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October 1, 2010

Region sees months of rain in two days

Looks like the rain has finally stopped. But the high water will be running off for some time, and the records set in the past two days will last a long, long time.

The official total at BWI-Marshall Airport topped 6 inches for the 29th and 30th. Additional rain after midnight Friday will likely push the total to about 6.4 inches when the official number is tallied.

Thursday's BWI total of 6.03 inches obliterated the record for the date - 1.60 inches, set in 1920. It also established a new record for a single day in September, breaking the old mark of 5.97 inches, set nearly a century ago, in 1912.

The September total of 8.26 inches makes it the 8th wettest September on record for Baltimore.Clouds Baltimore

1934:  12.41 inches 

1999:  11.50 inches

1876:  10.52 inches

1882:  9.38 inches

1912:  8.75 inches

1975:  8.62 inches

1966:  8.50 inches

2010:  8.26 inches

As impressive as that is, other locations around Baltimore, and especially in Southern Maryland recorded far more rain than that. Some spots took in a couple of months of normal rainfall in a couple of days. Here is a sampling of two-day totals, from the CoCoRaHS Network:Rainy commute

Hollywood, St. Mary's Co.:  11.79 inches

Leonardtown, St. Mary's Co.:  9.92 inches

White Marsh, Baltimore Co.:  9.50 inches

Deale, Anne Arundel Co.:  9.39 inches

Havre de Grace, Harford Co.:  8.43 inches

Severna Park, Anne Arundel Co.:  7.77 inches

Park Hall, St. Mary's Co.:  7.22 inches

Annapolis, Anne Arundel Co.:  6.93 inches

Frederick, Frederick Co.:  3.64 inches

Cumberland, Allegany Co.:  2.41 inches

Salisbury, Wicomico Co.:  2.21 inches

(SUN PHOTO: Frank Roylance)

Posted by Frank Roylance at 7:31 AM | | Comments (6)
Categories: By the numbers


I checked my trusty gauge this morning, Middletown locked in at 6.45 inches since September 29th, and yes, the yard is soggy! We received 1.25 inches alone in a deluge that happened yesteday which lasted just 45 minutes, (4:30-5:15pm)

This whole year has been about breaking records! Amazing stuff!

Where did you get the rainfall numbers you show? I did not see it on the website. Also, I would not be so quick to say these records will last. With the weather we have had this year I think almost anything is possible!

FR: The rainfall numbers come from the CoCoRaHS Network. They are unofficial, but contributed by very serious weather observers.

Imagine how much snow it would have been! Let's hope we're back in balance now and the extremes are finished for a long time to come!

I measured 12.25 inches in my rain gauge, starting Wednesday late morning through Friday morning. Could that be too high? I live in Annapolis, which your list has at 6.93. Why such a difference?

FR: Without knowing anything about the quality of your equipment, I can't say. There is a lot of variability from place to place, but that's pretty extreme.

I need to correct the Middletown total, it was 5.25 inches, not 6.5. The 6.5 included the rain from earlier in the week.

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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff

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