WeatherWatcher: Weekly report, hope you like rain

Forecast

Cold Snap and Graphs

Last week's data

Forecast: Like clockwork, the week we celebrate Thanksgiving brings us some of the stormiest and wettest weather we typically see. It's either rain, wind, or cold/snow. This year, rain and wind, and a lot of it. Tuesday looks like it will start the day with heavy rain, totals may amount up to an inch. In the afternoon the rain should ease up however and temperatures will be mild, above normal in the 50's. Wednesday afternoon the rain returns and early indications are pointing to a possible wind event as well for the evening. Thursday more rain is expected, with cooler air moving in and a transition to showers Friday. The weekend looks mostly dry, but the dryness is due to the cold and dry arctic air returning nearby, bringing at least the night time temperatures back down to below freezing.

Cold Snap and Graphs: Last two weeks we had our first cold snap of the season. Arctic air centered over the Rockies and Plains was also partially slipping into Western Washington bringing us the cold and dry weather. For 4 days in a row we had a low temperature below 25°F, and dew points down into the single digits. This was giving us a very low relative humidity for the majority of the sunny weather period. 

I decided to show this dry weather with my usual graphs for the month so far. First is the daily average temperature and daily high and low temperatures. You can see the huge dip in the dark blue line, it also shows how we are back up to a little above the average now. Some of this however is because we've had a habit over the past several years to get our first cold air around the second to the last week of November so the average has been brought down by those semi-annually repeated events. This year the cold was two weeks in, instead of three.

Graphs by Carl Dinse

Graphs by Carl Dinse

The next two graphs show the daily average dew point and the daily rainfall totals for November. Remember that dew point is the temperature at which the current moisture content in the air condenses or saturates. Some of the dew points were down to near 0°F, which means you'll never see fog develop until the actual temperature got to about that temperature. Relative humidities were around the 12-15% range outside.

Graphs by Carl Dinse

Graphs by Carl Dinse

Last week's data:

High temperature: 50.2°F (Thursday)

Low temperature: 23.9°F (Saturday)

Rainiest day: 0.51 inches (Friday)

Total rainfall: 0.55 inches

Warmest day: 47.4°F (Friday)

Coldest day: 31.3°F (Saturday)

Average temperature: 39.3°F

4 year average: 42.8°F

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