Today the humidity has been extraordinary around western Washington and Oregon. I mean sticky. Feels like the southeast U.S. during the summer--and for good reason: we are experiencing very, very high humidities with dew points in the mid to upper 60s in many locations.
(Remember dew point is a very good measure of humidity...high dew points mean lots of water vapor in the atmosphere. Typically this time of the year dew points would be around 50F. )
Here are some dew point values at 5 PM:
Cascade Locks 72F
There is a satellite that senses water vapor from space...take a look below:
Pretty amazing...there is a plume of moisture streaming out of the subtropics from just north of Hawaii....an atmospheric river. You can call it a pineapple express--but it is missing one thing...enough upward motion to give us heavy rain. Want to see a great video of this moisture plume? Check this out:
Here is a simulation of vertically integrated water vapor from the UW forecasting system valid 11 PM...the blues are the highest values and you can see it streaming from the southwest.
The humidity is so large that there has been some condensation in the form of shallow fog over parts of the Sound...which is cold enough to cause this moisture to condense. Some wind was also helpful, since it mixed the water vapor towards the cold surface. Look at this picture sent to me today by Greg Johnson of SkunkBayWeather.com. You see the grey haze near the surface? That is the shallow fog I was talking about.
Now I know for sure that this was the most humid day over the past year so far in terms of dew point ---and here is the proof for Sea Tac:
At Sea Tac the highest dew point of the day was 66F...one degree shy of the ALL TIME RECORD HIGHEST SEPTEMBER DEWPOINT for that location.
And want more extreme weather...head to the LA basin for heat. A number of locations have had their ALL TIME RECORD TEMPERATURES, with observations in the LA area of 113-119F!! Be thankful you are living in the Northwest.