I have been amazed by the amount of rainfall falling around here over the past two days, with a number of locations getting the equivalent of an entire September's rainfall in 48hr! Warm, humid, and tropical. At my home in north Seattle I had 1.1 inches the first day and 1.05 inches the second! The ground is saturated.
Take a look at the 48-h rainfall analysis from the Seattle Rainwatch web sight (built by the UW and sponsored by the City--Seattle Public Utilities--to allow them to deal with heavy rainfall situations, http://www.atmos.washington.edu/SPU/). Areas from Seattle extending back to Tahoma had over two inches.Here is a wide view...keep in mind Rainwatch is based on calibrating radar imagery using rain gauges and thus is not useful where terrain blockage is significant (over the Cascades, WA Coast for example). The heaviest rain was apparently near Olympia.Olympia has accumulated 4.1 inches of rain in just the past 4 days and 5.3 inches over the past 31 days. September normal at Olympia is 2.0 inches for the entire month.
Over the past 4 days SeaTac has recorded 3.2 inches of rain, normal for the entire month is 1.7 inches. Want more? For the calendar day yesterday Seattle set a new daily record (.78 inches) ...old record .57 inches in 1983. Want even more? So far this month (ending midnight) Sea Tac has received 3.74 inches, which IS THE WETTEST
18 days on record for September at that location. Olympia has the same claim. The all-time wettest Sept for Sea Tac is 5.95 inches and 7.59 inches for Olympia. A really good chance we will break these records.
If you have a sprinkler system, better turn it off.
I was planning on getting my house painted this fall...I have had second thoughts with all this rain!
Why has it been so wet? For several days we have had a persistent configuration of the upper level flow with a low offshore and southwesterly flow over us and Oregon (it has been even worse down there!). With strong SW flow we have had a warm, moist, unstable air streaming over us for days.
Latest NWS Statement released Monday AM:
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