MWN Blog: Tired of winter? A hint of spring arrives very soon!

Friday, February 11, 2011

Tired of winter? A hint of spring arrives very soon!

U.S. snow depth at midnight on Feb. 11, 2011 (Google Earth image - click for larger version)

After receiving 9.4" of snow in the last 33 days (as recorded at Memphis International Airport), Memphians are excited about the possibility of a lengthy warm spell. This appears to be exactly what we have in store beginning Sunday and lasting right through next week. The upper atmosphere is undergoing a major pattern shift this weekend which will bring a thaw to much of the central and eastern U.S. after record snowfall in many locations. The map above shows snow depth across the United States as of midnight last night (Friday morning) in which 47 of the lower 48 states had snow. For the Mid-South, the pattern shift will mean an extended period of high temperatures in the 60s and milder conditions overnight, as indicated by the MWN Forecast.

The model graphics below show the temperatures at the 5,000-foot (850mb) level of the atmosphere, which are commonly used by forecasters to predict surface high temperatures. The purple line is 0 degrees C (32 F, or the freezing level), while blue lines are sub freezing and red lines are above freezing. Each line is +/- 3 degrees C from it's neighboring line, so the first red line next to the purple line is 3C (or about 37 F), the next one is 6C (or about 42 F), etc. The top graphic (click to enlarge) is the 5,000-foot temperatures last night (Thursday, Feb 10) at 6pm and the bottom graphic is the forecast for next Tuesday evening at 6pm (Feb. 15). Notice that the freezing line (purple) was along the Gulf Coast last night and by Tuesday it will have retreated to the Great Lakes! While blue lines encompassed much of the nation last night, by Tuesday, we're all in the red - a sure sign of a big warm-up! I think we're all ready for a taste of spring.