Well we had another spring deluge here in my Bennington neighborhood in NW Gaithersburg/central Maryland and the surrounding metro area starting late on Thursday, May 15 and extending through mid-morning of Friday, May 16. Flood watches turned to flood warnings throughout the region. Friday morning traffic on the way into my office from Bennington was heavy but luckily my route was not blocked by flooded roads like it generally was in the more rural parts of Montgomery County. The MARC commuter train that normally runs regularly on the eastern extremity of Bennington to and from Washington D.C. did not run on Friday, as the tracks to my NW around Point of Rocks MD bordering up to West Virginia near Harpers Ferry were flooded out from the Potomac and its tributaries. According to my Vantage Pro 2 datalogger which logs data for every 5 minute period, the heaviest rainfall amounts fell between 4:30 AM and 6:50 AM early Friday morning, during which 2.63″ of rain fell. The maximum instantaneous rainfall rate my weather station recorded was 5.88″/hour at 4:41 AM. I was asleep during this heaviest action so I did not observe it, but my Vantage Pro 2 weather station does a great job logging the rainfall amounts while I am sleeping or otherwise occupied.
Both Thursday’s total of 1.06″ and Friday’s total of 2.67″ eclipsed old daily records for greatest 24 hour rainfalls on those days (old records were 0.93″ on Thursday 5/15 and 2.30″ on Friday 5/16). The 2 day event total was 3.73″ was probably not a record for a 2 day rain in May, but I don’t keep those kinds of records conveniently which would require doing a lot of research that I don’t have time for right now. The month of May has received 5.44″ of rain so far which isn’t close to the monthly record yet, but we still have 2+ weeks to go through to add to that total. Right now if the month ended today this May would already be the 12th wettest of all time (35 years of records – going back to 1979). Our spring total rainfall (April and May) already is over 10 inches at 13.10″ – a full spring precipitation analysis will be forthcoming in a few weeks with my May monthly summary.