Mid Latitude Lows By Diana L. Duckworth Rustburg High School Campbell County, VA Signature Cloud Pattern Comma Photo: EOS Low forms as cold air pushes south & warm air pushes north along polar front. Sets up counterclockwise rotation; converging air rises.0circulation%20models%201.jpg L Cold Sector Warm Sector Warm sector weather is Thunderstorms Cold Sector weather is warm front weather: steady ppt. Form depends on thermal structure of atmosphere. Warm clouds Cold clouds Warm air Cold air SNOWSLEETFREEZING RAIN D.P.T. < 0C DPT > 0C Wintry Mix Boundaries between types are mixed! Warm front wraps around the Low into the precipitation shield. SNOW MIX RAIN SNOW RAIN SNOW MIX RAIN Low goes up coast noreaster Counterclockwise circulation coastal winds from the northeast!tsoc.org/amsed u/dstreme/ Winter Storms Low passes to west up Ohio Valley Showers & possibly thunderstorms depending on temperatures in warm sector Low passes over central Virginia Wintry mix, depending on temperatures Low passes just to south & up coast near Hatteras SNOW!!!! & LOTS OF IT Predicting the track of a Mid- Latitude Low Steering Winds At 500 mb level Low moves in the direction of the steering winds Moves at the speed of steering winds Storm Tracks Storm tracks follow polar front & jet stream. Intensify in troughs with jet streak (very high jet stream winds 150 mph or more) Polar front is in Canada in summer, so Virginia gets cold front weather. Polar front moves south into U.S. in winter, so Virginia gets warm front weather (more in precipitation shield).