In a midlatitude cyclone, what is the "warm sector"?