weather discussion

2008-09-07 18:25:17.000 – Jeff Wehrwein,  Summit Intern

Island in the sun.

Yesterday was a return to the days of early August, when rain and fog were a daily occurrence. Even the temperature was reminiscent of August, peaking just below 60 degrees. At the morning synoptic today, our first rain of the month had already accumulated to 2.07 inches over the preceding 24 hours. The average monthly precipitation for September is 8.55 inches, so we received nearly a quarter of our quota in one day. This wet weather was brought to us by the remnants of Hurricane Hanna (and the letter H?) as it passed quickly through the northeast.n

nMany people expected the summit to experience high winds as a result of the hurricane, but actually the highest winds of a hurricane occur at the surface of the earth, near sea level. Since we are higher up in the atmosphere, we’re above the highest winds in the storm. For example, at 5:00 AM this morning Hanna was a tropical storm centered off the coast of Massachusetts with winds at 50 mph. At the same time, winds on Mount Washington were averaging around 30 mph.n

nLater this morning, however, the winds did pick up and the temperature dropped due to the passage of a cold front on the back side of the storm. We also cleared out of the fog unexpectedly and were treated to a phenomenal undercast under a sunny blue sky for much of the day. Seeing the northern presidentials covered in clouds reminded me that that a few hundred vertical feet can make the difference between beautiful views and dreary fog.n

nThe undercast didn’t last, however, and we were back in the fog by mid-afternoon. As high pressure builds behind the cold front, we expect to dip into the mid 30s tonight with a nice chilly breeze in the 40-60 mph range. Surely this is mother nature’s subtle reminder that the August weather isn’t here to stay. I noticed also that the average monthly snowfall for September is 2.20 inches, so I’m optimistic that rain won’t be the only thing falling from the sky this month.

Jeff Wehrwein,  Summit Intern