Winter Weather in Southern Grafton, New Hampshire

Snow squalls crossed the Upper Valley between 5:00 pm and 6:00 pm. The Lebanon Municipal Airport observed a visibility of 1/4 mile and a wind gust of 26 knots at 5:55 pm, and the Plymouth Municipal Airport observed a visibility of 1/4 mile and a wind gust of 27 knots also at 5:55 pm.

An arctic cold front drove through the Northeast on the evening of the 27th. The upper shortwave trough was rapidly transitioning to negatively tilted and at its strongest forcing for ascent as it crossed the local area. The temperatures at 850 hPa dropped from around -10 degrees Celsius in the evening to -19 degrees Celsius by morning. Low level lapse rates were very steep, approaching 9 degrees Celsius per kilometer. This led to some small amounts of low level CAPE, which considering the time of year were quite impressive. The result was a well organized line of snow squalls that affected the majority of the local forecast area, bringing widespread travel impacts due to dangerous short term blizzard conditions.